prunerbengal01
prunerbengal01
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Isiala ngwa South, Rivers, Nigeria
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Growing human populations and increasingly intensive agriculture have resulted in widespread aquatic nitrate pollution. Freshwater mussel populations have been in decline for decades but often are underrepresented in data used for the development of ambient water quality criteria and acute toxicity of nitrate to mussel glochidia has not yet been established. Additionally, toxicity testing with aquatic species often is limited to a few model species; however, relatively little is known about how representative model species are of imperiled species. Therefore, to better define the acute toxicity of nitrate to common and rare aquatic species, we conducted 24-h nitrate acute toxicity tests with glochidia of four species of freshwater mussels, including a federally threatened species (Hamiota altilis) and 7-day tests with larval fish of three species fathead minnow (Pimephales promelas), tricolor shiner (Cyprinella trichroistia), and tilapia (Oreochromis spp.), across a range of water hardness. Median effective concentrations (EC50s) in freshwater mussel glochidia ranged from 524 to 904 mg/L NO3-N in moderately hard water. In fish, median lethal concentrations (LC50s) ranged from 228 to 1725 mg/L NO3-N and varied with water hardness. selleck compound Of the species tested, generally sensitivity of the common species was similar to the rare species, although relative sensitivity varied with water hardness. Based on these results, we can conclude that acute lethal effects are unlikely for the fish and mussel species considered here at current environmental levels, but the results of these standardized tests are useful for the development of ambient water quality criteria and other regulatory and management decisions regarding acute nitrate exposures.Use of pesticides continues to be indiscriminate, and birds are one of the worst affected non-targeted organisms. Information on the ill effects of pesticides on birds far from desired in India. Despite the presence of a wide variety and number of birds, there is exceedingly little data on organochlorine pesticide (OCP) residues in colonial nesting birds in sanctuaries of India. A total of 76 individuals belonging to 14 species of birds found dead between March 2008 and March 2010 were analyzed for pesticide residues in various tissues. Of all the OCPs analyzed, concentration of HCH was found to be the highest. Magnitude of contamination varied widely among species. Accumulation pattern of OCPs in colonial nesting birds was in the order ∑HCH > ∑endosulfan > ∑DDT > heptachlor epoxide > dieldrin. Pesticides, namely p,p-DDE and β-HCH contributed most towards the total OCPs. Concentrations of DDT and its metabolites, HCH and isomers, dieldrin, and heptachlor epoxide were lower than the concentrations reported for various species of birds elsewhere in India. Although the sanctuaries presently studied have official boundaries, physical demarcations are missing and there are no proper earthen dykes particularly in Vedanthangal and Koonthankulam Bird Sanctuaries. During monsoon, runoff not only floods the Sanctuaries but also the cultivated areas nearby. Run off brings in residues of pesticides and fertilizers from the agricultural lands into the sanctuaries. Although OCP results in this study were below threshold limits, it may be noted that the long duration exposure even to low levels of pesticides could create a significant impact at population level. Hence, earthen dykes need to be built to avoid agricultural runoff entering the Sanctuary and also help to hold sufficient amount of water for breeding birds.The concentrations, composition, sources, and risks of polycyclic aromatic hydrocarbons (PAHs) in topsoil and surface water of the Liuxi River basin, south China were analyzed in this study. The total concentrations of 16 PAHs ranged from 296.26 to 888.14 ng/g in topsoil and from 156.73 to 422.03 ng/L in surface water, indicating mild pollution. The PAHs in topsoil exhibited an even spatial distribution, suggesting that they originated primarily from dry and wet deposition of transported pollutants. The concentration of PAHs in surface water did not differ significantly geographically, but the concentrations of total, three-, and four-ring PAHs were significantly lower in the Liuxi River than in its tributaries. Three- and two-ring PAHs predominated in topsoil and surface water, respectively. A correlation analysis suggested that the total organic carbon content and pH exerted a negligible effect on the spatial distribution of PAHs in topsoil, and they may have common sources. Fossil fuel combustion (particularly vehicle emissions) and coking production were the dominant sources of PAHs in topsoil, whereas those in surface water were derived from a variety of sources. The total toxic equivalent concentrations of 16 PAHs in topsoil ranged from 3.73 to 105.66 ng/g (mean, 30.93 ng/g), suggesting that exposure to the basin's topsoil does not pose a risk to the environment or public health according to the Canadian soil quality guidelines. A risk assessment revealed that the total PAH concentrations in surface water posed a low ecological risk.PURPOSE To recommend a new simple and explicit index termed the anteroposterior diameter of the lateral ventricle index (ALVI) for assessing brain ventricular size in neuroimaging and to compare Evans index (EI) between idiopathic normal pressure hydrocephalus (iNPH) patients and age-matched healthy elderly subjects. METHODS Retrospective measurements of ventricular volume (VV), relative VV (RVV), the EI, and the ALVI were taken from thin-section CT scans for 23 pre-shunt-insertion iNPH patients and 62 age-matched healthy elderly volunteers. The area under the receiver operating characteristic (ROC) curve (AUC), net reclassification improvement (NRI), and integrated discrimination improvement (IDI) were calculated to assess the effectiveness of ALVI scores for predicting VV. RESULTS The correlations between VV or RVV and ALVI scores (VV, r = 0.957; RVV, r = 0.983) were significantly stronger than the corresponding correlations with EI scores (VV, r = 0.843; RVV, r = 0.840). The AUC for ALVI scores was significantly greater than the AUC for EI scores.

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