SPAWAR Systems Center Pacific, San Diego, CA 92152, USA.
Ecotoxicol Environ Saf. 2011 Oct;74(7):1921-30. doi: 10.1016/j.ecoenv.2011.06.023. Epub 2011 Aug 15.
Experimental materials currently being investigated for use as amendments for the in situ remediation of contaminated sediments were assessed for their potential impacts on marine benthos. Laboratory toxicity tests involving lethal and sublethal endpoints were conducted on sediments amended with apatite, organoclay, chitin, or acetate, with the polychaete Neanthes arenaceodentata, the amphipod Eohaustorius estuarius, and the larval sheepshead minnow Cyprinodon variegatus. Amendments were mixed loosely into uncontaminated or metal-contaminated sediments, and also added inside experimental geotextile mats, at sediment dry weight (dw) concentrations ranging from 0.5% to 10%. The geotextile mats, containing apatite (5 or 10% dw), and/or organoclay (5%) did not result in adverse effects on any of the test organisms. Chitin and acetate, however, repetitively resulted in adverse effects on survival and/or adverse or positive effects on organism growth at concentrations of ≤ 2.5% dw. The adverse effects were attributed to water quality degradation in the exposure vessels (notably ammonia and dissolved oxygen concentration, for chitin and acetate, respectively) as a result of the microbial breakdown of the amendments. For N. arenaceodentata, growth was enhanced in the presence of chitin at concentrations as low as 0.5% sediment dw, which stimulated bacterial growth that may have provided an additional food source for the polychaete. Sediment chitin concentrations of 0.5% resulted in a statistically significant reduction in N. arenaceodentata body burdens of 61%, 29%, and 54%, relative to unamended contaminated sediment, for Cu, Zn, and Cd, respectively. The studies suggest a lack of inherent toxicity of these materials on the experimental organisms, as the adverse or positive responses observed are likely related to artifacts associated with laboratory exposure. Assessments in field settings are needed to verify this conclusion.
目前正在研究将实验材料作为原位修复受污染沉积物的改良剂，以评估它们对海洋底栖生物的潜在影响。在含有磷灰石、有机粘土、甲壳素或醋酸盐的沉积物中进行了涉及致死和亚致死终点的实验室毒性测试，使用多毛类环节动物 Neanthes arenaceodentata、甲壳类动物 Eohaustorius estuarius 和幼鱼 Cyprinodon variegatus。改良剂松散地混合到未受污染或金属污染的沉积物中，也添加到实验土工织物垫内，沉积物干重（dw）浓度范围为 0.5%至 10%。含有磷灰石（5 或 10%dw）和/或有机粘土（5%）的土工织物垫对任何测试生物均无不良影响。然而，甲壳素和醋酸盐在浓度≤2.5%dw 时，重复导致生存不良和/或对生物生长产生不良或积极影响。这些不良影响归因于暴露容器中水质恶化（对甲壳素和醋酸盐分别为氨和溶解氧浓度），这是由于改良剂的微生物分解所致。对于 N. arenaceodentata，在低至 0.5%沉积物 dw 的甲壳素存在下，其生长得到增强，这刺激了细菌生长，可能为多毛类动物提供了额外的食物来源。沉积物甲壳素浓度为 0.5%，与未添加污染沉积物相比，Cu、Zn 和 Cd 的 N. arenaceodentata 体内负荷分别降低了 61%、29%和 54%。这些研究表明，这些材料对实验生物没有内在毒性，因为观察到的不良或积极反应可能与实验室暴露相关的假象有关。需要在现场环境中进行评估，以验证这一结论。
