Natural tissue concentrations in adultAmbystoma maculatumand larval DNA damage from exposure to arsenic and chromium

Abstract

Arsenic (As) and chromium (Cr) are two contaminants that are detected in aquatic and terrestrial habitats. Using the spotted salamander, Ambystoma maculatum, to assess impacts from these contaminants may be advantageous as adults live and breed in such environments. Adult amphibians typically exhibit elevated tissue concentrations of contaminants present in their environment, while larval stages were found to exhibit increased sensitivity to pollutants. From January through March of 2015, during the spring breeding season, 5 adults and approximately 32 egg masses were collected from a local breeding site. Field levels of As and Cr ranged from 5.99 to 8.88 µg/L and 1.45 to 2 µg/L, respectively, while mean adult As tissue concentrations were 56.74 µg/g dry weight for heart, 0.92 µg/g for liver, and 1.21 µg/g for tail tissue. Mean tissue concentrations for Cr were 87.64 µg/g for heart, 1.47 µg/g for liver, and 6.92 µg/g for tail. Developing larvae that were collected from the field and exposed in a lab setting for 12 d to 0.2 or 20 mg/L of either As or Cr displayed little DNA damage attributed to As, but marked damage due to exposure to 20 mg/L Cr when assessed using the comet assay. Exposure to a mixture of either 0.25:0.1 or 25:10 mg/L As and Cr resulted in significant DNA damage at the lower concentration of 0.25:0.1 mg/L. As adult spotted salamanders were found to possess high concentrations of these contaminants in cardiac tissue, and larvae were shown to be susceptible to DNA damage from increased exposures, assessing impacts and potential declines of amphibian populations exposed to As and Cr is needed.

Perspectives of Genetic Damage and Epigenetic Alterations by Hexavalent Chromium: Time Evolution Based on a Bibliometric Analysis

“…Researchers consistently report Cr­(VI) induces genetic damage in a dose- and time-dependent manner. Notably, Gardner et al showed exposure to a mixture of Arsenic (As) and Cr resulted in significant DNA damage even at the low concentration of 0.25:0.1 mg/L, implying a synergistic effect of polymetallic exposure …”

“…Notably, Gardner et al showed exposure to a mixture of Arsenic (As) and Cr resulted in significant DNA damage even at the low concentration of 0.25:0.1 mg/L, implying a synergistic effect of polymetallic exposure. 27 More cell culture studies were performed than studies focused on human beings, animals, or plants (Table3). Almost all cell culture experiments reported both particulate [like zinc chromate (ZnCrO 4 ), barium chromate (BaCrO 4 ), and lead chromate (PbCrO 4 )] and soluble Cr(VI) [like sodium chromate (Na 2 CrO 4 ), potassium chromate (K 2 CrO 4 ), sodium dichromate (Na 2 Cr 2 O 7 ), and potassium chromate (K 2 Cr 2 O 7 )] induced genetic damage in cells derived from different species.…”

Histone demethylase JHDM2A participates in the repair of arsenic-induced DNA damage in L-02 cells by regulating DDB2

“…Abnormal DNA damage repair is one of the mechanisms of liver injury caused by arsenic poisoning, and arsenic can interfere with the cellular DNA damage repair process and cause chromosomal DNA damage (Gardner et al, 2018). DNA damage binding protein (DDB2), a product of the pigmentation Group E gene, recognizes DNA damage sites and is one of the important initiation genes of the nucleotide excision repair pathway (NER) in DNA damage repair (Ribeiro-Silva et al, 2020).…”