Environmental Engineering Reference
In-Depth Information
7.8.14 Emerging Contaminants
Through research, we are now learning about the presence in the environment of many
chemicals and microbes that historically were not considered contaminants (USGS
2009c). Emerging contaminants originate from urban and agricultural sources and
impact soil and groundwater at many urban locations. The potential health risks posed
by emerging contaminants are not fully known. Many emerging contaminants enter the
environment from residential waste products, and this fact has prompted a shift in tra-
ditional thinking that held most releases of contaminants were from industrial sources
(Barnes et al. 2008).
Emerging contaminants include a wide variety of compounds consisting of the follow-
ing (Barnes et al. 2008; USGS 2009c):
• Pharmaceuticals and drugs including
• Antibiotics
• Steroids
• Antibacterial chemicals
• Hormones
• Narcotics
• Many other legal and illegal drugs
• Insect repellants
• Solvents
• Detergents
• Plasticizers
• Fire retardants
• Veterinary antibiotics
• Others
Common pharmaceuticals and drugs with the capability of
becoming contaminants if not properly disposed include the
following:
OH
H
• Hormones, such as testosterone
• Antibiotics, such as penicillin
• Sildenafil citrate, commonly known as Viagra
• Benzoylmethylecgonine, commonly known as cocaine
H
H
O
FIGURE 7.34
Structure of testosterone.
Benzoylmethylecgonine or cocaine is a stimulant affecting the
central nervous system, and also acts as an appetite suppressant.
Antibiotics inhibit the growth of bacteria. Sildenafil citrate is an
arterial stimulant (Barnes et al. 2008). Testosterone is a male sex
hormone, an anabolic steroid, and affects the growth of muscle
mass. Figures 7.34 through 7.37 show the structures of testoster-
one, penicillin, sildenafil nitrate, and benzoylmehylecgonine,
respectively.
H
H
N
R
S
CH 3
O
N
CH 3
O
COOH
FIGURE 7.35
Structure of the antibiotic
penicillin.
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