Pesticides protect vegetables and other farm crops from pests and diseases, but undo this protection on humans causing them health problems. Those nice, fresh-looking, worm-free vegetables that you see in the markets are oftentimes coated inside and out with pesticide residues.
Many studies have shown evidence of pesticide residue contamination in vegetables. This was further confirmed by the research work led by Ms. Danila S. Paragas of the Central Luzon State University (CLSU).
According to the Philippine Council for Agriculture, Forestry and Natural Resources Research and Development of the Department of Science and Technology (PCARRD-DOST), which monitored the study, majority of vegetable farmers spray pesticides on their crops almost every two to seven days during the crops’ growing period. The study also revealed that farmers spray one or two days before harvesting to protect their produce from insect damage that could lessen its attractiveness and price. This explains why vegetables are laden with pesticide residues.
Samples of vegetables, namely ampalaya (bitter gourd), talong (eggplant), and sitao (string beans) collected from the public markets of three study sites in Central Luzon proved positive for residues of organophosphate pesticides, specifically Chlorpyrifos and Malathion, which ranged from 0.1-0.7 ppm; and carbamate pesticides, namely Carbaryl and 2-sec Butyphenylmethylcarbamate or BPMC, ranging from 0.2-3.73 ppm. The good news is that these pesticide levels were below the maximum residue limits (MRL) of 0.2-5 ppm set by the Codex Alimentarius Commission of the Food and Agriculture Organization (FAO) and World Health Organization (WHO).
Nevertheless, staying below the MRL is not an absolute assurance of safety for consumers. While some chemicals degrade or diminish quickly through the action of microorganisms or some substances, or by exposure to heat, other chemicals are not easy to degrade and they may stay in our bodies for a long time.
According to the Guelph Turfgrass Institute, most organophosphate pesticides have a half-life of less than 30 days, which means that after about 30 days, only half of the total amount of the compound is degraded, and the other half remains active. On the other hand, carbamates persist in the environment, or are not totally degraded within 30-100 days. The worst group of pesticides, the organochlorines, which are already banned in the market, have a half-life of several years. For example, DDT has a half-life of 15 years.
Thus, with daily intake of pesticide-contaminated vegetables, a person can accumulate pesticide residues in his/her body over a period of time, and may exceed the acceptable daily intake (ADI), which could pose health risks to the person. One can also take in pesticide residues beyond the ADI from a meal of different vegetables that have pesticide residues even below the MRL.
The repeated intake of pesticide residues can have different chronic or long-term effects on human health. For one, the toxic chemicals that go into our bodies can strain the kidney or liver, which detoxifies the chemicals, causing different kinds of diseases including cancer.
Taken in large quantities, pesticides affect the nervous system, which can result in acute or fatal effect. However, for babies and children, as well as developing fetuses, even small amounts of pesticide residues can result in abnormal development of the brain and nervous system, which might eventually affect their behavior or learning abilities.
Therefore, knowledge of health risks from chemical pesticide-contaminated vegetables should guide the general public, prompting the need for thorough washing of vegetables, especially those that are eaten raw.
Strict enforcement of policies and intensive information and education campaigns to correct farmers’ practices on pesticide usage, reduction in the use of chemical pesticides, and promotion of integrated pest management (IPM) and safe alternatives to chemical pesticides are required for the protection of the farmers themselves, the consumers, and the environment as well.