Pesticides may kill pests but it may also contaminate water, infect animals, and pose some health risks.

This was revealed by a professor from the University of the Philippines-Los Baños, on Thursday during the 10th Science Council of Asia Conference, conducted by the Department of Science and Technology-National Research Council of the Philippines (DoST-NRCP).

Dr. Leonila Varca of UP-Los Baños said that the use of pesticides causes ecological disruption, environmental contamination, and also affects non-target organisms.

“Application of pesticides to crops and soil can lead to diffuse source pollution which can reach the soil, surface water, ground water and air,” Varca said.

It was discovered that in past insecticides application in various areas, the water was contaminated with chemicals. In 2008, there was malathion concentration in the water at Lucban, Quezon. In the same year, profenofos was found in surface water of the Salasad Creek, Pagsanjan.

Malathion and profenofos are commonly used in agriculture and pest control programs such as mosquito extermination.

Prolonged exposure to insectides will affect the eye, skin, respiratory tract, heart, gastrointestinal tract and the nerves. A person may experience pterygium, in which a vascular membrane forms over the cornea, decreasing a person's visual acuity. Skin diseases like eczema and respiratory problems such bronchial asthma, characterized by cough, colds, and sputum formation, may occur.

Long term exposure may cause high blood pressure because of low tissue oxygenation. Pesticides also cause chronic gastritis. Signs of chronic gastritis are nausea, vomiting, and epigastric pain.

Farmers in Quezon, Laguna, and Nueva Ecija were diagnosed with such conditions due to pesticide exposure.

Majority of farmers from Quezon have cardiovascular problems, while most Laguna farmers have gastrointestinal tract problems. Meanwhile, the most prevalent health condition due to pesticide exposure recorded in Nueva Ecija was pterygium.