Effect of Total Dissolved Solids on Fertilization and Development of Two Salmonid Species

Abstract

Some studies have shown that the early life stages of salmonids are particularly sensitive to elevated concentrations of total dissolved solids (TDS). We evaluated the effect of TDS released in treated effluent into Snap Lake (Northwest Territories, Canada) by the Snap Lake Diamond Mine on two salmonids native to Snap Lake: Salvenius namaycush (lake trout) and Thymallus arcticus (Arctic grayling). Exposures encompassed the embryo-alevin-fry early life stages and extended to 142 days for lake trout and 69 days for Arctic grayling. Such extended testing is uncommon with these two species. Two exposures were conducted with each species, one initiated prior to fertilization, and the other subsequent to fertilization. Fertilization, survival, and growth were not adversely affected for either species by TDS at concentrations >1400 mg/L, with the exception of survival of lake trout, which produced an LC20 of 991 mg/L in one test, and >1484 mg/L in the second test. For the specific TDS composition tested, which was dominated by chloride (45 %-47 %) and calcium (20 %-21 %), the early life stages of these two fish species were relatively insensitive. Although some authors have suggested lower TDS regulatory limits for salmonid early life stages, our study indicates that this is not necessary, at least for these two fish species and for the specific ionic composition tested.

Effects of Maternally Transferred Egg Selenium on Embryo‐Larval Survival, Growth, and Development in Arctic Grayling (Thymallus arcticus)

“…The study design involved assessing larval deformities once fish reached the swim‐up stage, which coincides with the onset of feeding. Arctic grayling reach swim‐up approximately 5 d following hatch (Baker et al 2015). Consequently, for fish from Fish Creek, which were tested first, hatched fish were removed from each replicate every 2 to 3 d once swim‐up began and assessed for deformities.…”

Development of a total dissolved solids (TDS) chronic effects benchmark for a northern Canadian lake

“…All point estimates are presented as calculated TDS concentrations. Additional details are provided in Golder (); Chapman (, , ); Baker et al (); Marus et al (); and Chapman and Elphick (). Control performance met test acceptability criteria for all test methods, and test results were corrected for mean control responses.…”

“…The following tests were conducted. A brief summary of methodology is provided below; full details on methodology are provided in Golder (); Chapman (, , ); Baker et al (); Marus et al (); and, Chapman and Elphick (). Phytoplankton: 72‐h growth inhibition of the green alga Pseudokirchneriella subcapitata (Environment Canada ) and 120‐h growth inhibition of the diatom Navicula pelliculosa (ASTM ).…”

“…Three‐brood survival and reproduction testing (Environment Canada ) with a second daphnid species, not found in Snap Lake, Ceriodaphnia dubia , resulted in highly variable results that were not useful for determining the TDS benchmark (Chapman ). Benthic Invertebrates: 10‐d survival and growth of chironomid larvae ( Chironomus dilutus ; Environment Canada ). The genus Chironomus is found in Snap Lake. Fish: Early life stage (ELS) tests with Lake Trout ( Salvelinus namaycush ; a fall spawner) and Arctic Grayling ( Thymallus arcticus ; a spring spawner) following procedures based on Environment Canada () to assess potential effects on embryo, alevin, and fry development of each species (Golder ; Baker et al ). A 32‐d ELS test with fathead minnow ( Pimephales promelas ) was performed to assess potential effects on hatching of fertilized eggs, survival, and growth (USEPA ).…”

“…Site‐specific aquatic toxicity tests using a TDS mixture representative of Snap Lake conditions were conducted including novel tests (Baker et al ; Marus et al ). Based on these tests, a site‐specific benchmark, based on chronic effects, was developed for TDS and its major constituent ions in Snap Lake.…”