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3-(3,4-Dchlorophenyl)-1,1-dimethylurea, Direx, Karmex, Dichlorfendim

SPRI Emission Reporting Threshold
0.05 Kg/yr Pollutant Emissions to Water
0.05 Kg/yr Pollutant Emissions to Waste Water
1.00 Kg/yr Pollutant Emissions to Land
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?
Under normal conditions, Diuron is white crystals which do not have a smell. It melts at 158 degrees celsius. When heated, mixed with hot water or when in acidic or alkaline solution, it rapidly breaks down. Diuron is soluble in water and some organic (carbon-containing) solvents.
What is it used for?
Diuron is a herbicide which is applied to agricultural land before crops emerge or to other land for general weed control. It works by interfering with the way in which the plants generate energy from nutrients and sunlight (photosynthesis).
Where does it come from?
Most Diuron is released to the environment through its application as a herbicide. Some may also be released during its manufacture, transport and storage. There are not thought to be any natural sources of Diuron to the environment.
How might it affect the environment?
Diuron is classed as highly toxic to aquatic organisms. Other forms of wildlife may also be harmed following exposure to high levels, but they are not so sensitive. In shallow surface waters, Diuron will be broken down by sunlight in a matter of days. In the atmosphere, it will also be broken down within a few days. However, Diuron binds strongly to soils and sediments in water bodies and can take from months to years to break down. It is not considered likely that Diuron pollution has any effects on the global environment.
How might exposure to it affect human health?
Diuron can enter the body either by inhalation of air containing diuron, accidental ingestion of diuron, or by dermal contact with diuron. Inhalation of diuron can irritate the nose and throat. Ingestion of diuron may lead to nausea, vomiting and diarrhoea. Dermal contact with diuron can cause skin irritation. Eye contact can cause irritation. The International Agency for Research on Cancer has not designated diuron in terms of its carcinogenicity. However, exposure to diuron 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 Diuron are controlled through the Food and Environmental Protection Act (FEPA 1985), the Control of Pesticides Regulations (COPR 1986), the UK Pollution, Prevention and Control (PPC) Regulations and the UK Surface Waters (Dangerous Substances) Regulations (SI 1997/2560). It is approved for authorised use as a pesticide in the UK (including Scotland) in the Pesticide Safety Directorate. It is also regulated through the European Directive concerned with pollution of the aquatic environment (76/464/EEC), that concerned with levels of pesticide residues in foods (93/58/EC) - which in Scotland is implemented by the Maximum Levels in Crops, Foods and Feedstuffs regulations (MRL 2000) - and it is listed as a "priority substance" in the Water Framework Directive. It is likely that future European legislation will phase out the use of Diuron over the next twenty years. At an international level, Diuron releases are controlled through the OSPAR Convention which protects the marine environments of the north-east Atlantic Ocean.