Publications by authors named "James P R Sorensen"

We investigated the seasonal prevalence of seven enteric viruses in groundwater-derived public water sources distributed across the dominant aquifers of England. Sampling targeted four periods in the hydrological cycle with typically varying microbial risks, as indicated using a decade of Escherichia coli prevalence data. Viruses were concentrated onsite by filtration of raw groundwater, and extracted nucleic acid (NA) was amplified by qPCR or RT-qPCR.

View Article and Find Full Text PDF

Faecal indicator organisms (FIOs) are limited in their ability to protect public health from the microbial contamination of drinking water because of their transience and time required to deliver a result. We evaluated alternative rapid, and potentially more resilient, approaches against a benchmark FIO of thermotolerant coliforms (TTCs) to characterise faecal contamination over 14 months at 40 groundwater sources in a Ugandan town. Rapid approaches included: in-situ tryptophan-like fluorescence (TLF), humic-like fluorescence (HLF), turbidity; sanitary inspections; and total bacterial cells by flow cytometry.

View Article and Find Full Text PDF

Fluorescent natural organic matter at tryptophan-like (TLF) and humic-like fluorescence (HLF) peaks is associated with the presence and enumeration of faecal indicator bacteria in groundwater. We hypothesise, however, that it is predominantly extracellular material that fluoresces at these wavelengths, not bacterial cells. We quantified total (unfiltered) and extracellular (filtered at < 0.

View Article and Find Full Text PDF

We explore in-situ fluorescence spectroscopy as an instantaneous indicator of total bacterial abundance and faecal contamination in drinking water. Eighty-four samples were collected outside of the recharge season from groundwater-derived water sources in Dakar, Senegal. Samples were analysed for tryptophan-like (TLF) and humic-like (HLF) fluorescence in-situ, total bacterial cells by flow cytometry, and potential indicators of faecal contamination such as thermotolerant coliforms (TTCs), nitrate, and in a subset of 22 samples, dissolved organic carbon (DOC).

View Article and Find Full Text PDF
Article Synopsis
  • Climate change and urbanization are increasing pressure on groundwater resources, with significant but not well-understood effects on groundwater quality.
  • A study analyzing over 9,000 samples found that local factors like dissolved inorganic chemistry, climate, and land use account for about 31% of the variability in dissolved organic carbon (DOC), while aquifer age adds another 16%.
  • The research predicts that urban land cover leads to a 19% rise in DOC and anticipates further increases in DOC due to changing precipitation and temperature, potentially lowering groundwater quality and raising water treatment costs.
View Article and Find Full Text PDF

Groundwater in sub-Saharan Africa supports livelihoods and poverty alleviation, maintains vital ecosystems, and strongly influences terrestrial water and energy budgets. Yet the hydrological processes that govern groundwater recharge and sustainability-and their sensitivity to climatic variability-are poorly constrained. Given the absence of firm observational constraints, it remains to be seen whether model-based projections of decreased water resources in dry parts of the region are justified.

View Article and Find Full Text PDF

We assess the use of fluorescent dissolved organic matter at excitation-emission wavelengths of 280nm and 360nm, termed tryptophan-like fluorescence (TLF), as an indicator of faecally contaminated drinking water. A significant logistic regression model was developed using TLF as a predictor of thermotolerant coliforms (TTCs) using data from groundwater- and surface water-derived drinking water sources in India, Malawi, South Africa and Zambia. A TLF threshold of 1.

View Article and Find Full Text PDF

Groundwater ecosystems remain poorly understood yet may provide ecosystem services, make a unique contribution to biodiversity and contain useful bio-indicators of water quality. Little is known about ecosystem variability, the distribution of invertebrates within aquifers, or how representative boreholes are of aquifers. We addressed these issues using borehole imaging and single borehole dilution tests to identify three potential aquifer habitats (fractures, fissures or conduits) intercepted by two Chalk boreholes at different depths beneath the surface (34 to 98 m).

View Article and Find Full Text PDF

A PHP Error was encountered

Severity: Warning

Message: fopen(/var/lib/php/sessions/ci_sessionk2tedjvi6gmault5h231s01udbtthkhd): Failed to open stream: No space left on device

Filename: drivers/Session_files_driver.php

Line Number: 177

Backtrace:

File: /var/www/html/index.php
Line: 316
Function: require_once

A PHP Error was encountered

Severity: Warning

Message: session_start(): Failed to read session data: user (path: /var/lib/php/sessions)

Filename: Session/Session.php

Line Number: 137

Backtrace:

File: /var/www/html/index.php
Line: 316
Function: require_once