Affiliations: Institute for Environment and Development (LESTARI)
Universiti Kebangsaan Malaysia (UKM), Bangi, 43600, Selangor DE, Malaysia | Department of Civil Engineering & Geomatics,
Cyprus University of Technology, Cyprus
Abstract: This investigation quantified spatial variability of heavy metals
and followed methods of the U.S. Environmental Protection Agency (EPA) to
estimate the hazard indices as well as cancer risks associated with consuming
fish caught in the waters of the Langat river basin area, Malaysia. The
calculation of metal pollution index (MPI) was carried out to classify the
study area according to the level of contamination and the order of stations
from highest to lowest MPI values was Langat river > Cempaka lake >
Engineering pond > Pond B > Pond A > Jugra > Bandar. The level of
exposure due to the consumption of each chemical in Tilapia fish tissue was
estimated in an average daily dose equation. The calculated HI ranging from
0.24 to 1.88 indicated 71% stations were in the risk level. Potential
carcinogenic risks associated with the ingestion of heavy metals in Tilapia
fish were evaluated probabilistically by performing 10,000 trials for Monte
Carlo simulation. Cancer risk calculations exceeding the U.S. EPA's acceptable
risk level of 1 in 1,000,000 (or 10^{-6}) included Ni (7.3 ×10^{-4}) and
Cd (2.1 ×10^{-6}). However, the average carcinogenic risk
(2.4 × 10^{-4}) exceeded the accepted risk level to a great extent.
The recommended daily ingestion rate of Tilapia for Malaysian people inhabiting
Langat river basin area was calculated considering 95th percentile TR value of
10^{-6} as an acceptable risk where it is revealed that consumption of
Tilapia should be reduced about 67% from the current level to have an acceptable risk of cancer.
