Environ Sci Pollut Res (2015) 22:6789–6799 DOI 10.1007/s11356-014-3869-5
RESEARCH ARTICLE
Levels of major and trace elements, including rare earth elements, and 238U in Croatian tap waters Željka Fiket & Martina Rožmarić & Matea Krmpotić & Ljudmila Benedik
Received: 25 July 2014 / Accepted: 16 November 2014 / Published online: 29 November 2014 # Springer-Verlag Berlin Heidelberg 2014
Abstract Concentrations of 46 elements, including major, trace, and rare earth elements, and 238U in Croatian tap waters were investigated. Selected sampling locations include tap waters from various hydrogeological regions, i.e., different types of aquifers, providing insight into the range of concentrations of studied elements and 238U activity concentrations in Croatian tap waters. Obtained concentrations were compared with the Croatian maximum contaminant levels for trace elements in water intended for human consumption, as well as WHO and EPA drinking water standards. Concentrations in all analyzed tap waters were found in accordance with Croatian regulations, except tap water from Šibenik in which manganese in concentration above maximum permissible concentration (MPC) was measured. Furthermore, in tap water from Osijek, levels of arsenic exceeded the WHO guidelines and EPA regulations. In general, investigated tap waters were found to vary considerably in concentrations of studied elements, including 238U activity concentrations. Causes of variability were further explored using statistical methods. Composition of studied tap waters was found to be predominately influenced by hydrogeological characteristics of the aquifer, at regional and local level, the existing redox conditions, and the household plumbing system. Rare earth element data, including abundances and fractionation patterns, Responsible editor: Philippe Garrigues Ž. Fiket (*) : M. Rožmarić : M. Krmpotić Division for Marine and Environmental Research, Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia e-mail: [email protected] Ž. Fiket : M. Rožmarić Environment Laboratories, International Atomic Energy Agency, 4 Quai Antoine 1er, 98000 Monaco, Monaco L. Benedik Department of Environmental Sciences, Jožef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia
complemented the characterization and facilitated the interpretation of factors affecting the composition of the analyzed tap waters. Keywords Geochemistry . Trace elements . Rare earth elements . 238-U . Tap water . Croatia
Introduction Croatia is a country rich in water with a relatively high quality of surface water and groundwater. The largest part of the Croatian population for all daily needs uses public water supply. It is estimated that the population not connected to the public water supply (24 % of the population) uses less than 10 % of the total annual volume of water abstracted for public and industrial use (excluding hydropower). The need for public water supply relies mostly on groundwater (90 %), while the remaining 10 % is surface water. On the Croatian territory, two main types of aquifers can be distinguished: intergranular prevailing in the northern and eastern part, the Pannonian basin, and karstic with secondary fracture porosity in the western part, the area of the Dinarides. The geological setting strongly influences the occurrence of dissolved trace elements (Johannesson et al. 2000; Janssen and Verweij 2003; Guo et al. 2010) and natural radionuclides in groundwater (Chabaux et al. 2008; Porcelli 2008). Their concentrations are variable and depend on the nature of the aquifer rock types and the prevailing lithology as well as on the movement dynamics through aquifers. Numerous factors have an influence on trace element and uranium concentration in natural water, such as type of the aquifer, redox conditions, acidity/alkalinity, CO2 and O2 concentration, temperature, and presence of inorganic and organic compounds, colloids (Chabaux et al. 2008; Porcelli 2008). On the other hand, the increased levels of trace elements and radioactivity in natural
6790
waters could be the result of the past or current anthropogenic activities, including practices due to activities producing technologically enhanced naturally occurring radioactive material (TENORM) sources, like mining and phosphate industry (Chalupnik et al. 2001; Perianez 2005), or increased use of phosphate fertilizers (Skoulikidis et al. 2006). To avoid potential health hazard caused by elevated concentrations of trace elements in drinking water and to ensure that drinking water does not represent any significant risk to health over a lifetime of consumption, guidelines have been set by many authorities. Maximum acceptable concentrations of potentially toxic trace elements in drinking water have been proposed by World Health Organization (WHO) in Guidelines for Drinking Water Quality (Table 1) (WHO 2011). These guidelines are not mandatory limits but are intended to be used as recommendations for setting national standards. The European Union (EU) has passed standards for trace element levels in drinking water (EU Directive 1980/778/EEC 1980; EU Directive 1998/83/EC 1998; EU Directive 2003/40/EC 2003), and recently for radioactivity in drinking water (EU Directive 2013/51/EURATOM), as well as the Environmental Protection Agency (EPA 2012). New Directive 2013/51/ EURATOM (2013) issued by European Community lays down requirements for the protection of the health of the general public with regard to radioactive substances in water intended for human consumption where requirements for parameters of radionuclides to be monitored in water are defined. On the other hand, uranium is also known as a toxic trace metal, and its intake by water should be limited by consideration of its toxicity to the kidneys (Wrenn et al. 1985). Standards are set to ensure drinking water quality based on the latest scientific evidence as well as to secure an efficient and effective monitoring and assessment of drinking water quality. They are proposed and revised by the authorities on a regular basis. Croatia has also set the regulations for maximum permissible concentrations (MPCs) of some elements in drinking water (Table 1). However, legislation in Croatia (NN 56/2013 2013; NN 125/2013 2013) allows higher standard for arsenic in some areas, because of the specific regional lithology and outdated water supply system, which determines higher background value for this harmful element. However, the regulations define the MPC of only a few elements (Table 1), and many trace elements are usually not analyzed. For a better assessment of the quality of drinking water ,there is a need for indications on their concentrations and ranges of variation. Therefore, in this research, in addition to the elements specified in the regulations, additional major and trace elements were analyzed, including the group of rare earth elements (REEs). Their mobility is generally very low, so their concentrations in drinking water are in the order of ng L−1. However, natural or human origins may lead to elevated levels of REEs in groundwater. For instance, weathering processes, enhanced by deposition of acid rains,
Environ Sci Pollut Res (2015) 22:6789–6799 Table 1 Maximum contaminant level for trace elements in drinking water, expressed as μg L−1 or mg L−1, permitted by Croatian, WHO, and EPA regulations
a
MCL allowed when existing water treatment cannot remove excessive arsenic and there is no other possibility of water supply for the population in the given area
b
Expressed in mg L−1
Element
Croatia
WHO
EPA
Ag Al As Ba Be
10 200 10 (50a) 700 –
– 200 10 700 –
100 50–200 10 2000 4
5 50 2 200 12 50 – 200 20 10 5 10 – – 5 3
3 50 2 – – 400 70 – 70 10 20 40 – 30 – 3
5 100 1 300 – 50 – – – 15 6 50 2 30 – 5
Cd Cr Cub Fe Kb Mn Mo Nab Ni Pb Sb Se Tl U V Znb
as well as the use of phosphate fertilizers (De Boer et al. 1996) could cause release of REEs to the groundwater. The importance of the determination of REEs in drinking water is associated with their possible adverse effects on human health (Rim et al. 2013, and references therein). The objectives of this study are as follows: (1) to assess the levels of trace and major elements and 238U in Croatian tap waters originating from different types of aquifers, (2) to get an overview of spatial variations in REE abundances and fractionation patterns, and (3) to determine the major processes and factors controlling the concentrations of these elements in tap waters. In this paper, the levels of the rare earth elements in drinking waters deduced from different aquifer types found on Croatian territory have been presented for the first time.
Materials and methods Hydrogeological setting Hydrogeological features of certain areas (Fig. 1) are closely associated with their geomorphological characteristics. On Croatian territory, three macro-geomorphological units can be outlined reflecting at the same time differences in the characteristics of the aquifers: the Pannonian basin, the
Environ Sci Pollut Res (2015) 22:6789–6799
6791
Fig. 1 Map of sample locations with indicated general hydrogeological characteristics of the aquifer (the dashed line represents the boundary between carbonate and non-carbonate aquifers; the color intensity of the gray scale shows the hydraulic conductivity of the aquifer; whitecolored areas are areas without significant aquifer)
Dinaridic Mountains (the Dinarides), and the Adriatic Sea depression. The northern and eastern Croatia are parts of the southern margin of the Pannonian basin dominated by the Sava and Drava river plains. The most important aquifers in this area are formed in the Quaternary sediments in the lowlands of the Sava and Drava rivers and are recharged by infiltration of precipitation and water from surface flows (Brkić et al. 2010). To the west rise the Dinarides mainly composed of Mesozoic carbonate deposits and are considered the largest continuous karst region in Europe. Numerous aquifers, very important for water supply, occur within the Dinarides, and their main characteristics are the abundance of karst geomorphological forms and deficiency in surface water (Biondić et al. 1998). Despite the fact that the Dinaridic Mountains are rich in precipitation, with up to 4000 mm a year, especially in the mountainous ranges along the Adriatic Sea coast, surface streams are rare. Overall, large area and a high quantity of precipitation result in the large abundance of groundwater. However, spatial and temporal availability of water causes problems with water supply at local level, especially in the dry season on the islands and coastal areas. Sample collection and preservation Tap water consumed in cities from various (hydro)geological regions of Croatia (the Pannonian basin in the north and east part of the country, the Dinarides and the Adriatic Sea
depression in the west and south part), with bedrock aquifers of various depths, were chosen for analysis. Sample locations of the analyzed tap waters, along with the rough hydrogeological region border, are shown in Fig. 1. The associated sample IDs are also given in Table 2. The tap water samples were collected during 2012 at consumers’ houses directly in 20-L plastic containers. Containers were previously washed with HNO3 and rinsed with the sample. To minimize precipitation and adsorption onto container walls, the samples were acidified with concentrated HNO3 to pH 2 immediately after collection according to ISO 5667–5:2006 procedure. Instruments Mulitielemental analysis of prepared samples was performed by high-resolution inductively coupled plasma mass spectrometry (HR-ICP-MS) using an Element 2 instrument (Thermo, Bremen, Germany). The measurements of the selected isotopes were performed at three different resolutions: low resolution (7Li, 9Be, 85Rb,95Mo, 109Ag, 111Cd, 120Sn, 121Sb, 133 Cs, 205Tl, 208Pb, 209Bi, 238U), medium resolution (23Na, 25 Mg, 27Al, 42Ca, 47Ti, 51 V, 52Cr, 55Mn, 56Fe,59Co, 60Ni, 63Cu, 66 Zn,86Sr, 89Y, 138Ba, 139La, 140Ce, 141Pr, 145Nd, 147Sm, 151 Eu, 157Gd, 159 Tb, 163Dy, 165Ho, 167Er, 169Tm, 171Yb, 175 Lu), and high resolution (75As, 77Se). External calibration was used for the quantification. For alpha-particle spectrometric measurements of uranium isotopes (234U and 238U), an alpha spectrometer (Alpha
6792 Table 2 Mean concentrations of elements (μg L−1) obtained for tap water (TW) samples (n=3)
Environ Sci Pollut Res (2015) 22:6789–6799
Ag Al As Ba Be Bi Ca Cd Co Cr Cs Cu Fe K Li Mg Mn Mo Na Ni Pb Rb Sb Se Sn Sr Ti Tl U V Y Zn La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu ΣREE Eu/Eu* Ce/Ce* La/Yb
TW1
TW2
TW3
TW4
TW5
TW6
TW7
TW8
0.116 44.6 30.3 109 0.021 0.002 80,730 0.019 0.144 0.406 0.087 10.5 64.1 1,560 5.76 25,410 23.8 0.49 91,380 1.22 1.61 0.850 0.042 0.030 0.029 369 0.772 0.011 0.116 0.180 0.085 37.2 0.064 0.070 0.028 0.049 0.014 0.046 0.010 0.002 0.016 0.002 0.006 0.001 0.006 0.001 0.313 17.7 0.39 1.04
0.098 26.4 0.13 47.2
RESEARCH ARTICLE
Levels of major and trace elements, including rare earth elements, and 238U in Croatian tap waters Željka Fiket & Martina Rožmarić & Matea Krmpotić & Ljudmila Benedik
Received: 25 July 2014 / Accepted: 16 November 2014 / Published online: 29 November 2014 # Springer-Verlag Berlin Heidelberg 2014
Abstract Concentrations of 46 elements, including major, trace, and rare earth elements, and 238U in Croatian tap waters were investigated. Selected sampling locations include tap waters from various hydrogeological regions, i.e., different types of aquifers, providing insight into the range of concentrations of studied elements and 238U activity concentrations in Croatian tap waters. Obtained concentrations were compared with the Croatian maximum contaminant levels for trace elements in water intended for human consumption, as well as WHO and EPA drinking water standards. Concentrations in all analyzed tap waters were found in accordance with Croatian regulations, except tap water from Šibenik in which manganese in concentration above maximum permissible concentration (MPC) was measured. Furthermore, in tap water from Osijek, levels of arsenic exceeded the WHO guidelines and EPA regulations. In general, investigated tap waters were found to vary considerably in concentrations of studied elements, including 238U activity concentrations. Causes of variability were further explored using statistical methods. Composition of studied tap waters was found to be predominately influenced by hydrogeological characteristics of the aquifer, at regional and local level, the existing redox conditions, and the household plumbing system. Rare earth element data, including abundances and fractionation patterns, Responsible editor: Philippe Garrigues Ž. Fiket (*) : M. Rožmarić : M. Krmpotić Division for Marine and Environmental Research, Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia e-mail: [email protected] Ž. Fiket : M. Rožmarić Environment Laboratories, International Atomic Energy Agency, 4 Quai Antoine 1er, 98000 Monaco, Monaco L. Benedik Department of Environmental Sciences, Jožef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia
complemented the characterization and facilitated the interpretation of factors affecting the composition of the analyzed tap waters. Keywords Geochemistry . Trace elements . Rare earth elements . 238-U . Tap water . Croatia
Introduction Croatia is a country rich in water with a relatively high quality of surface water and groundwater. The largest part of the Croatian population for all daily needs uses public water supply. It is estimated that the population not connected to the public water supply (24 % of the population) uses less than 10 % of the total annual volume of water abstracted for public and industrial use (excluding hydropower). The need for public water supply relies mostly on groundwater (90 %), while the remaining 10 % is surface water. On the Croatian territory, two main types of aquifers can be distinguished: intergranular prevailing in the northern and eastern part, the Pannonian basin, and karstic with secondary fracture porosity in the western part, the area of the Dinarides. The geological setting strongly influences the occurrence of dissolved trace elements (Johannesson et al. 2000; Janssen and Verweij 2003; Guo et al. 2010) and natural radionuclides in groundwater (Chabaux et al. 2008; Porcelli 2008). Their concentrations are variable and depend on the nature of the aquifer rock types and the prevailing lithology as well as on the movement dynamics through aquifers. Numerous factors have an influence on trace element and uranium concentration in natural water, such as type of the aquifer, redox conditions, acidity/alkalinity, CO2 and O2 concentration, temperature, and presence of inorganic and organic compounds, colloids (Chabaux et al. 2008; Porcelli 2008). On the other hand, the increased levels of trace elements and radioactivity in natural
6790
waters could be the result of the past or current anthropogenic activities, including practices due to activities producing technologically enhanced naturally occurring radioactive material (TENORM) sources, like mining and phosphate industry (Chalupnik et al. 2001; Perianez 2005), or increased use of phosphate fertilizers (Skoulikidis et al. 2006). To avoid potential health hazard caused by elevated concentrations of trace elements in drinking water and to ensure that drinking water does not represent any significant risk to health over a lifetime of consumption, guidelines have been set by many authorities. Maximum acceptable concentrations of potentially toxic trace elements in drinking water have been proposed by World Health Organization (WHO) in Guidelines for Drinking Water Quality (Table 1) (WHO 2011). These guidelines are not mandatory limits but are intended to be used as recommendations for setting national standards. The European Union (EU) has passed standards for trace element levels in drinking water (EU Directive 1980/778/EEC 1980; EU Directive 1998/83/EC 1998; EU Directive 2003/40/EC 2003), and recently for radioactivity in drinking water (EU Directive 2013/51/EURATOM), as well as the Environmental Protection Agency (EPA 2012). New Directive 2013/51/ EURATOM (2013) issued by European Community lays down requirements for the protection of the health of the general public with regard to radioactive substances in water intended for human consumption where requirements for parameters of radionuclides to be monitored in water are defined. On the other hand, uranium is also known as a toxic trace metal, and its intake by water should be limited by consideration of its toxicity to the kidneys (Wrenn et al. 1985). Standards are set to ensure drinking water quality based on the latest scientific evidence as well as to secure an efficient and effective monitoring and assessment of drinking water quality. They are proposed and revised by the authorities on a regular basis. Croatia has also set the regulations for maximum permissible concentrations (MPCs) of some elements in drinking water (Table 1). However, legislation in Croatia (NN 56/2013 2013; NN 125/2013 2013) allows higher standard for arsenic in some areas, because of the specific regional lithology and outdated water supply system, which determines higher background value for this harmful element. However, the regulations define the MPC of only a few elements (Table 1), and many trace elements are usually not analyzed. For a better assessment of the quality of drinking water ,there is a need for indications on their concentrations and ranges of variation. Therefore, in this research, in addition to the elements specified in the regulations, additional major and trace elements were analyzed, including the group of rare earth elements (REEs). Their mobility is generally very low, so their concentrations in drinking water are in the order of ng L−1. However, natural or human origins may lead to elevated levels of REEs in groundwater. For instance, weathering processes, enhanced by deposition of acid rains,
Environ Sci Pollut Res (2015) 22:6789–6799 Table 1 Maximum contaminant level for trace elements in drinking water, expressed as μg L−1 or mg L−1, permitted by Croatian, WHO, and EPA regulations
a
MCL allowed when existing water treatment cannot remove excessive arsenic and there is no other possibility of water supply for the population in the given area
b
Expressed in mg L−1
Element
Croatia
WHO
EPA
Ag Al As Ba Be
10 200 10 (50a) 700 –
– 200 10 700 –
100 50–200 10 2000 4
5 50 2 200 12 50 – 200 20 10 5 10 – – 5 3
3 50 2 – – 400 70 – 70 10 20 40 – 30 – 3
5 100 1 300 – 50 – – – 15 6 50 2 30 – 5
Cd Cr Cub Fe Kb Mn Mo Nab Ni Pb Sb Se Tl U V Znb
as well as the use of phosphate fertilizers (De Boer et al. 1996) could cause release of REEs to the groundwater. The importance of the determination of REEs in drinking water is associated with their possible adverse effects on human health (Rim et al. 2013, and references therein). The objectives of this study are as follows: (1) to assess the levels of trace and major elements and 238U in Croatian tap waters originating from different types of aquifers, (2) to get an overview of spatial variations in REE abundances and fractionation patterns, and (3) to determine the major processes and factors controlling the concentrations of these elements in tap waters. In this paper, the levels of the rare earth elements in drinking waters deduced from different aquifer types found on Croatian territory have been presented for the first time.
Materials and methods Hydrogeological setting Hydrogeological features of certain areas (Fig. 1) are closely associated with their geomorphological characteristics. On Croatian territory, three macro-geomorphological units can be outlined reflecting at the same time differences in the characteristics of the aquifers: the Pannonian basin, the
Environ Sci Pollut Res (2015) 22:6789–6799
6791
Fig. 1 Map of sample locations with indicated general hydrogeological characteristics of the aquifer (the dashed line represents the boundary between carbonate and non-carbonate aquifers; the color intensity of the gray scale shows the hydraulic conductivity of the aquifer; whitecolored areas are areas without significant aquifer)
Dinaridic Mountains (the Dinarides), and the Adriatic Sea depression. The northern and eastern Croatia are parts of the southern margin of the Pannonian basin dominated by the Sava and Drava river plains. The most important aquifers in this area are formed in the Quaternary sediments in the lowlands of the Sava and Drava rivers and are recharged by infiltration of precipitation and water from surface flows (Brkić et al. 2010). To the west rise the Dinarides mainly composed of Mesozoic carbonate deposits and are considered the largest continuous karst region in Europe. Numerous aquifers, very important for water supply, occur within the Dinarides, and their main characteristics are the abundance of karst geomorphological forms and deficiency in surface water (Biondić et al. 1998). Despite the fact that the Dinaridic Mountains are rich in precipitation, with up to 4000 mm a year, especially in the mountainous ranges along the Adriatic Sea coast, surface streams are rare. Overall, large area and a high quantity of precipitation result in the large abundance of groundwater. However, spatial and temporal availability of water causes problems with water supply at local level, especially in the dry season on the islands and coastal areas. Sample collection and preservation Tap water consumed in cities from various (hydro)geological regions of Croatia (the Pannonian basin in the north and east part of the country, the Dinarides and the Adriatic Sea
depression in the west and south part), with bedrock aquifers of various depths, were chosen for analysis. Sample locations of the analyzed tap waters, along with the rough hydrogeological region border, are shown in Fig. 1. The associated sample IDs are also given in Table 2. The tap water samples were collected during 2012 at consumers’ houses directly in 20-L plastic containers. Containers were previously washed with HNO3 and rinsed with the sample. To minimize precipitation and adsorption onto container walls, the samples were acidified with concentrated HNO3 to pH 2 immediately after collection according to ISO 5667–5:2006 procedure. Instruments Mulitielemental analysis of prepared samples was performed by high-resolution inductively coupled plasma mass spectrometry (HR-ICP-MS) using an Element 2 instrument (Thermo, Bremen, Germany). The measurements of the selected isotopes were performed at three different resolutions: low resolution (7Li, 9Be, 85Rb,95Mo, 109Ag, 111Cd, 120Sn, 121Sb, 133 Cs, 205Tl, 208Pb, 209Bi, 238U), medium resolution (23Na, 25 Mg, 27Al, 42Ca, 47Ti, 51 V, 52Cr, 55Mn, 56Fe,59Co, 60Ni, 63Cu, 66 Zn,86Sr, 89Y, 138Ba, 139La, 140Ce, 141Pr, 145Nd, 147Sm, 151 Eu, 157Gd, 159 Tb, 163Dy, 165Ho, 167Er, 169Tm, 171Yb, 175 Lu), and high resolution (75As, 77Se). External calibration was used for the quantification. For alpha-particle spectrometric measurements of uranium isotopes (234U and 238U), an alpha spectrometer (Alpha
6792 Table 2 Mean concentrations of elements (μg L−1) obtained for tap water (TW) samples (n=3)
Environ Sci Pollut Res (2015) 22:6789–6799
Ag Al As Ba Be Bi Ca Cd Co Cr Cs Cu Fe K Li Mg Mn Mo Na Ni Pb Rb Sb Se Sn Sr Ti Tl U V Y Zn La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu ΣREE Eu/Eu* Ce/Ce* La/Yb
TW1
TW2
TW3
TW4
TW5
TW6
TW7
TW8
0.116 44.6 30.3 109 0.021 0.002 80,730 0.019 0.144 0.406 0.087 10.5 64.1 1,560 5.76 25,410 23.8 0.49 91,380 1.22 1.61 0.850 0.042 0.030 0.029 369 0.772 0.011 0.116 0.180 0.085 37.2 0.064 0.070 0.028 0.049 0.014 0.046 0.010 0.002 0.016 0.002 0.006 0.001 0.006 0.001 0.313 17.7 0.39 1.04
0.098 26.4 0.13 47.2
