Pesticides – Highly Hazardous

Unique identifier / Notation

CH0008

Synonyms

Not identified.

Pesticide means any substance, or mixture of substances of chemical or biological ingredients intended for repelling, destroying or controlling any pest, or regulating plant growth. Pesticides are inherently toxic, and among them, a small number of Highly Hazardous Pesticides, cause disproportionate harm to the environment and human health. The Food and Agriculture Organization (FAO) and the World Health Organization (WHO) Guidelines on Highly Hazardous pesticides (UNEP, 2021) adopted the following definition:

“Highly Hazardous Pesticides means pesticides that are acknowledged to present particularly high levels of acute or chronic hazards to health or environment according to internationally accepted classification systems such as WHO or Global Harmonized System (GHS) or their listing in relevant binding international agreements or conventions. In addition, pesticides that appear to cause severe or irreversible harm to health or the environment under conditions of use in a country may be considered to be and treated as highly hazardous.”

Primary reference(s)

UNEP, 2021. Highly Hazardous Pesticides (HHPs). Accessed 7 May 2021.

Additional scientific description

Pesticides can also be grouped according to the types of pests which they kill: insecticides (insects); herbicides (plants); rodenticides (rodents); bactericides (bacteria); fungicides (fungi); and larvicides (larvae).

A pesticide is considered to be highly hazardous if it has one (or more) of the following characteristics:

High acute toxicity
Long-term toxic effects at chronic exposure
High environmental concern either through ubiquitous exposure, bioaccumulation or toxicity
Known to cause a high incidence of severe or irreversible adverse effects on human health or the environment (Pesticide Action Network, 2009).

Internationally accepted classification of highly hazardous pesticides

Criterion 1: Acute Toxicity – WHO Recommended Classification of Pesticides by Hazard Classes Ia or Ib.
Criteria 2–4: Chronic Toxicity
- GHS Carcinogenicity Categories 1A and 1B
- GHS Mutagenicity Categories 1A and 1B
- GHS Reproductive Toxicity Categories 1A and 1B.
Criterion 5: Stockholm Convention – Pesticides listed in Annexes A and B.
Criterion 6: Rotterdam Convention – Pesticides listed in Annex III.
Criterion 7: Montreal Protocol – Pesticides listed.
Criterion 8: High incidence of severe or irreversible adverse effects (WHO, 2019).

Metrics and numeric limits

Available data are too limited to estimate the overall global health impacts of pesticides; however, the global impact of self-poisoning (suicides) from preventable pesticide ingestion was estimated to be 155,488 deaths and 7362,493 Disability Adjusted Life Years (DALYs) for 2016 (WHO, 2019).

The WHO provides maximum residue limits (MRLs) for pesticides in food and levels in drinking-water as follows (WHO, 2019):

Maximum residue limits in food: The Joint Food and Agriculture Organization of the United Nations (FAO) / WHO Meeting on Pesticide Residues (JMPR) evaluates those pesticides likely to contaminate food. MRLs are published by the Codex Alimentarius Commission. Guidance for individual pesticides or pesticide components – including for a number of highly hazardous pesticides – can be accessed via the FAO, WHO, Codex Alimentarius Commission or National Framework for Chemicals Environmental Management (INCHEM) websites and in hard-copy publications.
Drinking-water: WHO water quality guidelines exist for some pesticides used in agriculture and public health – including for some highly hazardous pesticides – where there is a likelihood of drinking-water contamination.

Key relevant UN convention / multilateral treaty

The Stockholm Convention on persistent organic pollutions (POPs) (UNEP, 2001). At the time of writing, there were 183 parties.

The Rotterdam Convention on the Prior Informed Consent Procedure for Certain Hazardous Pesticides (1998). At the time of writing there were 161 parties.

The Basel Convention on the Control of Transboundary Movements of Hazardous Wastes and their Disposal (1989). At the time of writing, there were 187 parties.

The Montreal Protocol on Substances that Deplete the Ozone Layer (1987) has been ratified by all 197 UN Member States.

Examples of drivers, outcomes and risk management

Outcomes of exposure to highly hazardous pesticides include (WHO, 2019):

Unintentional and self-inflicted (suicide) acute poisonings by pesticides are a serious public health concern in many parts of the world.
The acute hazard is highly variable depending on the pesticide and includes peripheral and central neurotoxicity and reduced blood clotting capacity. The specific pesticide formulation can significantly affect both exposure and toxicity. Short-term exposure can cause harmful effects on the liver, kidneys, blood, lungs, nervous system, immune system and gastrointestinal tract.
Chronic exposure to highly hazardous pesticides can affect the skin, eyes, nervous system, cardiovascular system, gastrointestinal tract, liver, kidneys, reproductive system, endocrine system, immune system and blood. Some highly hazardous pesticides may cause cancer, including childhood cancer.
Toddlers and children are considered more vulnerable to exposure to pesticides due to their smaller size, hand to mouth activity, different metabolism, and because they are still developing.

Risk mitigation measures are critical. In 2015, the Strategic Approach to International Chemicals Management (SAICM) International Conference on Chemicals Management adopted a resolution that recognised highly hazardous pesticides as an issue of concern and called for concerted action by countries to address these substances, with emphasis on promoting agro-ecologically based alternatives and strengthening national regulatory capacity to conduct risk assessment and risk management (WHO, 2019). Several initiatives undertaken by international organisations, including the WHO/FAO, support this resolution. These include the publication of guidelines to support the International Code of Conduct on Pesticide Management, including those on highly hazardous pesticides, Good Labelling Practice for Pesticides, Pesticide Legislation and other important resources and guidance documentation to assist in the implementation of best practices, which have been brought together in a toolkit (FAO, 2018).

The highly hazardous pesticides risk reduction process consists of three main consecutive steps: identification of highly hazardous pesticides by checking registered pesticides against the FAO/WHO criteria; assessment of highly hazardous pesticides by assessing each product for risks and needs to determine whether action is desirable; and mitigation of highly hazardous pesticides risks by determining for each product whether risk mitigation measures are required, and if so, which options would be most appropriate (WHO, 2019).

To reduce exposure to highly hazardous pesticides and their health impacts, the WHO summarised actions required in the following areas: handling, storage, use and disposal; elimination and replacement of pesticide use; education; and regulation, monitoring and surveillance (WHO, 2019).