Department of Earth Science and Engineering, Royal School of Mines, Imperial College London, Exhibition Road, London SW7 2AZ, UK.
Department of Earth Science and Engineering, Royal School of Mines, Imperial College London, Exhibition Road, London SW7 2AZ, UK.
Sci Total Environ. 2015 Dec 15;538:385-401. doi: 10.1016/j.scitotenv.2015.06.120. Epub 2015 Aug 25.
Although significant progress has been made in understanding how environmental factors modify the speciation, bioavailability and toxicity of metals such as copper in aquatic environments, the current methods used to establish water quality standards do not necessarily consider the different geological and geochemical characteristics of a given site and the factors that affect copper fate, bioavailability potential and toxicity. In addition, the temporal variation in the concentration and bioavailable metal fraction is also important in freshwater systems. The work presented in this paper illustrates the temporal and seasonal variability of a range of water quality parameters, and Cu speciation, bioavailability and toxicity at four freshwaters sites in the UK. Rivers Coquet, Cree, Lower Clyde and Eden (Kent) were selected to cover a broad range of different geochemical environments and site characteristics. The monitoring data used covered a period of around six years at almost monthly intervals. Chemical equilibrium modelling was used to study temporal variations in Cu speciation and was combined with acute toxicity modelling to assess Cu bioavailability for two aquatic species, Daphnia magna and Daphnia pulex. The estimated copper bioavailability, toxicity levels and the corresponding ecosystem risks were analysed in relation to key water quality parameters (alkalinity, pH and DOC). Although copper concentrations did not vary much during the sampling period or between the seasons at the different sites; copper bioavailability varied markedly. In addition, through the chronic-Cu BLM-based on the voluntary risk assessment approach, the potential environmental risk in terms of the chronic toxicity was assessed. A much higher likelihood of toxicity effects was found during the cold period at all sites. It is suggested that besides the metal (copper) concentration in the surface water environment, the variability and seasonality of other important water quality parameters should be considered in setting appropriately protective environmental quality standards for metals.
尽管在理解环境因素如何改变水生环境中金属（如铜）的形态、生物可利用性和毒性方面已经取得了重大进展，但目前用于制定水质标准的方法并不一定考虑到特定地点的不同地质和地球化学特征以及影响铜命运、生物可利用潜力和毒性的因素。此外，在淡水系统中，金属浓度和生物可利用金属部分的时间变化也很重要。本文介绍了英国四个淡水地点的一系列水质参数、Cu 形态、生物可利用性和毒性的时间和季节性变化。Coquet、Cree、Lower Clyde 和 Eden（肯特）河流被选为涵盖广泛的不同地球化学环境和地点特征。使用的监测数据涵盖了大约六年的时间，几乎每月间隔一次。化学平衡建模用于研究 Cu 形态的时间变化，并与急性毒性建模相结合，以评估两种水生物种（大型溞和水蚤）的 Cu 生物可利用性。根据关键水质参数（碱度、pH 值和 DOC），分析了估计的铜生物可利用性、毒性水平和相应的生态系统风险。尽管在采样期间或不同地点的不同季节铜浓度变化不大，但铜的生物可利用性变化显著。此外，通过基于慢性-Cu BLM 的自愿风险评估方法，评估了慢性毒性方面的潜在环境风险。在所有地点，寒冷期发生毒性作用的可能性都要高得多。建议在制定金属的适当保护水质标准时，除了地表水环境中的金属（铜）浓度外，还应考虑其他重要水质参数的可变性和季节性。
