Food contamination from pesticides
Ingestion of pesticides through contaminated food supplies is a cause of concern for almost every one.This was most serious at the time when persistent insecticides, (organ chlorines) were commonly used
on crops. There are many examples of pesticide poisoning through food (Hayes 1982). In Pakistan, very little information is available on the subject.Between 1978-85 the federal pesticide research laboratory at Karachi conducted studies on food contamination. In all these findings DDT was the only pesticide monitored. In the first instance, the ‘DDT under semi-field conditions of 5-7 sprays was found to be 0.8-1.3 ppm in cotton seed oil.
Moreover, the cotton seed oil from aerial sprayed cotton contained 0.18-0.92 ppm of DDE an isomer of DDT. These values were below the FAO/WHO limits of 0.5-5.00 ppm for DDT and isomers, like DDE.
These experiments were carried out about 15 years ago when DDT was used abundantly.Processing of cotton seed oil a further decline in DDT is expected. The study was inconclusive as it did
not investigated market products i.e., vegetable oil and `ghee’ manufactured from cotton seed oil (Baig 1985).The federal pesticide laboratory has a continuous programing of assessing market food produces for
Contamination by pesticides and the results are periodically published in various journals. Such Dissemination of the findings means that hardly any notice is taken and the decision whether to continue
or discontinue the use of a particular pesticide rests with either voluntary withdrawal on the part of the company or through a government directive but not public reaction. These actions are based on the
in formation generated in the other countries. If the laboratory is linked (through a working relationship)with the Environmental Protection Agencies then it might perform a more useful function. A survey by
Masud and Hasan (1992) on 59 different fruit and vegetables procured from wholesale market of Karachi during July 1988 to June 1990 revealed that out a 250 samples screened, 93 samples were contaminated
with a variety of pesticides. Forty five samples were found to contain residues above the maximum residue limit (MRL’s) proposed by FAO/WHO. This kind of study is most useful to draw our attention
towards the dangerous state of our food. However the way it was conducted it falls short in isolating the source of contamination whereby some legal or other remedial actions could be taken. This is true for the
other survey conducted by NIH (1984) as well, since the market sample is a composite sample and the origin is unknown so the source of pollution cannot be located. For that matter, a detailed and continuous
monitoring programe is required. With stringent international legislation prohibiting import of contaminated food and fiber items monitoring and reduction in the use of pesticides becomes even more
essential. Under the auspices of FAO a comprehensive study on food contamination and control was carried out during 1981-84 at the National Institute of Health, Islamabad. Four major areas studied were pesticide
residues, metal contaminants, aflatoxins, and microbial contaminants. The reported results (NIH 1984) on pesticide residues revealed the presence of 23 out of 25 pesticides tested but to a varying degree. The
food samples were collected from local markets and grouped in 6 different categories: (1) dairy products, (2) meat, fish and poultry, (3) grain and cereal products, (4) vegetables, (5) fruits, and (6) oil, fats and
shortenings. To overcome some practical problems, particularly for reducing the number of samples to manageable limits, samples of produce collected from various localities were pooled. This had two
implications; firstly there was a dilution of the pesticide residues by combining contaminated and pesticide free samples ; secondly it was difficult to ascertain whether the contaminant originated from a
particular locality or was present in all the samples.
WRITTEN BY
Rao Adeel ur Rehman
Department of soil and environmental sciences UCA, University of Sargodha
Hamza bin Riaz
Department of soil and environmental sciences UCA, University of Sargodha
Muhammad wasim akram
Department of Entomology ,UCA, University of Sargodha
Email id;[email protected]
