Manitoba, Canada
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Sheppard S.C.,ECOMatters Inc. | Stephenson G.L.,Stantec Inc.
Bulletin of Environmental Contamination and Toxicology | Year: 2012

Discrepancies about probable no effect concentrations (PNEC) for uranium in soils may be because toxicity tests used freshly contaminated soils. This study used 3 soils amended with a range of uranium concentrations 10 years previously. The toxicity tests with northern wheatgrass (Elymus lanceolatus); earthworm (Eisenia andrei) were not affected below ~1,000 mg U kg -1, and the soil arthropod Folsomia candida was not affected below ~350 mg U kg -1. Survival of Orthonychiurus folsomi was diminished 20% (EC 20) by ~85-130 mg U kg -1, supporting a PNEC in the range of 100-250 mg U kg -1 as derived previously. © 2011 Springer Science+Business Media, LLC.

Sheppard S.C.,ECOMatters Inc.
Human and Ecological Risk Assessment | Year: 2011

Soil solid/liquid partition coefficients (Kd) are commonly used in quantitative environmental assessments as a means to predict retention of contaminant metals and radionuclides in soils. There are Kd data for most elements in the literature, and they can be measured for specific sites. However, there is also a need for robust, defensible relationships to predict the variation in Kd as a function of soil characteristics. This article reports relationships for As, Cd, Ce, Cl, Co, Cr, Cs, Cu, Fe, Ho, I, La, Mn, Mo, Nb, Nd, Ni, Np, Pa, Pb, Pu, Ra, Sb, Se, Sm, Sn, Sr, Tc, Th, Tl, Tm, U, W, and Yb, most based on a wide range of soil properties. Soil pH, clay content, and organic carbon content were the independent variables considered in all cases, and methodology variables were invoked for Cs, Mn, and Ni. The underlying Kd data were considered representative of steady state conditions: most were measured by desorption of the indigenous element at realistic field moisture contents. The equations, developed by forward or backward stepwise regression, were all statistically highly significant. Estimates from the equations were compared to data for seven site-specific soils and generally were within 95th percentile bounds. © Taylor & Francis Group, LLC.

A recent study measured transfer factors for 49 elements in hunter-killed Whitetail deer (Odocoileus virginianus), using concentrations in the stomach content as the substrate/denominator to compute muscle/vegetation concentration ratios (CRm-stomach) and daily fractional transfer factors (Ff). Using the stomach content ensured an accurate representation of what the deer ate, except that it was limited in time to the vegetation selected by the animal just before it was killed. Here, two alternatives are considered, one where the feed is represented by samples of 21 different vegetation types that deer may have eaten in the area (CRm-plant), and the other is using soil concentration in the region as the denominator (CRm-soil). The latter is the formulation used in the ERICA tool, and other sources, for risk assessment to non-human biota. Across elements, (log) concentrations in all the media were highly correlated. The stomach contents had consistently higher ash and rare earth element concentrations than the sampled (and washed) vegetation and this was attributed to soil or dust ingestion. This lends credence to the use of soil-based CRm-soil values, despite (or more accurately because of) the inclusive yet gross simplicity of the approach. However, it was clear that variation of CRm-soil values was larger than for CRm-stomach or CRm-plant, even if soil load on vegetation was included in the latter values. It was also noted that the variation in CRm-soil computed from the product of CRm-plant and CRplant-soil (where CRplant-soil is the plant/soil concentration ratio) was somewhat larger than the variation inherent in CRm-soil data. Thus it is reasonable to estimate CRm-soil from CRm-plant and CRplant-soil if observed CRm-soil values are not available, but this introduces further uncertainty. © 2012 Elsevier Ltd.

Sheppard S.C.,ECOMatters Inc. | Long J.M.,ECOMatters Inc. | Sanipelli B.,ECOMatters Inc.
Journal of Environmental Radioactivity | Year: 2010

Recent reviews have established benchmark values for transfer factors that describe radionuclide transfer from plants to animal food product such as milk, eggs and meat. They also illustrate the paucity of data for some elements and some food products. The present study quantified transfer data using indigenous elements measured in dairy, poultry and other livestock farms in Canada. Up to 62 elements are reported, with particular emphasis on iodine (I) because of the need to accurately assess the behaviour of 129I from disposal of nuclear fuel waste. There was remarkable agreement with the literature values, and for many elements the present study involved many more observations than were previously available. Perhaps the most important observation was that product/substrate concentration ratios (CR) were quite consistent across species, whereas the traditional fractional transfer factors (TF, units of d kg-1 or d L-1) necessarily vary with body mass (feed intake). This suggests that for long-term assessments, it may be advisable to change the models to use CR rather than TF. © 2010 Elsevier Ltd.

Sheppard S.C.,ECOMatters Inc. | Bittman S.,Agriculture and Agri Food Canada
Atmospheric Environment | Year: 2015

Ammonia (NH3) emissions from agriculture to the atmosphere, along with emissions of other pollutants from a variety of sources, are of concern to agriculture worldwide. National emissions from agricultural sources in Canada are linked to domestic consumption and export demand for agricultural products. The onus to limit emissions is often directed to the producers, but the marketplace and consumer are also responsible for the environmental impact of their choices. This objective of this study was to quantitatively link agricultural NH3 emissions to per person consumption of food and protein and to agricultural exports from Canada. There are substantial differences in the NH3 emissions per unit consumed protein among the various food types. As a result, shifts in the Canadian diet have had a large impact on relative per person NH3 emissions. From 1981 to 2006, the total per person protein intake in the Canadian diet increased about 5%, but NH3 emission related to that diet decreased 20%. This is largely related to consumption of less beef, which has a high emission per unit of meat or protein, and more poultry and cereals which have much lower emissions. Although these changes in diet were not because of environmental concerns by the consumers, they had substantial effects on national-level emissions. These consumer driven effects may well exceed the possible effects of best management practices intended to address NH3 emissions at the producer level. Note that the Canadian population has increased 50% from 1981 to 2006 and meat and egg exports increased 570%, so that total emissions from food production in Canada have increased. Our results imply there will be further effects on national NH3 emissions because of dietary and export drivers that are generally outside the scope of agro-environmental policy. © 2014 Elsevier Ltd.

Sheppard S.C.,ECOMatters Inc. | Sanipelli B.,ECOMatters Inc.
Journal of Environmental Quality | Year: 2012

Modern animal feeds oft en include nutritional mineral supplements, especially elements such as Cu, P, Se, and Zn. Other sources of trace elements also occur in livestock systems, such as pharmaceutical use of As and Zn to control gut flora, Bi in dairy for mastitis control, and Cu as hoof dips. Additionally, potential exists for inadvertent inclusion of trace elements in feeds or manures. There is concern about long-term accumulation of trace elements in manured soil that may even exceed guideline "safe" concentrations. Th is project measured ~60 elements in 124 manure samples from broiler, layer, turkey, swine grower, swine nursery, sow, dairy, and beef operations. The corresponding feeds were also analyzed. In general, concentrations in manure were two- to fivefold higher than those in feed: the manure/feed concentration ratios were relatively consistent for all the animal-essential elements and were numerically similar for many of the non-nutrient elements. To confirm the potential for accumulation in soil, total trace element concentrations were measured in the profiles of 10 manured and 10 adjacent unmanured soils. Concentrations of several elements were found to be elevated in the manured soils, with Zn (and P) the most common. One soil from a dairy standing yard had concentrations of B that exceeded soil health guideline concentrations. Given that the Cu/P and Zn/P ratios found in manure were greater than typically reported in harvested crop materials, these elements will accumulate in soil even if manure application rates are managed to prevent accumulation of P in soil. © American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America.

Sheppard S.C.,ECOMatters Inc. | Herod M.,University of Ottawa
Journal of Environmental Radioactivity | Year: 2012

Assessment of the potential environmental impacts of nuclear fuel waste involves multiple lines of argument, one of which is an evaluation of the possible increments to background concentrations of certain radionuclides. This is especially relevant for radionuclides such as 3H, 36Cl and 129I where there is continuous cosmogenic or geogenic production. However, for 36Cl and 129I and certain U/Th-series radionuclides, data are scarce because the analysis methods are complex and costly. The present study used accelerator mass spectroscopy (AMS) to measure 36Cl and 129I in river waters throughout Canada. Radiochemical methods were used for 3H and the selected U/Th-series radionuclides, and stable element concentrations were also determined. There were distinct differences in concentrations among the sites. Stable Cl and I tended to be at higher concentrations near the ocean or population centres. The 3H was high in regions with power reactors. The 226Ra, 235U and 238U concentrations were high in areas with known U mineralizations, as expected. The 36Cl and 129I concentrations were generally homogenous in mid-latitudes, but the 129I concentration was lower in the one arctic site sampled. Because the stable and radioactive isotopes of Cl and I varied in response to different factors, the resulting specific activities were especially variable. Both Cl and I are homeostatically controlled in animals, thus it follows that dose from 36Cl and 129I will depend more closely on specific activity than concentration, and therefore the environmental increments of interest are in the specific activities rather than simply concentrations. © 2011 Elsevier Ltd.

Sheppard S.C.,ECOMatters Inc. | Bittman S.,Agriculture and Agri Food Canada
Agriculture, Ecosystems and Environment | Year: 2013

Manure nitrogen (N) includes what can be generalized as organic N, which includes undigested N from the feeds; ammoniacal and easily hydrolysable N, which includes urea and uric acid; and nitrate/nitrite species, which are the least abundant. From excretion to landspreading, the largest change in N concentration occurs because of volatilization of ammonia (NH3) from the ammoniacal and easily hydrolysable fraction. This process can be highly dependent on manure management, and some management strategies such as manure injection are largely designed to decrease NH3 loss. This paper utilizes recent models of NH3 emission from beef, dairy, swine and poultry production to estimate the net organic and ammoniacal N content of manure in Canadian Ecoregions before and after land spreading. Confinement versus grazing for beef is a major factor for overall net manure N application, and slurry versus solid manure is next most important. There are distinct differences among Ecoregions in the proportions of organic and ammoniacal N, so that generic assumptions are not appropriate. The estimates are mapped for all of Canada based on 2006 animal census. Several best management practices (BMPs) are evaluated using recent costing information (dollars per kg of NH3-N saved from emission). Relatively low-cost BMPs related to slurry manure applied nation-wide could save 16GgNH3-Nyear-1 for an estimated cost of $13M. Other low-cost BMPs could increase this to a saving of 79GgNH3-Nyear-1 or 26% of present emissions. © 2013 Elsevier B.V.

Sheppard S.C.,ECOMatters Inc. | Bittman S.,Agriculture and Agri Food Canada
Animal Feed Science and Technology | Year: 2011

National inventories of N emissions to the atmosphere from cattle depend on reliable information about husbandry practices, with appropriate spatial and temporal resolution. A survey of ∼1400 beef cattle farmers was used to quantify the prevalence of pasture and forage management practices that impact N intake and NH3 emissions, with implications for N2O emissions. These survey data were coupled to a mass balance model to inventory NH3 emissions by accounting for total ammoniacal (i.e., ammonia and ammonium) N (TAN) from excretion through to land spreading. As inputs, the model required excretion fractions, 2006 Canadian Census of Agriculture animal populations and detailed farm management practices from the survey. The N intake by grazing cattle was especially difficult to quantify. Early season grazing, when forages have elevated crude protein (>300gCP/kgdry matter), indicated potential for elevated emissions in May and June. Such exceptional CP concentrations during spring grazing may be important for N emissions, especially NH3. Additionally, beef cattle were reported by producers to spend 7-30%) of their time congregated, such as around water sources, feed or shade trees. This level of piosphere activity was attributed in the model to ∼20% increases in NH3 emissions relative to open pasture, and similar or higher effects would be expected for N2O emissions.This paper is part of the special issue entitled: Greenhouse Gases in Animal Agriculture-Finding a Balance between Food and Emissions, Guest Edited by T.A. McAllister, Section Guest Editors: K.A. Beauchemin, X. Hao, S. McGinn and Editor for Animal Feed Science and Technology, P.H. Robinson. © 2011 Elsevier B.V.

Sheppard S.C.,ECOMatters Inc. | Bittman S.,Agriculture and Agri Food Canada
Canadian Journal of Animal Science | Year: 2012

Beef cattle farms in Canada are very diverse, both in size and management. Because the total biomass of beef cattle in Canada is larger than any other livestock sector, beef also has the potential for the largest environmental impact. In this study we estimate NH3 emissions associated with beef cattle production across Canada using data on farm practices obtained from a detailed survey answered by 1380 beef farmers in 11 Ecoregions. The farms were various combinations of cow/calf, backgrounding and finishing operations. The proportion of animals on pasture varied markedly among Ecoregions, especially for cows and calves, and this markedly affected the estimated NH3 emissions. The crop components of feed also varied among Ecoregions, but the resulting crude protein concentrations were quite consistent for both backgrounding and finishing cattle. Manure was stored longer in the west than in the east, and fall spreading of manure was notably more common in the west, especially when spread on tilled land. The estimated NH3 emissions per animal were relatively consistent across Ecoregions for confinement production, but because the proportion of animals on pasture varied with Ecoregion, so did the overall estimated NH3 emissions per animal. Temperature is a key factor causing Ecoregion differences, although husbandry and manure management practices are also important. Hypothetical best management practices had little ability to reduce overall emission estimates, and could not be implemented without detailed cost/benefit analysis.

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