Aquatic ecotoxicology approaches in Western Mexico

Abstract

A series of bioindicator organisms for aquatic ecosystems are being maintained under laboratory conditions in order to analyze effects of pollution on aquatic wildlife and potential effects on human health. Growth kinetics of algae Pseudokirchneriella subcapitata was used to evaluate effects of the surfactant nonilphenol (NP). Brachionus calyciflorus was used to set up a model of endocrine disruption using the fungicide vinclozolin (Vc). We exposed salamanders from the genus Ambystoma sp., to different concentrations of both the aneugen colchicine (COL) and the clastogen cyclophosphamide (CP) and we determined the frequency of micronucleated cells (MNC) in their shed skin. The presence of spontaneous micronuclei in peripheral blood erythrocytes from 10 fish species in Lake "La Alberca," Michoacan (Mexico), was evaluated as a possible biological indicator of genotoxic agents. Results confirm the sensivity of Pseudokirchneriella subcapitata to growth kinetics: the range of concentration of NP (20, 200 and 2000 microg L(- 1)) shows an inverted U shape in its maximum growth rate; Dimethyl sulfoxide (DMSO) used as a positive control and to solvate NP induced an inverse stimulatory effect on growth rate in the range of concentrations analyzed (0.0023, 0.023 and 0.23% v v(- 1)). In the use of the rotifer Brachionus calyciflorus, the range of Vc from 0.185 mg L(- 1) to 3 mg L(- 1) clearly showed an inverted U shape characteristic of endocrine disruptions. We were able to use shed skin from Ambystoma sp., to measure MNC frequencies induced either by an aneugenic or a clastogenic compound. The MNC frequency was increased significantly by all doses of COL and CP, administered either as single or repeated exposures. The presence of MNC in the shed skin and the speed of sloughing lead us to propose that the sheds of Ambystoma sp., or other amphibians that slough their skin, as suitable alternative models for detecting genotoxic exposures relevant to aquatic environments. In the survey to determine potential biological fish indicators for genotoxic agents, the frequency of spontaneous micronucleated erythrocytes (MNE) found in the goodeid Xenotoca melanosoma (3.7 +/- 1.6 MNC) and the cichlid Oreochromis aureus (2.0 +/- 1.0 MNC) suggests that these species can be considered as potential biological indicators.

Flurochloridone-based herbicides induced genotoxicity effects on Rhinella arenarum tadpoles (Anura: Bufonidae)

“…Whether the latter is true or not, the present results could confirm the importance of studying complete agrochemical formulations in toxicity screenings because the excipient(s) may have toxicological properties completely different from those of the active ingredients alone, and their impacts may be quite different, as demonstrated previously in different biotic matrices (Cox and Surgan, 2006;González et al, 2007;Nikoloff et al, 2012;Soloneski and Larramendy, 2010). The SCGE test has become extensively valuable as a biomarker in amphibians to monitor contaminated areas (in situ assay) (Burlibasa and Gavrila, 2011;Maselli et al, 2010;Ralph and Petras, 1998) as well as for screening xenobiotics after direct or indirect exposure (in vivo assay) (Binelli et al, 2009;Knakievicz et al, 2008;Mouchet et al, 2007;Zavala-Aguirre et al, 2007). We observed that, regardless of the concentration, acute exposure to Twin Pack Gold s or Rainbow s increased the frequency of primary DNA lesions estimated by alkaline SCGE, a result opposite that of the MN test.…”

Sublethal and lethal effects on Rhinella Arenarum (Anura, Bufonidae) tadpoles exerted by the pirimicarb-containing technical formulation insecticide Aficida®

“…Although, much higher toxicity has been reported for the aquatic microcrustacean D. magna (Kusk, 1996) as well as for the mosquito C. quinquefasciatus (Magnin et al, 1988), with an EC-50 of 0.014 mg L À1 and an LC-50 24 h of 8.5 mg L À1 , respectively. The MNi test has been extensively applied as an end-point for genotoxicity in amphibians (Wirz et al, 2005;Huang et al, 2007;Peltzer et al, 2008) to monitor contaminated areas (in situ assay) as well as for screening different compounds after direct or indirect exposure (in vivo assay) (Lajmanovich et al, 2005;Mouchet et al, 2007;Zavala-Aguirre et al, 2007;Binelli et al, 2008Binelli et al, , 2009Knakievicz et al, 2008). In 1986, Jaylet and coworkers (1986) described a model micronucleus test system using peripheral blood erythrocytes from the new larvae of Pleurodeles waltl for detecting mutagens in water pollution.…”

Micronuclei and Nuclear Buds Induced by Cyclophosphamide in Crocodylus moreletii as Useful Biomarkers in Aquatic Environments

“…Nonetheless, reliable and practical methods that detect the presence of genotoxic contaminants are scarce [ 4 ]. The micronucleus assay is commonly used for evaluating structural and numerical chromosomal aberrations caused by clastogenic and aneugenic agents [ 5 , 6 , 7 , 8 ], and it was originally developed in mammals [ 5 , 9 , 10 , 11 , 12 ]; however, it has been successfully adapted to other non-mammalian organisms, such as fish erythrocytes [ 13 ], amphibian larvae [ 14 , 15 ], and the shed skin of salamanders [ 16 ], among others.…”