A Mystery Tale: Nickel Is Fickle When Snails Fail—Investigating the Variability in Ni Toxicity to the Great Pond Snail

Abstract

Dissolved Ni concentrations inhibiting the growth of juvenile great pond snails (Lymnaea stagnalis) have been documented to vary from about 1 to 200 µg L −1 Ni. This variability makes L. stagnalis either a moderately sensitive or the most sensitive freshwater species to chronic Ni exposure tested to date. Given the role of sensitive species in environmental risk assessment frameworks, it is particularly important to understand this variability, i.e., to characterize the factors that modulate Ni toxicity and that may confound toxicity test outcomes when uncontrolled. In the present study, we tested if this variability was due to analytical (growth calculation: biomass versus growth rate), environmental (water quality), lab-specific practices, and/or snail population differences among earlier studies. Specifically, we reanalyzed previously published Ni toxicity data and conducted additional measurements of Ni aqueous speciation, short-term Ni uptake, and chronic Ni toxicity with test waters and snail cultures used in previous studies. Corrections for Ni bioavailability and growth calculations explained a large degree of variability in the published literature. However, a residual 16-fold difference remained puzzling between 2 studies: Niyogi et al. (2014) (low ECxs) and Cré mazy et al. (2018) (high ECxs). Indeed, differences in metal bioavailability due to water chemistry, lab-specific practices, and snail population sensitivity could not explain the large variation in Ni toxicity in these 2 very similar studies. Other potentially important toxicity-modifying factors were not directly evaluated in the present work: test duration, diet, snail holding conditions, and snail age at onset of testing. The present analysis highlights the need for further studies to elucidate 1) the mechanisms of growth inhibition in Ni-exposed L. stagnalis and 2) the important abiotic and biotic factors affecting this biological response. Until these processes are understood, substantial uncertainties will remain about inclusion of this species in Ni environmental risk assessment. Integr Environ Assess Manag 2020;16: 983-997.

Evaluation of Chronic Effects of Potassium Chloride and Nickel on Survival, Growth, and Reproduction of a Unionid Mussel (Lampsilis siliquoidea)

“…A similar conclusion was reached in previous NaCl toxicity tests with juvenile fatmucket at 20 °C and 23 °C, in which effect concentrations remained the same or slightly decreased (a difference within a factor of 2) when the exposure period was extended from 4 to 12 weeks (Wang, Kunz, et al, 2018). Crémazy et al (2020) investigated the high variability in chronic Ni toxicity to a mollusk (Great Pond snail, Lymnaea stagnalis) and found a 16-fold difference in 2-and 3-week EC20s obtained from two studies under similar test condition after Ni bioavailability correction using a Biotic Ligand Model (Niyogi et al, 2014;Crémazy et al, 2018). Compared with the snail data, the difference in the 4-week EC20s between the two Ni studies with mussels was smaller (41 µg Ni/L in Wang et al, 2020 and 91 µg Ni/L in the present study).…”

“…Crémazy et al (2020) investigated the high variability in chronic Ni toxicity to a mollusk (Great Pond snail, Lymnaea stagnalis ) and found a 16‐fold difference in 2‐ and 3‐week EC20s obtained from two studies under similar test condition after Ni bioavailability correction using a Biotic Ligand Model (Niyogi et al, 2014; Crémazy et al, 2018). Compared with the snail data, the difference in the 4‐week EC20s between the two Ni studies with mussels was smaller (41 µg Ni/L in Wang et al, 2020 and 91 µg Ni/L in the present study).…”

Updating the Chronic Freshwater Ecotoxicity Database and Biotic Ligand Model for Nickel for Regulatory Applications in Europe

“…Virtually all tests with L. stagnalis are juvenile growth tests and follow several different methods. The importance of other confounding factors influencing Ni sensitivity to L. stagnalis such as test duration, food sources, snail holding conditions, and snail age at test initiation has been suggested (Cremazy et al, 2020) and may account for at least some of the variability among these test results.…”

Empirical Bioavailability Corrections for Nickel in Freshwaters for Australia and New Zealand Water Quality Guideline Development

“…However, these poorly predicted studies included 3 tests with the sensitive species L. stagnalis (from a total of 6 tests) and 1 test for the relatively insensitive species C. tentans (from a total of 5 tests). There is uncertainty regarding the sensitivity of L. stagnalis to nickel (Cremazy et al 2020), and although all the data included in the present study were assessed for reliability this additional information has become available since the dataset was compiled. The predictions for aquatic plants with the invertebrate MLR (not shown) were less accurate than those calculated using the aquatic plants MLR.…”