Member State report / Art8 / 2012 / D9 / Ireland / NE Atlantic: Celtic Seas

Report type Member State report to Commission
MSFD Article Art. 8 Initial assessment (and Art. 17 updates)
Report due 2012-10-15
GES Descriptor D9 Contaminants in seafood
Member State Ireland
Region/subregion NE Atlantic: Celtic Seas
Reported by Department of the Environment, Community and Local Government
Report date 15/04/2013
Report access ACSIE_MSFD8bPressures_20130415.xml

Irish Assesment Area

GES component
Feature
LevelPressureBathingLower
LevelPressureBathingHigher
LevelPressureShellfishLower
LevelPressureShellfishHigher
LevelPressureOther
ImpactPressureShellfish
Assessment Topic
MicrobialPathogensBathingWater
MicrobialPathogensShellfishWater
MicrobialPathogensOther
MicrobialPathogensImpactShellfishWater
Element
Element 2
ThresholdValue
Threshold value/Value unit
Proportion threshold value
Status of criteria/indicator
OtherStatus
OtherStatus
NotAssessed
NotAssessed
Status trend
Stable
Unknown_NotAssessed
Unknown_NotAssessed
Unknown_NotAssessed
Status confidence
High
Low
NotRelevant
NotRelevant
Description (status of criteria/indicator)
Over the past 10 years the quality of bathing water in Ireland has remained high, with the majority meeting required EU standards. Monitoring results indicate that there is little risk to bathers’ health from pollution in designated bathing areas of Ireland (EPA, 2012 p. 123)
The SWD has a guide value but no mandatory levels. This makes it difficult to judge the pressure status. However, occasionally illness outbreaks associated with the consumption of virus contaminated bivalve shellfish have been reported. Therefore microbial pathogens are presently considered to be a significant pressure in bivalve shellfish waters (pers. comm. Marine Institute).
N/A
N/A
Limitations
The magnitude and distribution of microbiological contamination in the marine environment is variable and can be strongly influenced by weather (amount of rainfall), climate (temperature, intensity of light) and environmental conditions (turbidity and amount of organic matter) (OSPAR, 2009 p. 9). Such variability should be carefully considered when evaluating temporal differences in microbial occurrence. The assessment of microbial pathogens in Irish waters is based on bathing water and shellfish water monitoring which is only representative of microbial pathogen populations in near-shore waters. Microbial pathogen populations for open (marine) waters are not assessed by monitoring programmes and so it is not known to what extent offshore microbial pathogens population impact near-shore waters. Although it is probable near-shore water quality is primarily influenced by land-based activities, it is important to understand the contribution of offshore marine-based activities also. The introduction of new assessment parameters and the adoption of the revised bathing water classification (either ‘excellent’, ‘good’, ‘sufficient’ or ‘poor’) from 2015 is likely to result in a realignment of compliance standards. The standards set for reaching the status of ‘excellent’, for example, are approximately twice as stringent as the current ‘guide values’, which are presently used as a basis for the awarding of Blue Flags to beaches. The introduction of the new Bathing Water Quality Regulations is therefore likely to result in some decrease in Ireland’s current high level of compliance, and some popular bathing areas may subsequently fail to meet ‘sufficient’ status without improvements in wastewater infrastructure. The categorical information presented is based on the proportion of assessed Bathing Waters not meeting lower limit and higher limit values between the period 05/2011-09/2011.
Bacteriological levels in shellfish flesh may fluctuate significantly because of possible annual and seasonal climatic variation. Individual one-off pollution events may also significantly affect bacterial levels in shellfish. It is therefore important that the success of future actions taken under the pollution reduction plan for a particular area is not judged on an apparent bacteriological water quality improvement compared with the previous year’s bacteriological data. Such an apparent improvement may simply be due to natural variation. As a result compliance with the bacteriological guide values should be assessed over a period of time which will take account of such variation (Marine Institute, 2010 p. 10). Microbiological pollution in marine waters is variable and dependent on the weather (amount of rainfall), climate (temperature, intensity of light) and environmental conditions (turbidity and amount of organic matter) (OSPAR, 2009 p. 9). The assessment of microbial pathogens in Irish waters is based on bathing water and shellfish water monitoring which is only representative of microbial pathogen populations in near-shore waters. Microbial pathogen populations for open (marine) waters are not assessed by monitoring programmes and so it is not known to what extent offshore microbial pathogens population impact near-shore waters. Although it is probable near-shore water quality is primarily influenced by land-based activities, it is important to understand the contribution of offshore marine-based activities also. The categorical information presented is based on the proportion of assessed Shellfish Waters not meeting lower limit values between the period 02/2009-11/2011. There are no higher limit values set by the Shellfish Waters Directive for microbial pathogens.
N/A
N/A
Assessment period
Description
In the 2011 bathing season, the presence of intestinal enterococci and Escherichia coli were assessed for compliance with the water quality standards specified in the Bathing Waters Directive 76/160/EEC. The occurrence of both intestinal enterococci and Escherichia coli in bathing waters are indicative of faecal contamination and, although not technically considered to be pathogenic, they do share the introduction and distribution pathways of pathogenic bacteria of faecal origin (Prüss 1998 cited in WHO, 2004 p. 53) and this therefore implies a strong probability that harmful bacteria may be present. Intestinal enterococci are usually present in lower numbers than Escherichia coli but are able to survive longer than Escherichia coli providing a more durable indicator of pollution (EPA, 2007 p.15). The overall quality of Ireland’s bathing water is high with 98.4% of identified coastal bathing waters meeting the mandatory standards and classified as being of ‘sufficient’ water quality status in both 2010 and 2011. Meanwhile, 84.1% of bathing waters met the higher guideline standard and were classified as being of ‘good’ status in 2011. This is lower than the previous year when 92.6% of bathing waters met these standards. However, 2011 was the first year of the implementation of transitional arrangements for the assessment of bathing water quality and changes in microbiological parameters, combined with unfavourable summer weather conditions, may have contributed to a drop in the numbers of waters achieving ‘good’ status. Of the 14.3% of bathing waters that met the mandatory standard but failed to meet the guideline values, most were associated with two geographically distinct areas, one to the east and the other to the west of Ireland (EPA, 2012 b). A total of two bathing waters or 1.6% failed to comply with the minimum mandatory standards and were classified as having poor quality status. These were both located on Ireland’s west coast, with one recording a recurring failure since 2005 being primarily due to nearby sewage works discharge. A programme of remedial works for the nearby wastewater treatment plant which has recently been licensed should bring about significant improvements in water quality in the near future. In the case of the other bathing water, the classification resulted from an uncharacteristically poor sample result taken after bad weather (EPA, 2012 b). From 2001 to 2011, overall compliance was relatively stable although some year-to-year variation is evident. Compliance with at least the mandatory standard remained ≥93% throughout the assessment period while compliance with the guide standards remained ≥80%. It is likely the year-to-year variation is influenced by factors such as weather, climate and environmental conditions (e.g. turbidity and amount of organic matter) (OSPAR, 2009 p. 9). Although this report discusses bathing water results from 2001 to 2011, preliminary results from the 2012 bathing season has shown that the numbers of beaches achieving good status has dropped by 22 to just 90 (from 112). There is clear evidence of weather impacts from rainfall which saw the south-west of the country experience rainfall of 2-3 times the normal summer 30yr average making it the wettest summer in some areas for more than 50 years. This resulted in extensive low level contamination (mainly Escherichia coli) exceeding guide values. Some extreme instances of elevated bacterial populations greater than mandatory values were associated with very heavy rainfall events (pers. comm. EPA).
In 2011 the levels of Escherichia coli in designated shellfish waters were monitored and assessed for compliance with the water quality standards specified in the EU Shellfish Waters Directive. The occurrence of Escherichia coli in shellfish waters is indicative of faecal contamination and, although not generally considered to be pathogenic, they do share the introduction and distribution pathways of pathogenic bacteria and viruses of faecal origin (Prüss 1998 cited in WHO, 2004 p. 53) and this therefore implies a strong probability that harmful bacteria may be present. Of the sixty-three designated shellfish waters in Ireland 65.1% achieved the guideline standard for Escherichia coli in shellfish flesh from 2009 to 2011. Due to lack of data it was not possible to make an overall assessment of compliance with the guideline standard of four designated areas (Marine Institute, 2012 p. 9). Year to year variation in the overall level of compliance at the designated sites was observed. This variation is thought to be due partly to the fact that only a small number of results contribute to the assessment (four, taken quarterly) and partly due to variability in environmental factors (e.g. rainfall) (Marine Institute, 2010 p. 10). In general, very little information exists on the trends in shellfish water quality, with very limited data available (OSPAR, 2009 p. 13). In Ireland, with data from only three years monitoring available, the ability to determine temporal trends in shellfish water quality is not possible for this round of reporting
Exposure to contaminated seawater indicated by high levels of intestinal enterococci and Escherichia coli can have adverse effects on human health, including gastrointestinal and respiratory diseases. The health risk is dependent on the infectious dose and the human sensibility to microbial pathogens (age- or immunity-dependant). Some pathogens cause significant health impacts in humans even at low concentrations (e.g. hepatitis A virus, Escherichia coli O157:H7, Vibrio cholerae), while others need to be ingested in high concentrations to be harmful (e.g. Vibrio parahaemolyticus) (OSPAR, 2009 p. 9). Human exposure to pathogens in the aquatic environment during recreational activities may result in diseases. Susceptible populations (younger, immune deficient or older populations) may have a higher risk of contracting severe illnesses. A link between gastroenteritis, acute febrile respiratory illness, ear infections and a range of minor illnesses and faecal-contaminated bathing waters has been clearly demonstrated in reviews provided by the World Health Organisation (WHO). In the majority of cases the primary disease symptoms are diarrhoea, vomiting and acute respiratory infections) (OSPAR, 2009 p. 9). Infectious diseases have also been linked to the consumption of raw shellfish such as oysters, mussels, cockles and clams. Bacterial diseases such as cholera and typhoid fever were the first to be suspected of being associated with the consumption of microbiologically contaminated shellfish. Viral outbreaks believed to be linked to contaminated shellfish consumption were first reported over 50 years ago. Initially, the analysis of outbreaks was mainly based on epidemiological data and symptoms in patients (Richards, 1987). The development of molecular biology techniques to detect low levels of enteric viruses in shellfish has provided more accurate methods for the detection of disease transmission by shellfish. Although many enteric viruses can be detected in human faeces, only hepatitis A virus (HAV) and norovirus (NoV) have been clearly identified as infectious agents in consumed shellfish that are regularly associated with human illness (OSPAR, 2009 p. 10). In Europe the most common illnesses associated with bivalve mollusc consumption are gastroenteritis (NoV, Salmonella, Vibrio paraemolyticus) and hepatitis caused by hepatitis A virus (HAV). Although a cause of illness in the past Salmonella is now rarely associated with bivalve consumption. Other gastroenteric viruses, (astroviruses and parvoviruses), parasites such as Crypstosporidium and bacteria (Escherichia coli O157:H7, Shigella, Plesiomonas, Listeria) have occasionally been detected in shellfish or in shellfish related outbreaks although the significance of their presence as a reflection of water quality is unclear (OSPAR, 2009 p. 9).
Input load
Item525
Item15
Unknown_NotAssessed
Item2550
Unknown_NotAssessed
Load unit
100 Escherichia coli cfu/100ml; 100 intestinal enterococci cfu/100ml
2000 Escherichia coli cfu/100ml; no mandatory standard for intestinal enterococci
≤230 Escherichia coli MPN 100g-1 flesh
Not Applicable
Confidence
High
Low
Non related GES component
Trends (recent)
Stable
Unknown_NotAssessed
Unknown_NotAssessed
Trends (future)
Be stable
Unknown_NotAssessed
Unknown_NotAssessed
Description (activities)
The principal activities contributing to the pressure in the marine environment are discharges from municipal wastewater treatment works and run-off from agricultural lands. Wastewater from unsewered properties and sewage network failures have also been identified as contributing to levels of microbial pathogens in the marine environment. Sewage discharges including sewage outfall from wastewater treatment plants, combined sewer overflows and storm water discharges can contain high levels of microbial pathogens. These discharges will subsequently affect the levels of microbial pathogens in receiving waters. The type of treatment applied to wastewaters plays an important role in the microbiological load discharged into marine waters (physical, biological or tertiary treatments) (OSPAR, 2009 p. 7) as the discharge of inadequately treated effluents can affect the levels of microbial pathogens in receiving waters (Shannon RBD, 2010 p. 11). Combined sewer overflows receive rainfall water, untreated wastewater and runoff during high precipitation events – all sources of faecal contamination – and can seriously impact bathing waters or shellfish areas (Lequette et al., 2006). Heavy rainfall will cause a rapid flushing through sewerage systems which can overload sewerage infrastructure (OSPAR, 2009 p. 8), and the resulting intermittent discharges have been identified as one of the major sources of shellfish contamination (Lee et al., 2003) Sewage network failures, in contrast to capacity overloading, are also a potential source of pollution. Sudden or prolonged storm events could contribute to this pollution and could trigger faecal contamination even during dry weather (OSPAR, 2009 p.7-8). Leaking from defective underground pipes or seepage from containment areas can lead to the microbiological contamination of bathing and shellfish waters (Shannon RBD, 2010 p. 11).On site wastewater treatment plants also pose a risk to surface water from microbial pathogens. Factors which may lead to these systems transferring contaminants to surface waters include: inadequate percolation in the catchment, whether suitable types of systems are selected, whether they are installed and maintained to appropriate standards, and whether they are situated close to bathing waters, designated shellfish areas, or to ditches, drains, watercourses, wells or boreholes. Monitoring indicates faecal contamination in some shellfish areas around Ireland’s coast could be arising from this source (e.g. DEHLG, 2009(a) p. 72). Approximately 64% of Ireland’s total land area is used for Agriculture (www.teagasc.ie) and the associated animal slurry, manure and silage is a common source of organic pollution and a likely source of faecal contamination in estuarine and coastal waters. The potential risk of harmful contamination from agricultural runoff will depend on factors such as soil type and slope of the land (e.g. DEHLG, 2009(b) p. 69). Discharges from marine based industry (e.g. shipping, leisure activities such as boating) may also cause high levels of microbial pathogens in the marine environment (OSPAR 2009 p.7). Inappropriately managed aquaculture activities can contribute to raised levels of microbial pathogens in marine waters by causing increasing the concentration of organic contamination around finfish cages (Shannon RBD, 2010 p.11). Proximity to ports, marinas and other coastal facilities is another possible source of microbiological contamination, with activities associated with boat movements in the vicinity of shellfish areas suggested as a potential source of faecal contamination in some of Ireland’s designated shellfish areas (DEHLG, 2009(c) p. 74). It is evident that land-based and marine-based activity can contribute to levels of microbial pathogens in the marine environment and thus pose potential health risks to humans. However, humans themselves also represent a source of faecal contamination in recreational waters. The WHO (1999) identified bather contamination as one of the most important sources of human faecal contamination in bathing waters. Other sources such as wild animals may also contribute to levels of microbial pathogens in the marine environment (OSPAR 2007 p.7).
The principal activities contributing to the pressure in the marine environment are discharges from municipal wastewater treatment works and run-off from agricultural lands. Wastewater from unsewered properties and sewage network failures have also been identified as contributing to levels of microbial pathogens in the marine environment. Sewage discharges including sewage outfall from wastewater treatment plants, combined sewer overflows and storm water discharges can contain high levels of microbial pathogens. These discharges will subsequently affect the levels of microbial pathogens in receiving waters. The type of treatment applied to wastewaters plays an important role in the microbiological load discharged into marine waters (physical, biological or tertiary treatments) (OSPAR, 2009 p. 7) as the discharge of inadequately treated effluents can affect the levels of microbial pathogens in receiving waters (Shannon RBD, 2010 p. 11). Combined sewer overflows receive rainfall water, untreated wastewater and runoff during high precipitation events – all sources of faecal contamination – and can seriously impact bathing waters or shellfish areas (Lequette et al., 2006). Heavy rainfall will cause a rapid flushing through sewerage systems which can overload sewerage infrastructure (OSPAR, 2009 p. 8), and the resulting intermittent discharges have been identified as one of the major sources of shellfish contamination (Lee et al., 2003) Sewage network failures, in contrast to capacity overloading, are also a potential source of pollution. Sudden or prolonged storm events could contribute to this pollution and could trigger faecal contamination even during dry weather (OSPAR, 2009 p.7-8). Leaking from defective underground pipes or seepage from containment areas can lead to the microbiological contamination of bathing and shellfish waters (Shannon RBD, 2010 p. 11).On site wastewater treatment plants also pose a risk to surface water from microbial pathogens. Factors which may lead to these systems transferring contaminants to surface waters include: inadequate percolation in the catchment, whether suitable types of systems are selected, whether they are installed and maintained to appropriate standards, and whether they are situated close to bathing waters, designated shellfish areas, or to ditches, drains, watercourses, wells or boreholes. Monitoring indicates faecal contamination in some shellfish areas around Ireland’s coast could be arising from this source (e.g. DEHLG, 2009(a) p. 72). Approximately 64% of Ireland’s total land area is used for Agriculture (www.teagasc.ie) and the associated animal slurry, manure and silage is a common source of organic pollution and a likely source of faecal contamination in estuarine and coastal waters. The potential risk of harmful contamination from agricultural runoff will depend on factors such as soil type and slope of the land (e.g. DEHLG, 2009(b) p. 69). Discharges from marine based industry (e.g. shipping, leisure activities such as boating) may also cause high levels of microbial pathogens in the marine environment (OSPAR 2009 p.7). Inappropriately managed aquaculture activities can contribute to raised levels of microbial pathogens in marine waters by causing increasing the concentration of organic contamination around finfish cages (Shannon RBD, 2010 p.11). Proximity to ports, marinas and other coastal facilities is another possible source of microbiological contamination, with activities associated with boat movements in the vicinity of shellfish areas suggested as a potential source of faecal contamination in some of Ireland’s designated shellfish areas (DEHLG, 2009(c) p. 74). It is evident that land-based and marine-based activity can contribute to levels of microbial pathogens in the marine environment and thus pose potential health risks to humans. However, humans themselves also represent a source of faecal contamination in recreational waters. The WHO (1999) identified bather contamination as one of the most important sources of human faecal contamination in bathing waters. Other sources such as wild animals may also contribute to levels of microbial pathogens in the marine environment (OSPAR 2007 p.7).
The principal activities contributing to the pressure in the marine environment are discharges from municipal wastewater treatment works and run-off from agricultural lands. Wastewater from unsewered properties and sewage network failures have also been identified as contributing to levels of microbial pathogens in the marine environment. Sewage discharges including sewage outfall from wastewater treatment plants, combined sewer overflows and storm water discharges can contain high levels of microbial pathogens. These discharges will subsequently affect the levels of microbial pathogens in receiving waters. The type of treatment applied to wastewaters plays an important role in the microbiological load discharged into marine waters (physical, biological or tertiary treatments) (OSPAR, 2009 p. 7) as the discharge of inadequately treated effluents can affect the levels of microbial pathogens in receiving waters (Shannon RBD, 2010 p. 11). Combined sewer overflows receive rainfall water, untreated wastewater and runoff during high precipitation events – all sources of faecal contamination – and can seriously impact bathing waters or shellfish areas (Lequette et al., 2006). Heavy rainfall will cause a rapid flushing through sewerage systems which can overload sewerage infrastructure (OSPAR, 2009 p. 8), and the resulting intermittent discharges have been identified as one of the major sources of shellfish contamination (Lee et al., 2003) Sewage network failures, in contrast to capacity overloading, are also a potential source of pollution. Sudden or prolonged storm events could contribute to this pollution and could trigger faecal contamination even during dry weather (OSPAR, 2009 p.7-8). Leaking from defective underground pipes or seepage from containment areas can lead to the microbiological contamination of bathing and shellfish waters (Shannon RBD, 2010 p. 11).On site wastewater treatment plants also pose a risk to surface water from microbial pathogens. Factors which may lead to these systems transferring contaminants to surface waters include: inadequate percolation in the catchment, whether suitable types of systems are selected, whether they are installed and maintained to appropriate standards, and whether they are situated close to bathing waters, designated shellfish areas, or to ditches, drains, watercourses, wells or boreholes. Monitoring indicates faecal contamination in some shellfish areas around Ireland’s coast could be arising from this source (e.g. DEHLG, 2009(a) p. 72). Approximately 64% of Ireland’s total land area is used for Agriculture (www.teagasc.ie) and the associated animal slurry, manure and silage is a common source of organic pollution and a likely source of faecal contamination in estuarine and coastal waters. The potential risk of harmful contamination from agricultural runoff will depend on factors such as soil type and slope of the land (e.g. DEHLG, 2009(b) p. 69). Discharges from marine based industry (e.g. shipping, leisure activities such as boating) may also cause high levels of microbial pathogens in the marine environment (OSPAR 2009 p.7). Inappropriately managed aquaculture activities can contribute to raised levels of microbial pathogens in marine waters by causing increasing the concentration of organic contamination around finfish cages (Shannon RBD, 2010 p.11). Proximity to ports, marinas and other coastal facilities is another possible source of microbiological contamination, with activities associated with boat movements in the vicinity of shellfish areas suggested as a potential source of faecal contamination in some of Ireland’s designated shellfish areas (DEHLG, 2009(c) p. 74). It is evident that land-based and marine-based activity can contribute to levels of microbial pathogens in the marine environment and thus pose potential health risks to humans. However, humans themselves also represent a source of faecal contamination in recreational waters. The WHO (1999) identified bather contamination as one of the most important sources of human faecal contamination in bathing waters. Other sources such as wild animals may also contribute to levels of microbial pathogens in the marine environment (OSPAR 2007 p.7).
The principal activities contributing to the pressure in the marine environment are discharges from municipal wastewater treatment works and run-off from agricultural lands. Wastewater from unsewered properties and sewage network failures have also been identified as contributing to levels of microbial pathogens in the marine environment. Sewage discharges including sewage outfall from wastewater treatment plants, combined sewer overflows and storm water discharges can contain high levels of microbial pathogens. These discharges will subsequently affect the levels of microbial pathogens in receiving waters. The type of treatment applied to wastewaters plays an important role in the microbiological load discharged into marine waters (physical, biological or tertiary treatments) (OSPAR, 2009 p. 7) as the discharge of inadequately treated effluents can affect the levels of microbial pathogens in receiving waters (Shannon RBD, 2010 p. 11). Combined sewer overflows receive rainfall water, untreated wastewater and runoff during high precipitation events – all sources of faecal contamination – and can seriously impact bathing waters or shellfish areas (Lequette et al., 2006). Heavy rainfall will cause a rapid flushing through sewerage systems which can overload sewerage infrastructure (OSPAR, 2009 p. 8), and the resulting intermittent discharges have been identified as one of the major sources of shellfish contamination (Lee et al., 2003) Sewage network failures, in contrast to capacity overloading, are also a potential source of pollution. Sudden or prolonged storm events could contribute to this pollution and could trigger faecal contamination even during dry weather (OSPAR, 2009 p.7-8). Leaking from defective underground pipes or seepage from containment areas can lead to the microbiological contamination of bathing and shellfish waters (Shannon RBD, 2010 p. 11).On site wastewater treatment plants also pose a risk to surface water from microbial pathogens. Factors which may lead to these systems transferring contaminants to surface waters include: inadequate percolation in the catchment, whether suitable types of systems are selected, whether they are installed and maintained to appropriate standards, and whether they are situated close to bathing waters, designated shellfish areas, or to ditches, drains, watercourses, wells or boreholes. Monitoring indicates faecal contamination in some shellfish areas around Ireland’s coast could be arising from this source (e.g. DEHLG, 2009(a) p. 72). Approximately 64% of Ireland’s total land area is used for Agriculture (www.teagasc.ie) and the associated animal slurry, manure and silage is a common source of organic pollution and a likely source of faecal contamination in estuarine and coastal waters. The potential risk of harmful contamination from agricultural runoff will depend on factors such as soil type and slope of the land (e.g. DEHLG, 2009(b) p. 69). Discharges from marine based industry (e.g. shipping, leisure activities such as boating) may also cause high levels of microbial pathogens in the marine environment (OSPAR 2009 p.7). Inappropriately managed aquaculture activities can contribute to raised levels of microbial pathogens in marine waters by causing increasing the concentration of organic contamination around finfish cages (Shannon RBD, 2010 p.11). Proximity to ports, marinas and other coastal facilities is another possible source of microbiological contamination, with activities associated with boat movements in the vicinity of shellfish areas suggested as a potential source of faecal contamination in some of Ireland’s designated shellfish areas (DEHLG, 2009(c) p. 74). It is evident that land-based and marine-based activity can contribute to levels of microbial pathogens in the marine environment and thus pose potential health risks to humans. However, humans themselves also represent a source of faecal contamination in recreational waters. The WHO (1999) identified bather contamination as one of the most important sources of human faecal contamination in bathing waters. Other sources such as wild animals may also contribute to levels of microbial pathogens in the marine environment (OSPAR 2007 p.7).
The principal activities contributing to the pressure in the marine environment are discharges from municipal wastewater treatment works and run-off from agricultural lands. Wastewater from unsewered properties and sewage network failures have also been identified as contributing to levels of microbial pathogens in the marine environment. Sewage discharges including sewage outfall from wastewater treatment plants, combined sewer overflows and storm water discharges can contain high levels of microbial pathogens. These discharges will subsequently affect the levels of microbial pathogens in receiving waters. The type of treatment applied to wastewaters plays an important role in the microbiological load discharged into marine waters (physical, biological or tertiary treatments) (OSPAR, 2009 p. 7) as the discharge of inadequately treated effluents can affect the levels of microbial pathogens in receiving waters (Shannon RBD, 2010 p. 11). Combined sewer overflows receive rainfall water, untreated wastewater and runoff during high precipitation events – all sources of faecal contamination – and can seriously impact bathing waters or shellfish areas (Lequette et al., 2006). Heavy rainfall will cause a rapid flushing through sewerage systems which can overload sewerage infrastructure (OSPAR, 2009 p. 8), and the resulting intermittent discharges have been identified as one of the major sources of shellfish contamination (Lee et al., 2003) Sewage network failures, in contrast to capacity overloading, are also a potential source of pollution. Sudden or prolonged storm events could contribute to this pollution and could trigger faecal contamination even during dry weather (OSPAR, 2009 p.7-8). Leaking from defective underground pipes or seepage from containment areas can lead to the microbiological contamination of bathing and shellfish waters (Shannon RBD, 2010 p. 11).On site wastewater treatment plants also pose a risk to surface water from microbial pathogens. Factors which may lead to these systems transferring contaminants to surface waters include: inadequate percolation in the catchment, whether suitable types of systems are selected, whether they are installed and maintained to appropriate standards, and whether they are situated close to bathing waters, designated shellfish areas, or to ditches, drains, watercourses, wells or boreholes. Monitoring indicates faecal contamination in some shellfish areas around Ireland’s coast could be arising from this source (e.g. DEHLG, 2009(a) p. 72). Approximately 64% of Ireland’s total land area is used for Agriculture (www.teagasc.ie) and the associated animal slurry, manure and silage is a common source of organic pollution and a likely source of faecal contamination in estuarine and coastal waters. The potential risk of harmful contamination from agricultural runoff will depend on factors such as soil type and slope of the land (e.g. DEHLG, 2009(b) p. 69). Discharges from marine based industry (e.g. shipping, leisure activities such as boating) may also cause high levels of microbial pathogens in the marine environment (OSPAR 2009 p.7). Inappropriately managed aquaculture activities can contribute to raised levels of microbial pathogens in marine waters by causing increasing the concentration of organic contamination around finfish cages (Shannon RBD, 2010 p.11). Proximity to ports, marinas and other coastal facilities is another possible source of microbiological contamination, with activities associated with boat movements in the vicinity of shellfish areas suggested as a potential source of faecal contamination in some of Ireland’s designated shellfish areas (DEHLG, 2009(c) p. 74). It is evident that land-based and marine-based activity can contribute to levels of microbial pathogens in the marine environment and thus pose potential health risks to humans. However, humans themselves also represent a source of faecal contamination in recreational waters. The WHO (1999) identified bather contamination as one of the most important sources of human faecal contamination in bathing waters. Other sources such as wild animals may also contribute to levels of microbial pathogens in the marine environment (OSPAR 2007 p.7).
The principal activities contributing to the pressure in the marine environment are discharges from municipal wastewater treatment works and run-off from agricultural lands. Wastewater from unsewered properties and sewage network failures have also been identified as contributing to levels of microbial pathogens in the marine environment. Sewage discharges including sewage outfall from wastewater treatment plants, combined sewer overflows and storm water discharges can contain high levels of microbial pathogens. These discharges will subsequently affect the levels of microbial pathogens in receiving waters. The type of treatment applied to wastewaters plays an important role in the microbiological load discharged into marine waters (physical, biological or tertiary treatments) (OSPAR, 2009 p. 7) as the discharge of inadequately treated effluents can affect the levels of microbial pathogens in receiving waters (Shannon RBD, 2010 p. 11). Combined sewer overflows receive rainfall water, untreated wastewater and runoff during high precipitation events – all sources of faecal contamination – and can seriously impact bathing waters or shellfish areas (Lequette et al., 2006). Heavy rainfall will cause a rapid flushing through sewerage systems which can overload sewerage infrastructure (OSPAR, 2009 p. 8), and the resulting intermittent discharges have been identified as one of the major sources of shellfish contamination (Lee et al., 2003) Sewage network failures, in contrast to capacity overloading, are also a potential source of pollution. Sudden or prolonged storm events could contribute to this pollution and could trigger faecal contamination even during dry weather (OSPAR, 2009 p.7-8). Leaking from defective underground pipes or seepage from containment areas can lead to the microbiological contamination of bathing and shellfish waters (Shannon RBD, 2010 p. 11).On site wastewater treatment plants also pose a risk to surface water from microbial pathogens. Factors which may lead to these systems transferring contaminants to surface waters include: inadequate percolation in the catchment, whether suitable types of systems are selected, whether they are installed and maintained to appropriate standards, and whether they are situated close to bathing waters, designated shellfish areas, or to ditches, drains, watercourses, wells or boreholes. Monitoring indicates faecal contamination in some shellfish areas around Ireland’s coast could be arising from this source (e.g. DEHLG, 2009(a) p. 72). Approximately 64% of Ireland’s total land area is used for Agriculture (www.teagasc.ie) and the associated animal slurry, manure and silage is a common source of organic pollution and a likely source of faecal contamination in estuarine and coastal waters. The potential risk of harmful contamination from agricultural runoff will depend on factors such as soil type and slope of the land (e.g. DEHLG, 2009(b) p. 69). Discharges from marine based industry (e.g. shipping, leisure activities such as boating) may also cause high levels of microbial pathogens in the marine environment (OSPAR 2009 p.7). Inappropriately managed aquaculture activities can contribute to raised levels of microbial pathogens in marine waters by causing increasing the concentration of organic contamination around finfish cages (Shannon RBD, 2010 p.11). Proximity to ports, marinas and other coastal facilities is another possible source of microbiological contamination, with activities associated with boat movements in the vicinity of shellfish areas suggested as a potential source of faecal contamination in some of Ireland’s designated shellfish areas (DEHLG, 2009(c) p. 74). It is evident that land-based and marine-based activity can contribute to levels of microbial pathogens in the marine environment and thus pose potential health risks to humans. However, humans themselves also represent a source of faecal contamination in recreational waters. The WHO (1999) identified bather contamination as one of the most important sources of human faecal contamination in bathing waters. Other sources such as wild animals may also contribute to levels of microbial pathogens in the marine environment (OSPAR 2007 p.7).
Activity type
  • AgricultForestry
  • TourismRecreation
  • Urban
  • AgricultForestry
  • TourismRecreation
  • Urban
  • AgricultForestry
  • TourismRecreation
  • Urban
  • AgricultForestry
  • TourismRecreation
  • Urban
  • AgricultForestry
  • TourismRecreation
  • Urban
  • AgricultForestry
  • TourismRecreation
  • Urban
Information gaps
Current arrangements for assessing pressures under the SWD are limited because of the low sampling frequency preventing robust and reliable temporal trend analysis (pers. comm. Marine Institute). Classification of shellfish harvesting areas for hygiene purposes is conducted on an annual basis using the previous three years data for the area. A similar approach may also be employed for using data collected under the Shellfish Waters Directive. Further statistical approaches taking account of the level of Escherichia coli present in samples and not simply the percentage compliance with the guide value could also be developed to determine if bacteriological water quality has improved over a given period (Marine Institute, 2010 p. 10).
Current arrangements for assessing pressures under the SWD are limited because of the low sampling frequency preventing robust and reliable temporal trend analysis (pers. comm. Marine Institute). Classification of shellfish harvesting areas for hygiene purposes is conducted on an annual basis using the previous three years data for the area. A similar approach may also be employed for using data collected under the Shellfish Waters Directive. Further statistical approaches taking account of the level of Escherichia coli present in samples and not simply the percentage compliance with the guide value could also be developed to determine if bacteriological water quality has improved over a given period (Marine Institute, 2010 p. 10).
Current arrangements for assessing pressures under the SWD are limited because of the low sampling frequency preventing robust and reliable temporal trend analysis (pers. comm. Marine Institute). Classification of shellfish harvesting areas for hygiene purposes is conducted on an annual basis using the previous three years data for the area. A similar approach may also be employed for using data collected under the Shellfish Waters Directive. Further statistical approaches taking account of the level of Escherichia coli present in samples and not simply the percentage compliance with the guide value could also be developed to determine if bacteriological water quality has improved over a given period (Marine Institute, 2010 p. 10).
Current arrangements for assessing pressures under the SWD are limited because of the low sampling frequency preventing robust and reliable temporal trend analysis (pers. comm. Marine Institute). Classification of shellfish harvesting areas for hygiene purposes is conducted on an annual basis using the previous three years data for the area. A similar approach may also be employed for using data collected under the Shellfish Waters Directive. Further statistical approaches taking account of the level of Escherichia coli present in samples and not simply the percentage compliance with the guide value could also be developed to determine if bacteriological water quality has improved over a given period (Marine Institute, 2010 p. 10).
Current arrangements for assessing pressures under the SWD are limited because of the low sampling frequency preventing robust and reliable temporal trend analysis (pers. comm. Marine Institute). Classification of shellfish harvesting areas for hygiene purposes is conducted on an annual basis using the previous three years data for the area. A similar approach may also be employed for using data collected under the Shellfish Waters Directive. Further statistical approaches taking account of the level of Escherichia coli present in samples and not simply the percentage compliance with the guide value could also be developed to determine if bacteriological water quality has improved over a given period (Marine Institute, 2010 p. 10).
Current arrangements for assessing pressures under the SWD are limited because of the low sampling frequency preventing robust and reliable temporal trend analysis (pers. comm. Marine Institute). Classification of shellfish harvesting areas for hygiene purposes is conducted on an annual basis using the previous three years data for the area. A similar approach may also be employed for using data collected under the Shellfish Waters Directive. Further statistical approaches taking account of the level of Escherichia coli present in samples and not simply the percentage compliance with the guide value could also be developed to determine if bacteriological water quality has improved over a given period (Marine Institute, 2010 p. 10).