Integrated environmental assessment of Volturno River in South Italy

The application of a battery of toxicity and genotoxicity tests on pore water in parallel and in combination with physico-chemical analyses and benthic macroinvertebrate community investigations is discussed as a tool to assess the environmental quality of the Volturno River in South Italy. Toxicity testing was performed on the rotifer Brachionus calyciflorus and the crustacean Daphnia magna. Genotoxicity was determined by the SOS chromotest and Mutatox system. The biotic index used for macroinvertebrates was the extended biotic index that was developed to verify if the observed benthic community accords with the expected one for an identical environment without anthropic contaminations. The physico-chemical characterization of the surface waters showed a declining trend from up-river to down-river for dissolved oxygen and conductivity. Also, chemical variables showed a worsening along the river axis showing an increase in ammonium, phosphates, sulfates, and heavy metals. The assessment of macro-invertebrates reflected the general ecological deterioration occurring to chemical as well as toxic and genotoxic pollution. Furthermore, benthic community composition and the sediment contamination of toxic and genotoxic substances were shown to be correlated. We concluded that investigations on pore water, integrated with benthic macroinvertebrate communities, could provide the basis for a robust monitoring of rivers.     

Assessing land-use effects on water quality, in-stream habitat, riparian ecosystems and biodiversity in Patagonian northwest streams

Changes in land-use practices have affected the integrity and quality of water resources worldwide. In Patagonia there is a strong concern about the ecological status of surface waters because these changes are rapidly occurring in the region. To test the hypothesis that greater intensity of land-use will have negative effects on water quality, stream habitat and biodiversity we assessed benthic macroinvertebrates, riparian/littoral invertebrates, fish and birds from the riparian corridor and environmental variables of 15 rivers (Patagonia) subjected to a gradient of land-use practices (non-managed native forest, managed native forest, pine plantations, pasture, urbanization). A total of 158 macroinvertebrate taxa, 105 riparian/littoral invertebrate taxa, 5 fish species, 34 bird species, and 15 aquatic plant species, were recorded considering all sites. Urban land-use produced the most significant changes in streams including physical features, conductivity, nutrients, habitat condition, riparian quality and invertebrate metrics. Pasture and managed native forest sites appeared in an intermediate situation. The highest values of fish and bird abundance and diversity were observed at disturbed sites; this might be explained by the opportunistic behavior displayed by these communities which let them take advantage of increased trophic resources in these environments. As expected, non-managed native forest sites showed the highest integrity of ecological conditions and also great biodiversity of benthic communities. Macroinvertebrate metrics that reflected good water quality were positively related to forest land cover and negatively related to urban and pasture land cover. However, by offering stream edge areas, pasture sites still supported rich communities of riparian/littoral invertebrates, increasing overall biodiversity. Macroinvertebrates were good indicators of land-use impact and water quality conditions and resulted useful tools to early alert of disturbances in streams. Fish and birds having a greater ability of dispersion and capacity to move quickly from disturbances would reflect changes at a higher scale.     

Patterning and predicting aquatic macroinvertebrate diversities using artificial neural network

A counterpropagation neural network (CPN) was applied to predict species richness (SR) and Shannon diversity index (SH) of benthic macroinvertebrate communities using 34 environmental variables. The data were collected at 664 sites at 23 different water types such as springs, streams, rivers, canals, ditches, lakes, and pools in The Netherlands. By training the CPN, the sampling sites were classified into five groups and the classification was mainly related to pollution status and habitat type of the sampling sites. By visualizing environmental variables and diversity indices on the map of the trained model, the relationships between variables were evaluated. The trained CPN serves as a 'look-up table' for finding the corresponding values between environmental variables and community indices. The output of the model fitted SH and SR well showing a high accuracy of the prediction (r>0.90 and 0.67 for learning and testing process, respectively) for both SH and SR. Finally, the results of this study, which uses the capability of the CPN for patterning and predicting ecological data, suggest that the CPN can be effectively used as a tool for assessing ecological status and predicting water quality of target ecosystems.     

Water toxicity assessment and spatial pollution patterns identification in a Mediterranean River Basin District. Tools for water management and risk analysis

In compliance with the requirements of the EU Water Framework Directive, monitoring of the ecological and chemical status of Catalan river basins (NE Spain) is carried out by the Catalan Water Agency.The large amount of data collected and the complex relationships among the environmental variables monitored often mislead data interpretation in terms of toxic impact, especially considering that even pollutants at very low concentrations might contribute to the total toxicity.The total dataset of chemical monitoring carried out between 2007 and 2008 (232 sampling stations and 60 pollutants) has been analyzed using sequential advanced modeling techniques. Data on concentrations of contaminants in water were pre-treated in order to calculate the bioavailable fraction, depending on substance properties and local environmental conditions.The resulting values were used to predict the potential impact of toxic substances in complex mixtures on aquatic biota and to identify hot spots. Exposure assessment with Species Sensitivity Distribution (SSD) and mixture toxicity rules were used to compute the multi-substances Potentially Affected Fraction (msPAF).The combined toxicity of the pollutants analyzed in the Catalan surface waters might potentially impact more than 50% of the species in 10% of the sites.In order to understand and visualize the spatial distribution of the toxic risk, Self Organising Map (SOM), based on the Kohonen's Artificial Neural Network (ANN) algorithm, was applied on the output data of these models. Principal Component Analysis (PCA) was performed on top of Neural Network results in order to identify main influential variables which account for the pollution trends. Finally, predicted toxic impacts on biota have been linked and correlated to field data on biological quality indexes using macroinvertebrate and diatom communities (IBMWP and IPS). The methodology presented could represent a suitable tool for water managers in environmental risk assessment and management.     

A comparison between various criteria for the interpretation of biological data in the analysis of the quality of running waters

In this work it is proposed to apply the most common biological criteria for the assessment of water quality to the macroinvertebrate populations in the Torrente Parma. The data concerning both the structure and the dynamics of the macroinvertebrate community over 1 yr have been analysed through the species diversity indexes, the saprobien index and the biotic indexes of Woodiviss and Verneaux-Tuffery. The values obtained by applying the various indexes have been compared. A tentative conversion scale has been developed between the indexes which have given the highest degree of correlation.Furthermore, a synthetic representation of the annual species distribution has been obtained using cluster analysis and Fager's affinity index.     

A trait database of stream invertebrates for the ecological risk assessment of single and combined effects of salinity and pesticides in South-East Australia

We compiled a database on a priori selected traits for South-East Australian freshwater macroinvertebrate families and used this data for the development of a biotic indicator for the detection of the effects of salinisation on freshwater communities (SPEAR_salinity) and for the adaptation of the existing SPEAR_pesticides index for South-East Australian taxa. The SPEAR_salinity indicator showed a reasonably high relationship (0.38 ≤ r² ≤ 0.5) with salinity in terms of logarithmic electrical conductivity (log EC) using field biomonitoring data from 835 pools and riffle sites in Victoria and South Australia. Several other biotic indexes that were calculated for comparison purpose exhibited a lower relationship with log EC. In addition, SPEAR_salinity was the only indicator that did not respond to other water quality variables and was therefore most selective. We used log EC data and modelled pesticide exposure for sites in Victoria in concert with SPEAR_salinity and the existing SPEAR_pesticides index to assess whether pesticides interacts with effects of salinity on invertebrate communities and vice versa. No interaction with pesticides was found for the effect of log EC on SPEAR_salinity, whereas EC interacted with the estimated pesticide exposure on the invertebrate communities. To foster the development of further trait-based ecological indicators, we suggest a conceptual model that predicts response traits based on the disturbance regime and disturbance mode of action of the stressor. Biotic indicators based on a priori selected traits represent a promising biomonitoring tool even for regions where ecological information is scarce.     

Linking catchment characteristics and water chemistry with the ecological status of Irish rivers

Requirements of the EU Water Framework Directive for the introduction of ecological quality objectives for surface waters and the stipulation that all surface waters in the EU must be of 'good' ecological status by 2015 necessitate a quantitative understanding of the linkages among catchment attributes, water chemistry and the ecological status of aquatic ecosystems. Analysis of lotic ecological status, as indicated by an established biotic index based primarily on benthic macroinvertebrate community structure, of 797 hydrologically independent river sites located throughout Ireland showed highly significant inverse associations between the ecological status of rivers and measures of catchment urbanisation and agricultural intensity, densities of humans and cattle and chemical indicators of water quality. Stepwise logistic regression suggested that urbanisation, arable farming and extent of pasturelands are the principal factors impacting on the ecological status of streams and rivers in Ireland and that the likelihood of a river site complying with the demands of the EU Water Framework Directive, and be of 'good' ecological status, can be predicted with reasonable accuracy using simple models that utilise either widely available landcover data or chemical monitoring data. Non-linear landcover and chemical 'thresholds' derived from these models provide a useful tool in the management of risk in catchments, and suggest strongly that more careful planning of land use in Ireland is essential in order to restore and maintain water quality as required by the Directive.     

In situ tests for water quality assessment: a case study in Pampean rivers

Two invertebrate species (Hyalella curvispina and Palaemonetes argentinus) and one macrophyte (Egeria densa) from a naturally high nutrient content system (Pampean rivers of La Plata, Argentina) were evaluated for their potential use in situ assays aiming to assess changes in water quality. Invertebrates were individually placed in cylindrical chambers in polluted sections of rivers and in reference upstream sites. Mortality after 48 h was high in polluted and reduced in control sites. Mortality was also higher in situ assays than in laboratory static tests. Standard sections of the macrophyte were also deployed at the reference and control sites. Growth (7 days) in terms of mass increment (but not in length) was consistently reduced in polluted sites. Results of benthic invertebrate and periphitic algae surveys were consistent with the in situ tests: pollution resulted in a decrease in the number of taxa, taxa replacement and in changes in the value of the biotic indices Indice Biótico PAMPeano and Indice de Diatomeas Pampeano, indicating deterioration of water quality. In situ assays have a high potential as environmental tools in integrated approaches of bioassessment programs.     

Modelling aquatic exposure and effects of insecticides--application to south-eastern Australia

Agricultural pesticides are widely used and can affect freshwater organisms. We applied a spatially explicit exposure model, validated for central Europe, to estimate exposure to insecticides through runoff for streams in south-eastern Australia. The model allows the identification of streams potentially affected by insecticide runoff located in 10 × 10 km grid cells. The computation of runoff relies on key environmental factors such as land use, soil texture, slope and precipitation. Additionally, the model predicted the ecological effect of insecticides on the macroinvertebrate community. We predicted insecticide surface runoff that results in a moderate to poor ecological quality for streams in half of the grid cells containing agricultural land. These results are in good accordance with the results obtained by estimating pesticide stress with a biotic index (SPEAR_pesticides) based on macroinvertebrate monitoring data. We conclude that the exposure and effect model can act as an effective and cost-saving tool to identify high risk areas of insecticide exposure and to support stream management.     

Using a battery of bioassays, benthic phytoplankton and the AUSRIVAS method to monitor long-term coal tar contaminated sediment in the Cache la Poudre River, Colorado

This survey provides information on sediment toxicity and structural characteristics of the macroinvertebrates and benthic phytoplankton at 10 locations in the Cache la Poudre River after long-term exposure to coal tar residue. The application of the Australian river bioassessment system (AUSRIVAS) as well as a biotest battery was used to evaluate the river ‘health’ condition. Coal tar is a dense nonaqueous-phase liquid of significant environmental concern due to its toxicity and persistence in the subsurface. Organisms like Selenastrum capricornutum, Daphnia magna and Chironomus tentans, representing different complexities in the biosphere, were selected as test systems for ecotoxicological studies. The results obtained in this study indicate that a biotest battery, macroinvertebrate and benthic phytoplankton communities are in principle suitable biological tools for evaluation of toxic oil and coal-derived substances in long-term contaminated river sediment.     

Spatial and temporal effects of olive mill wastewaters to stream macroinvertebrates and aquatic ecosystems status

Olive mill wastewater (OMW) is one of the major and most challenging organic pollutants in olive oil production countries. However, the knowledge about the in-situ effects of olive mill wastewaters to lotic ecosystems and their benthic organisms is very limited. To resolve this, eight sampling sites were selected upstream and downstream the outflow of several olive mills to assess the spatial and temporal effects of OMW to stream macroinvertebrates and to ecological status of stream ecosystems. Biotic (macroinvertebrates) and abiotic (physicochemical, hydromorphological) data were monitored for two years thus following the biennial cycle of olive growth and production and hydrological variation (drought-wet years). The results of this study revealed the spatial and temporal structural deterioration of the aquatic community due to OMW pollution with consequent reduction of the river capacity for reducing the effects of polluting substances through internal mechanisms of self-purification. OMW, even highly diluted, had dramatic impacts on the aquatic fauna and to the ecological status of the receiving stream ecosystems. The organic load of the wastewater expressed as BOD₅, COD and TSS, substrate contamination (sewage bacteria) and distance from the mill outlet, were the most important factors affecting macroinvertebrate assemblages while the typology (i.e. slope, altitude) and hydrology of the stream site (i.e. mountainous-lowland) and the intensity and volume of the wastewater were the most important determinants of self-purification processes. As OMW are usually being discharged in small size streams that are not considered in the Water Framework Directive 2000/60/EC, there is a need for including such systems into monitoring and assessment schemes as they may significantly contribute to the pollution load of the river basin. Furthermore, guidelines to manage these wastes through technologies that minimise their environmental impact and lead to a sustainable use of resources are critical.     

Species-specific responses of two benthic invertebrates explain their distribution along environmental gradients in freshwater habitats

The absence of species in polluted sediments does not necessarily imply exclusion due to toxicity. Other factors, like for instance food availability and oxygen content, could also partly cause their absence. Hence, knowledge of the (combinations of) factors acting on individual organisms is essential in order to understand how populations can persist in polluted sediments. In this study species-specific responses of two benthic invertebrate species, the mayfly Ephoron virgo and the midge Chironomus riparius, to environmental variables were compared. It was assessed how these responses determine the distribution of these species in polluted sediments. Subsequently, it was discussed how these results can assist in the formulation and implementation of policies with respect to the ecological risks of pollution to benthic invertebrates. The present study showed that sediment pollution is likely to act only occasionally as a single selective force reducing the persistence of sensitive species. Yet, it was shown in our studies that the pollution level in some tested sediments limits the persistence of insects with the sensitivity of E. virgo. In other cases, however, a combination of conditions is likely to determine their persistence. As shown here for C. riparius, sediment pollution drives this species close to intoxication, but a high availability of food enables them to persist very well. The present study provides evidence that pollution levels exceeding current Dutch Negligible Concentrations may pose a detectable ecological effect at least for sensitive benthic invertebrates.     

Dynamics of metal availability and toxicity in historically polluted floodplain sediments

Many floodplains contain high concentrations of sediment associated contaminants that might be subjected to large changes in terms of mobility, transformation and bioavailability. Therefore, this study describes 1) changes in the redox conditions and the mobility of metals in artificially uncovered polluted floodplain sediments, 2) metal uptake by organisms and 3) colonization, succession and functioning of benthic algae on these sediments. Flooding caused long term changes in redox potential (Eh) profiles. In top layers strong gradients in redox potential established quickly, while in deeper layers changes occurred more gradually. The availability of copper as measured by Diffusive Gradients in Thinfilms (DGT) showed a consistent relationship with fluctuations in Eh. However, this relationship was restricted to deeper layers in the sediment. Within 1 week high amounts of total copper were immobilized. Differences in total copper concentrations between polluted and clean sediments became only partially apparent when comparing the available copper fraction (DGT-Cu). Introduced Tubifex shows only marginal differences in levels of accumulated Cu. Colonization, growth and succession of algal communities on polluted sediments was not impaired, most likely due to low bioavailability. It is concluded that changing environmental conditions, such as flooding, can result in stable chemical conditions with low a availability of metals and hence in a diminution of actual ecological risks.     

The two sides of man-induced changes in littoral marine communities: Eastern Mediterranean and the Red Sea as an example

Over the last two centuries, the marine life of the Eastern Mediterranean has been influenced by two major factors: one is beneficial, and concerns species migration, such as the opening of the Suez Canal, which enriched the impoverished eastern Mediterranean Sea with over 300 species of fish and invertebrates of Red Sea origin; while the other, a negative and possibly wider-reaching factor, is that of man-made pollution, which has induced unpredictable changes, destabilizing the biological world in both magnitude and duration. Initially cryptic, the effects caused by pollutants first occur at the biochemical and cellular levels of an organism, causing alterations and deviations from the normal, strongly mobilizing its defense systems. Conventional methodologies of ecological analyses, based on species and specimen numbers, cannot detect such alterations. Studying several mollusk populations from polluted and reference sites of the Red Sea and Mediterranean littoral of Israel, we used specific markers for in vivo and in vitro studies to expose the state of micronucleation; levels of defense transport systems such as membrane transport system of organic anions (SATOA) and organic cations (OCT); the state of the multi-xenobiotic resistance-mediating transporter (MXRtr). Based on fluorescent microscopy and microfluorometry, these markers offer powerful tools to expose cryptic changes in the affected populations and provide data necessary for planning and management to protect animal communities and preserve their biological diversity. Comparative analysis of general gene-expression in polluted and reference sites indicates that stress factors have differentially affected the various biological taxa and separated phenotypic sub-populations, producing a novel type of punctuated selection. Such factors, although negative in their influences, in some instances altering the qualities of organisms, and establishing alterations in their hereditary information, pre-adapt them to survive and succeed in new situations.     

Preliminary observations on the benthic macroinvertebrate communities of Ross Bay,a polluted area of lough leane,south-west Ireland

The physical, chemical and biological water quality characteristics of Ross Bay, monitored during the period July 1974–May 1975, are described. The benthic macroinvertebrate standing crop of the littoral zone was sampled quantitatively during July 1974. The results are described in terms of biomass distribution and the distribution of taxa. The sampling stations are placed in an ordinal series based on their respective pollutional status. Changes in community structure and taxonomic composition along the series are described in terms of species diversity and the distribution of “indicator” organisms. Based on this distribution, a scheme of biotic indices is devised in order to reduce complex community composition to simple numerical terms. For this purpose, individual organisms are given a water quality rating which is dependent on their relative tolerance or intolerance to pollution. Significant correlation is shown between the ordinal series, water quality, Diversity Index ($\text{d}\text{?}$) values, Community Similarity (τ) values and Biotic Quality (qb) values. The biological evaluation of water quality in lakes is discussed and it is suggested that the littoral benthos may serve in any future assessment of organic pollution and enrichment in Lough Leane.     

Ecological restoration of reclaimed wastewater lakes using submerged plants and zooplankton

High‐pollutant concentrations have led to the breakout of planktonic bloom and the breakdown of the ecosystem in many lakes in China and other countries. The removal of the organic and inorganic pollutants from industrial, agricultural and domestic wastewater and the restoration of the aquatic ecosystem of the polluted water bodies are persistent issues. Constructed wetlands are often used, and most depend on emerged plants. In this study, Daphnia magna, a type of zooplankton, and five species of submerged plants were used to remove nitrogen and phosphorus from reclaimed domestic wastewater in four scenery lakes of a garden in Peking, China. Water quality was assessed by the local environmental inspection station as the government inspection and a commercial company as the third party inspection, and the gathered data proved that ecological restoration was successful in this study.     

Microdistribution patterns of macroinvertebrate communities upstream and downstream of organic effluents

The present study analyses the distribution patterns of macroinvertebrate communities in four microhabitats (riffles, glides, leaf litter and bank roots) upstream and downstream of two waste water treatment plant (WWTP) effluents in northern Spain rivers. Macroinvertebrate communities were analysed in November 2006 by taking 5 samples from each of the microhabitats under unaffected (upstream WWTP) and affected (downstream WWTP) conditions, respectively. Water velocity, depth, substrate coarseness and hydraulic stress by means of the Froude number were also estimated at all sampling locations.Under unaffected conditions, the abundance and presence/absence of certain macroinvertebrate taxa were mainly determined by hydraulic characteristics (water velocity and Froude number) and feeding resource availability. However, neither macroinvertebrate richness nor abundance were neither significantly correlated with hydraulic stress nor substrate coarseness, although the number of macroinvertebrate taxa increased in microhabitats with high structural complexity. Macroinvertebrate abundance increased downstream of both WWTPs, while macroinvertebrate richness was not adversely affected by the organic enrichment of water. The structure and composition of macroinvertebrate communities occurring in riffles was similar under unaffected and affected conditions, while communities from leaf litter and submerged bank roots showed important changes above and below the WWTPs, indicating that they are probably the most appropriate communities for water quality assessment.     

Habitat quality–physicochemical water quality–littoral macroinvertebrate community nexus in Lugo Lake (Ethiopia): Priorities for sustainable water resources management

The integration of water quality characteristics with habplot-based habitat quality assessment score (HabQA) has received little attention in ecological quality assessment studies. This study investigated the macroinvertebrate community structure in relation with lake habitat quality and physicochemical water quality variables in Lugo Lake (Ethiopia). Twelve sampling sites (eight agricultural and four recreational) were included. The variation among macroinvertebrates data was significantly explained by HabQA score and soluble reactive phosphorus. The study revealed the greater importance of habitat quality characteristics in comparison with the other conventional physicochemical characteristics on macroinvertebrate community structure. We strongly recommend the use of HabQA system while studying macroinvertebrate community structure for a deeper understanding of the environmental functioning of tropical lakes. The results suggested the need to apply integrated and sustainable protection and management of the lake catchment (including wetlands) to enhance the ecological integrity and hence biodiversity of lakes.     

Indirect effects of contaminants in aquatic ecosystems

Contaminants such as petroleum hydrocarbons, heavy metals and pesticides can cause direct toxic effects when released into aquatic environments. Sensitive species may be impaired by sublethal effects or decimated by lethality, and this ecological alteration may initiate a trophic cascade or a release from competition that secondarily leads to responses in tolerant species. Contaminants may exert direct effects on keystone facilitator and foundation species, and contaminant-induced changes in nutrient and oxygen dynamics may alter ecosystem function. Thus, populations and communities in nature may be directly and/or indirectly affected by exposure to pollutants. While the direct effects of toxicants usually reduce organism abundance, indirect effects may lead to increased or decreased abundance. Here we review 150 papers that reference indirect toxicant effects in aquatic environments. Studies of accidental contaminant release, chronic contamination and experimental manipulations have identified indirect contaminant effects in pelagic and benthic communities caused by many types of pollutants. Contaminant-induced changes in behavior, competition and predation/grazing rate can alter species abundances or community composition, and enhance, mask or spuriously indicate direct contaminant effects. Trophic cascades were found in 60% of the manipulative studies and, most commonly, primary producers increased in abundance when grazers were selectively eliminated by contaminants. Competitive release may also be common, but is difficult to distinguish from trophic cascades because few experiments are designed to isolate the mechanism(s) causing indirect effects. Indirect contaminant effects may have profound implications in environments with strong trophic cascades such as the freshwater pelagic. In spite of their undesirable environmental influence, contaminants can be useful manipulative tools for the study of trophic and competitive interactions in natural communities.