Attenuation of effluent‐derived faecal microbes in grass buffer strips

Collins, Rob; Donnison, A.; Ross, Colleen; McLeod, Malcolm

doi:10.1080/00288233.2004.9513621

Cited by 27 publications

(31 citation statements)

References 8 publications

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“…At present c. 50% of the stream is fenced, but we have frequently observed stock within these fenced areas, near the stream. Dense vegetation within fenced riparian areas has the potential to reduce faecal pathogen input in surface run-off, provided the flow rates are sufficiently low (Collins et al 2004). Another positive outcome of this might be increased stream shading from riparian plants, resulting in lower water temperatures and improved DO during summer as a result of reduced photosynthetic and heterotrophic respiration (Wilcock & Nagels 2001).…”

Section: Faecal Pollutionmentioning

confidence: 99%

Land‐use impacts and water quality targets in the intensive dairying catchment of the Toenepi Stream, New Zealand

Wilcock

Monaghan

Quinn

et al. 2006

New Zealand Journal of Marine and Freshwater Research

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Water quality monitoring in Toenepi Stream, New Zealand, started in 1995 in a study of dairy farming influences on lowland stream quality and has continued since then with brief interruptions. Surveys have provided information about changes in farm and soil management practices as they relate to environmental sustainability. Although average water quality in Toenepi Stream has changed little during 1995-2004, there have been some notable improvements. Water clarity measured by black disc has improved from 0.6m to 1.5m, and median ammonia-N and nitrate-N concentrations have declined by 70% and 57%, respectively. The frequency and magnitude of extreme concentrations have declined-most notably for nitrogen (N) forms, which also had decreased mean values. Specific yields for suspended solids (SS) and phosphorus (P) forms in 2002-04 were 47-67% of 1995-97 values, mainly because of lower water yields. Reduced specific yields for N forms in 2002-04 (34-37% of 1995-97 yields) were also attributable to lower mean concentrations in stream water. Faecal bacteria concentrations have not abated and are on average 2-3 times recommended guideline values for contact recreation. Fewer dairy farms and an increased proportion irrigating dairyshed effluent to land, rather than discharging it to the stream via twopond systems, were likely causes of improvement in water quality. Water quality targets were developed for Toenepi Stream to achieve contact recreation criteria for the Piako River (downstream) and for intrinsic habitat values for Toenepi Stream. A range of mitigation measures has been formulated to meet these targets, but substantial uptake of sustainable farming practices is needed to improve water quality in Toenepi Stream.

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Section: Faecal Pollutionmentioning

confidence: 99%

Land‐use impacts and water quality targets in the intensive dairying catchment of the Toenepi Stream, New Zealand

Wilcock

Monaghan

Quinn

et al. 2006

New Zealand Journal of Marine and Freshwater Research

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“…While there is significant evidence of the direct impact of cattle on rural waterways (6,9,11,31), sheep have nevertheless been implicated as contributors to bacterial indicator and pathogen loadings in rivers and streams (8,10,18,20). It has been suggested that the total number of Escherichia coli per hectare of pasture are higher for sheep than for cattle (30).…”

mentioning

confidence: 99%

Survival of Escherichia coli , Enterococci, and Campylobacter spp. in Sheep Feces on Pastures

Moriarty

Mackenzie

Karki

et al. 2011

Appl Environ Microbiol

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The survival of enteric bacteria in 10 freshly collected sheep fecal samples on pastures was measured in each of four seasons. Ten freshly collected feces were placed on pasture, and concentrations of Escherichia coli, enterococci, and Campylobacter spp. were monitored until exhaustion of the fecal samples. In all four seasons, there was an increase in enterococcal concentrations by up to 3 orders of magnitude, with peak concentrations recorded between 11 and 28 days after deposition. E. coli concentrations increased in three out of four seasons by up to 1.5 orders of magnitude, with peak concentrations recorded between 8 and 14 days after deposition. The apparent growth of E. coli and enterococci was strongly influenced by the initial water content of the feces and the moisture gained during periods of rehydration following rainfalls. Conversely, the results suggested that dehydration promoted inactivation. Campylobacter spp. did not grow and were rapidly inactivated at a rate that tended to be faster at higher temperatures. Pulsed-field gel electrophoresis (PFGE) of a selection of Campylobacter spp. suggested that these survival data are applicable to a range of Campylobacter spp., including the most frequently isolated PFGE genotype from sheep in New Zealand, and to genotypes previously observed to cause disease in humans. The results of this study are currently being incorporated into a fecal microbe reservoir model that is designed to assist water managers' abilities to estimate microbial loads on pastures grazed by sheep, including the influence of factors such as rainfall and temperature.

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“…In a study of pig slurry flowing down a slope, it was reported that all of the bacteria were absorbed and retained by the soil under relatively dry antecedent conditions (9). In contrast, studies with saturated soils often show poor removal of bacteria (4,5). This can be attributed, in part, to a lack of infiltration, which limits interaction of runoff with the soil matrix (1,3).…”

mentioning

confidence: 99%

Interaction of Escherichia coli and Soil Particles in Runoff

Muirhead

Collins

Bremer

2006

Appl Environ Microbiol

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A laboratory-scale model system was developed to investigate the transport mechanisms involved in the horizontal movement of bacteria in overland flow across saturated soils. A suspension of Escherichia coli and bromide tracer was added to the model system, and the bromide concentration and number of attached and unattached E. coli cells in the overland flow were measured over time. Analysis of the breakthrough curves indicated that the E. coli and bromide were transported together, presumably by the same mechanism. This implied that the E. coli was transported by advection with the flowing water. Overland-flow transport of E. coli could be significantly reduced if the cells were preattached to large soil particles (>45 m). However, when unattached cells were inoculated into the system, the E. coli appeared to attach predominantly to small particles (<2 m) and hence remained unattenuated during transport. These results imply that in runoff generated by saturation-excess conditions, bacteria are rapidly transported across the surface and have little opportunity to interact with the soil matrix.The transport of microorganisms from agricultural land into waterways can have detrimental effects on water quality and human health (10,18,28,29). To develop robust strategies to control the passage of microorganisms to waterways, a good understanding of the transport mechanisms involved is required. In a study of pig slurry flowing down a slope, it was reported that all of the bacteria were absorbed and retained by the soil under relatively dry antecedent conditions (9). In contrast, studies with saturated soils often show poor removal of bacteria (4, 5). This can be attributed, in part, to a lack of infiltration, which limits interaction of runoff with the soil matrix (1, 3).A further important factor in determining bacterial transport in overland flow is the state in which the bacteria occur, with different transport mechanisms postulated for bacteria attached to soil particles, present in flocs of cells, or occurring as single cells (11,16,28). It has been calculated that bacteria would need to be attached to soil particles Ͼ63 m in diameter to settle out of overland flow and would need to be in large flocs Ͼ500 m in diameter before they could be filtered out by grasses (11). In studies with artificial cowpats under simulated rainfall conditions, it was found that Escherichia coli cells were not eroded in flocs and that only 8% were attached to particles (21). These findings imply that E. coli eroded from cowpats during rainfall events would, under saturation-excess conditions, be rapidly transported over the soil surface unless it can attach to large soil particles during the transport process.There have been numerous studies on the attachment of bacteria to particles in marine waters, but only a small number with freshwater systems (8). In storm water from urban land, fecal indicator bacteria were adsorbed predominantly to fine clay particles (Ͻ2 m) (6). In another study with urban storm water, 83% of fecal coliforms...

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Attenuation of effluent‐derived faecal microbes in grass buffer strips

Cited by 27 publications

References 8 publications

Land‐use impacts and water quality targets in the intensive dairying catchment of the Toenepi Stream, New Zealand

Land‐use impacts and water quality targets in the intensive dairying catchment of the Toenepi Stream, New Zealand

Survival of Escherichia coli , Enterococci, and Campylobacter spp. in Sheep Feces on Pastures

Interaction of Escherichia coli and Soil Particles in Runoff

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