Anthropogenic organic contaminants in the effluent of a combined sewer overflow: impact on Boston Harbor

Effluent from a large combined sewer overflow (CSO) in Boston and receiving waters near the CSO outfall were sampled during dry and wet weather conditions. Surficial sediments were also collected from the vicinity of the CSO and at nearby sites. The samples were analyzed for a variety of organic constituents including organic carbon and nitrogen, linear alkylbenzenes (LABs), coprostanol and polychlorinated biphenyls (PCBs). As judged by the presence of waste-specific markers (LABs, coprostanol), the CSO effluent contains sewage under both dry and wet weather conditions. When rainfall occurs, the concentration of suspended solids and all organic constituents in the particulate phase increase, ultimately approaching those characteristic of untreated sewage. The concentrations of LABs and PCBs in the effluent are strongly correlated, indicating that PCBs in the CSO are derived from sewage inputs. During heavy rainfall, the vast majority (> 90%) of the hydrophobic organic substances are associated with suspended particulate matter, whereas during dry weather, a significant fraction resides in the operationally defined 'dissolved' phase. Estimates of the mass emission rates of CSO constituents show that > 70% of the suspended particles and > 90% of the particulate organic carbon, hydrocarbons and trace organics are discharged during wet weather. Particles in the receiving water appear to be strongly influenced by the CSO effluent during wet weather. Concentrations of PCBs in surficial sediments near the CSO are correlated with those of coprostanol and the LABs, indicating that these compounds are derived from similar sources. Based on the observed correlations, approximately 60-80% of the sedimentary PCBs originate from sewage. Comparison of sigma LAB/coprostanol ratios of effluent particles, surficial sediments and sewage sludges suggest that the vast majority of the marker compounds and the PCBs in sediments are not from the CSO, but are derived from one of two sewage treatment plants that discharged sludge into the harbor until 1991. The sludge-derived contaminants were probably carried by tidal currents into Dorchester Bay and deposited in shallow, quiescent embayments where sedimentation is favored. These results illustrate the potential importance of long-range transport of waste-derived contaminants in urban harbors and their rapid accumulation in localized depocenters.     

Cadmium detoxification processes in the digestive gland of cephalopods in relation to accumulated cadmium concentrations

The high concentrations of cadmium recorded in the digestive gland of cephalopods from various temperate and subpolar waters suggest that these molluscs have developed efficient cadmium detoxification mechanisms. The subcellular distribution of cadmium in the digestive gland cells was investigated in seven cephalopod species from the Bay of Biscay (France) and the Faroe Islands. In most species, cadmium was mainly found in the cytosolic fraction of the digestive gland cells, reaching up to 86% of the total cadmium for the squid Loligo vulgaris from the Bay of Biscay. But species with the highest total level of cadmium showed a higher percentage of cadmium associated to insoluble compounds. The quantification of metallothioneins (MTs) by the polarographic method was performed in order to evaluate the involvement of these proteins in the detoxification of the high amounts of bioaccumulated cadmium. Metallothionein levels in cephalopods ranged form 742 +/- 270 to 3478 +/- 1572 microg/g wet weight. No relationship could be established between total cadmium, cytosolic cadmium and MT levels suggesting the occurrence of other Cd-binding ligands. Although these proteins have not been characterised, as cadmium in the digestive gland of cephalopods is mainly associated with soluble ligands, a high potential transfer to predators can be predicted.     

Work force of India's scheduled caste population: a spatial perspective

This study was conducted to explore the work force of India's scheduled caste population in a spatial perspective. Findings are based upon data from detailed district-wise maps from data relating to the workers. Peninsular India has a far larger proportion of workers to the total scheduled caste population than northern India. The degree of participation of females trying to earn their living is the most crucial factor in the broad regional differentiation which is then associated with women's social status and autonomy in the society and their freedom from inhibitions to work outside of the home. These factors are deeply rooted in the histories of the two regions and their components. Demographic, economic, and political variables are intermingled with the social and cultural dimensions to impact upon the magnitude and composition of the work force. Further disparities exist within and across macro-regions at meso and micro regional levels which are connected with socioeconomic and demographic specificities of the local/regional situations.     

Response of estuarine meio- and macrofauna to in situ bioremediation of oil-contaminated sediment

Numerous studies have demonstrated the efficacy of bioremediation for enhancing oil removal but the ecological effect on shoreline biota is unclear. Therefore, a field experiment was designed at an intertidal sandflat in SW England to assess the effects of nutrient addition to oiled sediments on meio- and macrofauna for a period of up to 45 weeks. Natural assemblages were exposed to different types of experimental treatments (no oil, oil alone, oil treated with slow-release fertiliser or liquid fertiliser). Bioremediation stimulated the microbial population and increased oil biodegradation. This, however, did not result in faster recolonisation rates of fertilised versus non-fertilised oiled sediments. Mild effects of oil and bioremediation treatments on benthic fauna were observed, including short-term shifts in dominance patterns. Decreased abundance of dominant species in the oiled compared to unoiled sediments resulted in significantly higher evenness of benthic assemblages within the first 11 weeks of the experiment.     

杰安特·耶洛奈夫金矿的储量计算和品位控制

到1966年底为止,(加拿大大奴湖滨的)杰安特·耶洛奈夫金矿已生产了大约540万吨矿石,平均品位0.75盎斯/吨.选厂从1948年夏开始生产时,日处理量为250吨,到1958年已增加到800吨.1959年以来,每日的采选矿石量已略高于1000吨.现在的储量(包括附近的各矿山)估计为250万吨,平均品位0.67盎斯/吨.绿泥石和绢云母带中不规则的、透镜状的和脉状的矿体的规模、形态和产状都是极其多变的(图1).采场的长度可由50英尺到400英尺,宽度由10英尺以下到100英尺以上.片岩带横切一组向西陡倾的火山岩.虽然片岩带的叶理是陡倾或直立的,但它的各组岩相可能向东西方向作较缓或较陡的倾斜.总的看来,这一岩带是一个有倾伏背斜和向斜的折皱了的地层单元.