淡水水生生物对阿特拉津除草剂的敏感度

针对水环境中普遍存在的农药污染问题,以阿特拉津除草剂作为研究对象,梳理、整合阿特拉津对水生生态系统中不同营养级水生生物的急、慢性毒性数据,构建了基于对数-逻辑斯蒂分布的水生生物物种敏感度分布模型,分析并对比了阿特拉津对不同类群和不同区系水生生物急慢性毒性敏感度差异.结果表明,水生动物和植物、无脊椎动物(包括甲壳类、昆虫类、软体动物和蠕虫类)和脊椎动物(包括鱼类和两栖类动物)对阿特拉津敏感度均存在显著差异.分析了阿特拉津对不同类群水生生物的HC5(5%危险浓度)值,其中对水生动物和植物的急性毒性HC5值分别为4 257.94和12.55μg/L,慢性毒性的HC5值分别为2.47和1.95μg/L;对水生脊椎动物和无脊椎动物的HC5值分别为7 490.31和1 611.76μg/L;对甲壳类和鱼类的HC5值分别为1 201.16和6 639.90μg/L.在保护95%的物种水平下,不同类群试验生物对阿特拉津的敏感度排序为水生植物>水生动物、水生无脊椎动物>水生脊椎动物、甲壳类动物>鱼类.从统计学角度分析,中国水生动物与北美水生动物对阿特拉津的敏感度差异不显著.但是,中美两国间相对特有水生动物物种对阿特拉津的敏感度存在一定的差异.

Determining soil conservation strategies:Ecological risk thresholds of arsenic and the influence of soil properties

The establishment of ecological risk thresholds for arsenic(As)plays a pivotal role in developing soil conservation strategies.However,despite many studies regarding the toxicological profile of As,such thresholds varying by diverse soil properties have rarely been established.This study aims to address this gap by compiling and critically examining an extensive dataset of As toxicity data sourced from existing literature.Furthermore,to augment the existing information,experimental studies on As toxicity focusing on barley-root elongation were carried out across various soil types.The As concentrations varied from 12.01 to 437.25 mg/kg for the effective concentrations that inhibited 10%of barley-root growth(EC10).The present study applied a machine-learning approach to investigate the complex associations between the toxicity thresholds of As and diverse soil properties.The results revealed that Mn-/Fe-ox and clay content emerged as the most influential factors in predicting the EC10 contribution.Additionally,by using a species sensitivity distribution model and toxicity data from 21 different species,the hazardous concentration for x%of species(HCx)was calculated for four representative soil scenarios.The HC5 values for acidic,neutral,alkaline,and alkaline calcareous soils were 80,47,40,and 28 mg/kg,respectively.This study establishes an evidence-based methodology for deriving soil-specific guidance concerning As toxicity thresholds.

水生生物对三唑磷的物种敏感度分布研究

针对水环境中日益严重的有机磷农药污染问题,选择广泛使用的三唑磷作为研究对象,利用其对水生生态系统中不同营养层次生物物种的半数效应浓度(median effective concentration,EC50),建立了基于对数-逻辑斯蒂分布的水生生物物种敏感度分布(species sensitivity distribution,SSD)模型,并采用概率图和吻合度检验方法对该模型进行了检验和评价.结果表明,水生生物对三唑磷的SSD服从对数-逻辑斯蒂分布,其参数为α=-0.478 8±0.238 1,β=0.754 6±0.107 8.基于该SSD模型,获得三唑磷的5%危害浓度(hazardous concentration for 5%of the species,HC5)值为1.992×10-3 mg/L,并推导出三唑磷的最大浓度基准值(criteria maximum concentration,CMC)值为9.96×10-4 mg/L.对HC5、CMC与单一物种的安全浓度的比较研究指出,基于SSD方法制定环境质量标准更为严格,也更接近于真实的生态环境.另外,根据渤海莱州湾海域中三唑磷的监测数据,预测了其对物种的潜在影响比例(potentially affected fraction,PAF)为0.36%,对该水域生态环境的影响处于较低风险水平.

不同水体硬度条件下锌对本土水生生物急性毒性的影响

选取8种我国本土受试动物,在不同水体硬度(0~500 mg/L)下,探究锌的急性毒性变化,同时对锌的物种敏感度分布进行分析。实验结果表明:随着硬度的降低,水生生物对锌毒性效应增加;低营养级生物对锌毒性相对敏感性变化程度较大,而高营养级生物敏感性变化程度更小;物种敏感度分布法推导的5%生物短期毒性危害浓度HC 5分别为:7.1μg/L(硬度为0 mg/L)、63μg/L(硬度为50 mg/L)、67μg/L(硬度为100 mg/L)、230μg/L(硬度为250 mg/L)、367μg/L(硬度为400 mg/L)和476μg/L(硬度为500 mg/L)。可见,不同硬度条件下锌的短期危害浓度会有显著性差异。因此,在研究锌毒性效应和制定锌的水质标准时,不仅要考虑其毒性剂量效应关系,还应考虑水体中硬度对锌的生物有效性的影响。