Atmosphere

Air toxics and indoor air quality in Australia

State of knowledge report
Environment Australia, 2001
ISBN 0 6425 4739 4

Part C: Factsheets (continued)

Phthalates

This fact sheet considers phthalates as a class of chemicals; however, phthalates as a class are not included in the 90 substances reportable to the National Pollutant Inventory. The NPI list includes only dibutyl phthalate (DBP) and di-(2-ethylhexyl) phthalate (DEHP); specific data for these two common phthalates are provide below.

Substance name: Dibutyl phthalate (DBP)
Di-(2-ethylhexyl) phthalate (DEHP)
CASR number: DBP: 84-74-2
DEHP: 117-81-7
Molecular formula: DBP: C16H22O4
DEHP: C24H38O4
Synonyms:

DBP: Di-n-butyl phthalate; n-butyl phthalate; 1,2-benzenedicarboxylic acid dibutyl ester; phthalic acid dibutyl ester; o-benzenedicarboxylic acid, dibutyl ester; benzene-o-dicarboxylic acid di-n-butyl ester; dibutyl 1,2-benzenedicarboxylate; benzenedicarboxylic acid, dibutyl ester; dibutyl o-phthalate.
DEHP: 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, di(2-ethylhexyl)orthophthalate, di(2-ethylhexyl)phthalate, di-sec-octyl phthalate, dioctyl ester, dioctyl phthalate

Physical and chemical properties

Both dibutyl phthalate (DBP) and di-(2-ethylhexyl) phthalate (DEHP) are colourless liquids. DBP is an oily liquid with a weak odour. DEHP has almost no odour.

DBP

Melting point: 35°C
Boiling point: 340°C
Density/specific gravity: 1.043
Vapour density: 9.6

DEHP

Melting point: 50°C
Boiling point: 230°C at 5mm Hg
Density/specific gravity: 0.9861 at 20°C
Vapour pressure: 1.32 mm Hg at 200°C
Vapour density: 16 (air=1)

DBP is soluble in most organic solvents, but only slightly soluble in water. The flashpoint is 171° Celsius. DEHP is insoluble in water, miscible with mineral oil and hexane, and soluble in most organic solvents.

Common uses

Phthalates are manufactured chemicals that are commonly added as plasticisers to make plastics more flexible.

DBP is also used in elastomers, lacquers, explosives, printing inks, resin solvents, perfume oil solvents, paper coatings, adhesives, and nail polish. It is used as a solid rocket propellant.

DEHP is primarily used 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 reportedly been used as a replacement for polychlorinated biphenyls (PCBs) in dielectric fluids for electric capacitors and in vacuum pumps.

Sources of emissions

Point sources

The primary sources of phthalate emissions are the industries that manufacture or use them in the production of chemicals and plastics. DBP is also released from the manufacture of machinery and millwork. These emissions are primarily to the air, with a small percentage to the water and land.

Diffuse sources

DBP may be released from commercial and household use, disposal of paints and varnish, and manufacture of plastic parts and carpet backing. DEHP is distributed widely in the environment because of its diffuse use, volatility and persistence.

Natural sources

Phthalates may be produced naturally by some animals and plants, and by small organisms in soils.

Mobile sources

None expected.

Consumer products that may contain phthalates

DBP may be found in colognes and perfumes, cosmetics, paints undercoats and primers, plastic products, floor polish, window cleaning products, caulks and sealants, latex-type adhesives, resin and rubber adhesives, safety glass, vinyl floors, hairspray and nail polish.

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 in medical product containers (including those for blood) and equipment. It is also used in some inks, pesticides, cosmetics and vacuum pump oil.

Health effects

How might I be exposed to phthalates?

DBP is used extensively throughout society and can now be found throughout the environment. Most people are exposed to low levels of DBP in air, water, and food. Levels in city air are 0.03–0.06 ppb. In drinking supplies DBP is found at 0.1–0.2 ppb. At these low levels, DBP is not expected to cause any harmful effects. The largest source of exposure is from food. Certain types of food, especially fish and shellfish, may absorb larger quantities of DBP (50–500 ppb). Some of the DBP in food is from plastics used to wrap and store the food. However, plastic wraps produced in Australian are understood to no longer contain DBP.

Exposure to DEHP may come from the use of medical products packaged in plastic (eg blood products, particularly when used extensively, such as for kidney dialysis); from eating some foods packaged in certain types of plastics or coated papers (especially fatty foods like milk products, fish and seafood); from soils; or from 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).

Exposure at higher levels may occur in a number of ways; workers in industries that use or produce DBP are at risk of exposure. Consumers can be exposed to higher levels of DBP by exposure to air from production and processing facilities using DBP.

By what pathways might phthalates enter my body?

Phthalates can enter the body when a person breathes air containing them, or when a person drinks water or eats food that has been contaminated with these compounds. Phthalates can enter the body through the skin, but this is very slow.

Health guidelines

According to the NOHSC exposure standards for atmospheric contaminants in the occupational environment, it is allowable for workers to be exposed to concentrations of DBP of 5 mg/m³ air over an eight-hour workshift.

For DEHP the time weighted average (TWA):is 5 mg/m³; the short-term exposure limit (STEL) is 10 mg/m³.

What effect might phthalates have on my health?

The effects of inhaling high levels of DBP include irritation of the eyes, nose and throat. DBP may cause nausea, tearing of the eyes, vomiting, dizziness, and headache. Based on animal studies long-term exposure may cause liver and kidney damage. DBP may harm the developing foetus and the male testes.

There is no evidence that DEHP causes serious health effects in humans. Most of what we know about its health effects comes from high exposures of rats and mice to DEHP, 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 and the ability to reproduce, and in birth defects. Kidney damage similar to the damage seen in the kidneys of long-term dialysis patients has also been observed.

Whilst DEHP had previously been classified as a potential human carcinogen, IARC recently downgraded the DEHP classification from Group 2B to Group 3 – not classifiable as to human carcinogenicity to humans. This downgrade was based on the IARC assessment which found that the mechanism by which DEHP increases the incidence of tumours in rats and mice was not relevant to humans.

DEHP is one of a range of phthalates that have been suggested as possible endocrine disruptors (able to affect human and animal endocrine systems).

Environmental effects

Environmental fate

DBP enters the environment during production and use. In the air, it will break down into other chemicals in approximately 1½ days. In water, it will be broken down into other chemicals in 2–20 days.

DEHP occurs in the atmosphere 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 thought to be removed from the atmosphere in 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 does not break down easily in deep soil, or in lake or river bottoms. It is found in plants, fish and other animals, but animals high on the food chain can break it down so tissue levels are usually low.

Environmental transport

Industrial emissions of DBP can produce elevated concentrations in the atmosphere around the source. Since DBP breaks down quickly in the air, high levels are not likely to spread far from where it is used. DBP may be transported through the environment in the water and the tissues of fish and shellfish.

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 the food chain, though it will ultimately be broken down. It does not tend to bioaccumulate, though the concentration of DEHP in fish is probably much higher than the concentration in water in which the fish live. 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.

Environmental guidelines

Australian Water Quality Guidelines for Fresh and Marine Waters (ANZECC 1992):

What effect might phthalates have on the environment?

DBP will exist as both a gas and a particle if released to the atmosphere. It also will be found in soil and water. DBP is highly toxic to aquatic life. The toxicity of DBP to plants, birds, and land animals has not been determined. DBP will bioaccumulate in the tissues of fish and shellfish.

The wide use and distribution of DEHP, as well as its high volatility and persistence, lead to its common occurrence in fish, water and sediments. DEHP has low long-term and short-term toxicity to aquatic life. There is not enough information to evaluate or predict the long-term and short-term effects of DEHP to plants, birds or land animals.

Key

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