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2,4-Dichlorophenoxyacetic acid (2,4-D) - ester and non-ester

2,4-D, Amoxane, Cloroxane

SPRI Emission Reporting Threshold
0.1 Kg/yr Pollutant Emissions to Water
0.1 Kg/yr Pollutant Emissions to Waste Water
This sheet is a generic summary, designed to give the reader a basic level of background information about the substance in question. Great care has been taken to represent as effectively and correctly as possible the broad range of (not necessarily consistent) information which is available from a variety of sources. The reader must accept therefore that this sheet has no legal status and cannot be relied upon in any legal proceedings. SEPA disclaims any responsibility or liability whatsoever for errors and omissions in this sheet.
What is it?
Pure 2,4-Dichlorophenoxyacetic acid (2,4-D) is a white, cystalline powder which has no smell and readily dissolves in water. 2,4-D often however contains impurities which can give it a yellow colour and also a smell, the nature of which depends on the impurities.
What is it used for?
2,4-D is one of a group of similar chemicals called chlorophenoxy herbicides. 2,4-D works by interfering with the action of certain plant hormones and is used as a selective weedkiller for a variety of crops.
Where does it come from?
The main releases of 2,4-D occur through its use as a herbicide on commercial crops. Smaller amounts are also released as spills from industry where it is sometimes formed as a by-product in the production of similar chemicals. There are not thought to be any natural sources of 2,4-D to the environment.
How might it affect the environment?
2,4-D released to air breaks down into other substances within a matter of days. In soils, the amount of time taken for it to decompose can be days or weeks, depending on the conditions. 2,4-D decomposes rapidly in sediments and does not bind to them in any significant way. It is however more persistent in water (taking weeks or even months to break down) and, because of its high solubility, run-off following application to soils is very likely to end up in rivers and then groundwaters. Fish exposed to 2,4-D are harmed, but it does not accumulate in aquatic organisms. 2,4-D is not thought to have impacts on the environment at a global level.
How might exposure to it affect human health?
Exposure to 2,4-Dichlorophenoxyacetic acid mainly occurs in the occupational setting and can enter the body either by inhalation of air containing 2,4-dichlorophenoxyacetic acid, ingestion of contaminated food or water, or by dermal contact with 2,4-dichlorophenoxyacetic acid. Inhalation of air containing 2,4-dichlorophenoxyacetic acid can cause irritation of the respiratory tract, headache, nausea, weakness, stiffness in the arms and legs, a lack of coordination, lethargy, and coma. Ingestion of 2,4-dichlorophenoxyacetic acid can lead to gastrointestinal irritation, nausea, vomiting, diarrhoea, headache, unconsciousness, liver and kidney damage and in extreme cases death. Dermal contact with 2,4-dichlorophenoxyacetic acid can cause skin irritation and dermatitis. Absorption of 2,4-dichlorophenoxyacetic acid may result in symptoms similar to those for inhalation and ingestion. Contact with the eyes can cause irritation. The International Agency for Research on Cancer has designated 2,4-dichlorophenoxyacetic acid as a possible carcinogen. However, exposure to 2,4-dichlorophenoxyacetic acid at normal background levels is unlikely to have any adverse effect on human health.
What steps are being taken to limit the potential impacts?
Releases of 2,4-D are controlled through the UK Pollution, Prevention and Control (PPC) Regulations and the UK Surface Waters (Dangerous Substances) Regulations (SI 1997/2560). 2,4-D is also regulated as a pesticide through the Food and Environmental Protection Act (FEPA 1985) and the Control of Pesticides Regulations (COPR 1986). European Directives concerned with releases of 2,4-D include that which controls pollution of the aquatic environment by dangerous substances (76/464/EEC). At an international level, 2,4-D is regulated through the OSPAR and Helsinki Conventions which are concerned with the protection of the marine environment of the north-east Atlantic Ocean and the Baltic Sea respectively.