Abstract:
Due to anthropogenic activities heavy metals in the environment tend to reach
concentrations which are not permissible, causing adverse health conditions. These
elements enter into the human body through dermal, inhalation, and ingestion
pathways and may create carcinogenic, mutagenic and teratogenic toxic effects. Due
to their ubiquitous nature, persistence and nonbiodegradability, and Toxicity in
humans, and due to over exposure to heavy metals results in bioaccumulation and
bio-magnification along food chains and ultimately lead to destruction of organisms
and ecological systems. Excessive heavy metal accumulation in agricultural soils may
lead not only in soil contamination but also affect food quality. Therefore, this review
was done to identify the heavy metal accumulation on three selected samples of the
Asian countries: Sri Lanka (Colombo city dust), China (Dongting Lake) and India
(Pondicherry) in order to derive basic understanding on the heavy metal
accumulation. Research articles (132) were initially collected based on carcinogenic
heavy metals in sediment. Colombo city dust has recorded the highest accumulation
for Zn (339 mg/kg) and Cu (173.5 mg/kg) in Sri Lankan sediment samples. Then, two
Asian countries India and China were selected based on the high rate of anthropogenic
activities. However, depending on the sample location the heavy metal accumulations
may vary. Hence, the evaluation is done to compare the heavy metal composition on
the three sample sites. Pondicherry has recorded as having the highest Cr (334 mg/kg)
accumulation in sediment samples, Ganges River in India was reported as having high Ni (48 mg/kg) content while the Dongting lake in China recorded as having the highest
concentrations of Zn (322.6 mg/kg), and Pb (57.96 mg/kg). In conclusion,
accumulation of heavy metals among the three sediment samples, Colombo city dust
in Sri Lanka is reported as the highest while the second highest is reported at Dongting
Lake in China, and third highest at Pondicherry, India.
