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1.
J Neurol Surg B Skull Base ; 82(6): 638-642, 2021 Dec.
Article in English | MEDLINE | ID: mdl-34745831

ABSTRACT

Objective The aim of this study is to present our experience in dealing with middle ear adenomas (MEAs), very rare tumors of the middle ear. Methods The medical notes of individuals with MEAs treated in tertiary referral; academic settings were retrospectively reviewed. We recorded the presenting symptoms, imaging findings, and pathology results. We additionally examined our surgical outcomes, follow-up period, recurrence, and morbidity. Results We identified four patients with MEAs: two males and two females with an average age of 36.25 years (range = 27-51 years). Despite the detailed imaging studies, including computed tomography and magnetic resonance imaging with intravenous contrast administration, a biopsy was essential in setting the diagnosis. Total surgical resection was achieved in all patients without any recurrence over an average of 6 years (range = 3-10 years). Complete ipsilateral deafness was the commonest surgical morbidity due to footplate infiltration by the tumor. Conclusion Total surgical resection is the treatment of choice in MEAs to minimize the risk for recurrence; this can come with morbidity, mostly sensorineural deafness. Given the very limited literature, long-term follow-up is recommended.

2.
Otol Neurotol ; 42(2): e216-e221, 2021 02 01.
Article in English | MEDLINE | ID: mdl-33252368

ABSTRACT

OBJECTIVE: To identify the optimal time for imaging following stereotactic radiosurgery (SRS) in patients with vestibular schwannomas (VS). STUDY DESIGN: Retrospective case series. SETTING: Tertiary, university center. PATIENTS: Patients with VS treated with SRS. INTERVENTIONS: Pre- and post-SRS surveillance with magnetic resonance imaging (MRI); patients should have at least two pre- and two post-SRS scans available to be included. MAIN OUTCOME MEASURES: Patient demographics, tumor size, and growth per month ratio pre- and post-SRS and time interval between serial MRI. RESULTS: Forty-two patients fulfilled the inclusion criteria. The average tumor size before the treatment was 16.9 mm (range, 10-28 mm) while 2 years posttreatment it was 16 mm (range, 7-25 mm) (p = 0.5). Average time of the first MRI post-SRS was 11 months (range, 5-14) with an average change in tumor size at that time of +0.53 mm (range, -5-8). Average time to second MRI was 22.3 months (range, 12-33) with an average change in tumor size at second scan of -1.14 (range, -5-2) mm (p = 0.117). The average growth/mo ratio before SRS was 0.26 mm/mo (range, 0-1), while post-SRS 0.05 mm/mo (range, -0.3-0.5) and -0.16 mm/mo (range, -18-0.25) at the time of the first and second scan, respectively (p < 0.001). CONCLUSIONS: Given the initial increase in size following SRS, unless clinically indicated, MRI post-SRS at less than 1 year has no clinical value. The growth per month ratio provides more meaningful values for response to treatment than tumor size measurements.


Subject(s)
Neuroma, Acoustic , Radiosurgery , Follow-Up Studies , Humans , Magnetic Resonance Imaging , Neuroma, Acoustic/diagnostic imaging , Neuroma, Acoustic/radiotherapy , Neuroma, Acoustic/surgery , Retrospective Studies , Treatment Outcome
3.
Skeletal Radiol ; 49(7): 1081-1088, 2020 Jul.
Article in English | MEDLINE | ID: mdl-32006113

ABSTRACT

OBJECTIVE: Distal biceps brachii tendon (DBBT) rupture is an uncommon but functionally significant injury given the loss of supination, flexion strength and pain that often result. Prompt surgical repair is preferred in most patients. Clinicoradiological post-operative follow-up is typically performed to assess DBBT repair integrity and function, frequently using ultrasound, though to date, no studies have described post-operative DBBT repair sonographic appearances. The purpose of this study was to evaluate post-operative DBBT sonographic appearances in the context of Endobutton repair with the following aims:i.Establish typical ultrasound appearances 12 months post-surgeryii.Establish the relationship between ultrasound appearances and clinical/functional outcomes. MATERIALS AND METHODS: Sixty patients between February 2016 and October 2017 undergoing DBBT repair were prospectively recruited, all undergoing clinical and sonographic assessment 12 months post-surgery. Ultrasound data was collected on tendon integrity, tendon calibre and presence of intratendinous calcification, peritendinous fluid and peritendinous soft tissue/scarring. Clinical data was collected on active range of motion (ROM) (flexion, extension, supination, pronation) and strength (flexion and supination). RESULTS: A total of 57/60 patients had intact DBBT repairs identified sonographically and clinically at 12 months. DBBT repairs had significantly increased cross-sectional area (mean 260%, 95% CI: 217%, 303%) compared with non-operated DBBT. Ninety-three percent of DBBT repairs were hypoechoic. Thirty percent contained intratendinous calcification. Peritendinous fluid/soft tissue was rarely observed. There was no significant correlation between DBBT calibre and strength/ROM parameters. CONCLUSION: Normal post-operative sonographic appearances of Endobutton DBBT repair comprise a hypoechoic tendon significantly increased in calibre compared with non-operated tendon ± intratendinous calcification. DBBT repair calibre varies greatly, but is not associated with any significant difference in strength/ROM.


Subject(s)
Arm Injuries/diagnostic imaging , Arm Injuries/surgery , Elbow Joint/diagnostic imaging , Elbow Joint/surgery , Tendon Injuries/diagnostic imaging , Tendon Injuries/surgery , Ultrasonography/methods , Adult , Aged , Humans , Male , Middle Aged , Prospective Studies , Range of Motion, Articular , Rupture/diagnostic imaging , Rupture/surgery
5.
Clin Exp Otorhinolaryngol ; 12(4): 392-398, 2019 Nov.
Article in English | MEDLINE | ID: mdl-31109159

ABSTRACT

OBJECTIVES: To investigate the impact of labyrinthectomy and intratympanic (IT) gentamicin injections on the contralateral labyrinth, we also assessed the response of each individual semicircular canal to each IT gentamicin application. METHODS: We performed a pilot observational study on tertiary, referral, academic settings. Thirteen patients with unilateral vestibular pathology were organized into two groups, group I (seven patients) receiving IT gentamicin and group II undergoing labyrinthectomy (six patients). All patients underwent six-canal video-head-impulse test in predetermined time intervals. Patients receiving gentamicin were additionally tested 3 to 5 days after every sequential injection, until all ipsilateral canals were ablated, to determine the order of response to gentamicin. We recorded the vestibular-ocular reflex gains and the presence of covert/overt saccades for each canal. RESULTS: The posttreatment ipsilateral gains were abnormal. No patient from the gentamicin group developed abnormal contralateral responses, while patients undergoing labyrinthectomy had abnormal contralateral responses from at least one canal, even several months posttreatment. Finally, the lateral semicircular canal was the first one to be affected by IT gentamicin followed by the posterior canal: the superior canal was ablated last. CONCLUSION: In our study, labyrinthectomy had an impact on the responses recorded from the contralateral ear, while IT gentamicin ablated the ipsilateral labyrinthine function without affecting the contralateral responses, possibly because of a milder, more gradual impact. We also show for the first time the order that IT gentamicin application affects the semicircular canals, with the lateral being the first to be affected.

7.
Otol Neurotol ; 39(10): e1118-e1124, 2018 12.
Article in English | MEDLINE | ID: mdl-30106843

ABSTRACT

OBJECTIVE: To explore the nature of spontaneously regressing vestibular schwannomas (VS) and identify possible predictive factors for such behavior. STUDY DESIGN: Retrospective case control study. SETTING: Tertiary referral center, university teaching hospital. PATIENTS: Patients with sporadic VS demonstrating spontaneous regression compared with a control group of patients with growing VS. INTERVENTIONS: Review of serial magnetic resonance imaging of the internal auditory meatus (MRI IAM) and case notes and direct comparison of possible related factors between the two groups using univariate analysis. MAIN OUTCOME MEASURES: Presenting symptoms, VS size and consistency, patients' age and sex, tumor laterality and location, and the neutrophil-to-lymphocyte ratio between the two groups. RESULTS: Of the 540 patients on the database 28 (5.2%) showed spontaneous regression with a mean follow-up of 122 months. Mean absolute and relative regression was 3.9 mm and 25.7%, respectively. 60% of tumors showed gradual regression while 25% showed growth followed by regression. Regressing VS had a significantly larger size than the control group; while the regressing tumors were located further from the fundus than the control group. The remaining examined factors did not reach a statistical level of significance. CONCLUSION: This is, to our knowledge, the first study comparing a cohort of regressing tumors with a control group of growing VS. The finding that the location of tumors around the porous, is more common in regressing VS has implications for patients' counselling.


Subject(s)
Neoplasm Regression, Spontaneous , Neuroma, Acoustic/pathology , Adult , Aged , Case-Control Studies , Female , Humans , Magnetic Resonance Imaging , Male , Middle Aged , Retrospective Studies
8.
Water Res ; 143: 229-239, 2018 10 15.
Article in English | MEDLINE | ID: mdl-29960177

ABSTRACT

Faecal indicator organisms (FIOs) are major pollutants in many catchments world-wide, with streamside pastures on livestock farms being potentially significant sources. Hitherto, few empirical studies have quantified FIO fluxes from such areas or investigated streambank fencing (SBF) and other possible mitigation measures. The aim of this two-phase (before/after intervention) study of the effectiveness of SBF was to generate an empirical evidence-base to enable regulatory authorities to make better-informed decisions concerning the implementation of this measure. It was undertaken during the summer bathing season along a 271 m stream reach in the River Tamar catchment, SW England. The study included: cattle distribution surveys; monitoring of changes in E. coli (EC) and intestinal enterococci (IE) concentrations and fluxes down the reach and of concentrations in ditch flow and surface runoff; phage tracer studies of surface runoff from pasture land; and experimental streambed trampling to investigate streambed FIO sources. The results show that cattle spend a disproportionately large amount of time in the watercourse/riparian zone along unfenced streams; identify direct defecation to the stream by wading livestock and the release/mobilisation of FIOs from cowpats by surface runoff from the adjacent pastures at times of high flow as key transmission routes; and demonstrate that FIOs become incorporated within streambed sediments, from which they may subsequently be released by trampling. Partial exclusion of cattle through SBF with a drinking bay greatly reduces the time cattle spend in streams. Total exclusion SBF, with provision of an alternative drinking supply, considerably reduces FIO load inputs to the stream reach, e.g. at times of high flow, which are critical in terms of pollutant fluxes to coastal waters, the mean EC and IE input loads to the reach fell by 0.842 and 2.206 log10, respectively.


Subject(s)
Agriculture/methods , Feces/microbiology , Rivers/microbiology , Water Pollution/prevention & control , Animals , Cattle , England , Enterococcus , Environmental Biomarkers , Environmental Monitoring/methods , Escherichia coli , Farms
9.
Otol Neurotol ; 39(2): e143-e150, 2018 02.
Article in English | MEDLINE | ID: mdl-29315190

ABSTRACT

OBJECTIVE: Recent studies have suggested good hearing preservation following stereotactic radiosurgery (STRS) in patients with vestibular schwannomas (VS). This study aims to assess audiological outcomes in patients with growing VS treated either with STRS, or managed conservatively. STUDY DESIGN: Retrospective cohort study. SETTING: Tertiary referral center. PATIENTS: Out of 540 patients with VS, 69 patients with growing VS fulfilled the inclusion criteria; 24 treated conservatively and 45 with STRS. VS were considered growing if demonstrating more than 15% tumor volume increase during 1 year of watchful waiting. INTERVENTION: American Association of Otolaryngology-Head and Neck Surgery (AAOHNS) hearing threshold (dB averaged over 500-3000 Hz) deterioration and Gardner-Robertson class deterioration over time were used as the primary outcome measures. Rate of progression to loss of functional hearing (Gardner-Robertson class I-II) was also determined between cohorts. RESULTS: Mean follow-up was similar between treatment cohorts (STRS = 69.6 mo, conservative management = 71.7 mo). There was no significant difference in AAOHNS deterioration (t = 1.05, df = 53, p = 0.301) or Gardner-Robertson deterioration (χ = 0.47, df = 1, p = 0.492) between cohorts. Furthermore, rate of progression to loss of functional hearing was similar between cohorts (Hazard ratio = 0.704, 95% CI 0.287-1.728, p = 0.44). In STRS patients, AAOHNS deterioration was greater in those with lower AAOHNS thresholds at diagnosis (t = -2.683, df = 28, p = 0.0121). Similarly, Gardner-Robertson deterioration was significantly more likely in STRS patients with functional hearing (Gardner-Robertson class I-II) (Adjusted odds ratio = 32.14, 95% CI 3.15-328, p = 0.0034). CONCLUSIONS: STRS results in similar audiological outcomes compared with patients managed conservatively; Consequently, STRS given to patients with VS to preserve hearing is not justified. In contrast to recent studies, patients with preserved hearing at diagnosis have significantly greater audiological deterioration when undergoing STRS.


Subject(s)
Neuroma, Acoustic/therapy , Radiosurgery/methods , Watchful Waiting/methods , Adult , Aged , Disease Progression , Female , Humans , Male , Middle Aged , Retrospective Studies , Treatment Outcome
10.
PLoS One ; 12(5): e0175489, 2017.
Article in English | MEDLINE | ID: mdl-28493872

ABSTRACT

BACKGROUND: Although the natural history of vestibular schwannomas (VS) has been previously studied, few studies have investigated associated epidemiological factors, primarily because of the lack of large available cohorts. OBJECTIVE: The objective of this study was to perform a multi-scale geographical analysis of the period prevalence of VS in West Scotland from 2000 to 2015. METHODS: Adults diagnosed with sporadic VS were identified through the National Health Services of West Scotland database and geocoded to the unit postcode. To assess whether the cohort of VS cases could be pooled into a period prevalence measure, the locations of VS cases were analyzed by sex using Cross-L and Difference-K functions. VS period prevalence was examined at two aggregate spatial scales: the postcode district and a coarser scale of NHS Health Boards. The spatial structure of period prevalence within each level of spatial aggregation was measured using univariate global and local Moran's I. Bivariate local Moran's I was used to examine the between-scale variability in period prevalence from the postcode district level to the NHS Health Boards levels. Prior to spatial autocorrelation analyses, the period prevalence at the postcode district was tested for stratified spatial heterogeneity within the NHS Health Boards using Wang's q-Statistic. RESULTS: A total of 512 sporadic VS were identified in a population of over 3.1 million. Between 2000 and 2015, VS period prevalence was highest within the NHS Health Boards of Greater Glasgow and Clyde, Ayrshire and Arran and the Western Isles. However, at the NHS scale, period prevalence exhibited no spatial autocorrelation globally or locally. At the district scale, Highland exhibited the most unusual local spatial autocorrelation. Bivariate local Moran's I results indicated general stability of period prevalence across the postcode district to Health Boards scales. However, locally, some postcode districts in Greater Glasgow and Clyde, Ayrshire and Arran exhibited unusually low district to zone spatial autocorrelation in period prevalence, as did the southern parts of the Western Isles. Some unusually high period prevalence values between the postcode district to Health Board scale were found in Tayside, Forth Valley and Dumfries and Galloway. CONCLUSION: Geographic variability in VS in West Scotland was identified in this patient population, showing that there are areas, even remote, with unusually high or low period prevalence. This can be partially attributed to links between primary and tertiary care. Potential genetic or environmental risk factors that may contribute to geographic variation in this disease within Scotland are also a possibility but require further investigation.


Subject(s)
Environment , Geography , Neuroma, Acoustic/epidemiology , Adult , Aged , Aged, 80 and over , Databases, Factual , Female , Humans , Magnetic Resonance Imaging , Male , Middle Aged , Neurofibromatosis 2/diagnostic imaging , Neurofibromatosis 2/pathology , Neuroma, Acoustic/diagnostic imaging , Neuroma, Acoustic/pathology , Risk Factors , Scotland/epidemiology , Spatial Analysis
11.
Otol Neurotol ; 38(2): 260-263, 2017 02.
Article in English | MEDLINE | ID: mdl-28068303

ABSTRACT

OBJECTIVE: To enhance understanding of the behavior of vestibular schwannomas (VS) after stereotactic radiosurgery (SRS), including the potential for late tumor regrowth, and the need for lifelong radiological and clinical surveillance. PATIENTS: From a total of 540 patients with VS and out of 95 patients receiving SRS for their growing VS, the cases of two women patients aged 58 and 59 years with medium sized, growing VS are presented. INTERVENTION: Both patients were treated with SRS. Following treatment, both patients had close clinical follow-up and serial magnetic resonance imaging (MRI). MAIN OUTCOME MEASURES: Post-SRS clinical assessment and serial MRI to determine VS size and respond to treatment. RESULTS: Close clinical follow-up after SRS identified no change in symptoms in one patient; the other developed ipsilateral facial nerve twitching without weakness. Serial MRI identified that in both patients, VS that had initially decreased in size following SRS, exhibited significant late regrowth after a 3-year period, reaching the pretreatment size. CONCLUSIONS: This is the first report of late vestibular schwannoma regrowth following a period of significant shrinkage after SRS. Potential reason may be the presence of living cells within the tumor; the possibility of malignant transformation should also be taken into account. Following SRS, patients with VS warrant lifelong radiological and clinical surveillance, even following good response, as there seems to be a small chance of initial regression followed by further growth. Microsurgery for tumor removal and histological diagnosis is indicated in such cases.


Subject(s)
Neoplasm Recurrence, Local/pathology , Neuroma, Acoustic/pathology , Neuroma, Acoustic/radiotherapy , Radiosurgery , Adult , Aged , Female , Follow-Up Studies , Humans , Magnetic Resonance Imaging , Male , Middle Aged , Treatment Outcome
13.
Otol Neurotol ; 37(5): 580-5, 2016 06.
Article in English | MEDLINE | ID: mdl-27093024

ABSTRACT

OBJECTIVE: To examine the predictive value of neutrophil to lymphocyte ratio (NLR) for vestibular schwannoma (VS) growth. STUDY DESIGN: Retrospective case-control study. SETTING: Tertiary, referral center. PATIENTS: Patients with sporadic VS and available NLR obtained within 1 year from the diagnosis were divided into two groups with growing or non-growing tumor. Patients with known conditions affecting NLR were excluded. INTERVENTIONS: NLR and tumor growth as determined by linear measurements on serial magnetic resonance imaging. MAIN OUTCOME MEASURES: VS growth, demographic factors, and NLR were compared using multi-variant logistic regression and Receiver Operating Characteristic (ROC) curve analysis. RESULTS: A total of 161 patients fulfilled the inclusion criteria, 79 with growing VS (men:women ratio = 43:36, mean age, 61.8 years) and 82 with non-growing tumors (men:women ratio = 37:45, mean age, 64.9 years). Mean NLR for the group with growing VS was 3.34 (SD [standard deviation] = 1.5) and 2.31 (SD = 0.76) for the group with non-growing VS (p = 0.001; 0.03 when adjusted for all parameters). The optimal cut-off point was NLR = 3.05 with positive predictive value 83.8% and 100% for NLR greater than 5.3. ROC analysis of the adjusted data for age, sex, and side, gave an area under the curve of 0.768, indicating NLR as a good independent predictive marker. Interestingly, the size of tumor was statistically significantly higher for the growing VS group (p = 0.001). CONCLUSION: Despite the low specificity of low NLR, our results indicate high NLR as a good predictive marker for VS growth. Confirmation by prospective studies will have a significant impact on patients' management.


Subject(s)
Lymphocytes , Neuroma, Acoustic/pathology , Neutrophils , Aged , Area Under Curve , Biomarkers/analysis , Case-Control Studies , Female , Humans , Lymphocyte Count , Male , Middle Aged , Predictive Value of Tests , Prospective Studies , ROC Curve , Retrospective Studies , Sensitivity and Specificity
14.
Br J Oral Maxillofac Surg ; 53(9): 814-9, 2015 Nov.
Article in English | MEDLINE | ID: mdl-26212419

ABSTRACT

We describe the technical aspects and report our clinical experience of a surgical approach to the infratemporal fossa that aims to reduce local recurrence after operations for cancer of the posterior maxilla. We tested the technique by operating on 3 cadavers and then used the approach in 16 patients who had posterolateral maxillectomy for disease that arose on the maxillary alveolus or junction of the hard and soft palate (maxillary group), and in 19 who had resection of the masticatory compartment and central skull base for advanced sinonasal cancer (sinonasal group). Early proximal ligation of the maxillary artery was achieved in all but one of the 35 patients. Access to the infratemporal fossa enabled division of the pterygoid muscles and pterygoid processes under direct vision in all cases. No patient in the maxillary group had local recurrence at median follow up of 36 months. Four patients (21%) in the sinonasal group had local recurrence at median follow up of 27 months. Secondary haemorrhage from the cavernous segment of the internal carotid artery resulted in the only perioperative death. The anterolateral corridor approach enables controlled resection of tumours that extend into the masticatory compartment.


Subject(s)
Skull Base/surgery , Head , Humans , Maxilla , Neoplasm Recurrence, Local , Skull Base Neoplasms
16.
Br J Oral Maxillofac Surg ; 51(5): 389-93, 2013 Jul.
Article in English | MEDLINE | ID: mdl-23089331

ABSTRACT

Local recurrence remains the most important sign of relapse of disease after treatment of advanced cancer of the maxilla and sinonasal region. In this retrospective study we describe patterns of recurrence in a group of patients who had had open resection for cancer of the sinonasal region and posterior maxillary alveolus with curative intent. Casenotes and imaging studies were reviewed to find out the pattern of any relapse, with particular reference to local recurrence. The minimum follow-up period was 12 months. Of 50 patients a total of 16 developed recurrences, 11 of which were local. Of those 11, a total of 8 were in posterior and superior locations (the orbit, the infratemporal and pterygopalatine fossas, the traversing neurovascular canals of the body of the sphenoid to the cavernous sinus, the Gasserian ganglion, and the dura of the middle cranial fossa). Advanced cancer of the midface often equates with disease at the skull base. Treatment, including surgical tactics, should reflect that.


Subject(s)
Alveolar Process/pathology , Maxillary Neoplasms/surgery , Neoplasm Recurrence, Local/pathology , Paranasal Sinus Neoplasms/surgery , Adolescent , Adult , Aged , Aged, 80 and over , Alveolectomy/methods , Carcinoma, Squamous Cell/pathology , Carcinoma, Squamous Cell/surgery , Cavernous Sinus/pathology , Cranial Nerve Neoplasms/pathology , Dura Mater/pathology , Female , Follow-Up Studies , Humans , Male , Middle Aged , Neoplasm Staging , Orbital Neoplasms/pathology , Retrospective Studies , Salvage Therapy , Skull Base Neoplasms/pathology , Skull Neoplasms/pathology , Sphenoid Bone/pathology , Survival Rate , Trigeminal Ganglion/pathology , Young Adult
17.
Water Res ; 44(16): 4748-59, 2010 Sep.
Article in English | MEDLINE | ID: mdl-20708770

ABSTRACT

The Water Framework Directive has caused a paradigm shift towards the integrated management of recreational water quality through the development of drainage basin-wide programmes of measures. This has increased the need for a cost-effective diagnostic tool capable of accurately predicting riverine faecal indicator organism (FIO) concentrations. This paper outlines the application of models developed to fulfil this need, which represent the first transferrable generic FIO models to be developed for the UK to incorporate direct measures of key FIO sources (namely human and livestock population data) as predictor variables. We apply a recently developed transfer methodology, which enables the quantification of geometric mean presumptive faecal coliforms and presumptive intestinal enterococci concentrations for base- and high-flow during the summer bathing season in unmonitored UK watercourses, to predict FIO concentrations in the Humber river basin district. Because the FIO models incorporate explanatory variables which allow the effects of policy measures which influence livestock stocking rates to be assessed, we carry out empirical analysis of the differential effects of seven land use management and policy instruments (fiscal constraint, production constraint, cost intervention, area intervention, demand-side constraint, input constraint, and micro-level land use management) all of which can be used to reduce riverine FIO concentrations. This research provides insights into FIO source apportionment, explores a selection of pollution remediation strategies and the spatial differentiation of land use policies which could be implemented to deliver river quality improvements. All of the policy tools we model reduce FIO concentrations in rivers but our research suggests that the installation of streamside fencing in intensive milk producing areas may be the single most effective land management strategy to reduce riverine microbial pollution.


Subject(s)
Environmental Monitoring , Feces/microbiology , Rivers/microbiology , Water Microbiology , Water Pollution/analysis , Water Supply/analysis , Animals , Enterococcus/isolation & purification , Environmental Restoration and Remediation/methods , Food/standards , Food Microbiology/standards , Humans , Intestines/microbiology , Predictive Value of Tests , Risk Assessment , Seasons , United Kingdom , Water Supply/standards
18.
J Environ Monit ; 9(5): 427-39, 2007 May.
Article in English | MEDLINE | ID: mdl-17492088

ABSTRACT

As the requirements of the Water Framework Directive (WFD) and the US Clean Water Act (USCWA) for the maintenance of microbiological water quality in 'protected areas' highlight, there is a growing recognition that integrated management of point and diffuse sources of microbial pollution is essential. New information on catchment microbial dynamics and, in particular, the sources of faecal indicator bacteria found in bathing and shellfish harvesting waters is a pre-requisite for the design of any 'programme of measures' at the drainage basin scale to secure and maintain compliance with existing and new health-based microbiological standards. This paper reports on a catchment-scale microbial source tracking (MST) study in the Leven Estuary drainage basin, northwest England, an area for which quantitative faecal indicator source apportionment empirical data and land use information were also collected. Since previous MST studies have been based on laboratory trials using 'manufactured' samples or analyses of spot environmental samples without the contextual microbial flux data (under high and low flow conditions) and source information, such background data are needed to evaluate the utility of MST in USCWA total maximum daily load (TMDL) assessments or WFD 'Programmes of Measures'. Thus, the operational utility of MST remains in some doubt. The results of this investigation, using genotyping of Bacteroidetes using polymerase chain reaction (PCR) and male-specific ribonucleic acid coliphage (F + RNA coliphage) using hybridisation, suggest some discrimination is possible between livestock- and human-derived faecal indicator concentrations but, in inter-grade areas, the degree to which the tracer picture reflected the land use pattern and probable faecal indicator loading were less distinct. Interestingly, the MST data was more reliable on high flow samples when much of the faecal indicator flux from catchment systems occurs. Whilst a useful supplementary tool, the MST information did not provide quantitative source apportionment for the study catchment. Thus, it could not replace detailed empirical measurement of microbial flux at key catchment outlets to underpin faecal indicator source apportionment. Therefore, the MST techniques reported herein currently may not meet the standards required to be a useful forensic tool, although continued development of the methods and further catchment scale studies could increase confidence in such methods for future application.


Subject(s)
Bathing Beaches , Environmental Monitoring , Forensic Medicine/methods , Water Microbiology , Water Supply/analysis , Animals , Coliphages/isolation & purification , England , Feces/microbiology , Geography , Humans , In Situ Hybridization, Fluorescence/methods , Nucleic Acids/analysis , Risk Assessment , Sewage/microbiology , Shellfish
19.
Water Res ; 39(16): 3967-81, 2005 Oct.
Article in English | MEDLINE | ID: mdl-16112711

ABSTRACT

The Ribble drainage basin is the single UK sentinel study area chosen for examining the implementation of the EU Water Framework Directive (WFD 20/60/EC). The study which has generated the data for this paper was initiated to quantify 'catchment-derived' fluxes of faecal indicators originating from both point and diffuse sources to inform the competent authorities on the potential for, and prioritization of, further options for reducing the faecal indicator loadings to this crucial coastal environment. It represents the first UK drainage basin-scale 'profile' of faecal indicator sources as recommended by WHO [1999. Health Based Monitoring of Recreational Waters: The Feasibility of a New Approach; the "Annapolis Protocol". World Health Organisation Geneva, Switzerland; 2003. Guidelines for Safe Recreational-Water Environments Volume 1: Coastal and Fresh-Waters. World Health Organisation Geneva, Switzerland] and incorporated into current drafts of the revised Bathing Water Directive [Anon, 2004. Council of the European Communities Amended proposal for a Directive of the European Parliament and of the Council concerning the management of bathing water quality. Brussels 23rd June]. This paper focuses on the relationships between land use and faecal indicator organism concentrations in surface waters within this very large drainage basin (1583 km2) containing some extensive urban areas. A geographical information system comprising readily available digital elevation, remotely sensed land cover and digital map data was used to generate the land use variables for subcatchments draining to 41 locations across the study area. Presumptive concentrations of coliforms, Escherichia coli and enterococci (colony forming unit (cfu) 100 ml(-1)) were measured at each location on at least 20 occasions over a 44-day period within the 2002 bathing season. The sampling programme targeted hydrograph events. Hydrometric records were used to allocate results as either base flow or high flow. At each site, geometric mean faecal indicator organism concentrations were significantly elevated at high flow compared to base flow. Stepwise regression modelling produced statistically significant models predicting geometric mean base and high-flow faecal indicator organism concentrations from land use variables (r2: 49.5-68.1%). The dominant predictor variable in each case was the proportion of built-up land in subcatchments, suggesting that this land use type, with associated sewage-related inputs, is a critical source of faecal indicator organisms in this drainage basin.


Subject(s)
Environmental Monitoring/statistics & numerical data , Feces , Geographic Information Systems , Water Pollutants/analysis , Biomarkers , Cities , Forecasting , Humans , Models, Theoretical , Recreation , Sewage , United Kingdom , Water Movements
20.
Water Res ; 39(14): 3320-32, 2005 Sep.
Article in English | MEDLINE | ID: mdl-16009396

ABSTRACT

'Natural' treatment systems such as wetlands and reed beds have been proposed as sustainable means of reducing fluxes of faecal indicator organisms (FIOs) to recreational and shellfish harvesting waters. This is because FIO fluxes to coastal waters from both point (effluent) and diffuse (catchment) sources can cause non-compliance with microbiological standards for bathing and shellfish harvesting waters. The Water Framework Directive requires competent authorities in the member states to manage both point and diffuse sources of FIOs in an integrated manner to achieve compliance with 'good' water quality as defined in a series of daughter Directives. This study was undertaken to investigate the relative sources of FIOs to the popular bathing waters around Clacton, UK. In this predominantly arable (mainly cereal cropping) farming area, the principal land use predictor, explaining 76% of the variance in geometric mean presumptive Escherichia coli concentration at sub-catchment outlets during the bathing season, was the proportion of built-up (i.e. urbanised) land in each sub-catchment. This new finding contrasts with earlier studies in livestock farming regions where the proportion of improved grassland has proven to be the strongest predictor of microbial concentration. Also novel in this investigation, a flood defence wall has been built creating a wetland area which discharges every tidal cycle. The wetland produces over 97% reduction in the flux and concentrations of FIOs to the marine recreational waters. Also, FIO concentrations in water draining through the wetland to the sea were similar to concentrations measured in six UK sewage treatment plant effluents subject to secondary (biological) treatment followed by UV disinfection.


Subject(s)
Disinfection/methods , Ecosystem , Sewage/microbiology , Water Microbiology , Water Pollution/analysis , Agriculture , Bathing Beaches/standards , Cities , Colony Count, Microbial , Disasters , Enterobacteriaceae/isolation & purification , Enterococcus/isolation & purification , Escherichia coli/isolation & purification , Feces/microbiology , Geography , Oceans and Seas , Population Dynamics , United Kingdom , Water Supply
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