Bioaccumulation of organochlorine pesticides from contaminated soil by cattle

The study aimed to quantitate the uptake by beef cattle of organochlorine pesticides in from soil. Although such uptake is known to occur, uptake rates have not been accurately measured for these animals and cannot be inferred from data obtained with dairy cattle. In this study, cattle received a diet, of a standard feedlot ration supplemented with organochlorine-pesticide (aldrin?+?dieldrin) contaminated soil. The levels of pesticides in the feed would approximate uptake through normal grazing. Samples of the subcutaneous fat were removed periodically and analysed for pesticide content. Uptake of dieldrin (but not other pesticides present in the soil) was rapid and substantial. Uptake from sandy soils was more efficient than that from clay soils. The experiment was terminated after 8 weeks, because of the high levels of dieldrin in the tissues. Depuration of the accumulated pesticides was a slow and complex process, requiring a longer period than accumulation.     

PCB 105-induced ultrastructural alterations in the rat liver: A stereological study

Liver alterations were stereologically determined in five groups, each of 10 male and female Sprague–Dawley weanling rats fed PCB 105 (2,3,3′,4,4′-pentachlorobiphenyl) for 13 weeks at concentrations of 0.05, 0.5, 5, and 50?ppm mixed with corn oil. Animals from two groups receiving the oil in diets served as controls for each gender. A significant increase in mean volume fraction (VF) of smooth endoplasmic reticulum (SER) profiles was estimated in hepatocytes of female rats in 0.5, 5, and 50?ppm groups. A significant decrease in VF of mitochondria in female rats at 50?ppm was detected. In addition, a decrease in VF of lipid droplets was measured in female rats at 0.5, 5, and 50?ppm groups. No difference was found in VF of rough endoplasmic reticulum (RER) cisternae, and peroxisome profiles at any concentration of the PCB in either male or female animals as compared to baseline values from controls. A significant elevation of baseline VF for RER in female rats was detected in comparison with males. In the present study, no observable adverse effect level (NOAEL) for PCB 105 was estimated at <0.5?ppm for hepatocyte alterations in female Sprague–Dawley rats.     

Prostaglandin F2α facilitates female mating behavior based on male performance

Hormones play an important role in the regulation of reproductive behavior. Here, we examined the effects of the fatty acid derivative prostaglandin F2α (PGF2) on female sexual behavior as well as the interaction between PGF2-induced mating behavior with male courtship display in the lek-breeding African cichlid fish, Astatotilapia burtoni. In a two-way choice paradigm, we found that nonreproductive females preferred to associate with smaller, less aggressive males over larger, more aggressive males. However, PGF2-treated females dramatically reversed their preference to larger males. In a second experiment, PGF2 treatment dramatically increased sexual behavior in nonreproductive females as measured by time spent in the bower of the stimulus male, even when the female and the stimulus male were separated by a transparent divider. This effect was even more pronounced when the stimulus males were exposed to the putative female pheromone 17α,20β-progesterone (17α,20β-P). Under full-contact conditions, only PGF2-treated females visited a stimulus male’s bower, where they even displayed circling behavior usually only seen during spawning. Interestingly, male performance prior to PGF2 treatment predicted female sexual response. Our study demonstrates the importance of PGF2 in the control of female reproductive behavior in interaction with male performance.     

Evidence for the presence of a widespread PCDD source in coastal sediments and soils from Queensland, Australia

Recent studies have demonstrated the occurrence of elevated levels of higher chlorinated PCDDs in the coastal environment of Queensland, Australia. This study presents new data for OCDD contamination and full PCDD/F profile analysis in the environment of Queensland. Marine sediments, irrigation drain sediments and topsoil were collected from sites that were expected to be influenced by specific land-use types. High OCDD concentrations were associated mainly with sediments collected near the mouth of rivers which drain into large catchments in the tropical and subtropical regions. Further, analysis of sediments from irrigation drains could be clearly differentiated on the basis of OCDD contamination, with high concentrations in samples from sugarcane drains collected from coastal regions, and low concentrations in drain sediments from drier inland cotton growing areas. PCDD/F congener-specific analysis demonstrated almost identical congener profiles in all samples collected along the coastline. This indicates the source to be widespread. Profiles were dominated by higher chlorinated PCDDs, in particular OCDD whereas 2,3,7,8-substituted PCDFs were below the limit of quantification in the majority of samples. The full PCDD/F profile analysis of samples strongly resemble those reported for lake sediments from Mississippi and kaolinite samples from Germany. Strong similarities to these samples with respect to congener profiles and isomer patterns may indicate the presence of a similar source and/or formation process that is yet unidentified.     

PAHs, PCDD/Fs, PCBs and HCB in leaves from Brisbane, Australia

The concentrations of SOCs in leaves of an evergreen Australian native tree (Melaleuca leucadendra) and grass collected in Brisbane, Australia were determined. The concentrations of PCDD/Fs and PAHs in the leaf tissue were comparable to those reported for urbanised areas in other industrialised countries. A distinct difference in the compound profiles between the leaves of the two species was observed, with higher concentrations of the lower molecular mass PAHs and PCDD/Fs and lower concentrations of the higher molecular mass PAHs and PCDD/Fs in the Melaleuca leaves relative to the grass leaves. The interspecies differences are explained on the basis of the larger size of the lipophilic compartment (for compounds with low K(OA)) and the lower ratio of surface area to volume in the Melaleuca leaves.