Scientists have been able to measure phthalate levels in human tissues for just a few years. Studies have shown that most Americans have phthalates in their urine and that all of us are exposed to phthalates from such ubiquitous sources as air, water and soil as well as from foods. People who undergo medical procedures are exposed to especially high levels since phthalates can leach out of plastic medical supplies. Infants have been found to have higher levels than adults.
Studies on phthalates as reproductive toxins in humans are fewer in number, correlational (since you can't manipulate human exposure to a supposed toxin) and very recent. The large number of phthalate compounds & sources of human exposure make absolute conclusions difficult. Nevertheless, the U.S. National Toxicology Program's Center for the Evaluation of Risks to Human Reproduction Expert Panel concluded in 2000 that DEHP has the potential to produce adverse reproductive effects in humans.(11)
Daily human consumption of DEHP from all sources was estimated to be 5.8 mg in 1985 (U.S. Department of Health and Human Services),(12) increasing to the tens of milligrams in a 1994 study.(44) A very recent sample of the general German population revealed that 12% of people were exceeding the "tolerable daily intake" of DEHP as set by the European Union.(47) In infants in intensive care units undergoing medical procedures with disposable PVC medical supplies (e.g. tubing), DEHP exposure can be three orders of magnitude higher than typical adult exposures and can exceed levels known to cause reproductive abnormalities in lab animals. (53) In 2002 the FDA warned that children undergoing certain medical procedures involving PVC medical supplies (such as infants in intensive care units), as well as adults undergoing various medical procedures, such as coronary bypass graft surgery, might be exposed to unsafe levels of DEHP.(61) The National Toxicology Program Center for the Evaluation of Risks to Human Reproduction's expert panel report expressed additional concerns about DEHP exposure to pregnant and breast-feeding women.(11)
Phthalates are ubiquitous in the urine of U.S. adults and children, showing widespread exposure: Not until 2000 has there been a direct way to measure phthalate exposure in humans, so data on humans are very recent. Phthalates were present in urine of more than 75% of the first CDC sample of the U.S. adult population reported in 2001.(16) A subsequent, more detailed study revealed that the youngest age group studied, children 6-11 yrs, had the highest urinary levels of the active metabolites of at least three phthalates, DEHP, DBP and DBzP.62 Compared to other adults, women of reproductive age tend to have the highest levels of the metabolite of DBP; DBP is commonly used in perfumes, lotions and nail polish and is known to be a reproductive toxicant in animals.(16) In 48-hr personal air and urine samples of pregnant women in New York City and Krakow, Poland, 100% of samples contained multiple phthalates; the fact that air and urinary concentrations were correlated indicates that inhalation is an important route of exposure in pregnant women.(30) Even household dust is an important source of phthalate exposure: every dust sample from homes in a Cape Cod study had phthalates including DEHP.(84)
Study in infants 12-18 months old living in the Imperial Valley, CA revealed urinary phthalates (metabolites of DEHP, DBP, DEP, & BzBP) in all infants at levels higher than previously reported in adults.(46) PVC toys are a likely source of the DEHP metabolite MEHP.
The issue of phthalates goes well beyond their use in plastics. Phthalates are also heavily used in drugs, cosmetics & colognes and many other household products.
Cosmetics & colognes
- "Safer Cosmetics Bill" (CA AB 2025) targeting phthalates in cosmetics died in Assembly Health Committee in 2004. It would remove carcinogens and reproductive toxins from cosmetics and require labeling of all ingredients.
- Several phthalates are commonly used in cosmetics but often omitted from the list of ingredients.(50) Beauty products are suspected to be important contributors to the higher urinary levels of two phthalates (DEP and DBP) in women of reproductive age.(16, 51) Women in this age group are among the highest consumers of beauty products, raising concerns given the studies of the toxic reproductive effects of some phthalates.
- Last year the European Union banned phthalates in cosmetics sold there, effective Sept. 2004.(49)
- FDA report (2001) concluded that phthalates are safe in the quantities currently used. FDA has no plans to review safety. However, a few U.S. companies are voluntarily phasing out phthalates (e.g. Estee Lauder, Proctor & Gamble).(49)
- Enteric-coated pills
Some oral medications are coated with phthalates to control when the pills dissolve.(48)
- Other sources
The impact of phthalate exposure from many other known sources, such as insect repellents, paint, pesticides and industrial solvents, has yet to be measured.
- Plastics as carriers of toxins into the human food chain
Plastic resin pellets are lipophylic and can concentrate (onto their surfaces) PCBs and other oily toxins up to one million times the concentrations in the surrounding seawater.(71) Furthermore, marine plastic fragments have been found to outweigh zooplankton by a factor of 2.5 off the California coastline and by a factor of 6 in the North Pacific central gyre.(72, 73) It is reasonable to question the role of plastics ocean debris as transporters of oily toxins into the food chain. This has not been investigated directly. However, we do know that those eating at the top of the food chain, people like the Arctic Inuit who live far from any form of industrialization, have extremely high levels of PCBs and other toxins in their breast milk.(78) And, a just released study from England found that the microscopic breakdown fragments of plastics are now ubiquitous in samples of ocean water and sediments.(79) That study also found increasing levels over time of such tiny plastics particles in previously frozen samples of zooplankton dating back to the 1960s, demonstrating the accumulation of plastics into the bottom end of our food chain. Furthermore, there has been a study showing that levels of phthalates in the semen of infertile men were higher in fish eaters than in vegetarians.(41)
Routes of human exposure to plastic additives
- Microwaving foods (esp. acidic and fatty entrees) in plastic containers
- TV dinners in plastic trays or with plastic film
- Boil-in-bag foods
- Bottled water
- Migration into cheeses/meats, etc, from stretch wrap
- Hospitalization or medical procedures (stents, catheters, IVs, respiratory devices). IV Bags with fatty substances like food or blood contain up to 50% DEHP
- Pacifiers, baby bottles and children's toys
- Cooking with Teflon cookware
- Canned foods lined with plastic lacquer
- Eating fish/meats/dairy products (phthalates in food chain)
- Baby foods and infant formulae
- House dust (e.g. PVC dust from common household vinyls such as flooring)
- Air (e.g. phthalates released from plastic car interiors i.e. that "new car" smell, vinyl flooring)