Use of fish farms to assess river contamination: Combining biomarker responses, active biomonitoring, and chemical analysis

• Published in: Aquatic toxicology 2013-09, Vol.140-141, p.439-448
• Main Authors: Quesada-García, Alba, Valdehita, Ana, Torrent, Fernando, Villarroel, Morris, Hernando, M. Dolores, Navas, José M.
• Format: Article
• Language: English
• Subjects: Active biomonitoring; Animals; BFCOD; Biomarkers; Biomarkers - analysis; chemical analysis; cities; Cytochrome P-450 CYP1A1 - metabolism; Environmental Monitoring - methods; Enzyme Activation - drug effects; enzyme activity; EROD; farming systems; fish farms; Fisheries; Fishes - metabolism; Fishes - physiology; freshwater fish; GC × GC–TOF–MS; Gene Expression Regulation - drug effects; Geologic Sediments - chemistry; mass spectrometry; messenger RNA; odors; Oncorhynchus mykiss; personal care products; pollutants; polycyclic aromatic hydrocarbons; rivers; Rivers - chemistry; sediments; Water Pollutants, Chemical - analysis; Water Pollutants, Chemical - toxicity
• ISSN: 0166-445X; 1879-1514
• DOI: 10.1016/j.aquatox.2013.07.007

•Trace levels of contaminants provoke long term toxic responses in fish.•Effects of trace levels of contaminants are evidenced by a combination of techniques.•Active biomonitoring, biomarkers and chemical analyses are complementary approaches.•An analytical strategy was developed for non-target screening of organic pollutants.•Fish farms can act as sentinels for detecting very low levels of contaminants. Here we addressed the possible effects of trace levels of contaminants on fish by means of a combination of biomarker responses, active biomonitoring (ABM), and chemical analysis. In environmental studies, cytochromes P4501A (Cyp1A) and Cyp3A and related enzyme activities (7-ethoxyresorufin-O-deethylase, EROD, and benzyloxy-4-[trifluoromethyl]-coumarin-O-debenzyloxylase, BFCOD, respectively) are commonly used as biomarkers for evidencing exposure to a variety of contaminants. In a rainbow trout (Oncorhynchus mykiss) fish farm that is routinely sampled to obtain references regarding normal levels of such enzyme activities in freshwater fish, we observed a strong and punctual increase in these activities at the end of 2011. In order to shed light on the causes of this induction, we transferred some fish to a fish farm with controlled conditions and examined them using an active biomonitoring (ABM) approach. EROD activity showed a decrease of 80% from the original values after 7 days in the control farm, while BFCOD activity was also reduced after 15 days. Although not significant, a decrease in cyp1A and cyp3A mRNA levels was also observed. To determine the presence of pollutants, water and sediment samples from the river feeding the fish farm were analyzed by two-dimensional gas chromatography–time-of-flight mass spectrometry (GC×GC–TOF–MS). The screening study reflected a weak inflow of pollutants in the monitored area, which is located far from any industrial activity or densely populated cities. Trace levels of polyaromatic hydrocarbons (PAHs) and personal care products (the polycyclic musk fragrance HHCB, and triclosan) were detected in sediments, at concentrations ranging from 0.01 to 38ng/g dry weight, and in water from 4 to 441ng/L. The approach followed in this study proved useful as a biomonitoring technique for the early detection of trace contaminants.