TITLE: POLYCYCLIC AROMATIC HYDROCARBON (PAHS) AS A MOLECULAR TRACER OF LEACHATE POLLUTION IN LANGAT RIVER.

Introduction The important aims of environmental quality studies is to investigate the present of anthropogenic compounds such as organic micropollutants on the ecosystem, in order to minimize or prevent adverse effects. Polycyclic Aromatic Hydrocarbon (PAHs) is made up of large group of compound but semi volatile. There are 16 semi-volatile PAHs classified as priority pollutants by USEPA some of which have been shown to disrupt endrocrine system in human. Most of PAHs are come from anthropogenic activities that held by human activities. Besides that, the different intrinsic physicochemical properties of organic contaminants, they tend to interact to different extent with suspended particulate matter (SPM), bed sediments and biota. Direct discharge of leachates to river will enhance the transport of organic contaminants such as PAHs to the coastal environments and open oceans. Leachate is the liquid that drains or 'leaches' from a landfill it varies widely in composition regarding the age of the landfill and the type of waste that it contains. Landfill leachates are generated by excess rainwater percolating through the waste layers in a landfill. The risks from waste leachate are due to its high organic contaminant concentrations and high ammoniacal nitrogen. Leachate streams running directly into the aquatic environment have both an acute and chronic impact on the environment which may be very severe and can severely diminish bio-diversity and greatly reduce populations of sensitive species. Where toxic metals and organics are present this can lead to chronic toxin accumulation in both local and far distant populations. The burial of municipal solid waste in landfills is the most common disposal alternative in most countries. Land filling and depositing of solid wastes in open dumps have been the most common methods for the disposal of municipal solid wastes in Malaysia. Usually, landfill sites in Malaysia are situated near major towns or rivers.