Passive air sampling of PCBs, PBDEs, and organochlorine pesticides across Europe

Selected organochlorine pesticides in the atmosphere of major Indian cities: levels, regional versus local variations, and sources

India has extensive production and usage of organochlorine pesticides (OCPs) for agriculture and vector control. Despite this, few data are available on the levels and distribution of OCPs in the urban atmosphere of India. Passive and active air sampling was therefore conducted between Dec 2006 and March 2007 in 7 metropolitan cities: New Delhi, Kolkata, Mumbai, Chennai, Bangalore, Goa, and Agra. Concentrations (pg·m(-3)) were as follows: HCHs 890-17000 (mean: 5400 ± 4110); DDTs 250-6110 (1470 ± 1010); chlordanes 290-5260 (1530 ± 790); endosulfans 240-4650 (1040 ± 610); and hexachlorobenzene 120-2890 (790 ± 510). HCHs observed in India appear to be the highest reported across the globe. Chlordanes and endosulfans are lower than levels reported from southern China. Passive sampling enabled within- and between-city variations to be assessed. As expected, paired-sample t-test analysis revealed higher regional than local variation. Comparisons with the limited data available from studies conducted in 1989 suggest general declines of HCHs and DDTs for most regions. γ-HCH dominated the HCH signal, reflecting widespread use of Lindane in India, although the isomeric composition in Kolkata suggests potential technical HCH use. High o,p'-/p,p'-DDT ratios in northern India indicate recent DDT usage. High HCB levels in the industrial areas of New Delhi and Kolkata indicate ongoing sources. Correlation between trans- and cis-chlordane implies ongoing usage. Endosulfan sulfate generally dominated the endosulfan signal, but high values of α/β-endosulfan at Chennai, Mumbai and Goa suggest ongoing usage. Backward trajectories were computed using the NOAA HYSPLIT model to trace the air mass history. Result shows local/regional sources of OCPs within India.

Brominated flame retardants (BFRs) in air and dust from electronic waste storage facilities in Thailand

This study reports concentrations of brominated flame retardants in dust samples (n=25) and in indoor (n=5) and outdoor air (n=10) (using PUF disk passive air samplers) from 5 electronic and electrical waste (e-waste) storage facilities in Thailand. Concentrations of Sigma(10)PBDEs (BDEs 17, 28, 47, 49, 66, 85, 99, 100, 153 and 154) in outdoor air in the vicinity of e-waste storage facilities ranged from 8 to 150 pg m(-3). Indoor air concentrations ranged from 46 to 350 pg m(-3), with highest concentrations found in a personal computer and printer waste storage room at an e-waste storage facility. These are lower than reported previously for electronic waste treatment facilities in China, Sweden, and the US. Concentrations of Sigma(21)PBDEs (Sigma(10)PBDEs+BDEs 181, 183, 184, 191, 196, 197, 203, 206, 207, 208 and 209), decabromodiphenylethane (DBDPE), decabromobiphenyl (BB-209) in dust were 320-290,000, 43-8700 and <20-2300 ng g(-1) respectively, with the highest concentrations of Sigma(21)PBDEs, BDE-209 and DBDPE in a room used to house discarded TVs, stereos and radios. PBDE concentrations in dust were slightly higher but within the range of those detected in workshop floor dust from an e-waste recycling centre in China. The highest concentration of BB-209 was detected in a room storing discarded personal computers and printers. Consistent with recent reports of elevated ratios of BDE-208:BDE-209 and BDE-183:BDE-209 in household electronics from South China, percentage ratios of BDE-208:BDE-209 (0.64-2.9%) and of BDE-208:BDE-183 (2.8-933%) in dust samples exceeded substantially those present in commercial deca-BDE and octa-BDE formulations. This suggests direct migration of BDE-208 and other nonabrominated BDEs from e-waste to the environment. Under realistic high-end scenarios of occupational exposure to BDE-99, workers in the facilities were exposed above a recently-published Health Based Limit Value for this congener. Reassuringly, estimated exposures to BDE-209 were below the USEPA's reference dose for this congener.

A GIS model-based assessment of the environmental distribution of gamma-hexachlorocyclohexane in European soils and waters

The MAPPE GIS based multimedia model is used to produce a quantitative description of the behaviour of gamma-hexachlorocyclohexane (gamma-HCH) in Europe, with emphasis on continental surface waters. The model is found to reasonably reproduce gamma-HCH distributions and variations along the years in atmosphere and soil; for continental surface waters, concentrations were reasonably well predicted for year 1995, when lindane was still used in agriculture, while for 2005, assuming severe restrictions in use, yields to substantial underestimation. Much better results were yielded when same mode of release as in 1995 was considered, supporting the conjecture that for gamma-HCH, emission data rather that model structure and parameterization can be responsible for wrong estimation of concentrations. Future research should be directed to improve the quality of emission data. Joint interpretation of monitoring and modelling results, highlights that lindane emissions in Europe, despite the marked decreasing trend, persist beyond the provisions of existing legislation.

Trends in European background air reflect reductions in primary emissions of PCBs and PBDEs

Data are presented for polychlorinated biphenyls (PCBs) and polybrominated diphenyls ethers (PBDEs) in passive air samplers (PAS) collected along a rural/remote latitudinal transect from southern UK to northern Norway during 2004-2008. This study is part of an ongoing campaign, using semipermeable membrane devices (SPMDs) as PAS over two year intervals since 1994. Absolute sequestered amounts of selected PCB congeners have decreased in a first order fashion between 1994-2008, with the average time of 8.4+/-3.2 years for atmospheric concentrations to decline by 50%. PCBs have continued to fractionate with latitude during this period. PBDE concentrations declined by 50% between 2000 and 2008 every 2.2+/-0.4 years. Results are discussed in terms of sources, long-range atmospheric transport, global fractionation, and clearance processes. It is concluded that the spatial and temporal trends in background European air mainly reflect the strength of primary diffusive emissions of these compounds and subsequently their ongoing declines. The direct evidence for this is similar rates of decline at all the sites; similar rates of decline for all congeners; no systematic change in the fractionation pattern since 1994. The latest results indicate a reduction in the rate of decline for PCBs (and hence in primary emissions).

Spatially explicit multimedia fate models for pollutants in Europe: state of the art and perspectives

A review by Hollander et al. (in preparation), discusses the relative potentials, advantages and shortcomings of spatial and non spatial models of chemical fate, highlighting that spatially explicit models may be needed for specific purposes. The present paper reviews the state of the art in spatially explicit chemical fate and transport modeling in Europe. We summarize the three main approaches currently adopted in spatially explicit modeling, namely (1) multiple box models, (2) numerical solutions of simultaneous advection-dispersion equations (ADE) in air, soil and water, and (3) the development of meta-models. As all three approaches experience limitations, we describe in further detail geographic information system (GIS)-based modeling as an alternative approach allowing a simple, yet spatially explicit description of chemical fate. We review the input data needed, and the options available for their retrieval at the European scale. We also discuss the importance of, and limitations in model evaluation. We observe that the high uncertainty in chemical emissions and physico-chemical behavior in the environment make realistic simulations difficult to obtain. Therefore we envisage a shift in model use from process simulation to hypothesis testing, in which explaining the discrepancies between observed and computed chemical concentrations in the environment takes importance over prediction per se. This shift may take advantage of using simple models in GIS with residual uses of complex models for detailed studies. It also calls for tighter joint interpretation of models and spatially distributed monitoring datasets, and more refined spatial representation of environmental drivers such as landscape and climate variables, and better emission estimates. In summary, we conclude that the problem is not "how to compute" (i.e. emphasis on numerical methods, spatial/temporal discretization, quantitative uncertainty and sensitivity analysis...) but "what to compute" (i.e. emphasis on spatial distribution of emissions, and the depiction of appropriate spatial patterns of environmental drivers).

Spatial and temporal pattern of pesticides in the global atmosphere

As part of the Global Atmospheric Passive Sampling (GAPS) study, XAD-resin based passive samplers are being deployed for consecutive one-year periods at numerous sites on all seven continents to determine annually averaged concentrations of persistent organic pollutants. Concentrations of banned organochlorine pesticides as well as a number of current-use pesticides in samples from the first four years, roughly coinciding with 2005, 2006, 2007 and 2008, show distinct spatial and temporal patterns. Whereas organochlorine pesticides such as alpha- and gamma-hexachlorocyclohexane, endosulfans, DDT and its metabolites, and chlordane-related compounds tend to be more prevalent in developing countries, especially in Asia, concentrations of current use pesticides such as trifluralin and chlorothalonil are often higher in Europe and North America. Based on 15 stations with four years of data, levels of hexachlorobenzene, hexachlorocyclohexanes and chlordanes decline in most world regions, which may reflect decreased usage in response to global restrictions. Levels of organochlorine pesticides in India, however, remain exceptionally high. Concentrations of alpha-endosulfan, chlorothalonil and trifluralin decrease in the European atmosphere during the sampling periods, indicating reduced usage. Consistently high alpha/gamma-HCH ratios in air samples from high Northern latitudes confirm that re-volatilization from the Arctic Ocean is a significant source of alpha-HCH. The highest levels of alpha-HCH, however, occur in conjunction with high gamma-HCH levels, suggesting that lindane use is now the major source of alpha-HCH to the global atmosphere. Although a wide variety of sampling site types aids in characterizing the entire global concentration variability of a pesticide, it also increases greatly the number of sites required for a robust regional differentiation.

Brominated flame retardants in the Arctic environment--trends and new candidates

Polybrominated diphenyl ethers (PBDEs) containing two to 10 bromines are ubiquitous in the Arctic, in both abiotic and biotic samples. Hexabromocyclododecane (HBCD) is also ubiquitous in the Arctic, with the gamma-HBCD isomer predominating in air, the alpha-HBCD isomer predominating in biota and similar concentrations of alpha-, beta- and gamma-HBCD found in marine sediments. Other brominated flame retardants (BFRs) found in some Arctic samples are polybrominated biphenyls (PBBs), tetrabromobisphenol A (TBBPA), 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE), hexabromobenzene (HxBBz), pentabromoethylbenzene (PBEB), pentabromotoluene (PBT), and 1,2-dibromo-4-(1,2-dibromoethyl)cyclohexane (TBECH). Temporal trends of tetra- to heptaBDEs and HBCD show increasing concentrations or a tendency to levelling off depending on the matrix (air, sediment, biota) and location, but no uniform picture for the Arctic emerges. BDE-209 concentrations are increasing in air. PBDEs and HBCD spatial trends in seabirds and marine mammals are similar to those seen previously for polychlorinated biphenyls (PCBs), with highest concentrations found in organisms from East Greenland and Svalbard. These trends indicate western Europe and eastern North America as important source regions of these compounds via long range atmospheric transport and ocean currents. Latitudinal trends showed lower concentrations and fluxes of PBDEs at higher latitudes. The tetra-hexaBDEs and alpha-HBCD biomagnify in Arctic food webs. Results for BDE-209 are more conflicting, showing either only low or no biomagnification potential. PBDE and HBCD concentrations are lower in terrestrial organisms and higher in marine top predators such as some killer whale populations in Alaska and glaucous gulls from the Barents Sea area. Higher concentrations are seen near populated areas indicating local sources. Findings of BTBPE, HxBBz, PBEB, PBT and TBECH in seabirds and/or marine mammals indicate that these compounds reach the Arctic, most probably by long range atmospheric transport and accumulate in higher trophic level organisms and that increasing use as PBDE replacements will lead to increasing concentrations.

Method optimization to measure polybrominated diphenyl ether (PBDE) concentrations in soils of Bratislava, Slovakia

We modified an analytical method to determine polybrominated diphenyl ethers (PBDEs) in urban soils of Bratislava (Slovakia). Gel permeation chromatography (GPC) introduced as a clean-up step for soil extracts substantially reduced matrix enhancements when PBDEs were measured with gas chromatography-negative chemical ionization-mass spectrometry (GC-NCI-MS). The resulting method proved to be accurate, precise, and showed low detection limits. The sum of 15 PBDE concentrations in surface horizons of Bratislava soils ranged from 87 to 627 pg g(-1). PBDE concentrations were mostly higher in surface than deeper horizons probably because of atmospheric deposition and lack of substantial vertical transport. Lower brominated PBDEs undergo more soil-atmosphere exchanges or are more scavenged and transferred with litter fall to the soil organic matter than higher brominated ones as suggested by the correlation between lower brominated PBDEs and soil organic C (C(org)) concentrations.

Urban-rural differences in breast cancer incidence in Egypt (1999-2006)

OBJECTIVE

To describe urban-rural differences in breast cancer incidence in Gharbiah, Egypt and to investigate if these differences could be explained by known risk factors of breast cancer.

METHODS

We used data from the population-based cancer registry of Gharbiah, Egypt to assess breast cancer incidence from 1999 through 2006. The Egyptian census provided data on district-specific population, age, and urban-rural classification. Incidence patterns of breast cancer by district and age-specific urban-rural differences were analyzed.

RESULTS

Overall, incidence rate of breast cancer was three to four times higher in urban areas than in rural areas (60.9/10(5)-year for urban areas versus 17.8/10(5)-year for rural areas; IRR=3.73, 95% CI=3.30, 4.22). Urban areas had consistently higher incidence of breast cancer across all age-groups for all years. Higher incidence of breast cancer was also seen in the more developed districts of Tanta and El-Mehalla.

CONCLUSIONS

Higher incidence of breast cancer in urban and more developed populations might be related to higher exposure to xenoestrogens, as well as other endocrine disruptors and genotoxic substances.

Investigation of source apportioning for alpha-HCH using enantioselective analysis

Enantiomeric analysis can be used as a complementary tool for source apportionment of chiral compounds, particularly for alpha-HCH. In this study we used archived samples from studies related to the distribution of POPs in air-water and air-soil-grass systems. Such approach is based on the behaviour of chiral compounds released into the atmosphere from a primary source, when they are expected to show racemic or close to racemic composition. Contrarily, when chiral compounds have been reemitted from secondary sources (e.g. water or soil), their enantiomeric signatures are frequently non-racemic and are similar to the signature of the secondary source. To show such evidence, extracts from passive air samples deployed throughout Europe were analyzed for the enantiomers of alpha-HCH. The proximity to a large water body showed a high impact on the enantiomeric signatures: Baltic air had enantiomeric fractions (EFs) <0.500, while Mediterranean air had predominantly EFs >0.500. Similarly, Atlantic air showed a latitude influence: above 50 degrees N most EFs <0.500, whereas at latitudes below 50 degrees N, EFs were >0.500. A similar trend was also observed for EFs of alpha-HCH measured in air samples from a latitudinal transect during an Atlantic cruise. This transect shows that samples from higher latitudes (above 40 degrees N) have EF <0.500, whereas in the more southern samples (African coast and Southern Atlantic), there is no clear trend for EFs. Inland air samples showed a large range in EF values, with racemic signatures for samples with the highest alpha-HCH concentrations and an increasing spread in the EFs for lower alpha-HCH concentrations. As expected, the EF values of alpha-HCH in air, soils and grass were also impacted by latitude. Correlations between EFs and geographic characteristics of the sampling locations, as well as alpha-HCH concentrations, alpha-/gamma-isomer ratios, or temperature suggest that enantioselective analysis can give additional information on the distribution and sources of alpha-HCH in the environment.

Spatial distribution of airborne polychlorinated biphenyls in Cleveland, Ohio and Chicago, Illinois

Passive samplers were deployed across Cleveland, OH and Chicago, IL to evaluate the spatial variability of airborne PCBs in urban areas. We measured SigmaPCB concentrations, the sum of 151 congeners or congener groups quantified using tandem mass spectrometry, spatial distributions, and congener profiles in two urban areas in the Great Lakes region. Mean SigmaPCB concentrations were significantly different between Cleveland (1.73 +/- 1.16 ng m(-3)) and Chicago (1.13 +/- 0.58 ng m(-3)) during the August 2008 sampling period. Mean congener profiles were compared with commercial Aroclor mixtures and found to be similar to Aroclor 1242 in Cleveland and similar to a mixture of 1242 and 1254 in Chicago. We observed large spatial variation in concentrations and weak or no significant autocorrelation between sites in both cities. "Hot spots" of high SigmaPCB concentrations were identified in both urban areas and the congener profiles at these locations were most strongly correlated to that of PCB Aroclor mixtures. Congener profiles showed important differences including the enrichment of dioxin-like congeners in Chicago.

Passive air sampling of organochlorine pesticides, polychlorinated biphenyls, and polybrominated diphenyl ethers across the tibetan plateau

So far there are limited data on persistent organic pollutants (POPs) in the atmosphere of the Tibetan Plateau. XAD 2-resin based passive air samplers were therefore deployed for 1 year (between July 2007-June 2008) at 16 locations across the Tibetan Plateau. Based on previously reported sampling rates (R) derived in the north and south America, and their correlations with atmospheric temperature and pressure, R values in the present study were in the range of 2.2-3.3 m(3) d(-1) (average = 2.7 +/- 0.3). Derived air concentrations (pg/m(3)) ranged as follows: DDTs, 5-75; HCHs, 0.1-36; alpha-endosulfan, 0.1-10; HCB, 2.8-80; sum of 15 PCBs, 1.8-8.2; and sum of 9 PBDEs, 0.1-8.3. The highest DDTs occurred at Qamdo, where the sampling site is near to farm land, indicating the spatial distribution of DDTs across the plateau may be influenced by scattered local usage of DDT. Higher levels of HCHs were observed at sites with high elevation (>4000 m) and close to the China-India border, indicating possible long-range atmospheric transport. The highest levels of HCB, PCBs, and PBDEs were found at a site impacted by forest fire during the sampling campaign.

Spatial distribution of polybrominated diphenyl ethers and hexabromocyclododecanes in sediments from coastal waters of Korea

Polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecanes (HBCDs) were determined in surface sediments collected from 24 coastal locations in Korea. The concentrations of summation operatorPBDEs (defined as the sum of all targeted PBDE congeners except for BDE-209) and BDE-209 ranged from 0.05 to 32 ng g(-1) dry wt. and from 0.40 to 98 ng g(-1) dry wt., respectively. The PBDE congener compositions were dominated by BDE-209, which is in accordance with the consumption of decaBDE mixture in Korea. HBCD concentrations ranged from 0.39 to 59 ng g(-1) dry wt. Concentrations of PBDEs and HBCDs were found to be higher near locations with industrial complexes and harbors, associating these compounds to urbanization and industrialization. Significant positive correlations between PBDE and HBCD concentrations and organic carbon content in sediments imply the role played by organic matter in the contaminant transport and trapping in the aquatic environment.

Distribution pattern of PCBs, HCB and PeCB using passive air and soil sampling in Estonia

BACKGROUND, AIM, AND SCOPE

Passive air sampling survey of the Central and Eastern Europe was initiated in 2006. This paper presents data on toxic organic compounds such as polychlorinated biphenyls (PCB 28, 52, 101, 118, 153, 138, and 180), hexachlorobenzene (HCB), pentachlorobenzene (PeCB), hexachlorocyclohexane compounds (alpha-HCH, beta-HCH,gamma-HCH, delta-HCH), and dichloro-diphenyl-trichloroethane (DDT) compounds (p,p'DDE, p,p'DDD, p,p'DDT, o,p'DDE, o,p'DDD, and o,p'DDT) determined in ambient air and soil samples collected at Estonian monitoring stations.

MATERIALS AND METHODS

Ambient air and soil samples were collected in five sites in northern Estonia. Passive air samplers were deployed four times over 4-week periods covering the period April-August 2006. Samples were analyzed using gas chromatography-electron capture detector (HP 5890) supplied with a Quadrex fused silica column 5% Ph for organochlorine pesticides (OCPs). Local ground-boundary wind field was modeled for each monitoring station and sampling period on the basis of observed wind data from the nearest meteorological station with a high quality of time series and compared with upper air (at 850- and 500-hPa level) data from Tallinn-Harku aerological station.

RESULTS

Median levels of PCB at Estonian stations varied between 3 and 9 ng/filter, although the maximum in Kohtla-Järve reached as high as 28 ng/filter. Sampling rates about 3.5 m(3)/day were determined by empirical measurements, making approximately 100 m(3) for a 28-day sampling cycle. In general, OCP levels in soil were at the limit of detection, except Tallinn site and Muuga Port affected mainly by local sources. However, the atmospheric PCB concentrations are in agreement with the soil analyses where highest PCB levels were found in the soil sample for Tallinn (12.0 ng/g dry weight). For HCB, the atmospheric distribution was quite uniform, with the background levels sometimes higher than the urban ones. HCB and PeCB concentrations were very low in May and June when meridional airflow from the southern sector dominated, and concentrations were slightly higher in July and August, most probably due to revolatilization of adsorbed HCB (with PeCB impurities) from former industrial applications during the summer month and possibly enhanced by forest fires in Russia. Also, the highest summary HCH and DDT levels (63.5 and 2.5 ng/filter, respectively) in Estonian monitoring stations were determined at the end of July and beginning of August when the ground-boundary wind direction was from NE with relatively high speed (4-7 m/s). The highest DDT levels in ambient air (3.5 ng/filter) were determined in the spring samples. For DDT and HCH, long-range atmospheric transport clearly dominates persistent OCP, atmospheric input to Estonia as well as for the Scandinavian countries. The DDE/DDT ratio was >1, indicating no fresh input.

DISCUSSION

The passive air sampling demonstrates uniform distribution of OCPs. In the regional context, there is no indication of increased levels of concentrations of OCPs in the industrial Northeast Estonia where the oil shale processing causes certain pollution impacts. Though the passive sampling does not apply for monitoring of short-term fluxes, the method is capable of reflecting background levels in long-term prospective for potential effect on human health due to long-term exposition of OCPs.

CONCLUSIONS

PCB and its congeners, HCB, PeCB, HCH, and DDT were very low in Estonia. None of the persistent organochlorine pesticides have ever been produced in Estonia, and as of today, all old OCP stocks in the country have been destroyed. Highest concentrations could be expected in March and April when southwestern airflow is still strong and dominant, but air humidity is lower and deposition takes place far from the place of origin of OCPs. In summer, the share of locally formed organic compounds increases and deposition depends strongly on weather conditions. In some cases in Tallinn and Muuga where local anthropogenic impact occurs, HCB and PeCB stem from revolatilization of industrial application.

RECOMMENDATIONS AND PERSPECTIVES

The passive air sampling could be employed more widely to explore long-term human exposure to OCP deposition and assess potential health risks. The survey based on passive air sampling could be extended from Central and Eastern Europe to other European regions to get methodically adjusted cross-European data coverage. Based on the results of the survey, the Lahemaa reference station is a feasible option to represent background monitoring of persistent organic pollutants.

The use of blue tit eggs as a biomonitoring tool for organohalogenated pollutants in the European environment

In the present study, large scale geographical variation in the occurrence of organohalogenated pollutants (OHPs) was investigated throughout Europe using eggs of a terrestrial resident passerine species, the blue tit (Cyanistes caeruleus). Blue tit eggs from 10 sampling locations, involving suburban, rural and remote areas, in 7 European countries were collected and analysed. Sum polychlorinated biphenyl (PCB) levels ranged from 150ng/g lipid weight (lw) to 2003ng/g lw. Sum polybrominated diphenyl ethers (PBDEs) ranged from 3.95ng/g lw to 114ng/g lw. As expected, PCB and PBDE concentrations were significantly higher in the sampled suburban locations compared to the rural and remote locations. Sum organochlorine pesticides (OCPs) ranged from 122ng/g lw to 775ng/g lw. OCP concentrations were, against the expectations, found to be lower in the rural sampling locations compared to the other locations. Contamination profiles of PCBs, PBDEs and OCPs differed also among the sampling locations, which may be due to local contamination sources. Finally, we compared the results of this study with previously reported OHP concentrations in the eggs of a closely related species, the great tit (Parus major), from the same sampling locations in Europe. We found no differences in concentrations between the species. In addition, we found a significant, positive correlation between the sum PCB concentrations in blue tit eggs and great tit eggs, suggesting similar exposure pathways, mechanisms of accumulation and maternal transfer of PCBs. In conclusion, our results suggest the usefulness of eggs from passerine birds as a biomonitoring tool for OHPs on a large geographical scale.

The potential effect of differential ambient and deployment chamber temperatures on PRC derived sampling rates with polyurethane foam (PUF) passive air samplers

Performance reference compound (PRC) derived sampling rates were determined for polyurethane foam (PUF) passive air samplers in both sub-tropical and temperate locations across Australia. These estimates were on average a factor of 2.7 times higher in summer than winter. The known effects of wind speed and temperature on mass transfer coefficients could not account for this observation. Sampling rates are often derived using ambient temperatures, not the actual temperatures within deployment chambers. If deployment chamber temperatures are in fact higher than ambient temperatures, estimated sampler-air partition coefficients would be greater than actual partition coefficients resulting in an overestimation of PRC derived sampling rates. Sampling rates determined under measured ambient temperatures and estimated deployment chamber temperatures in summer ranged from 7.1 to 10 m(3) day(-1) and 2.2-6.8 m(3) day(-1) respectively. These results suggest that potential differences between ambient and deployment chamber temperatures should be considered when deriving PRC-based sampling rates.

Hexachlorobenzene sources, levels and human exposure in the environment of China

This article summarizes the published scientific data on sources, levels and human exposure of hexachlorobenzene (HCB) in China. Potential sources of unintended HCB emission were assessed by production information, emission factors and environmental policies. HCB was observed in various environmental compartments in China. HCB levels increased from South China to North China in most of environmental compartments (air, soil and mussel). Some hotspots were identified near the factories producing and using HCB. In terms of spatial distribution, HCB concentrations in air and shellfish showed much variation, which indicated some primary emission sources in China. HCB levels in air and human milk in China were relatively higher than those in other countries, but HCB levels in other compartments were similar to those in Europe and other countries in Eastern Asia. In the limited studies on temporal trends of HCB levels in China, HCB concentrations in air, sediment, fish and human milk did not show a consistent downward trend. Although HCB levels in food and human milk does not pose a health risk in China at present, long-term exposure to HCB should not be overlooked.

How do long-term development and periodical changes of river-floodplain systems affect the fate of contaminants? Results from European rivers

In many densely populated areas, riverine floodplains have been strongly impacted and degraded by river channelization and flood protection dikes. Floodplains act as buffers for flood water and as filters for nutrients and pollutants carried with river water and sediment from upstream source areas. Based on results of the EU-funded "AquaTerra" project (2004-2009), we analyze changes in the dynamics of European river-floodplain systems over different temporal scales and assess their effects on contaminant behaviour and ecosystem functioning. We find that human-induced changes in the hydrologic regime of rivers have direct and severe consequences on nutrient cycling and contaminant retention in adjacent floodplains. We point out the complex interactions of contaminants with nutrient availability and other physico-chemical characteristics (pH, organic matter) in determining ecotoxicity and habitat quality, and draw conclusions for improved floodplain management.

Occurrence and diurnal variation of polychlorinated biphenyls and polybrominated diphenyl ethers in the background atmosphere of Eastern Mediterranean

During a two-week intensive field campaign conducted at a background location of the Eastern Mediterranean, consecutive 10-h air samples were collected under intense photochemical conditions and analyzed for polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs). The average gas-phase concentration of total PCBs and PBDEs was 73+/-29 and 3.9+/-2.1 pg m(-3), respectively. The study of Clausius-Clapeyron plots and air mass back-trajectories assigned the origin of air masses as the factor largely controlling the variation of PCB and PBDE air concentrations in the study area. Using principal component analysis, discrete differences in PCBs homologue profiles were revealed between day and night samples and attributed to the daytime reaction with hydroxyl radicals. In contrast, PBDE homologue profiles did not show any characteristic day-to-night shifts that could be attributed to hydroxyl radical reaction or photolysis.

Lindane residues in cultivated cucumber and in the most consumed fish in Caspian Sea (Iran)

In this study, the concentrations of lindane residues (organochlorine pesticides) were analyzed in samples of cultivated cucumbers ( Cucumis sativus L.) and four species of most consumed fish (Sefid, Koli, Kilca and Kafal fish). Samples of cucumber were collected from five sites in Sari city (north, south, east, west and central areas) and samples of fish were caught using electric fishing from four major fishing centers (Chalous and Babolsar cities, Khazar Abad and Miankaleh regions) in Mazandaran province of Iran. Quantitative determination of the lindane content was performed by gas chromatography electron-capture detection (GC-ECD). The results showed that the concentration of lindane in cucumber samples and in the dorsal muscle of the selected fish were less than the Food and Agriculture Organization/World Health Organization (FAO/WHO) recommended intake.

Polyfluorinated compounds in the atmosphere of the Atlantic and Southern Oceans: evidence for a global distribution

High volume air samples taken onboard several research vessels in the Atlantic Ocean, the Southern Ocean, and the Baltic Sea as well as at one land-based site close to Hamburg, Germany, in 2007 and 2008 were analyzed for per- and polyfluorinated organic compounds (PFCs). A set of neutral, volatile PFCs such as fluorotelomer alcohols (FTOH) or perfluoroalkyl sulfonamides and ionic nonvolatile PFCs like perfluorinated carboxylates (PFCA) and sulfonates (PFSA) were collected on PUF/XAD-2/PUF cartridges and glass fiber filters and determined using GC-MS and HPLC-MS/MS. PFCs were detected in all air samples, even in Antarctic regions, and occurred predominantly in the gas phase. Total gas-phase concentrations of ship-based samples ranged from 4.5 pg m(-3) in the Southern Ocean to 335 pg m(-3) in European source regions. Concentrations of 8:2 FTOH, the analyte that was usually observed in highest concentrations, were between 1.8 and 130 pg m(-3). PFC concentrations decreased from continental regions toward marine regions and from Central Europe toward the Arctic and Antarctica. Southern hemispheric concentrations of individual PFCs were significantly lower than those of the northern hemisphere. On the basis of this data set, marine background PFC concentrations and atmospheric residence times were calculated. This study gives further evidence that volatile PFCs undergo atmospheric long-range transportto remote regions and may contribute to their contamination with persistent PFCA and PFSA.

Important role of reaction field in photodegradation of deca-bromodiphenyl ether: theoretical and experimental investigations of solvent effects

Photolysis of deca-bromodiphenyl ether (BDE-209) was investigated in tetrahydrofuran, dichloromethane, isopropanol, acetone, ethanol, methanol, acetonitrile and dimethylsulfoxide. Noticeable differences of the photolytic rates and quantum yields were found in the diverse solvents. Different to the previous deductions, hydrogen donating efficiency and electron donating efficiency of solvents were not the decisive factors for the photolytic rate in this study, which was proved by the fast photolysis of BDE-209 in CCl(4), a solvent without hydrogen and difficult to donate electrons. Besides hydrogen addition process, intermolecular polymerization might occur during the photolysis. Density functional theory (DFT) calculation was performed to understand the molecular properties of BDE-209 in different solvents. The lowest singlet vertical excitation energy (E(ex)) and the average formal charge on Br (q(Br)(+)) of BDE-209, reflecting the difficulty for the excitation of BDE-209 and for the departing of Br atom, respectively, were changed by the reaction fields formed by the different solvents. E(ex) and q(Br)(+) linearly correlated with the photolytic activity (logk). This study is helpful to better understand the photolytic behavior of BDE-209 in different media.

Concentrations and emissions of polybrominated diphenyl ethers from U.S. houses and garages

Concentrations of polybrominated diphenyl ethers (PBDEs) and other brominated flame retardants (BFRs) have been rapidly increasing in fish, birds, sediments, indoor environments, and humans, but emission sources and exposure pathways of these pollutants remain poorly understood. The many BFR-containing materials in buildings constitute a large reservoir of these compounds, and in-use releases from this reservoir may be a significant environmental source. To estimate in-use releases from building materials and contents in residences, we monitored 12 houses and garages in two seasons and combined measurements of BFRs in air and settled dust, air exchange rates, and other information in an approach that utilized the building as a "natural" test chamber. Results were scaled to provide a first estimate of aggregate emission rates from U.S. houses. PBDE releases total about 4 microg h(-1) per house or 20 ng m(-2) h(-1), and U.S. houses and garages collectively release about 4100 kg y(-1). Most of these releases are settled floor dust, but about 20% are released directly to the ambient environment via airborne vapor and particulate matter. These screening-level estimates are subject to considerable uncertainty, but they have an advantage in that they reflect real-world conditions based on mass balance calculations.

Passive air sampling for polychlorinated biphenyls in the Philadelphia metropolitan area

Passive air samplers were deployed at 32 sites across the Philadelphia metropolitan area to investigate the types and locations of atmospheric polychlorinated biphenyl (PCB) sources in a typical U.S. city. PCB levels varied over a factor of approximately 30 and displayed strong spatial gradients. Two regions of high PCB levels were observed, one in the center of Philadelphia and another on the city's south side. These two maxima are thought to represent urban vs. industrial sources. A Gaussian diffusion model was found to adequately describe the spatial gradients for the primary (center city) concentration maximum. Higher molecular weight PCBs were more prevalent at the more urban locations, in agreement with other urban gradient studies and suggesting that re-emission (i.e., secondary sources) of PCBs are important Positive matrix factorization analysis resolved two factors that are interpreted to represent light Aroclors and a heavier industrial source concentrated atthe secondary maximum on the city's south side. The results generally corroborate an earlier study in which data from the New Jersey Atmospheric Deposition Network site in Camden, NJ, was used to investigate source types and locations. Additionally, the non-Aroclor congener PCB 11 (3,3'-dichlorobiphenyl) was detected in all samples.

Seasonal patterns and current sources of DDTs, chlordanes, hexachlorobenzene, and endosulfan in the atmosphere of 37 Chinese cities

China has a history of large scale production and application of organochlorine pesticides (OCPs) although, data on their nationwide distribution and seasonal variations in the atmosphere is still sparse. Passive air samplers (PAS) were therefore utilized to obtain seasonal data from 37 Chinese cities and three background sites in 2005. Concentrations and spatial and seasonal distribution of dichlorodiphenyltrichloroethanes (DDTs), chlordanes (CHLs), hexachlorobenzene (HCB), and endosulfans (Endo) are presented in this paper, and their potential sources are discussed based on the dataset. It is estimated that ca. 95% of DDTs present in the atmosphere of Chinese cities was still from technical DDT, while only ca. approximately 5% was "dicofol-type of DDT". DDT application for public health control and DDT activated antifouling paint for fishing ships may be the two most important current sources of technical DDT. The DDT concentrations in several Chinese cities seem to match well with the reported DDT concentrations in human breast milk. A low TC/CC ratio was observed across China in the winter to spring, which may provide a fingerprint of Chinese chlordane emission. It was suggested that "weathered" chlordane emitted from urban construction foundations in winter may give the distinctively low TC/CC ratio. The data showed that China is an important global source for HCB. Higher HCB concentrations were observed in winter and spring, and in colder cities, highlighting an important contribution from combustion sources. Samples with higher endosulfan concentrations occurred in the cotton production areas, indicating its major use in killing cotton pests.

Levels and vertical distributions of PCBs, PBDEs, and OCPs in the atmospheric boundary layer: observation from the Beijing 325-m meteorological tower

Polyurethane foam disk passive air sampling was carried out to investigate the levels, vertical distributions, and potential sources of polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and organochlorine pesticides (OCPs) in the atmospheric boundary layer of an urban site in Asia. Sampling was performed at nine heights (15, 47, 80, 120, 160, 200, 240, 280, 320 m) of the 325-m meteorological tower in Beijing, China over three 2-month periods between December 2006 and August 2007. This is the first study to report vertical variations of PBDEs in the ABL and one of only a few studies to investigate vertical distributions of persistent organic pollutants. The levels of sigma19PCBs and sigma8PBDEs were relatively low, ranging from 22 to 65 and from 2.3 to 18 pg m(-3), respectively. Air concentrations of gamma-HCH were high, with values in the range of 39-103 pg m(-3) in winter, 100-180 pg m(-3) in spring, and 115-242 pg m(-3) in summer, respectively. alpha-HCH concentrations ranged from 20 to 86 pg m(-3), p,p'-DDT between 7.3 and 78 pg m(-3), and HCB between 15 and 160 pg m(-3). The seasonal variations of PCBs, PBDEs, and OCPs may reflect different sources for these chemicals, such as those related with regional use (gamma-HCH), volatilization/re-emission (PBDEs, PCBs, alpha-HCH), and pesticide impurities (HCB). Although the performance reference compounds (PRCs) were spiked before deployment, the sampling rates showed strong dependency on wind speeds, resulting in large variations in uptake rates in the ABL, ranging from approximately 7.0 m3 day(-1) at ground level to 11 m3 day(-1) at 320 m. Levels of PCBs, PBDEs, and OCPs decreased with increasing ABL height indicating the potential of Beijing as the local sources.

Brominated flame retardants and organochlorines in the European environment using great tit eggs as a biomonitoring tool

Large-scale studies are essential to assess the emission patterns and spatial distribution of organohalogenated pollutants (OHPs) in the environment. Bird eggs have several advantages compared to other environmental media which have previously been used to map the distribution of OHPs. In this study, large-scale geographical variation in the occurrence of OHPs, such as polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and organochlorine pesticides (OCPs), was investigated throughout Europe using eggs of a terrestrial residential passerine species, the great tit (Parus major). Great tit eggs from 22 sampling sites, involving urban, rural and remote areas, in 14 European countries were collected and analysed (5-8 eggs per sampling site). The environmentally most important congeners/compounds of the analysed pollutants were detectable in all sampling locations. For PCBs, PBDEs and OCPs, no clear geographical contamination pattern was found. Sum PCB levels ranged from 143 ng/g lipid weight (lw) to 3660 ng/g lw. As expected, PCB concentrations were significantly higher in the sampled urban compared to the remote locations. However, the urban locations did not show significantly higher concentrations compared to the rural locations. Sum PBDEs ranged from 4.0 ng/g lw to 136 ng/g lw. PBDEs were significantly higher in the urbanized sampling locations compared to the other locations. The significant, positive correlation between PCB and PBDE concentrations suggests similar spatial exposure and/or mechanisms of accumulation. Significantly higher levels of OCPs (sum OCPs ranging from 191 ng/g lw to 7830 ng/g lw) were detected in rural sampling locations. Contamination profiles of PCBs, PBDEs and OCPs differed also among the sampling locations, which may be due to local usage and contamination sources. The higher variance among sampling locations for the PCBs and OCPs, suggests that local contamination sources are more important for the PCBs and OCPs compared to the PBDEs. To our knowledge, this is the first study in which bird eggs were used as a monitoring tool for OHPs on such a large geographical scale.

Concentrations in bird feathers reflect regional contamination with organic pollutants

Feathers have recently been shown to be potentially useful non-destructive biomonitoring tools for organic pollutants. However, the suitability of feathers to monitor regional variations in contamination has not been investigated until now. Here concentrations of organic pollutants were compared in feathers of common magpies (Pica pica) between urban and rural areas in Flanders, Belgium. The results showed that concentrations of p,p'-dichlorodiphenyldichloroethylene (DDE) were significantly higher in the rural areas (rural: 12-140 ng/g feather, urban: 1.1-7.2 ng/g feather), while polychlorinated biphenyls (PCBs) were significantly more available in an urban environment (sum PCBs--rural: 2.9-22 ng/g feather, urban: 41-240 ng/g feather). This pattern agrees with previous studies using other tissues than feathers as a biomonitoring tool. In addition, differences in PCBs and PBDEs profiles were found with lower halogenated congeners being more prominent in the urban areas in comparison to the rural areas. In summary, feathers seem to reflect regional variations in contamination, which strengthens their usefulness as a non-destructive biomonitor for organic pollutants.

Seasonally resolved concentrations of persistent organic pollutants in the global atmosphere from the first year of the GAPS study

Concentrations of persistent organic pollutants (POPs) in air are reported from the first full year of the Global Atmospheric Passive Sampling (GAPS) Network. Passive air samplers composed of polyurethane foam disks (PUF-disk samplers) were deployed over four consecutive three-month periods in 2005 to measure seasonal concentrations of POPs at a variety of site types on a global scale, with an emphasis on background/remote locations. Samples for the last three quarters are reported here for the first time. Annual geometric mean (GM) concentrations in air (pg x m(-3)) were highest for endosulfan, a currently used pesticide (GM = 82), and polychlorinated biphenyls (PCBs) (GM = 26). Other chemicals regularly detected included alpha- and gamma-hexachlorocyclohexane (HCH), chlordanes, heptachlor, heptachlor epoxide, dieldrin, p,p'-DDE and polybrominated diphenyl ethers (PBDEs). With the exception of lower concentrations during the first quarter, no seasonal patterns were observed on a global basis. In contrast, some distinct seasonal patterns were observed on a site-specific basis. For instance, endosulfans exhibited strong seasonality with highest concentrations during the summer periods, especially at or near agricultural sites. The latitudinal distribution of target chemicals reflected the estimated spatial variability of global emissions, with highest concentrations observed in the midlatitudes of the northern hemisphere. In the case of PCBs, the GAPS data reflected and were well correlated with global emission estimates, with highest concentrations in developed and industrialized regions. Data provided through the GAPS Network establish global baseline values, and continuation of the time series will contribute to the effectiveness evaluation of global treaties on POPs (e.g., Stockholm Convention). Globally resolved data will also foster the development and validation of global transport models for POPs, and the investigation of seasonal and interannual trends in concentrations of POPs in the global atmosphere.

Calculation of passive sampling rates from both native PCBs and depuration compounds in indoor and outdoor environments

Passive sampling has become a practical way of sampling persistent organic pollutants over large spatial and remote areas; however, its ease in use is also coupled with some uncertainty in calculating air concentrations from accumulated mass. Here we report a comparison study of polyurethane-foam-based passive samplers (PUF-PAS) for quantitatively determining the sampling rates of polychlorinated biphenyls (PCBs) from air. We measured both uptake of native PCBs and loss of depuration compounds and determined the sampling rates (R-values) for multiple samplers harvested at three different time periods. The uptake of native PCBs in the linear phase was similar to the loss of depuration compounds for indoor air and behaved as predicted. A single R-value of 2.6m(3)d(-1) was calculated from the mean of 12 samplers deployed indoors from three harvest dates with a range of 2.0-3.4m(3)d(-1) for both uptake of native PCBs and loss of depuration compounds. Loss of depuration compounds in outdoor air also followed the predicted linear behavior with a range of calculated R-value of 4.4-8.4m(3)d(-1). Uptake of native PCBs behavior was extremely variable, probably due to changes in ambient air concentrations and resulted in R-values of 1.6-11.5m(3)d(-1) with greater variation seen in higher chlorinated homolog groups.

Passive air sampling of organochlorine pesticides in Mexico

The spatial and temporal variation of organochlorine pesticides (OCs) in air across Mexico was investigated by deploying passive samplers at eleven stations across the country during 2005-2006. Integrated samples were taken over three-month periods and quantified for DDT compounds, endosulfans, toxaphenes, components of technical chlordane, hexachlorocyclohexanes (HCHs), and dieldrin. Enantiomers of chiral chlordanes and o,p'-DDT were determined on chiral stationary phase columns as an indicator of source and age. Results are discussed in combination with pumped air samples taken at four other stations in southern Mexico during 2002-2004. DDT and its metabolites, endosulfan and toxaphene were the most abundant OCs detected in all sampling sites. Atmospheric concentrations of SigmaDDT (p,p'-DDT + o,p'-DDT + p,p'-DDE + o,p'-DDE + p,p'-DDD + o,p'-DDD) ranged from 15 to 2360 pg m(-3) with the highest concentrations found in southern Mexico and the lowest found in northern and central Mexico. A fresher DDT residue was observed at sites with greater DDT use and in the southern part of the country, as shown from the higher FDDTe = p,p'-DDT/(p,p'-DDT + p,p'-DDE) and nearly racemic o,p'-DDT. This agrees with the former heavy use of DDT in the endemic malarious area of the country. A local hotspot of endosulfan was identified at an agricultural area in Mazatlan, Sinaloa, with a annual mean concentration of SigmaENDO (endosulfans I + II + endosulfan sulfate) = 26,800 pg m(-3). At this site, higher concentrations of SigmaENDO were recorded during the winter (November to February) and spring (February to May) periods. From back trajectory analysis, this coincides with a shift in the air mass coming from the Pacific Ocean (May to November) to the inland agricultural area (November to May). The elevated SigmaENDO observed is likely due to the local agricultural usage. HCHs, chlordanes, transnonachlors, and dieldrin were more evenly distributed across the country likely due to them being aged residues and more diffuse in the environment. In contrast, hotspots of endosulfans, DDTs, and toxaphenes were observed as they were heavily used in localized agricultural or malarious regions of Mexico.

Modeling the environmental fate of polybrominated diphenyl ethers (PBDEs): the importance of photolysis for the formation of lighter PBDEs

A global multimedia model is used to calculate the fate of polybrominated diphenyl ethers (PBDEs) in the environment. Special emphasis is given to the importance of direct photolysis, which has been shown to be an important degradation mechanism for highly brominated PBDEs and is believed to result in the formation of lower-brominated PBDEs. We show that the inclusion of direct photolysis decreases the overall persistence and long-range transport potential of most PBDEs, in particular the heavier ones. We develop a PBDE emission inventory and calculate environmental concentrations of different PBDEs. Differences between predicted concentrations and field data are assessed and possible reasons for these differences discussed. The formation of lighter PBDEs by debromination of deca-BDE is compared to direct emissions of lighter PBDE homologues. The model estimates that about 13% of the penta-BDE and about 2% of the tetra-BDE homologue found in the environment arise from the degradation of deca-BDE. Uncertainties of the model estimates are quantified and their implications for the findings of our study discussed.

Field calibration of polyurethane foam (PUF) disk passive air samplers for PCBs and OC pesticides

Different passive air sampler (PAS) strategies have been developed for sampling in remote areas and for cost-effective simultaneous spatial mapping of POPs (persistent organic pollutants) over differing geographical scales. The polyurethane foam (PUF) disk-based PAS is probably the most widely used. In a PUF-based PAS, the PUF disk is generally mounted inside two stainless steel bowls to buffer the air flow to the disk and to shield it from precipitation and light. The field study described in this manuscript was conducted to: compare performance of 3 different designs of sampler; to further calibrate the sampler against the conventional active sampler; to derive more information on field-based uptake rates and equilibrium times of the samplers. Samplers were also deployed at different locations across the field site, and at different heights up a meteorological tower, to investigate the possible influence of sampler location. Samplers deployed <5m above ground, and not directly sheltered from the wind gave similar uptake rates. Small differences in dimensions between the 3 designs of passive sampler chamber had no discernable effect on accumulation rates, allowing comparison with previously published data.

Passive atmospheric sampling of organochlorine pesticides, polychlorinated biphenyls, and polybrominated diphenyl ethers in urban, rural, and wetland sites along the coastal length of India

India is of prime interest due to the large past and ongoing use of pesticidal persistent organic pollutants (POPs). Rapid dissipation of POPs to the atmosphere in the tropical climate of India infers an atmospheric outflow of these chemicals. Yet data on POPs in the atmosphere of India are sparse. Passive air samplers consisting of polyurethane foam disks were therefore deployed concurrently at 18 locations and exposed for 6 weeks from July 30, 2006, to September 26, 2006, along the coastal length of India to screen for POPs in the atmosphere. The sampling sites were selected to form categories of urban, rural, and background (mangrove/wetlands) locations. Derived air concentrations (pg/m3) ranged as fellows: the sum of 28 PCB congeners, 120-1080; DDTs, 16-2950; HCHs, 66-5400; chlordanes, 9-921; endosulfans, 0.45-1120; and the sum of 9 PBDE congeners, 1-181. The highest levels of all the detected POPs (except endosulfan) were observed at the urban sites, indicating the dominant areas of usage and emissions. An urban-rural composition fractionation of PCBs indicates their atmospheric movement. The gamma-HCH levels were more than double those of alpha-HCH, indicating the sporadic use of lindane. DDT concentrations were elevated, at levels comparable to China, but with much higher percentages of p,p'-DDE, reflecting a more 'weathered' feature. Although no dicofol use was recorded in India, the o,p'-/p,p'-DDT ratios were observed to be even higher than in China. Chlordanes showed high trans-/cis-chlordane (TC/CC) ratios, indicative of the current use of technical chlordane and a contribution from heptachlor usage.

Spatial patterns of polybrominated diphenyl ethers (PBDEs) in mosses, herbivores and a carnivore from the Norwegian terrestrial biota

The widespread occurrence of polybrominated diphenyl ethers (PBDEs) in the environment has attracted considerable attention, leading to concerns about the extent and magnitude of wildlife and human exposure. In this work, we focus on the occurrence and fate of PBDEs in a Norwegian air-plant-herbivore-carnivore system. Specifically, we have analysed for PBDEs in moss, livers from various terrestrial herbivores (moose, grouse, and European roe deer) and, for the first time, livers from the top predator lynx. The samples were collected from different sites and time periods (1990-2004) to identify possible spatial and temporal trends in contaminant levels and patterns. The general finding was that PBDEs were found in all (biotic) samples, although at lower concentrations than previously observed in mammals from the marine environment. The PBDE levels in the herbivores ranged from less than 0.5 ng/g lipid weight to 9.4 ng/g lipid weight as the highest. The median PBDE concentration in lynx was approximately one order of magnitude higher than in the herbivores. In the lynx samples there was a predominance of BDE-153 whereas BDE-47 and 99 dominated in the herbivores. This probably reflects different bioaccumulation properties or metabolic transformation processes of the BDE-congeners, and food choice. Levels of PBDEs in both moss and herbivores showed a general decline towards the northern parts of Norway. No clear temporal trends were observed. The PBDE levels observed in this study were low and are probably of limited toxicological significance.

Assessment of the spatial distribution of coplanar PCBs, PCNs, and PBDEs in a multi-industry region of South Korea using passive air samplers

Coplanar polychlorinated biphenyls (PCBs), polychlorinated naphthalenes (PCNs), and polybrominated diphenyl ethers (PBDEs) were sampled using polyurethane foam (PUF) disk passive air samplers (PAS) at 19 sites in a heavily industrialized region of South Korea for 6 months (January-July 2006). The levels and spatial distribution of these three chemical groups were investigated to identify potential sources and transport in the study area, which can be divided into five regions: a steel-manufacturing complex, a residential area near the steel complex, a rural area, a semi-industrial area, and a petrochemical-manufacturing complex. Air concentrations (pg x m(-3)) were estimated using an average sampling rate of 3.0 m3 x day(-1) and ranged as follows: coplanar PCBs (0.8-16), PCNs (1.7-35), and PBDEs (3.8-24). The levels of coplanar PCBs and PBDEs were found to be the highest in the steel complex, followed by the petrochemical complex and the semi-industrial area. In addition, a high level of PCNs was measured near a petrochemical-processing plant. However, the residential area near the steel complex and the rural area showed relatively low concentrations of these chemicals, suggesting that the steel and petrochemical industries are probably important sources in the study area, but these potential sources do not strongly influence the surrounding areas.

Field testing passive air samplers for current use pesticides in a tropical environment

Air was sampled for one year in the central valley of Costa Rica using an active high-volume sampler as well as passive samplers (PAS) based on polyurethane foam (PUF) disks and XAD-resin filled mesh cylinders. Extracts were analyzed for pesticides that are either banned or currently used in Costa Rican agriculture. Sampling rates for PUF-based passive air samplers, determined from the loss of depuration compounds spiked on the disks prior to deployment averaged 5.9 +/- 0.9 m3 x d(-1) and were higher during the windier dry season than during the rainy season. Sampling rates for the XAD-based passive sampler were determined from the slopes of linear relationships that were observed between the amount of pesticide sequestered in the resin and the length of deployment, which varied from 4 months to 1 year. Those sampling rates increased with decreasing molecular size of a pesticide, and their average of 2.1 +/- 1.5 m3 x d(-1) is higher than rates previously reported for temperate and polar sampling sites. Even though the trends of the sampling rate with molecular size and temperature are consistent with the hypothesis that molecular diffusion controls uptake in passive samplers, the trends are much more pronounced than a direct proportionality between sampling rate and molecular diffusivity would suggest. Air concentrations derived by the three sampling methods are within a factor of 2 of each other, suggesting that properly calibrated PAS can be effective tools for monitoring levels of pesticides in the tropical atmosphere. In particular, HiVol samplers, PUF-disk samplers, and XAD-based passive samplers are suitable for obtaining information on air concentration variability on the time scale of days, seasons and years, respectively. This study represents the first calibration study for the uptake of current use pesticides by passive air samplers.

Analysis of polychlorinated biphenyls in concurrently sampled Chinese air and surface soil

Polychlorinated biphenyl (PCB) concentrations were measured in a concurrent air and surface soil sampling program across China. Passive air samples were collected for approximately 3 months from mid-July to mid-October, 2005 using polyurethane foam (PUF) disk type samplers at 97 sites and surface soil samples were collected in a subset of 51 sites in the same year. As expected, the air concentrations (pg m(-3)) were highest at urban sites (mean of 350 +/- 218) followed by rural (230 +/- 180) and background sites (77 +/- 50). The PCB homologue composition was similar across China, with no distinction among site types, and reflected the profile of Chinese transformer oil with a greater proportion of lower molecular weight (LMW) congeners, particularly the tri-PCBs. This differs from the profile in Chinese soil that was shifted toward the higher molecular weight (HMW) congeners and likely attributed to numerous years of deposition and accumulation in this reservoir. The PCB profile in surface soil also reflects an "urban fractionation effect" with preferential deposition of HMW congeners near sources. The profile of PCBs in Chinese air was shown to be different than reported for Europe and for the Great Lakes Area (GLA) in North America. European and GLA air samples show a distinction between urban and rural/V background sites, with urban sites dominated by tetra- and penta-PCBs, whereas rural and background sites are shifted toward LMW congeners. European and GLA samples also exhibit much higher PCB concentrations at urban sites. This may be attributed to the use of PCBs in building materials in European and North American cities. In China, the difference between urban and rural/background sites is less pronounced. Strong soil-air correlations were found for the LMW PCBs at the background and rural sites, and for the HMW PCBs at the urban sites, a strong evidence of the urban fractionation effect. To our knowledge, this is the first national-scale study in China investigating PCBs in both air and surface soil samples.

Accumulation parameters and seasonal trends for PCBs in temperate and boreal forest plant species

The concentration of polychlorinated biphenyls (PCBs) in the air and vegetation was measured periodically in two alpine forests, during the growing season. Foliage samples from nine plant species typical of the temperate and boreal environment were collected and analyzed. Leaf concentrations of tri- and tetra-CBs showed fast response times with changing temperature and gas-phase concentrations, suggesting that a partitioning equilibrium is approached relatively rapidly (few days) in the field. Heavier compounds showed kinetically limited accumulation trends, not reaching equilibrium during the growing season. Results were used to estimate the bioconcentration factors or equilibrium plant/air partition coefficient (KPA) for each species. Values of log KPA (calculated on a mass/volume basis) ranged between 0.78 and 1.96 and were correlated to the log KOA. Uptake trends of the higher chlorinated compounds showed intraspecific differences which were partially explained by the specific leaf area (SLA).

Field derived accumulation and release kinetics of DDTs in plants

Vegetation plays an important role in influencing the air/surface exchange of semivolatile organic compounds (SOCs). In order to predict the capability of different plant species to capture chemicals from the air, plant-air partition coefficients and kinetic accumulation parameters must be defined. In this study, potted plants of three different species were transferred to the vicinity of a source point for DDT, namely a contaminated area around a former production plant in Italy. Leaves were constantly sampled in order to follow the uptake from air over time. Later, the potted plants were transported to a location characterized by background diffuse air concentrations for the release phase. Coupling the experimental results with a two-compartment accumulation model it was possible to derive the kinetics parameters and the plant-air partition coefficient K(PA) for p,p'-DDT. The logK(PA) (on a mass/volume basis) ranged between 1.7 and 2.2 for the different species. The uncertainties related to the different phenomena involved in a field uptake/release experiment are discussed.

Polybrominated diphenyl ethers: causes for concern and knowledge gaps regarding environmental distribution, fate and toxicity

This manuscript critically considers several areas of study of the polybrominated diphenyl ether compounds. Specifically, a brief review of PBDE toxicity is followed by an in depth discussion of PBDE occurrence in abiotic and biotic environmental matrices. Temporal and geographic trends are examined in conjunction with risk assessment factors. Rather than summarize or tabulate the growing body of literature on PBDEs in the environment, the overall goal of this review paper is to highlight broad patterns that may contribute to a more holistic understanding of PBDE behavior in the environment, as well as to identify critical areas of research that warrant further attention.

Atmospheric input of POPs into Lake Maggiore (Northern Italy): PBDE concentrations and profile in air, precipitation, settling material and sediments

Large lakes are sinks for many chemical pollutants but the role of the atmosphere in delivering PBDEs (polybrominated diphenyl ethers) is not well known. In this study we estimated inputs of PBDEs from the atmosphere to Lake Maggiore and the delivery via settling material to accumulated bottom sediments. Sampling consisted of one simultaneous week of air and bulk deposition during Spring 2005, an integrated 4-month period of collected settling material (via sediment trap), and superficial bottom sediments near the sediment trap deployment and tributary mouths of the lake. Concentration of total PBDEs (Sigma 8) in the sediments ranged between 0.06 and 27 ng g(-1), and two different patterns were observed. One pattern was dominated by BDE-47 and BDE-99 and a second by BDE-209. The latter pattern suggested input from local source(s). Total PBDEs in air were 107 pg m(-3) with a pattern dominated by BDE-47. The bulk deposition rate of total PBDEs for precipitation was measurated to be 17.6 ng m(-2) day(-1) where BDE-209 exhibited the highest concentration. For aquatic settling material the flux was 3.57 ng m(-2) day(-1) and was dominated by congeners BDE-47 and BDE-99. The bulk deposition and settling material fluxes were in the same range for the less brominated congeners, while for the hepta- and deca-brominated PBDEs the fluxes in the settling material were one order of magnitude lower. This suggests different sedimentation processes among congeners and/or the presence of local sources that influence the relative distribution in water column.

Modeling the importance of biota and black carbon as vectors of polybrominated diphenyl ethers (PBDEs) in the Baltic Sea ecosystem

The POPCYCLING-Baltic model, a nonsteady state spatially resolved mass balance model of chemical transport in the Baltic Sea environment was modified to include black carbon (BC), dissolved organic carbon (DOC) and food-web bioaccumulation. The importance of these modifications to the transport of PBDE congeners BDE-47, -99, -153, and -209 was assessed by comparing time-series simulated with and without black carbon and biota between 1970 and 2005. Inclusion of black carbon improved the model fit to measurements from air, soil, and biota, and had a major effect on the mass balance. Modeled bulk concentrations of PBDEs in sediments and soils increased by a factor of 3 while concentrations in biota decreased by a factor of 2-5. Black carbon also doubled the recovery time of the system due to the limited availability of PBDEs for degradation. In comparison, the inclusion of biota had only a minor effect on the overall mass balance and recovery times. The modified model is constructed as a flexible matrix and can also be applied to persistent organic pollutants in other ecosystems besides the Baltic Sea.

A GIS-based approach for modeling the fate and transport of pollutants in Europe

This paper presents an approach to estimate chemical concentration in multiple environmental media (soil, water, and the atmosphere) with the sole use of basic geographical information system (GIS) operations and, particularly, map algebra. This allows solving mass balance equations in a different way from the traditional methods involving numerical or analytical solution of systems of equations, producing maps of chemical fluxes and concentrations only through combinations of maps of emissions and environmental removal or transfer rates. Benchmarking with the well-established EMEP MSCE-POP model shows that the method provides consistent results with this more detailed description. When available, experimental evidence equally supports the proposed method in relation to the more complex approaches.