Why are Early Life Stages of Aquatic Organisms more Sensitive to Toxicants than Adults?

Abstract

Additional information is available at the end of the chapter http://dx.doi.org/10.5772/55187 . Introduction . . The selection of a suitable test speciesToxicity tests are designed to determine the specific concentrations of chemicals that induce a measured effect on a target organism. However, the potency of any toxicant can be influenced by the characteristics of the chemical, as well as environmental temperature, ph, water chemistry, salinity and species life stage, sensitivity, pre-exposure specific factors. Environmental factors can either modify the toxicant itself or the immediate environment of an organism, increasing or decreasing the effects of the toxicants. Species specific factors can alter the organism/toxicant interaction by modifying the rate of uptake, distribution, elimination and detoxification pathways. Therefore when conducting toxicity tests, it is important to have controlled environmental conditions and select suitable test species to ensure reliable, relevant, reproducible, defensible and ecologically significant results. The selection of a suitable test species can be based on several criteria• the species should be widely available• they should be easily maintained under laboratory conditions and provide sufficient numbers of an appropriate size and age• the genetics, genetic composition and history of the organisms should be known• they should the most sensitive species in the environment.

Parental stressor exposure simultaneously conveys both adaptive and maladaptive larval phenotypes through epigenetic inheritance in the zebrafish (Danio rerio)

“…Crude oil exposures were made on early F 1 larvae from hatching to 5 dpf ( Fig. 1), which are among the most sensitive developmental stages (Mager et al, 2017;McKim, 1977;Mohammed, 2013;Réalis-Doyelle et al, 2016;Woltering, 1984). Zebrafish embryos and early larvae subsist on yolk absorbance during the first 5-6 dpf (Anderson et al, 2011;Kimmel et al, 1995), which prevented us from using dietary crude oil exposure as for the P 0 parents.…”

Effects of low, subchronic exposure of 2,4‐Dichlorophenoxyacetic acid (2,4‐D) and commercial 2,4‐D formulations on early life stages of fathead minnows (Pimephales promelas)

“…Early developing stages in aquatic organisms are typically at higher risk from toxicants than their adult counterparts (Lotufo and Fleeger 1997;M acov a et al 2008;Fairchild et al 2009;Mensah et al 2011). Although early developmental stages often represent a more susceptible period for toxicant exposure (Laale and Lerner 1981;Von Westernhagen 1988;McKim 1995;Bentivegna and Piatkowski 1998;Oikari et al 2002;Mohammed 2013), most studies on the effects of fish exposed to 2,4-D used either adult or juvenile life stages. To accurately predict the effect of 2,4-D herbicides, it is crucial to explore their impacts on the survival and development of fishes, especially during early development (embryo and larva stages), to understand their total impact.…”

Impact of dispersant on early life stages of the water flea Daphnia magna and the eastern oyster Crassostrea virginica

“…Also, the oily (hydrophobic) nature of daphnid antennae and carapace likely adsorbed HPEI (Gerritsen & Porter, 1982;Bozich et al, 2014). properly detoxify or sequester them (Mohammed, 2013). A pivotal life transition from larvae to spat, equivalent to the present study's 0.3-mm size, occurs when the oysters are using their energy to grow their shell by feeding and secreting calcium carbonate (Kennedy et al, 1996).…”

“…The increased susceptibility of the Easter oyster to Corexit 9500 induced toxicity is likely as a result of its life stage. During oyster early life stages, the organisms filter in toxicants but have immature detoxification pathways and cannot properly detoxify or sequester them (Mohammed, ). A pivotal life transition from larvae to spat, equivalent to the present study's 0.3‐mm size, occurs when the oysters are using their energy to grow their shell by feeding and secreting calcium carbonate (Kennedy et al, ).…”