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William B. Samuels

Publications and source records attributed to William B. Samuels.

15 recordsLinked to original sources
USGS2015

Fecal indicator and pathogenic bacteria and their antibiotic resistance in alluvial groundwater of an irrigated agricultural region with dairies

Surveys of microbiological groundwater quality were conducted in a region with intensive animal agriculture in California, USA. The survey included monitoring and domestic wells in eight concentrated animal feeding operations (CAFOs) and 200 small (domestic and community supply district) supply wells across the region. Campylobacter was not detected in groundwater, whereas Escherichia coli O157:H7 and Salmonella were each detected in 2 of 190 CAFO monitoring well samples. Nonpathogenic generic E. coli and Enterococcus spp. were detected in 24.2% (46/190) and 97.4% (185/190) groundwater samples from CAFO monitoring wells and in 4.2% (1/24) and 87.5% (21/24) of CAFO domestic wells, respectively. Concentrations of both generic E. coli and Enterococcus spp. were significantly associated with well depth, season, and the type of adjacent land use in the CAFO. No pathogenic bacteria were detected in groundwater from 200 small supply wells in the extended survey. However, 4.5 to 10.3% groundwater samples were positive for generic E. coli and Enterococcus. Concentrations of generic E. coli were not significantly associated with any factors, but concentrations of Enterococcus were significantly associated with proximity to CAFOs, seasons, and concentrations of potassium in water. Among a subset of E. coli and Enterococcus isolates from both surveys, the majority of E. coli (63.6%) and Enterococcus (86.1%) isolates exhibited resistance to multiple (≥3) antibiotics. Findings confirm significant microbial and antibiotic resistance loading to CAFO groundwater. Results also demonstrate significant attenuative capacity of the unconfined alluvial aquifer system with respect to microbial transport.

California↗
USGS2015

The Open Water Data Initiative: Water information for a thirsty nation

Initial efforts of the Open Water Data Initiative have focused on three use cases covering flooding, drought, and contaminant spill response, with a goal of identifying critical water data resources and making them more accessible. Significant progress has been made in the past year, although much remains to be done.

Water Resources Impact↗
USGS1984

Calculations of seabird population recovery from potential oilspills in the mid-Atlantic region of the United States

Calculations were made of herring gull and common tern population recovery from potential oilspill damage in the U.S. mid-Atlantic Outer Continental Shelf (OCS) oil leasing area. Population recovery was examined using a density-dependent age-specific life history table for each species. Both a deterministic and a stochastic approach were used in the calculations. In the deterministic approach, it was assumed that an oilspill contact to a seabird colony had occurred. Using the density-dependent model, population recovery was calculated for several different mortality scenarios. Assuming that all age classes suffer 95% mortality from an oilspill contact, a worst case scenario, it was estimated that the herring gull and common tern populations could recover to their pre-spill levels in approximately 45 years and more than 100 years, respectively. In the stochastic approach, the probabilities of oilspill contacts to these seabird colonies were calculated using an oilspill trajectory analysis model. Oilspill contacts to these colonies were simulated during the expected 30 year active life of the lease area. For each lease lifetime, the number of oilspill contacts to a seabird colony was sampled from a Poisson distribution and assigned randomly on a seasonal basis. This analysis indicated that the oilspill risks from the development of proposed lease tracts in the mid-Atlantic region pose minimal risk (3–5%) of severe population reduction for both herring gulls and common terns. If the oilspill risks from tanker transportation of crude oil imports are included along with the proposed lease tracts, then the risks of severe population reduction are increased to approximately 10% for herring gulls and 18% for common terns.

Mid-Atlantic region↗
USGS1980

An oilspill risk analysis for the Kodiak Island (proposed sale 46) Outer Continental Shelf lease area

An oilspill risk analysis was conducted to determine the relative environmental hazards of developing oil in different regions of the Kodiak Island Outer Continental Shelf (OCS) lease area. The study analyzed the probability of spill occurrences, likely paths of oil slicks, and locations of resources vulnerable to spilled oil. The analysis included estimates of the time between spill occurrence and contact with resources. The combined results yielded estimates of the overall risks associated with development of the proposed lease area. Assuming that oil will be found in all parts of the lease area, and depending upon the routes chosen to transport oil from OCS platforms to the shore, the leasing of the tracts proposed for OCS Sale 46 will result in an expected number of 1.1 spills. The estimated probability that land will be contacted by one or more oilspills which have been at sea less than 30 days is 0.43.

Alaska↗
USGS1980

An oilspill risk analysis for the Central and Northern California (proposed Sale 53) Outer Continental Shelf lease area

An oilspill risk analysis was conducted to determine the relative environmental hazards of developing oil in different regions of the Central and Northern California Outer Continental Shelf (OCS) lease area. The study analyzed the probability of spill occurrences, likely paths of oil slicks, and locations of resources vulnerable to spilled oil. The analysis included estimates of the time between spill occurrence and contact with resources. The combined results yielded estimates of the overall risks associated with development of the proposed lease area. Assuming that oil will be found in all parts of the lease area, and depending upon the routes chosen to transport oil from OCS platforms to the shore, the leasing of the tracts proposed for OCS Sale 53 will, depending upon how oil is transported to shore, result in an expected 2.0 to 3.1 spills. The estimated probability that land will be contacted by one or more oilspills which have been at sea less than 30 days is between 0.49 and 0.86.

California↗
USGS1980

Oilspill analysis for the Cook Inlet and Shelikof Strait (proposed sale 60) Outer Continental Shelf lease area

An oilspill risk analysis was conducted to determine the relative environmental hazards of developing oil in different regions of the Cook Inlet and Shelikof Strait (Proposed Sale 60) Outer Continental Shelf (OCS) lease area. The probability of spill occurrences, likely movement of oil slicks, and locations of resources vulnerable to spilled oil were analyzed. The times between spill occurrence and contact with various resources were estimated. The combined results yielded estimates of the overall risks associated with development of the proposed lease area. Assuming that oil will be found in all 153 proposed tracts of the lease area, and depending upon the routes chosen to transport oil from OCS platforms to the shore, the leasing of the tracts proposed for OCS Sale 60 will result in an expected 4.0 oilspills. The estimated probability that land will be contacted by one or more oilspills that have been at sea less than 30 days is 0.96.

Alaska↗
USGS1979

An oilspill risk analysis for the Northern Gulf of Alaska (proposed sale 55), Outer Continental Shelf lease area

An oilspill risk analysis was conducted to determine the relative environmental hazards of developing oil in different regions of the Northern Gulf of Alaska Outer Continental Shelf lease area. The study analyzed the probability of spill occurrences, likely paths of the spilled oil, and locations of resources vulnerable to spilled oil. The combined results yielded estimates of the overall oilspill risks associated with development of the proposed lease area. The analysis implicitly includes estimates of weathering rates and slick dispersion and an indication of the possibility of mitigating effects by cleanup efforts. The leasing of the tracts proposed for Sale 55 will result in an expected number of 2.8 spills. The estimated probability that land will be contacted by one or more spills within 30 days is 0.84; however, this probability varies greatly for the different targets and different contact times.

Alaska↗