Pollution Characteristics and Health Risk Assessment of Volatile Organic Compounds (VOCs) and Semi-volatile Organic Compounds (SVOCs) in Qiantang River's Hangzhou Section During a Water Odor Pollution Event

Abstract

For surface water samples collected from the Hangzhou section of Qiantang River (before, during, or after the occurrence of a water odor pollution event), 125 kinds of volatile organic compounds (VOCs) and semi-volatile organic compounds (SVOCs)were quantitatively determined via purge&trap-gas chromatography-mass spectrometry and liquid-liquid extraction-gas chromatography-triple quadrupole mass spectrometry. Then, the pollution characteristics of the VOCs and SVOCs were analyzed, and the health risk of these compounds was assessed. The results showed that 17 VOCs and SVOCs in the surface water samples of 4 monitoring sections were detected, in a concentration range of 0.01-1.21 μg·L-1, which is a low pollution level. The concentration of dichloromethane was the highest of 17 VOCs and SVOCs, accounting for 36.3%, and it was thus clear that dichloromethane was the main contributing factor. During the water odor pollution event, the concentrations of VOCs and SVOCs were significantly higher than they were in the three months before or after the occurrence of the event, by 2.1-4.6 times, reflecting the strong external source input. In addition, human health risk assessment of ingestion through drinking water and absorption through skin contact was performed using US EPA recommended methods. It indicated that the total non-carcinogenic and total carcinogenic risks (∑HI and ∑R) caused by VOCs and SVOCs are 2.4×10-3-3.6×10-2 and 1.9×10-7-1.0×10-6, respectively, both of which belong to the acceptable risk level. Therefore, although ∑HI and ∑R during the occurrence of the odor event were significantly higher than those in the three months before or after the event, the VOCs and SVOCs detected will not cause obvious non-carcinogenic nor carcinogenic health effects on humans.