Spatial distribution of mercury pollution in the Mempawah River Watershed, West Kalimantan – Indonesia

Abstract

Mempawah River Basin (DAS) is a water resource for the people of Mempawah and Landak Regencies. The community uses the Mempawah River as the main medium for agricultural needs, plantations, and the rearing of fish for consumption. Awareness of health that comes from water with its various uses, there has been consumer anxiety when consuming air along with agricultural and fishery products that are relevant to water use in the Mempawah watershed. This phenomenon occurs because the water resources of this watershed area have been polluted by mercury as a result of unlicensed gold mining activities in its spatial extent. This research was conducted to analyze the level of mercury pollution in the river basin, due to illegal gold mining activities. The method applied was purposive sampling, through 29 water sample points located in the upstream, middle and downstream. The sample results were explained using the Atomic Absorption Spectroscopy (AAS) tool. Then, from a spatial perspective, the location of PETI activities was analyzed spatially using Spatial Dynamic Modeling Geographical Information System software with kriging interpolation techniques, to predict the distribution of mercury pollution. The results of the research show that in the middle part of the Mempawah watershed, there is mercury pollution from 0.0023mg/lt to 0.0083 mg/l and has exceeded the threshold determined by PP No. 22 of 2021. The upstream and downstream parts of the Mempawah watershed are not polluted by mercury, because the PETI activity point is only in the middle part of the Mempawah watershed. These findings provide suggestions that the allocation of Mempawah River water as the sole raw material for corporate entities and its use for growing fish communities should be more closely monitored, to avoid danger, due to the chain of heavy metal contamination in the form of Mercury.