Abstract:
This research was focused on distribution of cadmium in stream sediment and suspended solids from Huai Mae Tao and Huai Mae Ku creeks in Mae Sot District, Tak Province. The surrounding areas have been found cadmium contamination in paddy field and rice grain, besides cadmium was also detected in blood of local villagers. Moreover, the local economic is also threaten because rice cultivation had been prohibited by the government policy; consequently, compensation of hundreds million baht per year has to be paid to the farmers. Twenty eight stream sediment and eleven suspended solids samples with surrounding water samples were collected from Huai Mae Tao, Huai Mae Ku and Huai Nong Khieo (control site), before all samples were analyzed using ICP-OES for total cadmium and zinc concentrations. In addition, significant fractions of cadmium and zinc in stream sediment samples were determined using BCR Three-step; these fraction would give better idea to indicate potential cadmium impacting directly to the environment and human health. Analytical results show that soluble cadmium contents in all water samples are lower than the detection limit. Huai Mae Tao creek which is directly influenced by mining activities obtained the highest total cadmium and zinc concentrations in both stream sediment and suspended solids while Huai Nong Khieo creek yielded the lowest concentrations. Regarding sequential analyses, cadmiums in stream sediments from Huai Mae Tao contain mostly extractable forms (BRC1 and BRC2) which are very easily transferred into living organism; on the other hand, those from Huai Mae Ku are significantly characterized by BCR2 and final residual and those from Huai Nong Khieo are mainly in final residual form. It seems likely that sediments from Huai Mae Tao have more potential to effect the environment. In conclusion, Huai Mae Tao creek, closely related to zinc deposit, consequently contains high levels of total cadmium and zinc by natural processes (e.g. erosion and weathering) that are actually risky to agriculture, besides human activities may activate cadmium accumulation in the area. Apart form mining activity, agricultural processes would be taken into consideration for further discussion and subsequently protection and remediation plans. Eventually, it would lead to sustainable management of mineral resource and environment.
