This paper is the result of environmental geological survey engineering.

Objective As an old industrial base in Northeast China, Shenyang faces potential risks posed by heavy metals in groundwater to the regional ecological environment and human health. Therefore, identifying the pollution characteristics and sources of heavy metals in groundwater is of great significance for the prevention, control and treatment of heavy metal pollution in this region.

Methods A total of 93 groundwater samples were collected in Shenyang, and the concentrations of seven heavy metals were determined. The entropy weight pollution index method was used to assess heavy metal pollution, the potential ecological risk assessment method was applied to evaluate the ecological risks, and the absolute principal component score-multiple linear regression (APCS-MLR) model was used to apportion the pollution sources and their contribution rates.

Results (1) The overall ecological risk of heavy metals in groundwater of Shenyang is slight. Areas with slight ecological risk account for 88.2%, and areas with moderate risk account for 7.5%. Local spot high-risk areas are mainly distributed in the southern industrial-agricultural complex zone. Mercury (Hg), cadmium (Cd) and lead (Pb) contribute relatively highly to the ecological risk. (2) Based on the APCS-MLR model, four mixed pollution sources were identified: (1) Mixed source of industrial activities and traffic emissions; (2) mixed source of agricultural production and domestic sewage; (3) mixed source of agricultural production and urban runoff; (4) mixed source of industrial emissions and agricultural waste. The contribution rates of the four sources are 31.27%, 28.16%, 25.88% and 14.68%, respectively. Heavy metals in groundwater of Shenyang show a spot pollution pattern.Groundwater heavy metals in Shenyang exhibit high-concentration zones of industry-sourced metals (Cd, Pb, Ni, Hg) and agriculture-sourced metals (As, Cu, Zn), which correspond to two pollution mechanisms: “industrial discharge-soil leaching-groundwater contamination” and “agricultural non-point source-irrigation infiltration-subsurface accumulation in groundwater”.

Conclusions The overall risk level is low and controllable. This study can provide technical support for relevant departments to carry out groundwater environmental protection.