3.3 Alkylphenols and Alkylphenol Ethoxylates
Nonylphenol (NP) and octylphenol are the largest volume alkylphenol products
manufactured in the USA. Alkylphenols (APs) such as nonylphenol and octylphenol
are mainly used to make alkylphenol ethoxylate (APE) surfactants. These surfactants
are the primary active ingredients in industrial chemicals that are used as cleaning
and sanitizing agents. Nonylphenol ethoxylates (NPEs) account for approximately
80% of total APE use with total US production exceeding 500 million pounds per
year [9]. Alkylphenols are also used as plasticizers, in the preparation of phenolic
resins, polymers, heat stabilizers, antioxidants, and curing agents. APEs do not break
down completely in wastewater treatment plants or in the environment. The most
widely used NPEs have nine- or ten-member carbon chains attached to the
ethoxylate group. Thus, the great majority of NPEs in use are easily dissolved in
water. Human exposure to APs and APEs may occur through contaminated drinking
water that has been extracted from polluted waters. At present there is no conclusive
evidence that APs or APEs cause adverse health effects in humans; however, there
are many reports of alkylphenols causing production of a female-associated liver
protein, vitellogenin, in male fish [27].
Investigations of NP levels in rivers have found values varying between 2μg/L in
the Delaware River in Philadelphia to 1000μg/L in the Rhine and 1000μg/L in a
tributary of the Savannah River [9, 28]. Drinking water is frequently taken from
rivers and can easily become contaminated with alkylphenols. Analysis of many
drinking water samples in the USA has found an overall average concentration of
alkylphenolic compounds of 1μg/L. Studies in the USA show NPE removal from
wastewater ranging from 92 to 99% with minor seasonal variations. NPE concentrations in discharges after treatment are reportedly low, varying between 50 and
200μg/L. Draft USEPA water quality guidelines for nonylphenol in freshwater are
6.6μg/L water (four-day average) and 25μg/L (one-hour average), and in saltwater,
they are 1.6μg/L (four-day average) and 6.2μg/L (one-day average).
3.4 Plastic Additives
3.4.1 Bisphenol A
Bisphenol A is an industrial chemical used to synthesize epoxy resins or polycarbonate plastic. Human exposure to the potential endocrine disrupting effects of
bisphenol A may occur when this chemical leaches out of the plastic due to
incomplete polymerization or breakdown of the polymer upon heating.
Polycarbonates are commonly used for food and drink packaging materials, and
infants are the subgroup of the population that is most highly exposed to this
compound. Bisphenol A is also used in plastic dental fillings.
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Nonylphenol (NP) and octylphenol are the largest volume alkylphenol products
manufactured in the USA. Alkylphenols (APs) such as nonylphenol and octylphenol
are mainly used to make alkylphenol ethoxylate (APE) surfactants. These surfactants
are the primary active ingredients in industrial chemicals that are used as cleaning
and sanitizing agents. Nonylphenol ethoxylates (NPEs) account for approximately
80% of total APE use with total US production exceeding 500 million pounds per
year [9]. Alkylphenols are also used as plasticizers, in the preparation of phenolic
resins, polymers, heat stabilizers, antioxidants, and curing agents. APEs do not break
down completely in wastewater treatment plants or in the environment. The most
widely used NPEs have nine- or ten-member carbon chains attached to the
ethoxylate group. Thus, the great majority of NPEs in use are easily dissolved in
water. Human exposure to APs and APEs may occur through contaminated drinking
water that has been extracted from polluted waters. At present there is no conclusive
evidence that APs or APEs cause adverse health effects in humans; however, there
are many reports of alkylphenols causing production of a female-associated liver
protein, vitellogenin, in male fish [27].
Investigations of NP levels in rivers have found values varying between 2μg/L in
the Delaware River in Philadelphia to 1000μg/L in the Rhine and 1000μg/L in a
tributary of the Savannah River [9, 28]. Drinking water is frequently taken from
rivers and can easily become contaminated with alkylphenols. Analysis of many
drinking water samples in the USA has found an overall average concentration of
alkylphenolic compounds of 1μg/L. Studies in the USA show NPE removal from
wastewater ranging from 92 to 99% with minor seasonal variations. NPE concentrations in discharges after treatment are reportedly low, varying between 50 and
200μg/L. Draft USEPA water quality guidelines for nonylphenol in freshwater are
6.6μg/L water (four-day average) and 25μg/L (one-hour average), and in saltwater,
they are 1.6μg/L (four-day average) and 6.2μg/L (one-day average).
3.4 Plastic Additives
3.4.1 Bisphenol A
Bisphenol A is an industrial chemical used to synthesize epoxy resins or polycarbonate plastic. Human exposure to the potential endocrine disrupting effects of
bisphenol A may occur when this chemical leaches out of the plastic due to
incomplete polymerization or breakdown of the polymer upon heating.
Polycarbonates are commonly used for food and drink packaging materials, and
infants are the subgroup of the population that is most highly exposed to this
compound. Bisphenol A is also used in plastic dental fillings.
182
N. K. Shammas et al.