Status Of Surface Waters Research Articles

A preliminary pressure–impact analysis applied in the Pinios river basin (Thessaly, Central Greece)

AbstractGreece has not yet undertaken one of the first and most important tasks required by the Water Framework Directive (WFD: the integrated review of the impact of human activity on the status of surface waters for each river basin – the IMPRESS analysis. Owing to the lack of a national methodology, a preliminary analysis was carried out for the Pinios river basin, applying a combination of different methodologies refined to suit the particularities of the Greek freshwater environment and to accommodate the limited availability of data. Pressures caused by the main pollution sources, point and nonpoint, were quantified in terms of pollution loads with the use of emission factors. The existing limited biological and physicochemical monitoring data were used to assess impacts. Additionally, we identified pressures caused by alterations from land‐use data; we carried out a River Habitat Survey (RHS) and estimated the hydromorphological impacts through the calculation of a Habitat Modification Score (HMS). Our results suggest that the probability of the Pinios river basin failing to achieve good ecological quality by 2015 due to pollution is high, and due to hydromorphological pressures is moderate.

Phytoplankton based assessment of the ecological status of four shallow lakes (Eastern Poland) according to Water Framework Directive – a comparison of approaches

The EU Water Framework Directive includes phytoplankton as one of the four biological elements to be used in the assessment of the ecological status of surface waters. In this work we establish the ecological status of four shallow lakes in the Polesie Region of Eastern Poland on the basis of phytoplankton and physicochemical data from the lake water. A number of recently developed phytoplankton indices, including the Carlson Index, Q index and German PSI were compared. Cyanoprokaryota, chlorophytes and dinophytes dominated in Lakes Głębokie and Sumin, while in the Lakes Rotcze and Maśluchowskie the biggest share belonged to Chlorophyta. On the basis of the Carlson Index, Lake Głębokie had the highest trophic score, while the lowest score was for Lake Rotcze. A similar result was also found with the Q index which indicated a good ecological state for Lake Rotcze ( Q =3.5), a bad state for Lake Głębokie ( Q =0.9), a poor status for Lake Sumin ( Q =1.2) and a moderate status for Lake Maśluchowskie ( Q =2.9). Similar results were obtained with the use of the German PSI which classified Lake Głębokie as bad status (PSI=4.7) and Lake Rotcze as good (PSI=2), although differences between the 2 indices appeared between the moderate and poor status lakes (respectively in the case of Lake Sumin – PSI=2.6 and Lake Maśluchowskie – PSI=4.4).

Assessment of the ecological status of European surface waters: a work in progress

The ‘normative definitions’ of ecological water quality classes given by the Water Framework Directive (WFD) are narrative descriptions of the conditions present in water bodies of different qualities relative to reference conditions found in unimpacted sites. In order to fill these descriptions with a more solid content, the definitions have been a subject of intensive development of quantitative methodologies for ecological status assessment as well as for rules and criteria for setting of reference conditions and ecological status boundaries for classification of water bodies. In this article, we recall the basic principles of the WFD that sometimes have been overlooked and point out some gaps remained and problems arisen during the ongoing implementation of the directive. Defining type-specific reference conditions for water bodies and finding biological metrics that sensitively reflect only the anthropogenic deviations from those conditions are the biggest challenges that the ecological status assessment faces. So far, there is no guarantee that reference conditions are comparable across EU Member States due to a lack of common criteria, which need still to be elaborated. Defining site-specific reference conditions instead of type specific is a novel approach that allows for minimizing uncertainties introduced by applying broad types. Search for new metrics has led to a real boom of multimetric indices which ought to be the adequate tool to measure the multiple human impairments but which should pass a thorough check before being included in monitoring programs. Curiously, some biological indices constructed as surrogates for chemistry (especially nutrients) start ‘living their own life’ and continue indicating the disturbance when the controlling factors change. This shows the obvious advantage of biological indicators against chemical ones. New challenges to WFD implementation are brought about by the need to consider the effects of alien species and climate change in the assessment framework, and by the nonlinear dose—response relationships dominating in biological systems. Attempts to diminish uncertainties in quality assessment have become a new labour-intensive field for researchers.

Prediction of Daphnid Survival after in Situ Exposure to Complex Mixtures

We applied a mechanistically based model to predict the effects of complex mixtures as occurring in the field on the survival of Daphnia magna. We validated the model by comparing predicted survival with observed survival of in situ exposed laboratory cultured daphnids to polluted surface waters, in which over 90 chemical contaminants were measured. Using the chemical composition of the surface water at each sampling site, we calculated whether or not any of the individual or shared no effect concentrations were exceeded. If they were, we calculated the effect on survival. In 34 out of 37 cases (92%) we correctly predicted daphnid survival in surface waters. In the case of mortality we could also appoint the compound or group of compounds causing the effect. It is concluded that the proposed mechanistically based model accurately predicts effects on daphnids in the field, given the chemical composition of the water. Hence it is a powerful tool to link the chemical and ecological status of surface waters.

Evaluating the usefulness of dynamic pollutant fate models for implementing the EU Water Framework Directive

The European Water Framework Directive (WFD) aims at achieving a good ecological and chemical status of surface waters in river basins by 2015. The chemical status is considered good if the Environmental Quality Standards (EQSs) are met for all substances listed on the priority list and eight additional specific emerging substances. To check compliance with these standards, the WFD requires the establishment of monitoring programmes. The minimum measuring frequency for priority substances is currently set at once per month. This can result in non-representative sampling and increased probability of misinterpretation of the surface water quality status. To assist in the classification of the water body, the combined use of monitoring data and pollutant fate models is recommended. More specifically, dynamic models are suggested, as possible exceedance of the quality standards can be predicted by such models. In the presented work, four realistic scenarios are designed and discussed to illustrate the usefulness of dynamic pollutant fate models for implementing the WFD. They comprise a combination of two priority substances and two rivers, representative for Western Europe.

Factors influencing changes in mercury concentrations in lake water and yellow perch (Perca flavescens) in Adirondack lakes

Over the past 20+ years, fish with elevated concentrations of mercury (Hg) have been observed in remote lake districts, including the Adirondack region of New York. Across eastern North America studies have also reported a negative correlation between fish Hg concentration and lake pH. Recent controls in emissions of sulfur dioxide (SO2) have resulted in some improvement in the acid–base status of acid-impacted surface waters including Adirondack lakes. In addition, there has been an apparent decrease in atmospheric Hg deposition. A synoptic survey of 25 lakes in the Adirondacks was conducted in 1992–1993 to analyze spatial patterns of Hg in the water column and yellow perch (Perca flavescens). The same cluster of 25 lakes was resurveyed in 2005–2006 to evaluate if changes in lake concentrations of Hg species or fish Hg have occurred. We observed a varied response of changes in water chemistry and fish Hg concentrations. In twelve of the resurveyed lakes the yellow perch had lower Hg concentrations, six lakes had yellow perch with higher Hg concentrations, and in seven lakes yellow perch Hg concentrations did not change significantly (α = 0.05). Four variables appear to influence the change in yellow perch Hg concentrations in the Adirondacks: watershed area, elevation, change in pH, and change in fish body condition. We hypothesize that as the acidity in lakes is attenuated, the lakes may become more productive and/or water quality conditions less stressful to fish leading to increasing fish body condition. As fish body condition improves, fish exhibit “growth dilution” of tissue contaminants leading to lower fish Hg concentrations.

Toward a holistic and risk‐based management of european river basins

The European Union Water Framework Directive (WFD) requires a good chemical and ecological status of European surface waters by 2015. Integrated, risk-based management of river basins is presumed to be an appropriate approach to achieve that goal. The approach of focusing on distinct hazardous substances in surface waters together with investment in best available technology for treatment of industrial and domestic effluents was successful in significantly reducing excessive contamination of several European river basins. The use of the concept of chemical status in the WFD is based on this experience and focuses on chemicals for which there is a general agreement that they should be phased out. However, the chemical status, based primarily on a list of 33 priority substances and 8 priority hazardous substances, considers only a small portion of possible toxicants and does not address all causes of ecotoxicological stress in general. Recommendations for further development of this concept are 1) to focus on river basin-specific toxicants, 2) to regularly update priority lists with a focus on emerging toxicants, 3) to consider state-of-the-art mixture toxicity concepts and bioavailability to link chemical and ecological status, and 4) to add a short list of priority effects and to develop environmental quality standards for these effects. The ecological status reflected by ecological quality ratios is a leading principle of the WFD. While on the European scale the improvement of hydromorphological conditions and control of eutrophication are crucial to achieve a good ecological status, on a local and regional scale managers have to deal with multiple pressures. On this scale, toxic pollution may play an important role. Strategic research is necessary 1) to identify dominant pressures, 2) to predict multistressor effects, 3) to develop stressor- and type-specific metrics of pressures, and 4) to better understand the ecology of recovery. The concept of reference conditions to define the ecological status is hard to apply and tends to ignore the fact that ecosystems can be highly dynamic. A better understanding of ecosystem responses to changes as well as early warning systems and concepts sensitive to various stressors to discriminate disturbances from natural variation are required. Because ecosystems are closely interconnected, an integrated monitoring, diagnosis, and stressors-based management of the whole water, sediment, groundwater, soil, and air system is required considering land use and the interaction with a changing climate. Extending this holistic approach beyond a consideration of existing pressures by anticipating on future ones to use and protect the aquatic environment in a sustainable way is one of the big challenges.

Setting the limits for engineered nanoparticles in European surface waters – are current approaches appropriate?

The current widespread and diverse use of engineered nanoparticles (ENPs) in consumer products is expected to result in direct and indirect emissions to the aquatic environment. In Europe, the Water Framework Directive (WFD) is responsible for maintaining a good chemical and ecological status of surface waters. This review provides an insight to the likely scenarios if an engineered nanoparticle should be considered a "priority substance" in the WFD. Through a brief literature review of the aquatic toxicity of carbon- and metal-containing ENPs and in light of principles to establish environmental quality standards, we conclude that it is impossible to set limit values for ENPs in surface waters now and in the foreseeable future. This is due to the extensive lack of knowledge not only in relation to unknown toxic effects, degradability, and bioaccumulation of ENPs in the aquatic environment, but also due to the questionable validity of test systems and methods to establish environmental quality standards (EQS). From this, we also suggest some paths to follow to compensate for these knowledge gaps which include environmental monitoring and a closer look at the use of ENPs in consumer products.

Assessing the stream water quality dynamics in connection with land use in agricultural catchments of different scales

The ecological status of many surface waters in the Czech Republic is poor, mainly due to still relatively high discharges of N substances especially from agriculture. High nitrate values in the streams situated particulary in basins of drinking water reservoirs invoke the neccesity for the precise detection of diffuse pollution areas to enable the setting of the appropriate land management strategies or relevant measures. We introduce a simple method for estimating the changes of nitrate concentrations in surface waters regarding the land use modification. Stream and drainage water nitrate concentrations in prevailingly agricultural catchments of three different scales located in the Crystalline complex of the Czech massif were included in this study. Water quality samples were collected through the years 1992–2006 at monthly and bi-monthly intervals. For the catchment land use analysis, the satellite images LANDSAT 7 (CORINE Land Cover) and digitised cadastre maps of the land register were processed using ESRI ArcMap GIS; both sources corrected by field survey. We demonstrate on three different basin – scale studies a strong relation between the arable land ratio within a catchment and the coherent stream water nitrate concentration. The results acquired from all the evaluated catchments showed that every 10% decrease of ploughed land proportion in a catchment lowers the nitrate concentration C90 value (90% probability of non-exceedance) in average by 6.38 mg/l.

Development of New Water Quality Model Using Fuzzy Logic System for Malaysia

Proper assessment of water quality status in a river system based on limited observations is an essential task for meeting the goals of environmental management. Various classification methods have been used for estimating the chang- ing status and usability of surface water in River basin. However, a discrepancy frequently arises from the lack of a clear distinction between each water utilization mode, the uncertainty in the quality criteria of water employed and vagueness or fuzziness embedded in the decision making output values. Owing to inherent imprecision, difficulties always exist in some conventional methologies like water quality index (WQI) when describing integrated water quality conditions with respect to various chemical constituents, biological aspects, nutrients, and aesthetic qualities. In recent years, the fuzzy logic based methods have demonstrated to be appropriated to address uncertainty and subjectivity in environmental issues. In the present study, a methodology based on fuzzy inference systems (FIS) to assess water quality is proposed. This pa- per presents a comparative study using fuzzy logic technique to assess status of river water quality by comparing the out- put generated by fuzzy with that of conventional methods. The model is based on observations made from Semenyih River in West Malaysia. The findings clearly indicate that the fuzzy inference system (FIS) may successfully harmonize inherent discrepancies and interpret complex conditions. This river water quality model can be extended to determine the non-regulated contaminants in water.

On the use of the partitioning approach to derive Environmental Quality Standards (EQS) for persistent organic pollutants (POPs) in sediments: A review of existing data

A review of experimental data has been performed to study the relationships between the concentration in water, pore water and sediments for different families of organic contaminants. The objective was to determine whether it is possible to set EQS for sediments from EQS defined for surface waters in the Daughter Directive of the European Parliament (COM (2006) 397). The analysis of experimental data showed that even though in some specific cases there is a coupling between water column and sediments, this coupling is rather the exception. Therefore it is not recommendable to use water column data to assess the chemical quality status of sediments and it is necessary to measure in both media. At the moment EQS have been defined for the water column and will assess only the compliance with good chemical status of surface waters. Since the sediment toxicity depends on the dissolved pore water concentration, the EQS developed for water could be applied to pore water (interstitial water); hence, there would be no need of developing another set of EQS. The partitioning approach has been proposed as a solution to calculate sediment EQS from water EQS, but the partitioning coefficient strongly depends on sediment characteristics and its use introduces an important uncertainty in the definition of sediment EQS. Therefore, the direct measurement of pore water concentration is regarded as a better option.

A metamodel based on MAGIC to predict the pre-industrial acidity status of surface waters

When assessing the acidification status for a body of water, a reference value that describes the natural state is often estimated. One way to define this reference is to use the biogeochemical model MAGIC. However, MAGIC requires too many input parameters and modelling skills to use for operational application at a regional scale where hundreds or thousands of objects need to be assessed. Here we explore the possibility of complementing MAGIC with a simpler metamodel. The metamodel, metaMAGIC, was calibrated to 95 lakes with pre-industrial ANC predicted by MAGIC. The lakes constituted a diverse population, spread across a region stretching 1360 km in a N-S direction. MetaMAGIC proved capable of estimating the pre-industrial ANC calculated by MAGIC with a validated median error of 13.2 μeq/L, using contemporary concentrations of base cations, SO42- and Cl- as predictors. In comparison with the commonly used SSWC-model, MetaMAGIC reproduces the pre-industrial buffering capacity reconstructed with MAGIC more accurately. An advantageous feature of the metamodel is that it allows the reference value to vary in response to short-term hydroclimatological influences. Hence it provides a more stable assessment when few contemporary measurements of water chemistry are available. This metamodelling approach is suggested as a useful tool for acidification assessment purposes, and more generally, for extending the information from complex biogeochemical models.

Preface: ‘Quantitative ecological responses for the Water Framework Directive related to eutrophication and acidification of European lakes’

This special issue of Aquatic Ecology presents most of the results on lakes from the EU FP6 project REBECCA, ‘‘Relationships between ecological and chemical status of surface waters’’, that were obtained during the project period 2004 to 2007. The REBECCA project has been funded by the EU Commission DG Research (Contract no. SSPI-CT2003-502158), and was also supported by national research funds and partner institutions. The objective of REBECCA has been to provide scientific support for the implementation of the EU Water Framework Directive (WFD) (EC 2000). Knowledge on relationships between the biological and physico-chemical properties of surface waters is a prerequisite for a successful implementation of the WFD, because dose-response relationships are needed to enable the management of catchments and to ensure that water bodies will achieve the ecological objective. This objective is defined as good ecological status for a given type of water body, and it is therefore essential to identify the boundary between good and moderate ecological status. More information about the REBECCA project is available at the project website: www.environment.fi/syke/rebecca. The production of papers for this Special issue of Aquatic Ecology started in May 2006 with a fruitful and pleasant workshop that took place in a beautiful, ancient monastery at the shore of Lago di Como in Varenna, Northern Italy, kindly organised by Gianni Tartari at IRSA, CNR, Italy. The spirit and enthusiasm created at this workshop, as well as the beautiful surroundings and inspiring discussions, have been the basis for the commitment of all authors to complete the articles included here. It is a great pleasure to see that our common efforts have now finally reached its goal. Most of the results presented in this Special issue of Aquatic Ecology were also discussed at the REBECCA final conference in Oslo, Norway, in May, 2007 that was organised by the Norwegian Institute for Water Research (NIVA) (Norway), Finnish Environment Institute (Finland) and the Centre for Ecology and Hydrology (UK). Since REBECCA has been a policy support project, dissemination of preliminary results to water managers has also been done during the project period at annual meetings, as deliverables available at the project website, as well as at the regular workshops of the ECOSTAT working group that is responsible for the WFD-required intercalibration of classification systems for assessment of ecological status in surface waters. The articles in this issue are, however, the only scientific publications of these results, providing A. Lyche Solheim (&) Norwegian Institute for Water Research, Oslo, Norway e-mail: anne.lyche@niva.no

Identification of benthic invertebrate and diatom indicator taxa that distinguish different stream types as well as degraded from reference conditions in Luxembourg

Abstract The main objective of the Water Framework Directive (WFD) is to achieve good ecological status for surface waters in Europe by 2015. The ecological status has to be defined based on near-natural reference conditions. Benthic invertebrates and diatoms are among the key biological elements recommended by the Directive to assess ecological quality of water bodies. The purpose of this study is to identify species associations of these biological elements that are characteristic of the different stream types occurring in Luxembourg and that distinguish degraded from reference conditions. In general, the results reveal that diatoms and invertebrates can be considered as complementary indicators with more diatom species being characteristic of small size stream types and more benthic invertebrate species being associated with larger stream types. Among invertebrates, Trichoptera, Hydrachnidia, Ephemeroptera and Diptera show high affinities for most stream types. Plecoptera, Oligochaeta appear as useful indicators for some particular types. If only reference sites are selected (all river types considered), the number of indicator species drops from 55 to 24 for diatoms and from 81 to 48 for benthic invertebrates. Moreover, for the larger stream type, no reference site was found at all. This trend is likely to be a consequence of the multiple anthropogenic pressures that have affected large parts of European lowland rivers for decades. Our results suggest that Trichoptera, Hydrachnidia, Diptera, Ephemeroptera and Oligochaeta could be considered as best candidate groups for a tiered-taxonomic resolution approach where only taxa which have narrow and specific ecological requirements would be identified to finer levels. In Central Europe, however, since taxonomic soundness and easy recognition are required, only Trichoptera and Ephemeroptera are the groups to be recommended at the present time.

Evaluation of the European Fish Index: false‐positive and false‐negative error rate to detect disturbance and consistency with alternative fish indices

Abstract An important requirement for meeting obligations under the European Water Framework Directive is the development of a fish‐based index that is able to predict the ecological status of surface waters, and particularly be able to distinguish between (nearly) pristine and disturbed conditions. The European Fish Index (EFI), based on the concept of the Index of Biological Integrity, was developed alongside alternative models such as the Spatially Based Method on a European level (SBM‐EU), for this purpose. A critical issue about these models is that they are simple to use but are able to predict whether a site is disturbed with a high degree of precision. From this perspective, two prediction errors need to be small: falsely declaring a site disturbed when it is not (false‐positive error; FP) and wrongly classifying a disturbed site as undisturbed (false‐negative error, FN). For the EFI, the overall FP rate was 22% and the FN rate was 19%. The performance was better for the SBM‐EU method with a smaller FP rate of 7% and an FN rate of 20%, but the EFI is preferred because, with only marginal loss of precision, it is far less complex. The EFI consists of a single model based on 10 fish metrics, while the SBM‐EU comprises 12 models covering 49 metrics. Comparison of the EFI with existing national or regional fish‐based assessment methods found major discrepancies that make intercalibration between these methods impractical.

Agriculture as a source of phosphorus causing eutrophication in Central and Eastern Europe

AbstractThere are considerable differences between the EU‐15 countries and Central and Eastern European (CEE) countries in the application rate of phosphorus (P) fertilizer and manure as well as in the climate and erosion patterns, but the eutrophication of surface waters is a common problem. The availability of information on the contribution of the CEE countries to European surveys on eutrophication is not adequate, because the amount of data available from these countries is small. There is thus a need to compile more comprehensive data sets for better assessment. Recent changes in agricultural practices, and their impact on the trophic status of surface waters in CEE countries, have been evaluated using a few selected pressure and state indicators (phosphorus balance, phosphorus status and erosion of agricultural land, P loss risk index, chlorophyll a, total and orthophosphate content of water) by compiling and analysing data from the literature. In the CEE countries, small annual P balances (−7 to +6 kg P ha−1) and declining levels of soil available P (proportion of soils adequately supplied with P dropped to between 10 and 50% of total area) may lead to low yields and economic difficulties. Only 11% of the variation in total phosphorus (TP) in rivers studied could be attributed to the calculated P loss risk index, and thus to the impact of differences in the agricultural diffuse source P load. The generation of more consistent data sets should be pursued for the whole of Europe in order to derive more powerful indicators. A refined P index could be one of the best indicators of eutrophication. Recent changes in the trophic level of surface waters could be attributed to a large extent to the change in point source P loads, i.e. to the diminishing amount of P load from municipal and industrial wastewater. The short‐term improvement of water quality in the CEE countries will require further improvements in wastewater treatment, but long‐term improvement will only be achieved by reducing diffuse P losses from agriculture, possibly involving changes in the land use pattern and in farming practices.

Real-time monitoring on Evrotas River (Laconia, Greece): dissolved oxygen as a critical parameter for environmental status classification and warning

The real-time water quality monitoring network of Evrotas River has been operational in Laconia since July 2004. The experience of more than a year of function has shown that dissolved oxygen is one of the most useful parameters monitored for warning and quality status classification. Concentration of dissolved oxygen in surface water is known to be a critical parameter for water quality and survival of organisms in it. At the same time, it provides an indication of the organic load in water, as well as the potential eutrophication. Dissolved oxygen in surface water normally depends on the atmosphere pressure and temperature that affect oxygen solubility. Real-time monitoring provides a very useful option through data processing that could not otherwise be implemented by conventional monitoring programs of any frequency. It is possible to monitor all daily variations of dissolved oxygen, replacing the unique value of one measurement in a conventional program, with a series of 144 measurements (every 10 min) regressing around a moving average value. This form of time series permits monitoring of the daily amplitude of dissolved oxygen fluctuation, which is an accessory indicator of the water quality status. This frequency permits dissolved oxygen to be utilized as a warning parameter, especially when industrial waste and sewage enters the river system. DO time series can be characteristic of surface water status quality in correspondence to the time series of water temperature. The graph of dissolved oxygen vs. temperature is proposed as a representative graph for overview of surface water quality status. The shapes of the plot concentrations are indicative of different conditions, and useful observations can be made at a glance.

A neural-fuzzy approach to classify the ecological status in surface waters

A methodology based on a hybrid approach that combines fuzzy inference systems and artificial neural networks has been used to classify ecological status in surface waters. This methodology has been proposed to deal efficiently with the non-linearity and highly subjective nature of variables involved in this serious problem. Ecological status has been assessed with biological, hydro-morphological, and physicochemical indicators. A data set collected from 378 sampling sites in the Ebro river basin has been used to train and validate the hybrid model. Up to 97.6% of sampling sites have been correctly classified with neural-fuzzy models. Such performance resulted very competitive when compared with other classification algorithms. With non-parametric classification–regression trees and probabilistic neural networks, the predictive capacities were 90.7% and 97.0%, respectively. The proposed methodology can support decision-makers in evaluation and classification of ecological status, as required by the EU Water Framework Directive.

Influence of copper mine on surface water quality

Aras water basin is located in northwest of Iran. Sungun mine which is the largest open-cast copper mine of Iran is located in this region and is in the primary stages of extraction. The influence of mining activity on the quality of regional surface water has been taken in to consideration in this study. Accordingly, sampling was done from 5 local streams in the study area. In order to consider the effect of flow quantity on the amount of different parameters, sampling was done in July and November 2005 when the local streams had the minimum and maximum flow rate respectively. The concentrations of major anions and cations as well as As, Mo, Al, Cu, Cd, Cr, Fe, Mn and Zn were determined. The results showed that the concentrations of metallic ions like aluminum, chromium, copper, manganese, molybdenum and iron in samples collected in July are above USEPA (Environmental Protection Agency) limits; however, mentioned concentrations are lessened remarkably in the samples collected in November. This fact is justified considering dilution of ions concentration via more amount of water in November. The chemical characteristics of water compositions on the basis of major ion concentrations were evaluated on a Schoeller and Piper diagram. Accordingly, the dominant type of water in July and November is considered to be Ca-HCO3 (calcium-bicarbonate type). Regarding Schoeller diagram, despite relatively high concentration of calcium, the current status of local surface water is acceptable for drinking purposes. By commencing mining excavation with designed capacity in near future, the minerals will come in to contact with air and water resulting in dissolution, especially in ponds, which, in turn, increases the concentration of heavy metals in surface water. Considering consequent uses of this water including drinking, irrigation, industrial, etc. precautions must be taken in to consideration.

Benthic diatom communities and their relationship to water chemistry in wetlands of central Italy

Diatoms are good environmental indicators and are often the main component of phytobenthos, one of the key groups of organisms recommended by the Water Framework Directive (W.F.D.) for the assessment of ecological status of surface waters. Although diatoms are regularly used as indicators in rivers and in lakes, less is known about the benthic diatom communities in wetland systems, especially in Italy. The main aim of the project was to provide a contribution to the knowledge on distribution, composition and structure of benthic diatom communities in wetland systems in Italy. In 2005, we investigated the benthic diatom communities and their relationships to water variables of nine ponds and wetlands along the Tyrrhenian coast near Rome. Furthermore, a first application of seven European diatom-based indices on this type of water body was undertaken. A total of 225 species and varieties belonging to 54 genera were identified. The Canonical Correspondence Analysis indicated that certain species were closely associated with each wetland type and their distribution mainly depended on nutrient and chloride contents: pollution tolerant species (i. e. Luticola goeppertiana, Mayamaea atomus, Navicula subminuscula) in the wetlands connected to river mouths, halophilous species and also marine littoral species (i. e. Nitzschia elegantula, Amphora coffeaeformis, Achnanthes brevipes var. intermedia, Epithemia adnata var. porcellus) in the coastal brackish ponds and wetlands, and less eutrophic species (i. e. Achnanthidium minutissimum, A. biasolettianum) in the lowland freshwater wetland. In general, the indices classified most of the studied water bodies as bad, poor and moderate status; few sites were classified into a good class, even for at least in one sampling occasion. Eutrophication and Pollution Index (EPI-D), Trophic Diatom Index (TDI), Taxa Pollution Tolerant (%PT), Pollution Sensitivity Index (IPS) and Generic Diatom Index (IDG) were significantly correlated to nutrient contents in the studied wetlands. Our preliminary data set illustrated the potential of the use of these benthic algae as bioindicators in wetlands.