Toxicity Assessment of Binary Metal Mixtures (Copper–Zinc) to Nitrification in Soilless Culture with the Extended Biotic Ligand Model

详细信息    查看全文

• 作者：Aiju Liu ; JinXin Li ; Menghong Li…
• 刊名：Archives of Environmental Contamination and Toxicology
• 出版年：2017
• 出版时间：February 2017
• 年：2017
• 卷：72
• 期：2
• 页码：312-319
• 全文大小：
• 刊物类别：Earth and Environmental Science
• 刊物主题：Ecotoxicology; Pollution, general; Environmental Health; Environmental Chemistry; Soil Science & Conservation; Monitoring/Environmental Analysis;
• 出版者：Springer US
• ISSN：1432-0703
• 卷排序：72

文摘

Metals are always found in the environment as mixtures rather than as solitary elements. Only a limited number of studies have developed appropriate models that incorporate bioavailability to estimate the toxicity of heavy-metal mixtures. In the present study, we explored the applicability of two extended biotic ligand model (BLM) approaches—BLM-f_mix and BLM-toxicity unit (TU)—to predict and interpret mixture toxicity with the assumption that interactions between metal ions obey the BLM theory. Exposure assays of single and mixed metals were performed with inoculums of an ammonia-oxidizing bacterium SD5 isolated from soil. Nitrification of the cultures was the end point used to quantify the toxic response. The results indicated that the developed BLM-f_mix approach could well estimate the single toxicity of Cu2+ and Zn2+ as well as their binary mixture toxicity to nitrification with >90% of toxicity variation explained. Assuming that metal ions compete with each other for binding at a single biotic ligand, the BLM-f_mix approach (root-mean-square error [RMSE] = 19.66, R2 = 0.8879) showed better predictive power than the BLM-TU approach (RMSE = 31.12, R2 = 0.6892). The present study supports the use of the accumulation of metal ions at the biotic ligands as predictor of toxicity of single metals and metal mixtures.