DEHP is a manufactured chemical that makes plastic more flexible. Its primary use is as one of several plasticisers in polyvinyl chloride resins used for fabricating flexible vinyl products. It is used to detect leaks in protective face gear, and as a test material for filtration systems. It has also been reported as being used as a replacement for polychlorinated biphenyls (PCBs) in dielectric fluids for electric capacitors and in vacuum pumps.
Substance name: Di-(2-Ethylhexyl) phthalate (DEHP)
CASR number: 117-81-7
Molecular formula: C24H38O4
Synonyms: 2-benzene-dicarboxylate, 2-Ethylhexyl phthalate, BEHP, Bis(2-ethylhexyl)-1, Bis(2-ethylhexyl) ester, Bis(2-ethylhexyl)phthalate, Bisoflex 81, Bisoflex DOP, Compound 889, DAF 68, DEHP, Di(2-ethylhexyl)orthophthalate, Di(2-ethylhexyl)phthalate, Di-sec-octyl phthalate, dioctyl ester, Dioctyl phthalate, DOP, Ergoplast FDO, Ethylhexyl phthalate, Eviplast 80, Eviplast 81, Fleximel, Flexol DOP, Flexol plasticizer DOP, Good-Rite GP 264, Hatcol DOP, Hercoflex 260, Kodaflex DOP, Mollan O, NCI- C52733, Nuoplaz DOP, Octoil, Octyl phthalate, Palatinol AH, Phthalic acid, Pittsburgh PX-138, Platinol DOP, RC Plasticizer DOP, RCRA waste number U028, Reomol D 79P, Reomol DOP, Sicol 150, Silicol 150, Staflex DOP, Truflex DOP, Vestinol AH, Vinicizer 80, Witcizer 312
DEHP is a colourless liquid with almost no odour.
Boiling Point: 230°C at 5 mm Hg
Melting Point: -50°C
Vapour Density: 16
Density/Specific Gravity: 0.9861 at 20/20°C
Vapour Pressure: 1.32 mm Hg at 200°C
DEHP is insoluble in water, miscible with mineral oil and hexane, and soluble in most organic solvents.
The National Pollutant Inventory (NPI) holds data for all sources of Di-(2-Ethylhexyl) phthalate emissions in Australia.
There is no evidence that DEHP causes serious health effects in humans. Most of what we know about the health effects of DEHP comes from high exposures to rats and mice which may not be representative of the effects on humans. In general effects observed in animals were only from very high and prolonged doses. Exposure to DEHP in air did not result in any observed effects. Exposure in food and water resulted in effects on sperm production, the ability to reproduce and birth defects. Kidney damage similar to the damage seen in the kidneys of long-term dialysis patients has also observed.
DEHP has been classified as a potential carcinogen.
DEHP is one of a range of phthalates which have been suggested as being able to be effect human and animal endocrine systems (endocrine disruptors).
Entering the body
It is possible for DEHP to enter the body by breathing the vapours or by ingesting it directly or through products contaminated by it. Absorption through skin contact is also possible but only very slowly.
Exposure may come from use of medical products packaged in plastic such as blood products (particularly when used extensively, such as for kidney dialysis) eating some foods packaged in certain types of plastics or coated papers (especially fatty foods like milk products, fish and seafood), soils, drinking contaminated water or breathing air containing DEHP where it is used or spilled. Indoor concentrations may be higher because of the presence of products that may emit DEHP (eg plastics).
Workplace exposure standards
Safe Work Australia sets the workplace exposure standard for di-(2-Ethylhexyl) phthalate (DEHP) through the workplace exposure standards for airborne contaminants:
- Maximum eight hour time weighted average (TWA): 5 mg/m3
- Maximum short term exposure limit (STEL): 10 mg/m3
These standards are only appropriate for use in workplaces and are not limited to any specific industry or operation. Make sure you understand how to interpret the standards before you use them.
Drinking water guidelines
The Australian Drinking Water Guidelines include the following guidelines for acceptable water quality:
- Maximum of 0.01 milligrams per litre of water for health purposes
DEHP in the atmosphere is present either as a gas or attached to solid particles. The gas breaks down relatively quickly ( 1 or 2 days) due to the action of other chemicals in the atmosphere. The solid particles are estimated to be removed from the atmosphere in a period of two to three weeks by various mechanisms including precipitation, wash out by rain and reaction with other chemicals. DEHP is slightly persistent in the environment. Small organisms in surface water or soil break it down into harmless compounds. It doesn't break down easily in deep soil, or in lake or river bottoms. It is in plants, fish, and other animals, but animals high on the food chain are able to breakdown DEHP, so tissue levels are usually low.
Phthalate is slightly persistent in water but will break down in a few months.
Entering the environment
DEHP from plastic materials, coatings, and flooring can increase indoor air levels. It dissolves faster in water if gas, oil, or paint removers are present. DEHP in the particle-phase is subject to wet and dry deposition. It will be transported in food chain though it will ultimately be broken down and does not tend to bioaccumulate though the concentration of DEHP in fish is expected to be much higher then the concentration in water in which the fish live.
Where it ends up
About 42.8% of DEHP will eventually end up in terrestrial soil; about 40% will end up in aquatic sediments; and about 17% will end up in air.
Australian Water Quality Guidelines for Fresh and Marine Waters (ANZECC, 1992):
Maximum 0.6 micrograms per litre (ie 0.0000006g/L) in fresh water.
Point sources are primarily from emissions or spills from sites that use DEHP in their manufacturing processes.
Diffuse sources, and industry sources included in diffuse emissions data
It wide use, volatility and persistence mean that DEHP is widely distributed in the environment.
DEHP has been suggested as a possible natural product in some animals and plants.
DEHP is in polyvinyl chloride (PVC) plastic products like toys, vinyl upholstery, shower curtains, adhesives, and coatings. It is used in some food packaging, and medical product containers (including those for blood) and equipment. It is also used in some inks, pesticides, cosmetics, and vacuum pump oil.
Sources used in preparing this information
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- Australian and New Zealand Environment and Conservation Council (ANZECC) (1992), Australian Water Quality Guidelines for Fresh and Marine Waters.
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- Safe Work Australia, Workplace exposure standards for airborne contaminants, accessed September 2018.
- National Health and Medical Research Council (NHMRC), Australian Drinking Water Guidelines (2011) - Updated October 2017, accessed May 2018