Elevation of intracellular free calcium levels in sperm in response to long-term feeding of fungicides to mice.

To assess the impact of long-term feeding of fungicides on sperm quality, mice were fed a daily diet containing a mixture of maneb and zineb, at concentrations of 30, 300, and 3000 ppm, respectively. Employing epididymal sperm suspended in a medium permitting in vitro capacitation, the intracellular free Ca2+ concentration, [Ca2+]i, was determined with a fluorescent Ca2+ indicator, Fura-2. Regardless of the fungicide dosages applied, [Ca2+]i was about 50 percent higher in treated animals relative to a value of 123 nM [Ca2+]i in the control group. Fungicide-treated mice were mated to mature, non-treated females; as in the control, the litter sizes were the same. In conclusion, the observed elevation in [Ca2+]i seems to reflect cellular adaptation responses to toxic stress at moderate fungicide doses.     

Uptake of aluminum by lipid vesicles

Aluminium uptake and tight binding were studied in multilayered phospholipid liposomes, as a model for cellular uptake of aluminum ions. Most of these studies were conducted with an initial aluminum concentration of 10 μM, while aluminum superficially bound to liposomes was removed by citrate chelation. Maximum uptake and tight binding of aluminium were pH‐dependent. In dimyristoyl phosphatidylcholine (DMPC) liposomes, this maximum occurred in the neutral pH region, while it was shifted towards more acidic pH values in DMPC liposomes containing 20% of acidic phosphatidylserine. The initial rate of aluminum uptake was apparently dependent on the physical state of the liposome membrane. Prior formation of an aluminum‐citrate chelate prevented aluminum uptake and tight binding to DMPC liposomes.     

Persistent organic pollutants (POPs) in human milk: A biomonitoring study in rural areas of Flanders (Belgium)

To collect information on the concentrations of persistent organic pollutants (POPs) in the rural areas in Flanders (Belgium), 84 breastfeeding mothers were recruited in rural communities in East and West Flanders and Flemish Brabant in 2009-2010. Polychlorinated biphenyl (PCB) congeners, organochlorine pesticides, brominated flame retardants, perfluorinated compounds, polychlorinated dibenzodioxines and dibenzofurans, and dioxin-like PCBs were measured in individual milk samples and in a pooled milk sample, while some additional pollutants were only measured in the pooled sample. For most pollutants, the concentrations in this study were lower or comparable to the concentrations measured in the pooled Belgian sample of the WHO human milk study of 2006, except for the pesticides dichlorodiphenyltrichloroethane DDT (+25% for ΣDDT and metabolites) and trans-nonachlor (+94%), and for the brominated flame retardant hexachlorocyclododecane HBCD (+153%). Perfluorinated compounds were for the first time determined in human milk samples from Belgium and the concentrations were comparable to those from other European countries. Also, interesting associations were found between the concentrations of POPs measured in human milk and personal characteristics as well as dietary habits of the study population. PFOS en PFOA concentrations were significantly higher in milk of primiparous participants compared to mothers who gave birth to their second child. Lower brominated PBDE congeners increased with increasing BMI of the mothers (p = 0.01 for BDE 47, p = 0.02 for BDE 99 and p = 0.02 for BDE 100). Participants consuming milk or dairy products daily had significant higher concentrations of ΣDDTs (p = 0.03) and oxychlordane (p = 0.047) in their human milk samples.     

Toxaphene in minke whales (Balaenoptera acutorostrata) from the North Atlantic

Toxaphene contamination of minke whales (Balaenoptera acutorostrata) from North Atlantic waters was examined for the first time. Total toxaphene and SigmaCHB (sum of 11 chlorobornanes) concentrations in blubber samples ranged from 170+/-110 and 41+/-39 ng/g lipid weight (l.w.) for female minke whales from southeastern Greenland to 5800+/-4100 and 1100+/-780 ng/g l.w. for males from the North Sea, respectively. Very large variations in toxaphene concentrations among sampling areas were observed suggesting a spatial segregation of minke whales. However, much of the apparent geographical discrimination was explained by the seasonal fluctuation of animal fat mass. Patterns of CHBs in males revealed that recalcitrant CHBs were in higher proportions in animals from the more easterly areas than in animals from the more westerly areas. This trend may be influenced by the predominance of the US, over the European, input of toxaphene to North Atlantic waters.     

Comparison of GC and LC determinations of hexabromocyclododecane in biological samples - results from two interlaboratory comparison studies

In order to assess the quality and comparability of results from determinations of 1,2,5,6,9,10-hexabromocyclododecane (HBCD) in biological samples, two interlaboratory comparison studies have been organized. Up to 13 laboratories determined either the total HBCD concentration, or concentrations of alpha-, beta- and gamma-HBCD, or both in cod liver oil, herring filet, salmon filet, butter and chicken meat. The laboratories were able to determine total HBCD concentrations in the marine samples with satisfying quality (RSD <35%). However, the analysis of samples with low HBCD contamination (相似文献   

Tradable permits without legislative targets: a review of the potential for a permit scheme for sterilized clinical waste in the UK.

Tradable-permit schemes are becoming an increasingly popular technique for encouraging materials recovery and the diversion of waste from landfill. Such schemes operate using various forms of market-based trading of waste permits between polluters but usually rely on mandatory recycling targets to provide an incentive for trading. Using the UK's Packaging Recovery Note (PRN) scheme as a template, this paper examines the potential for permit trading where mandatory targets are absent and schemes must be driven solely by the financial benefits of reduced landfill costs and permit/material sales. The case examined is sterilized clinical waste, which has considerable recycling potential but suffers from health concerns and a poor public image. Interviews with healthcare and waste-management representatives indicate that although elements of the PRN scheme might prove appropriate for encouraging materials recovery, the absence of government targets and uncertain end markets for sterilized clinical waste present major obstacles to trading. Alternative incentives would therefore be required to catalyse schemes and develop recycling infrastructure. In the final analysis, thermal processing may be a more practical alternative to landfill than materials recovery for this particular waste stream.     

Comparability of world-wide analytical data of PCDDs, PCDFs and non-ortho PCBs in samples of chicken, butter and salmon

It was the primary objective of the present study to elucidate, from a chemical analytical point of view, the comparability of dioxin determinations and the consequences concerning the data on levels in food reported world-wide. To do so, an international intercalibration study on the determination of polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and dioxin-like PCBs in three natural food items was performed between March and June 2000. Samples of chicken, butter and salmon, collected in Norway, where sent to 42 laboratories and analysed for 20 PCDDs/PCDFs/non-ortho PCBs. The study generated congener-specific data for the three food matrixes both on wet weight and lipid basis. The reported data from 37 laboratories, in 15 countries, were statistically analysed in order to determine the congener-specific comparability as well as the comparability based on a toxic equivalency value (TEQ). Based on the reported data the mean relative standard deviations (mean RSD) for the WHO98-TEQDFP measurements were found to range from 36% to 57% the three foods. For chicken, the consensus level was 1.2 ppt TEQ on lipid basis, and the reported levels by 24 laboratories were between 0.53 and 2.2 ppt. For butter, the consensus was 0.55 ppt TEQ. 27 laboratories reported levels from 0.18 up to 1.5 ppt. For the salmon, sample levels of 5.9 to 38 ppt TEQ (by 25 laboratories) was reported where 15 ppt was the consensus value. It can thus be concluded that the world-wide data on dioxins, at background levels in foods, are not direct numerically comparable due to inherent analytical reasons. Up to 50% deviations are expected when interlaboratory dioxin results for foods are compared.