Investigation of pesticide residues in water,sediments and fish samples from Tapi River,India as a case study and its forensic significance

Abstract

This research is a case study on detection of pesticides in river water, sediment as well as fish samples from Tapi River, among the major rivers of Gujarat, India. To investigate the misuse, concentration level and occurrence patterns of persistent pesticides, samples were collected from the river. Chlorpyrifos, methyl parathion, hexachlorocyclohexane (HCH), dichloro diphenyl trichloroethane (DDT) and endosulfan were analyzed by gas chromatography technique with flame ionization detector (FID). Scanty reports are available, but after 1999, no such data are reported as some of these pesticides have been banned. Although these pesticides are still in use which we observed from the obtained results. In this river, the amount of endosulfan, chlorpyrifos, and methyl parathion was observed in surface water with concentrations of 37.56?µg/L, 0.86?µg/L and 0.43?µg/L, respectively. Endosulfan, DDT and methyl parathion detected in sediment were 38.38?ng/g, 0.65?ng/g and 0.77?ng/g, respectively. In fish samples, levels of endosulfan, chlorpyrifos, and methyl parathion detected were 101.28, 0.392, and 3.49?ng/g correspondingly. Results showed that highly toxic pesticides are still being used in the surrounding area, and there is an urgent need for enforcement of rules to control the production and application of such pesticides.     

Large-scale utilization of water hyacinth for nutrient removal in Lake Dianchi in China: The effects on the water quality, macrozoobenthos and zooplankton

An ecological engineering project using water hyacinth for nutrient removal was performed in Baishan Bay of a large shallow eutrophic lake, Lake Dianchi in China. In the present study, a systematic survey of water quality, macrozoobenthos and zooplankton inside (IWH), around (AWH) and far away (FWH) water hyacinth mats was conducted in Baishan Bay from August to October 2010. The results showed that the water quality significantly improved at AWH area. Concentrations of nitrogen and phosphorus were lower and transparency was higher at AWH area than those in IWH and FWH areas. Total densities, dominant species densities, and biodiversity indexes of macrozoobenthos and cladocerans as well as copepods did not differ (P > 0.05) among each other in all three areas. It was significantly (P < 0.05) different for those of rotifers at IWH area compared to those in AWH and FWH areas. The results might suggest a tremendous potential for the utilization of water hyacinth in the eutrophic lake like Lake Dianchi for nutrients removal.     

Influence of arbuscular mycorrhizal fungi on the growth and nutrient status of bermudagrass grown in alkaline bauxite processing residue

A nursery experiment was conducted to evaluate the potential role of arbuscular mycorrhizal (AM) fungi in encouraging the vegetation cover on bauxite residue (red mud) sites. An alkali tolerant bermudagrass (Cynodon dactylon) adapted to local conditions were grown in red mud with different amendments with and without AM fungi to assess mycorrhizal effects on plant growth, mineral nutrition, metal uptake and neutralization of bauxite residue. Inoculation of AM fungi significantly increased the plant growth, nutrient uptake and reduced Fe, Al accumulation in plant tissue and also improved the soil physico-chemical and biochemical properties. Gypsum and sludge amended treatments inoculated with AM fungi had maximum biomass, nutrient uptake and reduced accumulation of metals. The neutralization of red mud was significant in presence of AM fungi than control. The experiment provided evidence for the potential use of bermudagrass in combination with AM fungi for ecological restoration of bauxite residue sites.     

北方景观水体中生态浮床的植物筛选与水质净化效果

以千屈菜(Lythrum salicaria L.)、黄菖蒲(Iris pseudacorus L.)、鸢尾(Iris tectorum Maxim.)3种植物为对象,研究了北京市朝阳区景观水体中生态浮床的植物筛选与水质净化效果.结果显示,千屈菜、黄菖蒲、鸢尾均生长迅速,且千屈菜表现最佳;移栽4个月后,3种植物的生物量分别较初始增加了15.9、8.5和13.1倍,达到945.5、489.2和585.0 g/m2.千屈菜对水体氮、磷的吸收去除能力显著(P<0.001)高于黄菖蒲和鸢尾,其总氮、总磷吸收量分别为黄菖蒲的2.2倍和2.3倍,为鸢尾的2.1倍和1.9倍.生态浮床的水质净化效果总体良好,运行60 d后,水体总氮、总磷浓度分别从16.28和0.27 mg/L降低至5.70和0.18 mg/L,二者去除率分别为65.0%和35.0%.研究表明,千屈菜、黄菖蒲、鸢尾在营造景观和净化水质方面协同作用良好,其中千屈菜表现尤为突出,可作为北方地区生态浮床的首选植物.