Polybrominated diphenyl ethers (PBDEs) in farmed and wild salmon marketed in the Northeastern United States

Recently, we reported on the analysis of polychlorinated biphenyls (PCBs) and chlorinated pesticides in farmed Atlantic salmon (Salmo salar) from Maine, eastern Canada, and Norway, and wild Alaskan Chinook salmon (Oncorhynchus tshawytscha). In this paper, we extend the analysis to polybrominated diphenyl ethers (PBDEs) in these samples. Total PBDE concentrations in the farmed salmon (0.4-1.4ng/g, wet weight, ww) were not significantly different from those in the wild Alaskan Chinook samples (0.4-1.2ng/g, ww), nor were significant differences found among regions. However, significant intra-regional variations in concentrations of total PBDEs and tetra-BDE 47 were observed in the salmon from the Canadian farms (p<0.01). Congener profiles were dominated by BDE-47, followed by the penta-BDEs 99 and 100. PBDE concentrations in the Canadian samples were lower than those reported two years earlier. Removal of skin resulted in no overall reduction in PBDE concentrations in our farmed salmon, and in some cases, PBDE concentrations were higher in skin-off samples. PBDEs were correlated with lipids only in the skinned samples, suggesting that there is greater accumulation and retention of PBDEs in muscle lipids than in skin-associated fat. In skin-on samples, modest correlations were observed between concentrations of PBDEs and PCBs (R(2)=0.47) and mono-ortho PCBs (R(2)=0.50), whereas PBDEs were not correlated with non-ortho PCBs.     

Novel evidence for natural formation of dioxins in ball clay

Elevated concentrations of dioxins in ancient ball clay from the Mississippi Embayment suggest natural formation of dioxins in the environment. Evidence for such natural formation in ball clay derives from unique congener profiles in undisturbed ancient clay deposits and from the lack of other anthropogenic contaminants. Here we present novel evidence of natural formation of dioxins based on congener-specific carbon isotopic analysis of octachlorodibenzo-p-dioxin (OCDD) in ball clays from the USA and Japan. The analyses were performed using a combination of double-column high performance liquid chromatography clean-up and two-dimensional gas chromatography-isotope ratio mass spectrometry. Elevated concentrations of OCDD found in ball clays from the USA and Japan were isotopically distinguished from the anthropogenic source materials (fly ash and pentachlorophenol) and environmental samples (sediment and soil). The isotopic signatures and the occurrence of OCDD in ancient ball clays deposited in the Tertiary Era provide evidence for the in situ formation of dioxins.     

An innovative approach to minimize excess sludge production in sewage treatment using integrated bioreactors

The present investigation deals with an application of integrated sequential oxic and anoxic bioreactor(SOABR) and fluidized immobilized cell carbon oxidation(FICCO) reactor for the treatment of domestic wastewater with minimum sludge generation. The performance of integrated SOABR-FICCO system was evaluated on treating the domestic wastewater at hydraulic retention time(HRT) of 3 hr and 6 hr for 120 days at organic loading rate(OLR)of 191 ± 31 mg/(L·hr). The influent wastewater was characterized by chemical oxygen demand(COD) 573 ± 93 mg/L; biochemical oxygen demand(BOD5) 197 ± 35 mg/L and total suspended solids(TSS) 450 ± 136 mg/L. The integrated SOABR-FICCO reactors have established a significant removal of COD by 94% ± 1%, BOD5 by 95% ± 0.6% and TSS by 95% ± 4% with treated domestic wastewater characteristics COD 33 ± 5 mg/L; BOD59 ± 0.8 mg/L and TSS 17 ± 9 mg/L under continuous mode of operation for 120 days. The mass of dry sludge generated from SOABR-FICCO system was 22.9 g/m~3. The sludge volume index of sludge formed in the SOABR reactor was 32 mL/g and in FICCO reactor it was 46 mL/g. The sludge formed in SOABR and FICCO reactor was characterized by TGA, DSC and SEM analysis. Overall, the results demonstrated that the integrated SOABR-FICCO reactors substantially removed the pollution parameters from domestic wastewater with minimum sludge production.     

Pesticide modelling for a small catchment using SWAT-2000

Pesticides in stream flow from the 142 ha Colworth catchment in Bedfordshire, UK were monitored from October 1999 to December 2000. About 47% of the catchment is tile-drained and different pesticides and cropping patterns have recently been evaluated in terms of their effect on nutrient and pesticide losses to the stream. The data from Colworth were used to test soil and water assessment tool (SWAT) 2000 predictions of pesticide concentrations at the catchment outlet. A sound model set-up to carry out pesticide modelling was created by means of hydrological modelling with proper simulation of crop growth and evapotranspiration. The pesticides terbuthylazine, terbutryn, cyanazine and bentazone were modelled. There was close agreement between SWAT-predicted pesticide concentration values and observations. Scenario trials were conducted to explore management options for reducing pesticide loads arriving at the catchment outlet. The results obtained indicate that SWAT can be used as a tool to understand pesticide behavior at the catchment scale.     

Water quality and phytoplankton characteristics in the Palk Bay, southeast coast of India

The present study was carried out to determine the water quality in terms of physicochemical characteristics and plankton distribution in the coastal waters of Kattumavadi, Palk Bay for a period of one year from April 2002 to March 2003. Air and surface water temperatures varied from 28 degrees C to 32.50 degrees C and from 27.5 to 32.0 degrees C while light extinction coefficient (LEC) varied between 0.95 and 1.85. Salinity ranged from 26.0 to 34.5 per thousand and the pH ranged between 7.95 and 8.35. Variation in dissolved oxygen content was from 4.15 to 7.18 ml(-1), and the particulate organic carbon (POC) content varied between 0.49 and 2.28 mgCl(-1). Concentrations of nutrients viz. nitrate (2.15 to 8.28 microM), nitrite (0.12 to 0.62 microM), inorganic phosphate (1.28 to 2.15 microM) and reactive silicate (5.15 to 12.52 microM) also varied independently. Chlorophyll a content ranged from 0.28 to 1.48 mg m(-3) and the primary productivity, from 4.19 to 16.08 mgCm(-3) hr(-1). The present study recorded a total of 43 species of planktonic diatoms and two species of blue-green algae. Population density of phytoplankton varied from 18,000 to 34,000 cells l(-1). Percentage composition, of the diatoms showed minimum values during the monsoon season and the maximum values during the premonsoon season.     

Butyltin compounds in sediment and fish from the Polish Coast of the Baltic Sea

Concentrations of mono- (MBT), di- (DBT), and tri-(TBT) butyltin compounds were measured in eggs, liver, and muscle of nine species of fish from four regions of the Baltic Sea - the Firth of Vistula, the Gulf of Gdańsk, Puck Bay, and the mouth of the Vistula River. The overall concentration ranges among all the fish sampled from the four sites were: < 7 to 79 ng/g for MBT, 6 to 1100 ng/g for DBT, 7 to 3600 ng/g for TBT, and 16 to 4800 ng/g for total BTs, on a wet wt basis. The highest concentration of total BTs was found in herring liver from the Firth of Vistula (4800 ng/g, wet wt) and in roach muscle from Puck Bay (3300 ng/g, wet wt), while the least concentration was found in burbot eggs and liver from the Vistula River (39 and 32 ng/g, wet wt, respectively). TBT was the major form of BTs present in most samples analyzed. Sediment samples collected from shipyards in the Gulf of Gdańsk contained butyltin concentrations ranging from 1.2 to 46 μg/g (dry wt) for MBT, 2.0 to 42 μg/g for DBT, and 2.6 to 40 μg/g for TBT. As with the fish, the majority of the BTs in sediment were present as TBT, which suggested recent exposure of the aquatic environment of the region to TBT.     

DNA repair gene polymorphisms at XRCC1, XRCC3, XPD, and OGG1 loci in Maharashtrian population of central India

Reduction in DNA repair capacity is associated with increased rates of birth defects, cancer, and accelerated ageing. Genetic polymorphisms in DNA repair genes might influence the repair activities of the enzymes predisposing individuals to cancer risk. Owing to the presence of these genetic variants, inter-individual and ethnic differences in DNA repair capacity have been observed in various populations. India harbors enormous genetic, cultural and linguistic diversity. The present study was undertaken to determine the allele and genotype frequencies of four non-synonymous SNPs, XRCC1 Arg399Gln (C > T, rs25487), XRCC3 Thr241Met (G > A, rs861539), XPD Lys751Gln (T > G, rs13181), and OGG1 Ser326Cys (C > G, rs1052133) in the Maharashtrian population, residing in the Vidarbha region of central India and to compare them with HapMap and other Indian populations. The variant alleles of these polymorphisms have been found to be positively associated with different forms of cancer in several genetic epidemiological studies. The basic prevalence of these polymorphisms in the general population must be known to evaluate their significance in risk assessment in cancer and other phenotypes. About 215 healthy and unrelated individuals from the Maharashtrian population were genotyped for each of these four polymorphisms using PCR-RFLP. The allele and genotype frequency distribution at the four DNA repair gene loci among Maharashtrians revealed a characteristic pattern. To the best of our knowledge, this is the first report of these DNA repair gene polymorphisms in a central Indian population.     

Clam‐sediment accumulation factors for polychlorinated biphenyl congeners at a contaminated estuarine marsh

Clam‐sediment accumulation factors for hexa‐, hepta‐ and octa‐chlorobiphenyls were estimated at an intertidal marsh that has been contaminated with Aroclor 1268. Accumulation factors for PCB congeners with K _ow > 6.5 were in the range of 0.07–0.88, indicating that their uptake was hindered by steric factors, contamination levels, non‐equilibrium conditions and stronger affinity to sediment organic carbon. Biota‐sediment accumulation factors (BSAFs) were negatively correlated with log K _ow of superhydrophobic PCB congeners. BSAFs estimated based on 2,3,7,8‐TCDD equivalents of PCBs were 2‐fold greater than those derived from total PCB concentrations.     

Organochlorine pesticides and polychlorinated biphenyls in California sea lions

Concentrations of polychlorinated biphenyls (PCBs), DDTs, chlordanes, HCHs, hexachlorobenzene (HCB), dieldrin, heptachlor epoxide, tris(4-chlorophenyl)methane (TCPMe), and tris(4-chlorophenyl)methanol (TCPMOH) were measured in the blubber of California sea lions (Zalophus californianus) collected in 2000. DDTs were the most predominant contaminants, followed by PCBs, chlordanes, TCPMe, HCHs, TCPMOH, dieldrin, and heptachlor epoxide. Concentrations of PCBs and DDTs varied from a few microg/g to several hundreds of microg/g on a lipid weight basis. Concentrations of DDTs have declined by an order of magnitude over the last three decades in California sea lions; nevertheless, the measured concentrations of PCBs and DDTs in California sea lions are still some of the highest values reported for marine mammals in recent years. Concentrations of organochlorines were highly correlated with one another. Concentrations of PCBs and DDTs in the blubber of gray whale, humpback whale, northern elephant seal, and harbor seal, and in the adipose fat of sea otter, were lower than the levels found in California sea lions, and were in the range of a few to several microg/g on a lipid weight basis.