These metals are considered the most important
form of pollution of the aquatic environment because of their
toxicity and accumulation by marine organisms; and also because
of their persistent and being not easily biodegradable in nature.
Metal pollution of the sea is less visible and direct than other types
of marine pollution but its effects on marine ecosystems and
humans are intense and very extensive Effluent discharges by industry,
atmospheric depositions and occasional accidental spills of
toxic chemicals are some of the major sources of pollution of the
aquatic environment. Apart from threat from polluted environment,
canned fish is subjected to lead contamination during
canning process. Solder used in manufacture of cans has been recognized
as a source of lead contamination during canning