Contaminant Concentrations in Water, Sediment, and Biota from Stone Lakes National Wildlife Refuge, 1997

By:
Carmen Thomas

U.S. Fish and Wildlife Service

Environmental Contaminants Division

Sacramento Fish and Wildlife Office

Sacramento, California

December, 1999

ABSTRACT

We measured standard water quality parameters and collected water, sediment, and biota samples from Stone Lakes National Wildlife Refuge and adjacent areas during March, April, and May, 1997. Water samples were analyzed for metals and metalloids; sediment and biota samples were analyzed for metals and metalloids, heavy metals, organochlorine pesticides, and PCB congeners. Water quality was good in Black-crown Lake, Lower Beach Lake, and the North arm of North Stone Lake. Water quality in Morrison Creek, South Stone Lake, and the South arm of North Stone Lake was somewhat impaired by elevated temperatures, elevated conductivity, or low dissolved oxygen.

Lead concentrations in water were elevated at Black-crown Lake, Morrison Creek, and Lower Beach Lake. Lead concentrations in biota exceeded the threshold for adverse effects at Black-crown Lake and Lower Beach Lake. Copper concentrations were also elevated in water from Black-crown Lake. Selenium concentrations in water were slightly elevated at Black-crown Lake and Lower Beach Lake. There were numerous guideline exceedences for heavy metals in sediments from all sites. Concentrations of arsenic, cadmium, chromium, copper, lead, nickel, and zinc were elevated in sediment from one or more sites. Mercury, selenium, organochlorine pesticides, and PCB concentrations were low in sediment samples from all sites.

Concentrations of metals and metalloids and heavy metals were low in fish fillets and waterbird eggs. Chromium concentrations in bullfrog tadpoles, inland silversides, mosquitofish, and white crappie were elevated. Copper concentrations detected in crayfish and bullfrog tadpoles were similar to concentrations linked to polluted waters. Concentrations of selenium, organochlorine pesticides, and PCBs in all biota were below levels that would cause adverse effects.

Morrison Creek and Lower Beach Lake were the most polluted waterbodies of those we studied, and should be monitored in the future. In addition, to maintain water quality that is consistent with the goal of the refuge, we suggest the initiation of a long-term monitoring program to track any changes in contaminant concentrations resulting from current and future land-use patterns around the refuge.

INTRODUCTION

California's Central Valley remains the most valuable waterfowl wintering habitat in North America, supporting 8-10 million migrating birds and 60% of the Pacific Flyway's wintering waterfowl and shorebirds (California Department of Fish and Game 1983, Heitmeyer et al. 1989). Of the 15 drainage basins in the Central Valley, the Sacramento-San Joaquin Delta is ranked second highest in biological value to Pacific Flyway waterbirds (U.S. Fish and Wildlife Service 1978). A large heron/egret/cormorant colony (great blue herons, black-crowned night-herons, snowy egrets, great egrets, double-crested cormorants) is present in the south arm of North Stone Lake. This colony supports approximately 268 nests and has been identified as the most inland nesting colony of cormorants on the Pacific coast (U.S. Fish and Wildlife Service, unpublished data). On May 10, 1994, during a routine nesting colonial waterbird survey, a cormorant nestling with a deformed bill (no lower mandible) was observed at North Stone Lake (U.S. Fish and Wildlife Service, unpublished data). During the surveys (February to June 1994), 238 total nests were counted, 55 of which were double-crested cormorant nests. An average of 2.4 cormorant young per nest was calculated. The number of fail-to-hatch cormorant eggs was not estimated at North Stone Lake.

A 1987-1988 study of Michigan Great Lakes colonial waterbirds found that 17 of 3,757 hatched cormorant chicks had developmental defects (frequency of 0.46%) (Kurita et al. 1987). At North Stone Lake, one deformed cormorant chick, of the approximate 132 cormorant chicks observed (55 nests x 2.4 young per nest), represents a frequency of 0.76% developmental defects. The 1987-1988 study also determined that only one in 40 (2.5%) cormorant embryos with a developmental defect was able to hatch and survive long enough to be found by an investigator (Kurita et al. 1987). Therefore, even one defective hatched chick can be indicative of a serious contaminant problem in a given area. The observed effects of the 1987-1988 Great Lakes study were attributed to PCBs, dioxin, and other organochlorine contaminants.

Stone Lakes National Wildlife Refuge (NWR) occurs in the lower Morrison Creek watershed, a large watershed that includes Laguna Creek, Morrison Creek, and Beach Lakes. All streams in the watershed drain into Lower Beach Lake and North and South Stone Lakes, therefore, polluted sediment, water, and toxins can accumulate there. Many commercial, industrial, and agricultural sources contribute runoff to the Morrison Creek drainage area (Environmental Science Associates 1996). In 1998, Morrison Creek was listed in the state's 303D list for diazinon. New commercial and housing developments have been approved by the County and began construction in 1996 on the eastern boundary of the Refuge. The developments discharge urban runoff and stormwater into two seasonal swales directly leading into North Stone Lake and will most likely increase the pollutant load entering Refuge waters. Based on this information, the 1992 Environmental Impact Statement (EIS) for the establishment of Stone Lakes as a National Wildlife Refuge stated that, "a water quality control plan will be developed and implemented for the Refuge." The objectives of this study were to: (1) determine contaminants that are present in water sources and on the refuge, (2) determine contaminant concentrations in waterbird eggs and chicks, and (3) identify potential areas of contaminant bioaccumulation.

STUDY AREA

In 1992, the Stone Lakes NWR was designated as the 505th unit of the National Wildlife Refuge system. To date, the USFWS has acquired fee title interest in 757 acres and manages almost 6,000 acres for the refuge, which is located approximately 10 miles south of Sacramento (Figure 1). Stone Lakes NWR is located in the Beach/Stone Lakes Basin, a remnant of California's once vast wetland complex that includes three major lakes (North Stone, South Stone, and Beach Lakes) and numerous smaller lakes and ponds. North Stone Lake of the Stone Lakes NWR supports large numbers of wintering waterfowl and resident birds and is recognized as part of the largest remaining complex of freshwater wetlands and natural communities in the Sacramento-San Joaquin Delta.

Sample collection

We collected water, sediment, and biota samples from Stone Lakes NWR and adjacent areas during March, April, and May, 1997 (Figure 2). Sampling locations, times, dates, and matrices collected are presented in Table 1. Water quality was measured at the beginning of each site visit, within an hour of the start time listed in Table 1.

We collected water samples by hand directly into polyethylene bottles and acidified them to pH < 2.00 in the field. Sediment was collected using either a ponar sampler or an Eckmann dredge. Three to five grabs were collected from a transect that bisected the waterbody. The sediment was thoroughly mixed and 2 composite samples were extracted. One sample was placed in a polyethylene bottle and analyzed for inorganics. The second sample was placed in a chemically cleaned glass jar (with a Teflon® lined lid) and analyzed for organochlorine compounds. Both water and sediment samples were transported on ice to the lab; water was refrigerated at 32C and sediment was frozen at -4C until submitted for analysis.

We used various means to collect biota. A Smith-Root backpack electroshocker, bag seine, and dip nets were used to collect invertebrates and fish. The means employed depended on the bottom type and depth of each water body. We separated biota by species and placed each species in chemically cleaned glass jars with Teflon ® lined lids. Avian eggs and chicks were collected from the nest by hand. We used an aerial lift (JLG articulated 60HA) to raise us to nest level. We also collected eggshells found beneath nest trees. All biota samples were transported on ice and frozen at -4C until submitted for chemical analyses.

Sample Processing

Twelve composite fish samples were prepared from specimens collected from North Stone Lake in 1994: 4 fillet composites and 8 whole body composites.

Fig 1

Fig 2

Length, breadth, mass, and volume were measured for each waterbird egg. We opened eggs at the air sac end to ascertain whether embryos were malpositioned and late stage embryos were examined for abnormalities. Eggs were then opened longitudinally and contents were placed in chemically cleaned jars and frozen at -4C. Eggshells were rinsed with deionized water and air dried at room temperature for at least 30 days. We used a rounded-tip drill press (Comparator) to measure shell thickness on harvested shells, and a rounded-edge micrometer to measure shell thickness on scavenged eggs. The Comparator requires shells to be cut longitudinally, and the brittleness of the scavenged eggshells precluded cutting them. Ratcliffe Indices (Ratcliffe 1970) were calculated for all shells and provide an indication of overall egg strength expressed as grams per square millimeter.

Transport and Analysis

Sediment and biota samples were sent to analytical labs in securely padded coolers on dry ice. Water samples were sent in securely padded coolers on blue ice. Environmental Trace Substance Lab (ETSL) conducted the inorganic analysis of the fish collected in 1994. Research Triangle Institute (RTI) conducted the metal scans, and Mississippi State Chemical Laboratory (MSCL) conducted the organic analyses of the 1997 samples. Sample spikes, blanks, and duplicates were run with samples for quality control. Results were not corrected for percent recovery (Appendix A).

Samples were prepared for inorganic analyses using nitric perchloric digestion (Research Triangle Institute 1994a). With the exception of arsenic (As), mercury (Hg), and selenium (Se), concentrations of all metals and metalloids were determined via inductively coupled plasma analysis (ICP) using a Leeman Lab PS2000 (Research Triangle Institute 1994b). A Perkin-Elmer Z3030 Atomic Absorption spectrometer was used to determine As concentrations in all matrices (Research Triangle Institute 1992). The method detection limit was 6 mg/L in water and 0.5 g/g in sediment and biota. Hg concentrations were determined via cold vapor atomic absorption using a Leeman Labs PS 200 automated mercury analyzer (Research Triangle Institute 1995). The method detection limit was 0.1 g/L in water and 0.01 g/g in sediment and biota. Se concentrations were determined via ICP-MS (Thompson and Grohse 1996). The methold detection limit was 1.0 g/L in water and 0.1 g/g in sediment.

Samples were prepared for organic analysis using an Accelerated Solvent Extractor 22 ml cell and petroleum ether digestion (Method 3545, U.S. Environmental Protection Agency 1996a). Florisil and silica columns were used for sample cleanup, and OC concentrations were determined via electron capture gas chromatography (GC) using a Varian 3600 GC equipped with 30M megabore columns (Mississippi State Chemical Lab 1997a, 1997b). PCB congeners were determined using a Varian 3400 GC equipped with a 60M DB-5 0.25 ID capillary column (Mississippi State Chemical Lab 1997a). The method detection limit was 5.0 ng/g for each congener.

Data Interpretation

Compounds that were not detected were assigned the value of one-half of the detection limit for computational purposes. Concentrations of metals and metalloids in water samples are reported as total recoverable analyte. Contaminant concentrations detected in this study were evaluated by comparisons to criteria, guidelines, and other research to determine whether concentrations could be hazardous to fish and wildlife. Criteria for hardness-sensitive metals were calculated using formulae provided by the Environmental Protection Agency (1996b). These formulae require input for hardness (as calcium carbonate) of a given waterbody. We used a value of 97 mg/L (as calcium carbonate) that was measured in Morrison Creek during April of 1997 (Sacramento Regional Wastewater Treatment Plant, unpubl. data). Guidelines that will be used in data interpretation for all matrices are explained in appendix B.

RESULTS

Overall, water quality was fairly good in Black-crown Lake, Lower Beach Lake, and the North arm of North Stone Lake (Table 2). Water quality in Morrison Creek, South Stone Lake, and the

South arm of North Stone Lake was somewhat impaired by elevated temperatures, elevated conductivity, or low dissolved oxygen. Electrical conductivity of Black-crown Lake, Morrison

Creek, and North Stone Lake were similar, and ranged from 141.5 to 196 mhos/cm. Waters of Lower Beach Lake and South Stone Lake had higher conductivities and ranged from 308 to 678 mhos/cm. Dissolved oxygen levels also varied. Morrison Creek and the South arm of North Stone Lake had very low dissolved oxygen, below 2 mg/L. With the exception of the East arm of South Stone Lake (4.02 mg/L), the remaining waterbodies had acceptable levels of DO (5.65 to 9.35). All waterbodies had similar pH which ranged from 6.7 in Morrison Creek near Lower Beach Lake to 8.15 in the Northeast arm of South Stone Lake. Temperature was between 19.65 and 21.85C for all waters except South Stone Lake. Temperature in South Stone Lake was markedly higher, from 24.48C in the main body up to 35.50 C in the East arm.

Inorganics

A trace element scan for 18 compounds was conducted on all matrices. In water samples 16 of those compounds were above detection limits; cadmium and beryllium were not detected at any study site (Table 3). Concentrations of aluminum, chromium, copper, iron, lead, nickel, selenium, and zinc were higher in water samples from Black-crown Lake and Lower Beach Lake relative to samples collected from North and South Stone Lake. Concentrations of boron, magnesium, manganese, and strontium were higher in North and South Stone Lake samples. Sacramento Regional Wastewater Treatment Plant personnel collected water samples from Morrison Creek and analyzed them for arsenic, copper, lead, mercury, and zinc. Copper, lead, and zinc levels in Morrison Creek were similar to those in Black-crown Lake and Lower Beach Lake.

Fillets from common carp and white catfish collected in 1993 were analyzed for metals and metalloids. In addition, fillets from common carp, white catfish, and Sacramento blackfish and whole body clams collected in 1993 were analyzed for mercury. In the common carp and white catfish fillets, concentrations of arsenic, boron, beryllium, cadmium,molybdenum, nickel, and vanadium were below detection limits. Concentrations of chromium, copper, manganese, lead, selenium, and strontium were slightly higher in the catfish compared to the carp. Higher levels of iron and zinc were detected in carp. Of the three species submitted for mercury analysis, Sacramento blackfish fillets contained the highest concentrations (common carp, 0.4 g/g; white catfish, 0.75 g/g and Sacramento blackfish, 0.93 g/g dry weight). Clam tissue contained low concentrations of mercury (0.04 g/g dry weight).

Trace element concentrations in the 1997 fillets were generally low (Table 4). Concentrations of arsenic, boron, cadmium, molybdenum, lead, and vanadium were below detection limits. Of the three species submitted for analysis, carp fillets contained the highest levels of metals and metalloids. Channel catfish fillets contained the lowest concentrations. Patterns of trace element concentrations differed between crayfish and bluegills (Table 5). Trace element concentrations were generally highest in crayfish collected from North Stone Lake. In contrast, trace element concentrations in bluegills from Morrison Creek and Lower Beach Lake were generally higher than concentrations detected at other sites. The lowest trace element concentrations generally were detected in crayfish from Lower Beach Lake and in bluegills from North Stone Lake. Beryllium was not detected in crayfish or bluegills from any site.

Concentrations of all 18 metals and metalloids were above detection limits in bullfrog tadpoles collected from Lower Beach Lake and South Stone Lake. With the exception of mercury and selenium, tadpoles typically had the highest concentrations relative to the rest of the aquatic biota. Of the fish, the highest trace element concentrations were always found in inland

With the exception of 1 goldfish from Black-crown Lake, no lesions were apparent on any fish we captured. The goldfish had a dime-size lesion just behind its operculum.

Several metals and metalloids were below detection limits in waterbird eggs, including arsenic, boron, beryllium, cadmium, chromium, nickel, and vanadium (Table 6). Copper, iron, magnesium, mercury, molybdenum, and zinc exhibited similar patterns of concentration in the waterbirds, with higher concentrations in cormorant and heron eggs relative to egret eggs. Mercury concentrations varied in waterbird eggs, with species means of 0.53, 0.63, and 1.25 g/g for egrets, herons, and cormorants, respectively. Selenium concentrations in eggs ranged from 2.6 to 4.69 g/g, with the highest concentrations present in heron eggs. Concentrations of arsenic, boron, beryllium, cadmium, and lead were not detected in great blue heron chicks. Of the 12 metals and metalloids detected in both heron eggs and chicks, concentrations of 11 compounds were significantly greater in chicks (P_1-tail = 0.03). Only molybdenum and selenium concentrations were greater in eggs.

Organochlorine Pesticides

Ten of 22 OCs were detected at low levels in waterbird eggs (Table 8). Heptachlor epoxide, o,p'-DDT, p,p'-DDD and p,p'-DDT were occasionally present in eggs, but the frequency of detections were insufficient for calculating a geometric mean. With the exception of p,p'-DDE, all detected OCs were present in concentrations <1 g/g. Of the OCs analyzed, p,p'-DDE concentrations were highest, but were not significantly different among species (P>0.30). DDE concentrations were slightly higher in double-crested cormorants than in great blue herons and