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Water Quality in Ireland 2001-2003 - a summary of the EPA Report In many countries, reporting on water quality is probably the longest established accounting of environmental conditions, reflecting the importance of water resources and their susceptibility to pollution. The usual purposes of such reports are to describe the current position, as shown by the measurements made in the particular period covered and to highlight any trends apparent when comparisons are made with preceding periods. Of particular interest are any responses to recently introduced remedial measures or, indeed, to new or increased pressures generated by economic activities. On a more general note, water quality trends constitute one of the main environmental indicators used to assess progress towards sustainable development. The EPA report presents a review of water quality in the State in the years 2001-2003, based on measurements made in the period at some 3000 locations on 13,200 km of river and stream channel, on 492 lakes and 25 estuarine and coastal water areas and at some 300 groundwater sampling locations.
The report also presents an account of the work undertaken to date by the EPA, local authorities and other bodies to implement the Water Framework directive, adopted by the EU in 2000 and incorporated into Irish law in 2003.
WATER QUALITY OF RIVERS AND STREAMS National Situation The water quality situation in the 13,200 km of river and stream channel surveyed by the EPA, using a biological assessment method, is regarded as representative of the national status of such waters and to reflect any overall trends in conditions. Following the application of this method, the total river length surveyed in 2001-2003 has been apportioned to four biological Quality Classes. In terms of the estimated channel length in each class, the status of this national river baseline in the current and two preceding three-year periods was as follows: CLASS A (unpolluted)
CLASS B (slight pollution)
CLASS C (moderate pollution)
CLASS D (serious pollution)
Situation in the River Basin Districts In order of the proportion of surveyed channel length in Class A, the River Basin Districts (RBDs) identified under the national Regulations giving effect to the Water Framework directive, may be ranked as follows (1998-2000 period in parentheses):
As expected, the less densely populated and less developed regions have the higher proportions of unpolluted channel while the eastern and south-eastern areas are most affected by water quality degradation.
Changes since 1998-2000 The figures show that there was a slight reduction in the proportion of channel classed as unpolluted in the current compared to the previous period. This was due to a small increase in the slightly polluted category. In contrast, the proportion of moderately polluted channel has not changed between the two periods and there has been a reduction in the length of seriously polluted channel - which amounted to 76 km in 2001-2003, as compared with 112 km in 1998-2000 - and is the lowest on record since the early 1990s. At RBD level, recent improvements (increase in Class A) have been recorded in the North Western and South Western RBDs in contrast to an overall deterioration in the Shannon RBD. Serious pollution has been substantially reduced in the Eastern RBD and to a lesser extent in the South Eastern RBD while moderate pollution has been reduced somewhat in the Western RBD in recent years.
Suspected Causes of Pollution Of the 49 sampling locations classified as seriously polluted in the 2001-2003 period, 24 were suspected to be in this condition as a result of municipal, mostly sewage, discharges - this is four less than in the previous (1998-2000) survey period. The seriously polluted condition of a further seven locations was suspected to be due to agriculture, five to industry and the remaining 13 to miscellaneous or unknown sources. In regard to the moderate and slight pollution detected in the period, the bulk of this was suspected to be caused by municipal and agricultural sources in approximately equal measure.
Fish Kills The total number of fish-kills in freshwaters (rivers and lakes) reported by the Central Fishery Board (CFB) in the period under review was 147 - broadly similar to the previous period but still unacceptably high. It is likely that agriculture was responsible for some 48 of these fish kills, industry for 20 and sewage discharges for 17 - with the balance attributable to ‘other’ (47) and ‘unknown (15) causes.
Quality of Salmonid Waters Data for the rivers and streams designated under national Regulations as salmonid for the purposes of the EU Freshwater Fish directive are reviewed. These show a similar situation to previous periods, breaches of the water quality standards set by the Regulations being due mostly to exceedances for nitrite. As has been pointed out in previous reports, the limit set for this parameter seems too stringent as it is exceeded in many cases where the levels of other substances are within requirements. Other parameters breached include dissolved oxygen, ammonium and copper - but there were only a few instances of such breaches.
Impact of Selected Sewage Treatment Plants The performance of several sewage treatment plants upgraded in the early 1980s - as well as four newly upgraded plants - was assessed in the period, based on the conditions in the receiving waters. Serious pollution has been eliminated below most of these plants but restoration to fully satisfactory conditions has been observed in only a few cases - e.g. on the R. Liffey below the Osberstown treatment plant. It is likely that factors such as un-intercepted wastewater sources, plant overloading or under-performance and poor water quality upstream of the outfall are responsible for the failure to achieve such conditions in many cases; in addition, the absence of phosphorus removal facilities may allow eutrophic conditions to persist in some cases.
Nitrates While the recent data confirm that nitrate concentrations in Irish surface waters are generally well within the mandatory limit set for abstraction and drinking waters, the concentrations recorded - in the south-east particularly - are significantly above natural levels and, therefore, may contribute to eutrophication in both fresh and tidal waters. However, it is noted that the recently measured levels represent a continuance of the downward trend in concentrations which became apparent in the mid 1990s in the major rivers of the south-east.
Toxic Substances in Rivers and Streams The results of surveys of the levels of toxic and bioaccumulative substances (“Dangerous Substances”) in rivers, undertaken by the EPA in the period, are reviewed. These measurements included the substances specified in the Dangerous Substances Regulations of 2001. With the exception of trace concentrations of the herbicides simazine and atrazine, the synthetic organic compounds included in the survey were not present above the analytical detection levels.
Quality of Canal Waters While the major canals, based on the results of recent surveys, continue to have generally good water quality, they are nonetheless subject to some pressures. The majority of cases of canal enrichment or faecal contamination detected can be attributed, for the most part, to the incoming feeder streams. The monitoring programme of the canals and their feeder streams, carried out by the CFB for Waterways Ireland, has among its objectives the identification of sources of enrichment or microbiological contamination and to eliminate these where possible. The monitoring programme will have to be expanded to include biological elements, such as phytobenthos, macrophytes and fish in order to meet the needs of the Water Framework directive.
WATER QUALITY OF LAKES National Situation The main assessment of the water quality of lakes is based on estimates of the annual maxima of the chlorophyll concentrations. These are taken as indicators of the level of algal and cyanobacterial growth in the water column and thus of the tendency to eutrophication. In the 2001-2003 period, the great majority (82%) of the 492 lakes sampled were assessed as oligotrophic or mesotrophic - i.e. having low or moderate levels of algal and cyanobacterial production and they were deemed, therefore, to be of satisfactory water quality status.
Regional Situation On a regional basis, the proportion (91%) of lakes sampled in the western counties showing satisfactory water quality was much greater than in the case of the midlands (59%) and the remainder of the country (77%). Most of the lakes assessed as polluted in the period - including 10 of the 12 classified as hypertrophic - are located in the north midlands area. The bulk of the lakes in the State are located in three of the seven River Basin Districts identified for the purposes of the Water Framework directive - viz Western RBD, North Western IRBD and Shannon IRBD. The Western RBD had the highest proportion of lakes with a satisfactory status in the period but such lakes were in the majority in all of the RBDs.
Analysis by Size Most lakes in the State have areas less than 0.05 km2 and only 100 are greater than 1 km2. Of the 393 lakes surveyed in the period with areas less than 1 km2, 80 per cent were assessed as having satisfactory water quality while a larger proportion (89%) of the medium sized waters (1.0-7.5 km2) were similarly classified. Most (81%) again of the larger lakes (>7.5 km2) were assessed as satisfactory in the period - these including Loughs Corrib, Derg, Ree and Mask, the largest lakes in the State. However, in the case of Loughs Ree and Derg, it is likely that the recent infestation of these lakes by the Zebra mussel has been partially responsible for the much of the reduction of the chlorophyll concentrations recorded in recent years. In the case of the large western lakes, while the open waters showed low or moderate levels of planktonic algae, instances of excessive algal growth have been noted in the littoral areas and these may indicate some localised nutrient enrichment. Chlorophyll concentrations indicative of serious pollution were again recorded in four of the large lakes - viz Loughs Sheelin, Gowna, Ramor and Oughter - while in Lough Carrowmore in Co. Mayo, algal and cyanobacterial growths were indicative of a moderate degree of eutrophication.
Trends in Lake Water Quality The proportions of the surveyed lakes assessed as oligotrophic or mesotrophic have not changed appreciably since the mid 1990's, despite the increased coverage in recent years. However, there has been a marked increase in the area of lake water assessed as mesotrophic, due mainly to the change of the of the large Shannon lakes from the eutrophic to the lower trophic status.
Acid-Sensitive Waters Monitoring of the representative acid-sensitive lakes and their feeder streams in Co's Donegal (Lough Veagh), Galway (Lough Maumwee) and Wicklow (Glendalough Upper), continued in the report period and the results are presented. The biological and physico-chemical measurements continued to demonstrate the unimpacted status of the Donegal and Galway lakes, while the indications of artificial acidification in the water of the afforested feeder stream catchment at Glendalough were again clear. There is no indication of any change vis-ŕ-vis acidification in these lakes and streams over the last twenty years, but the levels of non-marine sulphate recorded have declined - reflecting a Europeanwide trend in response to controls on emissions of acidifying gases to the atmosphere.
Bathing Waters There are nine bathing water areas located on lakes which are designated for the purposes of the EU Bathing Waters directive. Monitoring showed that these were of good quality during the period - all complying with the directive’s mandatory standards in each of the three years and only one failing to match the more stringent guideline values set by the directive in 2001.
QUALITY OF TRANSITIONAL AND COASTAL WATERS National Situation The general assessment of water quality conditions of tidal waters reported was intended primarily to detect any tendencies to eutrophication and was based on the combined survey data for the 1999-2003 period. A total of 69 individual estuaries and coastal waters bodies in 25 estuarine and coastal areas were assessed in this period. Of these, 12 were classed as Eutrophic, three as Potentially Eutrophic, 28 as of Intermediate Status and 26 as Unpolluted. The eutrophic waters include all or part of the estuaries of the Broadmeadow in Co. Dublin, the Slaney in Co. Wexford and the Blackwater and Bandon in Co's Waterford and Cork. The designation of a further estuary, Argideen, in Co. Cork as eutrophic is tentative, as it is based solely on field observations of the growths of attached algae.
Data on nitrate and phosphate levels in the offshore waters of the Irish Sea arising from winter/spring surveys carried out by the Marine Institute, indicate that these are not artificially enhanced to any significant extent.
Toxic Contaminants in Estuarine and Coastal Waters Information on the levels of potentially toxic and bioaccumulative substances in tidal waters arises mainly from the monitoring of fish and shellfish tissue undertaken by the Marine Institute in connection with consumer protection requirements. Data for the 2001-2003 period continued to demonstrate the relatively low levels of such substances in samples taken in Irish waters which are well within those set for the purposes of consumer protection. Special surveys of the occurrence of the pesticide toxaphene and flame retardant chemicals were carried out in the period. Levels of the former in fish tissue were within recommended limits for consumers, while those of the latter substances found in fish and sediment, were at the lower end of the range reported for other European sites.
Quality of Shellfish and Shellfish Waters The monitoring of the sanitary status of shellfish from commercial production areas in the period, again showed that the majority of these sites fall into the category (B) of the official classification scheme - indicating the need for pre-purification before live molluscs are offered for sale. The sites receiving a C rating, thus necessitating re-laying of molluscs for at least two months in clean areas before offering for sale, was less than 5 per cent - similar to the position in previous periods. Monitoring of the quality of shellfish waters in 2001-2003, showed that physico-chemical conditions were good and complied with the requirements of the relevant EU directive. The occurrence of biotoxins in shellfish rearing waters continued to be monitored by the Marine Institute through the reporting period. This is based mainly on examination of phytoplankton samples for the presence of toxin producing algae - in particular, species of Dinoflagellates. DSP (Diarrhetic Shellfish Poisoning) was again the toxin most frequently detected, but a number of other toxins were recorded in the period. Several complete closures or restricted harvesting of shellfish areas were required in the period due to the presence of toxin-bearing algae, lasting up to 10 months in some cases.
Quality of Bathing Waters Monitoring of the quality of 122 bathing areas indicated that these were generally of satisfactory status - over 97 per cent of the sites being in compliance with mandatory standards set by the EU Bathing Waters directive and with national regulations in each year of the reporting period. In total, there were ten instances of annual data in non-compliance with the mandatory limits during the period, but none of the locations involved failed in more than one of the three years. There was some reduction of the number of sites attaining the more stringent guideline conditions set by the EU directive compared to the previous period - the proportion attaining these dropping from 92 per cent in 2000 to 84 per cent in 2003.
Radioactivity Monitoring The measurements of radioactivity in the marine environment carried out by the Radiological Protection Institute of Ireland are mainly intended to assess the impact of the discharges to the eastern Irish Sea from the Sellafield nuclear reprocessing facility in north-west England. The main artificial radionuclide of concern in these discharges - caesium-137 - has remained at a relatively stable level in the Irish marine environment since the mid 1990s - these levels being considerably lower than those measured in the preceding decades. Caesium-137 continues to be the largest contributor to the total intake of artificial radionuclide via the consumption of fish and shellfish taken from Irish Sea waters. Discharges of technetium-99 from the Sellafield facility have increased in recent years, but, as this isotope has a relatively low radiotoxicity, it contributes only a minor fraction of the total intake of artificial radionuclide through the consumption of seafood. The currently estimated radiation dosage to heavy consumers of such food is, however, only a very small proportion (<0.05%) of the total annual dosage received from all sources.
Oil Pollution Incidents The documentation and investigation of oil pollution in the marine environment is the responsibility of the Irish Coast Guard, whose remit covers an area stretching to 200 miles off the west coast and to the median line between Ireland and the UK in the Irish and Celtic Seas. Anti-pollution measures were successfully deployed in the period in most cases of vessel grounding or similar incident. In addition, 148 reports of pollution were investigated. Mineral oils accounted for the bulk of the polluting material observed but, in most cases, it was not possible to identify of the vessels involved. The position, in this respect, may be improved in future by the use of aerial surveillance.
QUALITY OF GROUNDWATERS National Situation Since many groundwaters are used directly - without treatment - for potable supply, it is considered appropriate that their quality should be assessed in relation to the requirements for such water set out in the EU Drinking Water directive and corresponding national regulations. The data obtained from the measurements made in the 2001-2003 period - at some 300 locations representative of the main aquifers and abstraction points - show again that the groundwater quality at the majority of locations was in conformance with these requirements at the times of sampling. However, a significant number of instances of exceedances of the limits - including those for faecal coliforms - were recorded and suggest that protection of these waters is not effective in some cases. A comparison of the 2001-2003 data with those for the 1995-1997 and 1998-2000 periods, shows only minor changes for most parameters measured, although there has been a reduction in the level of faecal coliform contamination.
pH and Conductivity Most samples showed values within the normal range for these parameters, which are generally reflective of natural characteristics. However, 51 samples had pH values less than 6.0 - the most acidic having a pH of 4.8. Relatively high conductivity (>1000 µS/cm) was recorded in 41 samples, of which 15 exceeded 1500 µS/cm - the Maximum Acceptable Concentration (MAC) for drinking water.
Ammonia Appreciable concentrations of ammonia in groundwater are indicative of contamination with organic waste and thus of the potential presence, inter alia, of sewage derived material. Some 6 per cent of the samples taken had ammonia concentrations over 0.23 mg/l N, the drinking water MAC - the highest concentration recorded being 30 mg/l N. Mean concentrations over 0.23 mg/l N were recorded at 20 of the 302 locations assessed for ammonia contamination. The data showed only minor differences when compared to those for the previous reporting periods.
Nitrate The presence of high nitrate concentrations in groundwaters is of public health concern if these are used for potable supply and, in addition, may contribute to surface water eutrophication at times when these waters contribute the bulk of the flow in rivers and streams. More than one fifth of the samples analysed for nitrate had concentrations over the guide level (25 mg/l NO3) for drinking wate, while in 34 samples, the nitrate concentration exceeded the mandatory limit of 50 mg/l NO3. Mean concentrations exceeded the guide level at 70 of the 301 sampling stations assessed and exceeded the mandatory limit at five of these locations. Again, only minor changes were recorded compared to the results for the earlier reporting periods.
Chloride Chloride levels in freshwaters are largely determined by the amount of sea-derived salts entrained in precipitation. However, the presence of organic wastes such as sewage may significantly increase the chloride content of waters and, if high enough, these may impart a taste. The drinking water MAC for chloride is 250 mg/l and this was not exceeded in any of the groundwater samples taken in the period. Most (85%) of the sampling locations had mean concentrations less than 30 mg/l. There were no significant differences to results from the earlier periods.
Phosphate The main implication of above natural levels of phosphate in groundwaters is the potential to contribute to eutrophication in associated rivers and lakes. The MAC for drinking water set by the 1988 directive is around 2.2 mg/l P - a level well above the concentrations typical of surface waters. However, a limit for phosphate is not specified in the revised directive of 2000 which took effect in 2004. Mean phosphate concentrations exceeded 0.03 mg/l P - the limit set for the annual median concentration in rivers under the Phosphorus Regulations - at 94 of the 303 sampling locations assessed, while this concentration was exceeded in 27 per cent of the samples analysed. The proportion of locations with raised concentrations of phosphate was greater than in the preceding reporting periods.
Iron and Managnese High concentrations of these naturally occurring elements may cause tastes and the staining of fabrics during washing. Organic pollution of groundwaters can exacerbate this effect by producing the reducing conditions which lead to the formation of the soluble ions of the metals. MACs of 0.2 mg/l Fe and 0.05 mg/l Mn have been set by the drinking water directive. Mean concentrations of iron and manganese, respectively, exceeded the MACs at 16 and 17 per cent of the sampling locations in the 2001-2003 period - the highest concentrations recorded in individual samples being 7.9 mg/l Fe and 4.6 mg/l Mn. A continuing reduction in the proportion of sampling locations having mean concentrations over the MAC has been noted in the case of both metals over the three reporting periods.
Bacteriological Examination The main threat to users of groundwaters is contamination with pathogenic microorganisms - such as Salmonella originating in sewage, animal manures or other organic wastes. The potential presence of such agents is usually inferred from the level of contamination of waters with bacteria of faecal origin, in particular faecal coliforms. Thus, the drinking water directive requires that these be undetectable in samples. In the period under review, faecal coliforms were detected in 22 per cent of the samples of groundwater taken and at 49 per cent of the sampling locations. In 12 per cent of samples, counts of faecal coliforms exceeded 10/100 ml - a level indicating gross contamination. While these figures indicate that a significant level of faecal contamination of groundwaters persists, it is noted that the 2001-2003 data indicate a significant reduction of the incidence of such contamination compared to the earlier periods.
Uranium Following the detection of uranium in some groundwater samples taken by the EPA in 2001, it was decided to conduct a more systematic survey of its occurrence in these waters in the current reporting period. Of the 1228 samples analysed, 80 per cent had concentrations less than the detection level of 1 µg/l, while only 24 had concentrations over 10 µg/l. The highest concentration recorded was 132 µg/l in a sample from Co. Wicklow. These results may be compared with a tentative guideline limit of 15 µg/l for drinking waters proposed by the World Health Organisation. High levels of uranium may have a toxic effect on the kidneys. While an investigation by the Health Services Executive found no evidence of kidney disease associated with the use of water from the Wicklow source, some changes in the sourcing of water supplies were made as a result of the findings.
IMPLEMENTATION OF THE WATER FRAMEWORK DIRECTIVE The directive establishing a framework for Community action in the field of water policy - commonly known as the Water Framework directive (WFD) - was formally adopted by the EU Parliament and Council in October 2000 and incorporated into Irish law by Regulation in December 2003. The directive establishes a comprehensive basis for the management of water resources in the Member States and provides for the repeal of a number of existing directives dealing with water quality. The new directive requires the establishing of River Basin Districts (RBDs) as the units for water resource management. The primary role for RBDs is the formulation of management plans incorporating those measures required to meet the objectives of the directive - including the attainment of good quality for all waters by 2015. Good quality in the context of the directive means only minor change of the physical, chemical and biological characteristics of water bodies compared to the natural state and this is a more comprehensive requirement than that of existing directives, which deal mainly with water quality.
The Regulations identify four RBDs wholly within the State (Eastern, South-Eastern, South-Western and Western) and three International RBDs shared with N. Ireland (Shannon, North-Western and Neagh-Bann). Implementation at RBD level is being undertaken by the local authorities with the assistance of consultants. Special arrangements have been made with the NI authorities to undertake the implementation in the three IRBDs. A national steering committee was convened by the Department of the Environment, Heritage and Local Government in 2001 to oversee the implementation of the directive. In January 2004, the EPA convened a Technical Co-ordination Group to deal with this at a more detailed level - a number of Working Groups have been established under the former to investigate and make proposals on specific matters. The main task, undertaken to date, was the preparation of the Characterisation Reports for the RBDs. This involved the documentation of the physical, chemical and biological features of the surface and groundwaters and an assessment of the pressures acting on them due to human activity. For the surface waters, this included the discrimination of the different physical types present having biological significance and the reference or high quality conditions for these types. Groundwaters were characterised on the basis of physical and chemical features. Water bodies subject to major physical alterations were identified - these will be candidates for designation as heavily modified water bodies in which appropriate objectives will apply. The data on pressures were used to assess the risk of water bodies not achieving the objectives of the directive. Pressures in this context include - in addition to those with a potential to cause pollution - physical impacts on the morphology of the water body, presence of alien species and fishing pressure. Almost two thirds of river and larger lakes water bodies and a similar proportion of groundwater bodies were assessed as at such risk - with lower proportions in the case of transitional (estuarine) (~50%) and coastal (27%) water bodies. In most cases, the ‘at risk’ status was assigned on the basis of morphological factors or diffuse sources of pollution.
The next main task following will be the consideration of the measures needed to meet the objectives of the directive in those water bodies not achieving or at risk of not achieving good status.
CONCLUSIONS The data and other information available for the 2001-2003 period indicate that:
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