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HEALTH CONSULTATION
A Determination of Inorganic Arsenic Concentrations in Fish from the North Fork of the American Fork Canyon


AMERICAN FORK CANYON/UINTA NATIONAL FOREST
PLEASANT GROVE, UTAH COUNTY, UTAH

BACKGROUND AND STATEMENT OF ISSUES

The North Fork of the American Fork Canyon is located in the Wasatch Mountains, approximately 40 miles southeast of Salt Lake City, Utah (Figure 1). The American Fork Canyon is easily accessible to the 1.4 million people estimated to live along the Wasatch front range. During the spring and summer months, an average of 2,600 vehicles per day visit the American Fork Canyon - Alpine Loop Recreation Area. Fishing is a common recreational activity in these areas.

Hatchery-reared rainbow trout are stocked yearly in the American Fork River, the Tibble Fork Reservoir, and the Silver Lake Flat Reservoir. In addition to these stocked fish, cutthroat, and brown trout are native to the American Fork River.

A 1999 analysis of metals in fish from the North Fork of the American Fork Canyon revealed a higher than average concentration of total arsenic. Therefore, a fish consumption advisory was issued in June of 2002.

As a continuation of a monitoring program to assess the potential impacts from abandoned mining operations in American Fork Canyon, personnel from the Utah Division of Wildlife Resources collected three species of fish (cutthroat, brown, and rainbow trout) for tissue sampling from the North Fork of the American Fork Canyon in August of 2002. These fish were analyzed for total arsenic, as well as inorganic arsenic. After reviewing this current data, the Environmental Epidemiology Program (EEP) of the Utah Department of Health is recommending that the fish consumption advisory for the North Fork of the American Fork Canyon issued in 2002 be removed.

METHODS

Fifteen whole trout from the North Fork of the American Fork Canyon and five control fish from the Utah State Fish Hatchery in Springville, Utah were collected and delivered to Trace Element Research Laboratory at Texas A&M University for analysis of total and inorganic arsenic. The fish were filleted, with skin on, and analyzed for moisture content and total and inorganic arsenic concentrations. Inorganic arsenic was determined using hydride generation-atomic fluorescence spectroscopy following extraction with hydrochloric acid. Total arsenic was determined by inductively coupled plasma-mass spectroscopy following wet digestion with nitric acid and hydrogen peroxide. Moisture content was reported as a percent of wet sample weight and arsenic concentrations were reported in units of parts per million(1) on a wet weight basis (Table 1).

RESULTS

Arsenic Concentrations

Total and inorganic arsenic concentrations were determined for two trout species native to the American Fork River, brown and cutthroat, and also for the transplanted rainbow trout species. Concentrations of total arsenic in brown trout ranged from 0.0978 - 0.612 milligram arsenic per kilogram fresh fish weight (mg/kg), with the percent inorganic arsenic ranging from 0.9 - 6.9 percent. The cutthroat trout displayed a narrower range of total arsenic, 0.0618 - 0.137 mg/kg, but a much greater range of percent inorganic arsenic, 1.9 - 12.5 percent. Total arsenic in rainbow trout ranged from 0.0647 - 0.244 mg/kg. Percent inorganic arsenic in rainbow trout ranged from less than 0.6 - 7.4 percent. Fish collected from the Utah State Fish Hatchery in Springville served as the control. The hatchery fish displayed higher amounts of total arsenic content, ranging from 0.413 - 0.748 mg/kg, but had a much lower percent of inorganic arsenic, ranging from 0.3 - 0.7 percent. The complete results are presented in Table 1.

Charts illustrating the mean arsenic concentrations and percentages for the trout analyzed are presented in Figures 3, 4, and 5. The hatchery trout presented the highest mean total arsenic concentration at 0.5348 ppm. Brown trout had the highest mean inorganic arsenic concentration at 0.00486 ppm. The mean percent inorganic arsenic content was comparable between the species, 3.15 percent for brown trout, 4.58 percent for rainbow, and 4.66 percent for cutthroat. The mean percent inorganic arsenic detected in the hatchery trout was 0.52 percent.

Total arsenic versus percent inorganic arsenic is presented in Figure 6. High levels of total arsenic tend to correspond with low levels of percent inorganic arsenic in both species. The relationships between the inorganic arsenic concentration and fish weight and length in the brown and cutthroat trout are graphed in Figures 7 and 8. Inorganic arsenic concentrations in cutthroat trout appear to gradually increase with weight and length.

DISCUSSION

The 1999 analysis of metals in fish from the North Fork revealed high levels of total arsenic, particularly in fish collected from site #2. Because this location is heavily fished, it was determined that the majority of the fish collected for the 2002 sampling be from this site. Five cutthroat and two rainbow trout were selected. The remaining five brown and three rainbow trout were collected a mile and a half upstream from site #2 (UDWR 2002; Figure 2).

Distinction between the types of arsenic present in the fish is essential when determining consumption limits. The organic form of arsenic is usually less harmful than the inorganic form (TOXNET 2000). Consumption limits are set when the concentration of the target analyte exceeds its corresponding screening values (SVs). SVs were developed by the United States Environmental Protection Agency (USEPA) and are used as standards by which levels of contamination can be compared. In this case, the SVs correspond to the concentration of inorganic arsenic in fish tissue that may be harmful to human health.

The 2002 fish advisory for the North Fork was based on the results of the 1999 total metals analysis. Actual inorganic arsenic concentrations were not determined. Inorganic arsenic was estimated to be 10 percent of the total arsenic. It is now evident that this percentage over estimated the actual level of inorganic arsenic in the fish tissue from this fishery. Although a level of total arsenic may be high in a sample, the amount of inorganic arsenic may be low, resulting in a much lower percentage of inorganic arsenic. Conversely, low levels of total arsenic may reveal a high percent of inorganic arsenic, even though the actual inorganic arsenic concentration is very small. The percentage of inorganic arsenic detected within a sample is variable and is dependent upon on the actual concentrations of total and inorganic arsenic. Table 2 presents a comparison between the 1999 and 2002 data.

Results of the 2002 sampling for inorganic arsenic concentrations in fish from the North Fork were compared to the USEPA's SVs. SVs can be calculated for both carcinogenic and non-carcinogenic health effects. The SVs for carcinogenic health effects from inorganic arsenic are calculated in Appendix A. Assumptions made for these calculations are as follows (details in Appendix A):

  Meal Size Consumption Rate Body Weight
Sport Fisher 0.227 kg 0.0175 kg/day 70 kg
Child 0.085 kg 0.007 kg/day 16 kg
Subsistence Fisher 0.227 kg 0.1424 kg/day 70 kg

The recreational sport fisher SV for carcinogenic health effects was applied in this analysis because the North Fork is used primarily by sport fishers. There is no evidence of subsistence fishing in the area. The carcinogen SV for sport fishers is 0.027 milligrams inorganic arsenic per kilogram fresh fish weight (mg/kg). The carcinogen SV for children is 0.015 mg/kg. The SV for subsistence fishers is 0.0033 mg/kg (subsistence fishers are defined as those whose diet contains a much greater portion of fish than an average sport fisher). The North Fork fish tissue analysis indicated a range of less than 0.6 - 12.5 percent of the total arsenic concentration and a concentration of inorganic arsenic ranging from less than 0.0015 - 0.0077 mg/kg.

Edible Fish Tissue Inorganic As (mg/kg) Screening Values for Inorganic Arsenic
American Fork Fish      
Highest 0.0077 Sport Fishers (Adults) 0.027 mg/kg
Average 0.0041 Child 0.015 mg/kg
Hatchery Fish   Subsistence Fisher 0.0033 mg/kg
Highest 0.0032    
Average 0.0027    

Fish tissue with the highest concentration of inorganic arsenic (0.0077 mg/kg, in fish from the North Fork) proved to be much lower than the SVs for sport fishers and children. The calculated SV for subsistence fishers was exceeded by the inorganic arsenic concentration in fish from the North Fork, but not by fish from the hatchery. The EEP is unaware of any subsistence fishing in the North Fork of the American Fork Canyon, and because it is a fee area, it is unlikely that any subsistence fishers would frequent the area. Therefore, because the highest concentration of inorganic arsenic detected does not exceed the SVs for sport fishers or children, the EEP recommends that the fish consumption advisory issued for fish from the North Fork of the American Fork Canyon be removed.

CHILD'S HEALTH CONSIDERATIONS

The Agency for Toxic Substances and Disease Registry recognizes the unique vulnerabilities of infants and children to environmental contaminants. Children are less developed and may have developmental harm from exposure that would not be experienced by a completely developed adult. The developing body systems of children can sustain permanent damage if toxic exposures occur during critical growth stages.

The concentration of inorganic arsenic detected in fish from the North Fork of the American Fork is well below the SV for children. The highest concentration of inorganic arsenic present in trout sampled was 0.0077 mg/kg. The SV for children is 0.015 mg/kg. Consumption limits do not apply to levels that do not exceed the SV.

CONCLUSIONS

Upon further analysis of inorganic arsenic observed in fish from the North Fork of the American Fork Canyon, it is recommended that the fish consumption advisory issued in June of 2002 be removed. Average total and inorganic arsenic levels are much lower than those estimated in the 2002 advisory. Although the screening value for inorganic arsenic concentration in fish tissue for subsistence fishers has been exceeded, the screening values for sport fishers and children have not. The EEP is unaware of any subsistence fishing in the North Fork and daily use fees in the canyon make this possibility unlikely.

RECOMMENDATIONS

The Environmental Epidemiology Program recommends that the fish consumption advisory for fish caught in the North Fork of the American Fork Canyon issued in 2002 be removed. The EEP also recommends that concentrations of total and inorganic arsenic continue to be monitored, as well as levels of chromium, copper, mercury, selenium, and thallium.

PUBLIC HEALTH ACTION PLAN

The Environmental Epidemiology Program of the Utah Department of Health will continue to work with the Utah Department of Environmental Quality, the Utah County Health Department, the Utah Division of Wildlife Resources, the Utah Department of Natural Resources, and the Agency of Toxic Substances and Disease Registry to notify the public of the findings of this revised health consultation. A press release and fact sheet will be prepared to inform the public of the removal of the fish consumption advisory.

The Environmental Epidemiology Program will continue to work with all applicable agencies to perform additional research on arsenic and other metal concentrations in fish from the North Fork of the American Fork Canyon. The Environmental Epidemiology Program will adjust recommendations as new information becomes available.

AUTHORS

Report Prepared By:

Tamra Jones, Health Hazard Assessor
Environmental Epidemiology Program
Office of Epidemiology
Utah Department of Health

John Contreras, Health Hazard Assessment Manager
Environmental Epidemiology Program
Office of Epidemiology
Utah Department of Health

Designated Reviewer:

R. Wayne Ball, Ph.D., DABT, Toxicologist
Environmental Epidemiology Program Manager
Office of Epidemiology
Utah Department of Health

CERTIFICATION

This Health Consultation, A Determination of Inorganic Arsenic Concentrations in Fish from the North Fork of the American Fork Canyon, American Fork, Utah, was prepared by the Utah Department of Health, Environmental Epidemiology Program under a cooperative agreement with the Agency for Toxic Substances and Disease Registry (ATSDR). It is in accordance with approved methodology and procedures existing at the time the public health consultation was begun.

Tammie McRae, MS
Technical Project Officer, DHAC

The Division of Health Assessment and Consultation, ATSDR, has reviewed this health consultation and concurs with its findings.

Richard Gillig
for Roberta Erlwein
Cooperative Agreement Team Leader, DHAC, ATSDR

REFERENCES

EPA 1997. U.S. Environmental Protection Agency. 1997. Health Effects Assessment Summary Tables - FY 1997 Update. Solid Waste and Emergency Response. Superfund. EPA-540-R-97-036.

EPA 2000a. U.S. Environmental Protection Agency. 2000. Guidance for Assessing Chemical Contaminant Data For Use in Fish Advisories: Volume 1, Fish Sampling and Analysis, Third Edition. Office of Water, Washington, DC. EPA 823-B-00-007.

EPA 2000b. U.S. Environmental Protection Agency. 2000. Guidance for Assessing Chemical Contaminant Data For Use in Fish Advisories: Volume 2, Risk Assessment and Fish Consumption Limits, Third Edition. Office of Water, Washington, DC. EPA 823-B-00-008.

EPA 2000c. U.S. Environmental Protection Agency. 2000. Guidance for Assessing Chemical Contaminant Data For Use in Fish Advisories: Volume 3, Risk Management, Third Edition. Office of Water, Washington, DC. EPA 823-B-00-009.

TOXNET 2000. Toxicology Data Network. http://toxnet.nlm.nih.gov National Library of Medicine Specialized Information Services. Includes HSDB (Hazardous Substances Data Bank), and IRIS (Integrated Risk Information System - data from the United States Environmental Protection Agency).

UDOH 2002. Utah Department of Health. 2002. Health Consultation: Metals in Fish from the North Fork of the American Fork Canyon. EPA Facility ID: UTD988074951.

UDWR 2002. Fax Transmission of Field Data Form. August 19, 2002. To: Betsy Revenaugh and Kori Gunn. From: Doug Sakaguchi, Habitat Manager. Subject: North Fork American Fork Ck - Fish samples ready to pick-up.

FIGURES AND TABLES

Location map for the American Fork Canyon Recreational
Figure 1. Location map for the American Fork Canyon Recreational

Locations of Fish Sampling on the North Fork of the American Fork Canyon, 2002
Figure 2. Locations of Fish Sampling on the North Fork of the American Fork Canyon, 2002.

Mean Total Arsenic Concentrations in fish from the North Fork of the American Fork Canyon (based on 2002 sampling analysis)
Figure 3. Mean Total Arsenic Concentrations in fish from the North Fork of the American Fork Canyon (based on 2002 sampling analysis).

Mean Inorganic Arsenic Concentrations in fish from the North Fork of the American Fork Canyon (based on 2002 sampling analysis)
Figure 4. Mean Inorganic Arsenic Concentrations in fish from the North Fork of the American Fork Canyon (based on 2002 sampling analysis).

Mean Percent Inorganic Arsenic in fish from the North Fork of the American Fork Canyon (based on 2002 sampling analysis)
Figure 5. Mean Percent Inorganic Arsenic in fish from the North Fork of the American Fork Canyon (based on 2002 sampling analysis).

Total Arsenic vs. Percent Inorganic Arsenic in fish from the North Fork of the American Fork Canyon (based on 2002 sampling analysis)
Figure 6. Total Arsenic vs. Percent Inorganic Arsenic in fish from the North Fork of the American Fork Canyon (based on 2002 sampling analysis).

Inorganic Arsenic vs. Fish Weight for Brown and Cutthroat Trout from the North Fork of the American Fork Canyon (based on 2002 sampling analysis)
Figure 7. Inorganic Arsenic vs. Fish Weight for Brown and Cutthroat Trout from the North Fork of the American Fork Canyon (based on 2002 sampling analysis).

Inorganic Arsenic vs. Fish Length for Brown and Cutthroat Trout from the North Fork of the American Fork Canyon (based on 2002 sampling analysis)
Figure 8. Inorganic Arsenic vs. Fish Length for Brown and Cutthroat Trout from the North Fork of the American Fork Canyon (based on 2002 sampling analysis).

Table 1.

2002 Sampling Data for Fish from the North Fork of the American Fork Canyon
Lab # Sample ID Total As ppm* wet weight Inorganic As ppm wet weight % Inorganic As % Moisture
T2068-001 BRN 1 0.153 0.0033 2.2% 78.6
T2068-002 BRN 2 0.210 0.004 1.9% 76.3
T2068-003 BRN 3 0.115 0.0045 3.9% 78
T2068-004 BRN 4 0.612 0.0058 0.9% 79.5
T2068-005 BRN 5 0.0978 0.0067 6.9% 77.4
T2068-006 RBT 1 0.0997 0.0074 7.4% 75.2
T2068-007 RBT 2 0.0673 0.0046 6.8% 75
T2068-008 RBT 3 0.0647 0.0033 5.1% 74.2
T2068-009 RBT 4 0.109 0.0032 2.9% 76.3
T2068-010 RBT 5 0.244 <0.0015 <0.6 78
T2068-011 CUT 1 0.115 0.0022 1.9% 76.8
T2068-012 CUT 2 0.0774 0.004 5.2% 76.4
T2068-013 CUT 3 0.0977 0.0017 1.7% 77.7
T2068-014 CUT 4 0.0618 0.0077 12.5% 76.6
T2068-015 CUT 5 0.137 0.0028 2.0% 77.2
T2068-016 RBT Hatchery 1 0.498 0.0032 0.6% 75.9
T2068-017 RBT Hatchery 2 0.748 0.0027 0.4% 76
T2068-018 RBT Hatchery 3 0.413 0.0026 0.6% 72.5
T2068-019 RBT Hatchery 4 0.485 0.0032 0.7% 75.2
T2068-020 RBT Hatchery 5 0.530 0.0016 0.3% 74.3

*ppm = parts per million; equivalent to milligrams per kilogram (mg/kg).
Evaluated as half the detection limit (Inorganic As = 0.00075 ppm; % Inorganic As = 0.3%)
Data Source: Trace Elemental Research Laboratory, 2002.

Table 2.

Comparison of 2002 and 1999 Sampling Data for Fish from the North Fork of the American Fork Canyon.
Edible Fish Tissue 2002 1999
American Fork Fish Total As (mg/kg) Inorganic As (mg/kg) Total As (mg/kg) Inorganic As1 (mg/kg)
Average 0.151 0.0041 0.272 0.0272
High 0.612 0.0077 0.688 0.0688
Low 0.0618 < 0.0015 0.067 0.0067
Hatchery Fish        
Average 0.5348 0.0027 N/A N/A
High 0.748 0.0032 N/A N/A
Low 0.413 0.0016 N/A N/A

1 Inorganic arsenic was estimated as 10% of total arsenic. This estimate was applied because inorganic arsenic concentrations were not actually evaluated. This estimation was much higher than the actual percent of inorganic arsenic determined in the 2002 analysis.

APPENDICES

APPENDIX A: SCREENING VALUE CALCULATIONS (EPA 2000A)

For Carcinogenic Health Effects

SVc = [(RL/SF) * BW] / CR
SVc = Screening value for a carcinogen (in mg/kg or ppm)
RL = Maximum acceptable risk level (dimensionless)
SF = Oral slope factor (mg/kg/d)-1
BW = Mean body weight of the general population or subpopulation of concern (kg).
CR = Mean daily consumption rate of the species of interest by the general population or by the subpopulation of concern averaged over a 70-yr lifetime (in kg/day)

The arsenic SVc was calculated based on the oral slope factor for inorganic arsenic, the most toxic form of arsenic.

For a sport fisher, the calculation looks like this:

Where:
RL = 1/100,000
SF = 1.5 (mg/kg/d)-1
BW = 70 kg
CR = 0.0175 kg/day

therefore,

SVc = 0.027 mg/kg

For a subsistence fisher:

Where:
RL = 1/100,000
SF = 1.5 (mg/kg/d)-1
BW = 70 kg
CR = 0.1424 kg/day

therefore,

SVc = 0.0033 mg/kg

For a child:

Where:
RL = 1/100,000
SF = 1.5 (mg/kg/d)-1
BW = 16 kg
CR = 0.007 kg/day

therefore,

SVc = 0.015 mg/kg

APPENDIX B:

FOR MORE INFORMATION
For more information on health issues - John Contreras
Utah Department of Health
801-538-6191

Tamra Jones
Utah Department of Health
801-538-6191

Dave Johnson
Utah County Health Department
801-370-4525

Jay Pitkin or Dave Wham
Utah Department of Environmental Quality
Salt Lake City, Utah
(801) 538-6052

For more information on mining wastes and National Forest System Lands - Jeremy Jarnecke - Hydrologist
The Uinta National Forest
(801) 342-5110

Robert Easton
Uinta National Forest
Pleasant Grove Ranger District
801-785-3563

For more information of fishery issues - Doug Sakaguchi or Don Wiley
Utah Division of Wildlife Resources
Central Region
801-491-5678

1 Parts per million (ppm) can also be reported as milligrams per kilogram (mg/kg). 1 ppm is equal to 1 milligram of arsenic per kilogram fresh fish weight (mg/kg).


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