Perfluorinated chemicals in relation to other persistent organic pollutants in human blood

In order to evaluate blood levels of some perfluorinated chemicals (PFCs) and compare them to current levels of classical persistent organic pollutants (POPs) whole blood samples from Sweden were analyzed with respect to 12 PFCs, 37 polychlorinated biphenyls (PCBs), p,p'-dichlorodiphenyl-dichloroethylene (DDE), hexachlorobenzene (HCB), six chlordanes and three polybrominated diphenyl ethers (PBDEs). The median concentration, on whole blood basis, of the sum of PFCs was 20-50 times higher compared to the sum of PCBs and p,p'-DDE, 300-450 times higher than HCB, sum of chlordanes and sum of PBDEs. Estimations of the total body amount of PFCs and lipophilic POPs point at similar body burdens. While levels of for example PCBs and PBDEs are normalized to the lipid content of blood, there is no such general procedure for PFCs in blood. The distributions of a number of perfluorinated compounds between whole blood and plasma were therefore studied. Plasma concentrations were higher than whole blood concentrations for four perfluoroalkylated acids with plasma/whole blood ratios between 1.1 and 1.4, whereas the ratio for perflurooctanesulfonamide (PFOSA) was considerably lower (0.2). This suggests that the comparison of levels of PFCs determined in plasma with levels determined in whole blood should be made with caution. We also conclude that Swedish residents are exposed to a large number of PFCs to the same extent as in USA, Japan, Colombia and the few other countries from which data is available today.     

Brominated flame retardant concentrations and trends in abiotic media

BFR burdens in abiotic media have been less studied than in biota, despite their essential value as an aide to identifying sources, temporal and geographic trends and exposure routes. Many polymer products consist of several percent by weight of BFRs. Global trade in these can result in rapid and wholesale BFR movement. Loss from in-use products of nonreactive BFRs may be important, particularly in respect to indoor exposure. In the case of BDE-209, discharges from publicly owned treatment works may be substantial. BFR burdens in air, water and sewage sludge respond rapidly to changes in environmental BFR inputs. PBDEs have been the most widely studied. In many locales PBDE burdens in these media now surpass those of PCBs. Air and water near sources and urban areas are typically enriched relative to rural locales. The more volatile PBDEs dominate in the vapor phase, while BDE-209 typically predominates on particulates. Evidence exists for long-range transport of the more volatile PBDEs. A greater diversity of BFRs (mostly PBDEs, HBCD and TBBP-A) has been detected in sewage sludges. Land application of these sludges on agricultural fields is one conduit for soil contamination. In general, environmental concentrations of BDE-209 appear to be increasing, while penta-BDE burdens in Europe may have peaked. Sediments function as longer-term integrators of environmental burdens. Concentrations of common BFRs therein may be substantial near point sources. Evidence for debromination in the environment has been limited to date. However, some laboratory and field observations suggest it is possible to a limited extent.     

Sources and fate of butyltins in the St. Lawrence Estuary ecosystem

Butyltins (BTs) were determined in sediment, zooplankton, benthic fish and invertebrates in the St. Lawrence Estuary and its mixing zone with the Gulf of St. Lawrence (Canada) in an attempt to assess sources and fate of these compounds in a large ecosystem before the enforcement of the world-wide ban of TBT-based antifouling paints. All BTs (MBT, DBT and TBT) were found along the studied area (450 km) where the traffic of large vessels occurs around the year. Concentrations of total butyltins (BTs) in surface sediment were below 6 ng Sn g(-1) d.w. Total BTs concentrations found in zooplankton samples at the mouth of the Saguenay Fjord were the highest (793 ng Sn g(-1) d.w.), indicating the influence of the Fjord on the St. Lawrence contamination. Although a relatively low contamination level was measured in sediment, total BTs concentrations ranged from 9 to 489 ng Sn g(-1) d.w. for benthic organisms. Biota-sediment accumulation factors (BSAFs), calculated on the basis of the organic carbon content in the sediment (concentrations normalized to 1% Corg), ranged from 0.9 to 98.3, and are an indicator of an important source of BTs from the Saguenay Fjord particulate matter. This may be explained by the fact that when TBT is released in a large and deep well stratified coastal environment, it could bind to the suspended particulate matter and then be taken in charge by water column organisms and may be mostly metabolised before it reaches bottom sediment. Sediment is not considered as the main contributor to the contamination of fish and invertebrates. It is expected that any reduction of direct inputs of TBT from ship hulls in a near future should result in a rapid reduction of butyltins in the St. Lawrence ecosystem.     

Serum PCBs and organochlorine pesticides in Slovakia: age, gender, and residence as determinants of organochlorine concentrations

We measured organochlorine concentrations of 15 polychlorinated biphenyl congeners and six organochlorine pesticides (PCB28, 52, 101, 123(+149), 118, 114, 153, 105, 138(+163), 167, 156(+171), 157, 180, 170, 189, alpha-, beta-, gamma-HCH, HCB, p,p'-DDT and p,p'-DDE) in 2047 subjects from contaminated and background areas of eastern Slovakia. Data were collected in 2001 and analyzed by high-resolution gas chromatography with electron capture detection in 2002-2003. Elevated levels persist in subjects from Michalovce district, site of former production facility, after almost 20-years since the end of the PCB manufacturing. Sum of 15 PCB congeners was 3105 ng/g of lipid in the Michalovce district versus 871 ng/g of lipid for subjects from the background districts of Svidnik and Stropkov. Relatively high concentration in children from the Michalovce district, sum PCB = 766 ng/g of lipid versus 372 ng/g of lipid in children from background area suggest ongoing exposure from environmental reservoirs and contaminated food. Consistent differences between genders in both contaminated and background areas are reported here. Levels in males are about 20% higher in both districts. Levels of organochlorine pesticides, particularly of DDT metabolite DDE and hexachlorobenzene are also elevated in the Michalovce district, reflecting intensive use of pesticides in agriculture in the past. About 30% decrease in serum organochlorine levels was observed in comparison with our earlier samples collected in 1998. These results suggest that contamination with PCBs still remains a source of relatively high environmental exposure for subjects in the Michalovce district.     

Probabilistic study of well capture zones distribution at the Lauswiesen field site

The delineation of well capture zones is of utmost environmental and engineering relevance as pumping wells are commonly used both for drinking water supply needs, where protection zones have to be defined, and for investigation and remediation of contaminated aquifers. We analyze the probabilistic nature of well capture zones within the well field located at the "Lauswiesen" experimental site. The test site is part of an alluvial heterogeneous aquifer located in the Neckar river valley, close to the city of Tübingen in South-West Germany. We explore the effect of different conceptual models of the structure of aquifer heterogeneities on the delineation of three-dimensional probabilistic well catchment and time-related capture zones, in the presence of migration of conservative solutes. The aquifer is modeled as a three-dimensional, doubly stochastic composite medium, where distributions of geo-materials and hydraulic properties are uncertain. We study the relative importance of uncertain facies geometry and uncertain hydraulic conductivity and porosity on predictions of catchment and solute time of travel to the pumping well by focusing on cases in which (1) the facies distribution is random, but the hydraulic properties of each material are fixed, and (2) both facies geometry and material properties vary stochastically. The problem is tackled within a conditional numerical Monte Carlo framework. Results are provided in terms of probabilistic demarcations of the three-dimensional well catchment and time-related capture zones. Our findings suggest that the uncertainty associated with the prediction of the location of the outer boundary of well catchment at the "Lauswiesen" site is significantly affected by the conceptual model adopted to incorporate the heterogeneous nature of the aquifer domain in a predictive framework. Taking into account randomness of both lithofacies distribution and materials hydraulic conductivity allows recognizing the existence of preferential flow paths that influence the extent of the well catchment and the solute travel time distribution at the site.     

A carbon budget of a small humic lake: an example of the importance of lakes for organic matter cycling in boreal catchments

Lakes play an important role in the cycling of organic matter in the boreal landscape, due to the frequently high extent of bacterial respiration and the efficient burial of organic carbon in sediments. Based on a mass balance approach, we calculated a carbon budget for a small humic Swedish lake in the vicinity of a potential final repository for radioactive waste in Sweden, in order to assess its potential impact on the environmental fate of radionuclides associated with organic matter. We found that the lake is a net heterotrophic ecosystem, subsidized by organic carbon inputs from the catchment and from emergent macrophyte production. The largest sink of organic carbon is respiration by aquatic bacteria and subsequent emission of carbon.dioxide to the atmosphere. Although the annual burial of organic carbon in the sediment is a comparatively small sink, it results in the build-up of the largest carbon pool in the lake. Hence, lakes may simultaneously disperse and accumulate organic-associated radionuclides leaking from a final repository.     

Increased thyroid volume and frequency of thyroid disorders signs in schoolchildren from nitrate polluted area

Thyroid volume (ThV) and echogenicity by ultrasound were estimated in 324 schoolchildren (aged between 10 and 13-years) from high nitrate area (HNA) located in agricultural lowland with high nitrate drinking water supply (51-274 mg/l) from shallow wells. The data were compared to children of the same age from low nitrate area (LNA) consisting of 168 children from the neighboring area with very low nitrate (< 2 mg/l) drinking water and of 596 children from the city of Kosice located in a vicinity of LNA and also supplied by low nitrate water. Blood samples were obtained from 315 willing children from HNA and 109 children from LNA and the levels of thyrotropin (TSH), total thyroxine (TT4), free triiodothyronine (FT3) and thyroperoxidase antibodies (anti-TPO) in serum were determined. ThV (mean +/- SE) in 10-year (5.10 +/- 0.14 ml) and 13-year (5.97 +/- 0.11 ml) old children from HNA was significantly higher than that in two groups of respective age from LNA, 4.58 +/- 0.17 (p < 0.02) and 5.23 +/- 0.15 ml (p < 0.05), and from the city of Kosice, 4.77 +/- 0.10 ml (p < 0.05) and 4.87 +/- 0.1 0ml (p < 0.0001). The frequency of hypoechogenicity in HNA was also significantly higher than that in pooled LNA plus Kosice, 13.7% vs. 4.7% (p < 0.01) in 10-year and 10.6% vs. 5.7% (p < 0.03) in 13-year, respectively. The frequency of TSH level in the range of subclinical hypothyroidism (> 4.0 mU/l) in pooled age groups from HNA was 13/324 (4.0%) and that of positive anti-TPO was 8/324 (2.5%), while no case of either increased TSH or positive anti-TPO was found in 109 children from LNA. Finally, no differences in the levels of TT4 and FT3 were found between HNA and LNA. It was concluded that long-term exposure to high nitrate intake by drinking water and home made meals from local products results in increased thyroid volume and increased frequency of signs of subclinical thyroid disorders (thyroid hypoechogenicity by ultrasound, increased TSH level and positive anti-TPO).     

Decolourization of synthetic dyes by Trametes hirsuta in expanded-bed reactors

The present paper studies the decolourization of different synthetic dyes (Indigo Carmine, Bromophenol Blue, Methyl Orange and Poly R-478) by the white-rot fungus Trametes hirsuta at bioreactor scale under solid-state conditions, operating with ground orange peelings as a support-substrate. Dye decolourization was performed in both batch and continuous mode. Batch cultivation led to high decolourization percentages in a short time (100% for Indigo Carmine in 3h and 85% for Bromophenol Blue in 7 h). As for continuous cultivation, different hydraulic retention times (HRT) were studied (0.8, 1, 1.5 and 3d). The highest decolourization percentages were obtained operating at a HRT of 3d, especially for the dyes Methyl Orange and Poly R-478 (81.4% and 46.9%, respectively). This is a very interesting result, since there are few studies dealing with the continuous decolourization of dyes at bioreactor scale by fungal laccases.     

Metal bioaccumulation and metallothionein concentrations in larvae of Crassostrea gigas

Larval stages of bivalve molluscs are highly sensitive to pollutants. Oysters from a hatchery from Normandy (English Channel) were induced to spawn, and fertilized eggs were exposed to copper or cadmium for 24 h. Metal accumulation (from 0.125 to 5 microg Cu L(-1) and from 25 to 200 microg Cd L(-1)) and MT concentrations were measured in larvae. Compared to controls, larvae accumulated copper and cadmium with an increase in MT concentrations particularly with cadmium (i.e. 130.96 ng Cu (mg protein)(-1) and 12.69 microg MT (mg protein)(-1) at 1 microg Cu L(-1) versus 23.19 ng Cu (mg protein)(-1) and 8.92 microg MT (mg protein)(-1) in control larvae; 334.3 ng Cd (mg protein)(-1) and 11.70 microg MT (mg protein)(-1) at 200 microg Cd L(-1) versus 0.87 ng Cd (mg protein)(-1) and 4.60 microg MT (mg protein)(-1) in control larvae). Larvae were also obtained from oysters of a clean area (Arcachon Bay) and a polluted zone (Bidassoa estuary) and exposed to copper in the laboratory, their MT concentration was measured as well as biomarkers of oxidative stress. Biomarker responses and sensitivity to copper for the larvae from Arcachon oysters were higher than for those from Bidassoa.     

Fine route for an efficient removal of 2,4-dichlorophenoxyacetic acid (2,4-D) by zeolite-supported TiO2

Zeolites HY, Hbeta and HZSM-5 with different physico-chemical properties were chosen as support for TiO2 to illustrate their adsorption, dispersion and electronic structure in photocatalysis. The extent of TiO2 loading was monitored by XRD and BET surface area measurements. The adsorption capacity of HY zeolite was found to be high and hence chosen for further modification to continue the investigation. Photodegradation kinetics were carried out with 2,4-dichlorophenoxyacetic acid (2,4-D) in aqueous solution. The extent of 2,4-D degradation on TiO2/HY loading revealed the importance of adsorption in photocatalysis. Mineralisation studies on all three zeolites with 1 wt.% TiO2 loading demonstrated the good dispersion properties of TiO2/HY. Its photocatalytic activity was found to be excellent with formulated 2,4-D. Comparison of relative photonic efficiencies demonstrated that supported photocatalysts exhibited higher activity than some of the commercial photocatalysts. The high activity of supported TiO2 is due to synergistic effects of improved adsorption of 2,4-D and efficient delocalisation of photogenerated electrons by zeolite support.