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Chlorpyrifos

O,O-diethyl-(3,5,6-trichloro-2-pyridinyl)phosphoroioate, Dursban, Lorsban, "Destroyer", "Strike"

SPRI Emission Reporting Threshold
0.1 Kg/yr Pollutant Emissions to Water
0.1 Kg/yr Pollutant Emissions to Waste Water
1.00 Kg/yr Pollutant Emissions to Land
Disclaimer
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?
Chlorpyrifos is found as white crystals which have a strong smell. It melts at 43 degrees celsius. It is not very soluble in water, but dissolves well in organic (carbon-containing) solvents.
What is it used for?
Chlorpyrifos has been widely used as a pesticide since the 1960s. Up until 1997 when its manufacturers voluntarily withdrew it for domestic use, it was used in the home and for pets to control cockroaches, ticks and fleas. Farmers use it mixed with an oily liquid or in capsule form to control parasites on cattle and pests amongst crops.
Where does it come from?
Chlorpyrifos has been released to the environment through its widespread use as a pesticide in domestic, agricultural and commercial situations. Releases may also occur from accidental spills during its manufacture, transport and storage. There are not thought to be any natural sources of Chlorpyrifos to the environment.
How might it affect the environment?
The majority of Chlorpyrifos is applied to land. It binds strongly to soil particles and so is unlikely to seep into water bodies. Chlorpyrifos may kill some birds and non-target insects such as bees. It is also extremely toxic to aquatic organisms, but only relatively small amounts enter surface waters and, since it does not dissolve well, most eventually evaporates from the surface. Chlorpyrifos in soil, air or water is broken down by various processes - sunlight, bacterial action and chemical decomposition. It is not considered likely that Chlorpyrifos pollution has any effects on the global environment.
How might exposure to it affect human health?
Chlorpyrifos can enter the body either by inhalation of air containing chlorpyrifos, ingestion of contaminated food or by dermal contact with chlorpyrifos. Inhalation of air containing chlorpyrifos may result in a number of adverse health effects including headaches, blurred vision, runny nose, lacrimation, dizziness, nausea, and changes in heart rate. Ingestion of chlorpyrifos may cause effects including dizziness, fatigue, runny nose, irritation of the intestine, vomiting, diarrhoea and changes in heart rate. Exposure to high levels of chlorpyrifos can cause faecal incontinence, seizures, coma and death. Dermal contact with chlorpyrifos can lead to skin irritation and can cause skin burns. The International Agency for Research on Cancer has not classified chlorpyrifos in terms of its carcinogenicity to humans. However, exposure to chlorpyrifos 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 Chlorpyrifos are controlled through the UK Pollution, Prevention and Control (PPC) Regulations and the UK Surface Waters (Dangerous Substances) Regulations (SI 1997/2560). Chlorpyrifos 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 Chlorpyrifos include that which controls pollution of the aquatic environment by dangerous substances (76/464/EEC) and it is also listed as a "priority substance" for action under the Water Framework Directive. At an international level, Chlorpyrifos is listed as a candidate substance for inclusion under the OSPAR Convention which is concerned with the protection of the marine environment of the north-east Atlantic Ocean.