醋酸盐类城市道路抑尘剂的生态毒性及生物降解特性

醋酸盐类抑尘剂因其具有良好的抑尘效果和生态友好性,被越来越多地用于城市道路抑尘.为了揭示醋酸盐类抑尘剂的水生态效应,选取水环境中占据不同生态位的4种水生生物(发光细菌、羊角月牙藻、大型溞和青鳉鱼)进行急性毒性测试.结果表明:4种水生生物对醋酸盐类抑尘剂的敏感程度依次为羊角月牙藻>大型溞>青鳉鱼>发光细菌.确定了抑尘剂与大型溞、发光细菌、青鳉鱼的剂量-效应关系,抑尘剂对三者的EC₅₀/LC₅₀(半数效应浓度/半致死浓度)分别为1.29、37.6、32.7 g/L.抑尘剂对羊角月牙藻的急性毒性及其质量浓度之间没有呈现出明确的数量关系,但是可推断EC₅₀为mg/L量级.以此为基础,推断醋酸盐类抑尘剂的预测无效应浓度范围为21.8～177 μg/L.不同温度下抑尘剂在水中的生物降解速率结果显示,在5和25 ℃时,醋酸盐类抑尘剂均易被降解,主要是微生物和藻类的共同降解作用所致.研究显示,醋酸盐类抑尘剂易于生物降解且生态毒性较低,但在使用时应注意区域总量控制,以防止对水生生物造成潜在威胁. 

Eco-Toxicity and Biodegradation of an Acetate Urban Road Dust Suppressant

Acetate dust suppressant is increasingly used to control dust on city roads due to its high efficiency and eco-friendly property. In order to reveal its ecological effect, four aquatic species(Daphnia magna, Luminescent bacteria, Oryzias latipes and Selenastrum capricornutum) which live in different ecological niches were selected to test the acute toxicity of acetate dust suppressant. The results showed that the sensitivity of the four species to acetate dust suppressant could be ranked as follows:S.capricornutum>D.magna>O.latipes>L.bacteria.Moreover, the dose-effect relationships with D.magna, L.bacteria and O.latipes were determined, and the EC₅₀/LC₅₀(median lethal/effective concentrations) for the three organisms were obtained to be 1.29,37.6 and 32.7 g/L, respectively. The acute toxicity of rust suppressant to S.capricornutum showed no obvious relationship with its concentration,but the EC₅₀ could be induced to be at the mg/L level. On this basis, the predicted environmental concentration of acetate dust suppressant was inferred to be in the range of 21.8-177 μg/L. In addition, the biodegradation ratesat different temperatures were investigated. The acetate dust suppressant could be biodegraded easily in natural water at 5 and 25 ℃, because of the combined contribution of microbes and algae. In a word, acetate dust suppressant is easily biodegraded and has low ecological toxicity. However, the regional total amount should be controlled in dust suppressant application, to prevent potential risks to aquatic organisms.