The acute toxicity of cadmium, copper, and zinc to white sturgeon (Acipenser transmontanus) and rainbow trout (Oncorhynchus mykiss) were determined for 7 developmental life stages in flow-through water-only exposures. Metal toxicity varied by species and by life stage. Rainbow trout were more sensitive to cadmium than white sturgeon across all life stages, with median effect concentrations (hardness-normalized EC50s) ranging from 1.47 µg Cd/L to 2.62 µg Cd/L with sensitivity remaining consistent during later stages of development. Rainbow trout at 46 d posthatch (dph) ranked at the 2nd percentile of a compiled database for Cd species sensitivity distribution with an EC50 of 1.46 µg Cd/L and 72 dph sturgeon ranked at the 19th percentile (EC50 of 3.02 µg Cd/L). White sturgeon were more sensitive to copper than rainbow trout in 5 of the 7 life stages tested with biotic ligand model (BLM)-normalized EC50s ranging from 1.51 µg Cu/L to 21.9 µg Cu/L. In turn, rainbow trout at 74 dph and 95 dph were more sensitive to copper than white sturgeon at 72 dph and 89 dph, indicating sturgeon become more tolerant in older life stages, whereas older trout become more sensitive to copper exposure. White sturgeon at 2 dph, 16 dph, and 30 dph ranked in the lower percentiles of a compiled database for copper species sensitivity distribution, ranking at the 3rd (2 dph), 5th (16 dph), and 10th (30 dph) percentiles. White sturgeon were more sensitive to zinc than rainbow trout for 1 out of 7 life stages tested (2 dph with an biotic ligand model–normalized EC50 of 209 µg Zn/L) and ranked in the 1st percentile of a compiled database for zinc species sensitivity distribution. Environ Toxicol Chem 2014;33:2259–2272. © 2014. The Authors. This article is a US government work and, as such, is in the public domain in the United States of America. Environmental Toxicology and Chemistry published byWiley Periodicals, Inc. on behalf of SETAC. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.

Abstract-Studies were conducted to determine the interactive toxicity of a water-accommodated fraction (WAF) of a weathered middle distillate petroleum and solar radiation to an estuarine organism, the tidewater silverside (Menidia beryllina). Juvenile silversides were monitored for survival and growth during a 7-d static renewal exposure to dilutions of WAFs of an environmentally weathered oil collected in the vicinity of an abandoned oil field in California. Ultraviolet (UV) treatments were based on incident sunlight intensity and spectra measured at this site. Exposure to UV alone was not lethal to the fish, and WAF in the absence of UV was toxic at the highest total petroleum hydrocarbon (TPH) concentration (3.03 mg/L) after 96 h of exposure. Water-accommodated fractions toxicity increased significantly with increasing UV irradiance and duration of exposure. The 7-d LC50 concentrations for the control, low, medium, and high irradiance were 2.84, 1.27, 0.93, and 0.51 mg/L TPH, respectively. Significant mortality occurred among fish previously exposed to WAF in the absence of irradiance, whereas WAF toxicity was unaffected by UV exposure prior to the toxicity test. Thus, the mode of action is a photosensitization of the accumulated petroleum residue rather than a photoactivation of WAF. Chemical analysis indicates that the WAF contains limited amounts of polycyclic aromatic hydrocarbons (PAHs) known to be photoenhanced, suggesting that other constituents may be responsible for the observed photoenhanced toxicity.

Abstract-The spectra and intensity of solar radiation (solar spectral irradiance [SSI]) was quantified in selected aquatic habitats in the vicinity of an oil field on the California coast. Solar spectral irradiance measurements consisted of spectral scans (280-700 nm) and radiometric measurements of ultraviolet (UV): UVB (280-320 nm) and UVA (320-400 nm). Solar spectral irradiance measurements were taken at the surface and at various depths in two marsh ponds, a shallow wetland, an estuary lagoon, and the intertidal area of a high-energy sandy beach. Daily fluctuation in SSI showed a general parabolic relationship with time; maximum structure-activity relationship (SAR) was observed at approximate solar noon. Solar spectral irradiance measurements taken at 10-cm depth at approximate solar noon in multiple aquatic habitats exhibited only a twofold variation in visible light and UVA and a 4.5-fold variation in UVB. Visible light ranged from 11,000 to 19,000 W/cm 2 , UVA ranged from 460 to 1,100 W/cm 2 , and UVB ranged from 8.4 to 38 W/cm 2 . In each habitat, the attenuation of light intensity with increasing water depth was differentially affected over specific wavelengths of SSI. The study results allowed the development of environmentally realistic light regimes necessary for photoenhanced toxicity studies.

White sturgeon (Acipenser transmontanus) populations throughout western North America are in decline, likely as a result of overharvest, operation of dams, and agricultural and mineral extraction activities in their watersheds. Recruitment failure may reflect the loss of early-life stage fish in spawning areas of the upper Columbia River, which are contaminated with metals from effluents associated with mineral-extraction activities. Early-life stage white sturgeon (A. transmontanus) from the Columbia River and Kootenai River populations were exposed to copper during 96-h flow-through toxicity tests to determine their sensitivity to the metal. Similar tests were conducted with rainbow trout (RBT [Oncorhynchus mykiss]) to assess the comparative sensitivity of this species as a surrogate for white sturgeon. Exposures were conducted with a water quality pH 8.1-8.3, hardness 81-119 mg/L as CaCO(2), and dissolved organic carbon 0.2-0.4 mg/L. At approximately 30 days posthatch (dph), sturgeon were highly sensitive to copper with median lethal concentration (LC(50)) values ranging from 4.1 to 6.8 μg/L compared with 36.5 μg/L for 30 dph RBT. White sturgeon at 123-167 dph were less sensitive to copper with LC(50) values ranging from 103.7 to 268.9 μg/L. RBT trout, however, remained more sensitive to copper at 160 dph with an LC(50) value of 30.9 μg/L. The results indicate that high sensitivity to copper in early-life stage white sturgeon may be a factor in recruitment failure occurring in the upper Columbia and Kootenai rivers. When site-specific water-quality criteria were estimated using the biotic ligand model (BLM), derived values were not protective of early-life stage fish, nor were estimates derived by water-hardness adjustment.

The acute toxicity of cadmium (Cd), copper (Cu), and zinc (Zn) to white sturgeon (Acipenser transmontanus) and rainbow trout (Oncorhynchus mykiss) was determined for seven developmental early life stages in flow-through wateronly exposures. Test waters consisted of five concentrations of each metal and a control. Nominal concentrations ranged from 0.01-600 micrograms per liter (µg/L) for cadmium, 0.1-300 µg/L for copper, and 0.4-10,000 µg/L for zinc, with higher exposure concentrations tested with older life stages. Exposures were performed in a water with a hardness of about 100 milligram per liters (mg/L) (as calcium chloride (CaCO 3)) and dissolved organic carbon of about 0.4 mg/L. Sturgeon were tested at 2, 16, 30, 44, 61, 72, and 89 dayspost-hatch (dph) and trout were tested at 1, 18, 32, 46, 60, 74, and 95 dph. Metal toxicity varied by species and by life stage. The 50-percent lethal concentrations (LC50) were based on mortality; whereas 50-percent effect concentrations (EC50s) were based on mortality, loss of equilibrium, and immobilization. The EC50s were used in comparisons with nationally recommended water-quality criteria (WQC) or to Washington State water-quality standards (WQS). Test acceptability requirement of greater than or equal to (≥)90 percent control survival was achieved in all exposures with the exception of 16-dph sturgeon exposures where control survival was 65 to 80 percent (hence, the EC50 for 16-dph sturgeon was classified as nondefinitive effect concentrations); however, despite the low control survival, the reductions in the survival of exposed 16-dph sturgeon were concentration dependent. Rainbow trout were more sensitive to cadmium than sturgeon across all life stages with LC50s ranging from 2.77 to greater than (>)49.4 micrograms cadmium per liter (µg Cd/L) with sensitivity remaining consistent during later stages of development (18-95 dph). Sturgeon LC50s for cadmium ranged from >47.2 to >355 µg Cd/L with sensitivity increasing during later stages of development (30-89 dph). The LC50 endpoint 6 Acute and Chronic Sensitivity of White Sturgeon and Rainbow Trout to Cadmium, Copper, Lead, or Zinc State WQS. For sturgeon aged 2 dph, the EC50 was below the WQC for copper and was below the Washington State WQS for all life stages tested. Although classified a nondefinitive effect concentration because of elevated 4-d control mortality, the EC50 for sturgeon at age 16 dph also fell below the WQC and Washington State WQS for copper. Sturgeon at 2 dph was the only life stage where the EC50 essentially was equal to the WQC and fell below the Washington State WQS for zinc. Results of this study will be submitted for consideration as part of a baseline ecological risk assessment being performed at the upper Columbia River in eastern Washington State.