广州市流溪河水体中6种内分泌干扰素时空分布特征与环境风险

Spatio-Temporal Patterns and Environmental Risk of Endocrine Disrupting Chemicals in the Liuxi River

以雌酮(E1)、雌二醇(E2)、双酚A(BPA)、壬基酚(4-NP)、辛基酚(4-t-OP)和三氯生(TCS)这6种内分泌干扰物(endocrine disrupting chemicals,EDCs)为对象,研究其在广州市流溪河水体中的时空分布特征,并对其雌激素活性进行风险评价.结果表明,14个监测点均有EDCs检出,总范围在26.07~7 109.5 ng·L-1,以4-NP贡献最高(78.62%),其次为BPA(11.91%),其他4种目标物浓度均较低(≤4.92%).时空变化上,EDCs浓度从上游至下游逐渐增加,尤其是下游支流中EDC浓度偏高;丰水期4-NP、4-t-OP浓度显著高于枯水期(P<0.05),而E1、E2、BPA则呈相反趋势.相关性分析显示,DO与6种EDCs浓度变化呈显著负相关,高锰酸盐指数、EC、TN、TP、NH+4-N与E1、E2、BPA、TCS呈显著正相关,而与4-NP相关性不显著(P>0.05),说明E1、E2、BPA、TCS可能与氮、磷营养盐污染同源.冗余分析(redundancy analysis,RDA)显示,流溪河水体中EDCs的季节性变化比空间变化更为明显(RDA1 56.14%>RDA2 14.20%),丰水期水体中EDCs浓度变化主要受4-NP影响,而枯水期则主要受BPA影响.与世界范围内水体中EDCs浓度相比,流溪河中下游河段4-NP、BPA和TCS浓度处于较高水平,其他3种目标物处于中低水平.风险评价结果显示,流溪河中下游河段风险熵值RQ值均大于1,说明该区域具有高雌激素活性风险.

This study aimed to investigate the occurrence and spatio-temporal distribution of 4-tert-octylphenol（4-t-OP）,4-nonylphenol（4-NP）,triclosan（TCS）,estrone（E1）,17β-estradiol（E2）,and bisphenol-A（BPA） as endocrine disrupting chemicals（EDCs） in the water of the Liuxi River and to evaluate the risks for estrogenic activity. The results showed that EDCs had been detected at the 14 monitoring sites and the total concentration ranged from 26. 07 ng·L^-1 to 7109. 5 ng·L^-1,with the highest contribution rate coming from 4-NP（78. 62%）,followed by BPA（11. 91%）,and the other four EDCs（≤4. 92%）. On a spatial and temporal scale,the EDC contents increased longitudinally from upstream to downstream,especially in the heavily-polluted Baiyun section where the water quality was lower than level Ⅴ. The EDC contents in the tributaries were much higher than those in the main channels. Influenced by the monsoon precipitation,the contents of 4-NP,4-t-OP,and total EDCs in the rainy season were significantly（P〈0. 05） higher than those in the dry season,while the seasonal changes of E1 and E2 followed the opposite tendency. A Pearson correlation analysis showed that DO was significantly negatively correlated with all the EDCs,suggesting that the EDCs and reductive organic pollutants might coexist. As TN,TP,NH＋4-N,permanganate index,and EC were significantly positively correlated with E1,E2,BPA,and TCS but not obviously correlated with 4-NP（P〉0. 05）,we presumed that the pollution source of E1,E2,BPA,and TCS might be the same with nitrogen and phosphorus nutrition,originating from the point source emission of the domestic sewage,industrial,and agricultural wastewater. In contrast,4-NP and 4-t-OP more likely originated from the non-point source pollution fromagriculture. RDA results showed that the variation of the EDCs contents by season was more obvious than that in space（RDA156. 14% RDA2 14. 20%）,which was much more influenced by 4-NP in the rainy season and by BPA in the dry season. As E1,E2,and TCS were positively correlated with the Cu,Zn,cyanide,and fecal coliform,these three target compounds could be used to indicate the multiple pollution components for water quality. Compared with the worldwide reported EDC contents in waters,4-NP,BPA,and TCS contents in the middle and lower reaches of the Liuxi River were at higher levels,while E1,E2,and 4-t-OP were at the middle and lower levels. The risk assessment for estrogenic activity showed that the RQ values in the middle and lower reaches of the Liuxi River were all greater than 1,indicating that the downstream river sections were under high risk for estrogenic activity. As a result,appropriate precautions are needed to improve environmental management.