Assessment of the pollution impact on biomarkers of effect of a freshwater fish

Changes in biomarkers of fish captured from stressed environments may represent a reliable tool in revealing sublethal effects of the pollutants found in aquatic ecosystems. The response patterns of selected biochemical and morphological variables biomarkers of effect were assessed in adult females of an indigenous teleost Cnesterodon decemmaculatus, caught at a polluted site (San Francisco) of the Reconquista river (Buenos Aires, Argentina). Combined field-caging experiments with controlled laboratory exposure to clean media were performed. The biochemical parameters measured were specific activities of gill (Na+ + K+)-ATPase, liver AlaAT and AspAT, and brain AChE; LSI and CF were also calculated. The changes in gill (Na+ + K+)-ATPase and liver AlaAT activities of fish captured in the field in most cases were reversible after transfer to clean media. The results were interpreted in association with the physicochemical profile of the water samples taken simultaneously with the capture of the fish. Results suggested the suitability of the test species used as tools in environmental monitoring programs of risk assessment.     

Circulation of copper in the biotic compartments of a freshwater dammed reservoir

This study concerns a chronic copper release in an aquatic ecosystem: Mirgenbach reservoir; which is characterized by high salinity, conductivity and hardness, a eutrophic state and a high temperature. To study the bioavailability of copper in the biotic compartments, the sampling covered the entire food chain (phyto- and zooplankton, macroalgae, aquatic plants, crustaceans, mollusks, and fish). Of the organisms present, the filter feeder Dreissena polymorpha, the detritivorous Bithynia tentaculata and Orconectes limosus were most contaminated by copper. The level of copper found in fish was the lowest. Body copper concentrations recorded in the present study show large variability between species even in some that are closely related. In most cases, however, the metal handling strategy, feeding habits, morphology and ecology can, at least partially, explain the metal content recorded. Pollution factors have been used to assess the state of contamination of the food chain. This study showed finally that the copper in the lake is bioavailable and bioaccumulated by organisms up to high levels and some effects of long-term toxicity of copper on benthic community and planktonic biomass were pointed out.     

Longterm effects of the herbicides Atrazine and Dichlobenil upon the phytoplankton density and physico-chemical conditions in compartments of a freshwater pond

Atrazine (1.1 mg · L^?1) and Dichlobenil (“DBN”) (4.3 mg · L^?1) were dosed in triplicates into the water of a compartimentalized pond. Maximum concentrations of the chemicals detected were 200 μg · L^?1 Atrazine and 4.2 mg · L^?1 DBN (on day 3 – 5 after dosing). Residues were monitored for 55 days, amounting to 60 μg Atrazine and 1.5 mg DBN per litre at the end of observation.O₂- and H⁺-concentrations were significantly lower for 35 and 30 days resp. in the treated water as compared to controls. The conductivity of the dosed water was significantly higher for at least 65 (DBN) and 120 days (Atrazine) than in the untreated compartments. Differences in phytoplankton abundance and diversity could be evaluated between controls and treated biotopes.     

Acute effects of copper and mercury on the estuarine fish Pomatoschistus microps: Linking biomarkers to behaviour

The main objective of the present study was to investigate possible links between biomarkers and swimming performance in the estuarine fish Pomatoschistus microps acutely exposed to metals (copper and mercury). In independent bioassays, P. microps juveniles were individually exposed for 96 h to sub-lethal concentrations of copper or mercury. At the end of the assays, swimming performance of fish was measured using a device specially developed for epibenthic fish (SPEDE). Furthermore, the following biomarkers were measured: lipid peroxidation (LPO) and the activity of the enzymes acetylcholinesterase (AChE), lactate dehydrogenase (LDH), glutathione S-transferases (GST), 7-ethoxyresorufin-O-deethylase (EROD), superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR) and glutathione peroxidase (GPx). LC₅₀s of copper and mercury (dissolved throughout metal concentrations) at 96 h were 568 μg L⁻¹ and 62 μg L⁻¹, respectively. Significant and concentration-dependent effects of both metals on swimming resistance and covered distance against water flow were found at concentrations equal or higher than 50 μg L⁻¹ for copper and 3 μg L⁻¹ for mercury (dissolved throughout metal concentrations). These results indicate that SPEDE was efficacious to quantify behavioural alterations in the epibenthic fish P. microps at ecologically relevant concentrations. Significant alterations by both metals on biomarkers were found including: inhibition of AChE and EROD activities, induction of LDH, GST and anti-oxidant enzymes, and increased LPO levels, with LOEC values ranging from 25 to 200 μg L⁻¹ for copper and from 3 to 25 μg L⁻¹ for mercury (dissolved throughout metal concentrations). Furthermore, significant and positive correlations were found between some biomarkers (AChE and EROD) and behavioural parameters, while negative correlations were found for others (LPO, anti-oxidant enzymes and LDH) suggesting that disruption of cholinergic function through AChE inhibition, decreased detoxification capability due to EROD inhibition, additional energetic demands to face chemical stress, and oxidative stress and damage may contribute to decrease the swimming performance of fish. Since a reduced swimming capability of fish may reduce their ability to capture preys, avoid predators, and interfere with social and reproductive behaviour, the exposure of P. microps to copper and/or mercury concentrations similar to those tested here may decrease the fitness of wild populations of this species.     

Structural and functional responses of a freshwater plankton community to acute copper stress

An in-situ experiment was performed to quantify the impacts of copper sulfate on plankton structure and carbon dynamics. Plankton were exposed to 140 microg litre(-1) copper in quadruplicate mesocosms. Community structure was monitored for 14 days by microscopical counts and compared with untreated controls. Carbon dynamics were assessed by tracer studies using (14)C bicarbonate and (14)C glucose, to follow the fate of carbon in the algal- and bacterial-based pathways, respectively. Copper reduced the dry-weight biomass of zooplankton, ciliates, flagellates, and autotrophic phytoplankton. Bacterial biomass was increased by an order of magnitude relative to the controls. The bacterial response was most likely due to reduced grazing pressure and/or nutrient release from dying plankton. Copper reduced the effectiveness of the food web in transporting carbon to the surviving zooplankton. Bacterial-based pathways were more greatly affected than algal-based pathways, because zooplankton in the copper treatment were macro-grazers (cyclopoids), which cannot utilize bacteria.     

Climate change effects on hydroecology of arctic freshwater ecosystems

In general, the arctic freshwater-terrestrial system will warm more rapidly than the global average, particularly during the autumn and winter season. The decline or loss of many cryospheric components and a shift from a nival to an increasingly pluvial system will produce numerous physical effects on freshwater ecosystems. Of particular note will be reductions in the dominance of the spring freshet and changes in the intensity of river-ice breakup. Increased evaporation/evapotranspiration due to longer ice-free seasons, higher air/water temperatures and greater transpiring vegetation along with increase infiltration because of permafrost thaw will decrease surface water levels and coverage. Loss of ice and permafrost, increased water temperatures and vegetation shifts will alter water chemistry, the general result being an increase in lotic and lentic productivity. Changes in ice and water flow/levels will lead to regime-specific increases and decreases in habitat availability/quality across the circumpolar Arctic.     

Relationship between water solubility of chlorobenzenes and their effects on a freshwater green alga

The effective concentrations of benzene and 12 chlorobenzenes that reduced 50% of the primary productivity (EC₅₀) of a freshwater green alga, $\text{Ankistrodesmus falcatus}$, were determined. Benzene was the least toxic chemical and the toxicity increased as the degree of chlorine substitution in the aromatic ring increased. No EC₅₀ value could be obtained for HCB. A quantitative relationship was found to exist between water solubility, lipophilicity and the EC₅₀. A good correlation was also observed between the EC₅₀ for this alga and other toxicity data for various aquatic biota.     

Evaluation of impact of PAH on a tropical fish, Oreochromis mossambicus using multiple biomarkers

Treatment of the widely occurring tropical cichlid, Oreochromis mossambicus with a pure polycyclic aromatic hydrocarbon (PAH), phenanthrene, induced a concentration-dependant formation of the enzyme, 7-ethoxyresorufin-O-deethylase (EROD). Concomittant increase (65-669%) in the activity of sorbitol dehydrogenase in the serum (SSDH) occurring with EROD induction denoted liver cell damage, which was more severe in fish exposed to lower concentrations (0.4-4 microg g-1) of the chemical. In O. mossambicus exposed to 25% refinery effluent liver damage associated with cell death was indicated by the twin analyses of SSDH and liver somatic index. Cell injury appeared to have occurred at low PAH concentrations due to inadequately induced phase II-related detoxification of metabolites. This was indicated by the nearly 33% higher activity of hepatic glutathione S-transferase (GST) in fish exposed to higher PAH concentrations as compared to low-exposure animals. Tilapia such as O. mossambicus were found to be eminently suited for biomonitoring in tropical coastal waters. A combination of EROD and serum sorbitol dehydrogenase activity measurements serves as an excellent tool for biomonitoring sublethal effects of PAH pollution in fish.     

An experimental comparison of the effects of two chemical stressors on a freshwater zooplankton assemblage

Mesocosms in an Ohio, USA lake were dosed with ten levels (0-100 microg liter(-1)) of copper (experiment 1) or Carbaryl (experiment 2). Zooplankton responses were determined after 4-day incubations. Species level responses differed for the two chemicals; community level responses were very similar. Across the gradients of increasing Cu or Carbaryl doses, cladocerans were greatly reduced and copepods became dominant. For Carbaryl, the response was consistent with that reported previously. For Cu, different responses were previously observed at other lakes. The taxonomic composition of the zooplankton may largely determine the community level response. In the present experiments, cladoceran declines may have secondarily affected food web function. In the Carbaryl experiment, where the chemical did not directly suppress algae, their biomass increased with dose level. This coincided with the cladoceran decline, suggesting an algal response to reduced top-down control.     

基于Vague集的集对分析在湖泊富营养化评价中的应用

针对湖泊富营养化评价的不确定型多属性决策问题,提出了Vague集的集对分析模型,详细介绍了集对分析和Vague集的基本理论、Vague集的表示方法和Vague集相似度的同异反状态关系.建立了湖泊富营养化评价指标体系,引入了超标权重确定各湖泊指标权重,再依据待评湖泊关于等级i特征的Vague集和理想Vague集的相似度构成特征值法确定评价等级,并应用该模型对我国9个湖泊的富营养化程度进行了评价,该方法的评价结果与实际情况基本相符,为湖泊的治理和保护提供了科学依据.     

Evaluation of caged freshwater mussels as an alternative method for environmental effects monitoring (EEM) studies

On three occasions between 1998 and 2000, freshwater mussels were collected by divers in Lake Memphremagog during the spring and transplanted to various locations in the St-Fran?ois River (Quebec, Canada). Mussel growth was monitored by comparing total weight and length at the beginning and end of the exposure period. In 1998, mussels were caged for 60 days at 10 stations, including locations receiving treated effluents from three pulp and paper mills. Overall, there was an apparent trend of increased mussel growth from upstream to downstream along the river. However, mussels caged downstream from the effluent discharge of a bleached kraft pulp and paper mill grew more slowly than those caged immediately upstream in the river. In 1999 and 2000, we further investigated the situation in the vicinity of this bleached kraft mill. The measurements again indicated that growth of mussels in the effluent plume from this mill was reduced in comparison to sites upstream. Overall, in terms of growth, the caged mussels responded both positively and negatively to different environmental conditions. Compared with other monitoring approaches used at these sites during the same period, the caged mussel experiment results were consistent with the trends observed with the benthic invertebrate survey but not with the trends observed for fish.     

The effects of fenvalerate on different tissues of freshwater fish Cirrhinus mrigala

The histopathological changes of fenvalerate on the gill, kidney, liver and intestine tissues of the Cirrhinus mrigala were determined by light microscopy. The fish were exposed to two sub-lethal concentrations of fenvalerate (1.5-3.0 ppb). The most common gill changes at all concentrations of fenvalerate were epithelial hyperplasia, epithelial necrosis, desquamation and lamellar fusion. Besides, epithelial lifting, oedema, swelling at the tips of secondary lamellae and curling of secondary lamellae were other histopathological changes. Necrosis of tubular epithelium, pycnotic nuclei in the hematopoietic tissue, hypertrophied epithelial cells of renal tubules, narrowing of the tubular lumen, expansion of space inside the Bowman's capsule and contraction of the glomerulus were observed in kidney tissues of fish. Hepatic lesions in the liver tissues of fish exposed to fenvalerate were characterized by congestion, cloudy swelling of hepatocytes and focal necrosis. Atrophy of epithelial cells, necrosis of epithelial cells, desquamation of mucosal epithelium and infiltration of lymphocytes into the lamina propria were detected in intestine tissues of fish after exposure to fenvalerate.     

Toxic effects of endocrine disrupters on freshwater sponges: common developmental abnormalities

Endocrine disrupters are of substantial concern, in large part because effects of these compounds on the growth and development of many aquatic organisms are unknown. We examined toxic effects of three substances (ethylbenzene, nonylphenol, and bisphenol A), that are known to be hormonally active in many animals, on growth and development of two species of freshwater sponge. A common developmental abnormality was observed when sponges were treated with each of these compounds. The three compounds also caused significant reductions in growth rates. Lower concentrations resulted in malformed water vascular systems in several replicates. The utility of freshwater sponge bioassays is discussed as it relates to understanding possible mechanisms of action of endocrine disrupters on aquatic invertebrates.     

铜对活性污泥微生物活性影响研究

通过人工投加铜离子对驯化污泥的破坏性实验,研究了各浓度铜离子对活性污泥氨氮、COD降解的影响及其TTC-脱氢酶活性、氧摄取速率(SOUR)、氨摄取速率(AUR)的影响。结果显示,0~5 mg/L的铜离子对处理系统有机物的去除率影响不大。铜离子浓度与活性污泥的TTC-脱氢酶活性、SOUR以及AUR之间呈现良好的相关性;低浓度的铜离子对TTC-脱氢酶活性和SOUR均有一定的促进作用,而对AUR则会产生一定的抑制作用。当铜离子浓度达到5 mg/L时,其对SOUR、TTC-脱氢酶活性以及AUR的抑制率均超过50%。在此情况下,采用TTC-脱氢酶活性、SOUR以及AUR等指标,能快速有效地表征铜离子对活性污泥微生物的毒害作用。     

Use of hematological and plasma biochemical parameters to assess the chronic effects of a fungicide propiconazole on a freshwater teleost

Blood is an indicator of physiological condition of an animal. Therefore, the chronic effects of propiconazole, a triazole fungicide present in aquatic environment, on hematology of rainbow trout were investigated in this study. Fish were exposed at various concentrations of PCZ (0.2, 50 and 500 μg L(-1)) for 7, 20 and 30 d. Multiple biomarkers were measured, including hematological indices (hemoglobin concentration, red blood cells count, hematocrit, leukocyte count, mean erythrocyte hemoglobin, mean erythrocyte volume and mean color concentration) and plasma biochemical parameters (ammonia, glucose, total proteins, creatine kinase, lactate dehydrogenase, alanine aminotransferase and aspartate aminotransferase). Through principal component analysis and integrated biomarker response assessment, influence extent induced by PCZ-stress of each test group was distinguished. Additional, all parameters measured in this study displayed different dependent patterns to PCZ concentrations and exposure time by two-way ANOVA. The results of this study indicate that chronic exposure of PCZ has altered multiple physiological indices in fish hematology and CK activity may be an early biomarker of PCZ toxicity; however, before these parameters are used as special biomarkers for monitoring residual PCZ in aquatic environment, more detailed experiments in laboratory need to be performed in the future.     

Evaluation of a Gaussian and a Lagrangian model against a roadside data set,with emphasis on low wind speed conditions

The evaluation of the high percentiles of concentration distributions is required by most national air quality guidelines, as well as the EU directives. However, it is problematic to compute such high percentiles in stable, low wind speed or calm conditions. This study utilizes the results of a previous measurement campaign near a major road at Elimäki in southern Finland in 1995, a campaign specifically designed for model evaluation purposes. In this study, numerical simulations were performed with a Gaussian finite line source dispersion model CAR-FMI and a Lagrangian dispersion model GRAL, and model predictions were compared with the field measurements. In comparison with corresponding results presented previously in the literature, the agreement of measured and predicted data sets was good for both models considered, as measured using various statistical parameters. For instance, considering all NO_x data (N=587), the so-called index of agreement values varied from 0.76 to 0.87 and from 0.81 to 1.00 for the CAR-FMI and GRAL models, respectively. The CAR-FMI model tends to slightly overestimate the NO_x concentrations (fractional bias FB=+14%), while the GRAL model has a tendency to underestimate NO_x concentrations (FB=−16%). The GRAL model provides special treatment to account for enhanced horizontal dispersion in low wind speed conditions; while such adjustments have not been included in the CAR-FMI model. This type of Lagrangian model therefore predicts lower concentrations, in conditions of low wind speeds and stable stratification, in comparison with a standard Lagrangian model. In low wind speed conditions the meandering of the flow can be quite significant, leading to enhanced horizontal dispersion. We also analyzed the difference between the model predictions and measured data in terms of the wind speed and direction. The performance of the CAR-FMI model deteriorated as the wind direction approached a direction parallel to the road, and for the lowest wind speeds. However, the performance of the GRAL model varied less with wind speed and direction; the model simulated better the cases of low wind speed and those with the wind nearly parallel to the road.     

Metabolomics identifying biomarkers of PM2.5 exposure for vulnerable population: based on a prospective cohort study

Long-term exposure to particular matter (PM), especially fine PM (< 2.5 μm in the aerodynamic diameter, PM_2.5), is associated with increased risk of cardiovascular disorders. This study aimed to evaluate the association between long-term exposure to PM_2.5/PM₁₀ and the metabolic change in the plasma. Specifically, using metabolomics, we sought to identify the biomarkers for the vulnerable subgroup to PM_2.5 exposure. A total of 78 college student volunteers were recruited into this prospective cohort study. All participants received 8 rounds of physical examinations at twice quarterly. Air purifiers were placed in 40 of 78 participants’ dormitories for 14 days. Before and after intervention, physical examinations were performed and the peripheral blood was collected. Plasma metabolomics was determined by ultra-performance liquid chromatography-mass spectrometry. During the follow-up, the average concentrations of PM_2.5 and PM₁₀ were 53 μg/m³ and 93 μg/m³, respectively. Totally, 42 and 120 differential metabolic features were detected for PM₁₀ and PM_2.5 exposure, respectively. In total, 25 differential metabolites were identified for PM_2.5 exposure, most of which were phospholipids. No distinctive metabolites were found for PM₁₀ exposure. A total of 6 differential metabolites (lysoPC (P-20:0), lysoPC (P-18:1(9z)), lysoPC (20:1), lysoPC (O-16:0), choline, and found 1,3-diphenylprop-2-en-1-one) were characterized and confirmed for sensitive individuals. Importantly, we found LysoPC (P-20:0) and LysoPC (P-18:1(9z)) changed significantly before and after air purifier intervention. Our results indicated that the phospholipid catabolism was involved in long-term PM_2.5 exposure. LysoPC (P-20:0) and LysoPC (P-18:1(9z)) may be the biomarkers of PM_2.5 exposure.

     

Multiple biomarkers of pollution effects in Solea solea fish on the Tunisia coastline

This field study investigates the morphological indices (condition index, hepatosomatic index) and biochemical (catalase (CAT), glutathione S-transferase (GST), acetylcholinesterase (AChE), metallothionein (MT), lipid peroxidation) parameters in liver, gills and kidney of common sole (Solea solea) originating from different sites of the Tunisian coast area impacted by different anthropogenic activities. Differences among sites and tissues for AChE, GST, CAT, MT and TBARS were found and possibly related to known sources of domestic and industrial discharges in the studied sites. Liver, gills and kidney CAT, liver and kidney MT and brain AChE were key biomarkers to discriminate fish of different sites. So, we suggest using these biomarkers in future biomonitoring.     

The effects of copper ions and copper nanomaterials on the output of amino acids from marine microalgae

In this study, the marine microalgae Skeletonema costatum and Nitzschia closterium were exposed to different forms of copper, such as a metal salt (Cu²⁺), a nano-metal (nano-Cu), and nano-metal oxide (nano-CuO). During a 96-h exposure to nanoparticles (NPs) and salt, the cell number, Cu²⁺ concentration in the culture medium, morphology, and intracellular amino acids were measured to assess the toxicity of the copper materials and the toxicity mechanism of the NPs. As results, the toxicity of Cu²⁺, nano-Cu, and nano-CuO to marine phytoplankton decreased in order. The EC₅₀ values of Cu²⁺ and nano-Cu for S. costatum and N. closterium ranged from 0.356 to 0.991 mg/L and 0.663 to 2.455 mg/L, respectively. Nano-Cu inhibits the growth of marine phytoplankton by releasing Cu²⁺; however, nano-CuO is harmful to microalgae because of the effect of NPs. The secretion of extracellular polymeric substances by microalgae could also affect the toxicity of nano-Cu and nano-CuO to microalgae. S. costatum was more sensitive to copper than N. closterium. Cu²⁺, nano-Cu, and nano-CuO all reduced per-cell amino acids and the total output of algae-derived amino acids by affecting the growth of the phytoplankton. This study helps to understand the risk assessment of nano-Cu and nano-CuO to marine microalgae.

     

An overview of effects of climate change on selected arctic freshwater and anadromous fishes

Arctic freshwater and diadromous fish species will respond to the various effects of climate change in many ways. For wide-ranging species, many of which are key components of northern aquatic ecosystems and fisheries, there is a large range of possible responses due to inter- and intra-specific variation, differences in the effects of climate drivers within ACIA regions, and differences in drivers among regions. All this diversity, coupled with limited understanding of fish responses to climate parameters generally, permits enumeration only of a range of possible responses which are developed here for selected important fishes. Accordingly, in-depth examination is required of possible effects within species within ACIA regions, as well as comparative studies across regions. Two particularly important species (Arctic char and Atlantic salmon) are examined as case studies to provide background for such studies.