Mäenpää Kimmo A, Sormunen Arto J, Kukkonen Jussi V K
Department of Biology, University of Joensuu, P.O. Box 111, 80101, Joensuu, Finland.
Ecotoxicol Environ Saf. 2003 Nov;56(3):398-410. doi: 10.1016/s0147-6513(03)00010-1.
The benthic macroinvertebrates Lumbriculus variegatus and Chironomus riparius were used in toxicity and bioaccumulation tests to determine the toxic concentrations and accumulation potential of sediment associated herbicides. The tested chemicals were ioxynil, bentazone, and pendimethalin. The bioaccumulation tests with L. variegatus were performed in four different sediments, each having different characteristics. Water-only LC(50) tests were performed with both L. variegatus and C. riparius. A sublethal effect of model compounds in sediments was assessed by a C. riparius larvae growth-inhibition test. Of the model compounds, ioxynil appeared to be the most toxic, with LC(50) values 1.79 and 2.79 mgL(-1) for L. variegatus and C. riparius, respectively. The LC(50) water concentrations for bentazone were 79.11 and 62.31 mgL(-1) for L. variegatus and C. riparius, respectively. Similarly, ioxynil revealed the highest bioaccumulation potential in bioaccumulation tests. The most important characters affecting chemical fate in the sediment seemed to be the organic matter content and the particle size fraction. The sediments with low organic material and coarse particle size consistently showed high bioaccumulation potential and vice versa. In C. riparius growth tests bentazone had a statistically significant effect on larval growth at sediment concentrations of 1160 and 4650 mgkg(-1) (P<0.05). It is noteworthy that standard deviations tend to be greater at high chemical concentrations, which addresses the fact that part of the individuals started to suffer. Ioxynil had an effect on the larval growth in other test sediment at the highest concentration (15.46 mgkg(-1)dw), in which head capsule length correlated with larval weight, decreasing toward higher exposure concentrations. The current results show the importance of sediment organic matter as a binding site of xenobiotics.
底栖大型无脊椎动物颤蚓和摇蚊被用于毒性和生物累积测试，以确定沉积物相关除草剂的毒性浓度和累积潜力。测试的化学物质为碘苯腈、灭草松和二甲戊灵。对颤蚓进行的生物累积测试在四种具有不同特性的沉积物中进行。对颤蚓和摇蚊都进行了仅水相的半数致死浓度（LC(50)）测试。通过摇蚊幼虫生长抑制测试评估了沉积物中模型化合物的亚致死效应。在模型化合物中，碘苯腈似乎毒性最大，颤蚓和摇蚊的LC(50)值分别为1.79和2.79 mgL(-1)。灭草松对颤蚓和摇蚊的LC(50)水相浓度分别为79.11和62.31 mgL(-1)。同样，在生物累积测试中碘苯腈显示出最高的生物累积潜力。影响沉积物中化学物质归宿的最重要特征似乎是有机质含量和颗粒大小分级。有机物质含量低且颗粒尺寸粗的沉积物始终显示出高生物累积潜力，反之亦然。在摇蚊生长测试中，灭草松在沉积物浓度为1160和4650 mgkg(-1)时对幼虫生长有统计学显著影响（P<0.05）。值得注意的是，在高化学浓度下标准偏差往往更大，这说明了部分个体开始受到影响这一事实。在其他测试沉积物中，碘苯腈在最高浓度（15.46 mgkg(-1)干重）时对幼虫生长有影响，其中头壳长度与幼虫体重相关，随着暴露浓度升高而降低。当前结果表明沉积物有机质作为异生物素结合位点的重要性。
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