EI-02785; No of Pages 10 Environment International xxx (2014) xxx–xxx

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The importance of evaluating the physicochemical and toxicological properties of a contaminant for remediating environments affected by chemical incidents S. Wyke ⁎, A. Peña-Fernández, N. Brooke, R. Duarte-Davidson Centre for Radiation, Chemical and Environmental Hazards, Public Health England, UK

a r t i c l e

i n f o

Article history: Received 17 December 2013 Accepted 6 May 2014 Available online xxxx Keywords: Recovery and restoration Chemical incident Physicochemical and toxicological properties Environmental decontamination

a b s t r a c t In the event of a major chemical incident or accident, appropriate tools and technical guidance need to be available to ensure that a robust approach can be adopted for developing a remediation strategy. Remediation and restoration strategies implemented in the aftermath of a chemical incident are a particular concern for public health. As a result an innovative methodology has been developed to help design an effective recovery strategy in the aftermath of a chemical incident that has been developed; the UK Recovery Handbook for Chemical Incidents (UKRHCI). The handbook consists of a six-step decision framework and the use of decision trees specifically designed for three different environments: food production systems, inhabited areas and water environments. It also provides a compendium of evidence-based recovery options (techniques or methods for remediation) that should be selected in relation to their efficacy for removing contaminants from the environment. Selection of effective recovery options in this decision framework involves evaluating the physicochemical and toxicological properties of the chemical(s) involved. Thus, the chemical handbook includes a series of tables with relevant physicochemical and toxicological properties that should be assessed in function of the environment affected. It is essential that the physicochemical properties of a chemical are evaluated and interpreted correctly during the development of a remedial plan in the aftermath of a chemical incident to ensure an effective remedial response. This paper presents a general overview of the key physicochemical and toxicological properties of chemicals that should be evaluated when developing a recovery strategy. Information on how physicochemical properties have impacted on previous remedial responses reported in the literature is also discussed and a number of challenges for remediation are highlighted to include the need to develop novel approaches to remediate sites contaminated by mixtures of chemicals as well as methods for interpreting chemical reactions in different environmental matrices to include how climate change may affect the speciation and mobility of chemicals in the environment. © 2014 Elsevier Ltd. All rights reserved.

1. Introduction The production and use of chemicals has increased globally in recent decades, the Chemical Abstract Service (CAS) database has information on over 75 million unique organic and inorganic substances (CAS, 2013). However, chemical releases are common and may arise from industrial accidents, natural disasters, and conflict or terrorism (WHO, 2009). Chemical incidents can have a significant public health and environmental impact and need to be controlled and managed appropriately. Chemicals occur as liquids, solids or gases and may be a risk to public health by causing direct or indirect, acute or chronic toxic effects. In the aftermath of a chemical incident, the public health risk and hazard to

⁎ Corresponding author at: International Research and Development Group, Centre for Radiation, Chemical and Environmental Hazards, Public Health England, Chilton, OX11 0RQ, UK. Tel.: +44 1235 825283, +44 7798 570724 (mobile). E-mail address: [email protected] (S. Wyke).

humans will depend on the toxicity, dose, route, duration of exposure and the potential for toxic degradation products (Wyke-Sanders et al., 2012). Other important considerations include distance from the source of contamination or the incident and understanding how the chemical behaves in the environment, as the physicochemical properties of the chemical may influence decisions on the remediation strategy (Liu et al., 2008). The immediate response to a chemical incident or crisis is usually coordinated by first-line responders and may involve implementing preliminary protective measures such as sheltering and evacuation of individuals from short-term relatively high risks. These measures may include limiting the spread of contamination by decontaminating people on site (Chilcott, submitted for publication; Duarte-Davidson et al., in press; Hemsley, 2013). Roles and responsibilities during the emergency response are well defined and exercised. However, the process of rebuilding, restoring and rehabilitating the community following an emergency, often termed the “recovery” phase, is not as well defined or practised. There are no exact boundaries between the emergency response to the incident and the recovery and remediation phase, as the

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latter usually lasts as long as the effects of the incident can be expected to persist and continues until the area is returned to normal (Nisbet et al., 2009). It is vital therefore that decisions and actions taken during the acute or emergency response phase consider an early return to normal living and facilitate recovery, remediation and rehabilitating the community following an emergency to return to normality (Cabinet Office, 2004, 2013). Public Health England (PHE) (formerly Health Protection Agency) in collaboration with other UK Government Departments and Agencies and local authorities developed the UK Recovery Handbook for Chemical Incidents (UKRHCI) (Wyke-Sanders et al., 2012). The UKRHCI contains practical, evidence-based guidance and a six-step decision framework for developing a recovery strategy following a chemical incident that includes evaluating and interpreting the physicochemical properties of the chemical involved as this is a key step in informing the development of an effective and appropriate recovery strategy. Recovery strategies have historically been developed based on knowledge of individual chemicals, but this novel approach facilitates the selection of recovery options based on generic information available on physicochemical and toxicological properties making it applicable to a range of chemicals rather than individual chemicals. Other key factors that should be considered prior to developing a remediation response have been addressed in Peña-Fernández et al. (in press-a). This paper presents a general overview of the physicochemical and toxicological properties of chemicals that should be assessed when developing a recovery strategy for the remediation of the environment following a chemical accident or release (including discovery of historical contamination). The interpretations of relevant physicochemical and toxicological properties for remediation are depicted in Table 1. Information on how physicochemical properties have impacted on previous remedial responses reported on the literature, and future challenges for remediation, are also discussed. 1.1. Physical form The physical form of a chemical (solid, liquid or gas at specific temperatures) will influence how it behaves in the environment. Gases and vapours tend to spread out until they are equally distributed throughout the space available to them. Liquids flow with gravity and must be safely contained to prevent further risk of exposure. Solids are in general easier to contain, however solid fibres, dust or smoke can be rapidly dispersed by the air and may present a risk to the public situated in the path of the plume (Wyke-Sanders et al., 2012). Temperature and other meteorological conditions may affect the behaviour of a chemical, for example if water temperature decreases oils may solidify rather than spread across the surface of water, or move in dense patches travelling under the influence of waves and tides (Radović et al., 2012a). The temperature at which a liquid’s vapour pressure equals atmospheric pressure and the liquid turns to vapour is known as its boiling point. Chemicals with a low boiling point are likely to be either gases or very volatile liquids at ambient temperature (DETR, 1999). Highly volatile chemicals are unlikely to be a long-term hazard (Hauschild et al., 2012) but could be a potential inhalational hazard and health risk for response and recovery personnel (Radović et al., 2012a). Increasing temperature can facilitate remediation, for example thermal desorption treatments can be applied to contaminated soils (depending on the contaminant involved) and act by converting chemicals into a more volatile form that evaporates (Chang and Yen, 2006; Wang et al., 2012). 1.2. Toxicity The toxicity and toxicological properties of a chemical and its reaction or degradation by-products will influence the remedial response following a chemical incident, and will need to be assessed on a site

and incident-specific basis (Table 1). Some chemicals although highly toxic to humans may not require active remediation, and natural attenuation may be the most appropriate strategy. An example includes benzene released at sea through crude and light oil spills where little remedial action may be required as benzene is highly volatile and will evaporate rapidly. However, response and remediation actions would be very different if a large spill occurred in an enclosed space. Equally, some contaminants may undergo transformation on surfaces that contain catalytic centres such as metal oxides and sulphides present in rocks, even in the absence of any chemical or biologically active components of the soil. For example, γ-hexachlorocyclohexane (lindane) transforms into its isomer α-hexachlorocyclohexane and becomes partially dechlorinated producing pentachlorocyclohexene (Volchek et al., 2014). Both by-products are less toxic than the original lindane. This transformation may be a contributing factor in natural attenuation and its extent will depend on soil composition. The public perception of risk has to be considered in conjunction with the actual risk to public health. For example, following the discovery of cyanide in two grapes imported into the USA in a consignment from Chile in 1989, public pressure led to the adoption of a conservative approach which resulted in a national ban on Chilean fruit imported into the country (Newman, 1989). In retrospect, taking into account the physicochemical properties of cyanide (highly reactive), and the fact that punctured grapes would decompose rapidly, the response and subsequent ban on imports from Chile in 1989 was probably too precautionary (Newman, 1989). The toxicity of chemicals varies according to speciation and the influence of environmental factors. For example, current water quality standards are based on total metal concentrations; however the toxicity of metals to aquatic life also depends on the chemical speciation as well as water quality variables, including water hardness (calcium and/or magnesium concentration), pH and dissolved organic matter (Qu et al., 2013). Qu et al. (2013) reported that the toxicity of cadmium (Cd) depends on the water hardness and the toxicity of Cd in water can be reduced by increasing calcium and magnesium concentrations (increasing the pH). The degradation of chemicals in the environment can result in endproducts (by-products), which are intermediates that can induce negative health effects to a population or the wider ecosystem. A common example of a reaction by-product is when sodium hypochlorite containing solutions (such as household bleach) are inadvertently mixed with acidbased cleaners (such as lime scale removers) resulting in the production of chlorine gas (HPA, 2007). Equally, chlorine is used to disinfect drinking water, but can react with dissolved natural organic matter leading to the formation of organic by-products such as trihalomethanes, chlorophenols and haloacetic acids (Ritter et al., 2002; Wong et al., 2012). The oxidation of sulphur mustard to its inert form sulphoxide (which has low toxicity) is another example, however if oxidation is allowed to continue the reaction can result in the production of sulphone which is a vesicant and shares many of the dangerous properties of the original sulphur mustard (Backvall, 2010; Inturi et al., 2014). The degradation by-products of cyanobacteria and other aquatic organisms can produce cyanotoxins which can be neurotoxic and hepatotoxic. The Wuxi Water Crisis (China, 2007) was attributed to a combination of stresses associated with eutrophication and industrial and domestic wastewater discharges inadequately regulated that enhanced the bloom of the cyanobacterium Microcystis aeruginosa in Lake Taihu (Yang et al., 2008). Moreover, by-products generated during chemical industrial processes have been largely deposited in an uncontrolled manner around the world (i.e. aerial plume dispersion) and it is important to identify and evaluate industrial waste disposal sites (Vijgen et al., 2011; Wycisk et al., 2013). The production of lindane (one of the most extensively used pesticides after the Second World War until the 1990s) has resulted in global transport of toxic by-products including hexachlorocyclohexane (HCH) isomers due to the high volatility of HCH and aerial plume dispersion (Vijgen et al., 2010, 2011; Willet et al., 1998).

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Table 1 Interpretation of physicochemical properties (adapted from Wyke-Sanders et al., 2012; Brooke, 2014). Physicochemical characteristic

Description

Persistence Units = T ½ median half-life

Water and air (days) b0.042 (1 hour) 0.042–0.42 0.42–4

Toxicity

Partition coefficient between water and octanol Units = KOW

Soil sorption Units = KOC

Vapour pressure (VP) Units = Pascals (Pa)

Henry’s Law constant (Hc) Units = Unitless or in Pa m3/mol

Vapour density (D vapour)

Density of liquid (D liquid)

Viscosity Units = mPa.

Water solubility Units = mg/l or ppm

Interpretation Soil (days) b5 b15 b30

Persistence

Very short-lived Short-lived Moderately short-lived 4–40 30–100 Moderately persistent N40 N100 Highly persistent Sum of adverse effects or the degree of danger posed by a substance to living organisms. Toxicity is generally expressed as a dose–response relationship involving the quantity of substance to which the organisms is exposed and the route of exposure; dermal, ingestion, inhalation or ocular. Gives an indication of relative solubility of a chemical in water and in octanol. High values also give an indication of potential to adsorb to soil and sediments. N1000 : Likely to bioaccumulate (hydrophobic)- High Between 500 and 1000 : Increasing likelihood of bioaccumulating b500: Unlikely to bioaccumulate (hydrophilic)- Low

High persistence Likely to: Remain in the relevant medium and result in exposure Be difficult to decontaminate Unlikely to: Be volatile Be reactive

High KOW Likely to Accumulate in fatty tissue Cross the blood brain barrier Be absorbed across skin Permeate plastic pipes Unlikely to be: Decontaminated by water alone. Measures how readily a chemical is adsorbed to organic High KOC surfaces in the soil matrix and gives an indication of likely Likely to be: persistence in soil. Adsorbed N10,000 : Likely to adsorb Accumulated Between 1000 and 10,000 : Increasing likelihood of Unlikely to be adsorbing Mobile b1000: Unlikely to adsorb A measure of how easily a liquid evaporates or gives off High VP vapours. Likely to: b1.3 × 10−4 Pa: unlikely to volatilise Be an inhalation hazard −4 Evaporate quickly N1.3 × 10 Pa: likely to volatilise Be contained by fixative coatings Indicates the tendency for chemicals to move from the High Hc Likely to: aqueous phase to the gaseous phase. Have potential for volatilisation N1 × 10−4 Higher tendency to volatilise from b1 × 10−4 Lower tendency to volatilise water surfaces Result in exposure via inhalation D N1.29 The relative weight of a gas or vapour compared to air. Likely to: Air is assigned an arbitrary value of 1. If a gas has a vapour density of b1.29 it will generally rise Remain close to the ground and in air. If the vapour density is N1.29 the gas will generally pose a risk to inhabitants sink. DN1 The density (specific gravity) of a liquid is Will: determined by comparing the weight of an equal Sink in water amount of water (Water = 1.0). If the specific gravity is less than 1.0 then it will float, if greater than 1.0 it will sink. This is likely to be an important factor following release to water where the use adsorbent booms/mats could be considered for chemicals that float on water. Viscosity determines how easily a chemical will flow in High Likely to be: an environment. Viscous chemicals are less likely to Difficult to decontaminate re - suspend in the environment. Unlikely to be: Examples: Vacuumed Water: 0.894 (low) Resuspended Corn syrup: 81 (high) Mobile High solubility Water soluble materials (such as acids) may be more easily dispersed in water and have a greater potential to Likely to be: pollute water environments (e.g. groundwater). Many Contaminate groundwater Be decontaminated by water insoluble materials (e.g. petrol) may be spread water-based solutions by flowing water. Water-based decontamination of surfaces may be more Be mobile in the environment/ effective if a chemical is water soluble; removal options Unlikely to be: or active decontamination may be more appropriate for Volatilised Persistent non-water soluble chemicals b10: Negligible solubility Between 10 and 1000: Increasing likelihood of solubilising N1000: Likely to solubilise

Short persistence Likely to be: Volatile Reactive Unlikely to: Require decontamination

Low KOW Likely to be: Mobile Soluble Unlikely to be: Bioaccumulated

Low KOC Likely to be: Mobile Unlikely to be Adsorbed

Low VP Unlikely to: Be an inhalation hazard Persistent Low Hc Likely to: Have a low potential for volatilisation Remain in solution D b1.29 Likely to: Rise and mix in air more easily, but may accumulate in ceiling spaces. Db1 Will: Form a surface film on water

Low Likely to be: Mobile Easier to decontaminate

Low solubility Likely to be: Immobilised by adsorption Unlikely to be: Mobile in the environment Contaminate drinking water

(continued on next page)

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Table 1 (continued) Physicochemical characteristic

Description

Interpretation

Absorption on porous surfaces

The ability of a substance to absorb to porous surfaces (e.g. concrete) is an important consideration as this may influence the effectiveness of remediation technique.

Surface Tension Units = dynes /cm

Chemicals with a low surface tension are more likely to seep into relatively inaccessible surfaces (e.g. between screws/ bolts). Chemicals with a higher surface tension are more likely to accumulate on a surface without penetrating inaccessible areas. Examples, Ethanol: 22.3 (low) Water: 75.6 Mercury: 465 (high)

Absorbs Likely to be Effectively removed by surface removal techniques, or disposal and dismantling High Likely to: Accumulate on a surface

Identification and monitoring of degradation by-products or metabolites are important when considering options such as natural attenuation and bioremediation (Weber et al., 2008). Bioremediation may enhance the mobility of contaminants through the environment and generate degradation products that are more toxic than the parent compound (Juhasz and Naidu, 2000). Bioremediation may also require monitoring and characterisation of metabolites and end-products. There are a series of ecotoxicological tests to assess the toxicity at different trophic levels (Adams et al., 2011; Eom et al., 2007; Kamber et al., 2009; Oleszczuk, 2008; Steliga et al., 2012). Moreover, the analysis of metabolites could also be used to demonstrate exposure (Radović et al., 2012a). Natural attenuation of decabromodiphenyl ether (DecaBDE) results in the parent compound being debrominated over time, resulting in a more mobile and toxic polybrominated diphenyl ether (PBDE) (Schenker et al., 2008), and under thermal stress or UV irradiation, the more toxic polybrominated dibenzofurans (PBDFs) (Kajiwara et al., 2013). Andersson et al. (2009) reported that bioremediation of sludge contaminated with polycyclic aromatic hydrocarbons (PAHs) resulted in an increase in the toxicity of these chemicals, due to formation of more polar PAH degradation by-products, suggesting that ex situ remedial methods may have been more appropriate (i.e. removal of sludge). All these examples highlight the importance of taking into account the possibility that degradation by-products may occur naturally or as a result of remedial action. 1.3. Persistence in the environment Persistence is influenced by the environment the chemical is released into, how rapidly it degrades and how it is dispersed (Brooke, 2014). The presence of organic matter in soil, microbial degradation, exposure to sunlight, temperature and pH can all also influence the half-life of a chemical (Mackay et al., 1996). Incidents involving persistent chemicals are more likely to require rapid action and remediation (Lim and Lynch, 2011). For example, persistent organic pollutants (POPs) and metals can persist in soils and water environments for decades (Augustsson et al., 2011; Weber et al., 2008, 2011) and are a potential public health risk to future generations. Thus, extensive remediation of urban areas and rural farmland was required following the Seveso disaster in 1976 to reduce the levels of dioxins and other organic chemicals (Ramondetta and Repossi, 1998). Soil is a complex matrix (Cachada et al., 2013) and remediation may be influenced by the content of minerals, clay, organic matter and what the soils are traditionally used for. There are different types of soils and each of them may require a different remediation approach such as urban soils (Abramovitch et al., 2003; Peña-Fernández et al., in press-b). Remediating soils contaminated by persistent chemicals (including trace elements) will depend on the traditional use of the soil, and may involve techniques that extract or stabilise these contaminants (Adamu et al., 2013; Pérez-de-Mora et al., 2006a,b), and can include soil

Does not absorb Likely to be : Easier to decontaminate

Likely to: Contaminate inaccessible surfaces or spaces.

washing or irrigation of agricultural land and adjusting soil pH. However, these methods can be labour intensive (Adamu et al., 2013) and may not be appropriate on a large scale (Pérez-de-Mora et al., 2006b), in which case options such as topsoil removal or barriers to seal contamination may be more appropriate. Ecosystems are at risk of being contaminated with POPs such as polyfluoroalkyl compounds (PFCs) from the inappropriate disposal of waste, and landfill may not be the most appropriate method of disposing of waste (Weber et al., 2011). In addition, chemicals that were previously thought to be of no risk to human health or the environment have become emerging chemicals of concern (ECCs) due to their persistence and high toxicity (Wong et al., 2012). PBDEs used as flame or fire retardants in products such as textiles, electronic equipment and insulation materials behave similarly to polychlorinated biphenyls (PCBs) in the environment (Palm et al., 2002). Other persistent chemicals such as perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) are widely distributed across the globe due to their long-range atmospheric and oceanic transport, and are resistant to most conventional chemical and microbial treatment techniques. Efforts are being initiated to develop effective water treatment technologies such as sonochemical degradation for these chemicals (Cheng et al., 2008). The majority of organic chemicals will degrade in the environment (Mackay et al., 1996). Refined oil products such as petrol and light crude oils have volatile components, evaporate, disperse and dissipate in the environment rapidly and are considered non-persistent and theoretically require little action in terms of recovery and remediation (Radović et al., 2012a,b). However, refined oil products also contain high concentrations of toxic and carcinogenic substances, and the impact of these pollutants on public health and the environment could be significant if no remedial action was taken following an accident or spill (White and Baker, 1999). Neuparth et al. (2011) have reported that chemicals that dissolve and disperse easily in aquatic environments have the highest potential for negative ecological impacts. However, heavy fuel oil and crude oils (light, medium and heavy petroleum) have a high proportion of non-volatile components and are viscous. These oils can form stable emulsions in water that can move large distances from the location of the incident. Fractions of these oils may dissolve in water or evaporate, and the remaining components may float or sink depending on their density, have very low biodegradability and become incorporated into soils and sediments (ATSDR, 1999; Levy and Nasseta, 2011; Radović et al., 2012b). Spills or incidents involving these oils have a significant impact on coast lines; wildlife and the economic activity of the area involved (e.g. tourism or fishing) will require active remediation as they are persistent chemicals (White and Baker, 1999). 1.3.1. Soil sorption The physicochemical properties of a chemical will determine if it is mobile or not in soil (Hashim et al., 2011). This can be estimated and measured by determining the octanol–water partitioning coefficient

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(Kow) and the soil organic carbon–water partitioning coefficient (Koc). Kow and Koc can provide an indication of whether or not a chemical will adsorb onto soil or organic matter (Hong et al., 1997; USEPA, 2002). Kow is the concentration of a substance in octanol (soil) divided by the aqueous concentration of the substance, and is a measure of hydrophobicity, being more likely to be adsorbed. The Koc is derived by dividing the soil–water distribution coefficient, Kd (the mass of contaminant adsorbed per unit mass of media divided by the pollutant concentration), by foc (fraction of organic carbon in the soil) (Huang et al., 2005; Larsbo et al., 2013). Koc values are useful in predicting the mobility of the contaminant in the soil, and therefore, if they are likely to persist in soil (Poulson et al., 1997; US EPA, 2002). Both values have been used by the US Environmental Protection Agency (US EPA) to determinate the Soil Screening Values for organic contaminants. For inorganic chemicals, the US EPA uses the soil–water distribution coefficient (Kd) for metals and other inorganic compounds (USEPA, 2002). Large values for Kow and Koc indicate a chemical or substance is more likely to be adsorbed onto soil or organic matter, and will subsequently accumulate and persist in the soil matrix and are less likely to be suitably removed through bioremediation (Juhasz and Naidu, 2000). Chemicals with a Koc N10,000 are likely to adsorb, whereas chemicals with a Koc b 1000, are unlikely to adsorb. For example, the organophosphorus insecticide chlorpyrifos has a high propensity for sorption into soil, and has limited movement through and over the soil profile (Racke, 1993). Therefore topsoil removal or ploughing methods to move contamination away from the soil surface could be considered as remediation techniques if there was significant contamination with chlorpyrifos. The application of surfactants is most widely used to increase the aqueous solubility of non-polar hydrophobic chemicals with a high Kow to form surfactant monomers that aggregate into micelles (Nguyen et al., 2008). However, non-polar ends of surfactants tend to adsorb on soil and this propensity increases when the surfactant concentration is less than the critical micelle concentration. Therefore, an increase in the adsorption of contaminants on soil and sediments can occur (Tong and Yuan, 2012). Desorption is a key pre-step of many remediation techniques; for example microemulsions are used to enhance oil recovery and aquifer remediation, since micelles can enhance contaminant solubilisation through the production of ultralow interfacial tension (Nguyen et al., 2008). The Kd can be used to estimate the mobility of chemicals from soil to groundwater and potential for leaching (Hansen et al., 1999; Hou et al., 2013; Huang et al., 2005). Briggs (1981) reported that the movement of organic chemicals from the soil surface decreased with increasing Kd, and is related with the organic matter. For non-ionized organic compounds, the relation between Kd and Kow is the same, as soil organic matter determines the adsorption for these chemicals. A high Kd value indicates high chemical (mainly inorganic chemicals such as metals and metalloids) retention in the solid phase (soil or sediments) resulting in low metal solubility (Shaheen et al., 2013), and high sorption to soil. Meanwhile, chemicals with a low Kd have high leaching potential (Leal et al., 2013). Thus, the use of soil treatments such as lime have shown a high affinity (i.e. a high Kd) for the sorption of cadmium, copper, lead and zinc from aqueous solutions (Shaheen et al., 2013); so therefore chemical incidents involving mixtures of heavy metals application of soil treatment (i.e. lime) should be considered to reduce the risk of spread and leaching into other environments (Sastre et al., 2007). The composition of the soil and its texture (i.e. soil particle size) can also influence the sorption of contaminants and the remediation strategy (Peña-Fernández, 2011; Sastre et al., 2007; Volchek et al., 2013; Wang et al., 2012). For example, clay may act as a potential barrier to immobilise contaminants (Sarkar et al., 2007), such as arsenic, which is negatively correlated with clay content of soil (Das et al., 2013). Determining the soil texture can be crucial to ensure an appropriate remediation technique is implemented, for example soil washing/ irrigation is more effective in soils with a clay and silt content below 30–50%

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(Dermont et al., 2008). Chemical and biological remediation techniques have limited efficacy in low-permeability soils such as clay, peat, kaolinite, high-purity fine quartz, sodium and sand–montmorillonite mixtures as contact between the contaminant and the remedial agent is difficult. However, electrokinetic soil remediation has shown high removal efficiencies (Tong and Yuan, 2012; Virkutyte et al., 2002). Electromigration of the pollutant does not depend on the pore size of the soil, and it is particularly efficient in metal-contaminated soils with a high clay content (Virkutyte et al., 2002). The physicochemical properties of the soil may also affect sorption of pollutants into the soil matrix (PeñaFernández, 2011). For example, the mobility of heavy metals in soil is related to soil pH, as heavy metals are more mobile in acidic soils (Madejón et al., 2006). The soil organic matter content in soils is also important; lignin, chitin and cellulose are precursors of soil organic matter and have different sorption affinities for hydrophobic organic compounds, and can reduce the mobility and bioavailability of polar and non-polar chemicals (Jardine et al., 2013; Wang and Xing, 2007). Soil quality is an important parameter, and organic and inorganic treatment of soils can enhance remediation and restoration by increasing the total organic carbon (TOC) in soil. The TOC can improve fertility, structure and water retention capacity, which are important factors for the reclamation of a degraded soil (Asensio et al., 2013; Madejón et al., 2006). Adjusting the pH of soil can reduce the solubility and bioavailability of contaminants such as metals and metalloids (Aguilar et al., 2004; Madejón et al., 2006; Moreno-Jiménez et al., 2012), decreasing their potential to enter the food chain. Thus, applying organic treatments to soils can be beneficial in restoring soils and potentially reducing the need for later additions of nitrogen, phosphorous, and potassium fertilizers (Cañero et al., 2012). 1.3.2. Bioavailability, bioaccessibility and bioaccumulation Bioavailability, bioaccessibility and bioaccumulation are properties that are directly related to the persistence and fate of the chemical in the environment and should be taken into account in any recovery and restoration strategy. The term “bioavailable” refers to the amount of compound that can enter into organisms and “bioaccessible” to the total amount of contaminant in the environment, which is available to enter into living organisms. For remediation purposes, it is more important to determine what is bioaccessible over time at a given site rather than what is bioavailable (Semple et al., 2004), although the bioavailability of a substance is strongly related to the characterisation of risks (Pacini, 2008). Thus, Madejón et al. (2006) have suggested that the solubility and bioavailability of trace elements in soils is more important for remediation purposes rather than total concentration. Phosphate treatments can immobilise lead (Pb) in soil through the formation of pyromorphite (insoluble lead phosphate), therefore reducing the bioavailability of Pb in soil (Hettiarachchi et al., 2001). In calcareous soils, the application of phosphoric acid can also significantly reduce the bioavailability of Pb (Yang and Mosby, 2006), and soil treatments with high concentrations of carbonate can stabilise metals and metalloids in soils (Garrido, 2008), as carbonates enhance metal retention in soil (Sastre et al., 2007). The Kow is also useful to assess the risk of bioaccumulation of a chemical (Hansen et al., 1999; Licht et al., 2004; Mackay et al., 2013) (Table 1) and is often used as a bioaccumulation assessment criterion (Mackay et al., 2013). Bioaccumulation refers to the accumulation of substances in an organism. Substances with a log Kow higher than 5.0 (i.e. Kow N 50,000) are likely to bioaccumulate and are lipophilic. Meanwhile, chemicals with log Kow b 5.0 are unlikely to bioaccumulate. Generally, chemicals with a Kow N 105 are considered lipophilic, and with values of Kow N 106, highly lipophilic (Mackay and Fraser, 2000). Thomann (1995) reported that in water environments, chemicals with a log Kow value of b3 the ingestion of contaminated water is the most significant route of exposure for humans, but with chemicals with a log of Kow N 3, ingestion of fish becomes the most likely source

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of exposure that may result in negative health effects. Thomann (1995) also suggests that incidents involving chemicals with a high Kow require bioaccumulation and biomagnification studies to determine the longterm public health impact; meanwhile chemicals with a log Kow b 3 are potentially suitable for bioremediation. Biomagnification is used here to refer to the process whereby the concentration of a chemical increases progressively as it moves up the food chain. Lipophylic or hydrophobic chemicals are more likely to bioaccumulate in the biota. PCBs are hydrophobic and can bioaccumulate and biomagnify in the food chain, or remain adsorbed in sediment or on suspended particles in the water column (Gdaniec-Pietryka et al., 2013; Yu et al., 2013), requiring constant monitoring. Contrarily, polar or hydrophilic chemicals are often highly mobile in the environment and generally do not bioaccumulate in the food chain unless the exposure is prolonged or chronic. However, a notable exception is polar-persistent organic pollutants (PPOPs) since they are highly soluble in water. PPOPs such as trifluoroacetic acid (TFA), chlorodifluoroacetic acid (CDFA), and perfluorooctane sulfonate (PFOS) are persistent and water soluble. Thus, these compounds are unlikely to bioaccumulate due to their physicochemical properties (Ritter et al., 2002) although they have been detected in animals and humans (Cheng et al., 2008; Giesy and Kannan, 2001). Recently, Oliaei et al. (2013) have reported that PFOS and other longchained perfluorinated sulfonates and carboxilates are bioaccumulative and biomagnify despite their water solubility. In oil spills at sea, lower weight aromatic and polar compounds will dissolve rapidly, yet in terrestrial environments, crude and heavy fuel oils may soak into the ground, which occurred in the pipeline spills in northern Alberta, Canada (Blenkinsopp et al., 1996). Untreated terrestrial oil spills are not usually subjected to any dilution, and bioremediation may be an effective remediation technique (Prince et al., 2003). Lipophilic, hydrophobic or non-polar chemicals are more likely to bioaccumulate in biota and up through the food chain as they are persistent (Ritter et al., 2002). For example, lipophilic pesticides such as dichlorodiphenyltrichloroethane (DDT), chlordane, dieldrin and endosulfan partition rapidly into organic matrices such as bed sediments and persist for many years (Ritter et al., 2002). Generally, highly lipophilic POPs like polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) are considered non-mobile (Weber et al., 2008), but it is recommended to evaluate the chemical congener involved as some PCDD/Fs can leach from landfills into groundwater, possibly because of a colloid-facilitated transport (Persson et al., 2008). 1.4. Vapour pressure Vapour pressure (VP) is a measure of how easily a chemical will evaporate and the tendency of a chemical to volatilise. Vapour pressure is temperature dependent and chemicals with VP values at 20 °C b1.3 × 10− 4 Pa will be unlikely to volatilise, meanwhile chemicals with values N1.3 × 10−4 Pa will be more likely to volatilise, will evaporate quickly and might be an inhalational health risk but are often less persistent (Table 1) (DETR, 1999). In marine environments floating substances will not evaporate if the VP is b300 × 10−4 Pa, but will evaporate quickly if the VP is N 3000 × 10−4 Pa (GESAMP, 2002). Although volatilisation can potentially dissipate a chemical contaminant and facilitate remediation, it can also contribute to the further spread and transfer of contamination to the atmosphere (Barro et al., 2009). Methyl metacrylate (liquid) has a VP of 3900 × 10−4 Pa at 20 °C (i.e. rapidly evaporates), but metacrylate vapours are highly flammable, explosive and toxic (Le Floch et al., 2012). POPs belong to the volatile organic compounds (VOCs) and semivolatile organic compounds (SVOCs) categories, and include PCBs, PCDD/Fs and other polychlorinated compounds and polycyclic aromatic hydrocarbons (Barro et al., 2009). Atmospheric deposition should also be considered for VOCs and other volatile chemicals (e.g. mercury) as they can result in secondary contamination of land and water environments (Ritter et al., 2002; Sweetman et al., 2005).

1.5. Henry’s law constant (Hc) Henry’s law constant (Hc) provides an indication of the partitioning of a chemical between the aqueous and gaseous phase. Hc is a function of vapour pressure (VP) and solubility, and is temperature dependent (Lim and Lynch, 2011). Chemicals with a high Hc are more likely to move by vapour diffusion (Wyke-Sanders et al., 2012). Volatile chemicals are usually defined as having a Hc N 10−5 atm m3/mol and vapour pressure N 1 mm Hg at 25 °C (NJDEP, 2013). VOCs with a Hc below 0.05 tend to be very soluble and remain in water (Lim and Lynch, 2011) therefore Hc is important to consider when developing a recovery strategy for water environments (Table 1). Methyl tert-butyl ether (MTBE) has a Hc value between 0.012 and 0.029 at 10 and 25 ºC in water environments (Lim and Lynch, 2011). If the chemical contaminant is nonpersistent and evaporates rapidly, a remediation response may not be required though this will depend on whether the chemical is a potential risk to humans or not. 1.6. Vapour density (D vapour) and density of liquid (D liquid) Vapour density is temperature dependent, and also changes as a function of fluid pressure and chemical composition (Wright et al., 2010). Vapour density generally decreases for most chemicals when temperature increases (Table 1). Chemical vapours that are heavier than air (b1.0) tend to accumulate in low-lying areas (i.e. bottom of stairwells or underground spaces) or in the event of a spill at sea, heavy vapours such as xylene could pose a significant public health risk to populations that live near or close to the coast line (Le Floch et al., 2012). Substances with a specific gravity lower than 1.0 will float on water. This is the case for lighter-than-water non-aqueous phase liquids (LNAPLs) such as light and medium crude oils and nonhalogenated solvents. However, denser-than-water non-aqueous phase liquids (DNAPLs) such as halogenated solvents have specific gravity values greater than 1.0, and they sink in water (Mercer and Cohen, 1990). Therefore, for incidents on water involving LNAPLs, remediation measures such as booms, dams, absorbent materials and dispersants may be considered following a spill as these chemicals “float” on the water surface. The specific gravity of seawater is 1.035, but the behaviour of chemicals in relation to their density in seawater is not well understood for some substances, as the majority of published data involve fresh water environments rather than marine and salt waters. For example the Ievoli Sun (UK, 2000) spill involved the release of styrene in the English Channel; due to the specific gravity of styrene and weather conditions at the time of the incident, the spilled styrene formed slicks on the sea surface that quickly evaporated and formed an invisible toxic cloud at the fate of aerial currents (Law et al., 2003; Le Floch et al., 2012). 1.7. Viscosity The viscosity of a chemical determines how easily it flows within an environment and can be used to estimate the movement and behaviour of a chemical. Viscosity is affected by temperature, and generally decreases as the temperature increases. Highly viscous chemicals have limited mobility and are less likely to re-suspend in the environment, although decontamination may be complex, since removal techniques will be limited and will require more energy (increasing the costs of remediation). For its part, chemicals with a low viscosity are able to spread rapidly in water environments making them difficult to contain, whereas highly dense and viscous chemicals (i.e. oils) are relatively easier to contain by using booms (Radović et al., 2012b). 1.8. Water solubility and surface tension Chemicals with a low solubility are more likely to be immobilised by adsorption (DETR, 1999). The hydrophobicity of organic compounds is

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higher in marine environments than in freshwater; therefore organic compounds are less soluble in saltwater (Xie et al., 1997). Most petroleum hydrocarbons are highly insoluble in water, which is why dispersants are used in crude and heavy fuel oil spills to accelerate the dispersion in the water column to increase the available surface area (Atlas, 2011). Water-based decontamination (e.g. scrubbing, steam cleaning, pressure hosing, etc.) may be more effective if a chemical is water soluble, and physical removal options or active decontamination may be more appropriate for non-water soluble chemicals (WykeSanders et al., 2012). Other recovery techniques such as bioremediation can be inefficient if the chemical is highly water soluble, as is the case of methyl tert-butyl eter (Lim and Lynch, 2011). Water solubility of chemicals will also depend of environmental characteristics. Thus, the solubility of organic compounds will be modified by the presence of electrolytes (salts). Xie et al. (1997) have observed a general decrease of solubility of organic compounds in seawater. The surface tension of a chemical will influence its capacity to emulsify, which is an important factor for chemicals spilled in water environments, since emulsification promotes natural dispersion in the water column. For example, xylene can form slicks and dissolve in water although it is classed as a VOC (VP = 890 Pa) (Le Floch et al., 2012). Surface tension can also be used to estimate the likelihood of a chemical seeping into relatively inaccessible surfaces (Wyke-Sanders et al., 2012) and could be useful to assess the impact of a chemical incident occurring in an inhabited area (Table 1). Chemicals with a high surface tension such as mercury (465 dynes/cm) are likely to accumulate on a surface without penetrating inaccessible spaces, such as bolts, screws or man-hole covers.

2. Risk of entry into the food chain A poor or inappropriate understanding of factors such as bioaccessibility, bioaccumulation and biomagnification may put populations at risk in the event of a chemical incident. Thus following a chemical release it is important to obtain monitoring and to undertake health risk assessments to estimate the potential for the chemicals to enter the food chain. Consumption of vegetables and other crops, or meat from animals that have grazed in contaminated environments or been fed contaminated foodstuffs can result in chemical contaminants being introduced into the food chain (Peña-Fernández et al., 2013; Torres et al., 2013a,b; WHO, 2010; Wyke-Sanders et al., 2012). For example, in 2008 animal feed was found to be contaminated with dioxins and PCBs that led to the global withdrawal and disposal of thousands of tonnes of meat products, together with the cull and disposal of thousands of pigs and cattle, costing several hundred million Euros (Mortimer, 2010). Metals and metalloids have also been found to bioaccumulate and biomagnify in the biota due to its inorganic characteristics (Madejón et al., 2013; Peña-Fernández, 2011). Besides, the risk assessment study should also evaluate the appropriateness of the recovery technique prior implementation, specifically in bioremediation. For example, PCBs can become more water soluble following microbial degradation and cause secondary contamination (Hedman et al., 2009). The risk assessment should also consider factors such as the potential for the pollutant to translocate into fruits or other edible parts of plants where plants are used for phytoremediation (Madejón et al., 2013) and the potential for chelation/gastrointestinal absorption can be relevant for chemical removal from livestock where meat is to be used for human consumption. Gupta and Gupta (1998) have reported that selenium toxicity in animals can be controlled by gastric lavage, resuscitation, and the use of chelating agents during the acute phase. For its part, Peña et al. (2007) have reported that silicon and silicic acid may be provided to mammals to decrease the absorption of aluminium by blocking uptake through the gastrointestinal tract. Biological half-life of the chemical in livestock is also important; it is more difficult to eliminate/excrete lipophilic pollutants from the body.

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3. Dealing with emerging threats Nanoecotoxicology is an emerging discipline (Handy et al., 2008) with possible useful new techniques to consider. Nanoscale zerovalent iron (NZVI) particles can transform diverse environmental contaminants such as chlorinated organic compounds, inorganic compounds and metals to less toxic or inert compounds. Fajardo et al. (2012) have demonstrated the effectiveness of nanoparticles on immobilising lead and zinc in polluted soils, although further investigation is required to determine effects on natural organisms and the soil ecology. International concern is also increasing regarding the potential of pharmaceutical compounds to contaminate the environment readily through pharmaceutical and hospital effluents, and excretion from humans and livestock, with deleterious effects such as antibiotic resistance in bacteria in ecosystems (Elmolla and Chaudhuri, 2010). Photocatalytic processes are a promising method in water treatment for removal and mineralisation of organic pollutants. For example, titanium dioxide (TiO2) photocatalysis can be used to degrade pharmaceutical compounds and drugs such as antibiotics (Yahiat et al., 2011) and organic compounds as methyl tert-butyl ether (Lim and Lynch, 2011). 4. Future challenges for remediation The basic principle of evaluating the physicochemical properties of a chemical to determine how it behaves in the environment is a key step in informing the development of an effective and appropriate recovery strategy. However, the majority of available information on how to predict and assess a chemical’s behaviour in the environment (including different surface types) is derived from laboratory studies, which may underestimate the influence of environmental factors. There are a number of challenges that need addressing that will help improve the remediation strategy in the aftermath of a chemical incident. Some are highlighted below. As chemical incidents can involve chemical mixtures (PeñaFernández et al., in press-a), further research is required to understand how co-contaminants behave in the environment, as this can facilitate or exacerbate recovery and remediation. There is also a need for improved methods of remediation that apply scientific and engineering knowledge, taking into account the physicochemical properties of chemicals and how they behave in the environment. Regarding the characterisation of the site and fate of contaminants in the environment, innovative methods for interpreting chemical reactions on land or in water environments need to be developed. Mathematical models have shown to be useful as a tool for evaluating different remediation strategies, supported by a good understanding of the physical and chemical mechanisms controlling the movement, reactions, transformation and fate of chemicals in the environment. However, the characterisation of these processes and the site is complex and requires more studies. New devices to contain anthropologic and industrial wastes are in development to contain and retain contaminants from urban runoff (Hilliges et al., 2013) which could be adapted for remediation purposes. This line of research is important as there is an increased number of contaminated sites where measures have been introduced to remediate them but that have failed after relatively short time spans (Weber et al., 2008). Phytoremediation (i.e. the use of plants) as a potential long-term, non-invasive remediation technique to absorb contamination from the soil can be a successful strategy following large scale incidents (Madejón et al., 2013). The environment can change for various reasons, although one of the most significant is due to anthropogenic climate change. Our knowledge about how climate change can affect the speciation and mobility of chemicals in the environment is limited. Augustsson et al. (2011) reported that soil moisture, groundwater recharge, hydraulic conductivity, Kd, and bioconcentration in contaminated soils may be affected by

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climate change (Weber et al., 2008). Extreme weather events may include increased flooding, and higher temperatures, that result in increased leaching and volatilisation, enhancing contamination. In some areas, longer drying periods or higher intensity rainfall events could result in damage to landfills and other containment systems. Furthermore the sea level is expected to rise affecting coast lines, pollutants could potentially be moved from land to sea (Weber et al., 2011). Therefore, climatic and geological issues should be considered in any long-term remediation strategy that involves significant ecosystem contamination. In this sense, natural attenuation, containment measures and disposal of waste may be factors that should be considered over periods extending to centuries.

References Abramovitch RA, ChangQing L, Hicks E, Sinard J. In situ remediation of soils contaminated with toxic metal ions using microwave energy. Chemosphere 2003;53:1077–85. Adams RH, Kanga-Leyva K, Guzmán-Osorio FJ, Escalante-Espinoza E. Comparison of moisture management methods for the bioremediation of hydrocarbon contaminated soil. Afr J Biotechnol 2011;10:394–404. Adamu H, Luter L, Lawan MM, Umar BA. Chemical speciation: a strategic pathway for insightful risk assessment and decision making for remediation of toxic metal contamination. Environ Pollut 2013;2(3):92–9. Aguilar J, Dorronso C, Fernández E, Fernández J, García I, Martín F, et al. Soil pollution by a pyrite mine spill in Spain: evolution in time. Environ Pollut 2004;132(3):395–401. Andersson E, Rotander A, von Kronhelm T, Berggren A, Ivarsson P, Hollert H, et al. AhR agonist and genotoxicant bioavailability in a PAH-contaminated soil undergoing biological treatment. Environ Sci Pollut Res Int 2009;16(5):521–30. Asensio V, Covelo E, Kandeler E. Soil management of copper mine tailing soils. Sludge amendment and tree vegetation could improve biological soil quality. Sci Total Environ 2013;456–457:82–90. Atlas RM. Oil biodegradation and bioremediation: a tale of the two worst spills in the US history. Environ Sci Technol 2011;45:6709–15. ATSDR (Agency for toxic substances, disease registry). Toxicological profile for fuel oils. Atlanta, GA: US Department of Health and Human Services, Public Health Service; 1995. Augustsson A, Filipsson M, berg T, Bergb ck B. Climate change. An uncertainty factor in risk analysis of contaminated land. Sci Total Environ 2011;409:4693–700. Backvall JE. Modern Oxidation Methods2nd ed. 978-3-527-32320-3; 2010. Barro R, Regueiro J, Llompart M, Garcia-Jares C. Analysis of industrial contaminants in indoor air: part 1. Volatile organic compounds, carbonyl compounds, polycyclic aromatic hydrocarbons and polychlorinated biphenyls. J Chromatogr A 2009;1216(3): 540–66. Blenkinsopp S, Sergy G, Lambert P, Wang Z, Zoltai SC, Siltanen RMLong-term recovery of peat bogs oiled by pipeline spills in northern Alberta. Proceedings of the nineteenth Arctic and marine oil spill program technical seminarOttawa: Environment Canada; 1996. p. 1335–54. Briggs GG. Adsorption of pesticides by some Australian soils. Aust J Soil Res 1981;19:61–8. Brooke N. Physicochemical properties. In: Bradley N, Harrison H, Hodgson G, Kamanyire Kibble, Murray V, editors. Essentials of Environmental Public Health Science. A Handbook for Field ProfessionalsOxford University Press 978-0-19-968288-1; 2014. Cabinet Office. The Civil Contingencies Act, UK, Statutory Instrument 2012 No 624; 2004. Cabinet Office. Strategic National Guidance. The decontamination of buildings, infrastructure and open environment exposed to chemical, biological and radiological or nuclear materials; 2013. Cachada A, Dias AC, Pato P, Mieiro C, Rocha-Santos T, Pereira ME, et al. Major inputs and mobility of potentially toxic elements contamination in urban areas. Environ Monit Assess 2013;185(1):279–94. Cañero AI, Becerra D, Cornejo J, Hermosín MC, Albarrán A, López-Piñeiro A, et al. Transformation of organic wastes in soil: effect on bentazone behaviour. Sci Total Environ 2012;433:198–205. Chang TC, Yen JH. On-site mercury-contaminated soils remediation by using thermal desorption technology. J Hazard Mater 2006;B128:208–17. Chemical Abstract Service. CAS Registry 2013. Available at http://www.cas.org/content/ chemical-substances, 2013. [Accessed Nov 2013]. Cheng J, Vecitis CD, Park H, Mader BT, Hoffmann MR. Sonochemical degradation of perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) in landfill groundwater: environmental matrix effects. Environ Sci Technol 2008;42:8057–63. Chilcott RP. Managing mass casualties and decontamination. Environ Int 2014n. http://dx. doi.org/10.1016/j.envint.2014.02.006. [submitted]. Das S, Jean JS, Kar S. Bioaccessibility and health risk assessment of arsenic in arsenicenriched soils, Central India. Ecotoxicol Environ Saf 2013;92:252–7. Dermont G, Bergeron M, Mercier G, Richer-Lafleche M. Soil washing for metal removal: a review of physical/chemical technologies and field applications. J Hazard Mater 2008; 152:1–31. DETR. Department of the Environment, Transport and the Regions (DETR). Environmental Sampling After a Chemical Accident; 1999. Duarte-Davidson R, Orford R, Wyke S, Griffiths M, Amlôt R, Chilcott R. Recent advances to address European Union Health Security from cross border chemical health threats. Environ Int 2014. http://dx.doi.org/10.1016/j.envint.2014.01.003. [in press].

Elmolla ES, Chaudhuri M. Photocatalytic degradation of amoxicillin, ampicillin and cloxacillin antibiotics in aqueous solution using UV/TiO2 and UV/H2O2/TiO2 photocatalysis. Desalination 2010;252(1–3):46–52. Eom IC, Rast C, Veber AM, Vasseur P. Ecotoxicity of polycyclic aromatic hydrocarbon (PAH)-contaminated soil. Ecotoxicol Environ Saf 2007;67:190–205. Fajardo C, Ortíz LT, Rodríguez-Membibre ML, Nande M, Lobo MC, Martín M. Assessing the impact of zero-valent iron (ZVI) nanotechnology on soil microbial structure and functionality: a molecular approach. Chemosphere 2012;86:802–8. Garrido H. Guadiamar, science, technique and restoration. The mining accident ten years after. Consejo Superior de Investigaciones Científicas (CSIC); 2008. Gdaniec-Pietryka M, Mechlińska A, Wolska L, Galuszka A, Namieśnik J. Remobilization of polychlorinated biphenyls from sediment and its consequences for their transport in river waters. Environ Monit Assess 2013;185:4449–59. GESAMP. (IMO/FAO/UNESCO-IOC/WMO/WHO/IAEA/UN/UNEP Joint group of experts on the Scientific Aspects of Marine Environmental Protection). Revised GESAMP Hazard Evaluation Procedure for Chemical Substances Carried by Ships. Rep. Stud. Gesamp No. 64. London: IMO; 2002 [126 pp.]. Giesy JP, Kannan K. Global distribution of perfluorooctane sulfonate and related compounds in wildlife. Environ Sci Technol 2001;2001:1339–42. Gupta UC, Gupta SC. Trace element toxicity relationship to crop production and livestock and human health: implication for management. Commun Soil Sci Plant Anal 1998; 29(11–14):1491–522. Handy RD, Von der Kammer F, Lead JR, Hasselow M, Owen R, Crane M. The ecotoxicology and chemistry of manufactured nanoparticles. Ecotoxicology 2008;17:287–314. Hansen BG, Paya-Perez AB, Rahman M, Larsen BR. QSARs for Kow and Koc of PCB congeners: a critical examination of data, assumptions and statistical approaches. Chemosphere 1999:2209–28. Hashim MA, Mukhopadhyay S, Sahu JN, Sengupta B. Remediation technologies for heavy metal contaminated groundwater. J Environ Manage 2011;92(10):2355–88. Hauschild VD, Watson A, Bock R. Decontamination and management of human remains following incidents of hazardous chemical release. Am J Disaster Med 2012;7(1):5–29. Hedman JE, Tocca JS, Gunnarsson JS. Remobilization of polychlorinated biphenyl from Baltic Sea sediment: comparing the roles of bioturbation and physical resuspension. Environ Toxicol Chem 2009;28:2241–9. Hemsley T. Initial operation response (IOR) to a CBRN incident. Chem Hazards Poisons Rep 2013;23:17–8. Hettiarachchi GM, Pierzynski GM, Ransom MD. In situ stabilization of soil lead using phosphorus. J Environ Qual 2001;30(4):1214–21. Hilliges R, Schriewer A, Helmreich B. A three-stage treatment system for highly polluted urban road runoff. J Environ Manag 2013;128:306–12. Hong H, Wang L, Han S, Zhang Z, Zou G. Prediction of soil adsorption coefficient Koc for phenylthio, phenylsulfinyl and phenylsulfonyl acetates. Chemosphere 1997;34(4): 827–34. Hou H, Yao N, Li JN, Wei Y, Zhao L, Zhang J, et al. Migration and leaching risk of extraneous antimony in three representative soils of China: lysimeter and batch experiments. Chemosphere 2013;93(9):1980–8. HPA (Health Protection Agency). Chemical compendia. Public Health Advice for Sodium Hypochlorite. Available http://www.hpa.org.uk/webc/hpawebfile/ hpaweb_c/1194947350070, 2007. Huang HC, Lee JF, Chao HP, Yeh PW, Yang YF, Liao WL. The influences of soild-phase organic constituents on the partition of aliphatic and aromatic organic contaminants. J Colloid Interface Sci 2005;286:127–33. Inturi S, Tewari-Singh N, Agarwal C, White CW, Agarwal R. Activation of DNA damage repair pathways in response to nitrogen mustard-induced DNA damage and toxicity in skin keratinocytes. Mutat Res 2014;763-764C:53–63. Jardine PM, Stewart MA, Barnett MO, Basta NT, Brooks SC, Fendorf S, et al. Influence of soil geochemical and physical properties on chromium (VI) sorption and bioaccessibility. Environ Sci Technol 2013;47(19):11241–8. Juhasz AL, Naidu R. Bioremediation of high molecular weight polycyclic aromatic hydrocarbons: a review of the microbial degradation of benzo[a]pyrene. Int Biodeterior Biodegrad 2000;45:57–88. Kajiwara N, Desborough J, Harrad S, Takigami H. Photolysis of brominated flame retardants in textiles exposed to natural sunlight. Environ Sci Process Impacts 2013;15(3):656–60. Kamber M, Flückiger-Isler S, Engelhardt G, Jaeckh R, Zeiger E. Comparison of the Ames II and traditional Ames test responses with respect to mutagenicity, strain specificities, need for metabolism and correlation with rodent carcinogenicity. Mutagenesis 2009; 24:359–66. Larsbo M, Löfstrand E, de Veer DV, Ulén B. Pesticide leaching from two Swedish topsoils of contrasting texture amended with biochar. J Contam Hydrol 2013;147:73–81. Law RJ, Kelly C, Matthiessen P, Aldridge J. The loss of the chemical tanker Ievoli Sun in the English Channel, October 2000. Mar Pollut Bull 2003;46:254–7. Le Floch S, Fuhrer M, Slangen P, Aprin L. Environmental parameter effects on the fate of chemical slick. In: Sunil Dr Kumar, editor. Air quality—monitoring and modelling 978-953-51-0161-1; 2012. Leal RMP, Alleoni LRF, Tornisielo VL, Regitano JB. Sorption of fluoroquinolones and sulfonamides in 13 Brazilian soils. Chemosphere 2013;92:979–85. Levy BS, Nasseta WJ. The adverse health effects of oil spills: a review of the literature and a framework for medically evaluating exposed individuals. Int J Occup Environ Health 2011;17(2):161–7. Licht O, Weyers A, Nagel R. Ecotoxicological characterisation and classification of existing chemicals. Environ Sci Pollut Res 2004;11(5):291–6. Lim LLP, Lynch R. Hydraulic performance of a proposed in situ photocatalytic reactor for degradation of MTBE in water. Chemosphere 2011;82:613–20. Liu R, Liu H, Wan D, Yang M. Characterization of the Songhua River sediments and evaluation of their adsorption behaviour for nitrobenzene. J Environ Sci (China) 2008; 20(7):796–802.

Please cite this article as: Wyke S, et al, The importance of evaluating the physicochemical and toxicological properties of a contaminant for remediating environments affect..., Environ Int (2014), http://dx.doi.org/10.1016/j.envint.2014.05.002

S. Wyke et al. / Environment International xxx (2014) xxx–xxx Mackay D, Fraser A. Bioaccumulation of persistent organic chemicals: mechanisms and models. Environ Pollut 2000;110:375–91. Mackay D, Di Guardo A, Paterson S, Kicsi G, Cowan CE. Assessing the fate of new and existing chemicals: a five stage process. Environ Toxicol Chem 1996;15:1618–26. Mackay D, Arnot JA, Gobas FAPC, Powell DE. Mathematical relationships between metrics of chemical bioaccumulation in fish. Environ Toxicol Chem 2013;32(7):1459–66. Madejón E, Pérez de Mora A, Felipe E, Burgos P, Cabrera F. Soil amendments reduce trace element solubility in a contaminated soil and allow regrowth of natural vegetation. Environ Pollut 2006;139:40–52. Madejón P, Ciadamidaro L, Marañón T, Murillo JM. Long-term biomonitoring of soil contamination using poplar trees: accumulation of trace elements in leaves and fruits. Int J Phytoremediation 2013;15:602–14. Mercer JW, Cohen RM. A review of immiscible fluids in the subsurface: properties, models, characterization and remediation. J Contam Hydrol 1990;6:107–63. Moreno-Jiménez E, Esteban E, Carpena-Ruiz RO, Lobo MC. Phytostabilisation with Mediterranean shrubs and liming improved soil quality in a pot experiment with a pyrite mine soil. J Hazard Mater 2012;201–202:52–9. Mortimer D. The Irish dioxin incident, December 2008. Chem Hazards Poisons Rep 2010; 17:6–9. Neuparth T, Moreira S, Santos MM, Reis-Henriques MA. Hazardous and noxious substances (HNS) in the marine environment: prioritizing HNS that pose major risk in a European context. Mar Pollut Bull 2011;62:21–8. Newman AR. The great fruit scares of 1989. Anal Chem 1989;61(14):861–3. Nguyen TT, Youssef NH, McInerney MJ, Sabatini DA. Rhamnolipid biosurfactant mixtures for environmental remediation. Water Res 2008;42:1735–43. Nisbet A, Brown J, Jones A, Rochford H, Hammond D, Cabianca T. The UK Recovery Handbooks for Radiation Incidents v3. Available https://www.gov.uk/government/publications/uk-recovery-handbook-for-radiation-incidents-and-associated-publications, 2009. NJDEP. Vapour Intrusion Technical Guidance, Version 3. Trenton, NJ: New Jersey Department of Environmental Protection; 2013 [Available at: http://www.nj.gov/dep/srp/ guidance/vaporintrusion/vig_main.pdf]. Oleszczuk P. Forms of polycyclic aromatic hydrocarbon in the formation of sewage sludge toxicity to Heterocypris incongruens. Sci Total Environ 2008;404:94–102. Oliaei F, Kriens D, Weber R, Watson A. PFOS and PFC releases and associated pollution from a PFC production plant in Minnesota (USA). Environ Sci Pollut Res 2013;20: 1977–92. Pacini N. Environmental background assessment: basic principles and practice. Ann Ist Super Sanita 2008;3:258–67. Palm A, Cousins IT, Mackay D, Tysklind M, Metcalfe C, Alaee M. Assessing the environmental fate of chemicals of emerging concern: a case study of the polybrominated diphenyl ethers. Environ Pollut 2002;117(2):195–213. Peña A, Meseguer I, González-Muñoz MJ. Influencia del consumo moderado de cerveza en la toxicocinética del aluminio: estudio agudo. Nutr Hosp 2007;22(3):371–6. Peña-Fernández A. Presencia y distribución medioambiental de metales pesados y metaloides en Alcalá de Henares, Madrid. PhD Thesis Evaluación del riesgo para la población y biomonitorización de la población escolar. University of Alcalá; 2011 [Available at: http://dspace.uah.es/dspace/handle/10017/9510]. Peña-Fernández A, Wyke S, Duarte-Davidson R. Recovery, remediation and environmental decontamination—practical aspects associated with developing a recovery strategy following a chemical incident. Chem Hazards Poisons Rep 2013;23:22–4. Peña-Fernández A, Wyke S, Brooke N. Duarte-Davidson R. Factors influencing recovery and restoration following a chemical incident. Environ Int 2014. [in press]. Peña-Fernández A, González-Muñoz MJ, Lobo-Bedmar MC. Establishing the importance of human health risk assessment for metals and metalloids in urban environments. Environ Int 2014. http://dx.doi.org/10.1016/j.envint.2014.04.007. [in press]. Pérez-de-Mora A, Madejón E, Burgos P, Cabrera F. Trace element availability and plant growth in a mine-spill contaminated soil under assisted natural remediation II. Plants. Sci Total Environ 2006a;363:38–45. Pérez-de-Mora A, Burgos P, Madejón E, Cabrera F, Jaeckel P, Schloter M. Microbial community structure and function in a soil contaminated by heavy metals: effects of plant growth and different amendments. Soil Biol Biochem 2006b;38: 327–41. Persson Y, Shchukarev A, Oberg L, Tysklind M. Dioxins, chlorophenols and other chlorinated organic pollutants in colloidal and water fractions of groundwater from a contaminated sawmill site. Environ Sci Pollut Res Int 2008;15(6):463–71. Poulson SR, Drever JI, Colberg JS. Estimation of K oc values for deuterated benzene, toluene, and ethylbenzene, and application to ground water contamination studies. Chemosphere 1997;35(10):2215–24. Prince RC, Garrett RM, Bare RE, Grossman MJ, Townsend T, Suflita JM, et al. The roles of photooxidation and biodegradation in long-term weathering of crude and heavy fuel oils. Spill Sci Technol Bull 2003:145–56. Qu R, Wang X, Liu Z, Yan Z, Wang Z. Development of a model to predict the effect of water chemistry on the acute toxicity of cadmium to Photobacterium phosphoreum. J Hazard Mater 2013;262:288–96. Racke KD. Environmental fate of chlorpyrifos. Rev Environ Contam Toxicol 1993;131: 1–150. Radović JR, Domínguez C, Laffont K, Díez S, Readman JW, Albaigés J, et al. Compositional properties characterizing commonly transported oils and controlling their fate in the marine environment. J Environ Monit 2012a;14:3220–9. Radović JR, Rial D, Lyons BP, Harman C, Viñas L, Beiras R, et al. Post-incident monitoring to evaluate environmental damage from shipping incidents: chemical and biological assessments. J Environ Manag 2012b;109:136–53. Ramondetta M, Repossi A. Seveso: vent’ anni doppo. Dall’ Incidente al Bosco delle Querce. Capitolo3: Le Richerche della Fondazione No 32. Fondazione Lombardia per L’Ambiente; 1998.

9

Ritter L, Solomon K, Sibley P, Hall K, Keen P, Mattu G, et al. Sources, pathways and relative risks of contaminants in surface water and groundwater: a perspective prepared for the Walkerton inquiry. J Toxicol Environ Health A 2002;65(11):1–142. Sarkar D, Makris KC, Parra-Noonan MT, Datta R. Effect of soil properties on arsenic fractionation and bioaccessibility in cattle and sheep dipping vat sites. Environ Int 2007;33(2):164–9. Sastre J, Rauret G, Vidal M. Sorption-desorption test to assess the risk derived from metal contamination and organic soils. Environ Int 2007;33:246–56. Schenker U, Soltermann F, Scheringer M, Hungerbühler K. Modeling the environmental fate of polybrominated diphenyl ethers (PBDEs): the importance of photolysis for the formation of lighter PBDEs. Environ Sci Technol 2008;42(24):9244–9. Semple KT, Doick KJ, Jones KC, Burauel P, Craven A, Harms H. Defining bioavailability and bioaccessibility of contaminated soil and sediment is complicated. Environ Sci Technol 2004;38(12):228A–31A. Shaheen SM, FI Eissa, Ghanem KM, Gamal El-Din HM, Al Anany FS. Heavy metals removal from aqueous solutions and wastewaters by using various byproducts. J Environ Manag 2013;128:514–21. Steliga T, Jakubowicz P, Kapusta P. Changes in the toxicity during in situ bioremediation of weathered drill wastes contaminated with petroleum hydrocarbons. Bioresour Technol 2012;125:1–10. Sweetman AJ, Valle MD, Prevedouros K, Jones KC. The role of soil organic carbon in the global cycling of persistent organic pollutants (POPs): interpreting and modelling field data. Chemosphere 2005;60(7):959–72. Thomann RV. Modelling organic chemical fate in aquatic systems: significance of bioaccumulation and relevan time-space scales. Environ Health Perspect 1995;103(5):53–7. Tong M, Yuan S. Physiochemical technologies for HCB remediation and disposal: a review. J Hazard Mater 2012;229–230:1–14. Torres JPM, Fróes-Asmus CIR, Weber R, Vijgen JMH. HCH contamination from former pesticide production in Brazil-a challenge for the Stockholm Convention implementation. Environ Sci Pollut Res 2013a;20:1951–7. Torres JPM, Leite C, Krauss T, Weber R. Landfill mining from a deposit of the chlorine/organochlorine industry as source of dioxin contamination of the responsible processes. Environ Sci Pollut Res 2013b;20:1958–65. USEPA (US Environmental Protection Agency). Supplemental guidance for developing soil screening levels for superfund sites. OSWER 9355.4-24. Solid Waste and Emergency Response; 2002. Vijgen J, Abhilash PC, Li YF, Lal R, Forter M, Torres J, et al. HCH isomers as new Stockholm Convention POPs-are we on the way to manage lindane (γ-HCH), and waste HCH isomer (α- and β-HCH) pollution around the world? Environ Sci Pollut Res 2010;5: 363–93. Vijgen J, Abhilash PC, Li YF, Lal R, Forter M, Torres J, et al. Hexachlorocyclohexane (HCH) as new Stockholm Convention POPs-a global perspective on the management of Lindane and its waste isomers. Environ Sci Pollut Res 2011;18:152–62. Virkutyte J, Sillanpää M, Latostenmaa P. Electrokinetic soil remediation-critical overview. Sci Total Environ 2002;289:97–121. Volchek K, Brown CE, Velicogna D. Evaluation of sodium lignosulfonate for the remediation of chromium-contaminated soil and water. Int J Innov Sustain Dev 2013;7(3): 289–302. Volchek K, Thouin G, Kuang W, Li K, Tezel FH, Brown CE. The release of lindane from contaminated building materials. Environ Sci Pollut Res 2014. http://dx.doi.org/10.1007/ s11356-014-2742-x. [in press]. Wang X, Xing B. Importance of structural makeup of biopolymers for organic contamination sorption. Environ Sci Technol 2007;41:3559–65. Wang J, Feng X, Anderson CWN, Xing Y, Shang L. Remediation of mercury contaminated sites. A review. J Hazard Mater 2012;221–222:1–18. Weber R, Gaus C, Tysklind M, Johnston P, Forter M, Hollert H, et al. Dioxin- and POPcontaminated sites. Contemporary and future relevance and challenges: overview on background, aims and scope of the series. Environ Sci Pollut Int 2008;15(5): 363–93. Weber R, Watson A, Forter M, Oliaei F. Persistent organic pollutants and landfills—a review of past experiences and future challenges. Waste Manag Res 2011;29(1):107–21. White IC, Baker JM. The Sea Empress Oil Spill in Context. The International Tanker Owners Pollution Federation Ltd; 1999 [Available at: http://www.itopf.co.uk/_ assets/documents/seeec.pdf]. WHO. Manual for the public health management of chemical incidents; 2009. WHO. Dioxins and their effects on human health. WHO 2010; 2010. p. 225 [Available at: http://www.who.int/mediacentre/factsheets/fs225/en/]. Willet KL, Ulrich E, Hites R. Differential toxicity and environmental fates of hexachlorocyclohexane isomers. Environ Sci Tech 1998;32(15):2197–207. Wong MH, Armour MA, Naidu R, Man M. Persistent toxic substances: sources, fates and effects. Rev Environ Health 2012;27(4):207–13. Wright DJ, Pedit JA, Gasda SE, Farthing MW, Murphy LL, Knight SR, et al. Dense, viscous brine behaviour in heterogeneous porous medium systems. J Contam Hydrol 2010; 115(1–4):46–63. Wycisk P, Stollberg R, Neumann C, Gossel W, Weiss H, Weber R. Integrated methodology for assessing the HCH groundwater pollution at the multi-source contaminated mega-site Bitterfeld/Wolfen. Environ Sci Pollut Res 2013;20:1907–71. Wyke-Sanders S, Brooke N, Dobney A, Baker D, Murray V. The UK Recovery Handbook for Chemical Incidents, version 1. Available: https://www.gov.uk/government/ publications/uk-recovery-handbook-for-chemical-incidents-and-associatedpublications, 2012. Xie WH, Shiu WY, Mackay D. A review of the effect of salts on the solubility of organic compounds in seawater. Mar Environ Res 1997;44(4):429–44. Yahiat S, Fourcade F, Brosillon S, Amrane A. Removal of antibiotics by an integrated process coupling photocatalysis and biological treatment-case of tetracycline and tylosin. Inter Biodeterior Biodegrad 2011;65:997–1003.

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Yang J, Mosby D. Field assessment of treatment efficacy by three methods of phosphoric acid application in lead-contaminated urban soil. Sci Total Environ 2006;366:136–42. Yang M, Yu J, Li Z, Guo M, Burch M, Lin FT. Taihu Lake noy to blame for Wuxi’s woe. Science 2008;319:158.

Yu J, Wang T, Han S, Wang P, Zhang Q, Jiang G. Distribution of polychlorinated biphenyls in an urban riparian zone affected by wastewater treatment plant effluent and the transfer to terrestrial compartment by invertebrates. Sci Total Environ 2013; 463–464:252–7.

Please cite this article as: Wyke S, et al, The importance of evaluating the physicochemical and toxicological properties of a contaminant for remediating environments affect..., Environ Int (2014), http://dx.doi.org/10.1016/j.envint.2014.05.002