Faecal Coliforms in Bivalve Harvesting Areas of the Alvor Lagoon (Southern Portugal): Influence of Seasonal Variability and Urban Development

Campos, Carlos; Cachola, R.

doi:10.1007/s10661-006-9557-2

Cited by 30 publications

(13 citation statements)

References 21 publications

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“…In our study, the E. coli concentration in oysters correlated poorly with those in water (Fig. ), which is consistent with other field surveys performed on oysters (Bernard ; Ogburn and White ) or clams (Campos and Cachola ). On the contrary, some studies of bacterial accumulation by M. galloprovincialis and M. edulis showed good correlations between faecal coliform concentrations in shellfish and in water (Plusquellec et al .…”

Section: Discussionsupporting

confidence: 92%

“…Whereas our data set did not allow an effect of temperature on AF to be clearly detected, Burkhardt et al . () and Campos and Cachola () showed that bacterial accumulation by clams increased with temperature. Other authors have reported that the optimal temperature range for the maximal clearance and microbial accumulation rates of C. gigas (Bernard ; Bougrier et al .…”

Section: Discussionmentioning

confidence: 96%

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Impact of weather conditions on Escherichia coli accumulation in oysters of the Thau lagoon (the Mediterranean, France)

et al. 2012

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Aims: The Thau lagoon shellfish are regularly impacted by microbial pollution of faecal origin, which cause European health standards to be exceeded and closure of the shellfish harvest. The aims of this study were to investigate the impact of weather and hydrological conditions on Escherichia coli (E. coli) accumulation factor (AF) between water and oysters and to evaluate the relevance of the use of this ratio for the purpose of sanitary risk assessment. Methods and results: Water and oysters (Crassostrea gigas) were sampled simultaneously in situ during 18 months in periods of dry weather and after rainfall events. Shellfish sanitary thresholds were exceeded in both periods. The E. coli AFs measured after rainfall (median = 6) were lower than in dry weather (median = 32), suggesting different shellfish faecal contaminations were operating in this system process. Conclusion: The AFs we measured appeared to be relevant markers for generating sanitary risk assessments for Thau lagoon shellfish. Significance and impact of the study: The results of the study address the need to assess the relationship between water quality measures and shellfish flesh quality. This study will contribute to the elaboration of a management tool to guide local authorities in prioritizing the sources of pollution and in optimizing public investment in the watershed. IntroductionWith up to 13 000 tons of oysters (Crassostrea gigas) and 2500 tons of mussels (Mytilus galloprovincialis) marketed every year, the Thau lagoon is the main shellfish harvesting area in the Mediterranean. Filter-feeding bivalves, such as oysters, filter large volumes of water from their environment and are able to concentrate large numbers of particles, which include micro-organisms pathogenic to human consumers (Bernard 1989;Plusquellec et al. 1990). According to European sanitary rules, the Escherichia coli concentrations found in Thau shellfish correspond to a Class B area. As a result, shellfish must be depurated before they can be marketed. Because Thau lagoon shellfish regularly exceed current health standards, authorities periodically restrict the shellfish harvesting area and, in some cases, suspend production. Moreover, several enteric virus outbreaks due to Thau lagoon oysters occurred during winter gastroenteritis epidemics in the local population .Many studies have shown the impact of rainfall on microbial water quality in coastal and estuarine areas. Contamination due to rainfall most often results from urban wastewater discharges or from nonpoint pollution sources in the watershed (Lipp et al. 2001;Chigbu et al. 2005;Jeng et al. 2005;Coulliette and Noble 2008;Papastergiou et al. 2009;Chu et al. 2011;Conn et al. 2012). Microbial contamination can also occur in dry weather conditions, in which faecal material from seabirds resting on shellfish farming structures is the likely main source (Levesque et al. 2000;Wither et al. 2005;Ogburn and White 2009;Derolez et al. 2010).European regulations recommend monitoring coliform bacteria (e.g. E. coli...

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Section: Discussionsupporting

confidence: 92%

Section: Discussionmentioning

confidence: 96%

Impact of weather conditions on Escherichia coli accumulation in oysters of the Thau lagoon (the Mediterranean, France)

et al. 2012

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“…Studies on urban-affected watersheds have found those watersheds to contain one to two magnitude higher concentrations of FIBs (30) and that greater urbanization increased the probability of EPA water quality criteria being exceeded (25). Urbanization of watersheds may also negatively affect water quality in downstream areas, such as lagoons (9) and estuaries (19). Many previous land use studies, however, were prompted by pre-existing contamination issues and were often in areas affected by urban activities, such as wastewater effluent (13,18) and storm runoff (28,39), or by agricultural operations, such as pasture land (12,23) and manure application (1,25).…”

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confidence: 99%

Effects of Land Uses on Fecal Indicator Bacteria in the Water and Soil of a Tropical Watershed

Goto

Yan

2011

Microb. Environ.

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Effects of different land uses on densities of Escherichia coli, enterococci, and Clostridium perfringens in the water and soil of a tropical watershed were investigated. Densities of fecal indicator bacteria (FIBs) in the watershed exhibited a clear land-use dependency in the stream water. Significantly higher concentrations were detected in the urban portion of the stream (417, 420, and 44 CFU 100 mL −1 for E. coli, enterococci, and C. perfringens, respectively) than in the forest portion (54, 32, and 5 CFU 100 mL −1 for E. coli, enterococci, and C. perfringens, respectively). High concentrations of FIBs were also detected in the soil of the watershed with concentration ranges of 603-1,820,000, 69-17,000, and 0-525 CFU 100 g soil −1 for E. coli, enterococci, and C. perfringens, respectively, which however were not affected by the different land uses. Prior cumulative rainfall significantly correlated with concentrations of E. coli and enterococci in the urban stream water (r=0.73-0.87, P<0.05), but not with the alternative FIB C. perfringens. Poor correlations were observed in the forest reach of the stream for all FIBs. Furthermore, the concentration of C. perfringens only correlated strongly and significantly with E. coli and enterococci in stream water (r=0.70-0.82, P<0.05), but not in tropical soil, indicating different survival and transport behaviors.

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“…FCB and TCB are commonly used indicators of sanitary quality of the water, especially wastes from human and warm-blooded animals [25]. Apart from cluster A, FCB and TCB in cluster B were very far beyond the criteria for "fairly clean used" water quality standard in Thailand i.e.…”

Section: Discussionmentioning

confidence: 96%

Spatio-Temporal Variations in Water Quality of the Chao Phraya River, Thailand, between 1991 and 2008

Avakul¹,

Jutagate²

2012

JWARP

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Spatio-temporal variations in the water quality of the Chao Phraya River, Thailand, were examined, on average-yearly basis, between 1999 and 2008, from 32 surface water stations from the river origin to the delta. Five water quality parameters viz., DO, BOD, TCB, FCB, NH3-N and water temperature were used in the analysis. Analysis was performed by using the Self Organizing Maps. Four distinct spatially approached clusters were classified, according to the similarity of water quality parameters, while temporal variations of most of the surface water stations were not obviously observed. The worst water quality condition was at the stations near the river delta and highly related to anthropogenic stresses. Result from the correspondence analysis showed that, except for the cluster of the worst water quality, the stations of the remaining three clusters were overlapped. There was no statistical difference in water temperature among clusters but the expected effects from climate change should be a precautionary focus since the will eventually affect the water quality.

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Faecal Coliforms in Bivalve Harvesting Areas of the Alvor Lagoon (Southern Portugal): Influence of Seasonal Variability and Urban Development

Cited by 30 publications

References 21 publications

Impact of weather conditions on Escherichia coli accumulation in oysters of the Thau lagoon (the Mediterranean, France)

Impact of weather conditions on Escherichia coli accumulation in oysters of the Thau lagoon (the Mediterranean, France)

Effects of Land Uses on Fecal Indicator Bacteria in the Water and Soil of a Tropical Watershed

Spatio-Temporal Variations in Water Quality of the Chao Phraya River, Thailand, between 1991 and 2008

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