ABSTRACT
Recreational bathing waters are complex systems with diverse inputs from multiple anthropogenic and zoogenic sources of faecal contamination. Faecal contamination is a substantial threat to water quality and public health. Here we present a comprehensive strategy to estimate the contribution of faecal indicator bacteria (FIB) from different biological sources on two at-risk beaches in Dublin, Ireland. The daily FIB loading rate was determined for three sources of contamination: a sewage-impacted urban stream, dog and wild bird fouling. This comparative analysis determined that the stream contributed the highest daily levels of FIB, followed by dog fouling. Dog fouling may be a significant source of FIB, contributing approximately 20 % of E. coli under certain conditions, whereas wild bird fouling contributed a negligible proportion of FIB (<3 %). This study demonstrates that source-specific quantitative microbial source apportionment (QMSA) strategies are vital to identify primary public health risks and target interventions to mitigate faecal contamination.
Subject(s)
Environmental Monitoring , Feces , Feces/microbiology , Environmental Monitoring/methods , Animals , Ireland , Bathing Beaches , Water Microbiology , Water Pollution/statistics & numerical data , Water Pollution/analysis , Dogs , Sewage/microbiology , Escherichia coli/isolation & purification , Water Quality , Bacteria/isolation & purification , Birds/microbiologyABSTRACT
El objetivo del trabajo fue presentar y analizar los datos de contaminación fecal canina y parasitaria en plazas y veredas de Buenos Aires obtenidos entre 1991 y 2006 por la Cátedra Parasitología General (Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires). Se censaron las heces en varias plazas cada año en un único día entre 1991-2006. A partir del año 2000 se censaron heces en veredas circundantes. En cada plaza se seleccionaron al azar 30 heces frescas que se conservaron en formol 5% para su análisis parasitológico por el método de flotación de Willis con solución saturada de ClNa. Los 51 censos presentaron una mediana de heces de 288; un 82% de las heces se observaron en los canteros de tierra o pasto. La contaminación fecal en las plazas fue mayor en el período 2000-06 que en el anterior (p = 0.0000). La contaminación fecal de las plazas aumentó con la densidad humana en las manzanas lindantes (p = 0.0076). Las veredas mostraron un patrón inverso, ya que la contaminación fecal fue mayor en las áreas menos densamente pobladas (p = 0.0000). Se detectaron parásitos en un número variable de las heces colectadas en todas las plazas. Los géneros más frecuentes fueron Ancylostoma (20.47%), Trichuris (2.59%) y Toxocara (1.70%). Nuestros resultados indican un aumento en la contaminación fecal de las plazas, posiblemente asociado con el aumento del número de perros en la ciudad combinado con las deficiencias en la implementación y el seguimiento de las medidas de control.
The aim of this study was to provide data on canine fecal and helminthic contamination from parks and sidewalks in Buenos Aires City, collected by the Laboratory of General Parasitology, School of Sciences, University of Buenos Aires. A census of dog feces was performed in 1-11 parks per year between 1991 and 2006, a single day each year. In the period 2000-2006, the census included feces on sidewalks surrounding the park. Thirty fresh fecal samples were randomly collected from each park to determine the presence of helminth eggs and fixed with 5% formalin until diagnosis by the Willis' flotation method with a saturated solution of NaCl. The 51 censuses showed a median of 288 feces/park and 82% of the feces were collected from grass or bare-ground areas. Fecal contamination in parks was higher between 2000/06 than in the previous period (p<0.0000), and it increased with increasing human density on sidewalks surrounding the park (p=0.0076). The sidewalks showed a inverse pattern, with larger fecal contamination in the lesser densely populated areas (p=0.0000). All parks showed infected samples. The most frequent helminth genera were Ancylostoma (20.47%), Trichuris (2.59%) and Toxocara (1.70%). Our results indicated that an increase in dog number in addition to deficient public control policies accounted for the increase in dog fouling in public spaces of the city.
