Fish Consumption Risk Analysis for , July 2011

BACKGROUND INFORMATION boundary at Gisela, the creek flows into the valley Tonto Creek is a perennial stream located in Gila between the Mazatzal and mountains County, in central Arizona. From its origin at Tonto ending at an altitude of 2,119 feet where it flows Springs, just below the , Tonto Creek into Roosevelt Lake. flows through dense Ponderosa pine forest, deep Geology canyons and desert chaparral to its confluence with Tonto Creek Spring issues from a limestone the at Roosevelt Lake (Figure 1). Along its aquifer in an area of Permian to Pennsylvanian sed- course, it receives the flows of several smaller imentary material and then flows through streams including Horton, Spring, Christopher and Mississippian, Devonian, and Cambrian sedimenta- Haigler Creeks and runs past summer cabins in the ry rocks. As it flows through the canyon of the Kohl’s Ranch area and Bear Flats and through the it meets Early Proterozoic rural areas known as Gisela, Punkin Center and quartzite, granitic and metavolcanic rocks. Below . the wilderness at Gisela, Tonto Creek runs through At 72.5 miles in length, Tonto Creek is a Strahler Pliocene to middle Miocene deposits and early fifth order stream and has a 955 sq. mi. watershed Pleistocene to latest Pliocene surficial deposits. at the confluence with the Salt River. Starting just Within the Tonto basin, there are several occur- below the Mogollon Rim at an altitude of 7,400 rences of barite (barium sulfate), a mineral that feet, the creek then descends through a steep often co-occurs with cinnabar (mercuric sulfide), as canyon, in places almost 1,000 feet deep within the well as mineable quantities of cinnabar itself. Hellsgate Wilderness. At the lower wilderness Publication Number: OFR 11-05 1 Figure 1. Tonto Creek, Arizona

2 SAMPLING, STANDARDS AND ANALYSIS piscivorous fish. No fish other than rainbow trout, Mercury speciation and analysis brown trout and desert suckers were found. Results All fish tissue samples referenced in this report are summarized in Table 1 and Figure 2 below. were analyzed for, and the results reported as, total In the Bear Flats area south of Camp Tontozona mercury (THg). The total mercury data was then the 11 rainbow trout taken had a mean Hg con- used as a surrogate for methylmercury in the risk centration of 0.2 mg/Kg with a range of 0.02 to 0.3 analysis. While methylmercury is generally consid- mg/Kg. Six brown trout had a mean concentration ered the more toxic fraction in consumable fish of 0.2 mg/Kg with a range of 0.1 to 0.3 mg/Kg. Four tissue, total mercury and methylmercury in fish desert suckers had a mean Hg concentration of 0.6 tissue are well correlated (Bloom, N.S. 1992, mg/Kg with a range of 0.4 to 0.7 mg/Kg. Maršálek et al. 2006, Kuwabara et al. 2007, Storelli From Tonto Narrows to Roosevelt Lake the 17 et al. 2003, Lasorsa and Allen-Gil 1995) with smallmouth bass taken had a mean tissue Hg con- methylmercury comprising ~95-99 percent of the centration of 1.5 mg/Kg with a range of 0.4 to 3.0 total mercury analyzed. Total mercury analysis is mg/Kg. 13 common carp had a mean Hg concen- also less complex, less expensive and allows long tration of 0.5 mg/Kg with a range of 0.3 to 0.8 term comparison with national and State data sets. mg/Kg. Four green sunfish had a mean Hg concen- These data sets are influenced by the condition tration of 1.0 mg/Kg with a range of 0.6 to 1.4 (relative weight (Wr) or “fatness”) of the fish. mg/Kg. Three black bullhead catfish had a mean concentration of 1.1 mg/Kg with a range of 0.6 to Sampling 1.9 mg/Kg. A single largemouth bass and a single In 2002, the U.S. Environmental Protection desert sucker had Hg concentrations of 0.4 and 0.6 Agency (USEPA) sampled fish from Tonto Creek just mg/Kg respectively. below the Hellsgate Wilderness Area as a part of the Regional Environmental Monitoring and Assessment Standards Program (REMAP). Five fish were taken without In the last surface water quality standards rule- recording species and categorized as either small or making approved January 2009, the State adopted large. The mean mercury concentration for all fish a fish tissue standard of 0.3 mg/Kg for methylmer- from this sample was 1.11 mg/Kg with a range of cury for protection of the fish consumption desig- 0.652 to 2.275 milligrams per kilogram (mg/Kg) nated use. This fish tissue standard was used in cal- (N=5). Due to flooding in Tonto Creek, fish were culating the lower safe limit in this advisory. The not again sampled until 2006. consumption advice contained in this document is Currently, the Arizona Department of based on a risk analysis derived using the USEPA Environmental Quality (ADEQ) and the Arizona reference dose for methylmercury (USEPA, 2002). Game and Fish Department (AGFD) work coopera- RISK ANALYSIS tively in the collection of fish for the fish consump- In aquatic ecosystems with a conducive water tion advisory program. Since 2006 fish in Tonto chemistry, (the right balance of sulfate, dissolved Creek were sampled on five occasions along three organic carbon, a favorable redox potential and sections of the creek by ADEQ and AGFD. A total bacteria population), methylation; which is the of eight different species were taken: smallmouth incorporation of mercury into an organic molecule, bass (Micropterus dolomieu), common carp takes place at a rapid rate. Once methylated, mer- (Cyprinus carpio), green sunfish (Lepomis cyanellus), cury moves through and up the food web quickly black bullhead catfish (Ameiurus melas), desert and becomes concentrated in high order predators sucker (Catostomus clarki) and largemouth bass such as largemouth or striped bass, northern pike (Micropterus salmoides) were taken in the section and/or walleye. Upon ingestion by humans, from Tonto Narrows upstream of Gisela to methylmercury is readily absorbed through the gas- Roosevelt Lake. Rainbow trout (Oncorhynchus trointestinal tract and easily penetrates the blood- mykiss), desert sucker and one brown trout (Salmo brain and placental barriers. While methylmercury trutta) were taken in the area of Bear Flats just has been linked to a variety of health effects, the upstream of the wilderness boundary. An extensive primary risk arises from its toxicity to the nervous survey for piscivorous fish was conducted in the system, including the brain. Most at risk are infants Bear Flats and Camp Tontozona portions of Tonto and unborn children whose mothers consume fish Creek to determine the presence or absence of containing methylmercury during pregnancy or 3 while nursing. Chronic exposure to methylmercury may cause gross cranial defects, cerebral palsy and at elevated concentrations can cause developmental a decrease in living fetuses. delays and learning disabilities, and acute exposures

Table 1. Mercury in fish filet tissue from Tonto Creek, Arizona

4 Figure 2. Mercury in fish filet tissue from Tonto Creek, Arizona TOXICOLOGY AND REFERENCE DOSE An RfD is an estimate of a daily oral exposure that is likely to be without any appreciable risk of adverse health effects. For determining safe rates of consumption, the EPA RfD of 0.0001 mg/Kg-day is used. This RfD is based on a study of women and children who episodically ate methylmercury tainted fish and pilot whale meat in the Faroe Islands and considers impairment of chil- dren’s neurological function that cause developmental Methylmercury is considered a Class C (possible) delays. Mean body weights for all age/sex classifica- human carcinogen due to increased incidence of tions are calculated using data from the National renal adenomas, adenocarcinomas and carcinomas Health and Nutrition Examination Survey observed in male mice. These effects were found in (NHANES) (Portier, et al., 2007). Total mercury the presence of profound nephrotoxicity caused by concentrations used in the risk calculation are the exposure to the toxicant and may be a conse- means for the individual species. quence of reparative changes in the cells. While methylmercury may not be a strong mutagen, it has POSSIBILITY OF ACUTE TOXICITY been shown to induce chromosomal aberrations. While developmental chronic toxicity is the Neurologic effects include erythism or “mad hatter major concern when considering mercury, it is also syndrome”, tremors, paresthesia, slowed brain important to address the possibility of acute toxicity. activity, memory disturbance and sleep disorders. Biokinetic modeling (Ginsberg and Toal, 2000) has (USEPA, 2002) predicted the elevation of certain biomarkers asso- ciated with neurodevelopmental effects as a result CALCULATION OF RISK FOR CHRONIC EXPOSURE of the consumption, during pregnancy, of a single While Arizona has a standard for methylmercury eight ounce fish meal at or above 2 mg/Kg in fish tissue, fish containing mercury can still be methylmercury. Using this concentration as a deci- part of a healthy diet if consumed at a rate that will sion making tool will allow an analysis of possible not cause mercury to accumulate to toxic concen- acute effects that may occur if a much larger than trations in the human body. To determine this rate, average fish were caught and consumed. Because the following formula is used: tissue mercury concentrations often correlate well with length and/or weight within a single fish species (Gewurtz, S. et al. 2011), ADEQ may be able to predict Hg concentrations in fish larger than those taken for analysis by correlating length with Hg and extrapolating out to State record length. Where: CRlim = daily consumption rate limit (Kg/day) Smallmouth bass taken from Tonto Creek had a RfD = national reference dose (mg/Kg/day) mean Hg concentration of 1.5 mg/Kg. Because the BW = body weight (Kg) calculated consumption rate was less than one meal Hg(t) = total mean mercury concentration per month for that species, the published consump- (mg/Kg per individual species) tion advice will be “no consumption”. For black bullhead catfish, no consumption is also advised for all age and sex classifications due to the high maximum concentration (1.9 mg/Kg) found in a specimen well 5 below State record length (420 mm). Green sunfish mouth structure and grazing/scraping feeding had a mean concentration of 1.0 mg/Kg with a max- behavior, it is rare that they can be successfully imum concentration of 1.4 mg/Kg occurring at less taken on hook and line. Also, due to the prevalence than 80% of the state record. Given this high max- of hard-to-remove bones, if caught, they are hard to imum concentration, no consumption is also prepare and consume. These factors along with the advised for all age and sex classifications. generally lower tissue concentrations of mercury The unlimited consumption advice for both trout found for this species in this study, it is considered species is based on tissue concentrations below the unlikely that they will present significant risk to the State standard for methylmercury (0.3 mg/Kg). angling population. Desert suckers are not considered in this analysis The following Table 2 contains consumption for several reasons. First, because of their subapical advice for the sport fish taken in this survey:

Table 2. Safe consumption limits for sport fish from Tonto Creek, Arizona

6 PROBABILITY OF CONSUMPTION was 0.00 cfs at the Gun Creek gauge, a “pinch It is important that the probability and, by infer- point” on the creek where bedrock pushes subflow ence, the possibility of consumption be addressed to the surface. in any fish consumption risk analysis. Also, while Tonto Creek also has three separate and distinct national default consumption rates are important sections that impact use and fishing pressure: for the calculation of risk for the general populace, Upper Tonto Creek, which is regularly stocked with they are often problematic when extrapolating risk rainbow trout from the AGFD fish hatchery near to vulnerable or underrepresented portions of the Tonto Springs and is considered a prime trout fish- population. For these reasons, this analysis address- ery by many anglers; Middle Tonto Creek, through es factors that may contribute to the possibility of the Hellsgate Wilderness, where fishing pressure is consumption rates in excess of the default and data restricted by difficult, non-motorized access; and from other studies where consumption rates in lower Tonto Creek where low (or no) flows, degraded excess of the default were found. These factors will landscape lacking shade and proximity to better be considered qualitatively in the risk analysis recreational fishing in Roosevelt Lake probably process. reduces fishing pressure (Marc Dahlberg, pers.com). Demographics Table 2. Safe consumption limits for sport fish from Tonto Creek, Arizona Relative to the Arizona and Maricopa County pop- ulation statistics, Gila County has a higher child- hood poverty and overall poverty rate, a lower medi- an income and birth rate and a lower overall popula- tion density. The lower population density does not necessarily present a lower risk to any one per- son or group of people. The only ameliorating influence of the lower pop- ulation would be the lower 1 Arizona Department of Health Services, 2009 number of persons exposed to that risk. FISHING PRESSURE ON TONTO CREEK SYNTHESIS AND CONCLUSIONS Tonto Creek is unregulated over its full length When determining whether to issue a fish and has a highly variable hydrograph. Between consumption advisory, a number of factors need to Tonto Spring and the point where the creek crosses be considered: the northern boundary of the Hellsgate Wilderness Factors that may discourage consumption or (upper Tonto Creek), annual flow is largely influ- mitigate the consequences of consumption include: enced by groundwater discharged into the water- • Relatively large distance between the stream and course by multiple springs. However, at its southern any major population center boundary, Tonto Creek enters Tonto Basin where • Low density of persons from ethnic groups with flows can downwell into the wide alluvial deposits. traditionally high fish consumption At the USGS gauging station on lower Tonto Creek, • Below average birth rate per 1,000 population monthly mean flows fluctuate between a high of • Low average flows in lower Tonto Creek 4,272 cubic feet per second (cfs) for a single month • Open, degraded watercourse not esthetically (January, 1993) to a low of less than 1 cfs for 15 pleasing separate months between January, 1990 and • Proximity to better recreational fishing in September, 2010. For six of those months the flow Roosevelt Lake 7 Factors that may promote consumption or exac- ADDITIONAL PROGRAM INFORMATION erbate the consequences of consumption include: Arizona Department of Environmental Quality • There are several areas consisting both of vaca- Water Quality Division – Fish Advisory Program tion/winter homes and year round residences 1110 W. Washington St. Phoenix, AZ 85007 Contact: Sam Rector within the vicinity of the creek. (602) 771-4536 or (800) 234-5677 Ext: 771-4536 • Tonto Creek contains resident populations of e-mail: [email protected] Web site: www.azdeq.gov large, predatory fish species with a higher potential to bioaccumulate methylmercury. References • Concentrations of methylmercury found in Bloom, N.S. 1992. On the Chemical Form of Mercury in certain species present a reasonable potential risk Edible Fish and Marine Invertebrate Tissue. Canadian Journal (if consumed) to all persons in general and children of Fisheries and Aquatic Science. 49: 1010-1017 and women of child bearing age in particular. Gewurtz, Sarah B., Satyendra, P. Bhavsar and Rachael Considering the rates of unemployment and the Fletcher, 2011. Influence of fish size and sex on mercury/PCB low median income found in Gila County, there concentration: Importance for fish consumption advisories Environment International 37: 2, 425-434. may be economic pressures encouraging the utilization of fish caught from Tonto Creek as an Ginsberg, G.L. and B. F. Toal. 2000. Development of a single- episodic supplemental protein source. Given that meal fish consumption advisory for methylmercury. Risk default consumption assumptions may underesti- Analysis. 20:41-47. mate the risk to sensitive populations and that the Kuwabara, J.S., Arai, Yuji, Topping, B.R., Pickering, I. J., and concentrations of methylmercury found in fish George, G.N., 2007. Mercury speciation in piscivorous fish tissue samples taken from Tonto Creek are in excess from mining-impacted reservoirs: Environmental Science and of the calculated lower safe limit and present a Technology 41, 2745-2749. potential risk to consumers, it is recommended that Lasorsa, B.K. and S. M. Allen-Gil. 1995. The methylmercury to a fish consumption advisory be instituted on Tonto total mercury ratio in marine, freshwater, and terrestrial organ- Creek as detailed below. isms: an overview. Water, Air and Soil Pollution. 80: 905-913. Marc Dahlberg, 2011. Personal communication, AZ Game For rainbow and brown trout caught in Tonto and Fish Department Creek upstream of the northern boundary of Hellsgate Wilderness: Maršálek, P., Z. Svobodová and T. Randák, 2006. Total Mercury and Methylmercury Contamination in Fish from Sites • Unlimited consumption for all groups along the Elbe River. Acta Veterinaria Brno. Journal of the University of Veterinary and Pharmaceutical Sciences in Brno, For smallmouth bass, green sunfish and black Czech Republic 75: 579-585 bullhead catfish from Tonto Creek downstream of Portier K.; Tolson, J.; Roberts, S., 2007 Body weight distribu- the northern boundary of Hellsgate Wilderness: tions for risk assessment. Risk Analysis 27(1)11-26.

• No consumption Storelli M.M.; Giacominelli-Stuffler R.; Storelli A.; D'Addabbo R.; Palermo C.; Marcotrigiano G.O., 2003. Survey of total For common carp from Tonto Creek downstream mercury and methylmercury levels in edible fish from the Adriatic Sea. Food Additives and Contaminants, Volume 20, of the northern boundary of Hellsgate Wilderness: Number 12, pp. 1114-1119(6) • Children younger than six years old: U.S. Census Bureau, 2009. Census Data for the State of No consumption Arizona. www.census.gov/census2000/states/az.html • Children between six and sixteen years of age: U.S. EPA, 2002. Integrated Risk Information System (IRIS) One 8 oz. (uncooked weight) fish meal per month toxicological review for methylmercury. USEPA, Washington, • All Adults (16 years or older): D.C. www.epa.gov/iris/ One 8 oz. (uncooked weight) fish meal per month

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