Lead, copper, cadmium, zinc contents in stream-waters and sediments from various classes of watershed along the Maeklong river basin [Thailand]
1991
Sopaphan Jiraniratisuai
Correlations of the four heavy metals contents, lead, copper, cadmium and zinc in both stream water and sediment along the Maeklong River Basin with classes of watershed, seasons and type of land usage were studied. Samples from the 15 representative subwatershed covered the area of Tak, Uthai Thani, Kamphaeng Phet, Suphan Buri, Kanchanaburi, Nakhon Pathom, Ratchaburi, Samut Sakhon and Samut Songkhram provinces. Contents of lead and cadmium in both stream water and sediment were not significantly different among the five various classes of watershed while copper and zinc contents varied. The highest contents were found in the fifth class of watershed in both stream water and sediment. The average concentrations of lead, copper, cadmium and zinc in stream water were 6.78, 21.46, 0.66, 70.26 g/l and those found in sediment are 7.78, 16.04, 0.43 and 62.14 g/g respectively. Besides those, the average contents in water of the four metals were highest in rainy season and in sediment, lead and zinc contents were highest in summer while copper and cadmium in rainy season and winter. The contents of metal corresponded to the types of land usage, the metal content in non-forest area were higher than in forest area. Major factors influencing the contents of metals in water and sediment were geological, land usage and human activities. However, the contents of the four metals of Maeklong River Basin do not exceed maximum permissible level in surface water of NEB standard and are not relatively higher than the watershed in other region, major river of Thailand.
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