Part 2: Odor-Cued Grab Sampling of Transient Environmental Odor Events; Mapping the 'Rolling Unmasking Effect' of Downwind Odor Dispersion

Downwind odor characteristics can be very different depending upon the size of the upwind point-source, interim topography, and wind conditions. At one extreme, the downwind odor plume from a relatively large, confined animal feeding operation (CAFO), located on a flat open plain and under stable, near-straight-line wind conditions can be rather broad, sustained and predictable relative to a fixed receptor site downwind. In contrast, the plume from a small point-source (e.g., a roof vent stack) located on irregular topography and under rapidly shifting wind conditions can be intermittent and fleeting. These transient odor events can be surprisingly intense and offensive, in spite of their fleeting occurrence and perception. This work reports on efforts to optimize an environmental odor sampling strategy, which is optimized for the challenges of (1) sampling of such transient odor 'spikes' and (2) the prioritization of odors/odorants from multiple, closely co-located point-sources, under such transient event conditions. Protocol refinement has emerged by way of 2 environmental odor assessment projects which have been undertaken on behalf of the Missouri Department of Natural Resources. The challenge of transient odor events has been mitigated utilizing rapid, odor cued whole-air grab capture sampling into metalized-FEP gas sampling bags, followed by immediate adsorption transfer onto SPME fibers or sorbent tubes for stabilization during the shipment and storage interval between collection and final analysis. Initial results demonstrated approximately 11 fold increases in target odorant yields for 900 mL sorbent tube transfers from 2-3 second 'burst' odor event bag-captures, as compared to equivalent direct collections at the same downwind receptor location but during perceived (stable) odor 'lull' periods. Results-to-date targeting refinement and field trials of this integrated environmental odor assessment strategy are presented. Preliminary application targeting general odor sampling and point-source differentiation utilizing tracer gases is also presented.

Reflections on Odor Management for Animal Feeding Operations

Most animal feeding operation owners recognize that they need to manage odors from their operations as part of their social relationship with their neighbors and local community. That was not always the case. Odors, whether pleasant or unpleasant, can evoke strong emotions and physiological responses. Odors from animal feeding operations are normally considered unpleasant and offensive if strong smelling and smelled often or for long periods of time. Animal feeding operation owners need to be aware of their odor emissions and the impacts the odors have on their neighbors and community. Good neighbor relations and effective communications can help identify odor problems and communicate what is being done to manage them. Odor management research and education includes odor basics, key processes including generation, emissions and dispersion, impacts, community and neighbor relations, and numerous mitigation practices. Animal feeding operation owners considering practices to reduce odor emissions or their impacts need to weigh the costs, expected effectiveness, and how the practice fits into the overall operation. Policymakers need science-based information to make informed decisions that balance the concerns and needs of neighbors and the community and the businesswomen and men that own and operate the animal feeding operations. This paper provides a broad overview of animal feeding operation odors and odor management.

Geochemistry of Flood Waters from the Tar River, North Carolina Associated with Hurricane Matthew

Hurricane Matthew caused flooding in Eastern North Carolina that was categorized as a one in 500-year frequency event. Matthew was the second such event in less than 20 years, following Hurricane Floyd in 1999. The frequency of intense storms is projected to increase for many coastal areas, including North Carolina, because of climate change. The goal of this study was to gain a better insight into the geochemistry of flood waters associated with major flood events. Water samples (n = 22) from the Tar River in Greenville, North Carolina were collected over a two-week period after Matthew moved across the state. Results show that total Kjeldahl nitrogen, dissolved organic carbon, phosphate, and Escherichia coli concentrations and exports were significantly (p < 0.05) higher when the river was above flood stage relative to below. Isotopic analyses of δ15N and δ18O in NO3 in flood waters suggest that wastewater, possibly from sanitary sewer and confined animal feeding operation overflows, was the major source of nitrate associated with flood waters. Regulatory efforts to reduce nutrient loading to coastal waters may be complicated by contributions associated with intense storm events, given that such storms are becoming more frequent.

Fate of tetracycline antibiotics in dairy manure-amended soils

The US dairy industry has changed significantly during the past 20 years. The number of dairies declined 63% from 1997 to 2012 owing to the rise in concentrated animal feeding operations and the concomitant decline of small dairy farms. Efficient and cost-effective dairies adhering to the concentrated animal feeding operation business design are praised for their high milk production. However, with a per capita daily manure production of 55 kg, storage and disposal of manure at these large operations pose significant management challenges and environmental risks. Application to surrounding agricultural fields is a common practice for disposing of manure, but the fate and consequences of antibiotics present in dairy waste are issues of great concern. Although antibiotics in the environment promote microbial resistance, their risks to humans and the environment are not completely known. Understanding and predicting the fate of antibiotics from dairy manure in soils is complicated by the variability and complex interactions of soil factors in addition to the diversity of chemicals of emerging concern, their amphoteric structures, and potential antagonistic and synergistic interactions among chemicals of emerging concern. This review explores behavior of the tetracycline (TC) class of antibiotics from dairy manure in the soil environment. TC fate in soils depends significantly on soil pH, ionic strength, and soil organic matter (SOM). Molecular charge and physicochemical properties of TCs at typical soil pHs encourage strong sorption to soils; however, this interaction is complicated by organic matter and metals, and may also encourage development of antibiotic resistance. Furthermore, TC degradation products exhibit distinct properties from their parent compounds that also must be considered. Increased knowledge of the behavior of TC antibiotics in soil is needed to enable mitigation of their potential risks.