Modeling enteric pathogen transmission through the land surface: A comparison of urban slum and rural villages in southern India.
Abstract: The rate of
enteric diseases is high in Indian rural villages and urban slums, contributing to
malnutrition and death primarily in children under five. These faecal-orally transmitted
diseases are perpetuated through the mismanagement of sewage and feces leading to
pathogen contamination of drinking water and direct human contact with pathogens in the
soil environment. Soil can act ... read moreas a reservoir for pathogens, and in order to trace the
path of transmission from excretion by one host to consumption by another the effect of
soil on pathogens must be understood. However, recent studies emphasize that complex
conditions within the subsurface make it challenging to predict pathogen fate and
transport. In this 18 month long study, drinking water quality, enteric disease rates,
and soil properties were monitored in three rural villages and two urban slums in
southern India to observe the relationship between these parameters. In addition, soil
properties were used to develop fate and transport models for E. coli and
Cryptosporidium to give a preliminary assessment of the soil's ability to house enteric
pathogens. Statistical analysis revealed that clay content may impact the nearby
household enteric disease rates. The soil total soluble organics and soil ammonia
content may influence the nitrite concentration within nearby drinking water while soil
porosity, soil clay content, and soil ammonia concentration may impact the nearby
drinking water fecal coliform counts. Fate and transport models predicted higher
pathogen concentrations near where public drinking water distribution pipes lie within
the ground. Analysis also showed urban groundwater to be more in danger of pathogen
contamination than rural groundwater due to a faster pore water velocity. Future
research should assess the relationship between the identified soil properties and
drinking water nitrate concentrations and fecal coliform counts within controlled
laboratory experiments. Possible interventions should focus on lining sewage ditches
with concrete in rural villages and moving sewage runoff areas away from borewells and
drinking water pipes.
Thesis (M.S.)--Tufts University, 2012.
Submitted to the Dept. of Civil Engineering.
Advisor: Elena Naumova.
Committee: Stephen Chapra, and Tim Ford.
Keywords: Environmental health, Environmental engineering, and Public health.read less