Written by Melanie Bateman, CABI
There are many different ways in which pesticides can potentially cause harm to human health or to the environment. For example, substances which are acutely toxic can knock someone down rather rapidly, with symptoms felt within a short space of time. Chronic toxicity, on the other hand, can lead to effects which develop slowly following long and continuous exposure to low concentrations of a hazardous pesticide. Potential consequences of chronic exposure include health problems such as birth defects, developmental issues, cancers, etc. Pesticides can also impact non-target organisms such predators, pollinators, soil biota and aquatic organisms.
Of course, pesticides are not all the same. The degree to which a product is hazardous differs from pesticide to pesticide. Some products are generally not harmful whereas certain pesticides are highly hazardous. A relatively small group of highly hazardous pesticides is often the cause of the majority of poisoning cases.
The FAO and WHO have recently published a set of guidelines (Guidelines on Highly Hazardous Pesticides) which can be used to identify highly hazardous pesticides (HHPs). HHPs are pesticides that are acknowledged to present particularly high levels of acute or chronic hazards to health or the environment according to internationally accepted classification systems. Pesticides that cause severe or irreversible harm to health or the environment under the conditions of use in a country may also be considered highly hazardous. The specific criteria for identification of HHPs are listed in the box below.
The Guidelines on Highly Hazardous Pesticides go beyond identification of HHPs; this document also offers practical steps on how to address them. The Guidelines describe how to carry out risk assessments; guidance is provided on how to take stock of how HHPs are being used and the availability of alternatives; and the Guidelines list mitigation measures which can be put in place to manage risks associated with HHPs. With these Guidelines, countries have a road map for identifying and dealing with highly hazardous pesticides.
Highly hazardous pesticides have one or more of the following characteristics:
Criterion 1: Pesticide formulations that meet the criteria of classes Ia or Ib of the WHO Recommended Classification of Pesticides by Hazard; or
Criterion 2: Pesticide active ingredients and their formulations that meet the criteria of carcinogenicity Categories 1A and 1B of the Globally Harmonized System of Classification and Labelling of Chemicals (GHS); or
Criterion 3: Pesticide active ingredients and their formulations that meet the criteria of mutagenicity Categories 1A and 1B of the Globally Harmonized System of Classification and Labelling of Chemicals (GHS); or
Criterion 4: Pesticide active ingredients and their formulations that meet the criteria of reproductive toxicity Categories 1A and 1B of the Globally Harmonized System of Classification and Labelling of Chemicals (GHS); or
Criterion 5: Pesticide active ingredients listed by the Stockholm Convention in its Annexes A and B, and those meeting all the criteria in paragraph 1 of Annex D of the Convention; or
Criterion 6: Pesticide active ingredients and formulations listed by the Rotterdam Convention in its Annex III; or
Criterion 7: Pesticides listed under the Montreal Protocol;
Criterion 8: Pesticide active ingredients and formulations that have shown a high incidence of severe or irreversible adverse effects on human health or the environment.
For more information on the recommendation of pesticides within the Plantwise programme, please see the Plantwise Red List of restricted chemicals.