Developement news | 25 Apr 2012
Harmful effects of pesticides, fertilizers due to poor usage
Both chemical fertilizers and pesticides are associated to water pollution when erosion carries the chemicals from farms along with eroded soils after rainfall.
These useful pesticides are dangerous when application norms are not respected
The use of chemical fertilizers in place of animal or “green” manure has been linked to the depletion of soils of organic matter, making them lose their ability to hold exposing them to erosion.
Nitrogen fertilizers have reportedly found their way into rivers, lakes and the ocean, killing aquatic life. For example, roundup, an extremely common herbicide used in agriculture, is highly toxic to fish and amphibians.
There are also concerns that pesticides pose a risk, not only to non-target animal and plant species, but to humans. Chemical pesticides are believed to be the main causes of health problems in rural areas where mostly ignorant users apply them extensively in order to have good yields.
In fact, most of the health problems are because of wrong usage or complete lack of knowledge on the health hazards of chemical fertilizers and pesticides. Prolonged exposure to pesticides in humans can lead to severe disorders in our reproductive, nervous and immune system.
Pesticides have been linked to cancer. Pregnant women exposed to pesticides sometimes suffer increased child mortality and the pesticides sometimes lead to disorders in children including the loss of limbs in severe cases. Farmers who experience routine exposure to pesticides have exhibited neurological symptoms such as headache and hand tremors.
The following health hazards have been linked to pesticides by researchers
Researchers found an association between asthma and use of pesticides by male farmers. Although this study involved adults, it raises concerns about children’s exposures to pesticides used in the home or residues brought home on parents’ clothes or equipment. The research was done in the USA.
Commonly used pesticide like Chlorpyrifos (Dursban) caused severe birth defects when pregnant women or children are exposed. Chlorpyrifos is used widely as an agricultural chemical, but is also the most common pesticide used indoors to kill termites, fleas, roaches and in pest control in the USA. A study in Minnesota (USA) found significantly higher rates of birth defects in children born to pesticide applicators and in regions of the state where chlorophenoxy herbicides and fungicides are widely used.
Neurological (nerve) Effects
Pesticides are potent neurotoxins. When people are exposed to neurotoxins they may feel dizzy, light head ache, confused and may have reduced coordination and ability to think. These are the short-term effects, while long term exposure can result in reduced IQ and learning disability, associated with permanent brain damage. Until recently, few studies could link permanent brain damage to such exposures. There is new evidence that prolonged exposure to pesticides in areas where they are used routinely may cause permanent brain damage to children who live in these areas.
It is difficult to get statistics about infections in Cameroon but researchers have showed a link between cancer and use of pesticides in the USA. Researchers in the US proved that the risk of brain cancer increases with pesticide exposure.
While some substances cause physical birth defects, others can cause subtle hormonal effects on the developing fetus or affect a child’s functional capacities. Hormone disruptors have been linked to many health problems including reproductive cancers. Apart from risks of reproductive cancers, animal studies in the US link many poor health conditions to prenatal exposure to hormone disrupting substances.
Alternatives available for chemical pesticides
Microbial pesticides, insect breeding and genetic engineering could be good alternatives. Researchers say these methods have proven to be safer than traditional chemical pesticides. The problem here is that they are sometimes not as cheap and available as chemical pesticides.
This is true of a country like Cameroon where close to 90% of the farmers practice subsistent farming. A classical example of using insect breeding to eliminate pests was introduced in PAMOL, in the 1980s during Late Dr Timti era as chief researcher. A certain species of black ants were introduced to palms so that they can feed on the larva of pests that were damaging palm fronts thus inhibiting production.
Compiled by Bangsi Daniel Song with information from http:www.kidsforsavingearth.org
“I don’t use pesticides when the crops are ready for harvesting”,
Mepong Soffack, Vegetable farmer, Buea
Which crops do you cultivate?
I work tomato, cabbage, lettuce, green beans and other leafy vegetables.
What quantities do you produce?
I work tomato twice every year. The others are done when it is their season in large quantities.
Which kind of fertilizers do you use?
I use ‘20 10 10’ for all the vegetables.
When do you apply the fertilizer?
I apply fertilizers 30 days before harvesting the crops to avoid residues.
Which pesticides do you use?
I use insecticides and pesticides to treat the plants from pests.
Do you have any period of harvesting after treating your farm?
In the raining season I give 8 days since I don’t use systemic chemicals on the vegetables. I don’t use pesticides when the crops are ready for harvesting.
Do you know that pesticides are very poisonous if wrongly used?
I know that they kill. Farmers should avoid applying much of them, that’s why I mix it with local treatment and also use droppings sometimes instead of fertilizers. I mostly use droppings on vegetables. In this way now I try to calculate my expenditure in advance. In case I am planting 200 plants, I know how much of the fertilizer I have to use.