The EPA program results of “Control and Investigation Program for National Agricultural Land with High Potential of Heavy Metal” in 2010 established “the system for potential assessment and early warning control of heavy metal contamination of agricultural land” and “ the mechanism for screening process of the heavy metal contamination of agricultural land”. According to the results, there were about 2.65% of agricultural lands (15,000 hectares) in Taiwan reaching hazardous levels that require urgent investigation and remediation. In order to speed up the pollution control regulation and actions, EPA continued to implement the second-phase Control and Investigation Program for National Agricultural Land with High Potential of Heavy Metal (abbreviated as “2nd Control and Investigation Program”). The aim of the “2nd Control and Investigation Program” was to establish the national control regulation strategies of agricultural lands with high potential of heavy metal by revising the mechanism for pollution screening process and building the management systems. It needed to prioritize investigation areas and develop early tools of decision support system for the foundation of the following control strategy. Moreover, there were several regional investigations conducted as the following: the environmental survey and additional chromium (total Cr and Cr (VI)) soil survey of agricultural lands for four groups of the irrigation association in Taoyuan, and expanded soil survey of agricultural lands in the township of Chunghwa Hemei. Combining actual survey practices and pollution control requirements in agricultural lands, the investigations provided feedback to the screening process and operational procedures to establish consistency standard processes. Eventually soil investigation and remediation manuals of heavy metal pollution in agriculture land were compiled as reference for associated practitioners in this specialized area. In the four groups of the irrigation association in Taoyuan, the total amount of 1,130 soil samples and 60 sediment samples were collected and 3 automatic water quality monitoring devices were set in Sinjiesi River. The results showed that there were 354 soil samples (over-limit ratio: 31.3%, 45.5 hectares) and the concentrations of copper (Cu), Zinc (Zn) and chromium (Cr) in 40 sediment samples were over control standards. However, there were no obvious abnormal readings in the result of automatic water quality monitoring. In addition, there were 44 hectares of agricultural lands exceeding soil control standards in the survey results in the township of Chunghwa Hemei. This part of investigation was divided to two stages. In the 1st and 2nd stages, the agricultural lands exceeding soil control standards were found in 29 out of 34 samples and in 223 out of 398 samples respectively, where target compounds were Ni, Cr, Cu and Zn. The concentrations of cadmium (Cd) in 6 soil samples were found over the limit in the 2nd stage.

Pollution screening process, High potential pollution agricultural land, Heavy metals of soil