Experiences from Ground, Coastal and Transitional Water Quality Monitoring

Microbial source tracking (MST) tools are used to identify sources of faecal pollution to accurately assess public health risks and implement best management practices. Many different viruses are excreted by humans and animals and are frequently detected in water contaminated with faeces or/and urine. Because of the large degree of host specificity of each virus and the substantial stability of many excreted viruses in the environment, some viral groups are considered to be accurate MST indicators. The Laboratory of Virus Contaminants of Water and Food at the University of Barcelona has proposed the use of viral indicators as well as cost-effective methods for the concentration of viruses from water. The developed procedures have been used to determine the levels of faecal pollution in environmental samples as well as for tracing the origin of faecal contamination. Such tools were recently used by the Catalan Water Agency to identify nitrate contamination sources in groundwater.

Human adenoviruses, human polyomavirus JC, porcine adenoviruses, bovine polyomaviruses, chicken/turkey parvoviruses, and ovine polyomaviruses can be quantified in samples using molecular methods (qPCR). The selected DNA viruses specifically infect their hosts and are persistently excreted in faeces and/or urine throughout the year in all geographical areas studied. The procedures that have been developed to quantify these viruses have been applied to bathing, coastal, surface and groundwater. In this study, the source of nitrate contamination in groundwater was identified by analysing viral markers, thereby demonstrating the usefulness of the selected viruses for the identification of sources of contamination in water. This methodology can be used to provide information to guide the proper application of measures in place to protect water from pollution caused by nitrates from several sources and thus to facilitate the accurate application of the 91/676/EEC Directive, which is mainly focused on agricultural sources of water contamination.

Currently, about half of the groundwater bodies in Catalonia present a bad status in terms of water quantity and chemical quality. The latter is linked to land use, since groundwater contamination originates from agricultural, industrial, and urban activities. This chapter reviews the monitoring programs performed in up to 18 groundwater bodies of Catalonia with the common objective of assessing the occurrence and fate of different polar organic contaminants (PolOPs) in the subsurface. They include the evaluation of polar pesticides and the veterinary antibiotics sulfonamides in rural areas and the study of pharmaceuticals, illicit drugs, and UV filters in urban areas. A review of the analytical methodologies used for the analysis of these compounds in groundwater has been provided, and PolOP concentrations measured have been discussed in terms of spatial and temporal variability and linked to potential contamination sources.

A GIS-based software platform was developed to arrange all the available hydrogeochemical data into a comprehensive structure and provide support for its proper storage, management, analysis and interpretation. This platform is composed of a geospatial database and a set of analytical instruments integrated in a graphical user interface that coordinates its activities with several software. The geospatial database was specifically developed to store and manage organic and inorganic chemical records, as well as other physical parameters. The analytical tools cover a great range of methodologies for querying, comparing and interpreting groundwater quality parameters. This tools enable us to obtain automatically several calculations such as charge balance error and ionic ratios as well as calculations of various common hydrogeochemical diagrams (e.g. Schöeller-Berkaloff, Piper, Stiff) to which the spatial components are added. Moreover, it allows performing a complete statistical analysis of the data (e.g. generation of correlation matrix and bivariate analysis). Finally, this platform allows handling relevant auxiliary information in an efficient way, and it is coupled to a number of technologies such as hydrogeochemical modelling or geostatistical analysis. The software platform was used in a case study involving several urban aquifers located into the metropolitan area of Barcelona (Spain) to illustrate its performance.

There are different vulnerability methods to evaluate groundwater potential pollution. One of them is the DRASTIC model, a well-known and widely used parametric method based in the analysis of seven hydrogeological factors. The applicability of the DRASTIC method was tested in the area of Catalonia, covering all territory (more than 31,000 km²). Available information related to groundwater characteristics was selected and taken from geological and hydrogeological cartographies, groundwater database, and bibliography. A cartography of 199 aquifers were used to group and to extrapolate the information when only spared data were available. Afterwards, data were processed in order to be adapted to the DRASTIC parameters. The outcome of the vulnerability map was a raster file with a 100 × 100 m pixel resolution. Two different coverages of vulnerability were calculated from different weightings according to the DRASTIC parameters: generic pollutants and pesticides. This analysis was made both in confined and non-confined aquifers. Resulting maps were considered very satisfactory, and they were compared with other existing vulnerability works in more local areas with high similar results. These vulnerability layers have constituted different groundwater management tools. In this project, we applied this approach in order to assess the risk of non-achievement of the Water Framework Directive’s (WFD) objectives for Catalan groundwater. Pressure and subsequent risk analyses were carried out from overlaying human activity areas with groundwater chemical data. For instance, nitrogen load from agriculture sources, contaminated soil areas, or sewage sludge application was overlaid with vulnerability map in order to obtain the global pressure.

The Water Framework Directive (WFD) mandates the use of biological quality element (BQE) phytoplankton to assess the ecological status of coastal and transitional water bodies (WB). Here, we present (i) a critique of the general ecological assumptions of the WFD, (ii) a review of the ecological features of coastal phytoplankton dynamics, (iii) several approaches to establish a methodology to assess water-quality along the Catalan coast (NW Mediterranean Sea) based on BQE phytoplankton, and (iv) a critical examination of the use of phytoplankton as a BQE. Since 2005, we have followed several approaches aimed at assessing water-quality based on BQE phytoplankton and linking this indicator to a proxy to a costal pressure index. We have therefore studied phytoplankton communities at three different levels: as potentially harmful species, as functional or taxonomic groups, and with respect to their bloom frequency. Despite intense efforts, none of these fulfilled the WFD’s management requirements, which in this context were found to contain several inherent flaws. As an alternative, we propose a methodology to assess water-quality based on the use of chlorophyll-a (Chl-a), as a proxy of phytoplankton biomass. The Chl-a concentration offers a very simple and representative measure of the phytoplankton community, and, importantly, it is used worldwide in water-quality studies, thus allowing not only regional but also cross-country comparisons. Moreover, because Chl-a concentrations clearly respond to nutrient enrichment, we were able to establish a BQE-specific typology for water bodies based on salinity, which is linked to nutrient loads. Using a newly developed coastal pressure index (Land Use Simplified Index, LUSI) that also reflects nutrient inputs, we demonstrated a significant pressure–impact relationship, as required by the WFD for management purposes. Based on this relationship, we were able to define reference conditions and water-quality boundaries for each type. We conclude our discussion with a consideration of the pros and cons of the use of phytoplankton as a BQE.

Seagrasses are flowering plants that inhabit coastal and transitional waters. They colonize sedimentary seabeds (and to a lesser extent rocky substrates) and present unique adaptations to the marine environment. Seagrasses are especially sensitive to environmental deterioration and live in a world that is particularly threatened by human activity. The response of the plants and their associated communities to disturbances is relatively well known. This has facilitated the development of a large number of seagrass bioindicators based on biochemical, physiological, morphological, structural, demographic, and community measures, especially after the deployment of the EU Water Framework Directive (WFD) and to a lesser extent the implementation of the Marine Strategy Framework Directive.

Bioindicators are at the interface between science and policy. In order for their use by managers for different purposes (monitoring, water quality assessment, long-term changes, etc.) to be robust and consistent, a clear definition of management goals is needed. The development of bioindicators must also be based on careful evaluation together with rigorous and transparent selection processes to ensure their scientific credibility.

Here, we present bioindicator indices based on seagrasses that were developed with the context of the implementation of the WFD in Catalonia, NE Spain, to assess the ecological status of coastal and transitional water bodies. Ecological status includes aspects concerning both the quality of the biological community and the hydrological and chemical characteristics of the environment. For this reason, and to develop a WFD-compliant system for ecological status assessment based on Mediterranean seagrasses, we used multivariate techniques to combine different bioindicators, gathered from different levels within the biological organization, into single biotic indices (POMI and CYMOX, based on the species Posidonia oceanica and Cymodocea nodosa, respectively). We report how this was achieved and how the robustness and reliability of those indices were assessed through correlation with human pressures, uncertainty analysis, and intercalibration. Finally, besides their applicability, we discuss their shortcomings and what we, as seagrass biologists, have learned overall from responding to the challenges posed by the WFD and specifically by the part dealing with seagrasses.

CARLIT is a Water Framework Directive-compliant methodology permitting a rapid assessment of water quality using rocky-shore macroalgae as biological quality elements. Here we present the water quality assessment of 32 coastal water bodies of Catalonia (Northwestern Mediterranean) during a period of 14 years (1999–2012) applying CARLIT. The averaged ecological status of the water bodies ranges between high and poor and the Ecological Quality Ratio shows a significant negative relationship with a modified LUSI index, thus providing further evidence on the utility of CARLIT to detect anthropogenic pressures. The lowest interannual variability in water quality was found in water bodies having most of their shore covered by natural rocks, while the highest variability was observed in water bodies situated in semi-confined environments or located close to freshwater discharges. In spite of the multiple advantages of CARLIT as a monitoring methodology, it can show strong disagreements in water quality assessment with other methodologies using other biological quality elements (i.e., macroinvertebrates). These discrepancies mainly occur in water bodies with reduced extension of rocky shores, questioning the use of CARLIT in these situations.

The Ecological Status (ES) of littoral coastal waters from Catalonia (Northwestern Mediterranean Sea) has been evaluated between 2002 and 2010 using MEDOCC (MEDiterranean OCCidental) index. Macroinvertebrate assemblages inhabiting both littoral fine sands (<20 m depth) and littoral sandy muds (25–35 m depth) have been sampled. The relative abundance of four Ecological Groups (e.g., sensitive, indifferent, tolerant, and opportunistic taxa) has been studied along a disturbance gradient. Sensitive taxa are often present in disturbed situations, and tolerant species are usually associated with the presence of opportunistic taxa, both in fine sands and muddy sediments. Sensitive species dominate in sandy habitats, while tolerant species dominate in muddy bottoms. The ES of Catalan coastal waters measured with the samples collected in littoral fine sands has improved since 2002, and all locations rated above a good ES in 2010. The ES measured with the samples collected in littoral sandy muds was above a good ES although the Ecological Quality Ratio (EQR) was always lower than in littoral fine sands. Consequently, the ES of all water bodies was rated as good or high ES in 2010, and no water body was at risk of noncompliance of Water Framework Directive (WFD) requirements.

The assessment of ecological quality in the frame of the Water Framework Directive has been performed in Ebre Delta bays (Alfacs and Fangar) using MEDOCC (MEDiterranean OCCidental) index. Results demonstrate the applicability of the index in heavily modified transitional water bodies and its response to pressures (mainly agricultural activities) affecting macroinvertebrate assemblages inhabiting soft bottoms. According to previous studies and the organic matter enrichment and heavy metal gradients inside the bays, three different Transitional Waters (TW) have been distinguished, but only two of them are assigned to Heavily Modified Water Bodies (HMWB). Two different reference conditions have been considered depending on the acting pressures: a Maximum Ecological Potential (MEP) for the areas highly affected by the pressures (i.e., HMWB) and a Reference Condition (RC) for non-modified waters from the southern shelf of Alfacs Bay where the effect of agricultural activity is scarce. A good Ecological Potential/Status (EP/ES) was always achieved in the surveys.

The Mediterranean Sea is especially prone to the introduction of alien species due to an intense marine traffic, the connection with the Red Sea through the Suez Canal and intensive aquaculture. Catalonia, a region in the Northwestern Mediterranean, began an extensive study on the presence, distribution and impact of invasive macroalgae in 1992, which was extended to all macrobenthic alien species by 2007. Gathering all presence and abundance data of introduced species from the monitoring, we also calculated a Biopollution Level (BPL) index to assess the magnitude of the effects of introduced species on the marine biota at a local level (water body) as required by Marine Strategy Framework Directive (MSFD). Seventeen alien species have been identified although only three can be considered so far as threatening in non-modified environments: the green alga Caulerpa cylindracea and the red algae Womersleyella setacea and Asparagopsis armata. These species show an uneven distribution along the coast but sometimes coexist in the same water body. The impact of alien species on native communities was never severe as shown by the low values obtained using the BPL. The only species triggering a moderate to strong impact was Caulerpa cylindracea but it only affected a single water body. However, C. cylindracea exhibited a great temporal variability on its abundance, with sudden collapses of its populations, which also caused a great variability in the BPL. Future monitoring of the coasts of Catalonia is advised as there is an increase in the number of water bodies affected by alien species and an increase in their abundances from 2007 to 2012.

In 2000 and from 2006 to 2011, a monitoring program was followed along the Catalan inner shelf, using homogeneous analytical methods and sampling strategies and focusing on the main sites of river sediment accumulation at present. Adjacent areas that are potentially vulnerable to pollution were also selected. Trace metals and organic pollutants were analyzed in surface sediment samples. Mean concentrations in each area show a distribution of organic and inorganic pollutants along the Catalan inner continental shelf. The highest concentrations are located on and around the coast of Barcelona city for most pollutants and locally on the coast of Tarragona city and the Ebre Delta for some of them. The concentrations tend to decrease gradually southward and sharply northward of Barcelona. The trace metal that shows the highest anomalies is Hg (max. enrichment factor, 34), whereas Cd, Zn, Cr, Pb, and Cu show more moderate anomalies. Sediment polycyclic aromatic hydrocarbons, 4-nonylphenols (metabolites of nonylphenol polyethoxylated, nonionic surfactant), polybrominated diphenyl ethers, polychlorinated biphenyls, and dichlorodiphenyltrichloroethane are also significant. The time evolution of most trace metals shows a decreasing trend mainly between 2000 and 2006, whereas between 2006 and 2011 trends of trace metals and organic pollutants are not clear, as some of them increased and others decreased and many of them peaked in 2007 and 2009. The greatest decreases in trace metals were in the most polluted areas.