The National Oil Spills
Detection and Response Agency (NOSDRA) on Thursday said findings on the dead
fishes littering the Atlantic coastline indicated high levels of toxicity
caused by toxic wastes discharge.
The agency noted that the
discharge of toxic materials into the Atlantic may have come from land as the
wastes from domestic and industrial sources often empties into the water body.
NOSDRA had on April 22 said
it was coordinating a multi-agency investigation, aimed at unraveling the cause
of the reported massive death of fishes within the nation’s territorial waters.
Mr Idris Musa,
Director-General of NOSDRA in a statement said that the high toxicity of the
dead fishes and water samples was caused by pollution from heavy metals from
industrial and domestic wastes.
He said that relevant
government agencies which have mandates on the marine environment collaborated
with NOSDRA on the study.
Musa listed the Nigerian
Maritime Administration and Safety Agency (NIMASA), Nigerian Institute of Oceanography
and Marine Research (NIOMR), National Environmental Standards and Regulations
Enforcement Agency (NESREA).
He said the Federal Institute
for Fisheries Research was amongst the establishments enlisted in the efforts
to unravel the likely causes of the massive death of the fishes.
According to Musa, results
of the tests conducted confirmed its preliminary findings that the death of the
fishes were not linked to oil leakages as the levels of hydrocarbon in the
samples tested were within regulatory limits.
“The results of the
laboratory tests were perused, and we make explanation on the parameters of
concerns that were analysed for the purpose of clarity and understanding.
“As earlier mentioned, the
findings did not show hydrocarbons (Oil) as the possible cause of the death of
the fishes.
“In the course of the anaiyses,
Total Petroleum Hydrocarbons (TPH), Polycyclic Aromatic Hydrocarbon (PAR),
Benzene, Toluene Ethylene and Xylene (BTEX) were within regulatory standard
limits in water, sediments and fish tissue analyses.
“However, there were some heavy
metals such as Cadmium, Chromium Copper, Zinc and Iron that exceeded regulatory
standard limits in the coastlines of the
three states, Delta, Bayelsa
and Rivers.
.
“In the water samples taken at
the coastline in Bayelsa State, the values of Cadmium and Iron were higher than
the regulatory standards limit.
“The Cadmium in the water was
between 0.001 and 0.173 miligramme per litre (mg/l) with an average value
of 0.064 mg/l. This is above the regulatory limit of 0.05 mg/l as well as the
control sample value of 0.08 mg/l.
“Similarly, the value of the
iron content in water in the area ranged between
1.914 - 3.408 mg/l with a mean
value of 2.503 mg/l. This is above the regulatory limit of 1.00 mg/l.
“The values of the parameters
in sediments were substantially within regulatory limits. The values of
Chromium and copper in the sampled dead fishes' tissue were slightly higher
than the European Union ( EU ) Standards limits,” Nusa stated.
The NOSDRA D-G noted that haven
ruled out oil pollution as cause for the dead fishes, the plausible causes
could partially be attributable to other human related pollution activities
which are probably land based.
“In this case, while it is
commonly observed that most industrial and domestic wastes which contain heavy
metals such as cadmium, iron, zinc, copper found their ways into drainages and
onward transfer to the water bodies.
“Their deleterious impact may
be negative to aquatic species, other mammals and human beings. The main
sources of these are batteries, galvanised pipes, fertilisers, sewage sludge
and plastics.
“Such may be the case in the
analyses of dead fishes found at the coastline in Delta and Bayelsa where
chromium was found in fish tissue.
“Copper was also found in the
fish tissue sampled in Delta State but not in those of Bayelsa and Rivers
State.
“Furthermore, a sudden release
of heavy metals is not likely to kill fishes except those trapped at the point
of release because, cadmium in particular is highly toxic.
“Long term accumulation
(chronic) rather than short term (acute) heavy metals could cause the death of
fishes. It is also curious that a specific species of fish is allegedly involved
in the circumstance under consideration,” Musa said.
He recommended that the country
should pay more attention to the activities of those illegally carrying out
fishing in our territorial waters to guard against possible dumping of wastes
as well as unwanted aquatic species.
.
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