Assessment of Environmental Arsenic Levels in Prievidza District
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Journal of Exposure Analysis and Environmental Epidemiology (2002) 12, 179 – 185 # 2002 Nature Publishing Group All rights reserved 1053-4245/02/$25.00 www.nature.com/jea Assessment of environmental arsenic levels in Prievidza district T. KEEGAN,a BING HONG,a I. THORNTON,a M. FARAGO,a P. JAKUBIS,b M. JAKUBIS,b B. PESCH, c U. RANFTc M.J. NIEUWENHUIJSEN a AND THE EXPASCAN STUDY GROUP d aDepartment of Environmental Science and Technology, Imperial College of Science, Technology and Medicine, London SW7 2BP, UK bState Health Institute, Prievidza, Slovakia cMedical Institute of Environmental Hygiene, Unit of Environmental Epidemiology and Biomonitoring, Dusseldorf, Germany A coal-burning power station in the Nitra Valley in central Slovakia annually emitted large quantities of arsenic (up to 200 tonnes) between 1953 and 1989. Since then, pollution-control measures have reduced arsenic emissions to less than 2 tonnes a year. However, the power station was still a source of airborne arsenic pollution. As part of an EU-funded study on exposure to arsenic and cancer risk in central and Eastern Europe we carried out a study of environmental levels of arsenic in the homes and gardens of residents of the district. Garden soil samples (n=210), house dust samples (n=210) and composite house dust samples (n=109) were collected and analysed using inductively coupled plasma atomic absorption spectroscopy (ICP-AES) at Imperial College. The mean arsenic content of coal and ash in samples taken from the plant was 519 g/g(n=19) and 863 g/g(n=22), respectively. The geometric mean (GM) arsenic concentration of garden soils was 26 g/g (range 8.8–139.0 g/g), for house dust 11.6 g/g (range 2.1–170 g/g) and for composite house dust 9.4 g/g (range 2.3–61.5 g/g). The correlation between the arsenic levels in soil and in house dust was 0.3 (P<0.01), in soil and composite house dust 0.4 and house dust and composite house dust 0.4 (P<0.01 for both), i.e., were moderate. Arsenic levels in both house dust and soil decreased with distance from the power station. Overall, levels in both fell by half 5 km from the point source. Weak correlations were seen between the total urinary arsenic concentrations and arsenic concentrations in composite house dust. Journal of Exposure Analysis and Environmental Epidemiology (2002) 12, 179 –185 DOI: 10.1038/sj/jea/7500216 Keywords: arsenic, skin cancer, environmental exposure, airborne, coal, Europe, Slovakia. Introduction be increased by exposure to arsenic (Chen et al., 1986; Bates et al., 1992; Guo et al., 1994; Chiou et al., 2000). Arsenic is ubiquitous in the environment. It exists at a mean Many of these studies have been carried out in areas where concentration of 2 g/g in surface soils (Thornton and exposure to arsenic was via water, particularly in southwest Farago, 1997). In areas where the underlying geology or Bengal, Bangladesh, Taiwan and Chile. However, fewer environmental inputs produce arsenic levels can be higher. studies have addressed the possible association between In a former mining area in South West England arsenic skin cancer and exposure to arsenic from a point source. levels in soils have been measured at over 10,000 g/g Arsenic has been categorised as a class 1a human (Farago et al., 1997), though there was little evidence for carcinogen (IARC, 1987). effects on human health resulting from inhabiting those The Electrarne Novaky (ENO) power station at Novaky, areas where soil arsenic levels were high (Xu and Thornton Prievidza district, in central Slovakia has been in operation 1985). However, adverse health effects in residents of areas since the 1950s. Since that time it has emitted over 3000 where levels of arsenic are high have been observed. tonnes of arsenic, a result of burning local brown coal that Studies have suggested that incidence rates of certain has a high arsenic content. In the 1960s and 1970s the plant cancers, including those of the lung, bladder and skin, can emitted around 200 tonnes of arsenic a year, but in the 1980s the first pollution control measures were put in place and since then the levels of arsenic emitted have fallen to below 1. Address all correspondence to: Dr. M.J. Nieuwenhuijsen, Department of 2 tonnes a year. These measures included raising the height Environmental Science and Technology, Imperial College of Science, of one stack to 300 m coupled with electrostatic Technology and Medicine, London SW7 2BP, UK. Tel.: +44-20-7594- precipitators and flue-bed desulphurisation technology. 6384. Fax: +44-20-7594-6408. Most of the ash from the plant was stored in open pits Received 4 March 2002. dBencko V., Colvile R., Cordos E., Docx P., Fabianova E., Farago M., less than 5 km from the plant. A proportion of this ash was Frank P., Go¨tzl M., Grellier J., Hong B., Rames J., Rautiu R., Stevens E., used in the local manufacture of building blocks. Coal was Thornton I., Zvarova J. also burnt in homes. Since the 1980s, waste hot water from Keegan et al. Environmental arsenic levels in Prievidza District the plant has been piped to the main urban conurbations to Bratislava. It is the largest town and capital of Prievidza provide water for central heating systems. This cut the district, a region of the Trencin administrative area. The amount of coal burnt domestically. region has been a mining area for centuries; towns such as Prievidza district has had a consistently high rate of Banska Bystrica, Kremnica and Banska Stianvica are three nonmelanoma skin cancer (NMSC) since registering cancer of the original seven mining towns colonised by German incidence began in Slovakia in 1968 (Plesko et al., 2000). miners in the 14th century from where they extracted Data from the National Cancer Registry of Slovakia shows copper, gold and silver. Prievidza was principally associated that in 1996 the rates of NMSC in the district for both men with coal mining. The coal it produces from the three mines and women was the highest in the country, and rates in the around the town goes to fuel the large power station in area have been consistently high compared to other districts Novaky, 10 km to the south. since 1985. The age-adjusted rates (world standard) in 1996 were 95/100,000 and 71/100,000 for men and Garden Soil Collection women, respectively. The country rate in 1996 for NMSC Garden soil was collected from 210 households randomly was 48/100,000 for men 35/100,000 for women, and had selected from the study population of the case–control increased from a rate of 26/100,000 for both men and study. Each sample was a composite of 20 subsamples (0–5 women in 1968. The number of NMSC cases in Slovakia cm) collected with a stainless steel trowel. Where possible, increased from 587/573 (men/women) in 1968 to 1576/ the samples were collected from the householder’s own 1505 in 1996, an approximately threefold increase (Slovak garden. If vegetables were grown, soil was collected from Central Cancer Registry, 1996). However, a previous study the vegetable patch as well as from other areas of the garden. of cancers in the district found that NMSC rates were higher If the household was a flat and had no garden but an in Banska Bystrica, a nearby town, than in Novaky itself allotment nearby the sample was taken from there. If the (PHARE, 1995). household had no allotment a sample was taken either from A case–control study (EXPASCAN) was designed to the communal garden area or from a nearby amenity area, as test the possible association between the emissions for the close as possible to the entrance. In some cases (10%), none power station and the high rates of NMSC (Pesch, 2002). of these was possible and no sample was taken. Samples The routes of exposure to airborne arsenic from a point were collected in wet-strength paper craft bags and stored in source could be through inhalation, dermal absorption or the a clean, dry place until transport to Imperial College, gastrointestinal tract (Polissar et al., 1990; Farago et al., London was arranged. 2000). For this study, arsenic exposure was assessed in three House dust was collected from 210 homes. In each ways. First, total arsenic was measured in the garden soil. household two samples were collected, one was dust Also, levels of arsenic in coal and ash from the power plant collected from a measured area of carpet, the other a sample were assessed in this study, as were arsenic emissions over from the householder’s vacuum cleaner. The house dust the active lifetime of the power plant. Second, current and sample was collected using an Imperial College-adapted historical levels of airborne arsenic were modelled using an vacuum cleaner. One square meter of carpet in the main air dispersion modelling system (ADMS) based on living area was vacuumed for 2 min. The dust was collected emission data (Colvile et al., 2001). Third, arsenic uptake in a Whatman cellulose filter fitted to the inspiration pipe of from the food chain was assessed with data from a the cleaner (Watt et al., 1993). The filters were stored in preceding project, PHARE (Fabianova and Bencko, labelled, sealed plastic bags until preparation and analysis. 1995). Some routine data for local drinking water quality Where there was no carpet in the main living area another were available, but not for the past. Furthermore, urine room was sampled. (In most households the kitchen was the samples were taken from each participant and their urine main living room and was often carpeted, and this was often arsenic content measured (EXPASCAN, 2001).