Adams Merrin S, McKnight Kitty S, Spadaro David M, Binet Monique T, Hose Grant C, Fenton Stephen, Simpson Stuart L
CSIRO Environment, Lucas Heights, New South Wales, Australia.
School of Natural Sciences, Macquarie University, Macquarie Park, New South Wales, Australia.
Environ Toxicol Chem. 2024 Dec;43(12):2501-2514. doi: 10.1002/etc.5956. Epub 2024 Aug 13.
Barium (Ba) dissolution and mobilization in groundwater are predominantly controlled by sulfate because of the low solubility of barium sulfate (BaSO) minerals. Naturally present at low concentrations in groundwater, elevated concentrations of Ba can occur as a result of anthropogenic activities, including use of barite in drill operations, and geogenic sources such as leaching from geological formations. No toxicity data exist for Ba with groundwater organisms (stygofauna) to assess the risk of elevated Ba concentrations. The present study measured Ba toxicity to two stygobiont Cyclopoida species: one collected from Wellington and the other from Somersby, New South Wales, Australia. Toxicity was measured as cyclopoid survival over 2, 4, 7, 14, 21, and 28 days in waters of varying sulfate concentration (<1-100 mg SO/L). When sulfate was present, dissolved Ba concentrations decreased rapidly in toxicity test solutions forming a BaSO precipitate until dissolved sulfate was depleted. Barium in excess of sulfate remained in the dissolved form. The toxicity of Ba to cyclopoids was clearly attributed to dissolved Ba. Precipitated Ba was not toxic to the Wellington cyclopoid species. Toxicity values for dissolved Ba for the Wellington and Somersby cyclopoid species included a (21-day) no-effect concentration of 3.3 mg/L and an effective concentration to cause 5% mortality of 4.8 mg/L (at 21 days). Elevated dissolved Ba concentrations due to anthropogenic and/or biogeochemical processes may pose a risk to groundwater organisms. Further toxicity testing with other stygobiont species is recommended to increase the data available to derive a guideline value for Ba that can be used in contaminant risk assessments for groundwaters. Environ Toxicol Chem 2024;43:2501-2514. © 2024 The Author(s). Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.
由于硫酸钡（BaSO₄）矿物的低溶解度，地下水中钡（Ba）的溶解和迁移主要受硫酸盐控制。地下水中天然存在的钡浓度较低，但由于人为活动，包括在钻探作业中使用重晶石，以及地质成因来源，如地质构造的淋滤作用，钡的浓度可能会升高。目前尚无关于钡对地下水生物（洞穴动物）毒性的数据来评估钡浓度升高的风险。本研究测定了钡对两种穴居剑水蚤物种的毒性：一种采自惠灵顿，另一种采自澳大利亚新南威尔士州的萨默斯比。毒性通过在不同硫酸盐浓度（<1 - 100 mg SO₄²⁻/L）的水中，两种穴居剑水蚤在2、4、7、14、21和28天的存活情况来衡量。当存在硫酸盐时，毒性测试溶液中的溶解钡浓度迅速下降，形成硫酸钡沉淀，直到溶解的硫酸盐耗尽。过量的钡以溶解形式存在。钡对剑水蚤的毒性显然归因于溶解态钡。沉淀态钡对惠灵顿剑水蚤物种无毒。惠灵顿和萨默斯比剑水蚤物种的溶解钡毒性值包括（21天）无效应浓度为3.3 mg/L，以及导致5%死亡率的有效浓度为4.8 mg/L（在21天时）。由于人为和/或生物地球化学过程导致的溶解钡浓度升高可能对地下水生物构成风险。建议对其他穴居生物物种进行进一步的毒性测试，以增加可用于推导钡的指导值的数据，该指导值可用于地下水污染物风险评估。《环境毒理学与化学》2024年；43:2501 - 2514。© 2024作者。《环境毒理学与化学》由威利期刊有限责任公司代表SETAC出版。
