Despite many good policies and institutions, the coastal environment of Langkawi continues to deteriorate. This could be due to lack of effective governance as well as unregulated waste discharge. Evidences collected from the literature during 1996 to 2013 also revealed a significant increase in the concentrations of Zn (R2 = 0.78) and Pb (R2 = 0.12) in the sediment. This appears to be the result of large volume of terrestrial runoff that brings these metals originating from extensive anthropogenic activities. It is a vital indicator of coastal pollution. It is a matter of concern that in many cases Pb concentration in the sediment exceeded the world average value 20 μg/g as well as Canadian Interim Sediment Quality Standard of 35 μg/g for the coastal areas. Similarly, the metal pollution index (MPI) measured over a period of 2007 to 2009 in fish also indicated an increasing trend of pollution in Langkawi. The maximum MPI value (4.87) was recorded in Spanish mackerel. Since pollution of coastal environment has serious implications for marine biodiversity and health of seafood consumers, measures are required to address this problem. Use of constructed wetland might be effective in reducing the coastal pollution as this will filter the effluent and waste before their mixing with the coastal water. Furthermore, enabling the stakeholders to play the environmental stewardship role will ensure better governance of coastal ecosystem and effective implementation of policies, envisaging an improved monitoring of waste/effluent discharge into the coastal marine environment. These measures are among the actions necessary for achieving a sustainable coastal environment of Langkawi.

Langat River, which is a very important source of drinking water, as well as development in the Langat Basin, needs special care to reduce the pollution. Environmental Quality Report of Department of Environment since 1997 to the latest 2013 addressed that the river possessed the status of class III which required extensive treatment before drinking. However, more than one of the nine water treatment plants in the basin had to remain closed several times during 2012-2015 due to high concentration of chemical pollution in the river. Therefore, the review of secondary literature found out the reasons of chemical pollution in Langat River. The hazardous chemical pollution in the river was mainly due to the anthropogenic activities as well as there was lack of enforcement of policies to reduce the pollution. Hence, a proper and up-to-date chemical using guideline is required for the basin in reducing the water pollution which would be applicable for all the basins in Malaysia.