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San Diego, CA, United States

Elphick J.R.,Nautilus Environmental | Chapman P.M.,Vancouver
Environmental Toxicology and Chemistry | Year: 2015

There are no national water-quality guidelines for strontium for the protection of freshwater aquatic life in North America or elsewhere. Available data on the acute and chronic toxicity of strontium to freshwater aquatic life were compiled and reviewed. Acute toxicity was reported to occur at concentrations ranging from 75mg/L to 15000mg/L. The majority of chronic effects occurred at concentrations above 11mg/L; however, calculation of a representative benchmark was confounded by results from 4 studies indicating that chronic effects occurred at lower concentrations than all other studies, in 2 cases below background concentrations reported for US and European streams. Two of these studies, including 1 reporting effects below background concentrations, were repeated and found not to be reproducible; chronic effects occurred at considerably higher strontium concentrations than in the original studies. Studies with narrow-mouthed toad and goldfish were not repeated; both studies reported chronic effects below background concentrations, and both studies had been conducted by the authors of 1 of the 2 studies that were repeated and shown to be nonreproducible. Studies by these authors (3 of the 4 confounding studies), conducted over 30 yr ago, lacked detail in reporting of methods and results. It is thus likely that repeating the toad and goldfish studies would also have resulted in a higher strontium effects concentration. A strontium chronic effects benchmark of 10.7mg/L that incorporates the results of additional testing summarized in the present study is proposed for freshwater environments. © 2014 SETAC. Source

McDonald B.G.,Golder Associates | deBruyn A.M.,Golder Associates | Elphick J.R.,Nautilus Environmental | Davies M.,Hatfield Consultants | And 2 more authors.
Environmental Toxicology and Chemistry | Year: 2010

Gametes were collected from Dolly Varden char (Salvelinus malma) from waterbodies in a region exposed to mining-related selenium (Se) releases in British Columbia, Canada. Fertilized eggs were incubated in a laboratory and deformities were assessed on newly-hatched alevins using a graduated severity index. No effects were observed on egg or alevin survival or larval weight across the studied exposure range of 5.4 to 66 mg/kg dry weight in egg. Length of some larvae was reduced at the highest egg Se concentrations and a clear residue-response relationship was observed for larval deformity. The egg concentration corresponding to a 10% increase in the frequency of deformity (EC10) was 54 mg/kg dry weight, which is substantially higher than reported for other cold-water fish species. © 2010 SETAC. Source

Elphick J.R.,Nautilus Environmental | Davies M.,Hatfield Consultants | Gilron G.,Teck Resources Ltd | Canaria E.C.,Nautilus Environmental | And 2 more authors.
Environmental Toxicology and Chemistry | Year: 2011

Elevated concentrations of sulfate occur commonly in anthropogenically impacted and natural waters. However, water quality guidelines (WQG) have not been developed in many jurisdictions, and chronic toxicity data are scarce for this anion. A variety of test organisms, including species of invertebrate, fish, algae, moss, and an amphibian, were tested for chronic toxicity to develop a robust dataset that could be used to develop WQGs. As an example of how these data might be used to establish guidelines, calculations were performed using two standard procedures: a species sensitivity distribution (SSD) approach, following methods employed in developing Canadian WQGs, and a safety factor approach, according to procedures typically used in the development of provincial WQGs in British Columbia. The interaction of sulfate toxicity and water hardness was evaluated and incorporated into the calculations, resulting in separate values for soft (10-40 mg/L), moderately hard (80-100 mg/L) and hard water (160-250 mg/L). The resulting values were 129, 644, and 725 mg/L sulfate, respectively, following the SSD approach, and 75, 625, and 675 mg/L sulfate, following the safety factor approach. © 2010 SETAC. Source

Elphick J.R.,Nautilus Environmental | Bergh K.D.,Rescan Environmental Services | Bailey H.C.,Nautilus Environmental
Environmental Toxicology and Chemistry | Year: 2011

Toxicity tests using nine freshwater species (Ceriodaphnia dubia, Daphnia magna, Oncorhynchus mykiss, Pimephales promelas, Lumbriculus variegatus, Tubifex tubifex, Chironomus dilutus, Hyallela azteca, and Brachionus calyciflorus) were conducted to evaluate their sensitivity to chloride. Acute-to-chronic ratios (ACRs) from these tests indicate the ACR of 7.59 employed by the United States Environmental Protection Agency (U.S. EPA) in deriving its water quality guideline for chloride may be conservative; a revised ACR of 3.50 is presented here. The endpoints used to calculate the ACR included 24-h to 96-h median lethal concentrations (LC50s) for acute tests, and 48-h to 54-d inhibition concentration (ICx) values for growth or reproduction for chronic exposures. Data from the present chronic toxicity tests, and other investigators, were used to propose a water quality guideline for long-term exposure to chloride using a species sensitivity distribution (SSD) approach. The 5th percentile from the SSD was calculated as 307 mg/L and proposed as the water quality guideline. Cladocerans were the most sensitive species in the dataset. Ceriodaphnia dubia was used to evaluate the relationship between water hardness and sensitivity to chloride. A strong relationship was observed and was used to establish a hardness-related equation to modify the proposed water quality guideline on the basis of water hardness, resulting in values ranging from 64 mg/L chloride at 10 mg/L hardness to 388 mg/L chloride at 160 mg/L hardness (as CaCO3). These data suggest that current water quality guidelines for chloride may be overly conservative in water with moderate-to-high hardness, and may not be sufficiently protective under soft-water conditions. © 2010 SETAC. Source

Martyniuk C.J.,University of New Brunswick | Alvarez S.,Donald Danforth Plant Science Center | Lo B.P.,Nautilus Environmental | Elphick J.R.,Nautilus Environmental | And 2 more authors.
Journal of Proteome Research | Year: 2012

Endocrine disruptors that act via the androgen receptor (AR) are less well studied than environmental estrogens, and there is evidence that treatment with AR agonists can result in masculinization of female fish. In this study, female fathead minnows (FHM) were exposed to the model nonaromatizable androgen 5-alpha dihydrotestosterone (DHT) (100 μg/L), the ureic-based herbicide linuron (LIN) (100 μg/L), and a mixture of DHT and LIN (100 μg/L each) to better characterize androgen action in females. LIN was used because of reports that this chemical has an antiandrogenic mode of action in fish. After 21d, DHT and LIN treatments resulted in a significant depression of plasma vitellogenin (Vtg) and DHT and DHT + LIN increased the prevalence of nuptial tubercles in female FHMs indicating masculinization. Using iTRAQ and an LTQ Orbitrap Velos, ∼2000 proteins were identified in the FHM liver and the number of proteins quantified after exposures was >1200. Proteins that significantly and consistently changed in abundance across biological replicates included prostaglandin E synthase 3, programmed cell death 4a, glutathione S transferases, canopy, selenoprotein U, and ribosomal proteins. Subnetwork enrichment analysis identified that interferon and epidermal growth factor signaling were regulated by DHT and LIN, suggesting that these signaling pathways are correlated to depressed plasma vitellogenin. These data provide novel insight into hepatic protein networks that are associated with the process of masculinization in teleosts. © 2012 American Chemical Society. Source

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