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Causal connections between water quality and land use in a rural tropical island watershed: rural tropical island watershed analysis.

Ragosta G, Evensen C, Atwill ER, Walker M, Ticktin T, Asquith A, Tate KW - Ecohealth (2010)

Bottom Line: Each 1% decrease in riparian canopy cover was associated with a 4.6 most probable number (MPN)/100 ml increase of the geometric mean of Enterococcus in stream water (P < 0.05).Each unit decrease in salinity (ppt) was associated with an increase of Enterococcus by 68.2 MPN/100 ml in-stream water geometric mean concentrations (P < 0.05).Reducing riparian canopy cover is associated with Enterococcus increases in stream water, suggesting that decreasing riparian vegetation density could increase fecal bacteria surface runoff.

View Article: PubMed Central - PubMed

Affiliation: Surfing Medicine International 501(c)(3), 5-5785A Kuhio Highway, Hanalei, HI 96714, USA. surfingmedicine@gmail.com

ABSTRACT
We examined associations between riparian canopy cover, presence or absence of cattle, rainfall, solar radiation, month of year, dissolved oxygen, turbidity, salinity, and Enterococcus concentrations in riparian surface soils with Enterococcus geometric mean in-stream water concentrations at Waipā watershed on the north side of the Hawaiian island Kaua'i. Each 1% decrease in riparian canopy cover was associated with a 4.6 most probable number (MPN)/100 ml increase of the geometric mean of Enterococcus in stream water (P < 0.05). Each unit decrease in salinity (ppt) was associated with an increase of Enterococcus by 68.2 MPN/100 ml in-stream water geometric mean concentrations (P < 0.05). Month of year was also associated with increases in stream water Enterococcus geometric mean concentrations (P < 0.05). Reducing riparian canopy cover is associated with Enterococcus increases in stream water, suggesting that decreasing riparian vegetation density could increase fecal bacteria surface runoff.

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Related in: MedlinePlus

Map of Hawaiian Islands.
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Related In: Results  -  Collection


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Fig1: Map of Hawaiian Islands.

Mentions: U.S. Environmental Protection Agency (USEPA) recommends testing for Enterococcus for fresh and marine waters, since presence of Enterococcus has been shown to be directly correlated with gastrointestinal illness rates associated with recreational contact (USEPA, 1986). Byappanahalli and Fujioka (2004) stated that elevated Enterococcus in tropical island surface waters that exceeded USEPA standards was due to runoff from soil that contained free-living cells, producing false-positive results with respect to implied contamination by feces of warm-blooded animals and the microbiological safety of water supplies. The water quality criterion for Enterococci is a geometric mean concentration of 33 of the most probable number (MPN)/100 ml in fresh water, and 35 MPN/100 ml in marine water, of five samples collected over a 30-day period. We examined relationships between Enterococcus water concentrations and land use at Waipā watershed on the Hawaiian Island of Kaua’i (Fig. 1) for monitoring and regulatory enforcement based upon a geometric mean of multiple sample collections per month. Evaluation of Enterococcus as a reliable indicator of surface water fecal contamination is required to establish that this monitoring metric is effective for protecting human health and guiding implementation of water quality management practices.Figure 1


Causal connections between water quality and land use in a rural tropical island watershed: rural tropical island watershed analysis.

Ragosta G, Evensen C, Atwill ER, Walker M, Ticktin T, Asquith A, Tate KW - Ecohealth (2010)

Map of Hawaiian Islands.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2914289&req=5

Fig1: Map of Hawaiian Islands.
Mentions: U.S. Environmental Protection Agency (USEPA) recommends testing for Enterococcus for fresh and marine waters, since presence of Enterococcus has been shown to be directly correlated with gastrointestinal illness rates associated with recreational contact (USEPA, 1986). Byappanahalli and Fujioka (2004) stated that elevated Enterococcus in tropical island surface waters that exceeded USEPA standards was due to runoff from soil that contained free-living cells, producing false-positive results with respect to implied contamination by feces of warm-blooded animals and the microbiological safety of water supplies. The water quality criterion for Enterococci is a geometric mean concentration of 33 of the most probable number (MPN)/100 ml in fresh water, and 35 MPN/100 ml in marine water, of five samples collected over a 30-day period. We examined relationships between Enterococcus water concentrations and land use at Waipā watershed on the Hawaiian Island of Kaua’i (Fig. 1) for monitoring and regulatory enforcement based upon a geometric mean of multiple sample collections per month. Evaluation of Enterococcus as a reliable indicator of surface water fecal contamination is required to establish that this monitoring metric is effective for protecting human health and guiding implementation of water quality management practices.Figure 1

Bottom Line: Each 1% decrease in riparian canopy cover was associated with a 4.6 most probable number (MPN)/100 ml increase of the geometric mean of Enterococcus in stream water (P < 0.05).Each unit decrease in salinity (ppt) was associated with an increase of Enterococcus by 68.2 MPN/100 ml in-stream water geometric mean concentrations (P < 0.05).Reducing riparian canopy cover is associated with Enterococcus increases in stream water, suggesting that decreasing riparian vegetation density could increase fecal bacteria surface runoff.

View Article: PubMed Central - PubMed

Affiliation: Surfing Medicine International 501(c)(3), 5-5785A Kuhio Highway, Hanalei, HI 96714, USA. surfingmedicine@gmail.com

ABSTRACT
We examined associations between riparian canopy cover, presence or absence of cattle, rainfall, solar radiation, month of year, dissolved oxygen, turbidity, salinity, and Enterococcus concentrations in riparian surface soils with Enterococcus geometric mean in-stream water concentrations at Waipā watershed on the north side of the Hawaiian island Kaua'i. Each 1% decrease in riparian canopy cover was associated with a 4.6 most probable number (MPN)/100 ml increase of the geometric mean of Enterococcus in stream water (P < 0.05). Each unit decrease in salinity (ppt) was associated with an increase of Enterococcus by 68.2 MPN/100 ml in-stream water geometric mean concentrations (P < 0.05). Month of year was also associated with increases in stream water Enterococcus geometric mean concentrations (P < 0.05). Reducing riparian canopy cover is associated with Enterococcus increases in stream water, suggesting that decreasing riparian vegetation density could increase fecal bacteria surface runoff.

Show MeSH
Related in: MedlinePlus