Pesticide residue

Pesticide residue refers to the pesticides that may remain on or in food after they are applied to food crops. The levels of these residues in foods are often stipulated by regulatory bodies in many countries. Exposure of the general population to these residues most commonly occurs through consumption of treated food sources, or being in close contact to areas treated with pesticides such as farms or lawns around houses.

Many of these chemical residues, especially derivatives of chlorinated pesticides, exhibit bioaccumulation which could build up to harmful levels in the body as well as in the environment. Persistent chemicals can be magnified through the food chain and have been detected in products ranging from meat, poultry, and fish, to vegetable oils, nuts, and various fruits and vegetables.

Definition

See also: Pesticides

A pesticide is a substance or a mixture of substances used for killing pests: organisms dangerous to cultivated plants or to animals. The term applies to various pesticides such as insecticide, fungicide, herbicide and nematocide. Applications of pesticides to crops and animals may leave residues in or on food when it is sold, and those specified derivatives are considered to be of toxicological significance.

Background

From post-World War II era, chemical pesticides have become the most important form of pest control. There are two categories of pesticides, first-generation pesticides and second-generation pesticide. The first-generation pesticides, which were used prior to 1940, consisted of compounds such as arsenic, mercury, and lead. These were soon abandoned because they were highly toxic and ineffective. The second-generation pesticides were composed of synthetic organic compounds. The growth in these pesticides accelerated in late 1940s after Paul Müller discovered DDT in 1939. The effects of pesticides such as aldrin,dieldrin, endrin, chlordane, parathion, captan and 2,4-D were also found at this time. Those pesticides were widely used due to its effective pest control. However, in 1946, people started to resist to the widespread use of pesticides, especially DDT since it harms non-target plants and animals. People became aware of problems with residues and its potential health risks.

Regulations

Each country adopts their own agricultural policies and Maximum Residue Limits (MRL) and Acceptable Daily Intake (ADI). The level of food additive usage varies by country because forms of agriculture are different in regions according to their geographical or climatical factors.

International

Some countries use the International Maximum Residue Limits -Codex Alimentarius to define the residue limits; this was established by Food and Agriculture Organization of the United Nations (FAO) and World Health Organization (WHO) in 1963 to develop international food standards, guidelines codes of practices, and recommendation for food safety. Currently the CODEX has 185 Member Countries and 1 member organization (EU).

The following is the list of maximum residue limits (MRLs) for spices adopted by the commission.

Pesticide	Group or Sub-Group of Spices	MRL (mg/kg)
Acephate	Entire Group 028	0.2
Azinphos-methyl	Entire Group 028	0.5
Chlorpyrifos	Seeds Fruits or berries Roots or rhizomes	5 1 1
Chlorpyrifos-methyl	Seeds Fruits or berries Roots or rhizomes	1 0.3 5
Cypermethrin	Fruits or berries Roots or rhizomes	0.1 0.2
Diazinon	Seeds Fruits Roots or rhizomes	5 0.1 0.5
Dichlorvos	Entire Group 028	0.1
Dicofol	Seeds Fruits or berries Roots or rhizomes	0.05 0.1 0.1
Dimethoate	Seeds Fruits or berries Roots or rhizomes	5 0.5 0.1
Disulfoton	Entire Group 028	0.05
Endosulfan	Seeds Fruits or berries Roots or rhizomes	1 5 0.5
Ethion	Seeds Fruits or berries Roots or rhizomes	3 5 0.3
Fenitrothion	Seeds Fruits or berries Roots or rhizomes	7 1 0.1
Iprodione	Seeds Fruits or berries Roots or rhizomes	7 1 0.1
Malathion	Seeds Fruits or berries Roots or rhizomes	2 1 0.5
Metalaxyl	Seeds	5
Methamidophos	Entire Group 028	0.1
Parathion	Seeds Fruits or berries Roots or rhizomes	0.1 0.2 0.2
Parathion-methyl	Seeds Fruits or berries Roots or rhizomes	5 5 0.3
Permethrin	Entire Group 028	0.05
Phenthoate	Seeds	7
Phorate	Seeds Fruits or berries Roots or rhizomes	0.5 0.1 0.1
Phosalone	Seeds Fruits or berries Roots or rhizomes	2 2 3
Pirimicarb	Seeds	5
Pirimiphos-methyl	Seeds sub group Fruits sub group	3 0.5
Quintozene	Seeds sub group Fruits or berries Roots or rhizomes	0.1 0.02 2
Vinclozolin	Entire spice group	0.05

European Union

See also: Pesticides in the European Union

In September 2008, the European Union issued new and revised Maximum Residue Limits (MRLs) for the roughly 1,100 pesticides ever used in the world. The revision was intended to simplify the previous system, under which certain pesticide residues were regulated by the Commission; others were regulated by Member States, and others were not regulated at all.

New Zealand

Main article: Pesticide residues in New Zealand

Food Standards Australia New Zealand develops the standards for levels of pesticide residues in foods through a consultation process. The New Zealand Food Safety Authority publishes the maximum limits of pesticide residues for foods produced in New Zealand.

United Kingdom

Monitoring of pesticide residues in the UK began in the 1950s. From 1977 to 2000 the work was carried out by the Working Party on Pesticide Residues (WPPR), until in 2000 the work was taken over by the Pesticide Residue Committee (PRC). The PRC advise the government through the Pesticides Safety Directorate and the Food Standards Agency (FSA).

United States

In the US, tolerances for the amount of pesticide residue that may remain on food are set by the EPA, and measures are taken to keep pesticide residues below the tolerances. The US EPA has a web page for the allowable tolerances. In the US, the Food and Drug Administration (FDA) and USDA also routinely check food for the actual levels of pesticide residues.

Japan

In Japan, pesticide residues are regulated by the Food Safety Act.

Pesticide tolerances are set by the Ministry of Health, Labour and Welfare through the Drug and Food Safety Committee. Unlisted residue amounts are restricted to 0.01ppm.

China

In China, the Ministry of Health (China) and the Ministry of Agriculture (China) have jointly established mechanisms and working procedures relating to maximum residue limit standards, while updating them continuously, according to the Food safety Law and regulations issued by the State Council. From GB25193-2010 to GB28260-2011 , from Maximum Residue Limits for 12 Pesticides to 85 pesticides, they have improved the standards in response to Chinese national needs.

Health Impacts

Pesticide exposures can produce two distinct types of adverse health effects – acute (short-term) effects and chronic (long-term) effects. The severity of adverse health effects are determined by following factors: the dose, the route of exposure, an individual’s genetic vulnerability, age at the time of exposure and general health condition; the length of exposure, environmental factors and intakes with other chemicals through other factors.

Chronic Impacts

Possible symptoms of Long term pesticide exposure are listed as follows.

• Increased risk of cancer
• Neurological impairment (e.g Parkinson’s disease)
• Developmental effects
• Reproductive effects
• Organ damage
• Intrusion with the human hormone system

Many pesticides achieve their intended use of killing pests by disrupting the nervous system. Due to similarities in brain biochemistry among many different organisms, there is much speculation that these chemicals can have a negative impact on humans as well. There are also studies that show positive correlations between exposure to pesticides through occupational hazard, which tends to be significantly higher than that ingested by the general population through food, and the occurrence of certain cancers. Although the most of the general population may not exposed to large portion of pesticides, many of the pesticide residues that are attached tend to be lipophilic and can bioaccumulate in the body. Concerns have been raised about the possible role of continuous low-dosage exposure in causing certain cancers.

On the other hand, pesticide use has proven to be a valuable tool in combatting disease vectors that spread illness to millions of children and adults each year. They are used in many developing countries to prevent the spread of malaria, leishmaniasis, dengue, and Japanese encephalitis which are diseases that have an enormous economical burden on society.

Acute Impacts

Some health effects from pesticide exposure may occur immiediately following exposure. Symptoms of immediate body reaction against pesticide are as follows:

• Eyes: tearing, irritation, conjunctivitis
• Skin: rash, blistering, burns, sweating, contact dermatitis, jaundice
• Nervous system: headache, dizziness, mood disturbances, depression, stupor, muscle twitching, lack of coordination, seizures, paralysis, loss of consciousness, coma
• Respiratory system: throat pain, rhinorrhea, cough, pulmonary edema, difficulty in breathing, respiratory failure
• Cardiovascular system: cardiac arrhythmias
• Gastrointestinal tract: nausea, vomiting, diarrhea, abdominal pain

Acute poisoning can happen in various situations; by consuming food containing pesticide residue, including the accidental ingestion in the home, garden, farm or forest. Children are the most vulnerable to poisoning as they have not yet built up antibodies to certain toxicities.

Pesticide poisoning

In August 1994, a serious incident of pesticide poisoning of sweet potato crops occured in Shandong province, China. Because local farmers were not fully educated in the use of insecticides, they used the highly-toxic pesticide named parathion instead of trichlorphon. It resulted in over 300 cases of poisoning and 3 deaths. Also, there was a case where a large number of students were poisoned and 23 of them were hospitalized because the vegetables they cosumed contained pesticide residues.

Child neurodevelopment

See also: Child development

Children are thought to be especially vulnerable to exposure to pesticide residues, especially if exposure occurs at critical windows of development. Due to the greater intake of food relative to bodyweight in children, bioaccumulation effects can prove to be especially harmful. Neurotoxins and other chemicals that originate from pesticides pose the biggest threat to the developing human brain and nervous system. Since precise spacial and temporal information must be communicated between cells for the proper development of the human CNS, disruptions in the form of miscommunication or damage to neurons can result in permanent and irreversible damages. Presence of pesticide metabolites in urine samples have been implicated in disorders such as attention deficit hyperactivity disorder (ADHD), autism, behavioral and emotional problems, and delays in development. There is a lack of evidence of a direct cause-and-effect relationship between long-term, low-dose exposure to pesticide residues and neurological disease, partly because manufacturers are not always legally required to examine potential long-term threats.

Dirty Dozen

• celery
• peaches
• strawberries
• apples
• domestic blueberries
• nectarines
• sweet bell peppers
• spinach, kale and collard greens
• cherries
• potatoes
• imported grapes
• lettuce

Clean Fifteen

• onions
• avocados
• sweet corn
• pineapples
• mango
• sweet peas
• asparagus
• kiwi fruit
• cabbage
• eggplant
• cantaloupe
• watermelon
• grapefruit
• sweet potatoes
• sweet onions

Organic vs Non-organic

Even though some organic foods contain significantly less amounts of pesticides than non-organically produced products, they still contain certain amounts of residue levels that are persistent in the environment. The methods of organic farming prohibit the use of many pesticides, however certain chemicals could be persistent in the soil, reach the organic produce via pesticide drift from nearby farms, or contaminate produce during transportation to the consumer. It was found that produce grown using organic methods had one-third the amount of pesticide residue compared to non-organically produced food. Also, in comparison to food that was grown using Integrated pest management techniques, organic produce showed about 50% less residue. Organic produce has also been shown to generally have a greater level of iron, magnesium, vitamin C, phosphorus, and antioxidant phytochemicals.

Minimizing exposure to pesticide residues

In addition to choosing to buy organic produce, there are certain measures that can be taken to minimize exposure to harmful residues: vegetables washes may help remove chemical residues, peeling fruits and vegetables that have known high levels of pesticide residues, and growing your own essential produce.

See also

• Pesticide poisoning
• Food safety
• Environmental effects of pesticides
• Environmental issues with agriculture
• List of environmental issues

External links

• The European Pesticide Residue Workshop
• Pesticide residue in Europe
• International Maximum Residue Level Database
• UK Pesticides Safety Directorate
• List of websites that specify pesticide residue limits
• US EPA Pesticide Chemical Search
• CODEX Alimentarius International Food Standards

• Pesticides and Food:What the Pesticide Residue Limits are on Food