Contamination characteristics and causes of volatile organic compounds in the groundwater at a petrochemical contaminated site

Volatile organic contaminants (VOCs) pollution in the groundwater of a petrochemical contaminated site in a city of northwestern China was investigated. The results show that VOCs were detected in all groundwater samples, the most frequent detected VOCs are chlorinated hydrocarbons (CHCs) and BTEX. The detection rate of CHCs and BTEX are 60% and 40%, respectively. The concentration of Benzene and 1,2-Dichloropropene exceeds the standard of drinking-water, and thair over－standard rate is 30% and 10%, respectively. The maximum concentration of Benzene is 1515 μg/L, which exceeds the standard of drinkingwater over 150 times. VOCs which released from the crude oil tank and wastewater treating pool are important sources of VOCs in groundwater in the contaminative fields. Factors affecting the VOCs concentrations of groundwater in the study area include the chemical and physicochemical properties of VOCs and high vulnerability of groundwater in this site.