College of Geography and Environmental Science, Hainan Normal University, Haikou, Hainan, 571158, China.
Changji Environmental Monitoring Station, Changji, Xinjiang 831100, China.
Water Sci Technol. 2020 Jun;81(11):2450-2458. doi: 10.2166/wst.2020.303.
Palladium (Pd) is widely used in vehicle exhaust catalysts (VECs) to reduce toxic emissions from motor vehicles. The study aimed to quantitatively determine Pd content and water quality parameters, to analyze the variation differences and to explore the effect of water quality parameters on Pd content in the urban water environment system (wet deposition-rainfall runoff-receiving water body-estuary) of the city of Haikou, Hainan Island, China. The method used in this study included microwave digestion under high pressure and temperature, analysis by inductively coupled plasma mass spectrometry, quality control of the experimental procedure and guaranteed recovery (85% -125%). The results showed that the dissolved Pd average content in the urban water environment system was the highest in rainfall runoff (4.93 ng/L), followed by that in the receiving water body (4.56 ng/L), and it was the lowest in wet deposition (0.1 ng/L). The suspended Pd average content was the highest in the estuary (2.83 ng/L), followed by that in rainfall runoff (1.26 ng/L), and it was the lowest in wet deposition (6 × 10 ng/L). The particle-water partition ratio of the estuary Pd was the highest (1.26), followed by that of Pd in rainfall runoff (0.26). The particle-water partition ratio of the wet deposition Pd was the lowest (6 × 10). The dissolved Pd was correlated with the pH, Cl, and total suspended solids (TSS) (correlation coefficient = 0.52, -0.68, 0.39, p < 0.05; regression coefficient = 1.27, -1.39, 0.01). The suspended Pd was only correlated with Cl and TSS (correlation coefficient = -0.36, 0.76, p < 0.05; regression coefficient = -1.45, 0.01). Cl and TSS were the most closely related to Pd in the water environment system. Although individual factors such as pH, Cl, and TSS had certain migration and transformation effects on Pd in the wet deposition-rainfall runoff-receiving water body-estuary system, the probability of strong correlations was not high. In particular, Eh was not related to the dissolved nor suspended Pd content (correlation coefficient = 0.14, 0.13), which may be due to the synergistic effect of the multiple physical factors on Pd. This study was helpful to better understand the environmental behavior of Pd and provided important theoretical support for the prevention and protection against urban water environmental pollution.
钯（Pd）广泛用于汽车尾气催化剂（VEC）中，以减少机动车的有毒排放。本研究旨在定量测定钯含量和水质参数，分析变化差异，并探讨水质参数对中国海南岛海口市城市水环境系统（湿沉降-降雨径流-受纳水体-河口）中钯含量的影响。本研究采用的方法包括高温高压下的微波消解、电感耦合等离子体质谱分析、实验过程的质量控制和保证回收率（85%-125%）。结果表明，城市水环境系统中溶解态钯的平均含量在降雨径流中最高（4.93ng/L），其次是受纳水体（4.56ng/L），在湿沉降中最低（0.1ng/L）。悬浮态钯的平均含量在河口最高（2.83ng/L），其次是降雨径流（1.26ng/L），在湿沉降中最低（6×10ng/L）。河口钯的颗粒-水分配系数最高（1.26），其次是降雨径流中的钯（0.26）。湿沉降钯的颗粒-水分配系数最低（6×10）。溶解态钯与 pH、Cl 和总悬浮固体（TSS）呈正相关（相关系数=0.52、-0.68、0.39，p<0.05；回归系数=1.27、-1.39、0.01）。悬浮态钯仅与 Cl 和 TSS 呈负相关（相关系数=-0.36、0.76，p<0.05；回归系数=-1.45、0.01）。Cl 和 TSS 与水环境系统中的钯关系最密切。尽管 pH、Cl 和 TSS 等个别因素对湿沉降-降雨径流-受纳水体-河口系统中的钯具有一定的迁移转化作用，但强相关性的概率并不高。特别是 Eh 与溶解态和悬浮态钯含量均无关（相关系数=0.14、0.13），这可能是由于多种物理因素对钯的协同作用所致。本研究有助于更好地了解钯的环境行为，并为防治城市水环境污染提供了重要的理论支持。
