Background

Many plants contain phytotoxic alkaloids to deter herbivorous pests and grazing animals. Alkaloids include quinolizidine and indole alkaloids found in the lupin (Lupinus spp.), an ornamental flower and emerging protein crop, as well as pyrrolizidine alkaloids in the ragwort (Senecio jacobaea), an invasive, weed-like flower. When lupins and ragworts are present in large densities in fields, there is a concern that alkaloids may leach into freshwater environments in amounts that may affect non-target organisms, such as Daphnia magna. This study aimed to investigate (i) the acute toxicity of alkaloids (gramine, heliotrine, lupanine, lupinine, monocrotaline, monocrotaline N-oxide, senecionine and sparteine) in D. magna, (ii) the contribution of these individual alkaloids to lupin plant extract toxicity, (iii) the longer term reproductive effects of a representative alkaloid, sparteine, and conclude with (iv) a tentative risk assessment for the sum of alkaloids measured in soil and surface waters.

Results

The alkaloids exhibited toxicity, with 48 h EC₅₀ values in the range of 5.6 to > 100 mg/L. The 48 h EC₅₀ of the Lupinus angustifolius plant extract was 1.38 mg/L, which was far more toxic than the simulated extract where lethality was < 10% at 10 mg/L after 48 h. Hence, non-measured compounds may have contributed to the joint toxicity. Daphnid mothers exposed to > 2.5 mg/L sparteine produced significantly fewer and smaller offspring during the 21-day exposure, making chronic effects occur at concentrations approximately 10-fold lower than the 48 h EC₅₀ for sparteine. The risk assessment of cumulated alkaloids measured in drain, running and pond waters showed a potential risk, particularly for stagnant pond water, where concentrations were severalfold higher than in the drain and running waters.

Conclusions

The results highlight that natural toxins may contribute to poor chemical quality of natural waters, and that natural toxins from upcoming crops or invasive weeds should be considered in aquatic risk assessments.

中文翻译：

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植物生物碱对水蚤的毒性和风险

背景

许多植物都含有植物毒性生物碱，可以阻止草食性害虫和放牧动物。生物碱包括在羽扇豆（羽扇豆属）中发现的喹oli嗪和吲哚生物碱（观赏花和新兴的蛋白质作物），以及在艾草（千里光）中的吡咯并idine啶生物碱（一种入侵的杂草样花）。当田间存在高密度的羽扇豆和豚草时，人们担心生物碱可能以影响非目标生物（如大型蚤）的量浸入淡水环境。本研究的目的是调查（ⅰ）生物碱（芦竹碱，heliotrine，lupanine，lupinine，野百合碱，野百合碱N-氧化物，senecionine和鹰爪豆碱）的急性毒性D.蚤；（ii）这些单独的生物碱对羽扇豆植物提取物毒性的贡献；（iii）代表性生物碱斯巴丁碱的长期生殖作用，并得出（iv）对土壤和土壤中所测生物碱总和进行初步风险评估。地表水。

结果

生物碱具有毒性，48 h EC ₅₀值在5.6至> 100 mg / L的范围内。在48小时EC ₅₀所述的羽扇豆的植物提取物为1.38毫克/升，这是比模拟提取其中致死率<10 mg / L的10％在48小时后为止的毒性更大。因此，无法测量的化合物可能会导致关节毒性。暴露于> 2.5 mg / L丹参碱的Daphnid母亲在21天暴露期间产生的后代明显更少和更小，使得慢性影响发生在浓度比48 h EC ₅₀低约10倍的情况下对于斯巴达因。在排水，自来水和池塘水中测量的生物碱累积风险评估显示出潜在的风险，特别是对于停滞的池塘水而言，那里的浓度比排水和自来水中的浓度高出几倍。

结论

结果表明，天然毒素可能导致天然水的化学质量较差，在水生风险评估中应考虑来自即将来临的作物或侵入性杂草的天然毒素。