Irrational use of pesticides harming ecology, public health: study
KARACHI, Aug 30: Irrational use of pesticides in lower Punjab and upper Sindh areas is found to be damaging environment as it has contaminated underground water, soil and even fruits and vegetables being grown there, said a study.
According to the study published by a German publishing house last year, a large number of people were also found to be suffering from different diseases.
The research book titled Pesticide Residues in Agriculture Commodities is authored by Dr Tahir Anwar Khan, an environmental toxicologist and in-charge of the Pesticide Research Institute of Southern zone, Agricultural Research Centre (SARC), at Karachi University.
The study, posted on the Higher Education Commission’s website, was conducted in the cotton growing villages of Shaheed Benazirabad (Nawabshah), Bhawalpur and Lodhran districts in 2008.
Under the study, 46 water, 43 soil, 24 fruit and 27 vegetable samples were monitored with two multi residue methods (MRM) employed for analysis of three classes of pesticides; organophosphate, pyrethroid and organochlorine.
The research’s findings showed that all water samples analysed were contaminated with pesticides (dichlorvos, mevinphos, dimethoate, methyl parathion, fenitrothion, chlorpyriphos, endosulfan and profenofos). Among these 70 per cent samples exceeded the maximum acceptable concentrate (MAC) for single pesticide and 30 per cent above the MAC for multiple pesticides set by the European Economic Commission (EEC).
Similarly, all the soil samples found contaminated with tested pesticide residues with varying degrees of concentration. The samples of fruit analysed were found 87.5 per cent contaminated and among these 28.5 per cent exceeded the maximum residues limits (MRL) of Codex Alimentarius Commission.
“The pesticides exceeded their MRLs were dimethoate, fenitrothion, cypermethrin and chlorpyriphos. All the samples of vegetable analysed were found contaminated and among these 37 per cent exceeded the MRL. The pesticides exceeded their MRLs were fenvalerate, dimethoate, fenitrothion, cypermethrin, deltamethrin and chlorpyriphos,” said the study.
One of the most alarming finding of the study was the observation that farmers were increasingly using cotton-specific pesticides on fruit and vegetable crops (cotton-specific pesticides are generally organophosphates and have long-term effects).
“The study confirms the gravity of the problem and reveals that pesticide residue have reached to even deeper aquifer. This could lead to a disastrous situation, if not checked on an emergency basis through a rational strategy to ensure both agricultural growth and environmental quality. The pesticides contaminate water, soil and food and accumulate in the soil for relatively longer period of time and then passed into various parts of the plant grown on the contaminated soil. It is concluded that to prevent adverse effects on public it is a must to carry out regular monitoring system and to establish control measures in order to ensure adherence to the standards on pesticide residues,” it said.A survey about farmers’ socio-economic background, health status of family, perceptions of use of pesticides and signs and symptoms related to pesticide use and exposure was also part of the research and was carried out in cotton growing areas of Sakrand, Daulatpur and Nawabshah tehsils of Shaheed Benazirabad district.
According to the survey, though the major land area was for cotton production, wheat, vegetables and fruits and other crops were also being grown in those areas. The most commonly growing crops were chillies, tomatoes, brinjal, bitter gourd, maize and sugarcane. Seventy-one per cent respondents had received primary education whereas 93 per cent farmers often applied pesticides in recommended (often by pesticide seller) dosages. However, they couldn’t understand the instruction labels which were either in English or Urdu.
It was also found that safe storage of pesticides, disposal of empty bottles and residue liquid properly was not observed. Most pesticides were stored in houses and often empty bottles were left in the field (59 per cent) after use. Sixty-four per cent farmers adopted no precautionary measures while others used a piece of cloth to cover their face during spraying, which itself was a risk factor as pesticide residues tend to accumulate in that piece of cloth.
The information collected during the survey also showed that although many farmers (85 per cent) believed that pesticides were hazardous and were experiencing their adverse effects on their health, this awareness didn’t necessarily influence their behaviour. Most farmers (85 per cent), according to the study, reported the symptoms when they experienced exposure to pesticides. The symptoms they usually suffered following a round of spraying in the field or later included dizziness, headache, tiredness, excessive sweating, salivation, nervousness, short breath, cold legs and hands at night, stomach cramps, vomiting, red eyes, coughing and unconsciousness.
Some long-time users of pesticides complained of shivering and numbness. Almost half of the respondent believed that pesticides made them ill as spray entered their body through the skin and also by inhalation.
“We found a significant number of childless farmer families who had received no treatment for infertility. The scale of stillbirths was high and respiratory problems were common,” said Dr Khan.
Further elaborating upon the ill effects of the pesticide residues on human health, Dr Khan said that though it was difficult to establish a direct link between the two in the absence of an epidemiological study, the occurrence of specific diseases, including cancer, as a result of exposure to certain pesticides had already been established in the developed world.
“And, the fact that majority of farmers working in the same environmental conditions were found to be suffering from those health problems suggest that there is an immediate need for measures to save environment and public health. The case of women cotton-pickers especially those who are pregnant also requires urgent attention,” he observed.
Giving some statistics on the use of pesticides especially in Pakistan, he said that the use of pesticides had increased rapidly in the developing world and it was believed that one fifth of all pesticides were consumed here.
In Pakistan, he added, pesticides were introduced in 1954 with 254 metric tons of formulation but the Agricultural Pesticide Ordinance and Rules were adopted almost 17 years later in 1971 and 1973, respectively. By mid-1960s pesticide consumption has reached over 7,000 tonnes per annum, increasing to the level of 45,680 metric tons in 1999.
At present, more than 108 types of insecticides, 30 types of fungicides, 39 types of weedicides, five types of acaricides and six different types of rodenticides were being used in Pakistan.
“The situation in villages hasn’t changed, though imports of pesticides has dropped over the past few years, but the question remains over their rampant irrational use among farmers, lack of training on how to use pesticides, their unsafe disposal and availability of fake pesticides in the market,” he said while regretting the lack of implementation of food and agricultural regulation which called for pesticide residue examination of products seeking registration in the country.
Regarding the use of pesticides on cotton, he said that the crop was an important cash crop of Pakistan with 60 per cent export earnings. The crop suffered about 20 to 40 per cent losses from many insect pests, which were tackled by majority of farmers solely through pesticides.More than 76 per cent of the total consumption of pesticides in the country found its way into the cotton crop eco-system because the plants were repeatedly sprayed with pesticides, although the area under this crop occupied merely 8 per cent of the total cultivable land.
“Resistance in pests and adulterated products are two major reasons that force farmers to the frequent use of pesticides,” he explained.
Recalling how people responded when he told them about pesticides’ health hazards, Dr Khan said: “A man laughed off and argued that how could they harm their bodies when they couldn’t even kill the germs they are being applied for. But, the reality is that a single molecule of a pesticide can disturb the hormonal system of both humans and animals”.