Sludge Watch ==> Exposure and risk - salmonella from biosolids

[Maureen Reilly]

1: Water Sci Technol. 2008;57(7):1061-1065.

Exposure and risk assessment of Salmonella in recycled residuals.Gerba CP, 
Castro-Del Campo N, Brooks JP, Pepper IL.
Department of Soil, Water and Environmental Science, The University of 
Arizona, 1177 E. Fourth Street, Tucson, AZ 85721, USA gerba at ag.arizona.edu.

The potential health effects of Salmonella found in wastewater residuals is 
dependent on the exposure of individuals to the organism. This paper 
provides a risk assessment for human infection from Salmonella due to direct 
contact with Class B biosolids, and from contact with Class A biosolids 
following regrowth of Salmonella. In addition, a risk assessment is provided 
for infection via airborne transport of bioaerosols from Class B biosolids 
and biosolids in which regrowth had occurred, to off-site communities. 
Results of the risk characterization imply that the risk of human infection 
from direct contact with Class B land applied residuals and subsequent 
ingestion is low. In contrast, the risk from direct contact with Class A 
residuals following regrowth is greater. Risks from airborne transport of 
Salmonella via bioaerosols away from a Class B land application site are 
also low. However, once again the risk from aerosols resulting from 
biosolids in which regrowth had occurred was greater. Based on these 
analyses, we conclude that it is highly unlikely that Salmonella infections 
will occur from land applied Class A or B residuals. However, risks become 
significant if Class A biosolids are stored anaerobically i.e. saturated, 
prior to land application. (c) IWA Publishing 2008.

PMID: 18441433