Nitrate Pollution Distribution and Source Identification in an Alluvial Aquifer

摘要

Characteristics and spatial distribution of nitrate concentration and its isotopic composition were used for identifying pollution mechanisms and sources in groundwater. An aquifer downstream of Dagu River in Jiaozhou city was taken as an example which was seriously contaminated with nitrates. The results showed that the study area could be divided into 4 divisions. Division A planted many kinds of vegetables with high nitrate contents and low δ~(15)N ratios. High values of concentrations and δ~(15)N ratios were appeared in Division B which mainly grew Chinese cabbage. Low nitrate concentrations were observed in Division C, whereas the wide range of δ~(15)N values may reflect the contribution of both natural and anthropogenic sources. Groundwater nitrate at Division D were mainly affected by surface water.