Pesticide: The effects on the environment

They are complex and vary depending on many factors, including in particular:
- Toxicity and ecotoxicity of the active ingredient, surfactants or adjuvants associates, their degradation products (sometimes more toxic than the parent molecule) and / or their metabolites;
- A possible synergistic action with other pollutants or compounds to the environment or the body affected;
- The length of half-life of active metabolites, or (if the active ingredient is biodegradable or degradable);
- Exposure time and dose (chronic exposure to low dose exposure to high doses during a short time);
- The relative sensitivity of the organs of the body, the ecosystem exposed at exposure and over time if the product or its effects are persistent;
- Age of the organ or body exposed (the embryo, fetus, cell under multiplication are generally more sensitive to toxic).

Pesticides may be responsible for diffuse pollution and chronic and / or acute and accident during their manufacture, transport, use, or for the disposal of products at the end of life, damaged, unused or banned.

Pesticides, their degradation products and their metabolites can contaminate all the compartments of the Environment;
- Air (outside, inside), as was shown some étude4 made over 3 years by the Institut Pasteur de Lille, in northern France from 586 samples taken on 3 different sites (3 gradiant population / urbanization and intensive agriculture).
- Water (salt, brackish, freshwater, groundwater, surface). Meteoritic water (rain, snow, hail, fog, dew are concerned),
- Soil. Some pesticides are highly degradable little adsorbed on the soil they can pollute lasting (chlordecone, eg paraquat)


... Some persistent pesticides can - long after their use, persist and move from one compartment to another, or passively (desorption, evaporation, erosion ...) or via active biological processes (metabolism, bioturbation, bio, etc.. ). An example of DDT found even decades after its ban in some areas, remote from any source of pollution.

They are found in the form of "residues" (parent, sub-products and degradation products or metabolites) in our food and drinks. Laws or directives impose limits not to exceed, including in drinking water.

Effects on quality

This is an issue.
The manufacturers suggest that pesticides improve product quality, including reducing the risk of growth of certain bacteria or fungi that produce toxins.
But critics of pesticides or their use argue that:
number of these pathogens gradually develops resistance to pesticides, such as the face microbes to antibiotics used too.
pesticide residues accumulated in and on plants or animal products could pose problems for health
pesticide residues could be problematic for animals that eat the waste from the food industry
soils that degrade under the action of pesticides eventually produce fruit and vegetables of poor quality.

According to a study by the University of California, published in the journal Chemistry & Industry (26 March 2007), researchers compared the kiwifruit orchard of the same products at the same time, some in farming, and others with pesticides. At harvest, kiwifruit bio contained significantly more vitamin C, plus minerals and polyphenols (organic compounds supposedly "healthy", because reducing the formation of free radicals). Researchers estimate that the untreated kiwifruit better develop their defense mechanisms, being more stressed, they produce more of such antioxidants.



Risks and hazards to human health

Various types of poisoning

Acute

The delay between the exposure and the onset of disorder is relatively short, a few hours to several days, allowing most of the effects linked to the cause.

Organochlorine derivatives induce first digestive disorders (vomiting, diarrhea), followed by neurological disorders (headache, vertigo) with great fatigue. In this succession of convulsions and sometimes loss of consciousness. If the subject is treated in time, the move towards a healing generally occurs without sequelae. Acute poisoning with this type of product is relatively rare, unless voluntary ingestion (suicide) or accidental (absorption by mistake, drifting cloud, jet sprayer ...).

Organophosphorus derivatives and carbamates, inhibit cholinesterase, induce an accumulation of acetylcholine in the body leading to hyperactivity of the nervous system and a cholinergic crisis. Clinical signs are digestive disorders with salivary hypersecretion, nausea, vomiting, abdominal cramps, profuse diarrhea. There are more trouble breathing with bronchial hypersecretion, cough and shortness of breath. The heart is tachycardia with hypertension and hypotension. Neuromuscular disorders result in frequent and rapid contractions of all muscles, involuntary movements, cramps and general muscular paralysis. Death occurs rapidly by asphyxiation or cardiac arrest. A specific antidote exists for this product category: atropine sulphate, which quickly neutralizes the toxic effects.

In adults, the products based rodenticides anticoagulants do not usually to less absorption but mass-suicide of bleeding disorders or bleeding. For against, in children, severe hemorrhage can occur. They work by lowering the rate of prothrombin in the blood necessary for the formation of blood clots, leading to internal bleeding. Symptoms appear after a few days to a high dose, after a few weeks for repeated blood in the urine, nosebleeds, gingival bleeding, blood in the stool, anemia, weakness. Death can occur within 5 to 7 days.

According to the Mutualité Sociale Agricole (MSA) and the laboratory GRECAN, first MSA studies in France have concluded that about 100 to 200 acute poisoning (skin irritation, digestive disorders, headaches) per year are attributed to pesticides.

Chronic poisoning

Atteintes skin reddening, itching with the possibility of cracking or ulceration, urticaria are frequently observed, affecting rather the parts of the body (arms, face). Number of products cause skin problems, including rotenone responsible for severe damage to the genital regions.

Neurological: organochlorines show a muscular fatigability, decreased tactile sensitivity. Organophosphates cause long-term headache, anxiety, irritability, depression and insomnia, combined sometimes hallucinatory disorders. Some cause paralysis, such as arsenic or mercury derivatives.

Disorders of the hematopoietic system: organochlorines may cause a decrease in the rate of red blood cells and white blood cells, with risk of leukemia.

Violations of the cardiovascular system: the development of organic phenomena and palpitation of the heart rhythm disturbance.

Violations of the respiratory system: such attacks are often related to the phenomena of irritation caused by a number of pesticides, thus encouraging superinfections and cause bronchitis, rhinitis and pharyngitis.

Atteintes sexual function: a nematicide (DBCP) has caused the employees of the factory where it is synthesized a large number of cases of infertility. Other substances appear involved in the deletion of increasing spermatogenesis, either directly as reproductive or at low doses or via coktails products like endocrine disruptor. In this case, the embryo can be affected even by exposure to low doses (genital anomalies, and possibly increased risk of certain cancers and deletion of spermatogenesis in the future adult).

Fetal risk: pesticides crosses the placental barrier and have a teratogen on the embryo. This is the case of DDT, malathion and phthalimide (fungicide near thalidomide). There may be premature deliveries or abortions, and malformations of the genitals of the boy. It is advisable for pregnant women to avoid contact with pesticides between the 23rd and 40th days of pregnancy, but some products have a long half-life in organisms (lindane, DDT, for example).

Neurodegenerative diseases: A study published in 2006 concluded that an increased risk of Parkinson's disease following exposure to certain pesticides, such as ... see the summary.

Cancers: The GRECAN revealed a lower incidence of cancer among farmers than in the general population, but with a higher occurrence of certain cancers (prostate, testis, brain (glioma )...). Worldwide, there are some thirty studies which all show a higher risk of brain tumors. According to the INSERM there appears to be a relationship between testicular cancer and exposure to pesticides 5.

The study by Isabelle Baldi: A study concluded in mid-2007 that the risk of brain tumor is more than doubled among farmers very vulnerable to pesticides (all tumor types combined, the risk of glioma is tripled). The people using pesticides on their indoor plants are also more than doubled risk of developing a tumor cérébrale6 The study does not say whether a product or family of pesticides would be more responsible than others, but the author notes that the fungicides are 80% of pesticides used by the tenants.

Prevention and Control

Since 2006, the Agence française de sécurité sanitaire des aliments (AFSSA) is responsible for testing pesticides on the market before their approval. Thus, Afssa banned in 2001 the treatment of vines with arsenic after the discovery of suspicious diseases.

Children are particularly vulnerable. According to a study published in 2008 by the EPA, many babies do not develop the capacity to metabolize (degrade) the pesticides they have absorbed during the first 2 years of their lives, which exposes particular. The EPA has banned two pesticides to domestic UDA (Diazinon and Chlorpyrifos), which led to a rapid decrease of these products and exposure of these products in New York, where children were in better health since prohibition of these produits7. Moreover, per kilogram of body weight, as with most toxic, children breathe in and absorb more (on average) than adults.

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