The effects of oil sands wetlands on wood frogs (Rana sylvatica)

Extraction of crude oil from oil sand produces solid (sand) and liquid (water with suspended fine particles) tailings materials, called oil sands process-affected materials (OSPM). These waste materials are stored on the mine site due to a “zero discharge” policy and must be reclaimed when operations end. The liquid tailings materials are known to contain naphthenic acids and polycyclic aromatic hydrocarbons and have high pH and salinity. One method of reclamation is the “wet landscape” approach, which involves using oil sands tailings materials to form wetlands that would mimic natural wetland ecological function. This study investigated the effects of wetlands formed with oil sands tailings materials on the survival and growth of wood frog (Rana sylvatica) larvae. In spring 2007, in-situ caging studies were completed in 14 wetlands that were of four different classes; young or old, reference or reclaimed. Tadpole survival was different between types of wetlands, with young tailings-affected wetlands (≤7 years old) having 41.5%, 62.6%, and 54.7% higher tadpole mortality than old tailings-affected (>7 years old), young reference, and old reference wetlands, respectively. Since old wetlands created from OSPM showed effects on tadpoles similar to those of reference wetlands, which had markedly lower toxicity than young tailings-affected wetlands, we provide evidence that wetlands, at least 7 years old, can sustain amphibian life.     

Phytoplankton dynamics and species diversity in a shallow eutrophic,natural mid-altitude lake in Himachal Pradesh (India): role of physicochemical factors

Rewalsar Lake, a mid-altitude, shallow and recreational water body located in the north-western Himalayas, Himachal Pradesh (India) was studied through monthly surveys in two consecutive years (March 2008 to February 2010). Forty-seven species belonging to seven groups of phytoplankton were identified from the lake. Microcystis aeruginosa and Synedra ulna exhibited a perennial habit. Ankistrodesmus falcatus, Chlorella vulgaris, Scenedesmus bijugatus, Chlamydomonas reinhardi, Eudorina elegans, Navicula cuspidate, Synedra ulna, Euglena acus, Euglena oxyuris, Spirulina gomontii, Oscillatoria princeps and Arthrospira khannae were abundant, and Oscillatoria limosa and Microcystis aeruginosa were highly abundant. Twenty-one important criteria were studied, for example, temperature, free carbon dioxide, biochemical oxygen demand, total alkalinity, nitrate, silicate and phosphate, which provide an idea of the portability of water for irrigation and drinking purposes as per the permissible limits given in World Health Organization, Indian Council of Medical Research and Indian Standards Institute standards. Pearson's correlation revealed a significant relationship between physicochemical parameters and different algal groups. Both plankton and chlorophyll a showed a bimodal pattern of fluctuation. High annual mean concentrations of chlorophyll a (mg L^?1) were recorded as 11.44 in 2008–09, and 11.04 in 2009–10. As per the Palmer pollution index, 13 pollution-tolerant algal species with a pollution score of 37 were observed. The Central Pollution Control Board categorised the water at Rewalsar Lake as ‘D–E’.     

An Evaluation of Bivalves as Biomonitors of Heavy Metals Pollution in Marine Waters

Heavy metals (namely Cr, Cu, Zn, As, Hg, Pb, Ni, and Ag) that are present at concentrations common in ambient marine waters can cause adverse effects in shellfish. Such effects can significantly impact the trophic structure of a biological community. Heavy metals uptake is dependent on both geochemical and biological factors. In bivalves, the extent of accumulation is a function of several biotic and abiotic variables. Based on several criteria, (including: an ability to accumulate metals without suffering mortality, habitation within, and continuous exposure to, the contaminated matrix, hardiness, and ease of sampling) bivalve molluscs have proven to be useful biomonitors for a host of inorganic contaminants. It is essential that the biomonitoring plan is not only site specific, but that it considers the use of indigenous species whenever possible. This paper will provide a general review of studies that have employed bivalved shellfish as sentinel bioindicators in marine environments impacted by heavy metals, and give suggestions for conducting biomonitoring assays.     

Using Bacterial Growth on Insects to Assess Nutrient Impacts in Streams

A combination field and laboratorystudy was conducted to evaluate the ability of arecently developed bioindicator to detect detrimentalnutrient conditions in streams. The method utilizesbacterial growth on aquatic insects to determinenutrient impacts. Field investigations indicated thatelevated concentrations of nitrate and phosphate wereassociated with growth of filamentous bacteria oninsect body surfaces, and that there was a significantreduction in the density of major insect taxa in thenutrient-enriched stream reaches. Laboratoryinvestigations confirmed a strong linkage betweenbacterial growth and reduced survival of insects. Survival was examined for insects with bacterialinfestation ranging from 0% to greater than 50%coverage of the body surface. A threshold forcatastrophic mortality occurred at about 25% bodycoverage; there were few survivors above that amount. Based on these findings, the diagnostic endpoint forthe bioindicator is 25% body coverage by bacterialgrowth, a level that signifies major impacts and isalso easy to detect visually. This study providesadditional evidence that the insect-bacteriabioindicator is a reliable tool for assessing nutrientimpacts on stream macroinvertebrate communities. Thebioindicator should prove useful for identifyingnutrient-impacted sites as well as monitoring thesuccess of management actions to improve water quality.     

Eiseniella tetraedra (Savigny, 1826) (Oligochaeta: Lumbricidae) as a bioindicator of heavy metals

The objective of this study was to assess the potential of the earthworm Eiseniella tetraedra (Savigny, 1826) as a bioindicator for cadmium (Cd) and lead (Pb) exposure. The importance of earthworms in metal pollution monitoring is widely recognized in terrestrial ecosystems. In this study, the levels of Cd and Pb in soils and earthworm tissues were studied at two locations, Polur Falls and a riverside area located in Abali, in the Elburz Mountains in Iran. At both locations the concentration of Cd and Pb in earthworms was higher than in the surrounding soils and a significant difference was found between the two stations, the latter probably attributable to the (1) amount of pesticides that are used for crop treatment in Abali and (2) presence there of clay, which is known to be rich in Cd. Data indicate that E. tetraedra is an efficient bioaccumulator of Cd and Pb and might act thus serve as a bioindicator of exposure.     

Enteromorpha flexuosa (Wulfen) J. Agardh (Chlorophyta: Ulvales)--evaluation as an indicator of heavy metal contamination in a tropical estuary

The use of bioindicators for contaminant monitoring ispopular in all sectors of the environment but quite oftenbioindicators are utilised without rigorous evaluation oftheir viability as an indicator. We report field andlaboratory investigations into the value of a commonlyfound macroalga, Enteromorpha flexuosa (Wulfen) J.Agardh (Chlorophyta: Ulvales) as an indicator of copper,zinc and lead contamination in a tropical estuary inFiji. In the laboratory, metal content of E.flexuosa after 60 days of growth in seawater containingincreasing concentrations of the metals showed almostperfect correlation with metal concentrations in waterfor all three metals, and concentration factors obtainedwere generally higher than values reported for otherspecies of Enteromorpha. Performance in the fieldwas evaluated by a one-year monitoring of metals in E. flexuosa, water and sediments from a contaminatedestuary. Metal concentrations in water were always belowdetection limits and field concentration factors couldnot be determined but the concentration of lead in E. flexuosa showed a high correlation with the leadcontent of sediments. Lack of such correlation forcopper and zinc in the field suggests that otherenvironmental factors besides metal load in the physicalenvironment could be controlling the bioaccumulation ofthese two metals. Whilst demonstrating E. flexuosato be a viable bioindicator for lead, these results alsohighlight the need for proper assessment before anorganism is considered for environmental monitoring.     

Metaprotella Sandalensis (Crustacea: Amphipoda: Caprellidae): A Bioindicator of Nutrient Enrichment on Coral Reefs?

The population of the caprellid Metaprotella sandalensis Mayer (Crustacea: Amphipoda) associated with the seaweed Turbinaria ornata (Turner) J. Agardh was studied on a spatial scale in relation to the influence of physico-chemical factors on the coral reef system at Mauritius Island. Some areas of the coast of Mauritius are currently subject to disturbance due to industrialisation and rapidly growing tourist development programmes, meanwhile other sites of the island are still unaltered. T. ornata was sampled at 12 stations, distributed around the whole island to represent the heterogeneous conditions. The density of Metaprotella sandalensis living on T. ornata was measured. The linear regression and the multivariate analysis showed a strong correlation between the densities of the caprellid and the physico-chemical parameters. The highest densities of M. sandalensis were found in the most stressed sites characterised by the highest values of nitrate, phosphate, chemical oxygen demand and silting. According to these results and taking into account that M. sandalensis and T. ornata are widely distributed in most of the tropical ecosystems, we preliminarily propose usage of the density of this caprellid as a new monitoring tool on coral reefs or, at least, as a first diagnosis for the detection of nutrient enrichment on these ecosystems.     

Use of Central Stonerollers (Cyprinidae: Campostoma anomalum) from Tennessee as a Bioindicator of Metal Contamination

We compared the levels of arsenic, cadmium, chromium, lead, manganese, mercury and selenium in a small species of fish (Central stonerollers, Campostoma anomalum) collected from East Fork Poplar Creek (EFPC) and a reference site in eastern Tennessee. Stonerollers are minnows in the Cyprinidae family that serve as prey for many carnivores in aquatic systems. Fish were collected from East Fork Poplar Creek within the U.S. Department of Energy's Y-12 National Security Complex, part of the Oak Ridge Reservation, and from a reference stretch of the Little River in East Tennessee. Whole fish were homogenized for analysis. Concentrations of all metals (except arsenic) were significantly higher in stonerollers from EFPC compared to the reference site. Mercury levels in minnows from EFPC averaged 0.4 ppm (μg/g), four times higher than the average for fish in the U.S. in general. This was higher than levels in fish from the nearby Clinch River and higher than fillets of white bass (Morone chrysops) from the same creek. Most metal levels were inversely related to size and weight of the stonerollers, perhaps due to growth dilution.     

Tropical Coastal Organisms as Qualitative Indicators of Mercury and Organomercury for Sustainable Use of Living Resources

Organisms sensitive to ambient environment are used as bioindicators in monitoring pollution. The present investigation is designed to measure the extent of mercury and organomercury levels in selective biota of different trophic levels inhabiting in the coastal environment of Sunderban Biosphere Reserve, eastern part of India. The primary objective of this work is to provide baseline data for future environmental quality programme and to ascertain the suitability of these organisms to be used as bioindicator species of pollution. The seagrass (Porterasia coarctata), macrobenthos (polychaetes, gastropods and bivalve molluscs) and pelagic finfishes were collected from sites of different physiochemical characteristics. Concentration of total mercury was determined by cold vapour atomic absorption spectrophotometry technique (CVAAS) using a Perkin-Elmer 2380 AAS equipped with MHS 10.Both mercury and organomercury levels showed considerable interspecific and regional variations which reflected the feeding strategy of these animals and also the location of stations. The bivalve molluscs showed a high degree of organ-specificity in accumulation which might be attributed to the ion exchange activity of mucous membrane covering gill and mantle. Mercury levels in various compartments did not reveal any regular temporal variations but showed a slight increase in the late monsoon months indicating the apparent influence of river run-off and reduction in salinity in the ambient medium. A continuous monitoring programme is recommended in order to clarify the present trend and to establish the studied organisms as indicator species.     

Phragmites australis as a heavy metal bioindicator in the Anzali wetland of Iran

In this study, levels of Fe, Cu, Cd, and Ni in the sediments and organs of Phragmites australis from three different sites in the Anzali wetland were measured. Heavy metal accumulation was higher in the roots of P. australis than in the shoots and leaves. There was a significant correlation between metal concentrations in roots and sediment. This result showed that the root of P. australis can be used as bioindicator for Fe, Cu, Cd, and Ni. Metal levels in sediment were recorded higher than the interim sediment quality guideline values, and the Cd and Ni content in P. australis were higher than the unpolluted levels in plants. This indicates the necessity for continuous monitoring of the metal levels and also evaluating the hazard risk of heavy metals in aquatic organisms in the Anzali wetland.