William M. Buhay
University of Winnipeg
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Featured researches published by William M. Buhay.
Science of The Total Environment | 2013
Jules C. Carlson; Julie C. Anderson; Jennifer E. Low; Pascal Cardinal; Scott Mackenzie; Sarah A. Beattie; Renee J. Bennett; Stephanie S. Meronek; Rebecca P.A. Wilks; William M. Buhay; Charles S. Wong; Mark L. Hanson
Nutrient enrichment and loadings of pharmaceuticals and agrochemicals into freshwater systems are common concerns, especially for water bodies receiving wastewater inputs. In the rural communities of Morden and Winkler of Manitoba, Canada, sewage lagoons discharge their wastewater directly into Dead Horse Creek, a small tributary of the Red River that empties into Lake Winnipeg. This lagoon approach to managing rural wastewaters is common across the North American Prairies. Therefore, this study aimed to assess the hazards of lagoon treatment releases at this model site. This was done by characterizing the nutrients, organic micropollutants (i.e., pesticides, pharmaceuticals) and standard water quality parameters in the creek prior to and following lagoon discharge events over a number of years (2009-2011). Measured concentrations of nutrients were compared to regulatory expectations and micropollutants were assessed using hazard quotients. As expected, concentrations of nitrogen and phosphorus species were greatest in sites downstream of the sewage outfall immediately following discharge events. Pharmaceutical and agricultural chemicals were detected at concentrations between 0.5 and 90 ng/L. Detection frequencies and concentrations matched typical use patterns. Those compounds used predominately for human medicine were detected at downstream sites following discharge events, while those used in an agricultural setting were detected at relatively consistent levels over time at sites both upstream and downstream of the outfall location. Hazard quotients calculated for micropollutants of interest indicated minimal toxicological risk to aquatic biota in the creek, with only erythromycin and diazinon presenting a potential concern to aquatic algae and invertebrates. Concentrations of nutrients exceeded Canadian guideline thresholds during release, but returned to background levels once discharges ceased. Therefore, it is advisable that wastewater treatment and management strategies such as constructed wetlands and/or staggered releases be used in order to minimize the hazard posed by nutrient pulses in Dead Horse Creek and other similar systems.
Chemical Geology | 2008
Iain Robertson; Steven W. Leavitt; Neil J. Loader; William M. Buhay
Numerous studies have demonstrated the potential of stableisotopes in tree rings for quantitative terrestrial palaeoclimaticreconstruction (Ramesh et al., 1986; Heaton, 1999; Switsur andWaterhouse, 1998; McCarroll and Loader, 2004, 2005), but the earlywidespread application of isotope dendroclimatology has been hin-dered by laborious technical procedures that have, until recently,prevented wider application of this technique and severely con-strained progress. Developments in mass spectrometry (Preston andOwens, 1985, Barrie et al., 1995; Filot et al., 2006; Leuenberger andFilot, 2007) and sample preparation techniques (Leavitt and Danzer,1993; Loader et al., 1997; Brendel et al., 2000; Schulze et al., 2004;Rinneet al.,2005; Gaudinskiet al.,2005) haverevolutionisedthe fieldand enabled development of stable isotope chronologies with aheightened degree of replication (Gagen et al., 2007) and temporalrange(Treydteetal.,2006)thatwaspreviouslynotpracticalandrarelyobserved in any other proxy record outside of dendroclimatology.These and associated advances are reflected in the dramatic increasein the number and diversity of isotope tree ring papers presented atrecent international conferences. The thirty isotope tree ring paperspresented at the recent 7th International Conference on Dendrochro-nology(Beijing;11–17June2006)aretrulyinstarkcontrasttothetwodelivered at the 2nd International Workshop on Global Dendroclima-tology, 1980 (Long, 1982; Wigley, 1982). In this volume, the progressand advances in isotope dendroclimatology are critically reviewed inthe context of the initial work and aspirations of the early pioneers inthis field, and new directions and methodologies are explored.Dendroclimatology is an established field of palaeoclimatologyused in its scientific form since the early 20th Century. However, theapplication of stable isotope techniques to dendroclimatology is morerecent. Conceptually, the seed was planted when Urey (1947) statedthat “It seems probable that plant carbon compounds synthesised atdifferent temperatures may contain varying amounts of C
Chemical Geology | 1994
Thomas W. D. Edwards; William M. Buhay; Richard J. Elgood; H.B. Jiang
Abstract A revised method for oxygen isotope analysis of organic matter and water has been developed using resealable nickel pyrolysis bombs and a simplified operating procedure. Broad variations in the CO CO 2 ratio occur during the pyrolysis reaction, independent of the oxygen isotope composition of the CO2, suggesting that isotopic equilibrium between the two gases at high temperature (950°C) is retained as the bombs cool to room temperature. As a result, the δ18O-value of the sample can be obtained directly from the CO2, eliminating the need for nickel powder catalyst to enhance CO-CO2 conversion or the use of a spark discharge chamber to recover oxygen from CO. The method is well suited for rapid analysis of cellulose and other organic tissues and small (⩽ 5 μl) water samples.
Journal of Paleolimnology | 1998
William M. Buhay; Robert N. Betcher
Lake Agassiz water oxygen isotopic compositions inferred from sediment core organics and pore waters provide some additional insight into the paleohydrology of the Great Lakes and their drainage into the North Atlantic during the late glacial and early Holocene. Isotopically enriched Lake Agassiz water supports the hypothesis that high Huron Basin lake (Mattawa) phases, during the early Holocene (9600–9300 and 9100–8100 years BP) resulted from an influx of Lake Agassiz water and suggests that low lake (Stanley) phases (9800–9600, 9300–9100, 8100–7400 years BP) were influenced more by regional influxes of isotopically depleted glacial melt water. Eastward drainage of enriched early Lake Agassiz water supports an active Port Huron outlet between 11000 and 10500 years BP and also helps to explain the absence of an 18O depleted interval in North Atlantic foram records. This may be the result of a balance between the opposing isotopic effects of depleted Lake Agassiz water and lower sea surface temperatures on carbonate precipitation between 11000 and 10000 years BP.
Chemical Geology | 1997
J.E. Motz; Thomas W. D. Edwards; William M. Buhay
Abstract Addition of a simple evacuated collection device to nickel-tube pyrolysis bombs permits collection of the hydrogen gas produced during decomposition of water and other substances containing hydrogen. Tests using water samples spanning a broad range of 2 H/ 1 H ratios show that the method can be readily calibrated to yield precision comparable to that of the widely used zinc-reduction method. Preliminary results from pyrolysis of polyethylene foil, insect chitin, wood cellulose, peptide, and biotite mica (bound water) suggest that this modification of the nickel pyrolysis technique may have broad application, especially where both oxygen- and hydrogen-isotope compositions of the material are of interest.
PLOS ONE | 2017
Yadira Chinique de Armas; Mirjana Roksandic; Dejana Nikitović; Roberto Rodríguez Suárez; Nadine Kanik; Dailys García Jordá; William M. Buhay; Andrea S. Wiley
The general lack of well-preserved juvenile skeletal remains from Caribbean archaeological sites has, in the past, prevented evaluations of juvenile dietary changes. Canímar Abajo (Cuba), with a large number of well-preserved juvenile and adult skeletal remains, provided a unique opportunity to fully assess juvenile paleodiets from an ancient Caribbean population. Ages for the start and the end of weaning and possible food sources used for weaning were inferred by combining the results of two Bayesian probability models that help to reduce some of the uncertainties inherent to bone collagen isotope based paleodiet reconstructions. Bone collagen (31 juveniles, 18 adult females) was used for carbon and nitrogen isotope analyses. The isotope results were assessed using two Bayesian probability models: Weaning Ages Reconstruction with Nitrogen isotopes and Stable Isotope Analyses in R. Breast milk seems to have been the most important protein source until two years of age with some supplementary food such as tropical fruits and root cultigens likely introduced earlier. After two, juvenile diets were likely continuously supplemented by starch rich foods such as root cultigens and legumes. By the age of three, the model results suggest that the weaning process was completed. Additional indications suggest that animal marine/riverine protein and maize, while part of the Canímar Abajo female diets, were likely not used to supplement juvenile diets. The combined use of both models here provided a more complete assessment of the weaning process for an ancient Caribbean population, indicating not only the start and end ages of weaning but also the relative importance of different food sources for different age juveniles.
Radiocarbon | 2015
Mirjana Roksandic; William M. Buhay; Yadira Chinique de Armas; Roberto Rodríguez Suárez; Matthew Peros; Ivan Roksandic; Stephanie Mowat; Luis M Viera; Carlos Arredondo; Antonio Julián Martínez Fuentes; David G. Smith
Twelve accelerator mass spectrometry (AMS) radiocarbon dates from the shell-matrix site of Canimar Abajo (Matanzas, Cuba) are reported. Eleven were obtained directly from human bone collagen in burials and one was obtained from charcoal recovered from a burial context. The site stratigraphy presents two episodes of burial activity separated by a shell midden layer. The AMS dates fall into two compact clusters that correlate remarkably well with the stratigraphy. The older burial dates to between 1380–800 cal BC (2σ) and the younger one to between cal AD 360–950 (2σ). The AMS dates are compared to eight conventional 14 C dates previously obtained on shell and charcoal. One of the conventional dates on charcoal (5480–5380 cal BC; 2σ) has been reported as the oldest 14 C date in the Caribbean region; its context and reliability are clarified. The suite of AMS dates provides one of the most reliable chronometric dating of a cultural context during this timeframe in Cuba. The correlation of 14 C and stratigraphy establishes a solid chronology for investigating the important economic and ritual features of Canimar Abajo. DOI: 10.2458/azu_rc.57.18313
Quaternary Research | 1995
William M. Buhay; Thomas W. D. Edwards
Palaeogeography, Palaeoclimatology, Palaeoecology | 1992
John J. Clague; Rolf W. Mathewes; William M. Buhay; Thomas W. D. Edwards
Journal of Archaeological Science | 2015
Y. Chinique de Armas; William M. Buhay; R. Rodríguez Suárez; Sheahan Bestel; David G. Smith; Stephanie Mowat; Mirjana Roksandic