Health risk assessment for heavy metals in Chao Phraya River basin

Abstract

Heavy metal contamination has become a serious concern due to its toxicity not only on ecosystems but also directly on human health. The Chao Phraya River Basin is the main area important for commerce, industries, and residence in Thailand. This study aimed to evaluate the impact on human health due to heavy metal contamination and identify the relationship between land use and heavy metal contamination in the Chao Phraya River. Pearson correlation was applied to analyze the relationship between heavy metal concentration and water parameters. The results indicated that during 2009-2013, Fe concentration positively correlated to turbidity (0.640), total phosphate (0.622), suspended solids (0.542), and Ni level (0.513) in the river but negatively correlated to Zn level (-0.517) at P<0.01. From 2014 to 2018, the results revealed that Fe concentration positively correlated to turbidity (0.900), suspended solids (0.671), Mn (0.607), and Ni level (0.512) at P<0.01, and Cd concentration also positively correlated to Cr level (0.509). The results showed that human health risks in some stations in Lampang, Chiang Mai, and Sukhothai province were acceptable from 2009 to 2011 and changed to very high risk on human health from 2015 to 2018. The heavy metal pollution index was calculated and compared to land use data. The results revealed that the change from deforestation into agricultural land, especially in the Yom River area, could be the cause of the heavy metal contamination by fertilizer. All of the data was created to map for easy understanding.