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2.
Environ Toxicol Chem ; 33(11): 2621-7, 2014 Nov.
Article in English | MEDLINE | ID: mdl-25132451

ABSTRACT

Canada has an interim water-quality guideline for fluoride for protection of freshwater aquatic life that dates from 2002, and 1 Canadian province has a different interim water-quality guideline for fluoride that dates to 1995. The United States does not have a national benchmark for fluoride in freshwater, and only 1 US state has such a benchmark. There are no other national or regional benchmarks for fluoride chronic toxicity in freshwater. In the present study, available data on the acute and chronic toxicity of fluoride to freshwater aquatic life were compiled and reviewed. Acute toxicity was reported to occur at concentrations ranging from 11.5 to >800 mg/L fluoride (F(-) ). The majority of chronic effects occur at concentrations between 1.8 mg/L and 195 mg/L. A total of 10 chronic studies representing 16 species (5 fish, 7 invertebrates, and 4 algae/aquatic plants) were used to derive a chronic effects benchmark of 1.94 mg/L F(-) , applying the species sensitivity distribution approach.


Subject(s)
Environmental Monitoring/standards , Fluorides/analysis , Fresh Water , Phosphates/analysis , Water Pollutants, Chemical/analysis , Animals , British Columbia , Canada , Environmental Monitoring/methods , Fishes , Invertebrates , Plants , Species Specificity , United States
3.
Environ Toxicol Chem ; 33(8): 1885-93, 2014 Aug.
Article in English | MEDLINE | ID: mdl-24832019

ABSTRACT

In vitro biotransformation assays are currently being explored to improve estimates of bioconcentration factors of potentially bioaccumulative organic chemicals in fish. The present study compares thin-film and solvent-delivery dosing techniques as well as single versus multiple chemical dosing for measuring biotransformation rates of selected polycyclic aromatic hydrocarbons in rainbow trout (Oncorhynchus mykiss) liver S9. The findings show that biotransformation rates of very hydrophobic substances can be accurately measured in thin-film sorbent-dosing assays from concentration-time profiles in the incubation medium but not from those in the sorbent phase because of low chemical film-to-incubation-medium mass-transfer rates at the incubation temperature of 13.5 °C required for trout liver assays. Biotransformation rates determined by thin-film dosing were greater than those determined by solvent-delivery dosing for chrysene (octanol-water partition coefficient [KOW ] =10(5.60) ) and benzo[a]pyrene (KOW =10(6.04) ), whereas there were no statistical differences in pyrene (KOW =10(5.18) ) biotransformation rates between the 2 methods. In sorbent delivery-based assays, simultaneous multiple-chemical dosing produced biotransformation rates that were not statistically different from those measured in single-chemical dosing experiments for pyrene and benzo[a]pyrene but not for chrysene. In solvent-delivery experiments, multiple-chemical dosing produced biotransformation rates that were much smaller than those in single-chemical dosing experiments for all test chemicals. While thin-film sorbent-phase and solvent delivery-based dosing methods are both suitable methods for measuring biotransformation rates of substances of intermediate hydrophobicity, thin-film sorbent-phase dosing may be more suitable for superhydrophobic chemicals.


Subject(s)
Biological Assay/methods , Liver/metabolism , Oncorhynchus mykiss/metabolism , Organic Chemicals/chemistry , Organic Chemicals/metabolism , Animals , Benzo(a)pyrene/chemistry , Benzo(a)pyrene/metabolism , Biotransformation , Chrysenes/chemistry , Chrysenes/metabolism , Hydrophobic and Hydrophilic Interactions , Polycyclic Aromatic Hydrocarbons/chemistry , Polycyclic Aromatic Hydrocarbons/metabolism , Temperature , Water/chemistry
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