珠江口和南海北部海水中的总溶解无机As

利用氢化物发生-原子荧光光谱法（HG-AFS）分别对2014年10月和2015年6月珠江口、南海北部总溶解无机As（TDIAs，TDIAs]＝As5+]+As3+]）的含量进行了测定，以探讨TDIAs在珠江口和南海北部的分布及其影响因素。夏季和秋季珠江口TDIAs的含量不存在显著性季节差异（t检验，置信度为95%）。夏、秋季珠江口TDIAs均呈现不保守混合行为，尤其在河海混合初期清除现象较明显，其清除百分数均在30%左右。珠江口向南海TDIAs的年输送通量约为（4.0~4.6）×105 kg。珠江口邻近海域表层TDIAs浓度较高，南海北部陆坡底层由于受到黑潮次表层水影响TDIAs浓度有所升高。夏、秋季南海北部陆坡TDIAs浓度不存在显著性季节差异。夏季南海北部主要受水团混合影响，表现出保守混合行为。珠江口和南海北部TDIAs浓度与世界其他河流以及大洋相比均处于自然水平。

Dissolved inorganic arsenic in the Pearl River Estuary and the northern South China Sea

In order to explore the distributions and influencing factors of total dissolved inorganic arsenic(TDIAs, TDIAs]=As5+]+As3+])in the Pearl River Estuary(PRE)and the northern South China Sea (NSCS), two cruises were carried out in October 2014 and June 2015. The concentrations of TDIAs were measured by Hydride Generation-Atomic Fluorescence Spectrometry (HG-AFS) method. There was no significant difference between the average concentrations of TDIAs of adjacent area of the PRE in summer and autumn (t-test, with significant of level 95%). TDIAs showed non-conservative behavior during the initial mixing of fresh and saline waters in the PRE in both summer and autumn, with scavenging efficiencies of nearly 30%. The transport flux of TDIAs from the PRE to the SCS was (4.0~4.6)×105 kg·a-1. The concentration of TDIAs was higher in the adjacent area of the PRE. The concentration of TDIAs increased at the depth of 100 m in the northern slope of the SCS due to the incursion of the Kuroshio Subsurface Water. There was no significant difference about the average concentrations of TDIAs in the similar area of NSCS between two seasons. TDIAs showed conservative behavior in the NSCS in summer. The distributions of TDIAs in the NSCS is mainly controlled by the mixing of different water masses. Compared with other areas in the world, the concentration of TDIAs remained at natural levels in the PRE and NSCS.