Zhang Yiwei, Liu Yuyan, Zhang Niuniu, Wang Zefeng, Chen Siwen, Liu Haofeng, Wu Dan, Zhang Lan
College of Geography and Environmental Science, Hainan Normal University, Haikou, 571158, Hainan, China; Key Laboratory of Earth Surface Processes and Environmental Change of Tropical Islands, Haikou, Hainan Province, China.
College of Geography and Environmental Science, Hainan Normal University, Haikou, 571158, Hainan, China; Key Laboratory of Earth Surface Processes and Environmental Change of Tropical Islands, Haikou, Hainan Province, China.
Chemosphere. 2023 Apr;320:138041. doi: 10.1016/j.chemosphere.2023.138041. Epub 2023 Feb 1.
Estuaries are environmental systems with great resource potential and environmental benefits. This study investigates the role of particulate palladium (Pd) in the Nandu River Estuary in the enrichment of estuarine geochemical processes during spring-neap tides. Particulate Pd was found to show different characteristics during spring-neap tides, with the hydrodynamic condition being one of the key factors causing the difference. In addition, particulate Pd showed a decreasing trend while moving from the mouth to the upstream. The highest value of particulate Pd was 35.32 ng L, which occurred at the intersection of the mainstream and the branch during the neap tide, and the lowest value was 0.86 ng·L, which occurred in the far mouth area during the spring tide. The concentrations of particulate Pd during the neap and spring tides were 5.53 (1.01-35.32) ng·L and 2.33 (0.86-5.22) ng·L, respectively. With the exception of stations 1, 5, 10, 11, and 15, the concentration of particulate Pd during the neap tide was greater than that during the spring tide. The variation in the particulate Pd was inconsistent between the spring tide and the neap tide, and the fluctuation in each study section during the neap tide was greater than that during the spring tide. In addition, since the emissions from catalytic converter are in the form of nanoparticles, they are difficult to be dissolve in natural water, and therefore, the concentration of particulate Pd was obviously greater in the waters near large bridges and main roads. An analysis of the physical and chemical properties of the water showed that Cl easily combined with dissolved Pd and was one of the important factors that affected the concentration of particulate Pd. In addition, DO and Eh had little effect on the change in the particulate Pd during the tidal cycle, and pH had a significant positive correlation with particulate Pd.
河口是具有巨大资源潜力和环境效益的环境系统。本研究调查了颗粒态钯（Pd）在南渡河河口大潮-小潮期间河口地球化学过程富集作用中的角色。研究发现，颗粒态Pd在大潮-小潮期间表现出不同特征，水动力条件是导致这种差异的关键因素之一。此外，颗粒态Pd从河口向河流上游移动时呈下降趋势。颗粒态Pd的最高值为35.32 ng·L，出现在小潮期间主流与支流交汇处；最低值为0.86 ng·L，出现在大潮期间的远河口区域。小潮和大潮期间颗粒态Pd的浓度分别为5.53（1.01 - 35.32）ng·L和2.33（0.86 - 5.22）ng·L。除站点1、5、10、11和15外，小潮期间颗粒态Pd的浓度大于大潮期间。大潮和小潮期间颗粒态Pd的变化不一致，各研究断面小潮期间的波动大于大潮期间。此外，由于催化转化器的排放物为纳米颗粒形式，难以溶解于天然水中，因此，大桥和主干道附近水域的颗粒态Pd浓度明显更高。对水体理化性质的分析表明，Cl容易与溶解态Pd结合，是影响颗粒态Pd浓度的重要因素之一。此外，溶解氧（DO）和氧化还原电位（Eh）对潮汐周期内颗粒态Pd的变化影响较小，pH与颗粒态Pd呈显著正相关。
