This study evaluated the effect of biodiesel as a co-solvent with the wood preservative creosote to reduce the amount of hydrocarbon-based carrier utilized. Small blocks of wood were treated at a pilot scale using three different creosote concentrations. The diluent used was a blend of 80% soybean biodiesel and 20% petroleum diesel. The efficacy of creosote was tested against brown rot and white rot fungi. The results of the wood-block test and agar test suggested that there was no significant effect of biodiesel on the efficacy of creosote as a wood preservative. As creosote-treated wood is commonly used for railway ties, its potential impact on the surrounding environment was also assessed by studying the leaching behavior of creosote–biodiesel–diesel blend treated railway ties. Rainfall simulators were used to imitate an exposure of treated wood to a significant amount of rainfall. Wood core drilled from the exposed railway ties and leaching water samples were analyzed for the levels of polycyclic aromatic hydrocarbons (PAHs) and total petroleum hydrocarbons (TPHs). Overall, this study demonstrated that the diluent containing biodiesel had no negative effect on the performance of creosote as a wood preservative and towards the natural environment.

Properly managed biopiles can be used for slaughterhouse-residual degradation and bacterial pathogen inactivation, which otherwise represent a major health risk in the environment. Biopiles were used to dispose of slaughterhouse-residuals and determine the occurrence and persistence patterns of indicators of pathogenic bacteria. The indicator bacteria included the family Enterobacteriaceae, total coliforms, Escherichia coli, nalidixic acid-resistant E. coli, and Streptococcus fecalis. The slaughterhouse-residual biopiles remained static for 164 d in 2006 and 141 d in 2007. In biopile effluent samples, exponentially decreasing populations of the indicator bacteria were observed. Indicator bacteria presence in biopile and soil samples suggested their retention and persistence in, but not migration from, the media. Though the family Enterobacteriaceae, total coliforms, and Escherichia coli shared behavioral correlations, they exhibited different fates in all media compared to S. fecalis, which was observed to persist and re-grow. The behavior of inoculated nalidixic acid-resistant E. coli suggested that inactivation was the primary process in the biopiles. However, the biopiles constituted continual sources of the indicator bacteria due to their persistence in isolated and protected locations, and changes in dominant species. While biopiling slaughterhouse-residuals was effective to inactivate >99% (log reductions) of indicator bacteria, tertiary methods and biopiling phases should be employed to ensure inactivation of pathogenic bacteria in animal waste biopiles. The fate of bacterial indicators in this system exhibited trends not-as-yet observed for animal waste biopiling activities, which generates numerous questions for further research.

Biopiles can be used to dispose of slaughterhouse residuals (SLRs); however, the fate of pathogenic bacteria (e.g., pathogenic strains of , ) in these systems is not well understood. The transport of these bacteria in water leaching from the biopile could represent a significant contamination source. This research examined the transport of Enterobacteriaceae and Enterococcaceae indicator bacteria from SLR biopiles. Three biopiles (2.6 m wide by 4.6 m long by 1.8 m high) were formed on soil layers in concrete cells that allowed for real-time monitoring of environmental parameters, hydrologic flux, and indicator bacteria levels in effluent leaching from the piles. In biopile effluent, indicator bacteria populations decreased exponentially following biopile formation. Indicator bacteria loads in effluent constituted <0.01% of the initial indicator bacteria levels in the biopiles, which was attributed to retention, inactivation, and death. Nearly 90% of the total indicator bacteria loads coincided with large precipitation events (>15 mm d). Movement of the indicator bacteria through the biopiles and underlying soil appeared to be consistent with preferential flow phenomena. The populations of the Enterobacteriaceae indicators remained low in conditions of higher soil water content and lower biopile temperatures, whereas the Enterococcaceae indicator appeared to regrow in these conditions. This indicated that bacterial pathogen transport from a biopile could be a concern after the disappearance of conventional bacterial indicators, such as . Management considerations should attempt to divert excess water from entering a biopile, such as locating a biopile under a roof. Unsaturated biopile and soil conditions should be maintained to impede water flow through preferential pathways in the soil underneath a biopile.

A 2-yr study compared the performance of seasonally and continuously loaded constructed wetlands treating dairy farm wastewater. One wetland was loaded during the growing season (GS) periods only, while the other was continuously loaded. Weekly samples were analyzed for 5-d biochemical oxygen demand (BOD), total suspended solids (TSS), total Kjeldahl N (TKN), total ammoniacal N (TAN), total P (TP), and . Annual average daily mass removal rates (kg ha) were similar for both wetlands in both years; however, seasonal differences were observed. With the exception of BOD in Year 2, average daily GS areal mass removal rates were higher for the seasonal wetland. However, GS mass exports from the seasonal wetland were higher by 28 to 94%, with the exception of BOD in Year 1. Annual mass reductions (MRs; %) for nutrients were higher for the continuous wetland in both years. Annual MRs were similar for in both years and for TSS in Year 2. Annual mass exports from the seasonal wetland were higher for nutrients and by 14 to 77% in both years. Pollutant MRs generally decreased during the nongrowing season (NGS) for the continuous wetland; however, in Year 2 when lower loading rates were used, the wetland still removed 84 to 99% of the pollutant masses. The continuous wetland also performed better during periods of high flow that occurred during the GS. Although there were minimal differences in annual treatment performance, continuously loaded systems require less additional infrastructure and should require less maintenance and may, therefore, be more attractive for agricultural applications.

Roper, J. D., Burton, D. L., Madani, A. and Stratton, G. W. 2013. A simple method for quantifying dissolved nitrous oxide in tile drainage water. Can. J. Soil Sci. 93: 59-64. It is often assumed that the N2O produced from nitrification and denitrification in soil systems is lost primarily as a gas from the soil surface. However, the dissolution and eventual degassing of N2O in water leaching through, and draining from, agricultural fields is also a significant loss pathway. The quantification of this pathway of N2O loss has been limited by available methodologies for measuring dissolved gases in drainage water. Here a simple method is presented, which allows for the collection of tile drainage water samples using standard automated water sampling equipment that maintains the dissolved gases. Tile drainage water was collected in 1 L ISCO (TM) water sampling bottles outfitted with modified 10 mL volumetric pipettes. The pipettes provide a means of reducing the water:atmosphere interface for water held within the pipette thus reducing the N2O exchange with the atmosphere. The water samples are removed from the pipette using long slender needles attached to a 20-mL syringe, drawing 5 mL of water from within the bulb of the pipette. The dissolved N2O in the water samples was measured by headspace analysis using a gas chromatograph. A laboratory trial determined that retaining the water in the pipette bulbs resulted reduced N2O degassing such that N2O concentration did not decrease significantly in the first 24 h after filling of the bottle.

The effects of acid digestion procedures and instrumentation on extracted lead (Pb) concentrations from several soils, including a mildly Pb-contaminated soil, were determined using a two-factor factorial experiment. The two factors were (i) digestion procedure [seven levels: U. S. EPA, AOAC (dry ashing), nitric acid (NA), three aqua regia procedures (AR1, AR2, and AR3), and hydrofluoric acid (HF)] and (ii) instrumentation [two levels: atomic absorption spectrometry (AAS) and inductively coupled plasma (ICP) spectroscopy]. The greatest Pb recovery was obtained when soils were digested with HF and analyzed by AAS. The results suggest that the AOAC procedure (a standard procedure for recovery of soil nutrients and trace elements in Canadian laboratories) and EPA procedure (a standard procedure in American laboratories) may underestimate Pb concentrations in some Atlantic Canadian soil types. The AAS procedure is more accurate than ICP for determining Pb concentrations in soil with a history of PbHAsO4, at least for Atlantic Canadian soils.

Prominent bacterial pathogens, such as E. coli O157:H7 and Salmonellae sp. (SA), reside in multiple hosts, exist in animal,borne wastes, and are excreted by animals in large volumes. They have also been linked to increasing incidence of mammalian infections. Emerging zoonoses cause ≈12,24% of global infectious diseases, thus human and animal exposure to bacterial pathogens embodies a health risk. Livestock, for example, represent vectors for and defenses in bio, or agri,terrorism situations. It is impractical, however, to monitor for all bacterial pathogens due to difficulty, time, expense, virulence, and their ubiquity in nature. Indicator micro,organisms are therefore used to equate bacterial pathogen presence. Choosing a universal indicator is therefore a foremost concern that is continuously debated in academic and public circles. Escherichia coli (EC) and Streptococcus fecalis (SF) have historically been used as indicators of pathogens inherent in the gut of humans and warm,blooded animals. Since EC is the prominent species in the total (TC), fecal coliform (FC), and the Family Enterobacteriaceae (EB) groups, EC detection should coincide with detection of EB and TC. Likewise, TC or SA presence should elicit EB detection. Theoretically, since SF is not an EB member, no similarities in detection or ultimate fate should be observed. The crux of this research was to assess the fate of indicator bacteria fate in solid and liquid media associated with slaughterhouse,residual biopiles during the secondary composting phase. Traditional (membrane filtration; MF) and rapid (PetriFilm™) enumerative methods, and classical (TC, EC, SF) and non,classical (EB, SA, EC NAR) indicator bacteria, were used. This presentation will focus on the re,growth potential of these micro,organisms.

: Microbial contamination of surface waters is one of the most important water quality issues affecting the agricultural sector in Nova Scotia, Canada. Most farmers who irrigate in the province draw their source water directly from streams and rivers. One mode of pathogen transmission is the irrigation of horticultural crops with contaminated water. The extended storage of irrigation water prior to crop application could minimize this risk. Natural inactivation processes could, depending on the source water characteristics and length of storage time, reduce bacteria levels to acceptable use standards. The purpose of this project was to study bacterial population dynamics, specifically those of Escherichia coli, in shallow irrigation water reservoirs. Experiments, involving a series of dialysis tube survival studies, were conducted from May through September of 2006 in an operational farm reservoir to examine microbial inactivation kinetics. It was found that E. coli populations in the cool, lower layer (depth ≈ 3 m) did not decline, while populations in the warm upper layer (depth ≈ 1.0 m) experienced significant reductions over a period of several days. An inactivation model was calibrated and used to develop conservative estimates of T90, T99, and T99.9 values for environmental conditions typical of the Annapolis Valley of Nova Scotia. If a shallow reservoir was well mixed to prevent gradients in temperature and dissolved oxygen, storage of irrigation water for a period of at least two weeks would reduce bacterial numbers by at least three logs during the growing season in Nova Scotia.

A container experiment was conducted to test the hypothesis that uncomposted wool wastes could be used as nutrient source and growth medium constituent for container-grown plants. The treatments were: (1) rate of wool-waste application (0 or unamended control, 20, 40, 80, and 120g of wool per 8-in. pot), (2) growth medium constituents [(2.1) wool plus perlite, (2.2) wool plus peat, and (2.3) wool plus peat plus perlite], and (3) plant species (basil and Swiss chard). A single addition of 20, 40, 80, or 120g of wool-waste to Swiss chard (Beta vulgaris L.) and basil (Ocimum basilicum L.) in pots with growth medium provided four harvests of Swiss chard and five harvests of basil. Total basil yield from the five harvests was 1.6–5 times greater than the total yield from the unamended control, while total Swiss chard yield from the four harvests was 2–5 times greater relative to the respective unamended control. The addition of wool-waste to the growth medium increased Swiss chard and basil tissue N, and NO3–N and NH4–N in growth medium relative to the unamended control. Scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) microanalysis of wool fibers sampled at the end of the experiments indicated various levels of decomposition, with some fibers retaining their original surface structure. Furthermore, most of the wool fibers’ surfaces contained significant concentrations of S and much less N, P, or K. SEM/EDX revealed that some plant roots grow directly on wool-waste fibers suggesting either (1) root directional growth towards sites with greater nutrient concentration and/or (2) a possible role for roots or root exudates in wool decomposition. Results from this study suggest that uncomposted wool wastes can be used as soil amendment, growth medium constituent, and nutrient source for container-grown plants.

The environmental impact of three manure stockpiling systems - uncovered poultry litter, covered poultry litter and uncovered mink manure - on surface and subsurface water quality and air quality was evaluated during a 592 day in situ field storage experiment. Surface runoff and subsurface leachate was analyzed to determine TKN, NH3-N, NO3-N, and TP concentrations and mass loadings. Surface runoff was the main transportation mechanism of P loss from the stockpiles with the majority lost during the two fall seasons. N losses from the poultry litter stockpiles were greatest during the initial 250 days of storage with most of the N lost to subsurface leaching. In mink stockpiles, however, the majority of N was lost in surface runoff. E. coli counts in runoff and leachate samples were highest during the first several rainfall events, with low levels detectable after 200 days. Peak NH3, N2O and CH4 fluxes were observed during the initial stages of stockpiling with the majority of total emissions released during the first 17, 125 and 45 days, respectively.

The hypothesis of this work was that uncomposted sheep wool and human hair could be used as nutrient source for nonedible high-value plants. Pot and field experiments were conducted to assess uncomposted sheep wool-wastes and human hair-wastes as a nutrient source for high-value crops and to evaluate the effect of these waste materials on soil microbial community and mycorrhizae. In the pot experiments, addition of uncomposted wool- or hair-waste to soil increased yields from pot marigold (Calendula officinalis L.) and valerian (Valeriana officinalis L.). In the field experiment, wool-waste was added to purple foxglove (Digitalis purpurea L.) at rates of 0, 15.8, and 31.7 t ha(-1). Wool additions to soil increased foxglove yields over the next two seasons by 1.7 to 3.5 times relative to the control. Overall, addition of wool- or hair-waste to soil increased NH4-N and NO3-N in soil, increased total N (and protein) concentration in plant tissue, and stimulated soil microbial biomass. Scanning electron microscopy (SEM) and energy dispersive x-ray (EDX) analyses indicated that some of wool and hair in soil from the pot and field experiments, after two seasons and several harvests, retained their original structure, a significant concentration of S, some N, and were not fully decomposed. High rates of wool addition to soil in field experiments resulted in shifts in the microbial community composition, while a low rate of wool-waste addition did not affect the microbial community relative to the unamended control. Our results suggest that the addition of uncomposted wool-waste or hair-waste of only 0.33% by weight to soil would support at least 2 to 3 harvests of crops, without the addition of other fertilizers. Uncomposted wool and hair-wastes can be used as a nutrient source for high-value crops.

A paired stream approach was used to assess ecosystem health in two rural Nova Scotia streams (Thomas Brook and Sharpe Brook) with varying land-use practices. The objectives of the study were to assess stream health within an agricultural catchment, the Thomas Brook Watershed, and to identify parameters that could be used to characterize the impacts of agricultural land use on stream ecosystem health within intensively farmed watersheds in Nova Scotia. General water quality (nutrient concentrations, turbidity, pH, temperature) and the hydrology of both watersheds were monitored from May to October 2006. In addition, continuous dissolved oxygen (DO) and chlorophyll a data were collected in both streams, and benthic invertebrate populations were characterized during the study period. Diurnal DO data were analyzed to determine photosynthesis and respiration ratios. Macroinvertebrate data provided information on productivity, and on a number of other relevant metrics. Findings determined that agricultural land-use generally led to high nutrient concentrations, large dissolved oxygen variability, turbid waters, high chlorophyll a content, and impacted macroinvertebrate populations in streams. Forested land-use demonstrated typically unimpacted conditions. It was concluded that DO dynamics and macroinvertebrate metrics would be very useful for providing a generalized assessment of stream health in agricultural watersheds.

A movement towards more sustainable agriculture in Canada has resulted in the adoption of beneficial management practices, such as zero-tillage. The drive to implement zero- tillage is based on a desire to improve and protect soil and water quality, while contributing to the reduction of carbon dioxide concentrations in the atmosphere. However, net greenhouse gas impacts of converting to zero-tillage in eastern Canada are unclear, as there is a potential for increased nitrous oxide (N2O) emissions offsetting possible soil carbon storage. Discussion on the fate of nitrogen in soil assumes that N2O is lost to the atmosphere from the soil surface as a gas. However, the degassing of N2O dissolved in soil solution from agricultural drainage water is believed to contribute to N2O accumulation in the atmosphere. Here we examine the impact of tillage practices on soil hydrology, and its influence on the dissolution and transport of N2O in tile drainage water. Through measurements of N2O in tile drainage water it has been revealed that tillage practice does not have a significant impact on the amount of dissolved N2O released through tile drainage water.

It is often assumed that the nitrous oxide (N2O) produced from denitrification in soil systems is lost primarily as a gas from the soil surface. However, the degassing of N2O dissolved in soil solution from agricultural drainage water has been shown to be a significant loss pathway from agricultural systems. The quantification of this pathway of N2O loss is limited by available methodologies for measuring dissolved gases in drainage water samples. Here a simple method is presented as a means of sampling dissolved N2O found in agricultural drainage water. Tile water is collected in 1 L ISCO water sampling bottles, outfitted with modified 10 mL volumetric pipettes. To maintain the integrity of the sample, the potential for the sample to degas must be minimized. The pipettes allow this to be accomplished, as they significantly reduce the surface area of the water exposed to the atmosphere. The samples are collected using 20 gauge 30.5 cm penetration needles, drawing 5 mL of water from within the bulb of each of the pipettes. A 4 mL water sample is collected using a 20 mL syringe and injected into a 12 mL exetainer, which was evacuated and brought to atmospheric pressure. Prior to evacuation, 50 L of 6.25% (v/v) mercuric chloride (HgCl2) solution was added to the exetainer, inactivating bacterial function and thus, halting further gas evolution. The dissolved N2O in the tile drainage water is measured by the headspace analysis. A trial performed determined that the water could be left in the bottles exposed to the atmosphere for up to three days previous to seeing any significant decrease in N2O concentrations.

Constructed wetlands are cost effective wastewater treatment systems being increasingly used in agriculture. Efficient phosphorus (P) treatment by wetlands can however, be a challenge due to slow removal mechanisms. As a result, extended contact times are often required to achieve desired treatment. There are also concerns related to the long-term sustaina bility of P treatment. Therefore, a five year dataset from a surface flow constructed wetland located in Bible Hill Nova Scotia, Canada was examined to: 1) determine the effects of continued loading on P treatment and 2) evaluate hydrological impacts on P treatment. The wetland was intensively monitored year-round from November, 2000 through April, 2005 for total P (TP) and soluble reactive P(SRP). Dairy wastewater (milkhouse wash water and liquid manure) was loaded at 1.5 ± 1.0 kg ha−1 d−1 for TP and 1.0 ± 0.9 kg ha−1 d−1 for SRP. Mass reductions for the entire monitoring period were 53.7% and 52.7% for TP and SRP, respectively. Soils in this wetland appeared to have a sustained P adsorption capacity, with treatment being largely influenced by hydrology and fluctuations in wastewater loading rates. Linear regression of monthly TP and SRP mass reductions, with monthly outflow volumes resulted in decreased mass reductions with increased outflow. Monthly mass reductions were > 50% when corresponding outflows were < 100 mm. When monthly outflow exceeded 100 mm, however, mass reductions became highly variable. To maintain effective P management by constructed wetlands, the use of approaches that prevent high external hydrological loadings are recommended.

Tile drainage water from agricultural fields commonly exceeds environmental guidelines for phosphorus (P) in rivers and streams. The loss of P through artificial drainage is spatially and temporally variable, and is related to local factors. This study characterizes variability in total P (TP) and soluble reactive P (SRP) concentrations in weekly drainage samples from 39 agricultural fields in Nova Scotia, Canada, from April 2002 through December 2003. We examined connections between P concentrations and the factors: (i) soil texture; (ii) discharge flow rate; (iii) soil test P (STP); (iv) manure type; and (v) crop cover. Generally, variability between fields and samples was great, and fields with standard deviations exceeding the mean for TP, SRP, and flow rate were 71, 54, and 79%, respectively. It was evident that poultry and swine manure contributed to high STPs, and to constantly high TP concentrations with high proportions of SRP. Concentrations varied from week to week, and particularly in April, May, October, and November when the greatest TP, SRP, and flow rate averages were measured. Mean TP concentrations exceed the USEPA (1994) TP guideline of 0.10 mg L(-1) at 82% of the fields, and periodically concentrations more than 10 times, and occasionally more than 50 times higher than the guideline were found. The proportion of SRP in TP had a tendency to be higher when TP levels were high in coarse textured soils. In Nova Scotia, dairy manure is most often applied on permanent cover crops, which did not show as much P concentration variability as crop rotations. Daily or hourly observation of short-term increases in P concentrations related to the described factors would help to characterize the changes in P concentrations observed during frequent heavy drainage flow events.

Four years of performance data from a free-water surface constructed wetland receiving dairy wastewater in Nova Scotia was used to compute first order reaction rate constants (Ka) for several parameters including BOD5, TP, TKN, NH4+-N, FC, and TSS. Flow rates at the inlet and outlet of the 5 m wide × 20 m long wetland were continuously measured to assess how external hydrologic influences affected the water budget of the wetland and the system treatment performance. The Ka values were calculated using inlet and outlet concentrations and an assumption of plug flow hydraulics. Adjusted rate constants (Kac) were also computed, in which the effects of dilution and concentration on pollutant concentrations were considered. Precipitation, runoff, and evapotranspiration had a large influence on the wetland water budget. Values of Ka were higher than Kac for all wastewater parameters, illustrating the effects of dilution on outlet pollutant concentrations and the importance of accurately characterizing wetland hydrology when determining or using rate constants. The Kac values did not appear to be influenced by temperature or solar radiation, but were positively correlated with the hydraulic loading rate for most parameters. Rate constants were lower than those reported in the literature for livestock wastewater treatment wetlands operating in warmer climates. This could be due to differences in climate, but could also be attributed to the relatively high strength wastewater and low hydraulic loading rate (0.1 m month–1) used in this study. Key words: treatment wetlands, cold climate, agricultural wastewater, design, rate constants.