Mercury rising in seafood!

C Shivakumar
Chennai:

Beware! The fish you consume could be laced with mercury, cadmium,
arsenic and other heavy metals posing a threat to your health.

A study conducted on Ennore Creek by National Institute of Ocean
Technology has revealed that there is high level of heavy metals in
marine environment due to industrial and man-made pollution.

The Waste Load Allocation (WLA) and Waste Assimilation Capacity (WAC)
assessments carried out by Earth System Science Organisation
(ESSO)-National Institute of Ocean Technology (NIOT) indicates that
the creek receives waste water from numerous sources including sewered
and unsewered areas from the adjoining power station and fertilizer
units and these excess release of heavy metal and due to the lack of
minimum flow in the creek restrict the dilution of such toxic minerals
in the creek, Atmanand told Express.

And this has been causing a threat to the marine ecosystem. “This
could lead to ecosystem and food chain contamination,” a study ‘Heavy
Metal Concentration of Sea Water and Marine Organisms in Ennore Creek,
Southeast Coast of India’ revealed.



The study was done by scientist M Jaikumar of Aquaculture Foundation
of India and it was published in The Journal of Toxicology and Health.

Jaikumar says that the study was conducted to determine heavy metals
concentrations in water and commercially important marine organisms
from Ennore Creek since they are important component of human diet.

The study revealed that grey mullet or Madavai or kayal meen in local
parlance has highest zinc concentration in the edible part while
sardine had cadmium which was greater than the Food and Agriculture
Organisation (FAO) limits.

What is more surprising that shrimps in the creek, a local favourite
and also known as jalebi, vastly consumed flat head grey mullet, mathi
pacchai  and Therapon Jarbua have highest concentration of mercury.

Jaikumar says that liver and kidneys of fish and shellfish tend to
concentrate environmental mercury. He says that marine organisms
possess a remarkable capacity to turn inorganic mercury into organic
compounds thus rendering mercury more easily transferable throughout
the aquatic food chain.


“Marine organisms contain mercury in levels up to 5 milligram per
kilogram and fish consumption may constitute an important source of
mercury exposure for health,” the study revealed.



Interestingly, the shrimps and other marine organisms found in Ennore
Creek also have high level of arsenic.

Jaikumar says the pollution of Ennore Creek is due to failure of
enforcing the laws to protect the marine environment. He warns that
the activities at the upper-course of the Ennore Creek should be kept
under strict surveillance as they are capable of increasing the heavy
metals discharge into the creek.

Interestingly, as per The Monitoring of Marine Pollution through
Coastal Ocean Monitoring and Prediction System (COMAPS) Programme, the
total wastewater released by industries other than power plants is
28000 cubic metre/day. The two thermal power plants in the area
discharge about 100,000 cubic metre of coolant water into the sea
through the Ennore creek. The Ennore coastal waters are also recipient
of untreated sewage through marine outfall close to the shore.

Ennore has two Thermal power plants - North Chennai Thermal Power
Station and Ennore Thermal Power Station both of them drawing coolant
water from the creek. Manali industrial complex and the Kamarajar Port
are located in the northern section of the creek.The Buckingham Canal
stretches as the Ennore creek in the north to Cooum River in the south
and further southwards from thereon. Several discharges enter this
stretch of the Buckingham Canal from industrial sites such as Madras
Refineries Ltd, (MRL) and Indian Oil Corporation. Municipal discharges
also enter Ennore creek through a number of drains from the north
Chennai area.

Atmanand says the beauty of the creek lies with its broad clean sea
water flow with thick mangrove vegetation in its bank.

“Periodic sludge removal from inner creek and the assurance of minimum
flow will bring back its original glory. However, even if all the
present waste water released into the creek are collected and treated
with disinfectant alone will not remove the excess nutrient load and
thereby the risk of eutrophication from the current level,” he said.

“We would like to remind our previous suggestion to divert the waste
water entering to the creek through Buckingham Canal or directly to be
collected separately and discharged after primary treatment and
disinfection directly into the marine outfall located at a15 metre
depth,” he says.



Meenavar Makkal Munnani president J Kosimani admitted that heavy
metals in the polluted waters of Ennore Creek does pose a threat to
marine organism there. He says that the state pollution control board
hardly does any survey of the area. “TNPCB should release data on
levels of pollution in Ennore Creek every fortnightly or even monthly
so that fishermen as well as people are aware of the pollution
levels,” he said.



The biggest issue is unchecked pollution of Ennore Creek. “While
industries claim of zero discharge in paper but in reality it is
totally different,” he said.



Jaikumar says that that there is a necessity now to biologically
monitor the creek water as well as fish meant for consumption. He says
that safe disposal of domestic sewage and industrial effluents should
be practiced and where possible, recycled to avoid metals and other
contaminants from going into the marine environment.



Factfile:

-- Moderate consumption of fish with low mercury levels is not likely
to result in worrying levels of exposure for humans.

-- People who consume higher amounts of contaminated fish  may be
highly exposed to mercury and are, therefore, at risk.

--- Pregnant women and young children should avoid consumption of
contaminated fish from polluted waters

--- Arsenic in seafood is carcinogenic. It can cause lung and skin
cancer nausea, diarrhea, vomiting peripheral nervous system problems

--- Cadmium consumed through fish affects calcium metabolism, and
therefore can cause bone mineral loss, with associated bone pain,
osteoporosis, and fracture

-- If one ingests high level of Zinc from seafood for several months,
it could cause anemia, damage to pancreas, decrease levels of high
density lipoprotien (HDL) Cholestrol.