Salmonella spp. and Fecal Coliform Loads in Coastal Waters from a Point vs. Nonpoint Source of Pollution

Abstract

Coastal areas are often contaminated by the dissemination of pathogenic bacteria from terrestrial inputs. In this study, we compared fecal conforms (FC) and Salmonella spp.loads from a coastal Mediterranean river and from the submarine outfall of a coastal wastewater treatment station. A stratified sampling strategy was used to analyze storm events. Bacterial Boxes were estimated during a 16-mo period. Salmonella spp. loads from the river were high during storm events, and the annual loads were higher than those estimated from the coastal outfall. Bacterial loads from the river represented 3.0 x 10'6 FC yr ' and 6.9 X 10" ,Salmonella yr -1 , with at least 95% occurring during high waterflow (21 % of the year). Those from the submarine outfall represented 4.3 x 10'° FC yr -1 and 4.7 x 10'° Salmonella yr -1 , with a regular temporal discharge. Bacterial loads from the river were associated with small clay particles (<2 µm), which originate from different reservoirs. These particles-sediment-trapped bacterial accumulated in the river-bed during the lowest water levels in the downstream part of the river and were resuspended timing storm events. The quantitative relationship between both bacterial parameters vary depending on the source point of contamination. Salmonella spp. loads front the river are of great sanitary concern since high loads were recorded in summer (bathing activities) and autumn (oyster production and consumption). Our results should help water quality managers to define priorities to improve the bacterial quality of river discharges.

Salmonellae in the Environment

“…Their presence in water, therefore, indicates faecal contamination. Sewage effluents, agricultural run-off and direct deposit of faecal materials from wild animals and birds are the major sources of the bacteria in aquatic environments (Alcaide et al, 1984;Baudart et al, 2000;Johnson et al, 2003;Abulreesh et al, 2005). Salmonella species have been found in almost all types of aquatic environments that receive faecal contamination, that include drinking water (Bhatta et al, 2007), rivers (Pianetti et al, 1998;Polo et al, 1998;Polo et al, 1999;Dionisio et al, 2000;Lemarchand & Lebaron, 2003;Arvanitidou et al, 2005;Haley et al, 2009), lakes (Claudon et al, 1971;Arvanitidou et al, 1995;Sharma & Rajput, 1996), ponds (Shellenbarger et al, 2008), marine waters (Matinez-Urtaza et al, 2004a;Martinez-Urtaza et al, 2004b;Martinez-Urtaza & Liebana, 2005;Harakeh et al, 2006), run-off water (Claudon et al, 1971), treated and untreated wastewater (Ho & Tam, 2000;Melloul et al, 2002;Espigares et al, 2006, Mafu et al, 2009 worldwide.…”

“…Furthermore, Salmonella spp. were successfully detected in Spanish fresh and marine water that received faecal pollution in the absence of faecal indicators, as well as in aquatic environments with low degree of pollution (Pianetti et al, 1998;Baudart et al, 2000;Dionisio et al, 2000). Thus, the ability of faecal indicators to predict the presence of salmonellae in polluted environmental waters remains questionable, and the absence of faecal indicators is not always a reliable indication of the absence of Salmonella spp.…”

Use of 16S-23S rRNA Intergenic Spacer Region PCR and Repetitive Extragenic Palindromic PCR Analyses of Escherichia coli Isolates To Identify Nonpoint Fecal Sources

“…Fecal pollution is a serious environmental problem that affects many coastal and inland waters worldwide (1,3,4,14). Point source discharges such as raw sewage, storm water, combined sewer overflows, effluents from wastewater treatment plants, and industrial sources are considered the major contributors to fecal pollution (22).…”

Genetic characterization of <i>Salmonella</i> and <i>Shigella</i> spp. isolates recovered from water and riverbed sediment of the Apies River, South Africa

“…The quality and Baudart et al (2000) showed that Salmonella trapped in sediment particles accumulated in the riverbed during low water levels downstream of a river course and were re-suspended during storm events. In another study, the loads of Salmonella spp.…”