Analysis of heavy metal contents in streamwater and sediment of various land use patterns at Kok-Ma Watershed Research Station (KWRS) and the Royal Watershed Development Project unit 1 (Tung Jaw), Chiangmai [Thailand]
1983
Kasem Chunkao | Sittichai Tantanasarit | Wicha Niyom (Kasetsart Univ., Bangkok (Thailand). Faculty of Forestry. Dept. of Conservattion)
Average annual quantities of lead, mercury and cadmium in human settlement area shown in stream water are 20.30, 0.12 and 4.99 microg/l and in sediment are 4.54 mg/kg, 19.94 microg/kg and 1.83 mg/kg, respectively. In agricultural area, the concentrations in stream water are 15.87, 0.09 and 3.25 mug/l and in sediment are 6.75 mg/kg, 21.33 microg/kg and 2.38 mg/kg, respectively. In reforestation, the concentrations in stream water are 12.78, 0.08 and 5.16 microg/l and in sediment are 2.58 mg/kg, 58.68 mug/kg and 0.56 mg/kg, respectively. In hill evergreen forest, the concentrations in stream water are 13.53, 0.06 and 4.26 microg/l and in sediment are 2.11 mg/kg, 90.56 microg/kg and 0.55 mg/kg, respectively. Quantities of those 3 heavy metals both in stream water and sediment from human settlement area agricultural area and reforestation area at Tung Jaw comparing with the hill evergreen forest area which is the controlling area, are slightly different. This may result from irregular changes in areas owing to anthropogenic activities and variation in water flows in the mountains. Quantities of the metals in stream water from the 3 mentioned areas are lower than of the standard values for drinking water as set by World Health Organization. For sediment, when compared with those from rivers in Thailand, the quantities of the three metals are also lower.
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