Geology topics

Fern A. Bullard

Publications and source records attributed to Fern A. Bullard.

6 recordsLinked to original sources

USGS2005

Selenium impacts on razorback sucker, Colorado: Colorado River: III. Larvae

Razorback sucker ( Xyrauchen texanus ) larvae from adults exposed to selenium at three sites near Grand Junction, Colorado, for 9 months were used in a 30-day waterborne and dietary selenium study. Selenium concentrations in water averaged <1.6 μg/L from 24-Road, 0.9 μg/L from Horsethief, 5.5 μg/L from Adobe Creek, and 10.7 μg/L from the North Pond. Selenium in dietary items averaged 2.7 μg/g in brine shrimp, 5.6 μg/g in zooplankton from Horsethief east wetland, 20 μg/g in zooplankton from Adobe Creek, and 39 μg/g in zooplankton from North Pond. The lowest survival occurred in larvae fed zooplankton rather than brine shrimp. Survival of larvae at Adobe Creek and North Pond was lower in site water than in reference water. Survival of brood stock larvae was higher than Horsethief larvae even though they received the same water and dietary treatments. Arsenic concentrations in brine shrimp may have resulted in an antagonistic interaction with selenium and reduced adverse effects in larvae. Deformities in larvae from North Pond were similar to those reported for selenium-induced teratogenic deformities in other fish species. Selenium concentrations of ⩾4.6 μg/g in food resulted in rapid mortality of larvae from Horsethief, Adobe Creek, and North Pond, and suggested that selenium toxicity in the Colorado River could limit recovery of this endangered fish.

Ecotoxicology and Environmental Safety↗

USGS2005

Reduced growth and survival of larval razorback sucker fed selenium-laden zooplankton

Four groups of larval razorback sucker, an endangered fish, were exposed to selenium-laden zooplankton and survival, growth, and whole-body residues were measured. Studies were conducted with 5, 10, 24, and 28-day-old larvae fed zooplankton collected from six sites adjacent to the Green River, Utah. Water where zooplankton were collected had selenium concentrations ranging from <0.4 to 78 μg/L, and concentrations in zooplankton ranged from 2.3 to 91 μg/g dry weight. Static renewal tests were conducted for 20 to 25 days using reference water with selenium concentrations of <1.1 μg/L. In all studies, 80–100% mortality occurred in 15–20 days. In the 28-day-old larvae, fish weight was significantly reduced 25% in larvae fed zooplankton containing 12 μg/g selenium. Whole-body concentrations of selenium ranged from 3.7 to 14.3 μg/g in fish fed zooplankton from the reference site (Sheppard Bottom pond 1) up to 94 μg/g in fish fed zooplankton from North Roadside Pond. Limited information prior to the studies suggested that the Sheppard pond 1 site was relatively clean and suitable as a reference treatment; however, the nearly complete mortality of larvae and elevated concentrations of selenium in larvae and selenium and other elements in zooplankton indicated that this site was contaminated with selenium and other elements. Selenium concentrations in whole-body larvae and in zooplankton from all sites were close to or greater than toxic thresholds where adverse effects occur in fish. Delayed mortality occurred in larvae fed the two highest selenium concentrations in zooplankton and was thought due to an interaction with other elements.

Ecotoxicology and Environmental Safety↗

USGS2002

Impact of selenium and other trace elements on the endangered adult razorback sucker

A study was conducted with endangered the razorback sucker ( Xyrauchen texanus ) to determine if environmental exposure to selenium in flooded bottomland sites affected survival, growth, and egg-hatching success. Adults were stocked at three sites adjacent to the Colorado River near Grand Junction, Colorado, in July 1996: hatchery ponds at Horsethief Canyon State Wildlife Area (referred to here as Horsethief; the reference site), a diked tertiary channel at Adobe Creek, and North Pond at Walter Walker State Wildlife Area (WWSWA). Fish were collected in April 1997 and spawned. After two spawnings adults from the three sites were held at Horsethief for an 86-day selenium depuration period. Selenium concentrations at Horsethief were 1.4–3.0 μg/L in water, 0.8–0.9 μg/g in sediment, 4.5 μg/g in muscle plug, and 6.0 μg/g in eggs; at Adobe Creek, <0.7–4.5 μg/L in water, 1.2–2.5 μg/g in sediment, 16–20 μg/g in zooplankton, 9.6 μg/g in muscle plug, and 40 μg/g in eggs; and at North Pond, 3.2–17 μg/L in water, 16–94 μg/g in sediment, 32–48 μg/g in zooplankton, 14 μg/g in muscle plug, and 55 μg/g in eggs. During the depuration period, when adults from Adobe Creek and North Pond were held at Horsethief, the fish lost 7%–13% of their selenium burden in 59 days and 14%–21% in 86 days. Larvae from North Pond adults had the most deformities, followed by Adobe Creek adults, with the fewest deformities found in the Horsethief adults.

Colorado↗

USGS2002

Toxicity of selenium and other elements in food organisms to razorback sucker larvae

Elevated selenium concentrations documented in water, sediment, and biota in irrigation drain water studies by U.S. Department of the Interior agencies and academia have raised concerns that selenium may be adversely affecting endangered fish in the upper Colorado River basin. The objective of the study was to determine the effects on endangered razorback sucker ( Xyrauchen texanus ) larvae from exposure to selenium and other trace elements in water and zooplankton collected from sites adjacent to the Colorado River near Grand Junction, CO. A 30-day study was initiated with 5-day-old larvae exposed in a 4×4 factor experiment with four food and four water treatments, and the biological endpoints measured were survival, growth, development, and whole-body residues of selenium. Mean selenium concentration in reference water (24-Road) was <0.7 μg/l, in reference food (brine shrimp) was 3.2 μg/g, at Horsethief was 1.6 μg/l in water and 6.0 μg/g in zooplankton, at Adobe Creek was 3.4 μg/l in water and 32 μg/g in zooplankton, and at Walter Walker was 13 μg/l in water and 52 μg/g in zooplankton. Although there were differences in concentrations of inorganic elements in water and biota among the three sites, selenium was apparently the only element elevated to concentrations of concern. Effects on survival were more prominent from dietary exposure compared to waterborne exposure. Selenium concentrations of ≥4.6 μg/g in food organisms adversely affected the survival of razorback sucker larvae. The onset of mortality in larvae exposed to food and water from Walter Walker seemed delayed compared to mortality in larvae exposed to food and water from Horsethief, which has been observed in two other studies. Elevated arsenic in one food source seemed to interact with selenium to reduce the toxic effects of selenium.

Colorado↗

USGS2000

Chronic toxicity and hazard assessment of an inorganic mixture simulating irrigation drainwater to razorback sucker and bonytail

We conducted two 90 day chronic toxicity studies with two endangered fish, razorback sucker and bonytail. Swim-up larvae were exposed in a reconstituted water simulating the middle Green River. The toxicant mixture simulated the environmental ratio and concentrations of inorganics reported in a Department of the Interior study for the mouth of Ashley Creek on the Green River, and was composed of nine elements. The mixture was tested at 1X, 2X, 4X, 8X, and 16X where X was the measured environmental concentration (2 μg/L arsenic, 630 μg/L boron, 10 μg/L copper, 5 μg/L molybdenum, 51 μg/L selenate, 8 μg/L selenite, 33 μg/L uranium, 2 μg/L vanadium, and 20 μg/L zinc). Razorback sucker had reduced survival after 60 days exposure to the inorganic mixture at 8X, whereas growth was reduced after 30 and 60 days at 2X and after 90 days at 4X. Bonytail had reduced survival after 30 days exposure at 16X, whereas growth was reduced after 30, 60, and 90 days at 8X. Swimming performance of razorback sucker and bonytail were reduced after 60 and 90 days of exposure at 8X. Whole-body residues of copper, selenium, and zinc increased in a concentration-response manner and seemed to be regulated at 90 days of exposure at 4X and lower treatments for razorback sucker, and at 8X and lower for bonytail. Adverse effects occurred in fish with whole-body residues of copper, selenium, and zinc similar to those causing similar effects in other fish species. Comparison of adverse effect concentrations with measured environmental concentrations showed a high hazard to the two endangered fish. Irrigation activities may be a contributing factor to the decline of these endangered fishes in the middle Green River.

Environmental Toxicology↗

USGS1990

Toxicity of organic selenium in the diet to chinook salmon

The toxicity of two organoselenium diets was evaluated in 90- to 120-d partial life cycle tests with two life stages of chinook salmon ( Oncorhynchus tshawytscha Walbaum). One of the diets contained fish meal made from high-selenium mosquitofish ( Gambusia affinis Baird and Girard) collected from the selenium-laden San Luis Drain, California (here termed SLD diet) and the other contained meal made from low-selenium mosquitofish (collected from a reference site) fortified with selenomethionine. A 90-d study was conducted with swim-up larvae in a water-simulating dilution of San Luis Drain water in a standardized fresh water; and a 120-d study was conducted with fingerlings 70-mm long in a water of similar quality but prepared with a standardized brackish water. After 90 d of exposure in the freshwater study, survival was reduced in fish fed ≥9.6 μg Se/g of either diet, and growth was reduced in fish fed ≥5.3 μg Se/g of SLD diet or ≥18.2 μg Se/g of selenomethionine diet. Reduced fish growth, whole-body concentrations of selenium and survival were strongly correlated to concentrations of selenium in both diets. After 120 d of exposure in the brackish-water study, survival was unaffected but growth was reduced in fish fed ≥18.2 μg Se/g of SLD diet or 35.4 μg Se/g of selenomethionine diet. After 120 d of dietary exposure, survival during a 10-d seawater challenge test was reduced in fish fed 35.4 μg Se/g of either diet. In this second dietary study, concentration—response relations were observed in both dietary treatments between the dietary concentrations of selenium and all three characteristics — fish growth, whole-body concentrations of selenium and survival in seawater.

Environmental Toxicology and Chemistry↗