Currently I work on developing tracers, including SF6, SF5CF3, PFTs, C and O isotopes, to quantify the flow and transport of injected CO2 in subsurface geologic formations at the geological storage sites. I have worked on the biogeochemical reactions of shallow aquifers in response to CO2 leak from geological sequestration. The projects include: (1) conducting geophysical logging, pumping test, tracer test, CO2 push-pull experiment and geochemical reactive transport modeling in bedrock aquifers to understand the mineral dissolution and trace element release rates; (2) investigating microbial activities and their impact on trace metal release; (3) carrying out sediment incubation experiments in the lab to investigate the biogeochemical reactions under abiotic and biotic conditions; (4) developing diagnostic monitoring systems to assess the risk of shallow aquifer contamination from CO2 leaking. I have also worked on the hydrogeochemistry, risk assessment and reduction of groundwater contaminations in bedrock aquifers. The completed and ongoing projects include: (1) determine the occurrence and spatial pattern of arsenic contamination and its association with bedrock geology; (2) understand the source and mobilization mechanisms of arsenic in bedrock aquifers from interpretation and statistical analysis on chemistry data; (3) test the feasibility of predicting arsenic contamination in bedrock aquifers using logistic regression models; (4) examine the distribution of arsenic in groundwater, soil, and stream sediment at national, regional to local scales and their associations; (5) investigate the arsenic evolution in individual wells using borehole coring, logging , pumping test, and water sampling with packers; (6) investigate the occurrence, source and mobilization mechanisms of uranium and radon in bedrock aquifers; (7)reduce the arsenic contamination to improve community health in central Maine. I also worked on: (1) development of the strain rate method to estimate the duration of tectonic deformations; (2) studies of the evolution of structural geological systems in Songliao Basin, Hefei Basin, Kuche Basin, China to investigate the enriched zones of oil, natural gas, and CO2.