The impact of pesticide residues on human health is a worldwide problem, as human exposure to pesticides can occur through ingestion, inhalation, and dermal contact. Regulatory jurisdictions have promulgated the standard values for pesticides in residential soil, air, drinking water, and agricultural commodity for years.
Until now, more than 19,400 pesticide soil regulatory guidance values (RGVs) and 5400 pesticide drinking water maximum concentration levels (MCLs) have been regulated by 54 and 102 nations, respectively.
Over 90 nations have provided pesticide agricultural commodity maximum residue limits (MRLs) for at least one of the 12 most commonly consumed agricultural foods. A total of 22 pesticides have been regulated with more than 100 soil RGVs, and 25 pesticides have more than 100 drinking water MCLs.
All of these were with the aim of making food production with pesticide sustainable as well as protecting human health and the environment. International and national legal frameworks governing pesticide management have however undergone significant changes over the past 25 years.
The International Code of Conduct on the Distribution and Use of Pesticides was adopted by FAO in 1985.
It was subsequently amended in 1989 to include the prior informed consent (PIC) procedure and revised in 2002. In 2013, it was updated to include public health pesticides and its title was changed to The International Code of Conduct on Pesticide Management (Code of Conduct). In 2014, the WHO also adopted the Code of Conduct as its reference framework for international guidance on pesticide management.
Legislative Basis for Pesticide Regulation
In the United States, the EPA regulates pesticide registration, manufacture and distribution under the authority of the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA).
In addition, the Federal Food, Drug and Cosmetic Act has authorized the EPA to establish tolerable levels for pesticide residues in foods.
The FIFRA requires that all pesticides distributed and sold in the United States be registered by the EPA after pesticide approval, which is granted upon determination that the substance “will not generally cause unreasonable adverse effects on the environment”.
The FIFRA defines “unreasonable adverse effects on the environment” as “(i) any unreasonable risk to man or the environment, taking into account the economic, social, and environmental costs and benefits of the use of any pesticide, or (ii) a human dietary risk from residues that result from a use of a pesticide in or on any food inconsistent with the standard under section 408 of the Federal Food, Drug, and Cosmetic Act” (WHO, 2017)
Regulation of pesticides is not backed by any law in many developing country, and where there are legislations, such laws are weakly enforced.
In the United States, a registrant must submit data on a given pesticide to the EPA for registration, as required by the FIFRA.
The EPA decides whether to register the pesticide based on the results of a risk–benefit evaluation, which weighs the pesticide’s potential adverse effects against the benefits of its use (NIST, 2014) Registration of the pesticide is not approved unless the pesticide meets:
(i) The efficiency and labelling requirements of the FIFRA; and
(ii) Has been shown to not generally cause “unreasonable adverse effects on the environment” (Global MRL, 2014).
Under the FIFRA, the EPA administrators also take into account the economic, social and environmental costs and benefits of the pesticide.
The EPA dictates what procedures and data are required to evaluate the risk–benefit ratio of a pesticide and provides guidance in determining whether a pesticide causes unreasonable adverse effects.
The results of these risk–benefit analyses are then published together with the EPA’s proposed regulatory decision, followed by the comments of stakeholders. If the pesticide is classified as destined for cancellation or restricted use, the US Department of Agriculture and the EPA’s Scientific Advisory Panel are requested to review the risk–benefit analyses before the final regulatory decision.
After registration of a pesticide, the registrant is still required to inform the EPA of any “additional factual information regarding unreasonable adverse effects on the environment”.
The information that a registrant must submit consists of: toxicological and epidemiological studies, data on pesticide residues in foods and/or the environment, reports of adverse effects and other information of interest in assessing the desirability of continued registration. The registrants will be convicted of a violation if they do not report the required information.
Suspension and Cancellation
The EPA may reconsider the registration of a particular pesticide if new evidence of potential adverse effects emerges. The EPA has authority to restrict, suspend or cancel a pesticide’s registration.
A decision to cancel or suspend a pesticide also depends on the results of cost–benefit analyses focusing particularly on the impact of the cancellation on the production and price of agricultural commodities, retail food prices and other economic factors.
Before deciding to cancel or suspend a pesticide’s registration, an administrator must consider restricting its use. If restriction is deemed unfeasible, the EPA will cancel the pesticide and provide a full justification for its action.
In the United States, the labelling and use of pesticides are also subject to EPA regulation under the FIFRA. Accordingly, the sale and distribution of any mislabelled pesticide is an illegal action.
In addition to directions for use, a pesticide’s label must contain a statement to the effect that it is safe for human health and the environment. Altering a label or using a pesticide that fails to comply with labelling requirements is prohibited.
The Worker Protection Standard (WPS), which is the United States federal regulation issued to protect people from occupational exposure to agricultural pesticides, contains regulations on pesticide safety training, notification of pesticide application, use of personal protective equipment, field re-entry time restrictions following pesticide application and emergency medical assistance (FERA, 2014).
The EPA is authorized to work closely with state-level pesticide regulatory agencies in conducting inspections to ensure that the regulation is implemented and enforced in agricultural communities.
In the United States, a pesticide is considered suitable for general use if it has no unreasonable adverse effects on the environment when used as indicated on the label. A pesticide is for restricted use if it “may generally cause, without additional regulatory restriction, unreasonable adverse effects on the environment”.
Under the WPS, only a certified applicator or someone supervised by a certified applicator can apply pesticides whose use is restricted, whereas anyone can use non- restricted pesticides. The EPA is authorized to issue certification standards for pesticide applicators to ensure that they are competent in the safe and effective use of pesticides.
In Viet Nam, no equivalent WPS has been designed, and despite the fact that MARD regularly issues a list of pesticides for restricted use, Viet Nam has established no similar requirements for the training or certification of pesticide applicators.
Pesticide Storage and Disposal
In the United States the EPA regulates pesticide storage and disposal for four categories of pesticide users: household consumers, farmers, retailers and commercial applicators.
For each of these groups it provides detailed instructions, but the corresponding state and local laws are often stricter than the federal regulations.
For example, most states have developed programmes whereby farmers can “collect and dispose of pesticides in a safe and simple way at little or no cost”.
Pesticide Importand Export Policy
In the United States the EPA regulates both the import and export of pesticides under the FIFRA (Section 17). However, the FIFRA has been criticized for authorizing the EPA to comprehensively regulate the domestic use of pesticides while neglecting regulation on pesticide exportation.
Although the EPA issued the new export policy for pesticides “to protect public health and the environment from unreasonable adverse effects of pesticides, both domestically and internationally”, the agency still allows companies to export pesticides not registered for use in the United States as long as they fulfil certain labelling and warning requirements.
Moreover, despite a domestic requirement that product package labels be multilingual, exporters are only required to print multilingual labels for shipping containers but not for attachment to the product packages. Therefore, applicators in foreign countries may not have an opportunity to review warning information.
The Conditions of Work in Developing Nations
Most studies on pesticide health impacts and most pesticide risk analyses have been performed with reference to the conditions of highly industrial countries. In many cases, agricultural labor is performed in these countries by migrant workers, immigrants, ethnic minorities and the poor.
National laws and regulations that govern the conditions of work and that restrict how pesticides are used are often inadequately enforced. Nonetheless, the conditions and circumstances in the developing world are generally quite different, and the likelihood of exposure to hazardous pesticides is often much greater:
Pesticide containers are frequently unlabeled or are labeled with information that farmers or agricultural workers cannot read (because they are not in local languages or because of insufficient literacy).
National pesticide regulatory regimes are often very weak and inefficient. They sometimes lack meaningful controls on even the most hazardous pesticides and they frequently lack effective surveillance systems and enforcement mechanisms.
Pesticides are frequently used inappropriately or in the wrong concentrations.
Agricultural workers and small farmers frequently lack training and have little access to necessary information. And even when agricultural workers do know that they are using pesticides inappropriately or unsafely, they often fear the consequences of refusing unsafe work practices or even reporting them. In many cases, especially where casual labor is being used, agricultural workers may have few if any rights that they can exercise.
Necessary protective equipment may not be available, may be poorly maintained, and/or may be inappropriate for climatic conditions, especially in regions that are hot and humid. And even where protective equipment is available, many small farmers may be too poor to purchase them.
In highly industrial countries, reported rates of acute pesticide poisoning in agricultural workers may be more than 18 cases per year for each 100,000 full time workers.
In many developing countries, because of the frequently different conditions and circumstances, the rates of acute pesticide poisoning are almost certainly much higher.
The number of workers employed in agriculture in most developing countries is also much higher. The combination of higher pesticide poisoning rates and larger percentages of the population engaged in agriculture makes pesticide poisoning a much greater health problem in the developing world than in highly industrial countries.
However, because public health priorities often tend to emphasize the health problems and concerns of the industrial world, the problem of health injuries caused by pesticide exposure often receives less attention from the public health community than it should.
Additionally, approaches to the regulation of pesticides often assume that conditions of work and regulatory capabilities in developing countries are similar to those in highly industrial countries, but this frequently is not the case.
Pesticide regulation and administration in developing nations
In many developing countries, once a “Highly hazardous pesticide” (HHP) is imported, it is usually difficult or impossible for the national authorities to effectively enforce laws and regulations that would ensure the pesticide will be used only in accordance with the regulatory guidelines.
In such countries, the responsible regulatory approach should be to prohibit the import and use of such pesticides, and to help farmers identify effective, less-hazardous alternatives.
The international code of conduct on the distribution and use of pesticides
As late as the mid-1980s, a large number of developing country govern- ments, possibly most, still lacked any national pesticide control legislation or regulations. Also at that time, pesticide use, including especially the use of highly toxic pesticide formulations, was increasing in the developing world.
This resulted in rising health injuries from toxic pesticide exposure and led to international concern. In response, the governing body of the Food and Agriculture Organization of the United Nations (FAO) adopted the International Code of Conduct on the Distribution and Use of Pesticides (International Code), an attempt to begin addressing this problem by creating universal standards of conduct for everyone involved in pesticide use and regulation, especially national governments and the pesticide industry.
The International Code has already had a positive impact and has twice been updated to reflect changing circumstances: in 1989 and again in 1992.
Since the Code was first adopted in 1985, many additional governments have established legislation to regulate the distribution and use of pesticides; awareness of the problems associated with pesticide use has grown; and many new and successful Integrated Pest Management (IPM) programs that decrease dependence on pesticides are being implemented.
Nonetheless, problems remain, especially in many developing countries. The preface to the most recent, 1992 version of the International Code states:
Even where national pesticide legislation has been adopted, it is often not widely enforced due to lack of technical expertise and resources Highly hazardous or sub-standard pesticide formulations are still widely sold
End-users are often insufficiently trained and protected to ensure pesticides are handled with minimum risk. The International Code is not perfect.
Compliance is purely voluntary and in 1992 when the most recent version of the Code was approved, FAO was not as clear as it is today about its organizational role in promoting national bans on the importation and use of those hazardous pesticides whose proper management and safe use cannot be consistently ensured under prevailing national conditions.
Nonetheless, the International Code is a very important and positive document that NGOs should be familiar with, especially NGOs in developing countries and countries with economies in transition whose missions include support for public health and/or environmental objectives. After reviewing the International Code, NGOs may wish to take actions such as:
Promoting the full and effective national implementation of the Code and its guidelines
Undertaking national advocacy campaigners to press for national reforms addressing problem areas where national policy or practice falls short of what is called for in the guidelines
Contributing to training in IPM and safe occupational practices in support of improved implementation of the Code
NGOs have additionally been invited to monitor the implementation of the code in their own country and to report their findings to the FAO Director- General in Rome.
Regulations on the general use of pesticides
To avoid creating a menace of contamination of the environment and accumulation of pesticide residues, preference must always be given to pesticides that are less persistent, less volatile, and have a lower toxicity when making pesticide recommendation in agriculture.
If there are no sufficient substitutes for stable and volatile substances, the use of the latter and the conditions of working with them are strictly regulated.
The atmospheric air and water basins may become contaminated as a result of the drifting of pesticide particles in dusting, spraying, and using aerosols, as a result of violation of the rules for fumigation, and of the storage and transportation of pesticides in damaged containers, upon treatments in windy weather, and when soil particles are carried off treated fields.
To avoid the drifting of toxicant particles, aerial dusting, fine-drop spraying, and aerosol treatments are prohibited within a radius of 1,000 m around populated localities, farmsteads, and within a radius of 2,000 m from the shores of fish-farming basins.
Pesticides must not be allowed to enter into the atmosphere air of populated localities in concentrations exceeding the maximum acceptable limits.
It is prohibited to perform spraying, dusting, seed treatment, or bait preparation outdoors if the wind speed exceeds 3 m/s.
Aerial dusting is prohibited if the speed of the wind exceeds2 m/s, fine-drop spraying if it exceeds 3 m/s, and large-drop spraying if it exceeds 4 m/s. to reduce the drift of pesticides in aerial treatments, new formulations of pesticides such as inverted emulsions are being developed.
The aerial treatment with chemicals of areas closer than 1 km to populated localities is prohibited. Aerosls may be used only in a calm weather or with a slight wind (up to 2 m/s). Fumigation is not permitted if the wind’s speed exceeds 7 m/s.
Soil, owing to its high biological activity and certain agrochemical properties (acidity, absorptivity, etc) is characterized by an inactivating ability. But upon the frequent use and large rates of consumption of persistent toxicants, they may accumulate in the soil in considerable amounts.
A limited use of persistent pesticides, a strict observance of the rates of use, and the alteration of pesticides of different groups prevent the accumulation of their residues in the soil. Normalization of the maximum permissible residues of pesticides in the soil makes it possible to control and regulate the circulation of pesticides in nature.
It is strictly prohibited to bury and plough into the soil large amounts of pesticides with the aim of destroying them.
It is prohibited to erect pesticide storage facilities near livestock barns and water basins.
Parks and green planting within the confines of populated localities are treated only with pesticides of a moderate and low toxicity having no unpleasant odour, using surface vehicles and machines.
No pesticides may be used for treatment on the territory of hospitals, schools, kindergarden, or sports grounds.
The entire local population is to be informed about the places, times, and the nature of the chemical treatments in good time prior to the commencement of the operation. This is done in order to allow the inhabitants to take relevant safety measures (stop the grazing of cattle, the flight of bees, and field work, to cover wells, etc)
Warning signs are set up on the treated areas and the zones around them at least 300 m wide. It is prohibited to graze cattle during the time indicated in the instruction for the use of the relevant substance.
It is prohibited to feed fodder contaminated with pesticides to agricultural animals.
In conclusion,measure for public safety are aimed at preventing the contamination of the atmosphere, soil, water sources and food products by toxicants.
The strict observant of the rules for working with pesticides exclude the accidental contact with poisonous chemicals, ensure the protection of human, beneficial animals, birds and beneficial insects from the actions of pesticides.