Occurrence of Microbial Indicators and Clostridium perfringens in Wastewater, Water Column Samples, Sediments, Drinking Water, and Weddell Seal Feces Collected at McMurdo Station, Antarctica

Abstract

McMurdo Station, Antarctica, has discharged untreated sewage into McMurdo Sound for decades. Previous studies delineated the impacted area, which included the drinking water intake, by using total coliform and Clostridium perfringens concentrations. The estimation of risk to humans in contact with the impacted and potable waters may be greater than presumed, as these microbial indicators may not be the most appropriate for this environment. To address these concerns, concentrations of these and additional indicators (fecal coliforms, Escherichia coli, enterococci, coliphage, and enteroviruses) in the untreated wastewater, water column, and sediments of the impacted area and drinking water treatment facility and distribution system at McMurdo Station were determined. Fecal samples from Weddell seals in this area were also collected and analyzed for indicators. All drinking water samples were negative for indicators except for a single total coliform-positive sample. Total coliforms were present in water column samples at higher concentrations than other indicators. Fecal coliform and enterococcus concentrations were similar to each other and greater than those of other indicators in sediment samples closer to the discharge site. C. perfringens concentrations were higher in sediments at greater distances from the discharge site. Seal fecal samples contained concentrations of fecal coliforms, E. coli, enterococci, and C. perfringens similar to those found in untreated sewage. All samples were negative for enteroviruses. A wastewater treatment facility at McMurdo Station has started operation, and these data provide a baseline data set for monitoring the recovery of the impacted area. The contribution of seal feces to indicator concentrations in this area should be considered.

Freshwater Suspended Sediments and Sewage Are Reservoirs for Enterotoxin-Positive Clostridium perfringens

“…C. perfringens is commonly detected in surface waters contaminated with fecal pollution (3,5,38,39). A recent epidemiological study of freshwater beaches demonstrated adverse health effects when average C. perfringens levels were above 10 CFU/100 ml, illustrating that low levels of this indicator can be associated with a human health risk (57).…”

“…Others have repeatedly indicated the ability to recover C. perfringens spores from sediments long after initial fecal pollution inputs (17,27,39). The accumulation of particle-associated C. perfringens indicates the possibility of creating reservoirs of this potential pathogen in aquatic environments.…”

Comparison of the presence and partitioning behavior of indicator organisms and Salmonella spp. in an urban watershed

“…Clostridium perfringens spores have been recommended as potentially more useful surrogates for protozoan pathogens such as Cryptosporidium and Giardia and for monitoring impacts of discharges on receiving waters (Medema et al 1997b;Lisle et al 2004;Wiedenmann et al 2006). In the present study, C. perfringens concentrations were determined using the multiple-tube fermentation method with iron milk medium as substrate (St John et al 1982;AOAC 1995).…”

Type IV Pili and the CcpA Protein Are Needed for Maximal Biofilm Formation by the Gram-Positive Anaerobic Pathogen Clostridium perfringens

“…C. perfringens is also one of the most ubiquitous bacteria in natural environments and can be found anywhere mammals are present, including virtually all soils worldwide (26,35,47). In order to persist in the environment, C. perfringens, an obligate anaerobe, must have a means to deal with environmental stresses, such as oxygen, desiccation, and bactericidal compounds.…”