Landfill Leachate Ecotoxicity Experiments using Lemna minor

The effects of varying concentrations of landfill leachate on the growth, frond area, chlorophyll content and fluorescence of four strains of Lemna minor were assessed. Growth fluorescence and frond chlorophyll content decreased after seven days exposure to leachate, although responses differed between the strains and end parameters. A L. minor bioassay was used to assess leachate toxicity and the effectiveness of a constructed wetland treatment system and pre-treatment aeration and settlement in reducing toxicity. Pre-treatments were found to significantly reduce toxicity, so their incorporation in any treatment system may increase pollutant stripping.     

石油污染土壤微生物修复过程中植物毒性变化规律

植物幼苗生长发育和叶片的生化指标能综合反映土壤石油污染的程度及其生态毒性的强弱.为探究植物对石油污染土壤生态毒性的指示效果和污染土壤在生物修复过程中毒性的变化规律,本研究采用3株对石油烃具有良好降解效果的降解菌构建混合菌体系,开展石油污染土壤模拟微生物修复实验.文章考察了5种典型植物指示不同修复时期土壤生态毒性强弱的可行性与敏感性,并进一步从生态学角度揭示修复过程中石油污染土壤生态毒性的变化规律.结果表明,小麦和萝卜相对于莴苣、黑麦草和小青菜而言,更适宜作为石油污染土壤的指示生物.石油污染土壤的生态毒性随着微生物修复过程的进行呈先上升后下降的趋势,石油污染土壤生态毒性在修复的第8 d达到最大.不同的供试植物对石油污染的响应存在一定的差异.小麦和萝卜的生长发育指标能较为敏感地指示石油污染土壤在微生物修复过程中的生态毒性,可作为石油污染土壤微生物修复效果的指示生物.     

Biodegradation and ecotoxicological assessment of pectin production wastewater

The chemical composition of pectin production wastewater and its toxicity during biological treatment were investigated. Samples of wastewater from di erent steps of a pectin production wastewater biological treatment plant were investigated including the influent of the treatment (1), after denitrification tank (2), after anaerobic treatment (3) and final e uent (4). The conventional physicochemical characteristics of samples did not indicate wastewater toxicity. However, toxicity assessments carried out on Vibrio fischeri and Scenedesmus subspicatus indicated low EC50 values. The fractionation of the samples using an XAD resin showed that the toxicity was associated with the organic matter. Wastewater apparent molecular mass distributions were 14.3, 25.0, 24.4 and 29.6 kDa for samples 1–4, respectively. Finally, characteristics of the sample by pyrolisis-gas chromatography-mass spectrometry (Py-CG-MS) demonstrated its polyphenolic nature and a 23% increase in the levels of such compounds after the first biological treatment step.     

A multi-integrated approach on toxicity effects of engineered TiO2 nanoparticles

The new properties of engineered nanoparticles drive the need for new knowledge on the safety, fate, behavior and biologic effects of these particles on organisms and ecosystems. Titanium dioxide nanoparticles have been used extensively for a wide range of applications, e.g, self-cleaning surface coatings, solar cells, water treatment agents, topical sunscreens. Within this scenario increased environmental exposure can be expected but data on the ecotoxicological evaluation of nanoparticles are still scarce. The main purpose of this work was the evaluation of effects of TiO₂ nanoparticles in several organisms, covering different trophic levels, using a battery of aquatic assays. Using fish as a vertebrate model organism tissue histological and ultrastructural observations and the stress enzyme activity were also studied. TiO₂ nanoparticles (Aeroxide® P25), two phase composition of anatase (65%) and rutile (35%) with an average particle size value of 27.6±11 nm were used. Results on the EC₅₀ for the tested aquatic organisms showed toxicity for the bacteria, the algae and the crustacean, being the algae the most sensitive tested organism. The aquatic plant Lemna minor showed no effect on growth. The fish Carassius auratus showed no effect on a 21 day survival test, though at a biochemical level the cytosolic Glutathione-S-Transferase total activity, in intestines, showed a general significant decrease (p<0.05) after 14 days of exposure for all tested concentrations. The presence of TiO₂ nanoparticles aggregates were observed in the intestine lumen but their internalization by intestine cells could not be confirmed.     

Ecotoxicity studies of some organotin compounds

The ecotoxicities of three organic compounds containing spacer groups, an intermediate organotin premonomer, four organotin monomers, their homopolymers and six copolymers of tributylin α‐chloroacrylate (TCA) are reported against two microorganisms viz., Pseudomonas aeruginosa and Sarcina lutea and a larval species Anemia salina (Nauplii II). The organic compounds containing spacer group were less toxic whereas the monomers were found to be highly toxic. The homopolymers were found to be more toxic than that of tributyltin acrylate (TBTAA), tributyltin methacrylate (TBTMA) and tributyltin α‐Chloroacrylate (TCA). The toxicity of TCA copolymers increased with the increase in tributyltin (TBT) content in the polymer. From this study it was not possible to establish any relationship between the chemical nature of the comonomer with its toxicity.     

环境中有机紫外防晒剂残留及其生态毒性研究进展

有机紫外防晒剂被广泛添加在个人护理品中,随着日常使用源源不断地进入环境中,成为一类新兴污染物。环境介质中有机紫外防晒剂的检测及其生态毒理是目前的研究热点。概述了个人护理品中常用的有机紫外防晒剂,总结了有机紫外防晒剂在各类地表水、沉积物和生物体等不同介质中的浓度水平,详细分析了有机紫外防晒剂对鱼类的内分泌干扰效应和对水生无脊椎动物的急性毒性,为今后深入研究和科学评价这类新兴污染物提供重要参考。     

微塑料污染的水生生态毒性与载体作用

近年来微塑料的水生生态环境污染与生态毒害问题引起了科学界的广泛关注。在总结国内外相关研究的基础上,本文对水生态环境中微塑料的来源、形成与分布展开分析;对微塑料污染的生态毒性研究进展给予评述;并深入探讨了微塑料在生态系统中扮演的多重载体角色。鉴于微塑料污染的严峻现实,我国应尽快开展有关微塑料环境污染和生态毒理方面的系统研究,并辅以政策引导和经济支持。     

稀有鮈鲫作为化学品生态毒性测试鱼类模式生物的标准化实践

鱼类模式生物在化学品生态毒性测试中占有重要地位,中国尚没有合适的标准化本土实验鱼种。国家环境保护部第7号令《新化学物质环境管理办法》对本土受试生物用于生态毒性测试提出了要求。稀有鮈鲫(Gobiocypris rarus)是一种我国特有的小型淡水鲤科鱼类,具有成为标准试验鱼种的潜能。首个以稀有鮈鲫为标准供试生物的化学品鱼类急性毒性试验国家标准已经发布实施,其他测试方法的标准化工作正在持续进行中。本文阐述了研发稀有鮈鲫为标准供试生物的依据,对相关标准化研究工作进行了分析、归纳和总结,并提出了未来工作的方向和需求。     

Environmental assessment of ester-based lubricants after application

GOAL, SCOPE AND BACKGROUND: Lubricants based on renewable resources are an environmentally friendly alternative to petrochemical products due to their better ecotoxicological performance and their excellent biodegradability. To improve the technical performance of lubricants, and to reduce friction and wear, the use of additives is nowadays obligatory. The collaborative research center SFB 442 aims at developing environmentally acceptable lubricants that facilitate the avoidance of these additives by transferring their function to suitable coatings. For a complete assessment of the ecological performance of these newly developed lubricants, the whole life cycle including production, application as well as disposal and fate in the environment is studied. In the following study the focus was on the application and its influence on the environmental behavior of the lubricant. The application of lubricants leads, among other things, to the intake of metals due to abrasion from tools, work pieces or mechanical components. Previous examinations indicated a possible influence of metals on the toxicity of eluates prepared from used lubricants (Erlenkaemper et al. 2005). To clarify if the apparent toxicity of used lubricants solely results from the intake of metals, the extractability of these metals from the oil matrix is determined. By combining chemical analyses with bioassays, the bioavailability of metals that are present in the extract is estimated. To further investigate the relevance of metals on toxicity, toxic units (TU) were calculated and related to the results of the bioassays. Interactions between the metals were investigated with aqueous mixtures of metal chlorides and calculations based on the concept of concentration addition and independent action. METHODS: A lubricant mixture was applied to a tribological test bench that simulates real conditions of use and extremely short time load, respectively. Samples were taken at particular times, water soluble fractions (WSF) of these fluids were prepared and dilution series were investigated in several bioassays. Concentration of metals and total organic carbon (TOC) were determined in the eluates. TUs were calculated according to Sprague (1970) and mixture toxicity was calculated according to the concept of concentration addition (Loewe and Muischnek 1926) and independent action (Bliss 1939). RESULTS: Analyses of the metal content of the lubricant and the eluates clearly revealed the availability of the metals in the aqueous extracts. Especially copper, zinc, nickel and chromium were found and their concentrations increased during the time of use. The water extractable fraction, e.g., of copper, rose from 8.8% to 45.3% of the total content in the lubricant after 33.5 hours of use. Tests performed with the algal growth inhibition assay and the luminescence inhibition assay revealed the uptake or absorption by the organisms and, thus, the bioavailability of the metals. The calculation of TUs partly indicated a possible influence of the metals on ecotoxicity of the eluates. Copper reached concentrations equal to or higher than the EC50 value of copper chloride in the growth inhibition assays with algae and Ps. putida as well in the immobilization assay with daphnids. TUs for copper are also larger than 1 for the algal growth inhibition assay. The EL50 values indicated that the luminescence inhibition assay was the most sensitive test system, with values between 4.7% and 9.6%. While the toxicity towards algae and V. fischeri in the growth inhibition assay decreased until both organisms were no longer influenced by the exposure, the EL50 values for the D. magna immobilization assay and the Ps. putida growth inhibition assay decreased with the progressing use of the lubricant. The tested metal salt mixtures showed that Ps. putida, algae and daphnids are the most sensitive organisms with EC50 values below 1 mg/l. DISCUSSION: Although the intake of metals mainly occurred via abrasion of particles, the results revealed the availability of these metals in water. The availability varied for each of the four metals. For both the algal growth inhibition assay and the luminescence inhibition assay, an uptake or absorption of the metals could be demonstrated. The calculated TUs indicated an effect in some bioassays that was not verified in the test itself. The influence of copper on V. fischeri, for example, was not confirmed while the EL50 values for the daphnid bioassay decreased, meaning that the eluates became more toxic with progressing use of the lubricant. The calculations of mixture toxicity based on the concept of concentration addition demonstrated good correlations with the tested metal mixtures, but also a different sensitivity of the organisms. CONCLUSIONS: The results presented here reveal the availability of those metals in water that were taken in during the use of the lubricant in a tribological test bench and, thus, have the possibility of interacting with the organisms. The availability of the metals in the bioassays was proven by chemical analyses. The calculation of TUs and the corresponding EL50 values, however, indicate different availabilities of the metals. The results of the metal salt mixtures show good correlations with calculations of mixture toxicity based on concentration addition. Moreover, the varying sensitivity of the organisms when exposed to eluates or metal mixtures indicates a different bioavailability of the metals and/or the presence of other compounds that exert toxic action. RECOMMENDATIONS AND PERSPECTIVES: For further investigations, the organic oil matrix and its influence on the toxicity have to be taken into account. The toxicity of the eluates may not only be due to metals; additional effects could arise from changes in the lubricant itself.     

表面活性剂的生态毒理学及其应用研究进展

绝大多数表面活性剂如LAS、AS和AE易被分解,对环境和生物没构成严重的威胁;但部分表面活性剂的降解产物如NP具有潜在的危害,不容忽视。此外,表面活性剂具有增溶和增流作用,能促进疏水性有机污染物的去除,可应用于修复环境污染。