Direct and interacting toxicological effects on the waterflea (Daphnia magna) by natural organic matter, synthetic humic substances and cypermethrin.
Direct and interacting toxicological effects on the waterflea (Daphnia magna) by natural organic matter, synthetic humic substances and cypermethrin.
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DOI：
10.1016/s0048-9697(03)00445-5
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发表时间：
2004-02
期刊：
影响因子：
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通讯作者：
Nanke Meems;Christian E. W. Steinberg;Claudia Wiegand
中科院分区：
文献类型：
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作者：
Nanke Meems;Christian E. W. Steinberg;Claudia Wiegand
腐殖物质是所有水生生态系统中溶解性有机物的主要组成部分，由多种分子结构和功能基团组成。它们与有机污染物和金属结合，从而降低了生物利用度，并因此在大多数情况下降低了这些物质的毒性。最近的研究还描述了对生物体的直接相互作用和影响。目前的研究还表明，在某些情况下，天然有机物浓度较低时，缓解效果更强，毒性随着天然有机物浓度的增加而增加。我们假设，在较高的浓度下，NOM本身的直接影响会覆盖缓解效果，因此这些方面进行了综合研究。因此，一方面，这项研究表明，毒性参数和大型蚤的转化酶系统的活性的直接影响，引起两个NOM和一个合成的类腐殖酸物质，HS 1500。另一方面，NOM和合成HS 1500的能力，以减轻杀虫剂氯氰菊酯的影响进行了研究。综合来看，NOM和HS 1500的直接自身效应覆盖了缓解效应。使用的NOM是从Suwannee河（XAD，2000年春季）和Svartberget森林（反渗透，2000年春季）的溪流中分离的。HS 1500是通过对苯二酚的自由基自氧化合成的。Suwannee河NOM在50和100毫克/升之间的浓度，和HS 1500（10-50毫克/升），但不是Svartberget NOM增加的不动性和致死性的水蚤。从0.5 mg/l（HS 1500）、1.0 mg/l（Suwannee River NOM）和10 mg/l（Svartberget NOM）开始，所有这些都提高了可溶性谷胱甘肽S-转移酶的活性，微粒体谷胱甘肽S-转移酶没有反应。谷胱甘肽过氧化物酶有升高的趋势。在单次接触中，杀虫剂氯氰菊酯增加了所有毒理学参数，在0.001和1.0 μg/l之间增加了可溶性和倾向性微粒体谷胱甘肽S-转移酶活性，并倾向性增加了谷胱甘肽过氧化物酶。与此相反，50 mg/l的NOM和HS 1500没有减轻毒理学效应。与氯氰菊酯单独使用相比，HS 1500与氯氰菊酯联合使用甚至增加了不动性。NOM或HS 1500浓度的增加与氯氰菊酯的组合并没有增加缓解，如在可溶性谷胱甘肽S-转移酶的活性中所见，微粒体谷胱甘肽S-转移酶和谷胱甘肽过氧化物酶的活性甚至降低，相对于对照，这可能是酶功能障碍或细胞中的进一步损伤的暗示。浓度的增加并没有增加缓解。NOM或HS 1500浓度越低，其缓解效果越好，这可能是由于NOM或HS 1500本身的直接作用。因此，直接效应对于分析缓解质量是相关的。
Humic substances are the main component of dissolved organic matter in all aquatic ecosystems, comprising a variety of molecular structures and functional groups. They bind organic pollutants and metals, thereby decreasing the bioavailability and consequently the toxicity of these substances in most instances. Recent studies also describe direct interactions and effects on organisms. Current studies also show that in some cases mitigation effects are stronger at lower concentrations of natural organic matter (NOM) and that toxicity increases with increased NOM concentrations. We hypothetise that at higher concentrations the mitigating effects are overlayed by direct effects of NOM themselves, thus these aspects were investigated in combination. So, on the one hand, this study demonstrates direct effects on toxicological parameters and activities of transformation enzyme systems of Daphnia magna, provoked by two NOM and one synthetic humic-like substance, HS1500. On the other hand, capacities of NOM and synthetic HS1500 to mitigate effects of the insecticide cypermethrin were investigated. Taken together, mitigation effects were overlayed by direct own effects of the NOM and HS1500. The NOM used were isolates from Suwannee River (XAD, Spring 2000) and from streams of the Svartberget forest (reverse osmosis, Spring 2000). The HS1500 was synthetically produced by radicalic autoxidation of hydroquinones. Suwannee River NOM at concentrations between 50 and 100 mg/l, and HS1500 (10–50 mg/l), but not Svartberget NOM increased immobility and lethality of the daphnids. All elevated the activity of the soluble glutathione S-transferase from 0.5 mg/l (HS1500), 1.0 mg/l (Suwannee River NOM) and 10 mg/l (Svartberget NOM) onwards, the microsomal glutathione S-transferase did not react. The glutathione peroxidase tended to increase. In the single exposure, the insecticide cypermethrin increased all toxicological parameters, elevated soluble and tendentially microsomal glutathione S-transferase activity between 0.001 and 1.0 μg/l and tendentially increased glutathione peroxidase. In contrast to that, 50 mg/l of the NOM and HS1500 did not mitigate toxicological effects. HS1500 in combination with cypermethrin even increased immobility, compared to cypermethrin alone. Increase of the NOM or HS1500 concentrations in combination with cypermethrin did not increase mitigation as seen in the activity of soluble glutathione S-transferases, activities of microsomal glutathione S-transferase and glutathione peroxidase even decreased, relative to control, which can be a hint of enzyme disfunction or further damages in the cell. An increase of concentration did not increase mitigation. Mitigation was higher at lower NOM or HS1500 concentration, probably as a consequence of the direct effects caused by themselves. Consequently, direct effects are relevant for analysing the mitigation qualities.