SURVEY ON THE ENVIRONMENTAL DISTRIBUTION OF HERBICIDE PARAQUAT AND ITS REGULATORY RELEVANCE TO AGRICULTURAL SUSTAINABILITY: A CASE STUDY IN TAIWAN

摘要

Paraquat (l,I'-dimethyl-4,4'-dipyridinium chloride) is frequently used as a quaternary ammonium herbicide because of its excellent action within plant cells in the crop protection and horticultural use. From the ecotoxi-cological, human health and regulatory points of view, it is urgent to restrict the release of the highly acute chemical into the environment from agricultural applications. In this study, emphasis was put on the up-to-date survey on the sale amounts of main herbicides (including paraquat) in Taiwan, and the residual status of paraquat in the aquatic ecosystems. It showed that the sale amounts of main herbicides in Taiwan significantly decreased from 12,289 metric tons in 2009 to 10,451 metric tons in 2010. In parallel with the decline, the demand for paraquat abruptly decreased from 2,105 metric tons in 2009 to 1,245 metric tons in 2010. On the other hand, the regulatory frameworks of protecting human health, food security and water quality resulting from the use of paraquat have been described to be a case study because it is one of the most widely used herbicide in Taiwan. The significant progress is that the residual paraquat has notably declined in the past two decades, which was in accordance with the enhancement of pesticide regulation and decrease of paraquat usage rate. Finally, some recommendations for the pollution prevention and toxicity reduction of pesticides (including paraquat) were also addressed to make efforts towards a sustainable society.