Effects of pulse duration and post-exposure period on the nitrite toxicity to a freshwater amphipod.
This research assesses the effects of nitrite pulses and post-exposure periods after nitrite exposures on the survival of the freshwater amphipod Eulimnogammarus toletanus. A toxicity bioassay was performed using three different nitrite concentrations (0.5, 5.0 and 10.0 mg/L NO(2)-N), four pulse exposures (1, 8, 24 and 48 h) for each nitrite concentration, and four post-exposure times until to complete 96 h (i.e., 95, 88, 72 and 48 h, respectively). Our results showed a significant effect of nitrite concentrations, pulses and post-exposure times on the mortality of E. toletanus. The cumulative mortality at the end of pulse and that at the end of post-exposure time (delayed mortality) were different. We conclude that due to the high frequency of intermittent pollution in aquatic ecosystems it is necessary to incorporate the post-exposure effects into the traditional toxicological parameters to achieve a more realistic assessment of toxicants, especially at very short-term exposures.
Alonso
Alvaro
A
Department of Ecology, Faculty of Biology, University of Alcalá, 28871 Alcalá de Henares, Madrid, Spain. aafernandez1976@yahoo.es
Camargo
Julio A
JA
D033304:Amphipoda / Q000187:drug effects* / Q000254:growth & development; D000818:Animals; D004784:Environmental Monitoring / Q000379:methods*; D005618:Fresh Water / Q000032:analysis*; D009573:Nitrites / Q000633:toxicity*; D013030:Spain; D013997:Time Factors; D018675:Toxicity Tests / Q000379:methods; D014874:Water Pollutants, Chemical / Q000633:toxicity*
D009573:Nitrites; D014874:Water Pollutants, Chemical