Appendix C - Passaic River Public Digital Library

Table 5-3. Crab Consumption Patterns for Consumers Surveyed in the
Newark Bay Complex in 1999. a
Parameter
Consumers of
Crab Only
Consumers of
Both Crab and
Fish
Sample size (n) 110 33
Number of times per month self-caught crabs are
consumed
3.39 ± 0.42 2.96 ± 0.45
Number of self-caught crabs (i.e., serving size) 6.15 ± 0.85 7.27 ± 0.91
Amount of self-caught crabs for each serving (g) 439 ± 61.2 509 ± 63.8
Monthly consumption of self-caught crabs (g) 1,980 ± 561 1,620 ± 330
Number of months per year crabs are caught 3.31 ± 0.13 3.50 ± 0.37
Yearly consumption of self-caught crab (g) b 5,760 ± 1,360 6,230 ± 1,790
Source: Burger, 2002 (Table 2).
a. Values provided are means ± standard errors based on computed yearly consumption for each person individually;
therefore, yearly consumption values provided in the table are not exactly reproducible.
b. Assumes average weight of meat from crabs is 70 g.
For purposes of this risk assessment, consumption of crab and fish were assumed to occur in separate
populations so that people ate either fish or crab, but not both. This approach may potentially
underestimate risks for those individuals who consume both fish and crabs. As shown in Table 5-3,
individuals who caught both fish and crab reported eating more crab per year than those who caught only
crab. The uncertainty associated with assuming individuals did not eat both fish and crab is further
addressed in Section 5.4, “Uncertainty Analysis”.
Based on the crab consumption patterns for people who caught crab only, as reported in Burger (2002),
the RME ingestion rate for the adult angler/sportsman was calculated as 23 g/day. This value is the 95%
UCL of the yearly consumption value, derived as follows:
g ⎛
g ⎞
5,
760 + ⎜1.
96×
1,
360 ⎟
year
year
95%
UCL =
⎝
⎠
(5-2)
days
365
year
Although Burger (2002) did not identify the distribution of the data, the data were assumed to be
normally distributed based on the central limit theorem. This states that sampling distribution means tend
toward normality as n gets large. In this particular case, n=110, which justifies the use of procedures
based on the normal distribution even if the underlying population is not normal (McBean and Rovers,
1998).
The average yearly consumption rate of 5,760 g/year (16 g/day) was selected as the adult CTE ingestion
rate. Ingestion rates for the child and adolescent receptors were estimated assuming rates 1/3 and
2/3 those of the adult ingestion rate, respectively, as was assumed for fish ingestion.
Draft Focused Feasibility Study Risk Assessment 5-14 June 2007
Lower Passaic River Restoration Project Appendix C