Environmental Information

Plant researchOver the past 40 years the effect of phthalates in the environment has been extensively studied. Research demonstrates that at current and foreseeable exposure levels they do not pose a risk to the environment.

Improved analytical techniques have enabled more reliable measurements to be made of the level of phthalates in a very wide range of water, sediment, soil, plant and animal samples. These are being used to raise the quality of the ongoing risk assessments by calibrating and improving the models used.

It has been demonstrated that phthalates are widely distributed in the environment but that their levels are low because they are subject to relatively rapid photochemical and biological degradation.  In addition their levels are falling because of the increasing use of water treatment plants.

Phthalates do not accumulate in water

Although phthalates are widely distributed in the environment, their levels are low because they are subject to rapid photochemical and biodegradation. In fact, levels of phthalates in natural waters are reported to be decreasing.1,2

The Netherlands National Institute of Public Health and Environmental Protection (RIVM) has reported that the level of phthalates in Lake Yssel fell by 75% in the period 1980-88.3

Phthalates can accumulate in some simple, aquatic organisms. However, most higher organisms (such as fish) are able to metabolise them (or break them down) rapidly without apparent harm. Therefore, biomagnification up the food chain does not occur.

In addition, most phthalates at concentrations up to their limits of solubility in water do not exibit acute or chronic toxicity to a variety of aquatic organisms. 4,5

Phthalates do not enter the human food chain

It has been suggested that the spreading of municipal sewage sludge on agricultural land could lead to phthalates being taken up by plants and entering the human food chain. However this subject has been comprehensively studied over the years and there is no evidence to suggest that phthalates can enter the human food chain in this way.

There are two points to bear in mind: the rates at which phthalates biodegrade in sewage sludge and soils; and the uptake by plants from the ground of phthalates such as di-2-ethylhexyl phthalate (DEHP). Phthalates are subject to both aerobic and anaerobic (in the presence, or not, of oxygen respectively) biodegradation. There are several investigations which demonstrate that when they are contained in sewage sludge they are rapidly biodegraded.

For example, one study6 examined garden soil containing DEHP Within 20 days 75% of phthalate levels had been degraded and after 30 days the figure was more than 90%.

A major research study on the uptake by plants of DEHP was conducted in the United States in 1989.7 Among the plants grown and tested were four food chain crops: lettuce, carrots, chilli peppers and tall fescue (a pasture grass). The authors concluded that "...because intact DEHP was not detected in any plants, DEHP uptake by plants was of minor importance and would not limit sludge additions to soils used to grow these crops".

Phthalates don't mimic natural oestrogens and there is no evidence to suggest that their presence in the environment reduces sperm counts in humans or wildlife

There have been reports of reduced sperm counts in men and it has been hypothesised that this may be due to exposure to chemicals in the environment which mimic the natural female hormone oestrogen. There is still no evidence that there is a general problem in humans and no evidence that chemicals in general, or any chemicals specifically, are the cause.

With regard to phthalates, the most recent in-vivo (live experimentation) studies specifically intended to look for oestrogenic effects have shown 8,9,10 that all the phthalates ranging from dibutyl phthalate (DBP) to diisodecyl phthalate (DIDP) produce no oestrogenic effects.

The hypothesis of the potential impact of industrial chemicals on the environment is a question for the entire chemical industry. Cefic, the body which represents the European chemical industry, has responded to this broad debate and has already implemented a substantial programme of research.

References

  1. Furtmann, K., (1993), 'Phthalate in der aquatischen Umwelt', Landesamt für Wasser und Abfall, NordrheinWestfalen, No6/93.
  2. Hurford N., Law, RJ, Payne, AP, Fileman, TW, (1989), Oil. Chem. Pollut 5, 391-410
  3. National Institute of Public Health and Environmental Protection (RIVM), 'Update of the Exploratory Report Phthalates', report no 710401008, Netherlands, 1991.
  4. Rhodes, JE, Adams, WJ, Biddinger, GR, Robillard, KA and Gorsuch, JW, (1995), Env. Toxicol. and Chemistry, 14, 11, 1967.
  5. Adams, WJ, Biddinger, GR, Robillard, KA and Gorsuch, JW, (1995), Env. Toxicol. and Chemistry, 14,9,1569.
  6. Shanker, R., Ramakrishna, C. and Seth, PK., (1985), 'Degradation of some phthalic acid esters in soil', Environ. Poll., 39, 1-7.
  7. Aranda, JM, O'Connor, GA and Eiceman, GA, 'Effects of sewage sludge on di-(2-ethyihexyl) phthalate uptake by plants', (1989), J Environ. Qual. 18, 45-50
  8. Meek M D, Clemons J, Wu Z F and Zacharewski T R (1996), 'Assessment of the alleged oestrogen receptormediated activity of phthalate esters', presented at the 17th Annual SETAC Meeting, Washington, USA, 18-21 November 1996.
  9. Meek, MD, Clemons, J, Wu, ZF and Zacharewski, TR., (1997), 'Examination of the alleged in-vitro and in-vivo ostrogenic activities of eight commercial phthalate esters', Presented at the SETAC Europe Meeting, Amsterdam, 6-10 April 1997. Submitted for publication.
  10. Uterotrophic assays in immature rats, Zeneca Central Toxicology Laboratory, Report Nos. CTL/R/1278-1281, 1996.