Spatial and Temporal Variations of Physical-Chemical Water Quality and some Heavy Metals in Water, Sediments and Fish of the Mae Kuang River, Northern Thailand

The present study was conducted to investigate heavy metal (Cd, Pb & Zn) contaminants in water, sediments and fish of the Mae Kuang River, Northern Thailand during July, 2008-June, 2009. It was found that the worst water qualities in dry seasons were caused by low water flow, municipal effluents and industrial discharges. The surface water in the river was classified intoclass 3-4 referring to medium-fairly clean water used for consumption after special water treatment. Pb and Cd in water were below detection limits, while Zn concentrations in water ranged 0.01-0.11 mg L-1. The Pb, Cd and Zn concentrations in sediment were 3.13-27.56, <0.02-0.43 and 3.42-10.32 mg kg-1, respectively. No Cd and Pb residues were found in Henicorhynchus siamensis and Puntioplites proctozysron flesh, while the concentrations of Zn in these fish were 4.57-6.58 mg kg-1. On the other hand, Pb and Cd residues in snakehead fish (Channa striata) were <0.05-2.13 and <0.02-0.24 mg kg-1 wet weight, while the concentrations of Zn in these fish were 3.37-12.19 mg kg-1. This information provides a useful reference inheavy metal contamination in the Mae Kuang River for river management.