Organic pollutants in compost and digestate. Part 1. Polychlorinated biphenyls, polycyclic aromatic hydrocarbons and molecular markers

In Europe, 9.3 x 10(6) t(dry weight (dw)) of compost and digestate are produced per year. Most of this is applied to agricultural land, which can lead to considerable inputs of organic pollutants, such as polychlorinated biphenyls (PCB) and polycyclic aromatic hydrocarbons (PAH) to soil. This paper presents an inventory of the pollutant situation in source-separated composts, digestates and presswater in Switzerland by a detailed analysis of over 70 samples. PCB concentrations ( summation PCB 28, 52, 101, 118, 138, 153, 180) were significantly higher in urban (median: 30 microg kg(-1)dw, n = 52) than in rural samples (median: 14 microg kg(-1)dw, n = 16). Together with low concentrations in general, this points to aerial deposition on compost input material as the major contamination pathway. Enantiomeric fractions of atropisometric PCB were close to racemic. Median PAH concentration was 3010 microg kg(-1)dw( summation 15PAH, n = 69), and one quarter of the samples exhibited concentrations above the relevant Swiss guide value for compost (4000 microg kg(-1)dw). The levels were influenced by the treatment process (digestate > compost), the season of input material collection (spring-summer > winter > autumn), the particle size (coarse-grained > fine-grained), and maturity (mature > less mature). The main source of PAH in compost was pyrogenic, probably influenced mainly by liquid fossil fuel combustion and some asphalt abrasion, as suggested by multiple linear regression. This study, together with a companion paper reporting on other organic contaminates including emerging compound classes, provides a starting point for a better risk-benefit estimation of the application of compost and digestate to agricultural soil in Switzerland.     

Organic pollutants in compost and digestate. Part 2. Polychlorinated dibenzo-p-dioxins, and -furans, dioxin-like polychlorinated biphenyls, brominated flame retardants, perfluorinated alkyl substances, pesticides, and other compounds

Compost and digestate are important recycling fertilizers and have beneficial effects on soil parameters. However, they can contain significant amounts of organic pollutants. Here, the first comprehensive data set on dibenzo-p-dioxins and -furans (PCDD/F), dioxin-like polychlorinated biphenyls (DL-PCB), brominated flame retardants, perfluorinated alkyl substances (PFAS), pesticides, phthalates, nonylphenol and chlorinated paraffins (CP) in source-separated compost and digestate from Switzerland is presented (n = 3-18). The median summation 17PCDD/F and summation 12DL-PCB concentrations were at 3.2 ng I-TEQ kg(-1)dry weight (dw) and 3.0 ng WHO-TEQ kg(-1)dw, respectively. Brominated diphenyl ether 209 (BDE 209) accounted for 72% of the total polyBDE content (10 microg kg(-1)dw). Hexabromocyclododecane (HBCD) and tetrabromobisphenol A (TBBPA) levels were at 100 and 0.51 microg kg(-1)dw, respectively. PFAS were identified for the first time in compost and digestate (median concentration 6.3 microg kg(-1)dw, summation 21compounds). Out of 269 pesticides analysed, 30 fungicides, 14 herbicides, eight insecticides and one acaricide were detected. Di-(2-ethylhexyl)phthalate (DEHP) median concentration accounted for 280 microg kg(-1)dw and nonylphenol was below the detection limit of 1 mg kg(-1)dw. The sum of short and medium chain CP was between 90 and 390 microg kg(-1)dw. The concentrations observed were at or above the levels found in background soils, which are the main recipient of compost and digestate. Where actually applied, compost can contribute considerably to the total input of organic pollutants to the soil. However, on a total Swiss agricultural area base, inputs seem to be limited.     

Environmental contaminants in male river otters from Oregon and Washington, USA, 1994–1999

This study reports hepatic concentrations and distribution patterns of select metals, organochlorine pesticides (OCs), polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in 180 male river otters (Lontra canadensis) collected from Oregon and Washington, 1994-1999. Seven regional locations of western Oregon and Washington were delineated based on associations with major population centers, industry or agriculture. Cadmium (Cd) was not found above 0.5 microg g(-1), dry weight (dw) in juveniles, but increased with age in adults though concentrations were generally low (nd-1.18 microg g(-1), dw). Regional geometric means for total mercury (THg) ranged from 3.63 to 8.05 microg g(-1), dw in juveniles and 3.46-12.6 microg g(-1) (dw) in adults. The highest THg concentration was 148 microg g(-1), dw from an apparently healthy adult male from the Olympic Peninsula of Washington. Although THg increased with age in adult otters, the occurrence of the more toxic form methylmercury (MeHg) was not evaluated. Mean OC and PCB concentrations reported in this study declined dramatically from those reported in 1978-1979 from the lower Columbia River. Organochlorine pesticide and metabolite means for both juvenile and adult river otter males were all below 100 microg kg(-1), wet weight (ww), with only DDE, DDD and HCB having individual concentrations exceeding 500 microg kg(-1), ww. Mean SigmaPCB concentrations in both juvenile and adult male otters were below 1 microg g(-1) for all regional locations. Mean juvenile and adult concentrations of non-ortho substituted PCBs, PCDDs and PCDFs were in the low ng kg(-1) for all locations studied.     

Occurrence of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in Lake Maggiore (Italy and Switzerland)

Samples of air (gas and particulate phases), bulk deposition, aquatic settling material and sediments were collected in Lake Maggiore (LM) in order to determine their content of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs). Air (gas and particulate phases) concentrations were 0.5 pg m(-3), 80 pg m(-3), 13 pg m(-3) and 106 pg m(-3) for SigmaPCDD/Fs, SigmaPCBs, Sigma dioxin-like PCBs (DL-PCBs) and SigmaPBDEs, respectively. Deposition fluxes ranged from 0.7 ng m(-2) d(-1) for SigmaPCDD/Fs to 32 ng m(-2) d(-1) for SigmaPCBs. Aquatic settling material presented concentrations of 0.4 ng g(-1) dry weight (dw) for SigmaPCDD/Fs, 13 ng g(-1) dw for SigmaPCB, 3.4 ng g(-1) dw for SigmaDL-PCBs and 5.7 ng g(-1) dw for SigmaPBDEs. Mean sediment concentrations were 0.4 ng g(-1) dw for SigmaPCDD/Fs, 11 ng g(-1) dw for SigmaPCB, 3 ng g(-1) dw for SigmaDL-PCBs and 5.1 ng g(-1) dw for SigmaPBDEs. Similar PCDD/F and DL-PCB congener patterns in all the environmental compartments of LM point to an important, if not dominant, contribution of atmospheric deposition as source of these pollutants into LM. In contrast, PBDE congener distribution was not similar in the different environmental compartments. BDE 47 dominated air and settling material, while BDE 209 was the predominant congener in the bulk atmospheric deposition. Moreover, sediments showed two distinct PBDE congener profiles. Lower PBDE concentrated sediments were dominated by congeners 47 and 99, while BDE 209 dominated in higher PBDE concentrated samples. This suggests the influence of local sources as well as atmospheric input of PBDEs into LM.     

Environmental contaminants in Canadian shorebirds

Canadian shorebirds are exposed to environmental contaminants throughout their annual cycle. Contaminant exposure among species varies with diet, foraging behaviour and migration patterns. We sampled twelve species of shorebirds from four locations across Canada to assess their exposure to PCBs, organochlorine pesticides, as well as four trace elements (Hg, Se, Cd, As). SigmaPCB and SigmaDDT followed by SigmaCHL were most frequently found above trace level in the shorebird carcasses. In general, the plover species (American golden, semipalmated, black-bellied) appear to be the most contaminated with organochlorines, whereas Hudsonian and marbled godwits appear to be the least contaminated. Among adult birds, the greater and lesser yellowlegs had the highest hepatic Hg concentrations (2.4-2.7 microg g(-1) dw), whereas American golden plovers as well as Hudsonian and marbled godwits contained relatively low levels of Hg (<1 microg g(-1) dw). Renal Se concentrations varied from 3.2 to 16.7 microg g(-1) dw and exhibited little interspecific or seasonal variation. Renal Cd levels in adult birds were highest in Hudsonian godwits from Quill Lakes (43 microg g(-1) dw) and Cape Churchill (12 microg g(-1) dw), and lowest (0.8-1.5 microg g(-1) dw) in greater and lesser yellowlegs from Cape Churchill and Bay of Fundy. Renal As concentrations varied from 0.06 microg g(-1) dw in golden plovers from Cape Churchill to 4.6 and 5.1 microg g(-1) dw in dunlin samples from the Pacific coast. There is no evidence that contaminants were adversely affecting the shorebirds sampled from the Canadian locations in this study.     

Persistent organic pollutants in sediment from the southern Baltic: risk assessment

The concentrations of organochlorine pesticides, PCBs, and PCDD/Fs were measured in sediment samples collected from the Gulf of Gdańsk, the Gdańsk Deep, the Vistula Lagoon and the off-shore waters in the southern Baltic Sea. The determinations were conducted in the fraction <63 μm. The highest levels of pollutants were found in sediments from the Gulf of Gdańsk and the Gdańsk Deep. In these sediments, concentrations of pp'-DDT and its metabolites (pp'-DDE and pp'-DDD) ranged from 2 to 11 μg kg(-1) dw. Concentrations of HCB were between 0.1 and 1.0 μg kg(-1) dw. Concentrations of the sum of α-, β-, γ-HCH were between 0.3 and 2.58 μg kg(-1) dw. Concentrations of marker PCBs ranged from about 2 to 11 μg kg(-1) dry weight. Total TEQ PCDD/F/dl-PCB values in the studied samples varied between 1 and 18 ng kg(-1) dw. The data were evaluated in terms of ecotoxicological criteria based on the environmental impact of the pollutant effects. Our research indicated that in the sediment from the southern Baltic Sea, the PCDD/F and PCBs occurred at concentrations which could be dangerous to marine organisms.     

Preliminary assessment of polybrominated diphenyl ethers (PBDEs) in the Scottish aquatic environment, including the Firth of Clyde

This paper presents preliminary data on polybrominated diphenyl ethers (PBDEs) in the Scottish aquatic environment. Sediment and biota (fish liver, fish muscle and mussels) from a number of locations around Scotland were analysed for PBDEs with samples being from both remote and from potentially contaminated areas such as the former sewage sludge dump site at Garroch Head in the Clyde. PBDEs were measured in both cultivated, rope grown mussels and wild mussels collected from 5 sites around Scotland in 2006. Total PBDE concentrations (sum of tri- to hepta-BDEs) ranged from 相似文献   

Wetland soil and vegetation bismuth content following experimental deposition of bismuth pellets

Bismuth pellets have been approved as a non-toxic alternative to lead pellets in Canada since 1997 but, to our knowledge, there is little literature for soil and vegetation bismuth content in areas of bismuth pellet deposition. The present study addresses this shortcoming by measuring wetland soil and vegetation bismuth content following experimental deposition of bismuth pellets under ambient and experimentally increased acidic deposition conditions. We manipulated 24 plots in a fully factorial design (bismuth shot x soil acidification) in a south-eastern Ontario freshwater wetland during 1999-2003. Soil pH (range 6.5-7.3) increased significantly (p = 0.001) during the experimental period but there were no significant differences amongst treatments (p = 0.79). Significantly (p < 0.05) greater bismuth concentrations were measured in soil receiving bismuth pellets (mean +/- SE, n = 6; with acidification = 2.55 +/- 1.02 microg Bi g(-1) dry mass [DM]; without acidification = 6.40 +/- 2.23 microg Bi g(-1) DM) compared to plots that were not seeded with bismuth pellets (without acidification = 0.42 +/- 0.09 microg Bi g(-1) DM; with acidification = 0.39 +/- 0.10 microg Bi g(-1) DM). Nevertheless, bismuth levels in 20 of 24 aboveground tissue samples from the Carex lacustris-Agrostis scabra community were below detection levels (0.057 microg Bi g(-1) DM); the other samples ranged from 0.065 to 0.095 microg Bi g(-1) DM, similar to global background levels. Primary productivity in plots receiving bismuth pellets and soil acidification was not significantly (p = 0.15) different to vegetation in plots that were not manipulated. The results suggest bismuth mobilization from bismuth pellets into soil but not to aboveground vegetation.     

Quantification and source identification of polycyclic aromatic hydrocarbons in sediment, soil, and water spinach from Hanoi, Vietnam

Polycyclic aromatic hydrocarbons (PAHs) were quantified in sediment, soil, and plant material from Hanoi, Vietnam, and an aquatic production system in peri-urban Hanoi. The sum of the concentration of 16 US-EPA priority PAHs ( summation PAH16) ranged between 0.44 and 6.21 mg kg(-1) dw in sediment and between 0.26 and 1.35 mg kg(-1) dw in soil, with decreasing concentrations from the urban area to the peri-urban area, indicating contributions from urban and industrial sources. Double plots of diagnostic source ratios indicate that PAHs originate from mixed petrogenic and pyrogenic sources, the latter being predominant. The predominance of low molecular weight (LMW) PAHs in the sediment samples suggests that petrogenic sources are more prevalent in the water environment than in the soil. In contrast, high molecular weight (HMW) PAHs dominated in water spinach which probably reflects the plant's uptake of particle-bound PAHs that originate from pyrogenic sources.     

Atmospheric deposition of major ions and trace metals near an industrial area,Jordan

Al, Cd, Cr, Cu, Fe, Mn, Pb, Zn, NH4+, Mg2+, Ca2+, Na+, K+, Cl-, NO3- and SO4(2-), along with pH were determined in wet and dry deposition samples collected at Al-Hashimya, Jordan. Mean trace metal concentrations were similar or less than those reported for other urban regions worldwide, while concentrations of Ca2+ and SO4(2-) were the highest. The high Ca2+ concentrations were attributed to the calcareous nature of the local soil and to the influence of the Saharan dust, while the high concentrations of SO4(2-) were attributed to the influence of anthropogenic sources and Saharan dust soil. Except for SO4(2-), NO3-, and Ca2+, dry deposition fluxes of measured metals and ions were higher than their corresponding wet deposition fluxes. The high annual average pH values recorded for wet and dry deposition samples were attributed to the neutralization of acidity by alkaline species. Cd, Cr, Cu, Pb, Zn, NO3- and SO4(2-) were enriched in wet and dry deposition samples relative to crustal material, and a significant anthropogenic contribution to these elements and ions is tentatively suggested. Finally, the possible sources and the main factors affecting the concentrations of the measured species are discussed.     

DBP Levels in Chlorinated Drinking Water: Effect of Humic Substances

Chlorination is the most widely used technique for disinfection of drinking water. A consequence of chlorination is the formation of Disinfection By-Products (DBPs). The formation of DBPs in drinking water results from the reaction of chlorine with naturally occurring organic materials, principally humic and fulvic acids. This paper focuses on the effect of humic substances on the formation of twenty-four compounds belonging to different categories of DBPs. This investigation was conducted in two water treatment plants in Greece, Menidi and Galatsi, from July 1999 to April 2000. Humic substances were determined by the diethylaminoethyl (DEAE) method with subsequent UV measurement. The techniques used for the determination of DBPs were liquid-liquid extraction, gas chromatography and mass spectrometry. The concentrations of DBPs were generally low. Total trihalomethanes (TTHMs) ranged from 5.1 to 24.6 microg L(-1), and total haloacetic acids (HAAs) concentration ranged from 8.6 to 28.4 microg L(-1), while haloaketones (HKs) and chloral hydrate (CH) occurred below 1 microg L(-1). The content of humic substances was found to influence the formation of DBPs and especially TTHMs, trichloroacetic acid (TCA), dibromoacetic acid (DBA), CH, 1,1-dichloropropanone (1.1-DCP) and 1,1,1-trichloropropanone (1,1,1-TCP). Seasonal variation of TTHMs and HAAs generally followed that of humic substances content with peaks occurring in autumn and spring. The trends of 1,1-DCP, 1,1,1-TCP and CH formation seemed to be in contrast to TTHMs and HAAs. Trends of formation of individual compounds varied in some cases, probably due to influence of parameters other than humic substances content. Statistical analysis of the results showed that the concentrations of TTHMs, CH, 1,1-DCP, 1,1,1-TCP, TCA and DBA are strongly affected from humic substances content (at 0.01 confidence level). The opposite is true for dichloroacetic acid (DCA) concentration. Humic substances also vary to a statistically significant degree during different months, as well as the concentrations of TTHMs, CH, 1,1-DCP, 1,1,1-TCP, TCA and DCA. The variance of DBA was not statistically significant. Regarding the effect of sampling station, humic substances content showed no statistically significant difference between the two raw water sources studied.     

Bio-monitoring for uranium using stream-side terrestrial plants and macrophytes

This study evaluated the abilities of various plant species to act as bio-monitors for environmental uranium (U) contamination. Vegetation and soil samples were collected from a U processing facility. The water-way fed from facility storm and processing effluents was the focal sample site as it represented a primary U transport mechanism. Soils and sediments from areas exposed to contamination possessed U concentrations that averaged 630 mg U kg(-1). Aquatic mosses proved to be exceptional accumulators of U with dry weight (dw) concentrations measuring as high as 12,500 mg U kg(-1) (approximately 1% of the dw mass was attributable to U). The macrophytes (Phragmites communis, Scripus fontinalis and Sagittaria latifolia) were also effective accumulators of U. In general, plant roots possessed higher concentrations of U than associated upper portions of plants. For terrestrial plants, the roots of Impatiens capensis had the highest observed levels of U accumulation (1030 mg kg(-1)), followed by the roots of Cyperus esculentus and Solidago speciosa. The concentration ratio (CR) characterized dry weight (dw) vegetative U levels relative to that in associated dw soil. The plant species that accumulated U at levels in excess of that found in the soil were: P. communis root (CR, 17.4), I. capensis root (CR, 3.1) and S. fontinalis whole plant (CR, 1.4). Seven of the highest ten CR values were found in the roots. Correlations with concentrations of other metals with U were performed, which revealed that U concentrations in the plant were strongly correlated with nickel (Ni) concentrations (correlation: 0.992; r-squared: 0.984). Uranium in plant tissue was also strongly correlated with strontium (Sr) (correlation: 0.948; r-squared: 0.899). Strontium is chemically and physically similar to calcium (Ca) and magnesium (Mg), which were also positively-correlated with U. The correlation with U and these plant nutrient minerals, including iron (Fe), suggests that active uptake mechanisms may influence plant U accumulation.     

Nitrate Leaching by Atmospheric N Deposition to Upper Groundwater in the Sandy Regions of The Netherlands in 1990

Anthropogenic increase in atmospheric nitrogen (N) deposition in nature areas results in nitrate leaching to groundwater, threatening its quality. Member states of the European Union are obliged to reduce groundwater nitrate concentrations and to monitor this reduction. The relationship between N deposition and groundwater nitrate concentrations is quantified using a field survey and geographical information. Nitrate concentrations of the uppermost metre of groundwater in nature areas in the sandy regions in 1990 were related to geographical data by means of regression analysis. In this way nitrate concentrations could be explained by potential ammonia deposition, soil type, vegetation and land use. We found that about 35% of 54 kg ha(-1) a(-1) atmospheric N deposition was leached to the upper groundwater as nitrate, resulting in a mean NO3 concentration of about 30 mg L(-1). The critical N load for exceeding the EC limit value (50 mg L(-1)) in the sandy regions of The Netherlands composed of natural vegetation will be about 80 kg ha(-1) a(-1). Leaching is less than expected for nature areas but comparable with leaching of N surpluses in pastures in The Netherlands. A reduction in nitrate leaching by 25% or more can currently be detected via a new field survey.     

Concentrations and inventories of polycyclic aromatic hydrocarbons and organochlorine pesticides in watershed soils in the Pearl River Delta,China

The concentration levels, source, and inventories of polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs) in 55 surface vegetable soils in the watershed of the Pearl River Delta (PRD) were analyzed and compared with those of the surface sediments in the Pearl River Estuary (PRE) and northern South China Sea (SCS). The 16 priority PAHs on US EPA list range from 58 to 3,077 microg/kg (average: 315 microg/kg). The concentrations of DDTs and HCHs range from 3.58 to 831 microg/kg (average: 82.1 microg/kg) and from 0.19 to 42.3 microg/kg (average: 4.42 microg/kg). The ratios of DDT/ (DDD+DDE) are higher than 2 in majority of the soil samples, suggesting that DDT contamination still exists. The PAH ratios suggest that the source of PAHs is petroleum, and combustion of fossil fuel, biomass, and coal. The average concentrations of PAHs and the linear regression slope between PAHs and TOC for the soils and the sediments are quite similar. It was estimated that the soil mass inventories at 0-20 cm depth are 1,292 metric tons for PAHs and 356 metric tons for OCPs in the studied region. The average PAHs inventory per unit area for the soil samples investigated in PRD is about 0.86 time that of surface sediments in the Pearl River Estuary, and about 2.43 times that of surface sediments in the northern South China Sea. PAHs in the soils in PRD have similar source to those of the surface sediments in PRE. All of those may suggest that PAHs in PRE and SCS are probably mainly inputted from the soils in PRD via soil erosion and river transport.     

Description and evaluation of a sampling system for monitoring hydrocarbons in sediments

A composite random sampling design was used to estimate the concentrations of hydrocarbons in sediments from two near-shore areas of Scotland (Firth of Clyde and Firth of Forth). The aim of this work was to estimate a mean value for each parameter in these areas, and to determine whether this can be done with more thorough coverage (better representation), better precision and less variance at lower analytical cost through a composite random sampling scheme rather than a simple random sampling scheme, and thereby contribute to the re-design of the UK National Marine Monitoring Programme (NMMP), re-named the UK Clean Seas Environmental Monitoring Programme (CSEMP) in 2006. Samples were collected using a simple random sampling design during 2005. All sediment samples were analysed for their particle size distribution and total organic carbon (TOC). All sediments were analysed for polycyclic aromatic hydrocarbons (PAHs) and n-alkanes. The concentrations of PAHs and n-alkanes in the study areas are described, and sources of PAHs were investigated through the PAH distributions and n-alkane profiles. Individual sediment samples from each area were combined to give a series of composite sub-samples, each comprised of 5 individual sediment samples. These composite samples were re-analysed for the same parameters as the individual samples. Mean total PAH (2- to 6-ring parent and branched) concentrations, based on the individual original sediment samples collected through simple random sampling, were 1858 microg kg(-1) dry weight (SE = 196 microg kg(-1) dry weight, n = 25) and 532.4 microg kg(-1) dry weight (SE = 59 microg kg(-1) dry weight, n = 25) in the Clyde and Forth, respectively. Mean total PAH concentrations of the composite samples were 1745 microg kg(-1) dry weight (SE = 121.0 microg kg(-1) dry weight, n = 5) in the Clyde and 511.6 microg kg(-1) dry weight (SE = 37.4 microg kg(-1) dry weight, n = 5) in the Forth. No significant differences were found between the mean PAH concentrations from the two sampling designs. This study demonstrated that the composite random sampling design gave a mean value with less variance than the simple random sampling design, at significantly reduced analytical effort (and cost).     

Addressing analytical uncertainties in the determination of trichloroacetic acid in soil

Soil is an important compartment in the environmental cycling of trichloroacetic acid (TCA), but soil TCA concentration is a methodologically defined quantity; analytical methods either quantify TCA in an aqueous extract of the soil, or thermally decarboxylate TCA to chloroform in the whole soil sample. The former may underestimate the total soil TCA, whereas the latter may overestimate TCA if other soil components (e.g. humic material) liberate chloroform under the decarboxylation conditions. The aim of this work was to show that extraction and decarboxylation methods yield different TCA concentrations because the decarboxylation method can also determine "bound" TCA. Experiments with commercial humic acid solutions showed there was no additional chloroform formation under decarboxylation conditions, and that all TCA in a TCA-humic acid mixture could be quantitatively determined (108 +/- 13%). Anion exchange resin was used as a provider of solid-phase TCA binding; only 5 +/- 1% of a TCA solution mixed with the resin was present in the aqueous extract subsequently separated from the resin, yet the decarboxylation method yielded mass balance (123 +/- 22%) with TCA remaining in the resin. In aqueous extraction of a range of soil samples (with or without added TCA spike), the decarboxylation method was able to satisfactorily account for TCA in the extractant + residue post-extraction, compared with whole-soil TCA (+ spike) pre-extraction: e.g. mass balances for unspiked soil from Sikta spruce and larch forest were 99 +/- 8% and 93 +/- 6%, respectively, and for TCA-spiked forest and agricultural soils were 114 +/- 13% and 102 +/- 2%. In each case recovery of TCA in the extractant was substantially less than 100%(<20% for unspiked soils, <55% for spiked soils). Extraction efficiencies were generally lower in more organic soils. The results suggest that analytical methods which utilise aqueous extraction may underestimate whole-soil TCA concentrations. Application of both methodologies together may enhance insight into TCA behaviour in soil.     

Total mercury determination in sand boxes from Montreal

Direct mercury analysis was successfully applied to determine trace levels of total mercury in samples from sand boxes in Montréal (Québec, Canada). Twenty sand boxes were sampled from across the city and divided into two size fractions, a fine fraction (<100 microm) and a whole fraction. The concentrations of mercury ranged from 1.6 to 35 microg Hg kg(-1) dry soil for the fine fraction and from 0.7 to 6 microg Hg kg(-1) dry soil for the whole fraction. The mercury concentrations correlated with the soil organic carbon content (R2= 0.67) in the sand. The ratio of the concentration of mercury in the fine over the whole fraction varied from 2.2 to 18. Using published soil ingestion rates for children, the calculated daily intake values varied from 0 to 0.5 ng Hg kg(-1) bw d(-1) with an estimated oral ingestion of 200 mg of sand and from 0.2 to 4.7 ng Hg kg(-1) bw d(-1) with an ingestion of 1750 mg of sand. None of the sand boxes contain sufficient amounts of mercury so as to exceed the currently accepted daily intake threshold of 0.105 microg Hg kg(-1) bw d(-1) established by Health Canada.     

Atmospheric inorganic nitrogen deposition to a typical red soil forestland in southeastern China

A 2-year monitoring study was conducted to estimate nitrogen deposition to a typical red soil forestland in southeastern China. The dry deposition velocities (V(d)) were estimated using big leaf resistance analogy model. Atmospheric nitrogen dry deposition was estimated by combing V(d) and nitrogen compounds concentrations, and the wet deposition was calculated via rainfall and nitrogen concentrations in rainwater. The total inorganic nitrogen deposition was 83.7 kg ha(-1) a(-1) in 2004 and 81.3 kg ha(-1) a(-1) in 2005, respectively. The dry deposition contributed 78.6% to total nitrogen deposition, in which ammonia was the predominant contributor that accounted for 86.1%. Reduced nitrogen compounds were the predominant contributors, accounting for 78.3% of total nitrogen deposition. The results suggested that atmospheric inorganic nitrogen could be attributed to intensive agricultural practices such as excessive nitrogen fertilization and livestock production. Therefore, impacts of atmospheric nitrogen originated from agriculture practices on nearby forest ecosystems should be evaluated.     

Assessment of PAH pollution in the southern Baltic Sea through the analysis of sediment, mussels and fish bile

The concentrations of fifteen PAH compounds in samples of sediment and blue mussel tissue (Mytilus trossulus) were measured. In addition, the biliary polycyclic aromatic hydrocarbon metabolites present in flounder (Platichthys flesus) were analysed. Two methods were used in the analysis of PAH metabolites; high performance liquid chromatography (HPLC) and fixed wavelength fluorescence (FF). The major PAH metabolite which could be measured using the HPLC method was 1-OH pyrene. It was possible to detect 1-OH Phe and 3-OH B[a]P in 70 and 24 samples respectively, of the 87 samples analysed. However, the concentrations of 1-OH Phe and 3-OH B[a]P were below or near to the LOQ (0.002 μg ml(-1) bile). The bile of flounder samples from the Gulf of Gdańsk had 1-OH Pyr concentrations which ranged from 0.019 to 0.066 μg ml(-1) bile. The high linear correlation observed between the quantity of 1-OH pyrene determined by the HPLC-F method and the content of the sum of pyrene-type PAHs obtained by the FF method indicated the FF method of determination of pyrene-type PAH metabolites can be used as a screening method. The content of ∑(15)PAHs in sediments collected in the Gulf of Gdansk, in 2008, ranged from 29.3 to 103 μg kg(-1) dw. In mussel tissue ∑(15)PAHs concentrations were between 173.2 μg kg(-1) dw and 237.7 μg kg(-1) dw. All concentrations measured in the current study, in mussel tissue, were below the OSPAR toxicity threshold values.     

Vertical distribution of polycyclic aromatic hydrocarbons (PAHs) in Hunpu wastewater-irrigated area in northeast China under different land use patterns

The concentrations of polycyclic aromatic hydrocarbons (PAHs) were determined in groundwater and soil profiles from upland field and paddy field in the Hunpu wastewater-irrigated area of northeast China. In the study area, the peak concentrations of total PAHs were within or just below the topsoil, and the contents decline with depth at various trend verified by the Spearman's rank correlation test. The total PAH concentrations in upland soil layers ranged from 46.8 to 2,373.0 microg/kg (dry wt.), while the concentrations in paddy soil layers ranged from 23.1 to 1,179.1 microg/kg (dry wt.). The 16 priority PAHs were all detected in the analyzed soil samples, and naphthalene (Nap), phenanthrene (Phe), fluoranthene (Fla), chrysene (Chr), and benzo[a]pyrene (Bap) were selected for further study in terms of their vertical distributions. The concentrations of both total and individual PAHs in upland soil were generally higher than those in the corresponding layers of paddy soil. The concentrations of total and individual PAH were notably different between the corresponding horizons in upland and paddy soil were probably attribute to the different sources and properties of the PAHs and soil; different methods of soil tillage and plant growing. Special PAH compound ratios, such as phenanthrene/anthracene, fluoranthene/pyrene, LMW/HMW, and parent PAH ratios (Ant/178, Fla/202, BaA/228, and Ilp/276) were used to identify the source of soil PAHs. The data suggests that the possible sources of PAHs in the Hunpu wastewater-irrigation area are the incomplete combustion of coal, petroleum and crude oil, automobile exhausts. These sources lead to pollution of the soil and groundwater by wet/dry deposition and vertical downward migration.