Chemicals Regulation Assessment

Review Articles

Environmental Hazard -

Assessment of Chemicals and Products

Part II: Persistence and Degradability of Organic Chemicals Walter K16pffer C. A. U. GmbH, Daimlerstrafle 23, D-63303 Dreieich/Frankfurt, Germany

Abstract Part II: Persistence and Degradability of Organic Chemicals The criteria "Persistence" and "Degradability" are defined and explained, starting from the "functional" definition of the environment. In this definition, the environment is the counterpart of the technosphere, which consists of all processes controlled by man. A substance is persistent if there are no sinks (degradation processes). It is shown that persistence is the central and most important criterium of environmental hazard assessment of organic chemicals. It follows that all substances released into the environment should be degradable, preferentially into small inorganic molecules (mineralization). As examples for persistent substances, the polychlorinated biphenyls (PCB), the chlorofluorohydrocarbons (CFC), his (2-ethylhexyl) phthalate (DEHP), and 2,3,7,8-tetrachloro-dibenzo-dioxin (TCDD) are discussed. Finally, an attempt to quantify persistence is made.

1

Introduction

In Part I of this series [1] general hazard assessment principles for chemicals and products have been presented and discussed. In this paper, which is an extension and actualisation of [2], two of the most important criteria for the environmental assessment of chemicals - essentially of organic, anthropogenic substances - are discussed: persistence and degradability, which are complementary to each other: persistence is the absence of degradability in the environment. These criteria are primarily appropriate in assessing chemicals which may distribute in the environmental media air, water, and soil in molecular dispersion. Sometimes, however, also more complex products containing chemicals or consisting of materials produced by the chemical industry are requested to be degradable in the environment. This is especially true for packaging materials which may end up partly as "litter". The degradability of products is not required if they are recycled, incinerated or dumped into land fills; it is required for composting as the ultimate waste removal. In order to distinguish "Persistence" as a (negative) criterium of environmental hazard assessment [1,2,6,7,1 6 - 18] from the (positive) notion of durability or longevity during the use of products, it is helpful to remember the "functional" definition of the environment proposed by FRISCHEet al. [6,7]. According to this definition, the environment is the counterpart of the "technosphere" which comprises that part of the world which is controlled by man; the environment con-

108

versely consists of all processes and systems not controlled by man. The above mentioned litter, for example, belongs to the technosphere, since, in general, it can be collected and disposed of; in everyday language, however, litter is considered as an environmental problem. A similar consideration applies to landfills, which also belong to the technosphere, as long as they are tight toward air, soil and ground water. It is also clear that the manufacture and intended use of products belongs to the technosphere whereas their disposal may lead partly or fully into the environment (by discharge into air and water etc.). Volatile chemicals may be released into the air during or immediately after use and thus in general enter the environment. For sewage treatment plants, the borderline between the technosphere and the environment was defined and exemplified by the author, using the functional definition of the environment [27]. However, the functional definition of the environment complements but does not replace the more "material" ones, which define the environment by the media (air, water, soil) and the ecosystems including man [3,4]: Water, air, land, and all plants and man and other animals living therein, and the interrelationships which exist among them (definition used in the US chemicals act (TSCA), quoted in [3]). It has also been suggested to distinguish between the natural and the social environment [8]; in this context, we are dealo hag here with the natural environment whose quality is essential for the survival of mankind [1]. This preference of strictly environmental criteria cannot be substantiated on scientific evidence alone [5,8], a problem which is always encountered in valuation procedures. General principles applicable to the assessment of persistent chemicals are the "Vorsorgeprinzip" [8] and POPPER'S philosophy of learning from mistakes [25,26,85]. It is important to note that the environment, independent of the exact definition ("functional" or "material") is much too complicated and poorly understood to predict the effects of chemicals and products reliably. This has to be taken into account in any reasonable environmental assessment method.

2 2.1

Persistence of Chemicals Early Observations

A prominent and visual example for the existence and effects of persistent chemicals is the formation of foam in rivers ESPR-Environ. Sci.& Pollut. Res. 1 (2) 108-116 (1994) 9 ecomed publishers, D-86899 Landsberg, Germany

Review Articles and sewage treatment plants, which was observed in the years of beginning post-war (World War II) affluence [9,11,14]. It was soon recognized that the foaming was mostly due to the biologically non-degradable or refractory [10] tenside sodium tetrapropylene-benzene sulfonate (TPBS) [11 ] which was used as active ingredient in the detergents of that time. Replacement of TPBS by sodium linear alkylbenzene sulfonate (LAS), which essentially consists of an aerobically degradable mixture of n-dodecylbenzene sulfonates, decreased the water pollution considerably. However, foaming can be observed even today, indicating insufficient capacities (or the absence of) sewage treatment plants and - still - the use of some poorly degradable tensides. This is also shown by high amounts of not or partly degraded tensides in sewage sludges [27,73]. A second early case of recognized persistence is the insecticide 1,1-bis(4-chlorophenyl)-2,2,2-trichloro-ethane (DDT) [12]. This substance can be detected using sensitive analytical techniques in most sediments, sewage sludges, and in the fattissues of animals and man. In the environment, DDT is slowly transformed into the even more stable 1,1-bis(4-chlorophenyl)-2,2-dichloro-ethene (DDE) [13]. This transformation product has very similar physical and chemical properties compared to the parent compound DDT, and can also be detected with a high sensitivity. In Germany, DDT was banned by federal law in 1972. The ubiquitous distribution of DDT and DDE as well as that of several other transformation- and coproducts of commercial DDT is well documented in hundreds of publications [12]. The concentrations observed after the ban of DDT diminished only slowly, due to very slow degradation and the continuing "import" from countries where DDT is still used [1] via the atmosphere and via products originating from these countries. Subsequently, other highly chlorinated substances, such as hexachlorobenzene (HCB) [15], the polychlorinated biphenyls (PCB), and several highly chlorinated pesticides were detected and recognized as ubiquitous environmental contaminants. The common principle of these "Xenobiotics" [16] is their slow degradation or persistence, as stressed by Korte [16,17], combined with their lipophilicity and ability to accumulate. Persistence, however, is not restricted to chlorinated and lipophilic compounds. Full credit to "Persistence" as an environmental assessment criterium per se, i.e. also for substances without known adverse effects, was given by STEPHENSON [18] (slightly shortened): "The question of the importance attached to persistence as an effect in itself is a very difficult one. On the face of it there appears little reason to be concerned about a material which, even though present in the environment, is not causing any detectable damage. On the other hand, persistent materials, because of this property, will accumulate in the environment for as long as they are released. Since the environment is not effective at cleansing itself of these materials, they will remain for indefinite periods . . . . The problem could become entirely out of control and it would be extremely difficult if not impossible to do anything about it."

ESPR-Environ. Sci. & Pollut. Res. I (2) 1994

Chemicals Regulation Assessment

The consequent use of this criterium allowed STEPHENSON [18] to identify and rank important environmental chemicals, which were systematically underrated - or even ignored according to other scoring systems [1] due to the absence of any alarming toxicity scores. Thus, toxicity alone is inappropriate for environmental hazard assessment of chemicals. 2.2 2.2.1

Rationale for Persistence as the Central Criterium of Environmental Hazard assessment of Chemicals Some Important Terms

The Degradation of substances in the environment may first lead to well defined products which in some cases may be more stable than the mother substance (see DDT -~ DDE). This partial degradation is frequently called "Transformation", the products are called transformation products, or, only in the case of biodegradation, metabolites. Complete degradation to the inorganic molecules H20, CO2, HC1 etc. is usually designated as "Mineralization" [16]. The chemical processes causing the degradation of organic chemicals are called "Sinks" [2,6,19]. Deviating from this definition, the term sink is often used for both chemical and physical processes which remove a substance - often only temporarely - from a given compartment of the environment. Such physical processes are volatilization, raining out, dry deposition, adsorption and many others. These processes do not remove the substance from the environment and are therefore not suitable for characterizing the degradability of a chemical. Inorganic substances are better characterized by defining their Speciation, which often changes in going from one compartment to the other, i.e. during Transfer processes. The Persistence of a substance is the result of either the absence or inefficiency of sinks or of the inability of a substance to reach potential sinks [19]. To illustrate this second point, which is far more general than the first one: consider a substance which is well soluble in water, and which is emitted only into this compartment. This substance may not reach a sink located in the troposphere - e.g. the reaction with OH-radicals - if the vapour pressure and the Henry coefficient H (H = equilibrium conc. in air / conc. in water [13,20]) is low [19]. If furthermore sinks are absent in water (hydrolysis, photo- and biodegradation), this substance is correctly assigned as "persistent", although it is in principle degradable. If, on the other hand, the substance slowly evaporates from water (medium H), the rate of volatilization will determine the rate of overall degradation, assuming the actual sink in the troposphere is a fast reaction [19]. A possible quantification of persistence is discussed in section 4. A list of the 10 most important sinks of organic substances [6,19] is given in Table 1. Each sink actually consists of a group of related reactions since a complete compilation of all possible environmental degradation reactions would be impossible. A substance may be called degradable if one or more sinks are available and actually reached, given a certain use pattern and set of physical-chemical parameters determining the distribution (environmental exposure).

109

Chemicals Regulation Assessment

Review Articles

Table 1: List of Sinks of Organic Substances in the Environment [19] No.

Sink

Mechanism*

Indirect photochemical transformation in the gas phase of the troposphere

pc

Direct photochemical transformation in the gas phase ("photolysis")

pc

3

Biodegradation in water

bio

4

Hydrolysis

pc

5

Photochemical degradation in water (direct and indirect)

pc

Biodegradation / modification by water plants

bio

7

Biodegradation in soil

bio

8

Photodegradation in the adsorbed state

pc

9

Biodegradation / modification by terrestrial plants

bio

Anaerobic-reductive degradation (biotic and abiotic) in sediments

bio + pc

1 2

6

10

* bio: biochemical processes; pc: physical/chemical processes

A special criterium related to persistence is Accumulation (better: ability to accumulate). Although not restricted to persistent chemicals, accumulation is common among them. The concentration reached in certain places (e.g. sediments, fat tissues) can be several orders of magnitude higher than in the surrounding medium [21]. Sometimes, even easily degradable chemicals can accumulate, as in the case of the oxidatively unstable polycyclic aromatic hydrocarbons (PAH) in anoxic sediments [22] where they are protected from oxygen.

2.2.2

Persistence as the Central Environmental Assessment Criterium

In the following, reasons are given to support the thesis that Persistence is the central and most important criterium to be applied in assessing the environmental hazard of a substance [2,6,7] in exactly the same sense as human toxicity is the central and most important criterium in assessing the hazard posed by a chemical in the workplace. The reasoning rests essentially on two arguments: The first, immediately convincing argument says that only persistent substances, if released to the environment, can be enriched to significant concentrations in air, water and soil. All other chemicals are rapidly degraded so that in a steady state of input and degradation only small concentrations can be achieved. For degradable substances, the concentrations measured depend dramatically on the distance from the sources. This variation was used by JUNG~. [74] ingeniously as a measure of the degradability of atmospheric pollutants, the most persistent chemicals showing the smallest variation of measured concentrations and the smallest average hemispheric North/South concentration ratio.

110

The degree of enrichment depends also, in addition to persistence, on the amount released into the environment and on the dispersion tendency (mobility) of a given substance. Low mobility leads to high local concentrations near point sources, high mobility causes, if combined with persistence, ubiquitous distribution. This general enrichment tendency of persistent chemicals in the environment can be enforced by the above defined, more specific accumulation in animals, plants, soil constituents, or sediments. For introduction of the second argument, for purely didactic reasons, the workplace (belonging to the technosphere [6,7,29]) and the environment are analyzed comparatively with regard to the protected objects [2,6]: 1) Workplace: The objects to be protected are (adult) human beings at 8 hours exposure per day (5 days week). 2) Environment: The objects to be protected are, in principle, all biological species which exist together in innumerable biotopes and ecosystems (up to the biosphere as a whole [1]), the performance of these ecosystems, and mankind as part of them and as the endpoint of many food chains, and finally the composition of the environmental media as the basis of life on earth. We may add the conservation of natural beauty and wildlife as a further important goal in environmental protection. If the hazard posed by a specific chemical is assessed for the two areas, it is sufficient for the working place assessment to determine the human toxicity, since man is the only target considered. This assessment is certainly not an easy task, but experience tells us that it can be done with a high level of confidence by carefully extrapolating the results of animal experiments and by evaluating other relevant observations (e.g. accidents) [23]. In the case of nongenotoxic chemicals it is even possible to define scientifically sound limiting values, which are close to the no-observed-effect level (NOEL) for adults. For the environment, on the other hand, no comparable testing and evaluation is possible due to the extreme diversity of objects and ecosystems to be protected, the functioning of which is known, if at all, only in a very preliminary way. It is unthinkable that even a small fraction of the species involved, of the exposure routes etc. can be considered or that a representative choice of biotopes and ecosystems could be included. In ecosystems, basically different effects (compared to toxicity toward individuals) can occur, e.g. the chemical communication system can be disturbed [10], an effect which has nothing to do at all with some simple ecotoxicity parameters measured in standard testing schemes. Indirect noxious effects may or will be caused by changes in the absorption of solar radiation in the atmosphere [24], leading to increased short-wavelength UV-radiation intensity or increasing temperatures. Both effects cannot be calculated with precision and others may not yet be detected. The simple "single species" tests used predominantly for "ecotoxicity" testing also cannot simulate any synergistic effects by different pollutants with each other or with natural constituents of the environment. ESPR-Environ. Sci. & Pollut. Res. I (2) 1994

Review Articles

Chemicals Regulation Assessment

T o make things worse, even if an "ideal" testing system was possible, it could not be better than the state of scientific knowledge at the time being. Persistent chemicals, however, stay in the environment for a long time (in the extreme case, forever) and cannot be called back by any means, if distributed ubiquitously. For this reason, the exposure cannot be terminated, once a severe noxious effect will be recognized in the future [18]. In principle, of course, ecotoxicity would be the favoured criterium in environmental hazard assessment. As shown above, however, ecotoxicity cannot be measured with a sufficient degree of confidence. Persistence, therefore, replaces ecotoxicity as the central criterium without, of course, making superfluous or obsolete the conventional toxicity and ecotoxicity testing and the other general criteria discussed in Part I [1]. This is the most important conclusion from the second argument. It can furthermore be argued [7] that production and use of chemicals always constitute a kind of field experiment, the risk of which can be diminished by careful testing according to the chemical legislation, but never be absolutely avoided. If negative consequences are recognized, the "field experiment" can be terminated by banning the production of the chemical now unmasked as dangerous under the prerequisit of its degradability. The substance will only disappear from the environment if it is degradable, the rate of disappearance depending on the kinetics of the processes involved. Truly persistent chemicals, however, will stay in the environment for a very long time and the adverse effects will decline only slowly. As a conclusion of both arguments, persistent chemicals should not be allowed to enter the environment. Exceptions from this rule, e.g. in cases of high risks in the technosphere (explosions etc.) posed by substitutes should be carefully assessed, even if socalled dosed systems are supposed to contain the persistent chemical. The experience shows that it is very difficult to prevent chemicals from entering the environment by small "leaks" of the technosphere. One has to be even more careful if a given substance is not only persistent, but also mobile and able to accumulate. 2.2.3

Acceptance of the Criterium "Persistence"

The criterium Persistence has been accepted very reluctantly by the scientific community and politicians. It is surprising, since evidently many organic environmental chemicals of concern ("Xenobiotica") are persistent to different degrees. One reason for this reluctancy in accepting the obvious seems to be the fact that most persistent chemicals are also very inert in the technosphere. This makes them useful for many applications where high stability against heat, light etc. is required. The acute toxicity of many persistent chemicals is low, so that these substances often have been considered as wholly inert and - in a non-permissible generalization safe to the environment. The other main reason seems to originate from a deeply rooted unwillingness to accept our ignorance about basic ecological functions and how trace amounts of chemicals could influence them. Recognizing this ignorance, however, ESVR-Environ. Sci. & Pollut. Res. 1 (2)

1994

and taking into account the possibility of new findings about the ecotoxicity of substances is the key of the second argument put forward in Section 2.2.2. Taking Persistence as the main criterium of environmental hazard assessment (but not the only one) does not and cannot fulfil the often stated, unrealistic demand for "ZeroRisk". However, the implementation of degradability makes reversible such damages which cannot be avoided even after careful testing recording the the state of the art. The criterium Persistence is fully in accordance with POPVER'Sphilosophy, especially with the principles expressed in his famous book "The Open Society and Its Enemies" [26]. POPVERconcludes that it is less important to have ideal (political) leaders, as demanded by Plato and his epigones, but very important to have mechanism to remove them from power if they turn out to be incompetent or criminal. In philosophy it took more than 2000 years to gain this insight. Hopefully, in environmental policy it will not take as long to draw the analogous conclusion with regard to chemicals.

3 3.1

Examples of Persistent Chemicals Polychlorinated Biphenyls (PCB)

The PCB have similar properties as the persistent substances DDT and HCB: they are very sparingly soluble in water, lipophilic [28] and hardly degradable. They consist of 209 individual compounds derived from biphenyl by different degrees of substitution of the 10 H-atoms of the parent compound by chlorine atoms. According to these properties, introduction into the environment leads unavoidably to accumulation in sediments, especially those with a high content in organic matter accumulation in animals living in contaminated water or sediment and in predators eating these animals (e.g. sea birds) - entry into the food chain and, hence contamination of man (fat tissues, milk). -

-

-

These considerations show the importance of physicalchemical parameters together with more biological ones for explaining the behaviour of this group of substances. SHIO and MACKAY [28] showed that the behaviour described is not only valid for the higher chlorinated members. The dimensionless Henry-coefficient (which describes the distribution between air and water) is about the same for all members (H ~ 0.01); an approximate estimate of volatility indicates a partial transfer from water to air [13,20], the highly lipophilic compounds tend, however, to be attached physically to the humic substances of waters if the dissolved organic matter is higher than about 1 mg/L [30]. Hence, PCB may enter into the atmosphere and be transported there over long distances, as well as into the sediments. The view that PCB is partly adsorbed to suspended particles has been confirmed experimentally [31]. The highest concentrations measured in German river sediments are in the order of several mg/kg dry matter [32], in the sediments of the Hudson river (USA) up to 1000 mg/kg in so called "hot spots" [33].

111

Chemicals Regulation Assessment In fish, concentrations up to 4 mg/kg total weight were measured [34]. The concentrations of PCB in the environmental media are higher now than those of the "classical" persistent pollutants as DDT and HCB. A significant decrease of these concentrations cannot be expected in the near future due to a giant "depot" in the technosphere, consisting of transformer oils, hydraulic oils (used in mining) etc.. Open uses of PCB, e.g. as plastizisers, were forbidden already in the 70's [36]. However, even from the time before the ban, residual PCB is still around. These older residues are distinguished from the newer ones: 1) In older products, higher chlorinated fractions were used which are especially persistent 2) Some PCB-compounds were degraded, depending on their substitution pattern, more easily than others [37].

Review Articles MOLINA [75], supported by detailed, albeit preliminary calculations [24] and tropospheric concentrations measured by LOVELOO([78]. These results were reviewed soon after the original publication by contract of UBA, Berlin [45] with the result that the assumptions of the hypothesis by ROWLAND and MOLINA is correct, but that the numerical estimates were not accurate enough to predict the future development of the ozone layer. This judgement did hold for about 10 years. The measured tropospheric concentrations increased in accordance with the assumption that there is no sink in the troposphere. Due to the very long chemical lifetime in the troposphere, the CFC can pass through the tropopause and enter the stratosphere, as predicted by ROWLAND and MOLINA.

The PCB depot has to be removed as completely and carefully as possible. The problem of substitution products [35,38 - 41] arising will be treated in Part III in more detail. Here, it should only be mentioned that the Silicones (Polydimethyl-siloxanes [52], proposed as substitutes for some uses of PCB, have already been detected in sediments and sewage sludges [27, 42]. The question of the degree of persistence of the Silicones is still a matter of controversy [43] but deserves a closer investigation. Their accumulation in fish seems to be low [44,60], due to the relatively high molar mass.

The observation of the yearly "ozone hole" over the Antarctis [47] brought a new, dramatic development. This observation showed for the first time measurable effects of the CFC and similar persistent halogen-compounds. This discovery increased the speed of the political discussion, which had already started in the 70's, in America and in Europe. At the 2nd International Conference on Fluorochlorohydrocarbons in Munich, December 1978 [48], all essential facts were known, except the ozon-hole and its genesis. In recent years, an Enqu&e-Commission of the German Parliament (Bundestag) collected all relevant information and made suggestions for the future environmental policy with regard to atmospheric pollutants of global climatic relevance [84].

3.2

In connection with the discussion on persistence and degradability, four issues seem to be especially relevant:

Chlorofluorohydrocarbons (CFC)

The most important CFC are trichlorofluoromethane (CFC 11) and dichlorodifluoromethane (CFC 12). These compounds and similar CFC have been used until recently as propellants/solvents in spray systems; their use in the production of insulating foams, as refrigerants and special solvents will phase out in the near future [6,24,25]. The very high vapour pressure, low water solubility, and low adsorption potential of these substances lead to the emission during and after use of CFC into the troposphere (the lower 10 to 15 km of the atmosphere). There is no sink for the CFC in the troposphere since they do not react measurably with OH, 03 and NO 3 or in a direct photochemical reaction (in contrast to the stratosphere where short wavelengths, i.e. high energy UV-radiation is available). The upper limit of the bimolecular rate constant for the OH-reaction amounts to about [46] ko~ (CFC 11,12) _ 10 17 cm3/molecule 9 s For the (tropospheric) chemical lifetime ro~ , related to the OH-reaction, a lower limit of 1

~'oH (CFC 11,12) >_ ko H < [OH] > >__ 2 9 1011 s >_- 6000 a is calculated, using the average OH-concentration < [OH] > = 5 9 10 s radicals cm 3 [83]. The hypothesis of chlorine-catalysed destruction of the stratospheric ozone was first put forward by ROWLAND and

112

1) The CFC 11 and 12 have excellent technical properties due to their chemical inertness, stability and very low toxicity [6,23]. 2) The environmental hazard detected by ROWLAND and MOLtNA [24,75,84], which implies that life on earth is seriously threatened by the continuing emissions of CFC could not have been known at the time of CFC development and commercialization by industry (about 1950). 3) The complex (heterogeneous) reactions leading to the yearly formation of the antarctic ozone-hole [47] are related to the (homogeneous) reactions predicted by ROWLANDand MOLINA,but not identical with them. This means that the discovery of the ozone-hole was a surprise even to the advocates of the ozone depletion hypothesis. 4) The contribution of CFC to the greenhouse effect was predicted by RAMANATHAN[76] soon after publication of the ozone hypothesis but could also not be known at all in the early 50's. As a result of these facts, it is clearly evident that the only property of CFC 11 and 12 known at the time of introducing the CFC into the market, which could have been recognized as a warning signal, is their extreme chemical and physical stability. None of the global hazardous effects (homogeneous ozone depletion, ozone-hole formation, and greenhouse effect) would have been predicted on the basis of toxicity and ecotoxicity testing, not even at the highest level of model ecosystems. All ecotoxicological testing results would have led to the conclusion that CFC 11 and 12 are completely harmless to the environment. ESPR-Environ. Sci. & Pollut. Res. 1 (2) 1994

Review Articles After the international treaties of Vienna and Montreal, substitution products for CFC have become a necessity [ 4 8 - 51,53]. This problem will be discussed in Part III in more detail. Here, in discussing persistence as an environmental hazard criterium, a serious warning against fully fluorinated compounds (FC) as potential substitutes for some CFC uses is appropriate. These compounds, although not carrying chlorine atoms into the stratosphere, are even more persistent than the CFC [77]. Since we do not know enough about reactions of F-atoms in the higher layers of the stratosphere, the use of FC would mean repeating the same error as with the CFC around 1950. In the formulation given by RAVISHANKARAet al. [77]: "If released into the atmosphere, these molecules (i.e. FC) will accumulate and their effects will persist for centuries or millenia". 3.3

Di(2-ethylphthalate) (DEHP)

DEHP is produced globally at about 1 to 4 Mio t / y r [13,54,55], the upper limit being more realistic, since 2 Mio t / y r are estimated for the USA alone [54,56]. DEHP is mostly used as a plastiziser for PVC and a few other plastics; it enters the environment during the production of DEHP, production of PVC articles, and the use and incorrect waste removal of DEHP-containing products. The total amount of DEHP entering the environment has been estimated to be about 100 000 t/yr. The physical-chemical properties of DEHP (low solubility in water, low vapour pressure, and small Henry-coefficient) show that DEHP tends toward the environmental compartments soil and sediment. Indeed, in contaminated sediments up to 70 [13] or 1400 mg/kg [54] have been measured. The typical concentration in less heavily contaminated sediments amounts to 0.001 to 1 mg/kg [13]. The strong accumulation is well predicted by the octanol-water partition coefficient (log Pow = 4.9 [13]). Bioaccumulation is observed in fish, but stronger in crabs and molluscs [13]. The occurrence of DEHP in many water (even deep-sea) animals is well documented [56]. Due to its ubiquitous occurrence DEHP is considered to be a persistent compound, although some sinks are known and at least partial degradation in sewage treatment plants has been reported [13,54,55,59]. It seems to be certain that DEHP can be degraded biocbemically in an aerobic, strongly temperature-dependent reaction so that no degradation occurs below 5 ~ [54]. DEHP is not degraded anaerobically and consequently is protected in anoxic sediments as in the case of PAH. Abiotic degradation is effected by hydrolysis; the rate constants reported [13,55,57,58], however, vary over many orders of magnitude, yielding hydrolytic half-lives in the range from 16 days to > 100 years. The paradox of DEHP persistence mentioned by W.ZMS [55] and LaRSSON [54] consists in the apparent contradiction between ubiquitous occurrence on the one hand, and the existence of sinks which can be reached in the environment on the other. This paradox can possibly be resolved by the

ESVR-Environ. Sci. & PoUut. Res. 1 (2) 1994

Chemicals Regulation Assessment

assumption that (biological as well as abiotic) degradation in water is slow, so that adsorption on dispersed particles can occur, followed by the sinking of the particles charged with DEHP and similar compounds to the sediments. This process is clearly favoured by low temperatures (very slow degradation and increased adsorption). DEHP shows little acute toxicity toward mammals [13,56]. It hinders the microbial metabolism in sediments above 25 mg/kg [54]. Further toxic effects have been reviewed by THOMAS et al. [56] and in the BUA-Report No. 4 [59]. DEHP was declared as "Priority Pollutant" in the USA and in the Netherlands. The question of the efficiency of the sinks should be clarified. Furthermore, DEHP is another good example for the formation of huge depots within the technosphere [6]. Similar cases are PCB in transformers (Section 3.1) and CFC in closed-pore foamed plastics and in cooling systems (Section 3.2). In the case of DEHP, the depot consists mainly of high amounts of soft PVC which contains up to 40 % DEHP. It was estimated [6] that this depot amounted to 10 - 20 Mio t DEHP at the end of the 70's and could increase to about 100 Mio t DEHP at the beginning of the next century. If in the future further adverse effects of DEHP were detected, this depot will have to be carefully collected and destroyed, as now in the case of PCB. In contrast to the environment, this is possible in the technosphere, at least in principle, but it is costly and can never be done without some leaking into the environment. 3.4

2,3,7,8-Tetrachlorodibenzodioxin (TCDD)

TCDD is the only example discussed here which has never been produced as such commercially, except in very small quantities for scientific purposes; it is formed together with compounds of similar chemical composition, the polychlorinated dibenzodioxins (PCDD) and dibenzofurans (PCDF) during incomplete burning or after the actual flame reactions ("de novo synthesis"), during pyrolysis of chlorinated precursors [ 6 1 - 63], from waste incineration, car traffic [61,64,65] and other sources. TCDD is furthermore a coproduct in the production of 2,4,5-trichlorophenol and was found as an impurity in this substance and in 2,4,5-trichlorophenoxyacetic acid (2,4,5-T). The physical-chemical properties of TCDD [13,66,67] are similar to those of other lipophilic, polychlorinated Xenobiotics. Since it is furthermore very slowly degraded, it accumulates in fat-tissues of animals, milk-fat and other non-polar media. Due to the small amounts formed (ca. 1 kg/yr in Germany), the concentrations measured are in the realm of a few ng/kg soil, sediment or fat tissue [13,61]. The uptake of TCDD (as well as PCDD/PCDF) by man is mainly via the food [67]. In assessing the TCDD burden, the extreme toxicity of this substance has to be taken into account [61,63,68]. TCDD seems to be the most toxic anthropogenic compound as can be seen from the lowest lethal dosis of about 1/ag/kg for the most sensitive mammal. This toxicity is surpassed by some bacterial toxins by several orders of magnitude [61,62].

113

Chemicals Regulation Assessment T C D D has a special place among the environmental pollutants: T C D D combines the typical properties of a xenobiotic compound, especially persistence and accumulation, with those of a very strong poison showing a broad spectrum of effects. This combination of properties is rare and caused a dramatic publicity of the T C D D problem (e.g. [69 - 7 1 ] ) . The toxic effects alone would not have been sufficient to make T C D D the "Pollutant No. 1". It is the very slow degradation which enables long range distribution, entering the food chain, and long term contamination of sobs. According to conservative estimates [68], the acceptable daffy intake (ADI) of about 1 - 5 pg T C D D / k g has not yet been reached [67]. For the average US-citizen, the actual daily intake is estimated to be about 0 . 6 - 0 . 7 pg kg I d -1. The average concentrations measured in mother's milk amount to about 1000 p g / L [13,61,72,81,82]. This value includes the contributions by other highly toxic members of the PCDD/PCDF group ("toxic TCDD-equivalents"). The highest European contaminations of T C D D alone amount to 10 p g / g (ptt) based on the fat content of the human milk, the average value being lower by a factor of 2 to 3 [82]. Taking the above value of 1000 pg toxic TCCD-equivalents per L human milk yields a daily intake of about 150 pg kg 1 d ~ [72] for a 5 - 6 months old child, i.e. 30 to 150 times the ADI value. In the ADI value, which is calculated for livelong exposure, safety factors of 100 to 5000 are included [72], depending on the mode of calculation. This means that surpassing this value does not necessarily present an acute hazard. Furthermore, man seems fortunately not to belong to the most sensitive targets of TCDD. Nevertheless it has to be pointed out that the babies are not only a group of the population which is especially worth of protection against toxic compounds, but also may be more vulnerable than the adult population. For this reason, as well as for many open questions in the formation and environmental behaviour of T C C D , PCDD and PCDF [79,80], priority should be given to ecotoxicity research and prevention of dioxin pollution from all sources.

4

Conclusions

The arguments put forward and illustrated with some prominent examples lead to the following conclusions: 1) Degradability - favourably mineralization - has to be demanded for all chemicals which enter the environment during production, use and waste removal and are thus withdrawn from the control by man. 2) Persistence is - albeit not the only - the central criterinm of environmental hazard assessment of anthropogenic, organic chemicals. 3) The combination of persistence with accumulation leads to high concentrations in certain areas of the environment or in certain tissues of animals and man (examples: PCB, DEHP) 4) The combination of persistence with very high toxicity leads to the most dangerous environmental toxins (example: TCDD).

114

Review Articles 5) The absence of any significant toxicity does not exclude at all that global environmental damages of unthinkable dimensions may be caused by persistent and mobile compounds (examples: CFC). The quantification of persistence, which was only marginally addressed in this work, was theoretically treated in [19]. If there are only few sinks in one preferred compartment, persistence can be defined as the reciprocal sum of all degradation rate constants of 1st order. In this quantification, persistence has the dimension of time ("chemical lifetime" r). This approach is more easy for abiotic sinks than for biochemical ones and for the media air and water more easy than for soil and sediment. In the more general case of multimedia distribution, the hypothetical decrease of the total amount after dosing the input into the environment could serve as a measure of persistence. The time used to reach 50 % (tl/2) or 37 % (r) of the original amount would have to be calculated from measured transfer and degradation data. It has been tentatively suggested [6] that a substance should be called "persistent" if this multimedia halflife was greater than one year. No simple exponential decay can be expected, however. More work seems to be necessary for environmental exposure analysis, as a prerequisite for a better quantification of persistence and of a better understanding of the fate of chemicals in the environment.

5

Literature

ll1 KLOPFFER,W.: Environmental Hazard Assessment of Chemicals and Products. Part L General AssessmentPrinciples. Environ. Sci. & Pollut. Res. International 1 (1) (1994) 47-53 [2] KLOI'FFER,W.: Persistenz und Abbaubarkeit in der Beurteilung des Umweltverhaltens anthropogener Chemikalien. UWSF-Z. Umweltchem. C)kotox. I Nr. 2 (1989) 43-51 [3] FRICK,G.W. (Ed.): Environmental Glossary. 2nd Edition. Government. Institutes, Inc., Rockville (MD), USA 1982 [4] Council Directive79/831/EEC Amending for the Sixth Time Directive 67/548/EEC on the Classification, Packaging and Labelling of Dangerous Substances. Off. J. L 259/10 15 October 1979 [5] CAIRNS,J., Jr.: Politics, Economics, Science - Going Beyond Disciplinary Boundaries to Protect Aquatic Ecosystems.In: EVANS, M.S. (Ed.): Toxic Contaminants an Ecosystem Health, A Great Lakes Focus. John Wiley and Sons, New York 1988 [6] FRISCHE, R.; KLOPFFER,W.; SCHONBORN,W.: Bewertung von organisch-chemischen Stoffen und Produkten in Bezug auf ihr Umweltverhalten - chemische, biologische und wirtschaftliche Aspekte, 1. und 2. TeiL Bericht des Battelle-Institutse.V., Frankfurt am Main, an das Umweltbundesamt, Berlin, Forschungsbericht 101 04 009/03 (1979) [7] FRISCHE,R.; ESSER,G.; SCHONBORN,W.; KLOPrrER,W.: Criteria for Assessing the Environmental Behavior of Chemicals: Selection and Preliminary Quantification. Ecotoxicol. Environ. Safety 6 (1982) 283-293 [8] HARTgOVr,G; BOHNE,E.: Umweltpolitik. Bd. 1. Westdeutscher Verlag, Opladen (1983) [9] BOGAN,R.H.; SAWYrR,C.N.: Biochemical Degradation of Synthetic Detergents. I. Preliminary Studies. Sewage Ind. Wastes 26 (1954) 1069 - 1080 [10] STUMM,W.: Die Beeintriichtigung aquatischer Okosysteme durch die Zivilisation. Naturwiss. 64 (1977) 157-165 ESPR-Environ. Sci. & PoUut. Res. 1 (2) 1994

Review Articles

[11] BOGAN,R.H.; SAWYER,C.N.: Biochemical Degradation of Synthetic Detergents. II. Studies on the Relation Between Chemical Structure and Biochemical Oxidation. Sewage Ind. Wastes 27 (1955) 917 - 928 [12] Dn(SHITH,T.S.S.: DDT - The Problem of Residue and Hazard. J. Scient. Ind. Res. 37 (1978) 316-328 [13] RIPPEN, G.: Handbuch Umweltchemikalien. Stoffdaten - Priifverfahren - Vorschriften. Landsberg: ecomed, Loseblattsammlung, Stand 1993 [14] BOGAN,R.H.;SAWYER,C.N.: Biochemical Degradation of Synthetic Detergents. III. Relationship Between Biological Degradation and Froth Persistence. Sewage Ind. Wastes 27 (1956) 637-643 [15] RIPPEN, G.; FRANK, R.: Estimation of Hexachlorobenzene Pathways from the Technosphere into the Environment. In: MORRIS, C.R.; C ~ I . , J.R.P. (Eds.): Hexachlorobenzene. Proceedings of an Int. Symposium. IARC Sci. Publications No. 77 (1986) 4 5 - 5 2 [16] KORTE, F.; BAHADIR,M.; KLEIN, W.; LAY, J.P.; PA~AR, H.: Lehrbuch dee Okologischen Chemie. Thieme, Stuttgart (1987) [17] KORTE, F.: Absch/itzungsm6glichkeiten zukfinftiger Umweltbelastungen durch organische Verbindungen. In: AURAND, K.; FL~SELBARTH, H.; L~qMANN, E.; MOLLER, G.; NIEMITZ, W. (Hrsg.): Organische Verbindungen in der Umwelt. E. Schmidt Verlag, Berlin (1978) 288- 298 [18] STEeHENSON,M.S.: An Approach to the Identification of Organic Compounds Hazardous to the Environment and Human Health. Ecotoxicol. Environ. Safety 1 (1977) 3 9 - 4 8 [19] KLOPrrrR,W.; RIePEN,G.; FRISCHE,R.: Physicochemical Properties as Useful Tools for Predicting the Environmental Fate of Organic Chemicals. Ecotoxicol. Environ. Safety6 (1982) 294 - 301 [20] KLOPFFER,W.; KAUFMANN,G.; R1PPEN,G.; POREMSKI,H.-J.: A Laboratory Method for Testing the Volatility from Aqueous Solution: First Results and Comparison with Theory. Ecotoxicol. Environ. Safety 6 (1982) 545- 559 [21] Crnov, C.T.; F~ED, V.H.; SCHMEDD~qG,D.W.; KOHNERT,R.L.: Partition Coefficient and Bioaccumulation of Selected Organic Chemicals. Environ. Sci. Technol. 11 (1977)475-478 [22] GRIMMER,G.; BOHNKE,H.: Untersuchungen von Sedimentkernen des Bodensees I. Profile der polyzyldischen aromatischen Kohlenwasserstoffe. Z. Naturforsch. 32c (1977) 7 0 3 - 711 [23] HENSCHLER, D. (Hrsg.): Gesnndheitssch/idliche Arbeitsstoffe; Toxikologisch-arbeitsmedizinischeBegrfindungyon MAK-Werten. Verlag Chemie (1974) Loseblattsammlung [24] ROWLAND,F.S.; MOLINA,M.J.: Chlorofluoromethanes in the Environment. Rev. Geophys. Space Phys. 13 (1975) 1 - 3 5 [25] POPPER,K.R.: Logik der Forschung. Julius Springer, Wien 1935; 7. Auflage.: J.C.B. Mohr (Paul Siebeck), Tiibingen 1982 [26] POPPER,K.R.: Die offene Gesellschaft und ihre Feinde, Bd. 1 + 2. Francke, Bern 1957/58; 6. Auflage: Francke, UTB Nr. 472 + 473, Mfinchen 1980 [27] KLOPn:ER, W.: Origin of Anthropogenic Chemicals in Sewage Sludge. In: PILLMANN,W.; ZIRM, K. (Eds.): Proceedings of the ENVIROTECH VIENNA 1990, Hazardous Waste Management, Contaminated Sites and Industrial Risk Assessment. Wien (1990) 11-21 [28] SHIU, W.Y.; MACKAY, D.: A Critical Review of Aqueous Solubilities,Vapor Pressures, Henry's Law Constants, and OctanolWater Partition Coefficients of the Polychlorinated Biphenyls. J. Phys. Chem. Ref. Data 15 (1986) 911-929 [29] KNUDSEN,J.; BJERRE,A.: A Method of Hazard Assessment of a Gaseous Substancewith respect to Formation of Toxic Photodecomposition Products. Application to CCI4, CC13F and CCI2F2. Chemosphere 14 (1985) 249-255 [30] C~TER, C.W.; SUFFET,I.H.: Binding of DDT to Dissolved Humic Material. Environ. Sci. Technol. 16 (1982) 7 3 5 - 7 4 0 [31] BAKER,J.E.; CAPEL,P.D.; EISENREICH,S.J.: Influence of Colloids on Sediment-Water Partition Coefficients of Polychloro-biphenyl Congeners in Natural Waters. Environ. Sci. Technol. 20 (1986) 1136 - 1143

ESPR-Environ. Sci. & Pollut. Res. 1 (2) 1994

Chemicals Regulation Assessment

[32] Bundesanstalt for Gew/isserkunde (BfG): Hydrologische und 6kologische Voraussetzungen zur Umlagerung yon Baggergut in staugeregelten Bundeswasserstraflen. Sonderdruck aus dem Jahresbericht 1984, Koblenz (1985) [33] BROWN, M.P.; WERNER, M.B.; SLOaN, R.J.; SIMPSON, K.W.: Polychlorinated Biphenyls in the Hudson River. Environ. Sci. Technol. 19 (1985~ 656- 661 [34] BRU~q, M.P.; M ~ z , D.: Contamination of native fish stock by hexachlorobenzeneand polychlorobiphenylresidues. Bull. Environ. Contain. Toxicol. 28 (1987) 599- 604 [35] J~a(oBI,H.W.: Produkte mit polychloriertenBiphenylen(PCB) und mit polychlorierten Terphenylen (PCT). KUMPF,W.; MAAS, K.; STV~UB,H.; (Hrsg.): Mfill und Abfall, Bd. 5, E. Schmidt Verlag, Berlin (1985) 3 4 - 5 1 [36] 10. Verordnung zur Durchffihrung des Bundesimmissionsschutzgesetzes (Beschr~inkungvon PCB, PCT und VC) - 10. BImSchV - vom 26. Juli 1978. Bundesgesetzbl. TI. I (1978) 1138 (Bundesrepublik Deutschland) [37] BROWN,Jr., J.F.; WAGNER,R.E.; FENG,H.; BEDARD,D.L.; BRENNAN, M.J.; CARNXHAN, J.C.; MAY, R.J.: Environmental Dechlorination of PCBs. Environ. Toxicol. Chem. 6 (1987) 579 - 593 [38] LORENZ, H.; NEUMEIER, G. (Hrsg.): Polychlorierte Biphenyle (PCB), Pin gemeinsamer Bericht des Bundesgesundheitsamtesund des Umwelthundesamtes, BGA Schtiften 4/83, MMV Medizin Verlag Miinchen (1983) [39] FORST,P.; KRf)GER,C.; MEEMKEN,H.-A.; GOEBEL,W.: Gehalte des PCB-Ersatzproduktes Ugilec (Tetrachlorbenzyltoluole) in Fischen aus Gebieten mit intensivemBergbau. Z. Lebensm. Unters. Forsch. 185 (1987) 394-397 [40]RONNEFAHRT, B.: Nachweis und Bestimmung des PCBErsatzproduktes Ugilec 141 in Wasserproben und Fischen aus dee Lippe. Dtsch. Lebensmittel-Rundsch. 83 (1987) 214-218 [41] FORST,P.; KR~rGER,C.; ,~EEMKEN, H.-A.; GOEBEL,W.: Determination of the Polychlorinated Biphenyl Substitute Ugilec (Tetracblorobenzyl-toluenes) in Fish. J. Chromatogr. 405 (1987) 311-317 [42] PELLENB~RG,R.: Siliconesas Tracers for AnthropogenicAdditions to Sediments. Marine Poll. Bull. 10 (1979) 267-269 [43] FRYE, C.L.: A Cautionary Note Concerning Organosilicon Analytical Artefacts. Environ. Toxicol. Chem. 6 (1987) 329 - 330 [44] BRUGGEMAN,W.A.; WEBER-FUNG,D.; OPPERHUIZEN,A.; VANDER STEEN,J.; WIJBENGA,A.; HUTZINGER,O.: Absorption and Retention of Polydimethylsiloxanes (Silicones)in Fish: Preliminary Experiments. Toxicol. Environ. Chem. 7 (1984) 287-296 [45] HARTWIG,S.; HINTZ, R.A.; KLOPFFER,W.; SCHUSTER-WOLF,A.; ULLMANN, D.: Studie fiber die Auswirkungen yon Fluorchlorkohlenwasserstoffverbindungen anf die Ozonschicht der Stratosph~e und die m6glichenFolgen. Bericht des Battelle-lnstituts e.V., Frankfurt am Main, an das Umweltbundesamt, Berlin. LUP 411 - 112/IIIA 328. (1976) [46] ATKINSON,R.: Kinetics and Mechanisms of the Gas-Phase Reactions of the Hydroxyl Radical with Organic Compounds. J. Phys. Chem. Ref. Data Monograph 1, Am. Inst. Physics,New York 1989 [47] ZURER,P.S.: Studies on Ozone Destruction Expand Beyond Antarctic. Chem. Eng. News 66 (1988) 16-25 [48] KLOPFFER,W.; FRISCHE,R.; SCHONBORN,W.: Vergleich der Alternativen fOr R 11 und R 12 insbesondere im Hinblick auf ihre Bedeutung ffir die Umwelt. Proceedings der Internationalen Konferenz fiber Fluorchlorkohlenwasserstoffe in Mfinchen, 6 . - 8. Dezember 1978. Bd. II, (Hrsg.: Umweltbundesamt Berlin) Mercedes-Druck, Berlin-West (1979) 129- 153 [49] TAUSCHER,W.: VergleichendeBetrachtungenbei Treibmitteln und MOglichkeitendee Substitution.Seifen-Ole-Fette-Wachse113 (1987) 419 - 422 [50] H~'~DWERK,V.; ZELLNER, R.: Kinetics of the Reaction of OH Radicals with some Halocarbons (CHC1F2, CH2CIF, CH2CICF3, CH3CCIF2, CH3CHF2) in the Temperature Range 260- 370 K. Ber. Bunsenges. Phys. Chem. 82 (1978) 1161- 1166

] 15

Chemicals Regulation Assessment [51] JUNGE, C.E.: Transport Mechanism for Pesticides in the Atmosphere. Pure Appl. Chem. 42 (1975) 95 - 104 [52] SCHINDELBAUER,H.: PCB - mehr als ein Problem der Analytik. ChemZ 89 (1988) 1 8 4 - 188 [53] ZUR~R, P.S.: Search Intensifies for Alternatives to Ozone-Depleting Halocarbons. Chem. Eng. News 66 (1988) 1 7 - 2 0 [54] LARSSON,P.; THUP~N, A.; GAHNSTROM,G.: Phthalate Esters Inhibit Microbial Acitivity in Aquatic Sediments. Environ. Polut. (Series A) 42 (1986) 2 2 3 - 231 [55] WAMS, T.J.: Diethylhexytphthalate as an Environmental Contaminant - A Review. Sci. Total Environ. 66 (1987) 1 - 16 [56] THOMAS,J.A.; DARBY,T.D.; WALLn%R.F.; GARVlN,P.J.; MARIS, L.: A Review of the Biological Effects of Di-(2-ethylhexyl)phthalate. J. Toxicol. Appl. Pharmacol. 45 (1978) 1 - 27 [57] TURNER, L. (Ed.): An assessment of the occurrence and effects of dialkyl ortho-phthalates in the environment. European Chemical Industry Ecology & Toxicology Centre ECETOC, Brussels (1985) [58] THINIUS, K.: Stabilisierung mad Alterung yon Plastwerkstoffen, Bd. 2. Akademie-Verlag, Berlin (1971) [59] Beratergremium fiir umweltrelevante Altstoffe (BUA) der Gesellschaft Deutscher Chemiker (Hrsg.): Di-(2-ethylhexyl) phthalat. BUA-Stoffbericht 4. VCH Verlagsges., Weinheim (1986) [60] OPPERHUtZEN,A.; DAMEN,H.W.J.; ASYEE,G.M.; VANDERSTEEN, J.M.D.; HUTZINGER, 0 . : Uptake and Elimination by Fish of Polydimethylsiloxanes (Silicones) after Dietary and Aqueous Exposure. Toxicol. Environ. Chem. 13 (1987) 2 6 5 - 2 8 5 [61] Umwettbundesamt (Hrsg.): Sachstand Dioxine - Stand November 1984 - . Berichte 5/85 E. Schmidt Verlag, Berlin (1985) [62] Verband der Chemischen Industrie, e.V. (Hrsg.): Dioxin in der Umwelt. VCI Schriftenreihe Chemie + Fortschritt, Frankfurt am Main, 1 (1985) [63] HUTZINGER,0.; Fn~x, M.; THOMA, H.: PCDD und PCDF: Gefahr f/ir Mensch mad Umwelt? Chemie in unserer Zeit 20 (1986) 165 - 170 [64] RAPPE, C.; ANDERSSON, R.; BERGQIST, P.-A.; BROHEDE, C.; HANSSON, M.; KJELLER,L.-O.; LINDSTROM,G.; MARKLUND,S.; NYGREN, M.; SWANSON,S.E.; TYSKI.IND,M.; WIBERG,K.: Sources and Relative Importance of PCDD and PCDF Emissions. Waste Management ges. 5 (1987) 225 - 237 [65] MARKLUND,S.; RAPPE, C.; TYSKLIND,M.; EGEB,~CK,K.-E.: Identification of Polychlorinated Dibenzofurans and Dioxins in Exhausts from Cars Run on Leaded Gasoline. Chemosphere 16 (1987) 2 9 - 36 [66] SHIU, W.Y.; DONCELE, W.; GOBAY, F.A.P.C.; ANDP,EN, A.; MACKAY,D.: Physical-chemical properties of chlorinated dibenzop-dioxins. Env. Sci. Technol. 22 (1988) 6 5 1 - 658 [67] T~,AVlS, C.C.; HATTEMER-FREY, H.A.: Human Exposure to 2,3,7,8-TCDD. Chemosphere 16 (1987) 2331 - 2342 [68] AHLBORG,U.G.; VXCTORIN,K.: Impact on Health of Chlorinated Dioxins and Other Trace Organic Emissions. Waste Management & Res. 5 (1987) 2 0 3 - 224 [69] HUTZINGER, O.; CRUMMET, W.; KARASEK,F.W.; MERIAN, E.; REGGLANI, G.; REISS~GER, M.; SAFE, S. (Eds.): Chlorinated 2nd European Conference "Environment Heisinki, June 20 - 22, 1994

and

Health"

Provisional Programme

Monday, 20 June 1994 Theme 1: The road to Helsinki 11:00-13:00 Session 1: Global and European developments Introductory presentations: - Agenda 21 - WHO's global environmental health strategy - Environment for Europe process - WHO's regional environmental health programme Statements/discussions by Ministers Theme 2: Environmental health in the new Europe Session 1: Concern for Europe's Tomorrow 14.30 - 16.00 Introductory presentation: - Assessment of the environmental health situation in Europe Statements/discussions by Ministers Session 2: Urban health challenges 16.30 - 18.00 Panel Statements/discussions by Ministers Tuesday, 21 June 1994 Theme 2: Environmental health in the new Europe 09.00 - 10.30 Session 3: The lessons of Chernobyl

116

2nd European Conference Dioxins and Related Compounds 1985. Proceedings of the 5th Int. Symp. held at Bayreuth, Germany 16 - 19 Sept. 1985. Chemosphere 15 (1986) Nos 9 - 1 2 (1986) [70] MASUDA, Y.; HUTZINGER, O.; KARASEK,F.W.; NAGAYAMA,J.; RAPPE, C.; SAFE, S.; YOSHIMURA,H. (Eds.): Chlorinated Dioxins and Related Compounds 1986. Proceedings of the Sixth Int. Symp. heir at Fukuoka, Japan, 16 - 19 Sept. 1986 Chemosphere 16 (1987) Nos. 8 - 9 [71] Verein Deutscher Ingenieure (Hrsg.): VDI Berichte 634, Dioxin. Eine technische, analytische, 6kologische und toxikologische Herausforderung. KoUoquium Mannheim, 5. bis 7. Mai 1987. VDI Verlag, Dfisseldorf (1987) [72] HUTZINGER, 0 . : Dioxine - Okochemie, Expositions- und Risikoanalyse, Grenzwertermitttung. In: Verhand der Chemischen Industrie, e.V. (Hrsg.): Dioxin in der Umwelt. VCI Schriftenreihe C h e m i e + Fortschritt, Frankfurt am Main, 1 (1985) 2 6 - 34 [73] GIGER, W.; CONRAD, T.: Phosphatersatzstuffe in Waschmitteln und ihre Umweltvertr/iglichkeit. Wasser Berlin '85. Wissensch. Verlag Spiess, Berlin (1985) 3 6 2 - 377 [74] JUNGE, C.R.: Transport Mechanism for Pesticides in the Atmosphere. Pure Appl. Chem. 42 (1975) 9 5 - 1 0 4 [75]MoLINA, M.J.; ROWLAND, F.S.: Stratospheric sink for chlorofluoro-methanes: Chlorine atom catalyzed destruction of ozone. Nature 249 (1974) 8 1 0 - 814 [76] RAMANATHAN,V.: Greenhouse Effect Due to Chlorofluorocarbons: Climatic Implications. Science 190 (1975) 5 0 - 5 2 [77] RAVISHANKAKA,A.R.; SOLOMON,S.; TUKNlPSEED,A.A.; WAP,~N, R.F.: Atmospheric Lifetimes of Long-Lived Halogenated Species. Science 259 (1993) 194 - 199 [78] LOVELOCK, J.E.; MAGGS, R.J.; WADE, R.J.: Halogenated Hydrocarbons in and over the Atlantic. Nature 241 (1973) 194 - 196 [79] RIPPEN, G.; GIHR, R.; RENNER, I.; KLOPFFER,W.: Belastung yon B6den durch Abfallverbrennung, Kraftfahrzeugyerkehr, landwirtschaftliche Nutzung, Kleinfeuerungsanlagen und photochemische Prozesse. UWSF-Z. Umweltchemie Okotox. 4 (1992) 3 0 - 3 5 [80] GIHR, R.; KLOPFFER,W.; RIPPEN, G.; PARTSCHT,H.; SIOLL, U.; MOLLEP.,J.: Investigations on Potential Sources of Polychlorinated Dibenzo-p-dioxins an Dibenzofurans in Sewage Sludges. Chemosphere 23 (I991) 1653 - 1659 [81] FOP.ST, P.; FORST, Chr.; W1LMERS, K.: PCDDs and PCDFs in Human Milk - Statistical Evaluation of a 6-Years Survey. Chemosphere 25 (1992) 1 0 2 9 - 1038 [82] YRJANHEIKKI,E.J.: Levels in Human Milk: Health Risks for Infants. In.: Health Effects an Safety Assessment of Dioxins and Furans. Workshop Report, Karlsruhe, January 1 5 - 1 7 , (1990) 500-505

[83] WAmqECK, P.: Chemistry of the natural atmosphere. Intern. Geophysics Series. New York (1988) [84] Enquete-Kommission ,Schutz der Erdatmosph~ire" des 12. Deutschen Bundestages: KlimaSnderung gefShrdet globale Entwick,lung. Zukunft sichern - Jetzt handeln. Economia Verlag, Bonn; Verlag C.F. Mtiller, Karlsruhe 1992 Panel Statements/discussions by Ministers Session 4: Armed conflict and environmental health Panel Statements/discussions by Ministers Session S: Environmental health in countries of central and eastern Europe and newly independent

11.00-12.30 14.30 - 16.00

states

Panel Statements/discussions by Ministers Session 6: Accidents Panel Statements/discussions by Ministers Wednesday, 22 June 1994 Theme 3: The way forward in partnership Session 1: Implementation of environmental health action plan - challenges for governments and intergovernmental and nongovernmental organizations Panel Statements/discussinns by Ministers Session 2: Adoption of the Helsinki Declaration on Action for Environment and Health in Europe

16.30-18.00

09.00 - 10.30

11.00 - 12.30

ESPR-Environ. Sci. & Pollut. Res. 1 (2) 1994