Clam fishermen, diving down the pretty lakes of the south Indian State of Kerala armed with nothing but a scoop net to collect clams, apparently seem to be unaffected by any serious occupational hazard. Appearances are deceptive, for the National Institute of Speech and Hearing (NISH) here, has found that backwater professionals such as clam and shell collectors stand a high risk of hearing impairment.
Unlike the Scuba divers, who dive for professional or recreational purpose, the clam fishermen have no protective gear while diving.
A majority of them have an underwater exposure of 4 hours a day while in around 40 percent of the clam fishermen the duration can go up to 6 hours a day.
In the lake and also along the coast, pressure increases with depth. Since these clam fishermen are continuously exposed to backwater during diving, it was found that they are prone to middle ear problems, especially those caused by changes in pressure, said NISH senior audiologist Praveena Davis, who had done the study along with Vipinkumar K P and Sreebha Sreedhar.
The NISH study is highly significant to communities living near the backwaters and estuaries in the state, for whom clam fisheries is an important means of livelihood.
While clam meat is nutritious and tasty, the clam shell with as much as 35 percent of calcium content, is used as raw material by a number of industries such as cement, lime and washing soda.
The NISH team, along with the Black Lime Shell Society, Alappuzha, conducted two camps and examined 61 persons in the age group 25-60. As the clam fishery sector has the active participation of women as well, the selected group had 45 men and 15 women.
The hearing threshold level of the participants was determined and obtained data were statistically analysed.
Not only was there hearing loss but there were a lot of abnormalities in the tympanic membrane (TM) of the ear such as perforated tympanic membrane, retracted TM, sclerosis of TM, thin TM, thick TM and dull TM. In the study, 30 participants had less than 10 years of experience in underwater fisheries, 16 had 11-20 years of experience and 15 had 21-30 years of experience. The researchers found that the more the experience, the more was the hearing loss as well.
None of the fishermen was aware about ear protecting devices as a protective measure. It is high time that we thought of distributing ear plugs or some such protective device for our backwater professionals, especially when they spent so much time under water, said Praveena Davis.
Decades earlier, the wax in the ears of the divers was thought to be adequate protection. But with the increased microbial load and industrial effluents being flushed into our waters, ear protection devices seem to be the only answer.
2012 The New Indian Express