Persistence of E. coli in Streambed Sediment Contaminated with Faeces from Dairy Cows, Geese, and Deer: Legacy Risks to Environment and Health

Abstract

Legacy stores of faecal pollution in streambed sediments can result in delayed impacts on environmental quality and human health if resuspended into the overlying water column. Different catchment sources of faecal pollution can contribute to a legacy store of microbial pollutants, with size of stores influenced by microbial die-off and faecal accrual rates in the streambed. The aim of this study was to use a mesocosm experiment to characterise the persistence of E. coli derived from faeces of dairy cows, deer, and geese once introduced to streambed sediment under different temperature regimes. The settling rate of solid constituents of faecal material into streambed sediment once delivered into an aquatic environment was also quantified. The persistence patterns of E. coli in streambed sediment were found to vary as a function of faecal source and temperature; die-off of E. coli in sediment contaminated with goose faeces was more rapid than in sediments contaminated with dairy cow or deer faeces. Goose faeces also recorded a more rapid settling rate of faecal particles through the water column relative to dairy cow and deer faeces, suggesting a more efficient delivery of E. coli to streambed sediments associated with this faecal source. Our findings provide new evidence to improve understanding of the potential longer-term risks to both the environment and public health posed by sediments when contaminated with livestock, wildlife, and wildfowl faeces.

Significant Factors for Modelling Survival of Escherichia coli in Lake Sediments

“…This provision of nutrients by the autoclave was consistent with the fact that the concentration of water-extractable DOC, which is an indicator of nutrients, was higher in the autoclaved sediments than in the untreated sediments ( Table S1 ). Under all conditions with the autoclaved sediments, E. coli did not grow at 10 °C, which is consistent with a previous study that reported that it could not grow at a cooler temperature (4 °C) in autoclaved sediment [ 39 ]. These cells of E. coli , which could not grow, may have been in a viable but non-culturable (VBNC) state, as reported at a low temperatures (<10 °C) [ 41 ].…”

“…The population change rates under the conditions with the autoclaved sediment of Lake A at 20 (−1.16 to 1.21 day −1 ) and 30 °C (−1.27 to 1.21 day −1 ) were higher than those at 10 °C (−1.14 to −0.12 day −1 ). The E. coli growth at above approximately 20 °C is consistent with a previous study reporting that E. coli can grow in autoclaved sediment [ 39 , 40 ]. Autoclaving sediments appear to provide nutrients that support the growth of E. coli and eliminate competitive and predatory coexisting microbes [ 40 ].…”

“…In this study, the effects of changes in the sediment factors on population change rates were evaluated by using E. coli strain K-12. However, previous studies reported that E. coli survival in the beach sand [ 20 ] and river sediment [ 39 ] environment depends on its strain and phylogenetic group. While phylogenetic groups A, B1, and D/E can survive longer in the sand environment than other groups [ 20 ], dependency of E. coli survival in lake sediment environments on its strains and phylogenetic group is still unknown, motivating further studies.…”

Integrated water quality dynamics in Wadi Hanifah: Physical, chemical, and biological perspectives

“…The presence of E . coli across multiple sites in Wadi Hanifah is a classic hallmark of fecal contamination, potentially due to sewage leakage or agricultural runoff [ 52 ] . This finding is alarming due to the associated risks of waterborne diseases.…”