polish, hair spray, soap and shampoo. Phthalates can be subdivided as high and low
molecular weight phthalates, depending on their molecular weight. High molecular
weight phthalates include those with 7 or more carbon atoms in their chemical
backbone, giving them increased permanency and durability. The most common
high molecular weight phthalates are di(2-ethylhexyl) phthalate and dioctyl phthalate. Low molecular weight phthalates include those with less than 7 carbon atoms in
their chemical backbone. The most common low molecular weight phthalates
include dimethyl phthalate and diethyl phthalate.
15.1.1 The Toxicity and the Physicochemical Properties
of Phthalates
Without stable chemical bonds to polymer, the phthalates in flexible plastics can be
released easily and migrate into the environment. Through drinking water, digestion
of food and inhalation of air, the phthalates in the environment can easily enter into
the human body and then bioaccumulate in fat tissues, because they are lipophilic
chemicals.
Many epidemiological and laboratory evidences have shown that phthalates are
toxic, especially to the reproductive and endocrine systems, which can lead to fetal
malformations and abnormal growth, as well as the maldevelopment of children
(Li et al. 2019; Rashad et al. 2018; Gao et al. 2017; Keresztes et al. 2013).
Herreros et al. (2013) found that di(2-ethylhexyl) phthalate interfered with
the estrogen level. The blood estrogen level of the sheep exposed to di(2-ethylhexyl)
phthalate was significantly higher than that of the control group, and the blood
progesterone concentration was also significantly increased from the second day of
the luteal cycle. Swan et al. (2005) found that fetal phthalate exposure could reduce
the anogenital distance in male infants and affect their development of the reproductive system. These findings supported the hypothesis that exposure to phthalates
at fetal environmental levels could adversely affect male reproductive development.
Studies by Parks et al. (2000) have indicated that di(2-ethylhexyl) phthalate has an
antiandrogen effect, and it could reduce the testosterone level of male fetal mice in
the critical period of reproductive system differentiation to the female level.
Ferguson et al. (2014) found that spontaneous abortion was strongly correlated
with the concentration of phthalate metabolites in the urine of pregnant women in
the third trimester of pregnancy. In addition, the carcinogenicity of phthalates was
studied by the National Toxicology Agency (National Toxicology Program, NTP) in
1982 (Chen and Ni 2010). The results showed that long-term absorption of
phthalates for rats and mice could lead to their liver cancer. The mutagenicity and
neurotoxicity of phthalates and their association with obesity in adults (Stahlhut et al.
2007), asthma, and allergic symptoms in children (Bornehag et al. 2004) have also
been reported. Yang et al. (2008) confirmed the adjuvant effect of di(2-ethylhexyl)
phthalate in mice immunized with ovalbumin. The dose of di(2-ethylhexyl)
15 Analytical Methods for Phthalates in Water Samples
541
molecular weight phthalates, depending on their molecular weight. High molecular
weight phthalates include those with 7 or more carbon atoms in their chemical
backbone, giving them increased permanency and durability. The most common
high molecular weight phthalates are di(2-ethylhexyl) phthalate and dioctyl phthalate. Low molecular weight phthalates include those with less than 7 carbon atoms in
their chemical backbone. The most common low molecular weight phthalates
include dimethyl phthalate and diethyl phthalate.
15.1.1 The Toxicity and the Physicochemical Properties
of Phthalates
Without stable chemical bonds to polymer, the phthalates in flexible plastics can be
released easily and migrate into the environment. Through drinking water, digestion
of food and inhalation of air, the phthalates in the environment can easily enter into
the human body and then bioaccumulate in fat tissues, because they are lipophilic
chemicals.
Many epidemiological and laboratory evidences have shown that phthalates are
toxic, especially to the reproductive and endocrine systems, which can lead to fetal
malformations and abnormal growth, as well as the maldevelopment of children
(Li et al. 2019; Rashad et al. 2018; Gao et al. 2017; Keresztes et al. 2013).
Herreros et al. (2013) found that di(2-ethylhexyl) phthalate interfered with
the estrogen level. The blood estrogen level of the sheep exposed to di(2-ethylhexyl)
phthalate was significantly higher than that of the control group, and the blood
progesterone concentration was also significantly increased from the second day of
the luteal cycle. Swan et al. (2005) found that fetal phthalate exposure could reduce
the anogenital distance in male infants and affect their development of the reproductive system. These findings supported the hypothesis that exposure to phthalates
at fetal environmental levels could adversely affect male reproductive development.
Studies by Parks et al. (2000) have indicated that di(2-ethylhexyl) phthalate has an
antiandrogen effect, and it could reduce the testosterone level of male fetal mice in
the critical period of reproductive system differentiation to the female level.
Ferguson et al. (2014) found that spontaneous abortion was strongly correlated
with the concentration of phthalate metabolites in the urine of pregnant women in
the third trimester of pregnancy. In addition, the carcinogenicity of phthalates was
studied by the National Toxicology Agency (National Toxicology Program, NTP) in
1982 (Chen and Ni 2010). The results showed that long-term absorption of
phthalates for rats and mice could lead to their liver cancer. The mutagenicity and
neurotoxicity of phthalates and their association with obesity in adults (Stahlhut et al.
2007), asthma, and allergic symptoms in children (Bornehag et al. 2004) have also
been reported. Yang et al. (2008) confirmed the adjuvant effect of di(2-ethylhexyl)
phthalate in mice immunized with ovalbumin. The dose of di(2-ethylhexyl)
15 Analytical Methods for Phthalates in Water Samples
541