Effects of low arsenic concentration exposure on freshwater fish in the presence of fluvial biofilms

Baigal-Amar Tuulaikhuu; Berta Bonet; Helena Guasch

doi:10.1016/j.scitotenv.2015.11.126

Effects of low arsenic concentration exposure on freshwater fish in the presence of fluvial biofilms

Sci Total Environ. 2016 Feb 15:544:467-75. doi: 10.1016/j.scitotenv.2015.11.126. Epub 2015 Dec 4.

Authors

Baigal-Amar Tuulaikhuu¹, Berta Bonet², Helena Guasch³

Affiliations

¹ Institute of Aquatic Ecology, Department of Environmental Sciences, University of Girona, Spain; Department of Ecology, School of Agroecology, Mongolian University of Life Sciences. Electronic address: baigal.tuulaikhuu@udg.edu.
² Institute of Aquatic Ecology, Department of Environmental Sciences, University of Girona, Spain.
³ Institute of Aquatic Ecology, Department of Environmental Sciences, University of Girona, Spain. Electronic address: helena.guasch@udg.edu.

PMID: 26657392
DOI: 10.1016/j.scitotenv.2015.11.126

Abstract

Arsenic (As) is a highly toxic element and its carcinogenic effect on living organisms is well known. However, predicting real effects in the environment requires an ecological approach since toxicity is influenced by many environmental and biological factors. The purpose of this paper was to evaluate if environmentally-realistic arsenic exposure causes toxicity to fish. An experiment with four different treatments (control (C), biofilm (B), arsenic (+As) and biofilm with arsenic (B+As)) was conducted and each one included sediment to enhance environmental realism, allowing the testing of the interactive effects of biofilm and arsenic on the toxicity to fish. Average arsenic exposure to Eastern mosquitofish (Gambusia holbrooki) was 40.5 ± 7.5 μg/L for +As treatment and 34.4 ± 1.4 μg/L for B+As treatment for 56 days. Fish were affected directly and indirectly by this low arsenic concentration since exposure did not only affect fish but also the function of periphytic biofilms. Arsenic effects on the superoxide dismutase (SOD) and glutathione reductase (GR) activities in the liver of mosquitofish were ameliorated in the presence of biofilms at the beginning of exposure (day 9). Moreover, fish weight gaining was only affected in the treatment without biofilm. After longer exposure (56 days), effects of exposure were clearly seen. Fish showed a marked increase in the catalase (CAT) activity in the liver but the interactive influence of biofilms was not further observed since the arsenic-affected biofilm had lost its role in water purification. Our results highlight the interest and application of incorporating some of the complexity of natural systems in ecotoxicology and support the use of criterion continuous concentration (CCC) for arsenic lower than 150 μg/L and closer to the water quality criteria to protect aquatic life recommended by the Canadian government which is 5 μg As/L.

Keywords: Antioxidant enzyme activity; Arsenic; Biofilm; Ecological realism; Mosquitofish.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Animals
Arsenic / toxicity*
Biofilms*
Catalase / metabolism
Environmental Exposure
Fishes / physiology*
Oxidative Stress
Superoxide Dismutase / metabolism
Water Pollutants, Chemical / toxicity*

Substances

Water Pollutants, Chemical
Catalase
Superoxide Dismutase
Arsenic