‘Rice bowl’ turning into ‘poison bowl’

ALAPPUZHA: Fertilizer and pesticide pollution affect the fishery resource of Kuttanad, according to a study conducted in 2014.
The study titled ‘Effect of artificial fertilizers on Kuttanad wetland ecosystem, the rice bowl of Kerala’ was conducted by Dr K Shiny Sreedhar of SN College, Cherthala.
As per the study, the indiscriminate use of fertilizers and pesticides cause severe pollution and insecticides and fungicides contribute a major bulk of pollution in Kuttanad.
The so-called less toxic fertilizers also proved to be harmful to the ecosystem.
The study says the low lying nature of Kuttanad and the lack of proper drainage facilities cause these chemicals to accumulate in Kuttanad’s wetland ecosystem. Thus these pollutants emptied into the Kuttanad water convert it from a ‘rice bowl’ into a ‘poison bowl’.
Shiny said continuous use of these fertilizers result in the depletion of naturally occurring soil nutrients and minerals, which makes the soil infertile. Chemical fertilizers have high salt content that are harmful to soil and plants. Thus they are expected to be harmful to agriculture in the long run.
“In the ecosystem continuous application of these chemicals cause nutrients enrichment, which results in high biological oxygen demand, depletion of oxygen, thereby creating an imbalance between organisms and the environment which also causes the reduction and destruction of some organisms like fish, frogs, snakes, and some useful pests and insects,’’ she said.
The study recommends that these fertilizers should be substituted by organic manure, biofertilizers or integrated farming system should be practiced or the overuse of agrochemicals should be regulated .
“Awareness should be given to the farmers and people residing in Kuttanad about the harmful effects of the overuse of fertilizers and pesticides to the ecosystem and humans. Faecal pollution revealed from the study in the area cause cholera, typhoid fever, which is to be controlled by proper treatment of wastewater, treatment of drinking water and immunizations to eliminate these diseases,’’ she said.
The biological response induced by an exogenous substance in different test organisms is diverse. The test organisms selected for the present investigation were the black clam and two Cichlidae fish species predominant in Kuttanad area.
Black clam is a major clam resource found in the backwaters of Kerala, mainly in the southern low saline areas of Vembanad Lake and contributes to over 70% of the total fish production from the lake. It is harvested extensively from the backwater in tons and thousands of people in Kerala depend on this species for their livelihood. It is very sensitive to changes in water quality.