Suggestions for plant parameters to monitor potential CO2 leakage from carbon capture and storage (CCS) sites

Potential CO2 leakage from carbon capture and storage (CCS) facilities should be monitored and managed carefully. Biomonitoring technologies for CO2 leakage using plants could be very effective, especially in areas near transport pipelines, because of the extensive areas that they can cover. A greenhouse study was conducted to investigate whether early changes in plant parameters could be an effective indicator to detect leaked CO2. Corn (Zea mays), which was reported to be a CO2‐tolerant species, was selected to identify specific indicators of CO2 leakage. The mean soil CO2 concentration for soil treated with CO2 was 20–40%, which is similar to the concentration that could occur near transport pipelines through slow‐insidious seepage. In the soil treated with CO2, the number of yellow leaves at the canopy level was significantly increased from the sixth day of CO2 injection compared to the control. The chlorophyll content in green leaves was significantly reduced on the eighth day from CO2 injection. The soil water content in the treated soil was increased from the sixth day of injection due to reduced root adsorption. The results of this study implied that early changes in parameters of CO2‐tolerant species such as canopy‐level discoloration and chlorophyll content could be used as CO2‐specific indicators for the detection of soil CO2 leakage. We suggested that canopy‐level monitoring is a promising, useful technique for soil CO2 leakage in extensive areas, such as near CO2 transport pipelines. In addition, rhizosphere‐level parameters, such as soil water content, could be good subsidiary indicators together with the large‐scale collection of baseline data and statistical analysis. © 2019 Society of Chemical Industry and John Wiley & Sons, Ltd.