Abstract: Owing to the concealment and retardation of groundwater contamination,especially for the petrochemical projects with the pollution characteristics as multi-type,high environmental risk,illegible protect-object,the assessment of original groundwater environment is important. Based on the analysis of the large-scale petrochemical project on the littoral zone of the Pearl River Delta,this paper gives the exploratory-discussion of the determination of the protect-object and assessing standard of gro...