Acute and Chronic Toxicity of Nickel and Zinc to a Laboratory Cultured Mayfly (Neocloeon triangulifer) in Aqueous but Fed Exposures

Abstract

Aquatic insects are poorly represented in water quality criteria, and previous studies have suggested a lack of sensitivity in acute toxicity tests despite observational studies demonstrating the contrary. Our objectives were to determine the toxicity of nickel (Ni) and zinc (Zn) to the mayfly Neocloeon triangulifer in fed acute (96‐h) and chronic exposures to estimate aqueous effect concentrations while acknowledging the importance of dietary exposure for these insects. For the chronic tests, we conducted preliminary full–life cycle (~25–30 d) and subchronic (14 d) exposures to compare the relative sensitivity of the 2 test durations under similar conditions (i.e., feeding rates). Observing similar sensitivity, we settled on 14 d as the definitive test duration. Furthermore, we conducted experiments to determine how much food could be added to a given volume of water while minimally impacting dissolved metal recovery; a ratio of food dry mass to water volume (<0.005) achieved this. In the 14‐d tests, we obtained a median lethal concentration and most sensitive chronic endpoint of 147 and 23 µg/L dissolved Ni (acute to chronic ratio [ACR] = 6.4), respectively, and 81 (mean value) and 10 µg/L dissolved Zn (ACR = 8.1), respectively. The acute values are orders of magnitude lower than previously published values for mayflies, probably most importantly due to the presence of dietary exposure but also potentially with some influence of organism age and test temperature. Environ Toxicol Chem 2020;39:1196–1206. © 2020 SETAC

Bioaccumulation and Toxicity of Cadmium, Copper, Nickel, and Zinc and Their Mixtures to Aquatic Insect Communities

“…mayflies have been observed to be among the more tolerant of the generally metal‐sensitive mayflies (Clements 1994; Mebane et al 2015). Similar to the present study, the baetid mayfly Neocloeon triangulifer was the most chronically sensitive taxa to Zn in a sensitivity distribution of 35 taxa, although it was near to the middle of the sensitivity distribution for Ni (Soucek et al 2020; Figure 8). Life history characteristics likely contribute to Baetis persistence in streams (short life cycle, high propensity to drift), which could explain their quick recovery after pulse disturbances (Iwasaki et al 2018).…”

“…As noted, 10‐d exposures may be sufficient to produce sensitive results with Cu, which was also observed in the experimental stream studies by Leland et al (1989), which were reanalyzed by Brix et al (2011). Soucek et al (2020) obtained similar lowest‐effect levels for Ni and Zn when comparing full life cycle versus 14‐d subchronic tests, both initiated with <24‐h‐old larvae. In contrast, Clements (2004) found that 10‐d exposures to Zn or Cd+Zn mixtures produced few effects on the structure of insect communities, whereas we found marked reductions in overall taxa richness and the abundances of all mayfly taxa in similar concentration ranges but following approximately 30‐d exposures (Tables 1 and 2).…”

“…The SSD for Ni was updated with the 7 chronic invertebrate results reported by Besser et al (2011). The Ni and Zn SSDs were supplemented with baetid mayfly 14‐d subchronic test data reported by Soucek et al (2020). The Cd, Cu, and Zn EC20 values from the present study were adjusted to the same water types of the underlying SSDs.…”

Development of an Alternative Test System for Chronic Testing of Lotic Macroinvertebrate Species: A Case Study with the Insecticide Imidacloprid

“…A recently published paper by Almudi et al (2019) describes the establishment of a continuous culture system for the mayfly laboratory model Cloeon dipterum (Baetidae family) giving access to all development stages and providing high numbers of synchronized larvae for usage in chronic toxicity testing. In North America, larger progress has already been made in the field of development of culturing methods and test protocols for the mayfly larvae Neocleon triangulifer (Sibley et al 2020;Soucek and Dickinson 2015;Soucek et al 2020;Soucek et al 2018). Implication of study results…”

“…Although in North America suitable test and culturing methods are available for Neocloeon triangulifer and Hexagenia spp. (Soucek and Dickinson 2015;Struewing et al 2015;Soucek et al 2018Soucek et al , 2020, in Europe, progress was made in testing and culturing of Cloeon sp. (Almudi et al 2019).…”