Effect of zinc on four populations and two generations of Gammarus pulex (L.)

Abstract

SUMMARY 1. The amphipod Gammarus pulex (L.) is increasingly used in toxicity assessments and is usually obtained from wild populations. Interpopulation variability in response to toxicants may be due to genetic or phenotypic differences and could be large in wild‐caught organisms exposed to different environmental conditions. This paper describes an investigation designed to assess the extent of lethal and sublethal variability between four different G. pulex populations when exposed to zinc, and to determine whether differences observed in the parental generation were also apparent in offspring bred in the laboratory. 2. The mortality of G. pulex from one of the four field‐caught populations (Crags Stream) was significantly lower than for animals from the other three populations for the first 2 days of exposure. After 6 days’ exposure the LC50 values for all four populations did not differ significantly, and were approximately 1.0 mg Zn 1‐−1. Sublethal effects on feeding rate after 6 days’ exposure were also similar for all four populations (feeding rate EC50 approximately 0.5 mg Zn 1‐−1). 3. Lethal effects on the F1 generation were similar among the four populations, in contrast to the short‐term differences observed in the parental generation. These results suggest that interpopulation differences in zinc tolerance in G. pulex are short‐lived, and phenotypically rather than genetically based.

Evaluation of sensitivity and specificity of two crustacean biochemical biomarkers

“…To our knowledge, no previous studies have focused on the effect of LAS, permethrin, or pirimiphos‐methyl on the Gammarus sp. feeding rate, but the zinc results are similar to those previously reported [17,35].…”

“…However, the rank order of chemical toxicities observed in this study agrees well with previously published data for G. pulex. Reported 96‐h LC50 values are 5.9 to 34 μg/L for lindane [33,34], 1.0 to 1.9 mg/L for zinc [35], and 3.1 to 3.4 mg/L for LAS [36]. Results from studies regarding median survival times of G. pulex on exposure to permethrin suggest a 96‐h LC50 of less than 1 μg/L [37].…”

“…Effects on ChE activity were only observed at exposure to pirimiphos‐methyl, with significant inhibition of enzyme activity occurring after 24‐h exposure to 1.9 μg/L or 48‐h exposure to 0.77 μg/L. Significant reductions in G. pulex ChE activity have been observed after 24‐h exposure to fenitrothion at 1 μg/L, parathion at 1 μg/L, and malathion at 0.1 μg/L [35,43]. In addition, Day and Scott [44] reported that 24‐h exposure to azinphosmethyl at 20 μg/L significantly inhibited ChE activity in the amphipod Hyallela azteca.…”

Evaluation of the Gammarus Pulex in Situ Feeding Assay as a Biomonitor of Water Quality: Robustness, Responsiveness, and Relevance

“…Feeding inhibition is a general stress response exhibited by a variety of organisms [11], and G. pulex feeding rate is inhibited by a wide range of stressors [14][15][16][17][18][19][20][21][22]. Feeding inhibition can be measured in situ, and hence this assay has been proposed as an in situ indicator of water quality [15].…”

Evaluation of the Gammarus pulex in situ feeding assay as a biomonitor of water quality: Robustness, responsiveness, and relevance

“…However, the feeding rate of G. pulex is affected by many intrinsic and extrinsic factors. Intrinsic factors include parasite load [23], source population [17,18], and body size [24]. Extrinsic factors include temperature [25], dissolved oxygen concentration [25], and pH [26].…”