Fish as bioindicators of brackish ecosystem health: integrating biomarker responses and target pollutant concentrations

Abstract

Biological responses and contaminant levels in biological tissues were investigated in fish specimens of grass goby (Zosterisessor ophiocephalus) collected in spring 2000 in a moderately polluted brackish ecosystem, the Orbetello lagoon (southern coast of Tuscany, Italy). The complexity of harmful effects that contaminants may cause in fish over time was assessed. General condition indices (somatic liver index, and gonadal somatic index), cytochrome P450 enzymes, acetylcholinesterase activity and ovarian morphology were integrated with the content of organochlorines (OCs-hexachlorobenzene, DDTs and polychlorinated biphenyls) in liver and ovaries and p-nonylphenol (NP) and lower ethoxylate (NPE 1-2) content in muscle and ovaries as well. Samples collected from the western basin of the lagoon near the Orbetello sewage treatment plant had somatic liver index values and two P450 activities significantly higher than those collected from the same basin at the Albegna river delta and in the Ansedonia canal in the eastern basin (P < 0.05). On the other hand, while muscle content of p-NP and NPE 1-2 was significantly higher in samples from the Orbetello and Albegna river sites than in samples from the Ansedonia canal site, OC levels in liver (DDTs > PCBs > HCB) were particularly lower in samples from STP compared to levels detected in sites AC and AR. Light microscopy of ovaries revealed that although the gonads were sexually mature, the diameter of the oocytes and eggs was smaller than that commonly reported. High levels of OCs and NPs were, in fact, observed in grass goby ovaries, and the differences observed between acetylcholinesterase activities among investigated sites suggest exposure to insecticides as well. The integration of biological responses and contaminant tissue content reveals that certain areas of the lagoon are selectively impacted by various human activities and helps in distinguishing relationships between biological responses and contaminant load in the lagoon environment.

Classifying Ecological Quality and Integrity of Estuaries

“…Ethoxyresoufin O-deethylase (EROD) enzyme activity is widely used to detect exposure to PCBs and PAHs. The inhibition of acetylcholinesterase (AchE) enzyme activity also represents a specific marker of exposure to agricultural pesticides such as organophosphate and carbamate insecticides (Corsi et al, 2003;Lam and Gray, 2003;Vasseur and Cossu-Leguille, 2003). Other cellular-level biomarkers may also include parts of cells confined to certain tissues, or nucleic acids or specific regions of protein within nerve synapses or cell membranes (Lam and Gray, 2003).…”

“…Although cellular-level biomarkers can serve as early warning systems for exposure to and/or toxicity of certain compounds, several biomarkers are also influenced by other factors such as hormones, growth factors, reproductive stage, and stress as well as other chemical compounds; they can also be tissue-and species-dependent (Vasseur and CossuLeguille, 2003). The influence of season, sex, age, reproductive stage, and environmental conditions therefore must be known for these tools to be effective for environmental monitoring (Corsi et al, 2003;Vasseur and Cossu-Leguille, 2003;Sánchez and Porcher, 2009). …”

“…In fish, the liver is the main storage organ and is also the site of detoxification . If the stress persists or if the detoxifying mechanisms fail, then this can result in cell damage and physiological changes (Corsi et al, 2003;Vasseur and Cossu-Leguille, 2003). Fish liver structure or histopathology can provide a good indication of exposure to xenobiotics, and can also indi cate the ability of an individual to resist future insults (Stentiford et al, 2003).…”

“…The gona dosomatic index (GSI) compares the mass of the gonad with the total mass of the animal and assumes that an ovary increases in size with increasing development; the liver somatic index (LSI) relates liver weight to whole body weight and can also provide an indication of the health of an 2011, Vol. , DOI: 10.1016/B978-0-12-374711-2.00 1 10 Treatise on Estuarine and Coastal Science, 162, 9-1 125-individual; if an organism is not feeding, then liver weight will decrease Corsi et al, 2003). Any effect by contaminants or stress on the integrity of the gonads and/or liver will affect the GSI and LSI.…”

Assessment of ecosystem health during the past 40 years for Lake Taihu in the Yangtze River Delta, China

“…In general, a lake may change from a clear and macrophyte-dominated to a turbid and phytoplanktondominated ecosystem as a result of anthropogenic disturbance (Dokulil and Teubner 2003). Changes will also take place to the composition and biomass of the phytoplankton (Lessmann et al 2003), zooplankton (Xu et al 1999;Kulikova and Syarki 2004), benthic macroinvertebrates (Hellou and Law 2003;McCormick et al 2004), and fishes (Corsi et al 2003). These changes have been used as biological indicators to assess the health of aquatic ecosystems, including lakes (Xu et al 1999;2001), rivers (Reynolds 2003), marine bays (Boesch 2000) and oceans (Sherman 2000;Xu et al 2004).…”