When historians look back at the last century, two products – plastics and transistors – will stand out as having changed how we live and which, each in their own way, have affected our well being. Phthalates (pronounced thall-ates) are a group of industrial chemical compounds with a multitude of uses. They are mainly used as plasticizers – that is, as substances added to plastics to increase their flexibility; to turn a hard plastic such as polyvinyl chloride into a flexible plastic. They are also used as solubilizers and stabilizers. The name phthala-te is derived from phthalic acid together with the suffix ‘ate’, which indicates that something is ‘full of’ or ‘showing’. Phthalic acid is also known as benzene dicarboxylic acid. Phthalates are considered environmental and biomedical pollutants because of their toxic properties.
Exposure to phthalates
About one billion pounds or 400,000 tons of phthalates are produced annually, with di-2-ethyl hexyl phthalate (DEHP) being the most widely used. While DEHP is used in a number of products, about 95% is used in polyvinyl chloride (PVC). PVC has replaced clay, wood and concrete as a cheap and easily assembled building material, but the human and environmental costs are yet to be fully determined.
Phthalates are used in diverse products from flooring to cosmetics. Phthalate esters are found in surprising places, from vinyl gloves that can leach the harmful chemical into foods during handling to the non-stick coatings used in cookware. They are used in cosmetics, particularly in perfumes to make the fragrance linger for longer than normal; and in nail polish to prevent chipping and when rapid setting and stain resistance is required. Used in lacquers, paints, dyes, caulk, pesticides, and insect repel-lants, they are also used in solid rocket propellants, as flame retardants and textile lubricating agents. They can be found in everyday household products as well as in automobiles and pesticides. They are, in fact, ubiquitous. See Figure 1 and Figure 2 for a partial list of commonly used phthalates and sources of phthalates respectively.
|Abbreviations for Some Phthalates|
|DEHP||di-2-ethyl hexyl phthalate|
|Partial List of Sources of Phthalates|
|after shave lotions||fragrances||polyurethane|
|air fresheners||garden hoses||processed food|
|artificial leather||gels||rain gear|
|automotive parts||glues||recycled PVC products|
|biomedical devices||grocery bags||rocket propellants|
|body care products||hair products||rubber coatings|
|car seats||insect repellants||scented candles|
|car interiors||kitchen utensils||sewage sludge|
|carpet tiles||lacquers||sexy toys|
|carpet rubber underlay||lotions||shampoos|
|caulk||lubricants||skin care products|
|cellulose plastics||medical equipment||solvents|
|cigarettes||medical products**||stain resistant products|
|clothing||nail polish||swimming pool liners|
|color stabilizers||non-stick coatings||textile lubricants|
|denture linings||paint binders||vinyl products‡|
|deodorants||paper coatings||wall coverings|
|film coating||perfumes||waterproof coatings|
|food*||personal care products||wound disinfection solutions|
|food packaging||personal lubricants|
|flame retardant fabrics||plastics bags|
* Stored in plastic and/or handled with rubber or vinyl gloves
** medical products such as blood, intravenous and dialysis bags, catheters, tubing
† agricultural land to which sewage sludge has been added or soil containing decomposing garbage that includes plastic products
‡ vinyl tiles, vinyl binders, shower curtains, bags, footwear, etc.
Cosmetics and personal care products have been found to contain phthalates. A 2002 study of the $20-billion cosmetic industry by the Environmental Working Group1 found that 52 of the 72 products tested contained phthalates; yet, none listed the phthalate on the ingredient label. Because phthalates are considered part of trade secret formulas, they are exempt from federal labelling requirements and as such cosmetic companies may use any quantity in their products without any necessity of testing, labeling or determination of health effects.
A recent study by Liang2 found that vinyl flooring and crib mattress covers emit phthalates. Emission rates were found to increase exponentially with temperature increases, so that an increase from 25o to 35oC in a child’s bedroom could see airborne phthaltes increase by more than a factor of 10. An increase in the temperature of the mattress also caused a significant increase in the emission of phthalates from the mattress cover, resulting in the infant being exposed to four times the level of phthalates adjacent to the nose compared with the level in the air. This would result in high exposure to phthalates.
Three types of phthalates appear to be involved in atopic disease. They are butyl benzyl phthalate (BBzP), di-n-butyl phthalate (DnBP) and di (2-ethylhexyl) phthalate (DEHP). BBzP is a plasticizer. More than a million pounds are produced and used annually in the US for use in vinyl tiles, sealants, adhesives, carpet tiles and artificial leather, paint binders, wall coverings, cellulose plastics, rubbers and polyurethane.3 BBzP has been found in pillow protectors, dryer sheets, polishes, waxes, car interior cleaners and in tub/tile cleaners, bar soap, shaving cream and lipstick.4 It is also used to make foam PVC which is converted into flooring material.
DnBP is found in carpets, floor tiles, paint, nail polish, false fingernails, hair spray, skin emollients and other cosmetic products (both as solvent and fixative), latex adhesives, cellulose plastics and as a solvent for certain dyes. It is used as a suspension agent for solids in aerosols and as a lubricant for aerosol valves. It is also an anti-foaming agent. While used in material for storing and packaging food, it can also be found in bowls, shower curtains, vinyl fabrics and car interiors, in lacquers and adhesives, and even as a coating for paper and film.5
DEHP is mainly used as a plasticizer for PVC. It is found in plastic products such as tablecloths, shower curtains, garden hoses, swimming pool liners, and in clothing from baby pants to rain wear. It is also found in upholstery and automobile tops, in packaging for fatty and oily foods (such as milk products, fish, seafood and oils), toys, shoes, air fresheners, dryer sheets, sun screen, and in medical products that are packaged in plastic (such as blood storage bags) and in medical tubing. Its many uses include sheathing for wire and cables. One of its big advantages is that it biodegrades into harmless compounds in soil or water.4, 6
- Houlihan J, Brody C, Schwan B. 2002. Not Too Pretty: Phthalates, Beauty Products, and the FDA. Washington, DC:Environmental Working Group. Available: http://www.safecosmetics.org/downloads/NotTooPretty_report.pdf Retrieved Dec 30, 2014
- Liang Y1, Xu Y. Emission of phthalates and phthalate alternatives from vinyl flooring and crib mattress covers: the influence of temperature. Environ Sci Technol. 2014 Dec 16;48(24):14228-37. doi: 10.1021/es504801x. Epub 2014 Dec 5.
- www.atsdr.cdc.gov/phs/phs.asp?id=857&tid=167/ Accessed Dec 30, 2014
- Dodson RE, Nishioka M et al. Endocrine disruptors and asthma-associated chemicals in consumer products. Environ Health Perspect. 2012; 120(7):935-43. DOI:10.1289/ehp.1104052
- www.inchem.org/documents/ehc/ehc/ehc189.htm#SubSectionNumber:3.2.2 Retrieved Dec 30, 2014
- www.atsdr.cdc.gov/substances/toxsubstance.asp?toxid=65 Accessed Dec 30, 2014