title: Biochemical responses in the gills of Meretrix meretrix after exposure to treated municipal effluent.
abstract: The biochemical effects in marine bivalves exposed to increasing concentrations of treated municipal effluent (TME), as discharged into receiving marine waters, are investigated. The effluent was collected from a municipal sewage treatment plant (STP) in Qingdao (China). Meretrix meretrix were exposed to effluent volume ratio (EVR, ratio of effluent volume accounted for tailwater seawater mixture) 0%, 1%, 5%, 10%, and 20% (v/v) TME for 15 days and the following biochemical responses in gills were measured: (1) the activity of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), and glutathione (GSH) content, and lipid peroxidation levels of malondialdehyde (MDA), as oxidative stress biomarkers; (2) the activity of 7-ethoxyresorufin O-deethylase (EROD) and gluthathione S-transferase (GST), as phase I and phase II conjugation enzymes, respectively; (3) acetylcholinesterase (AChE), as a biomarker of neurotoxicity, and (4) metallothioneins (MTs), as proteins strongly induced by heavy metals. Most of the biochemical indices present high and significant variation frequency (above 50%). There is enhancement in the antioxidant enzymes, EROD, GST, AChE, and MTs, as well as consumption of GSH. The current experimental results suggest that effluent with concentrations less than 20% (v/v) do not cause lipid peroxidation damage. This implies that the activated defense is sufficient to protect the bivalves' gill tissues from cytotoxicity produced by the effluent. Furthermore, GSH, GPx, MTs, and GR are suitable, and sufficiently sensitive, biomarkers to indicate the pollution levels in marine environments receiving such effluent.
authors.affiliation: Key Laboratory for Marine Environment and Ecology of Ministry of Education, Ocean University of China, Qingdao, Shandong Province 266100, China.
authors.forename: Ru
authors.initials: R
authors.lastname: Wan
authors.affiliation: Key Laboratory for Marine Environment and Ecology of Ministry of Education, Ocean University of China, Qingdao, Shandong Province 266100, China.
authors.forename: Fanping
authors.initials: F
authors.lastname: Meng
authors.affiliation: Key Laboratory for Marine Environment and Ecology of Ministry of Education, Ocean University of China, Qingdao, Shandong Province 266100, China.
authors.forename: Wenchao
authors.initials: W
authors.lastname: Fu
authors.affiliation: Key Laboratory for Marine Environment and Ecology of Ministry of Education, Ocean University of China, Qingdao, Shandong Province 266100, China.
authors.forename: Qun
authors.initials: Q
authors.lastname: Wang
authors.affiliation: Key Laboratory for Marine Environment and Ecology of Ministry of Education, Ocean University of China, Qingdao, Shandong Province 266100, China.
authors.forename: Enping
authors.initials: E
authors.lastname: Su
mesh_terms: D000110:Acetylcholinesterase / Q000378:metabolism; D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D015415:Biomarkers / Q000378:metabolism; D049872:Bivalvia / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D002374:Catalase / Q000378:metabolism; D019363:Cytochrome P-450 CYP1A1 / Q000378:metabolism; D005880:Gills / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism; D005979:Glutathione Peroxidase / Q000378:metabolism; D005980:Glutathione Reductase / Q000378:metabolism; D005982:Glutathione Transferase / Q000378:metabolism; D015227:Lipid Peroxidation / Q000187:drug effects; D008668:Metallothionein / Q000378:metabolism; D018384:Oxidative Stress; D012623:Seawater; D013482:Superoxide Dismutase / Q000378:metabolism; D014865:Waste Disposal, Fluid; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D000975:Antioxidants; D015415:Biomarkers; D014874:Water Pollutants, Chemical; D008668:Metallothionein; D002374:Catalase; D005979:Glutathione Peroxidase; D019363:Cytochrome P-450 CYP1A1; D013482:Superoxide Dismutase; D005980:Glutathione Reductase; D005982:Glutathione Transferase; D000110:Acetylcholinesterase; D005978:Glutathione
keywords: Effluent; Marine bivalve; Oxidative stress; Sewage treatment plant