Accounting for the three-dimensional distribution of Escherichia coli concentrations in pond water in simulations of the microbial quality of water withdrawn for irrigation
Artikel i vetenskaplig tidskrift, 2020

Evaluating the microbial quality of irrigation water is essential for the prevention of foodborne illnesses. Generic Escherichia coli (E. coli) is used as an indicator organism to estimate the microbial quality of irrigation water. Monitoring E. coli concentrations in irrigation water sources is commonly performed using water samples taken from a single depth. Vertical gradients of E. coli concentrations are typically not measured or are ignored; however, E. coli concentrations in water bodies can be expected to have horizontal and vertical gradients. The objective of this work was to research 3D distributions of E. coli concentrations in an irrigation pond in Maryland and to estimate the dynamics of E. coli concentrations at the water intake during the irrigation event using hydrodynamic modeling in silico. The study pond is about 22 m wide and 200 m long, with an average depth of 1.5 m. Three transects sampled at 50-cm depth intervals, along with intensive nearshore sampling, were used to develop the initial concentration distribution for the application of the environmental fluid dynamic code (EFDC) model. An eight-hour irrigation event was simulated using on-site data on the wind speed and direction. Substantial vertical and horizontal variations in E. coli concentrations translated into temporally varying concentrations at the intake. Additional simulations showed that the E. coli concentrations at the intake reflect the 3D distribution of E. coli in the limited pond section close to the intake. The 3D sampling revealed E. coli concentration hot spots at different depths across the pond. Measured and simulated 3D E. coli concentrations provide improved insights into the expected microbial water quality of irrigation water compared with 1D or 2D representations of the spatial variability of the indicator concentration.

3D distribution

E. coli

Irrigation

EFDC

Microbial water quality

Författare

Matthew D. Stocker

USDA Agricultural Research Service, Washington DC

Dong Jin Jeon

Korea Environment Institute

Ekaterina Sokolova

Chalmers, Arkitektur och samhällsbyggnadsteknik, Vatten Miljö Teknik

Hoonsoo Lee

Chungbuk National University

Moon S. Kim

USDA Agricultural Research Service, Washington DC

Yakov A. Pachepsky

USDA Agricultural Research Service, Washington DC

Water (Switzerland)

2073-4441 (ISSN)

Vol. 12 6 1708

Ämneskategorier

Vattenteknik

Oceanografi, hydrologi, vattenresurser

Miljövetenskap

DOI

10.3390/w12061708

Mer information

Senast uppdaterat

2020-09-17