Sulfate toxicity to early life stages of European whitefish (Coregonus lavaretus) in soft freshwater

Juha Karjalainen,Mikko Mäkinen,Anna K Karjalainen

doi:10.1016/j.ecoenv.2020.111763

Juha Karjalainen, Mikko Mäkinen + Show 1 more

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https://doi.org/10.1016/j.ecoenv.2020.111763

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Abstract

Sulfate occurs naturally in the aquatic environment but its elevated levels can be toxic to aquatic life in freshwater environments. We investigated the toxicity of sulfate in humic, soft freshwater to whitefish (Coregonus lavaretus) from fertilization of eggs to hatching i.e. during the critical phases of whitefish early development. Anadromous Kokemäenjoki whiteﬁsh eggs and sperm during fertilization, embryos and larvae were exposed in the long-term 175-day incubation to seven different sodium sulfate (Na2SO4) concentrations from 44 to 2 000 mg SO4 L−1. Endpoint variables were the fertilization success, offspring survival and larval growth. Egg fertilization and early embryonic development were the most sensitive developmental stages of whitefish to sulfate, although the fertilization success and survival of embryos decreased only in the highest concentration of 2 000 mg SO4 L−1. The survival during late embryonic period, hatching and the 5-day larval period was high and no difference between the control and sulfate treatments were observed. LC50-values of sulfate for early embryonic period and for the entire embryonic and larval period was 1 413 and 1 161 mg L−1, respectively. The NOEC (No-observed Effect Concentration) of sulfate for the both periods was 1 207 mg L−1. The tolerance of whitefish early stages to sulfate toxicity seems to be on the same level as the tolerance of other salmonids’ early stages.

Highlights

Sulfate (SO42, hereinafter SO4) is an anion, which occurs naturally in the aquatic environment
Sul fate levels typically are around 0.1–1% of the levels in the seas and from less than 1–6% of the levels in brackish waters, between 3 and 30 mg L− 1 (Environment Canada, 1984; Finnish Environment Institute, 2020; Katz, 1977; Sahlin and Ågerstrand, 2018)
Because the toxicity of sulfate is dependent on concentra tions of other major ions, with a general decrease in toxicity associated with an increase in water hardness (Elphick et al, 2011), the additional data of sulfate toxicity in soft waters are urgently needed to develop further the sulfate water quality guide lines (WQGs) for low water hardnesses (Elphick et al, 2011; Meays and Nordin, 2013; Sahlin and Ågerstrand, 2018)

Summary

Introduction

Sulfate (SO42-, hereinafter SO4) is an anion, which occurs naturally in the aquatic environment. The majority of sulfate toxicity studies have been acute exposures with aquatic invertebrates and have been con ducted in reconstituted deionized waters with varying compositions (Davies and Hall, 2007; Elphick et al, 2011; Lasier and Hardin, 2009; Mount et al, 1997; Soucek and Kennedy, 2005; USEPA, 2010), dech lorinated municipal tap waters (Elphick et al, 2011), well waters (Davies, 2007) or various combinations of these but not in natural soft freshwaters.

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