Environmental fate and bioavailability of wood preservatives in freshwater sediments near an old sawmill site.

Impacts of an old contaminated sawmill site located in Eastern Finland were studied, with emphasis on transportation and bioaccumulation of wood preservatives in the surrounding water system. To assess the transportation of chlorophenols and chromated copper arsenate (CCA) from the sawmill to the nearby lake, the concentrations of these compounds in selected sediment samples were analyzed. To assess the contribution of a pulp mill further upstream, the concentration of extractable organic halogens (EOX) was analyzed. Bioaccumulation of wood preservatives from sediments was examined using Lumbriculus variegatus as test organism. In sediments collected from the sawmill area, concentrations of chlorophenols, arsenic, chromium and copper were high. In the surrounding area the concentrations of these compounds were slightly elevated at some sampling points but were mostly within the natural range of variation. Thus, it can be concluded that transportation of wood preservatives from the sawmill area to its surroundings is fairly low. However, 60 microg/l of arsenic and 50 microg/l of copper were found in water taken from a brook that runs through a landfill area of the sawmill to the nearby river, and the concentration of arsenic in the surface sediment at one sampling point in the lake was slightly elevated. The total amount of organohalogens in sediment was higher in the river and the lake than in the sawmill area. Of all the wood preservatives studied, only arsenic was found to bioaccumulate in present conditions, reaching a tissue concentration of 362 microg/g dw in organisms exposed for 28 days to sediment from the brook. High concentration of arsenic in oligochaeta tissue was related to high concentration of arsenic in the pore water.     

Levels of chlorinated compounds (CPs, PCPPs, PCDEs, PCDFs and PCDDs) in soils at contaminated sawmill sites in Sweden

Soil samples from five contaminated sawmill sites in Sweden were characterized with respect to chlorophenols (CP), chlorinated phenoxy phenols (PCPP, hydroxylated chlorinated diphenyl ethers), chlorinated diphenyl ethers (PCDE), chlorinated dibenzofurans (PCDF) and chlorinated dibenzo-p-dioxins (PCDD). The composition of chlorinated compounds in the soil samples was compared to the composition of two preservatives commonly used in the Scandinavian wood impregnation industry: the 2,3,4,6-tetrachlorophenol preservative called Ky-5 and the pentachlorophenol preservative Dowicide G. The levels of CPs in the soil samples ranged from 0.1 to 4500 mgkg-1 d.w., PCPPs from <0.15 to 940 mgkg-1 d.w., PCDEs from <38 to 6800 microgkg-1 d.w., PCDFs from 7.4 to 18000 microgkg-1 d.w. and PCDDs from 9.9 to 35000 microgkg-1 d.w. The resulting WHO-TEQ of PCDD/Fs in the soil samples ranged from 0.14 to 3000 microgkg-1 d.w. Despite a wide range of concentrations the congener compositions were similar within tetrachlorophenate and pentachlorophenate contaminated soils respectively. The contamination at each sawmill site may be linked to the use of either a tetrachlorphenol preservative, e.g. Ky-5, or a pentachlorophenol preservative, e.g. Dowicide G. Best-fit calculations were used to compare the chlorinated phenol contents of the preservatives to those of the soil samples. This revealed a positive correlation between the hydrophobicity (logKow) of contaminants and the ratio of their levels in soil to preservatives. The relative abundance of the chlorinated compounds varied greatly between the five sites studied, suggesting that their transport parameters differ substantially.     

Soil contamination at abandoned sawmill areas

Contamination of soil by technical chlorophenol formulation at wood preserving sites was studied. The examined soils contained 50 to 1000 mg of polychlorinated phenols (CPs), 1 to 50 mg of polychlorinated phenoxyphenols (“pre-dioxins”, PCPPs) and 0.1 to 5 mg of polychlorinated dibenzofurans (PCDFs) per kg of dry soil. CPs were found to be mobile, leaching deep into the soil, while PCPPs and PCDFs accumulated in the top soil. All three classes of contaminants were stable in soil.     

A wood preservative metabolite in river water

- A previously unknown pollutant in river water was identified to be 2-mercaptobenzothiazole (2-MBT) by interpretation and simulation of its GC/LRMS spectrum. Further GC/HRMS measurement of the isotope composition of the molecular ion verified this structure. 2-MBT is a well-known agent for corrosion inhibition and a stable metabolite of several other benzothiazoles. The present 2-MBT trace was most probably a metabolite of the wood preservative TCMTB which leaked from an upstream sawmill. The metabolite had been detected earlier in urine of the sawmill workers, but now was identified in the recipient water environment for the first time.     

Microbial activities in soils of a former sawmill area

To find out microbial metabolic functioning and toxicity in a former sawmill area, carbon dioxide evolution, methane oxidation potential, 10 hydrolytic enzyme activities, Vibrio fischeri test, fluorescein diacetate hydrolysis activity (FDA), soil pH, carbon, nitrogen and pentachlorophenol (PCP) content were measured at four sites. The area is contaminated with aged chlorophenols. Chlorophenol content of soil was analyzed with a novel HPLC-MS technique, which allowed to measure chlorophenols without derivatization. The sites had a pollution gradient from 0.5 to 15 microg PCP g dw of soil(-1). Endogenous carbon dioxide evolution, methane oxidation potential, butyrate-esterase, acetate-esterase, sulphatase and aminopeptidase activities were lower at the site 2 than 3, although the site 2 and 3 had similar content of carbon and nitrogen. The soil was toxic in V. fischeri test at the site 2, which had high content of PCP (3.93+/-1.00 microg PCP g dw of soil(-1)). The results indicated that endogenous carbon dioxide evolution, methane oxidation potential, butyrate-esterase, acetate-esterase, sulphatase and aminopeptidase activities were sensitive to PCP in the soil. The results indicated that alpha-glucosidase, beta-glucosidase, beta-xylosidase, beta-cellobiosidase, phosphomonoesterase, N-acetyl-glucosaminidase activity and FDA hydrolysis activity were not sensitive to PCP in the soil. Soil processes involved in the cycling of carbon, nitrogen, sulphur and phosphorus were only slightly vulnerable in the former sawmill area and most sensitive microbial species were probably replaced with more tolerant ones to maintain and recover functioning of the former sawmill soils.     

Spatial variability of arsenic and chromium in the soil water at a former wood preserving site

Contamination of industrial sites by wood preservatives such as chromated copper arsenate (CCA) may pose a serious threat to groundwater quality. The objective of this study was to characterise the spatial variability of As and Cr concentrations in the solid phase and in the soil water at a former wood impregnation plant and to reveal the fundamental transport processes. The soil was sampled down to a depth of 2m. The soil water was extracted in situ from the vadose zone over a period of 10 months at depths of 1 and 1.5m, using large horizontally installed suction tubes. Groundwater was sampled from a depth of 4.5m. Results showed that arsenic and chromium had accumulated in the upper region of the profile and exhibited a high spatial variability (As: 21-621 mg kg(-1); Cr: 74-2872 mg kg(-1)). Concentrations in the soil water were high (mean As 167 microg L(-1); Cr: 62 microg L(-1)) and also showed a distinct spatial variability, covering concentration ranges up to three orders of magnitude. The variability was caused by the severe water-repellency of the surface soil, induced by the concurrent application of creosote wood preservatives, which leads to strong preferential flow as evident from a dye experiment. In contrast to soil water concentrations, only low As concentrations (<12 microg L(-1)) were detected in the groundwater. High Cr concentrations in the groundwater (approx. 300 microg L(-1)), however, illustrated the pronounced mobility of chromium. Our study shows that at sites with a heterogeneous flow system in the vadose zone a disparity between flux-averaged and volume-averaged concentrations may occur, and sampling of soil water might not be adequate for assessing groundwater concentrations. In these cases long-term monitoring of the groundwater appears to be the best strategy for a groundwater risk assessment.     

Use of handheld X-ray fluorescence spectrometry units for identification of arsenic in treated wood

The objective of this study was to evaluate the performance of handheld XRF analyzers on wood that has been treated with a preservative containing arsenic. Experiments were designed to evaluate precision, detection limit, effective depth of analysis, and accuracy of the XRF arsenic readings. Results showed that the precision of the XRF improved with increased sample concentration and longer analysis times. Reported detection limits decreased with longer analysis times to values of less than 1mg/kg or 18 mg/kg, depending on the model used. The effective depth of analysis was within the top 1.2 cm and 2.0 cm of sample for wood containing natural gradients of chemical preservative and concentration extremes, respectively. XRF results were found to be 1.5-2.3 times higher than measurements from traditional laboratory analysis. Equations can be developed to convert XRF values to results which are consistent with traditional laboratory testing.     

Layer of organic pine forest soil on top of chlorophenol-contaminated mineral soil enhances contaminant degradation

Chlorophenols, like many other synthetic compounds, are persistent problem in industrial areas. These compounds are easily degraded in certain natural environments where the top soil is organic. Some studies suggest that mineral soil contaminated with organic compounds is rapidly remediated if it is mixed with organic soil. We hypothesized that organic soil with a high degradation capacity even on top of the contaminated mineral soil enhances degradation of recalcitrant chlorophenols in the mineral soil below. We first compared chlorophenol degradation in different soils by spiking pristine and pentachlorophenol-contaminated soils with 2,4,6-trichlorophenol in 10-L buckets. In other experiments, we covered contaminated mineral soil with organic pine forest soil. We also monitored in situ degradation on an old sawmill site where mineral soil was either left intact or covered with organic pine forest soil. 2,4,6-Trichlorophenol was rapidly degraded in organic pine forest soil, but the degradation was slower in other soils. If a thin layer of the pine forest humus was added on top of mineral sawmill soil, the original chlorophenol concentrations (high, ca. 70 μg g^?1, or moderate, ca. 20 μg g^?1) in sawmill soil decreased by >40 % in 24 days. No degradation was noticed if the mineral soil was kept bare or if the covering humus soil layer was sterilized beforehand. Our results suggest that covering mineral soil with an organic soil layer is an efficient way to remediate recalcitrant chlorophenol contamination in mineral soils. The results of the field experiment are promising.     

Dioxin exposure in contaminated sawmill area: the use of molar teeth and bone of bank vole (Clethrionomys glareolus) and field vole (Microtus agrestis) as biomarkers

Developmental disorders of teeth are among the most sensitive targets of polychlorinated dibenzo-p-dioxin and -furan (PCDD/F) exposure. In rats, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) reduces dose-dependently the size of molars, most severely the third lower molars. Dioxins also have effects on developing bone, including altered bone mineral density as well as reduced bending breaking force and stiffness. The aim of this study was to evaluate the use of the third lower molar and long bones as biomarkers of PCDD/F exposure in two wild vole species, the bank vole (Clethrionomys glareolus) and the field vole (Microtus agrestis) collected from a PCDD/F contaminated former sawmill area. Survey of soil and biota of the sawmill area indicated a PCDD/F contamination with a congener profile characteristic for the chlorophenol wood preservative Ky-5. The PCDD/F concentration in the bank vole was notably higher than in the field vole. The third molar of the bank vole was significantly smaller in dioxin-exposed animals compared to control group, while there was no difference between these two groups in the field vole. No significant alterations were observed in bone density and strength in either species except for reduced bending strength of the femur neck in bank vole males exposed to dioxins. Even though the bone changes are among the sensitive endpoints of dioxin-exposure, high variability due to age, size and gender limits their use as biomarkers of wildlife exposure. In conclusion, the size of molar teeth seems to be a sensitive and robust biomarker for PCDD/F exposure in wild bank vole populations and thus worth of further studies.     

Isolation and physiological characterization of the pentachlorophenol degrading bacterium Sphingomonas chlorophenolica

Many chlorophenols tend to persist in the environment, and they may become public health hazards. Among chlorophenols, pentachlorophenol (PCP) is a priority pollutant that has been used widely as a general biocide in commercial wood treatment. Owing to the rapid industrial growth, serious soil and water pollutions by chlorophenols has been reported in Taiwan. In this study, 10 indigenous PCP-degrading bacterial strains were isolated from a PCP-degrading mixed culture, and the potential of both the pure and mixed cultures for PCP degradation compared. Moreover, the physiological characteristics and optimum growth conditions of the PCP-degrading bacteria were investigated. One of the isolated bacterial strains with good potential for PCP degradation was characterized and identified as Sphingomonas chlorophenolica by 16S rDNA gene analysis. The result of the optimum growth temperatures revealed that this organism was a mesophile. The optimum pH for PCP removal by S. chlorophenolica was between 6.9 and 7.6. Increase in concentration of PCP has a negative effect on the biodegradation potential of S. chlorophenolica and PCP concentration above 600 mg l(-1) was inhibitory to its growth. The results of this study indicate that this S. chlorophenolica strain has a better potential for PCP degradation compared to the enriched mixed culture. The physiological characterization of the isolates also indicates the possible application of this strain for bioremediation of sites contaminated with PCP.     

Chlorophenols in lake bottom sediments: A retrospective study of drinking water contamination

Lake and brook bottom sediments were analyzed for chlorophenols to provide historical data of exposure assessment, after the water intake plant of a Finnish village had been found to be contaminated in 1987, and subsequently elevated non-Hodgkin lymphoma risk was detected. Highly elevated 2,3,4,6-tetrachlorophenol and pentachlorophenol levels were found in all four lake sediment cores investigated. The distribution was uneven with much higher concentrations in the estuary, in contrast to PCB compounds which were more evenly distributed within the basin. The inlet origin of the chlorophenols in the sediments was further supported by the regional distribution pattern of these compounds in the sediment and water along transects of the inlet and its tributaries. The composition of chlorophenol congeners in the sediments was similar to that in a commercial fungicide used by a local sawmill, but different from other sediment analyses reported in Finland, also implying a local source. Dating of three cores by Pb-210 and soot ball chronology indicated that the contamination of the watercourse started in the early 1970s at the latest but possibly earlier. This would provide the latency time required for tumour appearance in the 1970s and 1980s.     

Dioxins,chlorophenols and other chlorinated organic pollutants in colloidal and water fractions of groundwater from a contaminated sawmill site

BACKGROUND, AIM, AND SCOPE: The distribution of chlorinated organic contaminants in groundwater and the importance of colloids were studied in groundwater from a sawmill site contaminated by chlorophenol preservatives. MATERIALS AND METHODS: The groundwater was fractionated into three different size ranges: (1) >0.7 mum, (2) 0.4-0.7 mum and (3) 0.2-0.4 mum and the filtered water phase. The concentrations of chlorophenols (CP), chlorinated phenoxy phenols (PCPP), chlorinated diphenyl ethers (PCDE), chlorinated dibenzofurans (PCDF) and chlorinated dibenzo-p-dioxins (PCDD) were determined in each fraction. The colloids were characterised regarding the chemical composition using X-ray photoelectron spectroscopy (XPS). RESULTS: Chlorophenols were mostly found in the water fraction and PCDD/Fs were found almost exclusively in the particulate fractions. For example, the filtered water phase contained 2,100 mug l(-1) and 0.72 ng l(-1) for CPs and PCDD/Fs, respectively, and the particulate fractions contained 27 mug l(-1) and 32 ng l(-1) for CPs and PCDD/Fs, respectively. XPS evaluation of the particulate phases showed no correlation between the surface chemistry of the particle properties and the distribution of chlorinated compounds. DISCUSSION: The results suggest that groundwater transport of CPs, PCPPs, PCDEs and PCDD/Fs may occur from contaminated sawmill sites and that the colloid-facilitated transport, especially of PCDD/Fs, is substantial. The results correlated well with previous studies of compounds sorbed to dissolved organic carbon, which indicate that dissolved and colloidal organic carbon facilitated the transport of PCDEs, PCDFs and PCDDs particularly. CONCLUSIONS: Several classes of chlorinated compounds were readily detected in the groundwater samples. Due to the differences in their physicochemical properties, CPs, PCPPs, PCDEs and PCDD/Fs vary in their partitioning between colloidal fractions and the filtered groundwater. The proportion of the bound fraction increased with an increasing hydrophobicity of the chlorinated compounds. The groundwater transport of colloid-associated pollutants from the site may be significant. RECOMMENDATIONS AND PERSPECTIVES: The results imply that colloidal particles <0.7 mum are freely mobile in groundwater from this site. The groundwater transport of colloid-associated pollutants may be significant. However, the extent of the problem is not yet known and, thus, further research is needed to evaluate the impact of colloidal transport of hydrophobic organic contaminants. In Sweden alone, 400 to 500 sawmill sites are estimated to be contaminated with PCDD/Fs as a result of the former use of CP-based wood preservatives. The widespread use of CP mixtures for a variety of applications, including wood preservation, indicates that potential colloidal transport will be an issue of concern in many countries.     

Dynamics of carbon, nitrogen and hydrocarbons in diesel-contaminated soil amended with biosolids and maize

Contamination of soil with hydrocarbons occurs frequently when petroleum ducts are damaged. Restoration of those contaminated soils might be achieved by applying readily available organic material. An uncontaminated clayey soil sampled in the vicinity of a duct carrying diesel which ruptured recently, was contaminated in the laboratory and amended with or without maize or biosolids while production of carbon dioxide (CO(2)), dynamics of ammonia (NH(4)(+)), nitrates (NO(3)(-)), and total petroleum hydrocarbons (TPH) were monitored. The fastest mineralization of diesel, as witnessed by production of CO(2), was found when biosolids were added, but the amount mineralized after 100 days, approximately 88%, was similar in all treatments. Approximately 5 mg of the 48 mg TPH kg(-1) found in the sterilized soil at the beginning of the experiment could not be accounted for after 100 days. The concentration of TPH in the unsterilized soil decreased rapidly in all treatments, but the rate of decrease was different between the treatments. The fastest decrease was found in the soil amended with biosolids and approximately 30 mg TPH kg(-1) or 60% could not be accounted for within 7 days. The decrease in concentration of TPH at the onset of the incubation was similar in the other treatments. After 100 days, the concentration of TPH was similar in all soils and appear to stabilize at 19 mg TPH kg(-1) soil. It was concluded that biosolids accelerated the decomposition of diesel and TPH due to its large nutrient content, but after 100 days the amount of diesel mineralized and the residual concentration of TPH was not affected by the treatment applied.     

Speciation and mobility of cadmium in straw and wood combustion fly ash

Two fly ashes from biomass combustion have been analysed regarding cadmium speciation and mobility. A fly ash from straw combustion contained 10 mg Cd/kg dry matter, and around 50% of the cadmium was leachable in water. The possible main speciation of cadmium in this fly ash was CdCl2. When adding this fly ash to agricultural soil a threat for groundwater contamination and plant uptake is existing. A fly ash from wood chip combustion had 28.6 mg Cd/kg dry matter. In this fly ash, the cadmium was bound more heavily, with only small amounts of cadmium leached in mild extractants. A possible speciation of cadmium in this fly ash was as oxide or as CdSiO3. Long-term effects and accumulation of cadmium could be a problem when adding this fly ash to agricultural or forest soils.     

Distribution, origin and fate of chromium in soils in Guanajuato, Mexico

Total, hexavalent and trivalent chromium were determined in surface and 30-cm depth soil samples from a highly chromium-polluted area in Guanajuato state, central México. Four samples were also analyzed by a sequential extraction procedure. Nearly 0.9 km(2) out of the 8 km(2) area sampled was polluted with chromium, at concentrations up to 12960 mg kg(-1), mostly as Cr(III). Concentrations of Cr(VI) were lower than 0.5 mg kg(-1) in most sampled points, with the exception of one, where the concentration was found to be 65.14 mg kg(-1). Chromiumcontaining dust from a chromate factory accounted for most of the contamination. The highest concentrations of hexavalent chromium in soil, were in the bottom sediments of an abandoned water reservoir used to store polluted water from a well, before use of the water in the factory process. Tannery wastes, dust from a sanitary landfill of chromate compounds and the transport of chromium products are the sources of chromium at other sites. Chromium is fixed preferentially in the hydrous Fe and Mn oxides in the more polluted soils. Less polluted soils have a high proportion of chromium associated with the sulfide and organic fraction. Cr(III) is retained preferentially in the superficial soil layer. Variations in the physical characteristics of the soil, relative abundance of the various soil components and characteristics of the contaminant source, give rise to differences in chromium soil concentrations with depth.     

Dynamics of nitrogen in a PAHs contaminated soil amended with biosolid or vermicompost in the presence of earthworms

Nitrogen mineralization in PAHs contaminated soil in presence of Eisenia fetida amended with biosolid or vermicompost was investigated. Sterilized and unsterilized soil was contaminated with PAHs, added with E. fetida and biosolid or vermicompost and incubated aerobically for 70 days, while dynamics of inorganic N were monitored. Addition of E. fetida to sterilized soil increased concentration of NH(4)(+) 100> mg N kg(-1), while concentrations in unsterilized remained <60 mg N kg(-1) except for soil amended with biosolid plus PAHs where it increased to >80 mg kg(-1). Addition of PAHs had no significant effect on concentration of NH(4)(+) compared to the unamended soil, except in the soil added with biosolid. Addition of E. fetida to sterilized soil increased concentration of NO(2)(-) 15> mg N kg(-1) while concentrations in unsterilized soil remained <7.5 mg N kg(-1) except for soil amended with biosolid where it increased to >20 mg kg(-1). Addition of PAHs had no significant effect on concentration of NO(2)(-) compared to the unamended soil. Addition of biosolid and vermicompost increased concentration of NO(3)(-), while addition of E. fetida decreased concentration of NO(3)(-) in biosolid amended soil. It was found that NH(4)(+) and NO(2)(-) oxidizers were present in the gut of E. fetida, but their activity was not sufficient enough to inhibit a temporarily increase in concentrations of NH(4)(+) and NO(2)(-). Contamination with PAHs induced immobilization of N in biosolid or vermicompost amended soil, as did feeding of E. fetida on biosolid or vermicompost.     

U and Th in some brown coals of Serbia and Montenegro and their environmental impact

GOAL, SCOPE AND BACKGROUND: The objective of this paper is to determine and compare the concentrations of U and Th in soft to hard brown (lignite to sub-bituminous) coals of Serbia and Montenegro. It also presents comparison of the obtained data on U and Th concentrations with the published data on coals located in some other countries of the world. Almost the whole coal production of Serbia and Montenegro is used as feed coals for combustion in thermal power plants. METHODS: Channel samples from open pit and underground mines and core samples were collected for hard and soft brown coals. For the analysis the samples were decomposed using microwave technique. Obtained solutions containing U and Th were analyzed by inductively coupled plasma mass spectroscopy (ICP-MS) using NIST standards. RESULTS: Concentration of U from the investigated basins and the corresponding mine fields ranges within 0.60-70.10 mg/kg, 0.65-3.20 mg/kg, 0.95-6.59 mg/kg, 1.20-6.05 mg/kg, 0.80-6.66 mg/kg, 0.18-89.90 mg/kg, 0.19-4.14 mg/kg, and 0.28-3.52 mg/kg for the Kostolac, Kolubara, Krepoljin, Sjenica, Soko Banja, Bogovina East field, Senje-Resavica and Pljevlja basins, respectively. Concentration of Th ranges within 0.20-2.60 mg/kg, 0.84-6.57 mg/kg, 1.48-6.48 mg/kg, 0.12-2.71 mg/kg, 0.13-4.95 mg/kg, 0.14-3.48 mg/kg, 0.29-3.56 mg/kg, and 0.17-1.89 mg/kg for the Kostolac, Kolubara, Krepoljin, Sjenica, Soko Banja, Bogovina East field, Senje-Resavica and Pljevlja basins, respectively. DISCUSSION: Brown coal from Senje-Resavica, Kolubara, Kostolac and Pljevlja is characterized by low U concentration. Coals form the Krepoljin, Soko Banja and Sjenica basins have slightly higher U concentrations than the mentioned group. The highest concentration of U is characteristic for the coal from the Bogovina East field. Concentration of Th in coals from Serbia and Montenegro has proved to be low. Out of all investigated coal basins, only the coal from the Krepoljin and Kolubara basins has high concentration of Th. The hydrothermally altered rocks of the Timok dacite-andesite complex, representing the basement of the Bogovina basin, could be a potential source of U, especially at the bottom part of the Lower seam of the Bogovina East field. CONCLUSIONS: This study shows that brown coals in Serbia and Montenegro (soft to hard brown coals or lignite to sub-bituminous) contain low levels of U (5.30 mg/kg, average value and 2.10 mg/kg geometric mean value) and Th (1.80 mg/kg, average value and 1.12 mg/kg geometric mean value). There are some obvious differences in concentration of U and Th in coals from different basins in Serbia and Montenegro. The approximate value for U and Th release mainly from power plants was 644.33 t and 983.46 t, respectively within the period 1965-2000 for the studied mines in Serbia, and 23.76 t and 15.05 t for the Potrlica mine (Montenegro) within the period 1965-1997. RECOMMENDATIONS: The coals in Serbia and Montenegro show no identifiable unfavourable impact on the surrounding environment, due to low natural radioactive concentration of U and Th, but further investigations concerning human health should be performed. PERSPECTIVES: Preliminary research revealed that in some Serbian coals (and, particularly, parts of the coal seam) U and Th content are rather high. Such coals should be carefully studied, as well as U and Th concentrations in ash, fly ash, waste disposals, nearby soil and ground water. Further studies should include determination of the radioactivity of all these products, and estimation of possible health impact.     

Acute toxicity of chlorophenols to earthworms using a simple paper contact method and comparison with toxicities to fresh water organisms

An acute toxicity test of chlorophenols on earthworms (Eisenia fetida) was performed using a simple paper contact method proposed by OECD testing guideline no. 207, that were applied as an earthworm toxicity test. The median lethal concentration, EC50, had significant correlation with logP(ow) (1-octanol/water partition coefficient) of the chemicals. The toxicity of chlorophenols on E. fetida was compared with toxicities for other species: an algae (Selenostrum capricornutum), a crustacean (Daphnia magna), and a fish (Oryzias latipes). It was found that the toxicity of chlorophenols was almost same for E. fetida and for fresh water organisms. These results suggest the possibility of drawing correlations between the effects of pollutants on living things in different environments, fresh water and soil.     

Effects of compost and phosphate on plant arsenic accumulation from soils near pressure-treated wood

Leaching of arsenic (As) from chromated copper arsenate (CCA)-treated wood may elevate soil arsenic levels. Thus, an environmental concern arises regarding accumulation of As in vegetables grown in these soils. In this study, a greenhouse experiment was conducted to evaluate As accumulation by vegetables from the soils adjacent to the CCA-treated utility poles and fences and examine the effects of soil amendments on plant As accumulation. Carrot (Daucus carota L.) and lettuce (Lactuca sativa L.) were grown for ten weeks in the soil with or without compost and phosphate amendments. As expected, elevated As concentrations were observed in the pole soil (43 mg kg(-1)) and in the fence soil (27 mg kg(-1)), resulting in enhanced As accumulation of 44 mg kg(-1) in carrot and 32 mg kg(-1) in lettuce. Addition of phosphate to soils increased As accumulation by 4.56-9.3 times for carrot and 2.45-10.1 for lettuce due to increased soil water-soluble As via replacement of arsenate by phosphate in soil. However, biosolid compost application significantly reduced plant As uptake by 79-86%, relative to the untreated soils. This suppression is possibly because of As adsorbed by biosolid organic mater, which reduced As phytoavailability. Fractionation analysis showed that biosolid decreased As in soil water-soluble, exchangeable, and carbonate fraction by 45%, whereas phosphate increased it up to 2.61 times, compared to the untreated soils. Our results indicate that growing vegetables in soils near CCA-treated wood may pose a risk of As exposure for humans. Compost amendment can reduce such a risk by reducing As accumulation by vegetables and can be an important strategy for remediating CCA-contaminated soils. Caution should be taken for phosphate application since it enhances As accumulation.     

Field-scale leaching of arsenic, chromium and copper from weathered treated wood

Earlier studies documented the loss of wood preservatives from new wood. The objective of this study was to evaluate losses from weathered treated wood under field conditions by collecting rainfall leachate from 5 different wood types, all with a surface area of 0.21 m². Wood samples included weathered chromate copper arsenate (CCA) treated wood at low (2.7 kg/m³), medium (4.8 kg/m³) and high (35.4 kg/m³) retention levels, new alkaline copper quat (ACQ) treated wood (1.1 kg/m³ as CuO) and new untreated wood. Arsenic was found to leach at a higher rate (100 mg in 1 year for low retention) than chromium and copper (<40 mg) in all CCA-treated wood samples. Copper leached at the highest rate from the ACQ sample (670 mg). Overall results suggest that metals' leaching is a continuous process driven by rainfall, and that the mechanism of release from the wood matrix changes as wood weathers.