Public Contamination
Because polystyrene products are so common, many people assume they are safe, and
that a
government agency, such as the Food and Drug Administration (FDA), would not allow a
health-
threatening product to be marketed to the public.[1] But
the
EPA National Human Adipose Tissue Survey for 1986 identified styrene residues in 100% of all samples of human fat tissue
taken
in 1982 in the US. Styrene is used to make polystyrene plastic and is a contaminant in all
polystyrene foam packages.[2] But the migration of styrene
is
nothing new. It was first documented in 1972,[3] and then
again in 1976.[4]
A 1988 survey published by the Foundation for Advancements in Science and Education
also found styrene in human fatty tissue with a frequency of 100% at levels from 8 to
350 nanograms/gram (ng/g). The 350 ng/g level is one third of levels known to cause
neurotoxic symptoms.[5] determined that Styrofoam
drinking
leach Styrofoam into the liquids they contain. The cups apparently lose weight during
the time they are at use. The studies showed that tea with lemon produced the most
marked change in the weight of the foam cup.[1]
1. “Are Styrene Food and Beverage Containers A Health Hazard?,”
Institute for Local Self-Reliance, Washington, DC, August 15, 1990.
2. Brian Lipsett, “Areas of Expertise Pertaining to McDonald’s Corp..”
3. K. Figge, “Migration of Additives from Plastic Films into Edible Oils
and Fat Stimulants,” Food Cosmet Toxicol, December 10, 1972, Vol. 6, pages
815
828.
4. B.J. Dowty, J.L. Laseter, and J. Storet, “Ther Transplacental Migration
and Accumulation in Blood of Volatile Organic Constituents,” Pediatric
Research,
Vol. 10, pages 696-701, 1976.
5. “Polystyrene Fact Sheet,” Foundation for Advancements in Science and
Education, Los Angeles, California.
Health Effects
The fact that styrene can adversely affect humans in a number of ways raises serious
public health and
safety questions regarding its build-up in human tissue and the root cause of this build-
up. According
to a Foundation for Achievements in Science and Education fact sheet, long term
exposure to small
quantities of styrene can cause neurotoxic (fatigue,
nervousness, difficulty
sleeping), hematological (low platelet and hemoglobin values), cytogenetic
(chromosomal and lymphatic
abnormalities), and carcinogenic effects.[1,2] In 1987,
the International
Agency for Research on Cancer, Lyon, France, reclassified styrene from a Groups 3 (not
classifiable as to
its carcinogenicity) to a Group 2B substance (possibly carcinogenic to humans).
Although there is evidence that styrene causes cancer in animals, it has not yet been
proven to cause cancer in humans. Styrene primarily exhibits its toxicity to humans as
a neurotoxin by attacking the central and peripheral nervous systems. The accumulation
of
these highly lipid-soluble (fat-soluble) materials in the lipid-rich tissues of the brain,
spinal cord, and peripheral nerves is correlated with acute or chronic functional
impairment of
the nervous system. [3]
For example, women exposed to low concentrations of styrene vapors in the workplace
are known to have a variety of neurotoxic and menstrual problems. A Russian study of
110 women exposed to styrene vapors at levels about 5 mg/m3 demonstrated menstrual
disorders, particularly perturbations of the menstrual cycle and a hypermenorrhea
(unusually heavy flow of menses during the menstrual cycle) syndrome. Styrene-
exposed women often suffered from metabolic disturbances occurring during pregnancy.
[4]
1. “Are Styrene Food and Beverage Containers A Health Hazard?,”
Institute for Local Self-Reliance, Washington, DC, August 15, 1990.
2. B.J. Dowty, J.L. Laseter, and J. Storet, “The Transplacental
Migration
and Accumulation in Blood of Volatile Organic Constituents,” Pediatric
Research, Vol. 10, pages 696-701, 1976.
3. J.L. O’Donoghue, Neurotoxicity of Industrial and Commercial
Chemicals: Vol. 2, CRC Press, Inc., Boca Raton, Florida, 1985, pages 127-137.
4. N.S. Zlobina, A.S. Izjumova, and N.Ju. Ragul’e, “Effects of Low
Styrene Concentrations On The Specific Functions of the Female Organism” (human and
white rat), Gigiena truda i professional’nye sabolenavija, Moskva, USSR,
December 1975, No. 12, pages 21-25.
Styrene Where?
There are several reasons why styrene-based cups could be a source of contamination.
First, the styrene monomer (vinyl benzene), a colorless or yellowish oily liquid, is
the feedstock in the manufacture of polystyrene. Since the manufacturing process is
not 100% efficient, polystyrene contains some residual styrene.
Second, styrene is soluble in oil and ethanol [1,2,3,4] —
substances commonly found is foods and
alcoholic beverages. For instance, red wine will instantly dissolve the monomer. A 1985
Cuban study noted migration of monomers from low and high density polyethylene into
milk, yogurt, and alcohol solutions.[5] This means that
ingestion can take place by using polystyrene cups to drink beer, wine, mixed drinks or
perhaps even coffee with cream.
Most interesting is the degradation of food that contains vitamin A (betacarotene).
In packaged foods with the addition of heat (such as microwave temperatures),
vitamin A will decompose and produce m-xylene, toluene, and 2,6-dimethylnaphthalene.
Toluene will aggressively dissolve polystyrene. This renders polystyrene as an unsuitable
package for containing or microwaving products that contain vitamin A.[6]
1. Kirk-Othmer, “Physical Properties of Styrene Monomer,”
Encyclopedia of Chemical Technology, Vol. 21, page 771.
2. Joseph Miltz, “Migration of Low Molecular Weight Species From
Packaging Materials: Theoretical and Practical Consideration,” Michigan State
University,
East Lansing, Michigan, July 1986.
3. Kirk-Othmer, “Latex Technology,” “Water Solubilities of Some
Commercially
Important Monomers,” Encyclopedia of Chemical Technology, Vol.
14, page 83.
4. M. Garcia Melian, E. Bernal Torres, and Valera Diaz, “Total Migration
From Plastic Yoghurt Pots,” Revista Cubana de Hygiene y Epidemiologia, Sancti
Spiritus, Cuba, Vol. 23, No. 4, pages 441-446, 1985.
5. D. Macias Matos, Z. Vidland Candebat, Y. Prieto Gonzales, and M.
Fontaine Semanat, “Sanitary Evaluation of Containers or Milk Products.”
6. George Baggett, “Styrene Migration Into Human Adipose Tissue,”
August,
7, 1990.
Infants?
Further, since alcohol crosses
the placental barrier [1] this could be the vehicle of
transmission of styrene monomer into the fetus, and could
explain why small children have traces of styrene monomer in their tissues even though
they have never been exposed to the monomer directly. In a study of 12 breast milk samples from New
Jersey, Pennsylvania, Louisiana, 75% were contaminated with styrene amongst other
hazardous chemicals.
1. Dora B. Gold stein, M.D., “Absorption, Distribution and Elimination of
Ethanol,” Pharmacologies of Alcohol, Oxford Press, 1983.
In My Cereal? Styrene as a Food Additive
“If you do not want to sprinkle styrene monomer on your breakfast cereal each
morning, it has no business being a food additive.” [1]
Even if styrene were declared non-carcinogenic, is it “safe”
as a food additive? Serious questions exist as to the carcinogenic and mutagenic impact
of metabolites of styrene monomer (styrene-7,8-oxide, a
known
carcinogen, and mandelic acid, a known mutagen), while the neurotoxic impact of this
monomer may outstrip the carcinogenic and mutagenic implications. Further, 100
percent
of the public has levels of styrene monomer at concentrations between 8-350 ng/g.[2] An obvious source of the monomer is food and beverage
containers. Finally, neurotoxic problems occur at levels within one order of magnitude
of
known exposure concentrations currently found in adipose tissue. [3]
According to the Federal Food, Drug, and Cosmetic Act:
Section 210 S. The term “food additive” means any substance the intended use
of
which results of may reasonably be expected to result, directly, or indirectly, in its
becoming a component or otherwise affecting the characteristic of any food (including
any
substance intended for use in producing, manufacturing, packing, transporting, or holding
foods; and including any sources of radiation intended for such use), if such substance is
not generally recognized, among experts qualified by scientific training and experience to
evaluate its safety, as having adequately shown through scientific procedures (or, in the
case of a substance used in food prior to January 1, 1958, through either scientific
procedures or experience based on common use in food) to be safe under the conditions
of its
intended use; except that such term does not include
(1) a pesticide chemical in or
on a
raw
agricultural commodity;
(2) or a pesticide chemical to the extent that it is intended
for
use or is used in the production, storage or transportation of any raw agricultural
commodity;
or
(3) a color additive;
(4) any substance used in accordance with a sanction or
approval granted prior to the enactment of this paragraph. Pursuant to this act, the
Poultry
Products Inspection Act (21USC451 and the following) or the Meat Inspection Act of
Mar. 4, 1907 (34STAT.1260) as amended and extended (21USC71 and the following);
or
(5) a new animal drug. [4]
The term “food additive” plainly includes not only substances that are intentionally
added to foods, such as direct food additives…, but also substances that are not
intentionally added but nevertheless contact and are reasonably expected to migrate to
food.[5] Therefore, styrene monomer that migrates into
food
from packaging is by definition a food additive. It has been shown that styrene monomer
can affect the quality of food products at known migration levels, and over 50 percent of
the migration of residual monomer occurs within twenty-four hours (within the normal
shelf life of many food products.[6]
1. George Baggett, “Styrene Migration Into Human Adipose Tissue,”
August 7, 1990.
2. “Polystyrene Fact Sheet,” Foundation for Advancements in Science and
Education, Los Angeles, California.
3. George Baggett, “Styrene Migration Into Human Adipose Tissue,”
August 7, 1990.
4. Federal Food, Drug and Cosmetic Act, as amended January 1980.
5. T. Meretoja, H. Vainio, M. Sorsa, and H. Harkonen, Mutation
Research, Vol. 56, No. 2, pages 193-197, 1997.
6. Joseph Miltz, “Migration of Low Molecular Weight Species From
Packaging Materials: Theoretical and Practical Consideration,” Michigan State
University,
East Lansing, Michigan, July 1986.
Additional Information About Styrene Monomer
Other than its use in polystyrene production, styrene
monomer
is used to form ABS plastic, resins, polyesters, and insulators.
The metabolites of styrene are mandelic acid, a known mutagen, and styrene oxide, a known carcinogen.
See SIRC Review, Styrene Information and Research Center, Washington, DC,
April 1990, for more information. (Be forewarned, this is an industry publication.)
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Last modified: 4 Mar 1996
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