Environmental Engineering Reference
In-Depth Information
table 14.1
Percentage of Lake Acres and
River Miles Under Advisory for One or More
Contaminants by State in 2006
developmental delays even though their mothers showed
little or no signs of toxicity, as noted in a USEPA report
(1997). The difference in susceptibility between adults and
developing fetuses may be a result of mercury's direct dis-
ruption of developmental processes. In addition, children
may experience continued susceptibility due to the lack of
a complete blood-brain barrier, decreased mercury excre-
tion, or increased absorption of mercury from milk during
the developmental stage (USEPA, 1997).
Other populations are vulnerable because of poten-
tially high mercury exposures resulting from consump-
tion behaviors. While PCBs and other contaminants that
accumulate in the fat of fi sh can largely be removed by
trimming or cooking, mercury accumulates in muscle tis-
sues, from which it cannot be removed. When people eat
contaminated fi sh, therefore, they are exposed to mer-
cury. However, the extent of exposure is infl uenced by
the source, size, and species of fi sh consumed, as well as
by the frequency and size of fi sh meals eaten. A report by
the ATSDR (1999) notes that sport fi shers and subsistence
fi shers—including some Native American tribes (Dellinger,
2004)—who consume fi sh from local, contaminated
waters can experience greater exposure to mercury than
people who eat commercial fi sh from a variety of sources.
Similarly, people who eat fi sh that likely have relatively
high accumulations of mercury in their tissues—like larger
(and therefore presumably older) fi sh, and piscivorous (fi sh-
eating) fi sh species—have a higher risk of exposure. Finally,
individuals who routinely consume large amounts of fi sh
are more likely to be exposed to mercury than those who
eat little or no fi sh (ATSDR, 1999).
Although vulnerable populations may be at a higher risk
of adverse health effects from mercury than the general
population, some of these populations also obtain greater
benefi ts from consuming fi sh than does the general pop-
ulation. As a result, restricting or removing fi sh from the
diets of these vulnerable populations can introduce risks
that might not occur when fi sh consumption is restricted
or avoided in the general population. For this reason, when
developing fi sh-consumption advisories targeted toward
vulnerable populations, special care must be taken to
understand the unique benefi ts obtained by the popula-
tion from fi sh—and the unique risks that can result from
removing those benefi ts. The remainder of this section
illustrates some of the unique risk-benefi t issues of vulner-
able populations.
% Lake acres
under advisory a
% River miles
under advisory a
State
Alabama
0.1
0.7
Arizona
1.2
0.1
Arkansas
0.7
0.3
California
19.7
0.1
Colorado
16.5
0.0
Delaware
8.9
24.3
Georgia
11.2
4.2
Hawaii
0.0
16.2
Idaho
29.8
0.0
Iowa
0.2
0.2
Kansas
0.0
0.1
Louisiana
3.5
1.2
Michigan
100.0
3.5
Minnesota
100.0
3.5
Mississippi
7.2
0.3
Nebraska
3.9
0.9
Nevada
0.0
0.4
New Mexico
19.5
0.1
North Carolina
0.1
0.2
Oregon
2.6
0.5
South Carolina
16.7
5.2
South Dakota
1.4
0.0
Tennessee
9.2
0.6
Texas
12.5
0.1
Utah
0.0
0.1
Virginia
9.3
4.7
United States
38.0
26.0
source: Adapted from USEPA (2007).
note: Alaska and Wyoming had no advisories in 2006. The
remaining 22 states and the District of Columbia had 100% of their
lake acres and river miles under advisory in 2006.
a Does not include the Great Lakes or their connecting waters; 100%
of the Great Lakes and their connecting waters were under advisory
in 2006.
Unusually Susceptible or Sensitive Populations
NUTRITIONAL RISKS OF LIMITING FISH IN DIETS
at a particular level of mercury exposure than the general
population does. Included in this category are develop-
ing fetuses (and, therefore, women who are pregnant or
of reproductive age) and young children. In Minamata,
infants exposed to mercury in utero experienced marked
Given fi sh's high nutritional content, the restriction or
removal of fi sh from the diet can itself introduce health risks.
One of the populations for which this can be a special con-
cern is developing fetuses. A study by Hibbeln et al., (2007),
for example, found that, despite mercury's potential ability
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