Abstract:
Environmental pollution due to landfill leachate has given rise to a number
of studies in recent years. Heavy metals are a source of environmental
pollution affecting the aquatic and terrestrial ecosystems. Main sources of
heavy metal pollution are industrial waste, domestic sewage and landfills.
Landfill sites are one of the major sources of heavy metal pollution which
affect the soil and water around it. Various types of wastes such as waste
food cans and scrap metal and the indiscriminate dumping of household
hazardous waste and electronic waste such as batteries and electronic
apparatus generate heavy metals in a landfill. The release of heavy metal
into the adjacent environment is a serious environmental concern and a
threat to public health and safety. It is important to identify whether there is
any risk of contaminating the environment due to heavy metals by landfill
leachate. Therefore, the objective of this research had been to determine the
risk of soil pollution by heavy metals in landfill leachate produced by one of
the municipal solid waste collecting sites in Weligama, Sri Lanka. Soil
samples from the landfill site and water samples from a nearby stream were
collected, digested with conc.HNO3 and analyzed for heavy metals such as
Zn, Pb, and Ni by Atomic Absorption Spectrophotometry (AAS). Zn, Pb,
and Ni were detected to be (in ppm) 74.5, 52.8, and 94.2 in the cultivated
land and 101.8, 54.7, and 80.8 in the landfill site respectively. It is possible
to conclude that there are no any harmful impacts from this Weligama
landfill site as far as the three heavy metals involved in this study are
concerned. However, Ni content in the cultivated land is higher than that in
landfill site and also higher in some collection points than the regulatory
standards of heavy metals in agricultural soil. A possible Pb contamination
was indicated in some water samples as its concentration in some points
was detected to be as high as 0.05 ppm.