Sublethal effects of atrazine on embryo-larval development of Rhinella arenarum (Anura: Bufonidae)

Abstract

Atrazine (ATR), one of the most widely used herbicides in the world, affects not only target organisms but also the biota in general. Here, the teratogenic and neurotoxic effects of ATR on Rhinella arenarum (South American toad) embryos, and larvae were evaluated by means of standardized bioassays during acute and chronic exposures. The herbicide had a significant incidence of malformations, with a Teratogenic Index (TI) of 3.28. The main effects were delayed development, reduced body size, microcephaly, axial flexures, wavy tail and edema. In addition, delayed development, reduced development of forelimbs, and edema were recorded at metamorphosis stages. Scanning electron microscopy allowed observing different degrees of cellular dissociation and persistent cilliar cells in specific regions like the adhesive structure and tail fin. Results obtained by ATR 24 h pulse exposures at six developmental stages pointed out blastula as the most susceptible developmental stage both for immediate and delayed adverse effects. A noteworthy recovery capacity from acute toxic effects was recorded from the neural plate stage onwards. Regarding neurotoxic effects, abnormal, and erratic swimming and spasmodic contractions were recorded. Both the teratogenic and neurotoxic effects reported in this study demonstrate the importance of evaluating sublethal effects in non-target organisms as they could imply reduced fitness of individuals and eventually a population decline. The Hazard Quotients (HQ) for ATR ranged from 0.14 to 10.80, and the fact that some of these values are above USEPA's level of concern indicate that ATR is likely a risk to R. arenarum.

Survival and cholinesterase activity of Asian common toad (Duttaphrynus melanostictus) tadpoles following short term exposure to a carbosulfan-based pesticide

“…It is likely that pesticide exposed tadpoles are at a disadvantage under natural conditions and may face threats and indirect mortality as a consequence of delayed development. Delayed development and metamorphosis due to exposure to other pesticides have also been reported earlier for D. melanostiscus (Jayawardena et al 2011;Wijesinghe et al 2011) and other amphibian species (Svartz et al 2012;Saka et al 2013). Among other factors, increased energetic costs involved in abnormal behaviour could have led to prolong developmental period of these tadpoles.…”

Effect of salicylic acid on early life stages of common carp (Cyprinus carpio)

“…The influence of salicylic acid on FCF was also significant (p < 0.05) in all salicylic acid exposed groups. It is well known that early life stages of fish are generally regarded as the most sensitive to toxic agents (Hutchington et al, 1998;Wiegand et al, 2001;Hostovsky et al, 2012;Svartz et al, 2012). Zivna et al (2013) found increased body weight in groups exposed to 120 and 250 mg/l of acetylsalicylic acid.…”

“…Early life stages of fish are generally regarded as the most sensitive to toxic agents (Hutchington et al, 1998;Wiegand et al, 2001;Hostovsky et al, 2012;Svartz et al, 2012) and are ideal models for determining responses to environmental contaminants.…”

Toxicological aspects of photocatalytic degradation of selected xenobiotics with nano-sized Mn-doped TiO2

“…ATZ is one of the important environmental pollutants, especially for surface waters (De Geronimo et al, 2014), but the solubility of ATZ is low and it did not cause high mortality on aquatic organisms (Lenkowski et al, 2010;Svartz et al, 2012;Chromcova et al, 2013). So, the LC 50 of ATZ could not be obtained up to 200 mg/L exposure in embryos or tadpoles of X. laevis.…”