镉对稻田土壤典型微生物种的胁迫生理毒性

以水稻田土壤中典型的单种微生物为实验材料,采用纯培养方法,从个体水平上全面探讨了重金属镉胁迫对稻田土壤典型微生物的的生长、活性以及生化过程的生理毒性影响。研究表明:不同微生物纯培养对镉胁迫的敏感程度不同,G 较G-对Cd2 更为敏感,表现为世代时间缩短,最高菌浓度下降。固氮菌对Cd2 非常敏感,当Cd2 质量浓度为0.2mg·L-1时即完全抑制菌体增殖。同时,外源镉强烈的抑制作为稻田土壤中功能微生物的厌氧固氮菌及产甲烷细菌的生物活性,各菌种镉胁迫下细菌细胞内可溶性蛋白、还原糖、核酸质量浓度都在低质量浓度镉胁迫时有所增加;随着镉质量浓度的增加,细菌细胞内各种物质的质量浓度开始减小,以减慢细胞代谢速度,增强对镉胁迫的适应力;各种物质的质量浓度变化趋势为可溶性蛋白>还原糖>核酸,R.eutrophaDKC1细胞内含物质量浓度基本保持稳定。结果可在一定程度上说明镉对微生物的毒性效应,且能在早期较灵敏地指示污染的影响,作为稻田土壤环境受到污染胁迫的细胞生化指标具有一定可行性。     

对化学品登记要求的数据解释——急性毒性和急性刺激

本文对化学品登记时所要求的部分健康效应数据一急性毒性和急性刺激做了解释.涉及到的测试参数包括:急性经口毒性、急性经皮毒性、急性吸入毒性、急性皮肤刺激/腐蚀和急性眼睛刺激/腐蚀.     

应用BLM模型预测我国主要河流中Cu的生物毒性

应用BLM模型对我国5条主要河流15个国控断面中铜的生物毒性进行预测,同时以虹鳟鱼为实验动物进行了实际水样的加标实验,得到实测生物毒性结果.结果表明,珠江、长江、淮河、松花江12个点位BLM模型预测LC50为0.13～0.46mg·L-1,利用虹鳟鱼进行的生物毒性测试结果为0.11～0.47mg·L-1,二者具有较好的一致性.对于黄河流域的3个点位,预测结果为0.42～1.00mg·L-1,实测结果为0.21～0.33mg·L-1,二者差距较大.根据预测结果与测试结果得到的水效应比(WER)范围分别为3.3～11.8与3.3～11.5(黄河流域,WERs值范围分别为10.5～25.0与5.3～8.3),均大于1.该研究提示,中国主要河流水系由于水化学条件不同,即使在相同的总Cu浓度下,所表现的毒性亦有很大差别;利用BLM模型和河流主要水质参数,则可以预测Cu的毒性.根据BLM模型获得的Cu的WERs值,将是制订中国流域水质标准的重要依据.     

Rapid ecotoxicological assessment of heavy metal combined polluted soil using canonical analysis

IntroductionElevatedconcentrationofheavymetalssuchascopperandcadmiumexistinmanyagriculturalsoilsfromminingactivities(Chen ,2 0 0 0 ;Dudka ,1 997;Lambert,1 997)andfrommanagementpracticesincludingirrigationwithsewageandutilizationofsewagesludge(Clapp ,1 994) .Onceheavymetalsenteredintosoils,regardlessthesources,theywouldnotonlybeaccumulatedbyorganisms,butalsocirculateinthefoodchain (Uhlig ,2 0 0 0 ;Barcan ,1 998) .Furthermore ,theirramificationwouldberetainedinsoilecosystemwithtoxicconcentrati…     

大亚湾核电站余氯排放对邻近海域环境的影响

对大亚湾核电站冷却水排放口及邻近海域海水中余氯污染状况进行了调查，结果表明：余氯的含量为〈０．０１～０．０４ｍｇ．Ｌ＾－１，各季节平均水平为０．０１～０．０２ｍｇ．Ｌ＾－１，冬季较高。余氯在海水中的形态为化合态。选择若干养殖经济动物进行了余氯毒性胁迫试验。以０．５为安全因子，余氯胁迫作用时间不超过３０ｍｉｎ时，游离斜 氯对平鲷、黑鲷仔鱼的安全容许浓度约为０．１０ｍｇ．Ｌ＾－１，对斑节对虾幼苗为０．     

Ecotoxicological and chemical evaluation of phenolic compounds in industrial effluents

The aim of this paper was to evaluate the ecotoxicological response of industrial effluents containing phenolic compounds. All complex effluents collected from a chemical plant and then after both a chemical–physical and biological treatment were characterised with chemical analysis, biodegradability tests and four ecotoxicological tests (Daphnia magna, Artemia salina, Brachionus plicatilis and Vibrio fisheri with Microtox^®). The evaluation of the chemical and ecotoxicological data was useful for predicting the effect of the raw effluent on the treatment plant and the impact of the final treated effluent on the receiving water. Besides the toxicity of the effluent from the chemical plants, the acute toxicity of its main components was also determined. The results of the tests and toxicity data from literature were transformed in Toxic Units (TUs). Effluent toxicity was under- or over-estimated by calculating the sum of the TUs of the individual components, depending on which toxicity data and test organisms were used.     

A comparative study of the toxicity of 1,1,2-trichloroethane,dieldrin, pentachlorophenol and 3,4 dichloroaniline for marine and fresh water organisms

The aquatic toxicity of 1,1,2-trichloroethane, dieldrin, pentachlorophenol and 3,4-dichloroaniline was determined for about 15 marine and fresh water animals and several unicellular algae. Acute, subchronic and chronic tests including reproduction studies, were carried out. The results are summarized in five tables.     

Comparing aquatic risk assessment methods for the photosynthesis-inhibiting herbicides metribuzin and metamitron

Three different risk assessment procedures are described that aim to protect freshwater habitats from risks of the photosynthesis-inhibiting herbicides metribuzin and metamitron. These procedures are (1) the first-tier approach, based on standard toxicity tests and the application of an assessment factor, (2) the Species Sensitivity Distribution (SSD) approach, based on laboratory tests with a wider array of species and the application of a statistical model to calculate the HCx (the Hazardous Concentration for x% of the species), and (3) the model ecosystem approach, based on the evaluation of treatment-related effects in field enclosures. A comparison of the risk assessment procedures reveals that the first-tier approach is the most conservative for metamitron and metribuzin, and that HC5 values (and even HC10 values) based on acute EC50 values of algae and aquatic vascular plants may be used to derive maximum permissible concentrations for single applications. For both compounds these HC5 values were very similar to the ecological threshold concentrations in the enclosure studies. In contrast to model ecosystem experiments, however, HCx values based on lab toxicity tests do not provide information on the recovery potential of sensitive endpoints and on indirect effects, which may be important for regulatory decision-making. In the enclosure study, indirect effects of metribuzin on invertebrate populations were observed at an exposure concentration that was approximately 20 times lower than the corresponding HC5 value based on lab toxicity data for aquatic invertebrates.     

污染土壤毒性研究方法进展

综述了国内外有关污染土壤毒性研究方法 ,包括传统的方法如植物法、动物法和微生物法等和生态毒理学方法 ,并从生物、非生物和环境等方面论述了影响土壤毒性的因素 ,提出了当前土壤污染毒性研究方法中存在的问题 ,认为随着环境科学技术的发展 ,污染土壤毒性研究方法在环境保护中必将发挥越来越重要的作用     

微生物抗重金属毒性研究进展

不少重金属是微生物正常生长的必需元素 ,但是当重金属在菌体内浓度过高时 ,会对菌体产生毒性。微生物可通过细胞的表面富集与细胞膜成分的改变减小毒性的破坏 ,在重金属进一步的诱导下 ,菌体会产生由结构基因与调节基因组成的抗性基因 ,通过多途径的联合作用对重金属的毒性进行解毒