WSP11434

• File Number: 8200.750
• Description: San Juan River General
• State: CO
• Basin: San Juan/Dolores
• Water Division: 7
• Date: 4/1/1994
• Author: USFWS
• Title: Polycyclic Aromatic Hydrocarbon Investigation for the San Juan River - San Juan County - New Mexico 1993 - April 1994
• Water Supply Pro - Doc Type: Report/Study

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in rainbow trout exposed via diet. BaP can be readily accumulated in the ovary, wolffian
ducts, oocytes, gonads and semen of fish and consequently transferred to developing
gametes (Hose et al. 1981; Reichert and Varanasi 1982). BaP has also been shown to
bind to both liver and gonadal proteins and DNA (Varanasi et al. 1982).

The role of sediments in retention of PAHs in the environment are of some importance to
bottom dwelling fish such as the flannelmouth suckers. Johnston and Baumann (1989)
reported BaP concentrations in brown bullhead which generally reflected sediment
concentrations in the area where fish were collected. Baumann et al. (1982) reported the
same PAH metabolites in fish that were in sediments from that site. The amount of
harmful PAH metabolites and their distribution in the environment will depend on the
chemical properties of specific compounds. However, the presence of numerous facilities
for the utilization or processing of petroleum hydrocarbon compounds (i.e coal-fired power
production, petroleum refining, automobiles, etc.) can contribute heavily to local or
widespread contamination of a riverine environment (Al-Saad and Al-Timari 1989;
Johnston and Baumann 1989; Krahn et al. 1986b).

Eisler (1987) states that many PAHs such as naphthalene and phenanthrene are acutely
toxic at whole body concentrations above 50,000 ppm and deleterious sublethal responses
occur at concentrations in the range of 100 to 5000 ppm. The six-ring aromatic
hydrocarbon, BaP, is among the more toxic PAH compounds, causing deleterious effects at
whole body concentrations above 100 ppm. Eleven of the twenty-four flannelmouth
sucker samples collected for this study had biliary concentrations of BaP in excess of
Eisler's recommended lower limit for deleterious effects to aquatic life. Naphthalene and
phenanthrene are also found in the aquatic environment, although these PAHs are not
known carcinogens or mutagens. The levels of naphthalene, phenanthrene, and BaP in
flannelmouth suckers collected for this study are much lower than levels reported in fish
from a similar study of lake Powell in Utah (the eventual destination of San Juan River
drainage) which were clearly hazardous from a carcinogenic risk level (Waddell and Weins,
1993). The concentrations of BaP metabolites that Waddell and Weins observed in the
San Juan arm of lake Powell ranged from 110 to 1,500 ng/g wet weight; naphthalene
metabolites ranged from 16,000 to 810,000 ng/g and phenanthrene metabolites ranged
from 3,900 to 330,000 ng/g. Bruce Waddell, Environmental Contaminant Specialist with
the Service's Ecological Services State Office in Salt lake City, indicated that, according
to Texas A&M, the higher of these ranges are clearly hazardous to fish species from a
carcinogenic risk level (Waddell, pers. comm., 1994).

Although the elevated PAH levels in flannelmouth suckers cannot be translated into
quantifiable health-related risks to fish and other biota within the San Juan River
ecosystem, the presence of these potentially toxic substances provides a legitimate basis
for initial concern and a more detailed assessment of PAH-related risks to important
elements of the San Juan River aquatic ecosystem.

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