Comparison of five methods for measuring sediment toxicity of hydrophobic contaminants.
Comparison of five methods for measuring sediment toxicity of hydrophobic contaminants.
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DOI：
10.1021/es071911c
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发表时间：
2007-11
影响因子：
11.4
通讯作者：
Yiping Xu;F. Spurlock;Zijian Wang;J. Gant
中科院分区：
文献类型：
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作者：
Yiping Xu;F. Spurlock;Zijian Wang;J. Gant
疏水有机化合物(HOCs)的沉积物毒性因多相之间的化学分配和沉积物特定的生物利用度而变得复杂。在这项研究中，我们使用三种疏水性拟除虫菊酯类杀虫剂作为测试化合物，得出了三种不同沉积物中摇蚊的10天半致死浓度(LC_(50))。LC_(50)用HOC浓度(C(S))、有机碳(OC)-归一化沉积物(C(S-OC))、孔水基(C(PW))、溶解有机碳(DOC)-归一化孔水基(C(PW-DOC))和自由溶解孔水基(C(游离))来表示。体相C(S)和C(PW)在不同沉积物类型中产生高度可变的LC_(50)，而归一化浓度C(S-OC)和C(PW-DOC)的使用通常降低了因沉积物类型而不是由于老化而引起的变异性。相反，基于C(游离态)的LC_(50)基本上与沉积物条件无关。沉积物孔隙水样中含有约20-90 mg L(-1)DOC，在不同沉积物中，甲氰菊酯(平均=19%)、联苯菊酯(平均=13%)和氟氯氰菊酯(平均=6%)的C(游离态)占总孔隙水浓度的百分比在9-28%、8%-18%和3%-8%之间。这些结果表明，C(游离态)的使用减少了沉积物变量引起的不确定性，如有机碳特性和老化效应。
Sediment toxicity from hydrophobic organic compounds (HOCs) is complicated by chemical partitioning among multiple phases and sediment-specific bioavailability. In this study, we used three hydrophobic pyrethroid insecticides as test compounds and derived 10-d median lethal concentrations (LC50s) for Chironomus tentans in three different sediments. The LC50s were expressed using HOC concentrations on a bulk sediment basis (C(S)), organic carbon (OC)-normalized sediment basis (C(S-OC)), porewater basis (C(PW)), dissolved organic carbon (DOC)-normalized porewater basis (C(PW-DOC)), and freely dissolved porewater basis (C(free)). The bulk phase C(S) and C(PW) yielded highly variable LC50s across sediment types, whereas the use of normalized concentrations C(S-OC) and C(PW-DOC) generally reduced variability due to sediment type but not that due to aging. In contrast, LC50s based on C(free) were essentially independent of sediment conditions. The sediment pore water samples contained approximately 20-90 mg L(-1) DOC, and the C(free) expressed as a percentage of the total bulk pore water concentration ranged from 9 to 28% for fenpropathrin (mean = 19%), 8 to 18% for bifenthrin (mean = 13%), and 3 to 8% for cyfluthrin (mean = 6%) across the different sediments. These results indicate thatthe use of C(free) reduces uncertainties caused by sediment variables such as OC properties and aging effects.