Taiwan Environmental Protection Administration (EPA) has conducted investigation of farmlands with high heavy metal contamination potential from 2010 to 2017. In addition, the policy of farmland pollution prevention and management was also implemented by EPA in 2018. According to the survey of farmland pollution, farmlands were contaminated with low-concentration heavy metal through irrigation water over long periods of time. Moreover, factories in industrial and agricultural mixed areas illegally discharge large amounts of waste water, which contain high-concentration heavy metal, into unknown ditches and road gutter at last contaminate the irrigation water and farmlands.
In order to establish the long-term effective precaution and prevention procedures to avoid heavy metal pollution in farmlands, the “Development Project of Quantitative Assessment Tool for Prevention of Heavy Metals Pollution in Farmland” is progressed. The project utilizes water quality simulation to establish transmission model of heavy metals pollutants from the water source through the irrigation system to the farmland, as a tool for traceability analysis and impact assessment of irrigation canal pollution.
Water quality simulation objects of the project are “Taichung Zhancuoyuan irrigation system” and “Changhua Xin irrigation system”. Water quality simulation results can evaluate the changes in the concentration of heavy metals in each section under different input conditions. By scenario simulation, it is estimated how many years the farmland has reached the pollution control standard under the situation of irrigation water being polluted by the source or intervention.
Further, the project assesses the implementation effect of “Irrigation water quality protection program” and “Conservative heavy metals total discharge schemes”. The project simultaneously conducts soil and related agricultural materials surveys, cooperating with the crop monitoring of the Council of Agriculture, clarifying the transmission pathways and potential sources of pollution to farmlands.