Influence of feeding and organism age on the acute toxicity of sodium bromide to Artemia salina

Abstract

Bromide is a common ion found in freshwater and marine systems. Although normally at relatively low concentrations, higher levels may occur in point-released wastewaters as well as nonpoint runoff from agricultural or industrial locations where bromide compounds are used as biocides and disinfectants. In this study, the potential toxicity of NaBr in a saltwater environment was studied using the brine shrimp, Artemia salina. The confounding factors of organism age at test initiation and pre-test feeding were included in the test design. Survival of brine shrimp nauplii in several NaBr treatments up to 11,000 mg Br − /L (measured) was assessed after 24 h in both fed-and unfed-tests. In tests with unfed organisms, only the youngest (< 24 h old) nauplii had acceptable control survival (≥90%), while control survival for all of the tests with fed organisms (< 24 h old, < 48 h old, < 72 h old) was acceptable. There was also greater and more erratic mortality in the unfed tests. These data indicate feeding A. salina prior to initiating a short-term acute test improved performance. Not feeding the test organisms, especially in longer tests or when using > 24 h old organisms, may result in excessive control mortality and an invalid test. These studies show that, when healthy organisms are used in the toxicity tests, 11,000 mg/L of Br − (~ 14,200 mg/L NaBr) is not acutely toxic to Artemia salina.

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“…The impact of experimental conditions on toxicity assessment has been addressed in recent studies, primarily involving aquatic organisms (Lin et al 2021). The correlation between toxicity and environmental stimulus in the Artemia salina model has been reported in recent years (Asadi et al 2019;Pillard and Tapp, 2021). However, two critical variables for marine organisms have not yet been explored enough: circalunar variations and events from the agitation of the water.…”

“…In this study, these parameters were evaluated, using the hatching of Artemia salina cysts exposed to lead chloride as an experimental model. The EC10 obtained for PbCl 2 was chosen as a challenge to mimic concentrations usually found in contaminated natural environments (Pillard and Tapp, 2021).…”

“…One liter of distilled water and 30 g of sea salt were used for each experimental week, with constant stirring with a magnetic stirrer. Then, 50 mg of yeast (Saccharomyces cerevisiae) was added for every 10 ml of artificial seawater as food for newborn nauplii to avoid confounding starvation variables concerning toxicity (Pillard and Tapp, 2021).…”