Effects of in situ selenium exposure and maternal transfer on survival and deformities of brown trout (Salmo trutta) fry.

Offspring of wild adult brown trout exposed to a range of Se concentrations were reared in a laboratory setting to primarily assess effects on survival and deformities. Maternal whole-body Se concentrations ranged from 4.7 to 22.

Influence of Varying Water Quality Parameters on the Acute Toxicity of Silver to the Freshwater Cladoceran, Ceriodaphnia dubia.

The acute toxicity of silver to Ceriodaphnia dubia was investigated in laboratory reconstituted waters as well as in natural waters and reconstituted waters with natural organic matter. The water quality characteristics of the laboratory reconstituted waters were systematically varied. The parameters that demonstrated an ability to mitigate the acute toxic effects of silver were chloride, sodium, organic carbon, and chromium reducible sulfide.

The interactive toxicity of cadmium, copper, and zinc to Ceriodaphnia dubia and rainbow trout (Oncorhynchus mykiss).

Traditionally, aquatic toxicity studies examine the toxicity of a single chemical to an organism. Organisms in nature, however, may be exposed to multiple toxicants. Given this is a more realistic exposure scenario in situ, the authors sought to understand the interactive toxicity of multiple metals to aquatic organisms.

Identifying the cause of toxicity in an algal whole effluent toxicity study - an unanticipated toxicant.

Toxicity was observed in whole effluent toxicity (WET) studies with the freshwater alga, Pseudokirchneriella subcapitata, in three consecutive monthly studies, (NOEC=50-75%). Toxicity was not observed to Ceriodaphnia dubia or the fathead minnow, Pimephales promelas in concurrent studies. Selected toxicity identification evaluation (TIE) tests were conducted in a tiered approach to eliminate possible toxicants and progressively identify the causative agent.

The effect of food on the acute toxicity of silver nitrate to four freshwater test species and acute-to-chronic ratios.

Acute silver toxicity studies were conducted with and without food for four common freshwater test species: Daphnia magna, Ceriodaphnia dubia, Pimephales promelas (fathead minnow-FHM), and Oncorhynchus mykiss (rainbow trout-RBT) in order to generate acute-to-chronic ratios (ACR). The studies were conducted similarly (i.e.

Reprint of "Chronic toxicity of silver nitrate to Ceriodaphnia dubia and Daphnia magna, and potential mitigating factors".

We investigated the chronic toxicity of Ag, as silver nitrate, using two freshwater aquatic cladoceran species, Ceriodaphnia dubia and Daphnia magna, to generate data for the development of a chronic ambient water quality criterion for Ag. Preliminary studies with C. dubia showed variable results which were related to the equilibration time between food and silver.

Comparison of short-term chronic and chronic silver toxicity to fathead minnows in unamended and sodium chloride-amended waters.

The chronic (early life stage [ELS]) and short-term chronic (STC) toxicity of silver (as silver nitrate) to fathead minnows (FHM) was determined concurrently in flow-through exposures (33 volume additions/d). Paired ELS (approximately 30 d) and STC (7 d) studies were conducted with and without the addition of 60 mg/L Cl (as NaCl). The paired studies in unamended water were later repeated using standard flow conditions (9 volume additions/d).

Effects of sodium chloride on chronic silver toxicity to early life stages of rainbow trout (Oncorhynchus mykiss).

The chronic (early life stage) toxicity of silver to rainbow trout (Oncorhynchus mykiss) was determined in flow-through exposures. Rainbow trout embryos were exposed to silver (as AgNO3) from 48 h or less postfertilization to 30 d postswimup in soft water in the presence and absence of 49 mg/L of NaCl (30 mg/L of Cl). The studies determined effect levels for rainbow trout exposed throughout an extended development period and assessed possible protective effects of sodium chloride.

Chronic toxicity of silver nitrate to Ceriodaphnia dubia and Daphnia magna, and potential mitigating factors.

We investigated the chronic toxicity of Ag, as silver nitrate, using two freshwater aquatic cladoceran species, Ceriodaphnia dubia and Daphnia magna, to generate data for the development of a chronic ambient water quality criterion for Ag. Preliminary studies with C. dubia showed variable results which were related to the equilibration time between food and silver.

Effect of culture water hardness on the sensitivity of Ceriodaphnia dubia to copper toxicity.

We examined whether the sensitivity of Ceriodaphnia dubia to copper toxicity was influenced by the hardness of the water in which they were reared or in which they were exposed. Organisms cultured in very hard water were 1.5-fold less sensitive to copper than those in moderately hard water.

The biotic ligand model: a historical overview.

During recent years, the biotic ligand model (BLM) has been proposed as a tool to evaluate quantitatively the manner in which water chemistry affects the speciation and biological availability of metals in aquatic systems. This is an important consideration because it is the bioavailability and bioreactivity of metals that control their potential to cause adverse effects. The BLM approach has gained widespread interest amongst the scientific, regulated and regulatory communities because of its potential for use in developing water quality criteria (WQC) and in performing aquatic risk assessments for metals.

Evaluating the role of ion composition on the toxicity of copper to Ceriodaphnia dubia in very hard waters.

The mitigating effect of increasing hardness on metal toxicity is reflected in water quality criteria in the United States over the range of 25-400 mgl(-1) (as CaCO(3)). However, waters in the arid west of the US frequently exceed 400 mgl(-1) hardness, and the applicability of hardness-toxicity relationships in these waters is unknown. Acute toxicity tests with Ceriodaphnia dubia were conducted at hardness levels ranging from approximately 300 to 1,200 mgl(-1) using reconstituted waters that mimic two natural waters with elevated hardness: (1) alkaline desert southwest streams (Las Vegas Wash, NV), and (2) low alkalinity waters from a CaSO(4)-treated mining effluent in Colorado.

The effect of calcium and magnesium ratios on the toxicity of copper to five aquatic species in freshwater.

While it is generally accepted that water hardness affects copper toxicity, the major ions that contribute to water hardness (calcium [Ca] and magnesium [Mg]) may affect copper toxicity differently. This is important because the Ca:Mg ratio in standard laboratory-reconstituted waters often differs from the ratio in natural surface waters. Copper toxicity was assessed for five different aquatic species: rainbow trout (RBT), fathead minnow (FHM), Ceriodaphnia dubia, Daphnia magna, and an amphipod (Gammarus sp.