Multiple residues of organochlorine insecticides were monitored in Ganga river water in the district of Farrukhabad in northern Indian for one year (1991–1992). Almost all the samples were found to be contaminated with residues of HCH and DDT. Residues of aldrin, endosulfan and heptachlor were also detected in a larger number of samples. Alpha-HCH, pp-DDT and alpha-endosulfan were found to dominate over the other isomers of HCH, DDT and endosulfan, respectively. Enhanced percentage of beta-HCH suggests accumulation of this isomer in the aquatic environment. The average concentration of aldrin was more than that of dieldrin. Aldrin residues often exceeded the WHO guideline value for drinking water and the concentration of heptachlor occasionally exceeded the specified limits. 相似文献
Environmental Chemistry Letters - Diminishing petroleum reserves, increasing carbon emissions, and the growing demand for fuels are calling for alternative fuels. Global diesel consumption... 相似文献
Biofuels extracted from plant biomass can be used as fuel in CI engines to lower a hazardous atmospheric pollutant and mitigate climate risks. Furthermore, its implementation is hampered by inevitable obstacles such as feedstocks and the crop area required for their cultivation, leading to a lack of agricultural land for the expansion of food yields. Despite this, microalgae have been discovered to be the most competent and unwavering source of biodiesel due to their distinguishing characteristics of being non-eatable and requiring no cropland for cultivation. The objectives of this paper was to look into the potential of a novel, formerly underappreciated biodiesel from microalgae species which could be used as a fuel substitute. Transesterification is being used to extract the biodiesel. Microalgae are blended with petroleum diesel in percentage to create microalgae blends (MAB) as needed for experimentation. The impact of biodiesel on performance as well as exhaust emission attributes of a 1-cylinder diesel engine was experimentally studied. Compared to petroleum diesel, different blend of microalgae biodiesel showed a decline in torque and hence brake power, resulting in an average fall of 7.14 % in brake thermal efficiency and 11.54 % increase in brake-specific fuel consumption. There were wide differences in exhaust emission characteristics, including carbon monoxide and hydrocarbon, as the blend ratio in diesel increased. Moreover, nitrogen oxides and carbon dioxides increase in all algae biodiesel blends, but they are still within the acceptable range of petroleum diesel.
In an effort to determine vehicular impact on soil quality, soil samples were collected from three different zones (Pahalgam, Batakote, and Chandanwari) in Pahalgam forest ecosystem. Results showed that a significant decrease in moisture content, organic carbon, available nitrogen, and potassium was observed in nearby road side soils. However, pH was observed to be on neutral side and available phosphorus recorded high concentration. The concentration of heavy metals Pb2+, Cu2+, Zn2+, Ni2+, and Cd2+ estimated was also significantly high. Furthermore, concentration of Pb2+ at high vehicular load subzones was observed to be highest (1.168 mg/Kg) followed by Zn2+ (0.896 mg/Kg), Ni2+ (0.649 mg/Kg), Cu2+ (0.415 mg/Kg), and Cd2+ (0.079 mg/Kg). An inter-zone analysis revealed that the concentration of the heavy metals (Pb2+?>?Ni2+?>?Cd2+) was observed to follow the trend, Z-I?>?Z-II?>?Z-III. Variation along the temporal gradient and the impact on soil qualities were notably higher in summer. Vehicular pollution to a great extent impacts physico-chemical characteristics and more interestingly adds substantial concentration of heavy metals in soils. 相似文献
Rising global population would force farmers to amplify food production substantially in upcoming 3–4 decades. The easiest way to increase grain production is through expanding cropping area by clearing uncultivated land. This is attained by permitting deadly loss of carbon (C) stocks, jeopardizing ecosystem biodiversity and deteriorating environmental quality. We aim to propose key agronomical tactics, livestock management strategy and advance approaches for aquaculture to increase productivity and simultaneously reduce the environmental impacts of farming sector. For this, we considered three major sectors of farming, i.e. agriculture, fishery and dairy. We collected literatures stating approaches or technologies that could reduce GHG emission from these sectors. Thereafter, we synthesized strategies or options that are more feasible and accessible for inclusion in farm sector to reduce GHG emission. Having comprehensively reviewed several publications, we propose potential strategies to reduce GHG emission. Agronomic practices like crop diversification, reducing summer fallow, soil organic carbon sequestration, tillage and crop residue management and inclusion of N2-fixing pulses in crop rotations are some of those. Livestock management through changing animals’ diets, optimal use of the gas produced from manures, frequent and complete manure removal from animal housing and aquaculture management strategies to improve fish health and improve feed conversion efficiency could reduce their GHG emission footprint too. Adapting of effective and economic practices GHG emission footprint reduction potential of farming sector could make farming sector a C neutral enterprise. To overcome the ecological, technological and institutional barriers, policy on trade, tax, grazing practice and GHG pricing should be implemented properly. 相似文献
A multitrophic outdoor mesocosm system was used to mimic a wetland ecosystem and to investigate the effects of glyphosate and two herbicide mixtures on wetland microbial communities. The glyphosate concentration used was 1000 times the environmentally relevant concentration (ERC). One herbicide mixture consisted of six auxin-type herbicides (2,4-D, MCPA, clopyralid, dicamba, dichlorprop, mecoprop), each at 1000 times the ERC. The second mixture was comprised of eight herbicides, including the six auxin-type herbicides as well as bromoxynil and glyphosate. For this mixture, a dose-response approach was used to treat mesocosms with the ERCs of each herbicide as the base concentration. Algal biomass and production and bacterial production and numbers for pelagic and attached communities were measured at different times over a 22-d period. The experimental results indicate that the eight-herbicide mixture, even at low concentrations, produced negative effects on microbial communities. Glyphosate on its own suppressed algal biomass and production for the duration of the study in pelagic and biofilm communities. Algal biomass and production, although initially depressed in the auxin-type herbicide treatment, were stimulated from Day 9 until experiment end. Due to their similar modes of action, the effects of this herbicide mixture appear to be a result of concentration addition. Such negative effects, however, were brief, and microbial communities recovered from herbicide exposure. Based on evidence presented in this study, it appears that glyphosate has a higher potential to inhibit primary production and chlorophyll content in pelagic and attached wetland algal communities than the auxin-type herbicide mixture. 相似文献
In this study, changes in heavy metal accumulation in U. rigida J. Agardh taxon and seawater have been investigated with respect to different stations and seasons. For this purpose, the severity of heavy metal pollution in the Dardanelles has been presented through the determination of Cu, Pb, Zn, and Cd concentrations in U. rigida macroalgae and seawater taken seasonally from the stations located on six different regions on the strait. While the metal concentrations in alga specimens were found to be high in spring and winter in all stations; the metal concentrations in the seawater, particularly the Pb concentration, were found to be high in all seasons. 相似文献
Puri City is situated on the east coast of India and receives water supply only from the groundwater sources demarcated as water fields. The objective of this paper is to assess and evaluate the groundwater quality due to impact of anthropogenic activities in the city. Groundwater samples were collected from the water fields, hand pumps, open wells, and open water bodies during post-monsoon 2006 and summer 2007. Groundwater quality was evaluated with drinking water standards as prescribed by Bureau of Indian Standards and Environmental Protection Agency to assess the suitability. The study indicated seasonal variation of water-quality parameters within the water fields and city area. Groundwater in the water fields was found to be suitable for drinking after disinfection. While in city area, groundwater quality was impacted by onsite sanitary conditions. The study revealed that groundwater quality was deteriorated due to the discharge of effluent from septic tanks, soak pits, pit latrines, discharges of domestic wastewater in leaky drains, and leachate from solid waste dumpsite. Based on observed groundwater quality, various mitigation measures were suggested to protect the water fields and further groundwater contamination in the city. 相似文献