水污染的生物自动监测

生物监测是指有规则地或连续地评价一个或多个参数,而且可以用来测定有害状态。通过对生物监测领域发展状况的描述,建议水污染质量控制系统要把生物和化学-物理信息结合起来,并根据生物监测的数据进行修正,利用水生生物来及早地警报水体中存在有毒物质,并与电子计算机设备相结合,形成早期警报毒性监测系统,提出了发展生物自动监测系统的可行性,指出它在水污染控制中将成为必要的工具。     

运用热带爪蟾胚胎测定工业废水的发育毒性

采用热带爪蟾胚胎测定江苏省常州市8家典型行业工业废水的发育毒性,结果显示：各行业工业废水对爪蟾胚胎的发育均有不同程度的影响,而印染、啤酒、电镀和化工行业出水的发育毒性更强。试验表明,理化指标并不能完全反映工业废水的综合毒性,而热带爪蟾胚胎可有效地表征其发育毒性。比较各行业工业废水的毒性,初步探讨热带爪蟾胚胎用于工业废水毒性检测的可行性。     

Perspectives of the chemical fate and toxicity of pesticides

Abstract

The wide‐spread use of pesticides in modern agriculture has created a need to investigate the chemical transformation of pesticides in plants and animals. This paper reviews the chemical and biochemical fate of various pesticides and other xenobiotics. Photochemical mechanisms appear to be the most common pathways for the abiotic transformation of these chemicals. Biotic transformation includes a large group of biochemical reactions which may result in either deactivation (detoxication) or activation (toxication) of bioactive compounds. The need for quality control in the production of pesticides is also discussed.     

Toxicity and metabolism of acephate in adult and larval insects

Abstract

Adult and larval insects from the terrestrial and aquatic environments were exposed to acephate. The chemical was more toxic to adult insects than to larvae, and was a poor insect cholinesterase inhibitor in vitro compared to methamidophos which was a much stronger inhibitor. Both acephate and methamidophos inhibited the adult cholinesterase in vitro much more strongly than they did the larval enzymes. Acephate was metabolized by the insects to methamidophos which did not appear to be the only metabolite, although no other metabolites were looked for. The cholinesterase of insects exposed to sublethal levels of acephate was inhibited, but this inhibition appeared to be due to the combined effect of acephate and methamidophos and not to any hypothetical substance with greater anticholinesterase activity. This was bourne out when acephate was incubated with mixed function oxidases (MFO). No activated product with potent anticholinesterase activity was identified. Methamidophos was not produced by the MFO system but by some other unidentified mechanism.     

A Protocol to Select High Quality Datasets of Ecotoxicity Values for Pesticides

Abstract

The key to any QSAR model is the underlying dataset. In order to construct a reliable dataset to develop a QSAR model for pesticide toxicity, we have derived a protocol to critically evaluate the quality of the underlying data. In developing an appropriate protocol that would enable data to be selected in constructing a QSAR, we concentrated on one toxicity end point, the 96 h LC50 from the acute rainbow trout study. This end point is key in pesticide regulation carried out under 91/414/EEC. The dataset used for this exercise was from the US EPA-OPP database.     

Survival and behavior of the insecticide-exposed predators Podisus nigrispinus and Supputius cincticeps (Heteroptera: Pentatomidae)

Pentatomid stinkbugs are important predators of defoliating caterpillars in agricultural and forestry systems, and knowledge of the impact of insecticides on natural enemies is important information for integrated pest management (IPM) programs. Thus, we assessed the toxicity and behavioral sublethal response of the predators Podisus nigrispinus and Supputius cincticeps exposed to deltamethrin, methamidophos, spinosad and chlorantraniliprole, insecticides commonly used to control the velvetbean caterpillar (Anticarsia gemmatalis) in soybean crops. With the exception of deltamethrin for S. cincticeps, all insecticides showed higher acute toxicity to the prey than to these natural enemies providing effective control of A. gemmatalis. The recommended field concentration of deltamethrin, methamidophos and spinosad for controlling A. gemmatalis caused 100% mortality of P. nigrispinus and S. cincticeps nymphs. Chlorantraniliprole was the less toxic and the most selective insecticide to these predators resulting in mortalities of less than 10% when exposed to 10× the recommended field concentration for a period of 72 h. Behavioral pattern changes in predators were found for all insecticides, especially methamidophos and spinosad, which exhibited irritability (i.e., avoidance after contact) to both predator species. However, insecticide repellence (i.e., avoidance without contact) was not observed in any of the insects tested. The lethal and sublethal effects of pesticides on natural enemies is of great importance for IPM, and our results indicate that substitution of pyrethroid and organophosphate insecticides at their field rates by chlorantraniliprole may be a key factor for the success of IPM programs of A. gemmatalis in soybeans.     

Bioadsorption and bioaccumulation of chromium trivalent in Cr(III)-tolerant microalgae: A mechanisms for chromium resistance

Anthropogenic activity constantly releases heavy metals into the environment. The heavy metal chromium has a wide industrial use and exists in two stable oxidation states: trivalent and hexavalent. While hexavalent chromium uptake in plant cells has been reported that an active process by carrying essential anions, the cation Cr(III) appears to be taken up inactively. Dictyosphaerium chlorelloides (Dc1M), an unicellular green alga is a well-studied cell biological model organism. The present study was carried out to investigate the toxic effect of chromium exposures on wild-type Cr(III)-sensitive (Dc1M^wt) and Cr(III)-tolerant (Dc1M^Cr(III)R30) strains of these green algae, and to determine the potential mechanism of chromium resistance. Using cell growth as endpoint to determine Cr(III)-sensitivity, the IC₅₀₍₇₂₎ values obtained show significant differences of sensitivity between wild type and Cr(III)-tolerant cells. Scanning electron microscopy (SEM) showed significant morphological differences between both strains, such as decrease in cell size or reducing the coefficient of form; and transmission electron microscopy (TEM) revealed ultrastructural changes such as increased vacuolization and cell wall thickening in the Cr(III)-tolerant strain with respect to the wild-type strain. Energy dispersive X-ray analysis (SEM/XEDS) revealed that Cr(III)-tolerant D. chlorelloides cells are able to accumulate considerable amounts of chromium distributed in cell wall (bioadsorption) as well as in cytoplasm, vacuoles, and chloroplast (bio-accumulation). Morphological changes of Cr(III)-tolerant D. chlorelloides cells and the presence of these electron-dense bodies in their cell structures can be understood as a Cr(III) detoxification mechanism.     

Toxic effects of imidazolium-based ionic liquids on Caenorhabditis elegans: The role of reactive oxygen species

By using Caenorhabditis elegans (C. elegans) as a model animal, the present work is aimed to evaluate the acute toxicity of imidazolium-based bromide Ionic Liquids (ILs), and to elucidate the underlying mechanisms involved. Firstly, 24-h median lethal concentration (LC₅₀) for eight ILs with different alkyl chain lengths and one or two methyl groups in the imidazolium ring were determined to be in a range of 0.09–6.64 mg mL⁻¹. Four ILs were selected to investigate the toxic mechanisms. Mortality, levels of reactive oxygen species (ROS), lipofuscin accumulation and expression of superoxide dismutase 3 in C. elegans were determined after exposed to ILs at sub-lethal concentrations for 12 h. A significant increase in the levels of these biomarkers was observed in accordance with the results of 12-h lethality assay. The addition of 0.5% dimethyl sulfoxide, which acts as a radical scavenger, remarkably rescued the lethality of C. elegans and significantly decreased the ROS level in C. elegans. Our results suggest that ROS play an important role in IL-induced toxicity in C. elegans.     

摇蚊幼虫的水生态毒理学研究进展

本文综述了国外对摇蚊幼虫的水生态毒理学研究的最新进展，包括生物检测、生物积累和遗传毒理研究等几方面．国外的研究表明摇蚊幼虫可以作为常用试验生物（鱼类和蚤类）的补充，用于有毒化学品的急、慢性毒性生物检测和遗传毒性研究，以及生物积累试验，以评价化学品的生态效应，并对污染物进行生物监测．     

我国水质基准现状及发展趋势研究

水质基准是制定水质标准限值的重要依据,是科学的水质管理体系的重要组成部分。我国水体污染形势严峻,区域环境差异明显,亟需建立适合我国水环境特征的水质基准作为水质控制和管理的理论依据。文章对我国水质基准的概况、水质基准方法学、水质基准研究进展、存在问题及发展趋势进行了系统论述,以期为我国水质基准的研究提供参考与支撑。