Influence of heavy metals on physiological and biochemical parameters of Pseudorasbora parva (Cypriniformes, Cyprinidae)

Damage on DNA and hematological parameters of two bat species due to heavy metal exposure in a nickel-mining area in central Brazil

Exposure to heavy metals in mining zones is a significant threat, which can affect ecosystem services and contribute to the decline of wild bat populations. The present study investigated the impacts caused by mining on two bat species in central Brazil, the nectarivorous Glossophaga soricina and the frugivorous Carollia perspicillata. The bats were collected from a nickel-mining zone (treatment) and a protected area (control). The leukocyte profile of each species was compiled and genotoxicity (comet assay) and mutagenicity (micronucleus test) were determined using the appropriate procedures. Glossophaga soricina presented significantly higher frequencies of eosinophils and monocytes in the mining zone in comparison with the protected area, whereas C. perspicillata presented higher frequencies of lymphocytes in the mining zone, but significantly lower frequencies of monocytes. Concomitantly, G. soricina also presented a higher frequency of DNA damage, although no variation was found in this parameter in C. perspicillata when comparing environments. We also found no significant differences between populations in terms of the frequency of micronuclei and other nuclear abnormalities. Overall, the results of the study indicate that bats are susceptible to immunological disorders and DNA damage in mining zones, with the nectarivorous G. soricina appearing to be relatively more susceptible and thus a potentially effective bioindicator of the impact of contamination in these environments.

Urbanity as a source of genotoxicity in the synanthropic Kelp Gull (Larus dominicanus)

Increases in human population lead to an increase in urban wastes, which could affect wildlife in several ways. Urban pollutants can affect erythrocytes of birds generating morphological membrane and nuclear anomalies. The Kelp Gull (Larus dominicanus) is an opportunistic species, which take advantage of urban environments, thus being highly exposed to environmental pollution. In northeastern Patagonia, the dynamic of the waste management was transformed in the last decade and consequently, gulls changed their movements in response to changes in waste management systems. The food available to the seagulls went from being a mixture of urban/fishing discards until 2015, when this landfill closures, to being domestic urban offerings. In order of evaluating genotoxicity and changes in pollutants exposition due to these changes, we analyzed the frequencies of erythrocytes nuclear abnormalities and micronuclei (ENAs and MN respectively) in 58 blood smears from adults extracted during the non-breeding season in two periods in landfills with different waste compositions: a mixed landfill (ML) in 2013 before closure (n = 24) versus an urban landfill (UL) (n = 34) in 2021. We found that the Kelp Gull showed high values of abnormalities with an average of 151.5 /10,000 RBC in comparison with other seabird species. The bud and notched types of ENAs were the most prevalent abnormalities in both sites. We did not find significate differences in the overall abnormality frequency between sites, however we found significant higher frequencies in displaced and tailed types of ENAs in ML. We also found poikilocytosis, as seen previously in other animals exposed experimentally to pollutants such as metals and crude oil. Cellular abnormalities found in the Kelp Gull suggest an exposition of individuals to pollutants in foraging areas. The hemispheric distribution and the synanthropic characteristics of the species denote its importance as a suitable global monitor of genotoxicity.