Investigation of Pb dispersal and accumulation around untreated former tin mines in Perak, Malaysia

摘要

There are approximately 114 000 ha of former mining area left derelict after the tin mining industry collapsed in Malaysia [1] These lands are currently turned into agriculture and aquaculture farms. Unfortunately, studies have indicated that crops cultivated on tin tailings have been found to contain alarming levels of Potentially Toxic Elements (PTEs). Fish that are bred in slurry ponds and mine pools are also not excluded from PTEs. This research aims to determine and identify the atmospheric dispersal as well as the accumulation of Pb from active and derelict former tin mines in Perak, Malaysia. Samples of plants; Melastoma sp. and Benincasa sp. and fish; Tilapia sp. and Cichla sp. grown and bred in mining ponds were collected from active farms in Location 1 and 2. Plants and fish of the same species and grown naturally were also taken from abandoned mine sites at Location 3 and 4. Atmospheric dispersal of heavy metals is also investigated using available biomarkers. Tree bark from Acacia mangium sp. is collected to represent heavy metal dispersal from wind erosion of tin tailings from the mine sites. The methodology for sample analysis was done by using wet digestion analysis with nitric acid and hydrochloric acid. Concentration of heavy metals was determined using flame atomic absorption spectrometry (FAAS). Pb concentration was found to be highest in the root of Melastoma sp. at 57.62 mg/kg and in the muscle of Cichla sp. at 27.28 mg/kg. The results indicate elevated Pb levels regardless of whether it is from active or abandoned tin mine site. Heavy metal levels in all of the plants and fish samples in this study were found to be above the safe limit issued in the Food Acts 1983 and Regulations 1985[2][14]. Appropriate measures should be taken to further reduce the dispersal and exposure of heavy metals from the former mine sites from entering into the food chain and causing serious threat towards health and safety.