Contamination of Surface Waters by Heavy Metals in the Brno Region and the Assessment of Health Hazards

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1 Contamination of Surface Waters by Heavy Metals in the Brno Region and the Assessment of Health Hazards JOSEF NAVRATIL, JOSEF KELLNER, FRANTISEK BOZEK, ALENA LANGEROVA Civil Protection Department University of Defence 65 Kounicova, Brno CZECH REPUBLIC josef.kellner@unob.cz Abstract: - Within the range of 2004 up to 2008 the occurrence of heavy metals, such as mercury, cadmium and lead, was monitored in the part of the Svratka River basin in the Brno area. Non-carcinogenic health risk assessment was carried out with regard to the character of monitored metals and their adverse effect on the human organism and the utilization of the river for recreational activities. To assess risk, exposure scenarios were developed which considered the exposure resulting from dermal contact with contaminated water during swimming or showering and the exposure to accidental ingestion of contaminated water during residential stays or holidays. At the same time, a proposal of measures was submitted. The measures will allow the reduction of contingent health hazards and will contribute to the protection of surface waters in the region against possible sources of contamination. Key-Words: - Cadmium, Health, Lead, Mercury, Risk Assessment, Surface Water, Water Contamination Introduction The problems of surface water contamination are relevant in all countries of the world. Water has both economic and ecological value. It is necessary to take into consideration that the differences between water supply and its consumption increase permanently and one can assume that water consumption will continue to increase in the years to come. In contaminated surface waters, various forms of heavy metals, especially cadmium, mercury and lead occur very often. It is, therefore, necessary to analyze these pollutants, to monitor their occurrence and migration in individual components of the environment. It is essential not only to obtain the most precise information possible regarding their propagation and fate in the environment, but also to eliminate their occurrence and release from the sources of contamination, especially in the areas affected by industrial of agricultural activities. The implementation of precautionary as well as subsequent measures is a method of how to prevent not only hazards to human health and lives, but also the damage to other organisms which occur in individual components of the environment. 2 The Analysis of Current State The issue of surface water purity is very complicated, which is contributed to by the fact that surface waters are a water source as well as a receiving stream, i.e. a water body which receives water from a particular river basin or wastewater. The degree of aquatic environmental disturbance fully corresponds to the entirely adverse conditions of the other components of the environment. Based on US EPA, 4 substances of organic origin and 5 pollutants of inorganic origin, e.g. antimony, arsenic, beryllium, cadmium, chromium (III), chromium (VI), copper, lead, mercury, nickel, selenium, silver, thallium, zinc, cyanide, and asbestos are considered to be main pollutants occurring in surface waters []. The water quality is affected by the point sources of contamination of municipalities, by industrial plants and stock farming as well as the area sources of contamination, such as contamination caused by field economy, atmospheric deposition and sheet washes. The ratio is different in various regions of the Czech Republic depending on the population density, the method of drained wastewater treatment, the intensity and method of field economy and the amount of contamination from rain precipitation. The limiting value of the concentration in surface water must be less than 0. µg.dm -3 for Cd, 3.0 µg.dm -3 for Pb and 0.05 µg.dm -3 for Hg if the water to class I, i.e. very pure water, may by included. For the classification to class V, i.e. heavily contaminated water, the values of concentrations are determined as follows: grater than or equal to 2 µg.dm -3 for Cd, 30 µg.dm -3 Pb and µg.dm -3 for Hg [2]. The pollutants monitored get to the aquatic environment especially due to anthropogenic activities. Phosphate fertilizers, wastewater treatment sludge and plating wastewater are a major source of cadmium ISSN: ISBN:

2 pollution. Cadmium can get to the atmosphere not only due to the incineration of fossil fuels, fuel oils or petroleum, but also due to the incineration of waste plastics with dyestuffs or stabilizers containing this element and then due to its migration to the aquatic environment. Atmospheric waters contaminated by the incineration of fossil fuels and wastes are a source of mercury in surface waters. Also mercury compounds contained in some industrial waste waters may be secondary sources of mercury. Mercuric pesticides, preservatives and seed treatment agents used in agriculture come into question as well. Motor vehicle exhaust gases containing tetraethyl lead degradation products are a main anthropogenic source of surface water pollution by lead. However, emissions of this type have decreased considerably after the introduction of unleaded fuels. Other sources of contamination may be e.g. the production of accumulators and anticorrosive paints, wastewater coming from ore processing, colour metallurgy and glass industry or discarded metal working. The spectrum of adverse effects of cadmium, lead and mercury on the human organism is extensive. The severity of cadmium impact on the human organism rests in its long biological half-life (0-30 years) of eliminating from the organism. Cadmium affects adversely calcium metabolism and i.e. the production of vitamin D. As a result of cadmium action necrosis and tumours in gonads, kidney failure or disorders of the cardiovascular system have been observed. Cadmium poisoning may injure kidneys, liver and gonads; it may affect the blood pressure. Further, cadmium may injure foetus, it also has carcinogenic effects [3]. Lead toxicity lies in the ability of making a strong bond with sulphhydryl groups which are parts of some enzymes, in adverse action on red blood cells and the nervous system. Lead cumulates in bones with long-term exposure [4]. With regard to mercury, the amount and form are decisive for the cumulative effect. Already low doses of mercury organic compounds have neurotoxic effects and can afflict kidneys where they cumulate. The interactions with essential microelements may also be considerable. Methyl mercury has teratogenic effects as well, e.g. blast injury risk occurs in mothers whose concentration of mercury in hair achieves approximately 5-20 mg.kg - [5]. These aspects led to the decision to monitor the pollutants concerned in the surface waters of the observed region and to carry out human-health risks assessment of non-carcinogenic effects caused by discussed metals to affected population. 3 Problem Solution 3. Employed Methods and Devices The concentration of the metals concerned, i.e. Cd, Hg and Pb, in surface waters of the Brno region were monitored in five sampling points on the Svitava and Svratka Rivers. The selection of sampling points and their location was carried out both in view of the residential stay of the population and in view of the assessment of a possible change in the composition of waters after their flow through the Brno area. Therefore, the sampling points in the rivers were defined as follows: Sampling Point the Svitava River before the area, Sampling Point 2 the Svitava River in the area, Sampling Point 3 the Svratka River before the area, Sampling Point 4 the Svratka River in the area and Sampling Point 5 after the junction of the Svitava and Svratka Rivers. Water samplings from sampling points were performed by Povodi Moravy s.p. based on the norm [6]. The statistical method of sampling was applied which consisted in spot sampling from the bank from the depth of 25 cm with minimum affection of hydrodynamic and hydrochemical conditions. The samplings were carried out regularly twice a month in the period of 2004 up to For determining the Cd, Pb and Hg concentrations in the obtained samples, the analysis technique of ICP-MS was used in the laboratories of Povodí Moravy s.p. and was carried out in accordance with standard operating procedures [7, 8]. The risk assessment method was used in compliance with the legal system of the Czech Republic [9] while observing the U.S. EPA method [0]. 3.2 Findings and Discussion Based on the evaluation of the data obtained in the course of monitoring the water quality aimed at the contents of Cd, Pb and Hg in the part of the Svitava and Svratka river basins in the period of 2004 up to 2008, it followed that there was no impairment in water quality after the flow of the rivers through the Brno area. In the interim on the contrary, there was a slight decrease in the contents of these pollutants in monitored waters, especially of Pb, as an effect of the measures implemented with consumers and users for increasing the quality of drained wastewaters. Based on the norm [2] it was possible to classify the monitored sampling points as class III, i.e. contaminated water or, if need be, class II meaning slightly contaminated water from the viewpoint of metal contents. When assessing the water quality in individual sampling points, obvious tendency leading to the decrease in Hg content in water was detected in ISSN: ISBN:

3 Sampling Point 3. In relation to Cd, the highest concentration, 0.365x0-3 mg.dm -3, was measured in Sampling Point 5 in However, it was only a onetime increase in concentration which did not significantly affect the classification of the course to the quality class. The higher content of pollutants was detected in Sampling Points and 3 located in the areas used intensely in agriculture where synthetic fertilizers and preparations are used and where soluble forms of metals migrate from the soil environment to the aquatic environment due to the sheet wash. Maximum concentrations of the pollutants concerned detected in the course of 2004 up to 2008 in the determined sampling points of the Svratka and Svitava Rivers were used subsequently as primary input data for the health risk assessment. These concentrations are presented in Table. At the beginning, two exposure scenarios were selected which considered the exposure resulting from dermal contact with contaminated water during swimming or showering and the exposure resulting from accidental ingestion of contaminated water during residential stays or holidays. The second exposure scenario was rejected in the course of monitoring after continuous assessments and calculations with regard to the low concentrations of pollutants in water samples and exposure frequency. The level of risk for substances with the threshold (non-carcinogenic) effect is represented by hazard quotient HQ. If HQ the risk is negligible if HQ (; 4 the risk is tolerable and if HQ > 4 is unacceptable [0, ]. For calculating the hazard quotient the following relation () was used HQ = ADD RfD () where ADD [mg.kg -.day - ] is the average daily dose and RfD [mg.kg -.day - ] means the reference dose. The dermal reference dose RfD d = 5.0x0-6 mg.kg.day - was taken in calculations for Cd and RfD d = 2. x0-6 mg.kg -.day - for Hg. The dermal reference dose for Pb, RfD d = 3.5x0-6 mg.kg -.day - was derived from the reference dose for the oral exposure RfD o using the following equation (2): RfD = RfD AB (2) d where AB SGI is a fraction of the lead contaminant absorbed in the gastrointestinal tract and having the value of 0-3 []. ADD was calculated using the equation (3) and the values of exposure factors for the dermal exposure scenario were obtained from the national standard [9]. ADD = C AT o w SA Kp ET EF ED CF BW (3) In equation (3), C W indicates the highest detected concentration of Cd, Pb and Hg pollutants [mg.dm -3 ] in the monitored period of 2004 up to 2008 how is evident from Table. In calculating, it was taken into account that an individual is exposed to contaminated water only on his/her face, forearms and soles and the skin area amounts SA M = 3.053x0 3 cm 2 with an exposed man, SA w = 2.545x0 3 cm 2 with an exposed woman and SA C =.70x0 3 cm 2 with a child. The permeability coefficient of the penetration through the skin K p = 0-3 cm.hour - for Cd and Hg, and K p = 0-4 cm.hour - for Pb [43]. The exposure time was considered ET A = 0.25 hour.day - with the adult population and ET C = 0.33 hour.day - with children, while the exposure frequency EF = 60 days a year. The ED A = 30 years represents the exposure duration adults and ED C = 6 years for children. Further, the conversion factor CF = 0-3 dm -3.cm -3 and body weight BW A = 70 kg for adults and BW C = 5 kg for children up to six years were used in calculations. Finally it was assumed that averaging time AT A = 0950 days for the adult population and AT C = 290 days for children and at the same time that the concentration of observed metals would stay roughly constant in this time period. The calculation of ADD for the metals monitored for dermal contact with water during swimming or showering is given in Table 2. For the processed exposure scenarios of dermal contact with water during swimming or showering during residential stay of population hazard quotients were calculated and their values for non-carcinogenic effects are presented in Table 3. SGI Table Maximum concentrations of Cd, Hg and Pb determined in the monitored sampling points of Povodi Moravy s.p. in the period of 2004 up to 2008 Maximum concentrations of C W [mg.dm -3 ] of selected pollutants in appointed sampling points Pollutant within the range of 2004 up to Cd E E E E E-03 Pb 6.80 E E E E E-03 Hg E E E E E-03 ISSN: ISBN:

4 Table 2 Calculated values of ADD A for adults and ADD C for children in case of dermal contact with water during swimming and showering Sampling point Pollutant ADD [mg kg - day - ] Man Woman Child Cd E E E-09 Pb.220 E E E-09 Hg 8.96 E E E-09 Cd E E E-0 Pb.953 E E E-09 Hg E E-0.3 E-09 Cd E E E-09 Pb 6.94 E-0 5,63 E E-09 Hg E E E-0 Cd.65 E E E-0 Pb E E E-0 Hg.254 E E E-0 Cd.953 E E E-0 Pb E E-0.88 E-09 Hg 8.96 E E- 2.5 E-0 Table 3 Findings of non-carcinogenic risk assessment for dermal contact expressed by the hazard quotient HQ Sampling HQ for residential stay Pollutant point Man Woman Child.308 E E E E E E-04 3 Cd.347 E E E E E E E E E E E E E E E-03 3 Pb.769 E-04,475 E E E E E E E E E E E E E E-04 3 Hg.877 E E E E E E E E E-05 It is evident from Table 3 that HQ << for all observed heavy metals. Thus it can be claimed that in dermal contact with so contaminated surface water there are not and cannot be expected any significant toxic effects caused by the monitored heavy metals which could affect human health or lives. With regard to the exposure scenario, the population staying in the monitored locality will not be exposed to the risk of adverse toxic effects of Cd, Hg and Pb, the presence of which in surface waters of the monitored area was confirmed using the analyses made. Certain limitations, uncertainties a vagueness can be connected with values of the hazard quotients. The most important uncertainties may be as follows: a) The determined metals in the aquatic environment are distributed in a soluble and insoluble form and the ratio of both forms is dependent on the ph value and the concentration of dissolved gases, especially CO 2, and the adsorption on sediments. b) The uncertainties connected with the sampling, transport and sample custody or, if need be, with the use of an unsuitable preservation. c) The uncertainties connected with the determination of findings in an accredited laboratory. These may ISSN: ISBN:

5 be e.g. standard uncertainties of measurements expressed in the form of a variation coefficient which ranged from ± 6 to ± 5 % in case of tests. d) The vagueness connected with the reference dose determination was another problem. The U.S. EPA evaluates itselves the validity of reference doses as middle. Furthermore, the derivation of the dermal RfD d from the oral RfD o may lead to another vagueness of values entering the calculation of health risk assessment. e) The limitations lie especially in the dependence on the range of the area concerned. Only a small part of the Svitava and Svratka Rivers was taken into consideration for the taking of samples. f) The evaluation of the dose-response relation can also be considered a problem. The penetration of contaminants to organisms is different with regard to the age, sex or physical condition of a person exposed and the possibility of exposure from other sources as well as the effects of other substances were not taken into account. g) It is also necessary to consider some inconsistencies occurring in national standard [9] for risk assessment. It concerns e.g. the stated BW A = 70 kg, which can be a questionable value. Here, the US EPA recommendation should be taken into consideration which states that particular exposure factors should be in conformity with national conditions, the assessments of accredited laboratories or they should be discussed with experts, etc. h) Another fact is that only an accidental contact of the population with contaminated water is considered and that the concentrations of the substances monitored are constant in the course of the entire exposure duration. Thus, simplified and critical exposure scenarios are under consideration. i) For calculating health risk the values of exposure factors stated in national standard [9] were used and, therefore, the risks may be rather overestimated. However, the use of maximum values for the calculation is recommended, namely for the reason of preliminary precaution since the more precise identification of a threat source and the timely taking of corrective actions are provided. 4 Conclusion The long-term monitoring of the water quality has proved that the concentrations of cadmium, lead and mercury do not increase after the flow of the Svitava and Svratka Rivers through the Brno area and thus the water quality within the area monitored is not affected. Based on the analysis of findings regarding the assessment of non-carcinogenic risks, it can be stated that the population staying in the monitored locality is not exposed to the risks of adverse toxic effects of cadmium, mercury and lead and there is a faint possibility that more serious or even fatal injuries to the human organism will occur after the incidental contact with contaminated water. In the following phase of work, however, it will be useful to take advantage of the experimental data on concentrations of pollutants in waters to assess carcinogenic risks and to monitor the concentrations of pollutants in river sediments. References: [] U.S. EPA. Clean Water Act Analytical Test Methods. List of Toxic and Priority Pollutants. [on line]. [ ]. URL: gov/waterscience/methods/pollutants.htm. [2] CSN Quality of Water - Surface Water-Quality Classification. Prague: Czech Standards Institute, p. [3] Jarup L. Hazard of Heavy Metal Contamination. British Medical Bulletin. 2003, 68, [4] Goyer A. Toxic and Essential Metal Interactions. Annual Review of Nutrition.997, 7, [5] Clarkson W., Magos L. The Toxicology of Mercury and Its Chemical Compounds. Critical Reviews in Toxicology. 2006, 36, 8, [6] CSN ISO ( ). Quality of Water - Water Sampling, Part 6. Prague: Czech Office for Standards, Metrology and Testing, 999. [7] CSN EN ISO ( ). Quality of Water. The Application of Technique of Inductively Coupled Plasma - Mass Spectrometry (ICP MS) Part 2: Determination of 62 Elements. Prague: Czech Office for Standards, Metrology and Testing, [8] U.S. EPA. Method Determination of Metals and Trace Elements in Water and Waste by Inductively Coupled Plasma - Atomic Emission Spectrometry. [on line]. [ ]. URL: < rscience/methods/method/files/200_7.pdf>. [9] Ministry of Environment (MoE). MoE. Methodical Instructions No 2 for the Risk Analysis of Contaminated Area. MoE Bulletin, 2005, XV, article 9. ISSN: ISBN:

6 [0] U.S. EPA. Risk Assessment Guidelines of 986. EPA/600/8-87/045. Washington, DC: U.S. EPA, 987. [] Bozek F. Risk Management. st Ed. Brno: University of Defence, s. ISBN [2] U.S. EPA. Integrated Risk Information System (IRIS). Datebase of Toxicological Parameters for Human Health. [on line]. [ ]. URL: < ISSN: ISBN: