Ecological Risk Assessment of Neem-Based Pesticides

Abstract

A tiered process was used to evaluate the risks of pure azadirachtin (AZA) and two neem-based insecticides (Neemix? and Bioneem?) on six aquatic animals [crayfish (Procambarus clarkii), white shrimp (Penaeus setiferus), grass shrimp (Palaemonetes pugio), blue crabs (Callinectes sapidus), water fleas (Daphnia pulex), and mosquito larvae (Culex quinquefasciatus)] through short term acute toxicity tests. The risk was calculated using the level of concern endpoints (Q values) and relative hazard index (RHI) for acute and chronic exposure scenarios. The Q values of Neemix?, Bioneem?, and pure AZA derived from acute exposure tests indicated that D. pulex is the only sensitive species to the test pesticides. Furthermore, the RHI values of Neemix? and Bioneem? for D. pulex were above the critical limit of 10 indicating that these pesticides may pose a moderate hazard to this species and related crustaceans in acute exposure scenarios. The RHI values of the two pesticides and pure AZA were all below the critical limit of 10 for P. clarkii, P. setiferus, P. pugio, C. sapidus, and C. quinquefasciatus. The aquatic risk assessment process showed that the risk values of tested pesticides did not exceed the criteria, and therefore, no ecological hazard is likely to result from their use.     

基于层次分析法的人工湿地减排绩效评估指标体系研究

绩效减排有助于发挥减排工程潜力,为水污染减排提供更大空间.结合人工湿地特点,以水污染物减排为主要目标,从减排治污、资源利用、经济和管理指标选择了12个评估指标,并基于层次分析法对各个评价因子的权重进行了确定和判断,构建了人工湿地减排绩效评估指标体系,评估人工湿地减排绩效.通过科学分析人工湿地的减排绩效,优化人工湿地规划、设计和管理水平.     

基于熵值法新疆循环经济发展综合评价分析

根据循环经济理论,针对新疆循环经济的发展,从资源可承载能力、环境发展、社会经济发展三个方面考虑建立新疆循环经济发展的综合评价指标体系,运用熵值法对新疆10年循环经济的发展水平进行综合评价,进而提出了相应的措施,包括完善法律法规体系、加快产业结构调整、加大政策鼓励力度、促进产业集聚等.     

Effects of bulking agent addition on odorous compounds emissions during composting of OFMSW

The effects of rice straw addition level on odorous compounds emissions in a pilot-scale organic fraction of municipal solid waste (OFMSW) composting plant were investigated. The cumulative odorous compounds emissions occurred in a descending order of 40.22, 28.71 and 27.83 mg/dry kg of OFMSW for piles with rice straw addition level at ratio of 1:10, 2:10 and 3:10 (mixing ratio of rice straw to OFMSW on a wet basis), respectively. The mixing ratio of rice straw to OFMSW had a statistically significant effect on the reduction of malodorous sulfur compounds emissions, which had no statistically significant effect on the reduction of VFAs, alcohols, aldehydes, ketones, aromatics and ammonia emissions during composting, respectively. The cumulative emissions of malodorous sulfur compounds from piles with the increasing rice straw addition level were 1.17, 1.08 and 0.88 mg/dry kg of OFMSW, respectively. The optimal mixing ratio of rice straw to OFMSW was 1:5. Using this addition level, the cumulative malodorous sulfur compounds emissions based on the organic matter degradation were the lowest during composting of OFMSW.     

Growth and Histopathological Effects of Chronic Exposition of Marine Pejerrey Odontesthes argentinensis Larvae to Petroleum Water-Soluble Fraction (WSF)

The water-soluble fraction (WSF) of petroleum contains a mixture of polycyclic aromatic hydrocarbons, volatile hydrocarbons, phenols, and heterocyclic compounds, considered deleterious to aquatic biota. Marine “pejerrey” Odontesthes argentinensis (Teleostei: Atherinopsidae) has a great commercial importance in local fisheries and a high potential for aquaculture. The aim of this study was to evaluate the histopathological effects in “pejerrey” larvae exposed to different concentrations of petroleum WSF. The chronic toxicity test was conducted with newly hatched larvae exposed for 21 days to sublethal concentrations of WSF (2.5, 5, 10, and 20 % of WSF), plus one control. Survival and growth were significantly lower in the highest concentration. Several histopathological changes were found in the gills (e.g., hyperplasia, aneurisms, edema, and necrosis), kidney (e.g., nuclear alterations, decrease in the hematopoietic cells), and liver (e.g., hypertrophy, karyorrhexis, and karyopyknosis). An index of branchial lesion was proposed to standardize gill lesions to different pollutants.     

南苕溪支流锦溪水质时空变化特征分析

综合运用灰色聚类法、综合污染指数法、等级聚类法就南苕溪支流锦溪近年水质时空变化特征进行分析。结果表明,锦溪入青山水库断面水质2005—2009年逐年改善,2007年后达到灰色聚类等级Ⅲ类水质要求;2009年秋季至2010年夏季期间秋、冬两季的污染程度高于春、夏季节;枯水期综合污染指数最高,但TN、TP污染分指数在丰水期最高,表明污染源中面源污染已占相当比例。空间变化方面从玲珑桥到江桥锦溪水质的综合污染指数不断提升,到江桥时达到极值13.25,锦溪末端三眼桥断面水质较江桥断面有所改善;SPSS空间聚类分析可分为轻污染区(从玲珑桥到冬韵桥)、重污染区(从群利桥到江桥)和中度污染区(从江桥到三眼桥)。锦溪上游农业区对河水中的COD、TN和TP的贡献率分别为66%、54%和49%,农业面源污染已成为制约锦溪水质改善的主要因素。     

神经网络模型在北海市空气日报污染指数计算中的应用

根据空气质量日报的实际需要,引入了Excel软件神经网络技术建立空气质量日报污染指数计算模型,采用LM算法提高了计算精度,并将模型应用于北海市空气日报。结果表明:此法较之实际公式计算法更加快捷方便,并且计算结果相当吻合。     

中国水利现代化进程的评价和展望

着眼于中国现代化建设的历史全局,从安全性需求保障度、经济性需求保障度、舒适性需求保障度以及水生态环境和谐度四个维度,构建了中国水利现代化评价指标体系。通过定量评价,本文测算了中国未来5年、10年、20年和40年的水利现代化实现程度。从评价结果来看,2000年,中国水利现代化综合实现程度为30%;2010年,水利现代化综合实现程度提高到46%,表明过去十年是水利现代化的快速提升期。预计到2015年,中国水利现代化实现程度将提高到56%;到2020年,水利现代化综合实现程度将提高到70%,总体上达到中等现代化的水平;到2030年,水利现代化综合实现程度达到91%,基本实现水利现代化,水利发展水平与经济高收入水平基本相适应。展望2030年以后,中国水利发展将进入水生态环境全面修复和保护的时期;至2050年,中国将实现人水和谐、山川秀美,全面建成绿色现代化。由于国家对水利工作的高度重视,可以预见,中国未来十几年的水利现代化进程会大大加快,有可能在2030年或更早时间基本实现水利现代化。     

安徽经济发展对资源环境的压力分析

目前,安徽省经济已经进入新一轮增长周期的上升阶段,经济发展正面临着重大转折.在快速发展的同时,也面临着诸多挑战,尤其是资源、环境方面的约束进一步加剧.因此,定量研究安徽省目前经济发展所面临的资源环境压力及其产生原因具有一定的现实意义.本文在充分吸收前人研究成果基础上,通过运用经济增长与资源环境压力指数法定量分析安徽省经济发展过程中所面临的资源环境压力,得出1999 -2008年间,安徽省资源环境压力一直偏大,且有不断恶化的趋势.在此基础上,进一步分析了造成安徽资源环境压力偏大的原因——产业结构偏重、环保投入不足等,并提出相关对策建议.     

农村最低生活保障政策在实施过程中的瞄准分析

随着我国扶贫战略从区域扶贫向个人扶贫的转变,2007年我国在农村地区全面建立了最低生活保障制度.基于一份具有全国代表性的农户资料,本文采用赤贫指数从多维度度量了农户的贫困程度,并将其应用于农村最低生活保障制度的瞄准效率研究.赤贫指数越低,表示农户越贫困,理论上,这些农户也越应该获得领取最低生活保障资格.结果发现,现阶段我国农村最低生活保障制度瞄准效率不高,瞄准遗漏和瞄准漏出同时存在.其中,在村级层面的分析结果发现,样本村中只有25.5%的最贫困农户在2007年得到了低保;同时,处于赤贫指数最低端的20%和40%的农户分别只得到了最低生活保障名额的50.67%和73.33%.而在获得最低生活保障的农户中,有1/5以上的农户认为低保金对改善他们家庭经济状况帮助很小或者没有任何帮助.基于以上研究结论,本文认为政府在继续增加对农村最低生活保障制度的财政投入的同时,应当在建立健全更为规范完善的收入核算标准的基础上,从研究和实践两个方面继续探索发展适合我国农村的多维度的贫困户鉴别制度,提高农村低保的瞄准效率.