State University of Campinas (UNICAMP), Limeira, Paschoal Marmo, 1888 - Jd. Nova Itália, 13484-332, Limeira/SP, Brazil.
Environ Monit Assess. 2023 Feb 3;195(3):359. doi: 10.1007/s10661-023-10969-5.
Zinc (Zn) is an essential micronutrient for plants and an important component for maintaining soil quality. Commonly found in the soil due to anthropogenic activities, such as industrialization and application of organic waste as fertilizers, in high concentrations, Zn may induce soil toxicity, affecting important communities, such as edaphic fauna. Despite its high concentrations found in the environment, Zn bioavailability can be affected by the type of soil, organic matter content and pH. In this work, Zn had its toxicity evaluated in a natural tropical soil, sampled in São Paulo-Brazil, for two soil invertebrates (Folsomia candida, Enchytraeus crypticus) and two seeds (Lactuca sativa and Phaseolus vulgaris), through ecotoxicological tests. The invertebrate E. crypticus was exposed to Zn concentrations of 10.0 (T1); 100.0 (T2); 150.0 (T3); 200.0 (T4); 400.0 (T5) mg Zn kg of dry soil, while F. candida, L. sativa and P. vulgaris were exposed to Zn concentrations of 100.0; 200.0; 400.0; 800.0 (t6); 1600.0 (t7); and 2000.0 (t8) mg Zn kg of dry soil. The outcome evaluated were seed germination, for L. sativa and P. vulgaris, and reproduction, for F. candida and E. crypticus. The EC50 obtained for E. crypticus, F. candida, L. sativa, and P. vulgaris were 261.5, 1089.7, 898.5, and 954.5 mg Zn kg of dry soil, respectively, being E. crypticus the most sensitive organism, and only at the highest Zn's concentrations the organisms' reproduction and seeds' germination showed a statistically significant inhibitory effect (p < 0.05). Therefore, this work's results showed that Zn does not present significant toxicity for the tested soil organisms and seeds and that at 100 mg Zn kg of dry soil it can be beneficial to F. candida and E. crypticus' reproduction and L. sativa's germination. These results imply that the presence of Zn in low concentrations, both in soil and biofertilizers, such as sewage sludge, not only is not a concern, but it can even benefit certain crops and functions of edaphic organisms, which may contribute to the engagement of sustainable agricultural practices and the quest for food security.
锌（Zn）是植物必需的微量元素，也是维持土壤质量的重要组成部分。由于人为活动，如工业化和有机废物作为肥料的应用，锌通常在土壤中含量很高，在高浓度下，锌可能会导致土壤毒性，影响土壤动物等重要群落。尽管环境中锌的浓度很高，但锌的生物利用度可能受到土壤类型、有机质含量和 pH 值的影响。在这项工作中，通过生态毒理学测试，评估了在巴西圣保罗采集的天然热带土壤中两种土壤无脊椎动物（Folsomia candida，Enchytraeus crypticus）和两种种子（生菜和菜豆）对锌的毒性。无脊椎动物 E. crypticus 暴露于 10.0（T1）；100.0（T2）；150.0（T3）；200.0（T4）；400.0（T5）mg Zn kg 干土，而 F. candida、生菜和菜豆则暴露于 100.0；200.0；400.0；800.0（t6）；1600.0（t7）；和 2000.0（t8）mg Zn kg 干土。评估的结果是生菜和菜豆的种子发芽，以及 F. candida 和 E. crypticus 的繁殖。E. crypticus、F. candida、生菜和菜豆的 EC50 分别为 261.5、1089.7、898.5 和 954.5 mg Zn kg 干土，E. crypticus 是最敏感的生物，只有在最高浓度的锌下，生物的繁殖和种子的发芽才显示出统计学上显著的抑制作用（p < 0.05）。因此，这项工作的结果表明，锌对所测试的土壤生物和种子没有显著的毒性，在 100 mg Zn kg 干土的浓度下，它可以有益于 F. candida 和 E. crypticus 的繁殖和生菜的发芽。这些结果表明，低浓度的锌，无论是在土壤中还是在生物肥料（如污水污泥）中，不仅不是问题，甚至可以有益于某些作物和土壤生物的功能，这可能有助于可持续农业实践的参与和对粮食安全的追求。
