Abstract

In this study, we investigated concentrations and profiles of polycyclic aromatic hydrocarbons (PAHs) in rainwater and surface water samples collected in Saitama, an urban city located in Japan. The volume-weighted mean concentration of total PAHs in rainwater samples (dissolved + particulate) was 108.8 ng L⁻¹ with a range of 17.6–192.9 ng L⁻¹. Two and three benzene ring PAHs were predominantly detected, occupying 67.0% of the total concentration in rainwater samples. Individual PAH concentrations were negatively correlated with their K_ow, suggesting that low-molecular-weight PAHs are preferentially scavenged owing to the higher hydrophilicity. The toxic equivalent calculated based on the relative potencies of individual PAHs showed high toxic contributions by chrysene and benz[a]anthracene in the rainwater samples. Those PAHs levels in rainwater were comparable or higher than those in adjacent river water. Correlation coefficient of PAH signatures between rainwater and surface water samples was high particularly in the dissolved phase, supporting the source/sink relationships of PAHs between wet deposition samples and receiving waters. The mean deposition flux of PAHs was 2000 ng m⁻² and considered to increase with precipitation amounts.

摘要

在这项研究中，我们调查了在日本城市埼玉市采集的雨水和地表水样品中多环芳烃 (PAHs) 的浓度和分布。雨水样品（溶解+颗粒）中总 PAHs 的体积加权平均浓度为 108.8 ng L ^-1，范围为 17.6-192.9 ng L ^-1。主要检测到两个和三个苯环多环芳烃，占雨水样品总浓度的 67.0%。个体 PAH 浓度与其K _{ow呈负相关}，表明由于较高的亲水性，低分子量的 PAHs 被优先清除。根据单个 PAHs 的相对效力计算的毒性当量表明，雨水样品中的 chrysene 和苯并[a]蒽具有很高的毒性贡献。雨水中的多环芳烃水平与邻近河水中的水平相当或更高。雨水和地表水样品之间多环芳烃特征的相关系数很高，特别是在溶解相，这支持了湿沉降样品和接收水之间多环芳烃的源/汇关系。PAHs 的平均沉积通量为 2000 ng m ^-2并且被认为随着降水量的增加而增加。