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T. M. Desutter - One of the best experts on this subject based on the ideXlab platform.

  • toward site specific design standards for animal Waste Lagoons protecting ground water quality
    Journal of Environmental Quality, 2000
    Co-Authors: J. M. Ham, T. M. Desutter
    Abstract:

    Seepage losses from animal-Waste Lagoons can affect ground water quality, if facilities are not properly sited, designed, and constructed. Most states in the Great Plains stipulate that earthen Lagoons cannot seep more than some specified rate (mm d -1 ). These criteria often apply to the entire state and all livestock species, although ground water vulnerability and Waste characteristics are highly variable from site to site. Because of this variability, statewide blanket regulations may overregulate some producers and underregulate others. Furthermore, wide disparity exists in seepage allowances among neighboring states, and regulations often are influenced by public opinion rather than scientific findings. This paper argues that lagoon design should be site specific and presents a logical framework to determine the maximum allowable seepage rate for a given location and type of operation (e.g., dairy, swine, cattle feedlot). Site-specific factors, such as soil properties, depth to water table, and chemistry of the Waste, are used to arrive at lagoon performance standards that minimize long-term risk. The decision process within the framework is presented as a conceptual model for lagoon permitting and may need to be customized to meet the requirements of each state. Nevertheless, use of site-specific design criteria will ensure that manure storages are adequate (e.g., plastic-lined Lagoons) in regions with vulnerable ground water, while providing reduced lagoon construction costs (lower cost of soil-lined Lagoons) for producers who site their operations in areas of low risk. To complement the site-specific approach, the whole-lagoon seepage rate should be measured after construction to verify that the prescribed performance criteria have been met.

  • Toward Site‐Specific Design Standards for Animal‐Waste Lagoons: Protecting Ground Water Quality
    Journal of Environmental Quality, 2000
    Co-Authors: J. M. Ham, T. M. Desutter
    Abstract:

    Seepage losses from animal-Waste Lagoons can affect ground water quality, if facilities are not properly sited, designed, and constructed. Most states in the Great Plains stipulate that earthen Lagoons cannot seep more than some specified rate (mm d -1 ). These criteria often apply to the entire state and all livestock species, although ground water vulnerability and Waste characteristics are highly variable from site to site. Because of this variability, statewide blanket regulations may overregulate some producers and underregulate others. Furthermore, wide disparity exists in seepage allowances among neighboring states, and regulations often are influenced by public opinion rather than scientific findings. This paper argues that lagoon design should be site specific and presents a logical framework to determine the maximum allowable seepage rate for a given location and type of operation (e.g., dairy, swine, cattle feedlot). Site-specific factors, such as soil properties, depth to water table, and chemistry of the Waste, are used to arrive at lagoon performance standards that minimize long-term risk. The decision process within the framework is presented as a conceptual model for lagoon permitting and may need to be customized to meet the requirements of each state. Nevertheless, use of site-specific design criteria will ensure that manure storages are adequate (e.g., plastic-lined Lagoons) in regions with vulnerable ground water, while providing reduced lagoon construction costs (lower cost of soil-lined Lagoons) for producers who site their operations in areas of low risk. To complement the site-specific approach, the whole-lagoon seepage rate should be measured after construction to verify that the prescribed performance criteria have been met.

Jay M. Ham - One of the best experts on this subject based on the ideXlab platform.

  • Measuring Seepage from Waste Lagoons and Earthen Basins with an Overnight Water Balance Test
    Transactions of the ASABE, 2009
    Co-Authors: Jay M. Ham, K. A. Baum
    Abstract:

    Previous work demonstrated that whole-lagoon seepage rates could be determined by measuring the difference between the change in depth and cumulative evaporation over a 5-day period when Waste inputs are withheld. However, faster techniques are needed to make the approach more cost effective and more logistically feasible at sites that can halt Waste inputs for only 1 to 2 days. Research was conducted to develop a simplified overnight water balance test. Data were collected at several earthen-lined Waste storages in Kansas. Evaporation was measured by eddy covariance and compared with that estimated by the bulk transfer equation; infrared measurements of Waste surface temperature and weather data collected on the lagoon berm were used as inputs. Pressure probes and a float recorder were installed near the shoreline to measure depth changes. Data from berm-deployed weather stations were adequate for predicting evaporation with the bulk transfer equation, provided wind speed was downscaled by 27% to represent conditions near the Waste surface. Depth sensors positioned on the upwind and downwind sides of the basin agreed when winds speeds were less than about 3 m s-1. Nighttime (2130 to 0630 h) evaporation ranged from 0.2 to 2.2 mm in May and June. Good agreement in the seepage estimates (e.g., 4.2 ±0.6 mm d-1) was found among tests conducted on consecutive nights at the same lagoon. Confidence in the seepage estimate was increased by repeating the overnight test for two consecutive or near-consecutive nights.

  • Movement of lagoon-liquor constituents below four animal-Waste Lagoons.
    Journal of environmental quality, 2005
    Co-Authors: Thomas M. Desutter, Gary M. Pierzynski, Jay M. Ham
    Abstract:

    Movement of liquor constituents from animal-Waste Lagoons has the potential to degrade ground water quality. The depth of movement and concentrations of lagoon-liquor constituents in the soil underlying three cattle (Bos taurus)-Waste retention Lagoons and one swine (Sus scrofa)-Waste lagoon were determined. Samples were taken by using a direct-push coring machine, dissected by depth, and analyzed for total N, organic C, CaCO3, pH, cation exchange capacity (CEC), texture, and extractable NO3, NH(4), P, Cl, Ca, Mg, K, and Na. Ammonium N concentrations were greatest in the upper 0.5 m of soil under all four Lagoons with concentrations ranging from 94 to 1139 mg kg(-1). Organic N was determined to make up between 39 and 74% of the total N beneath all Lagoons. The swine lagoon had 2.4 kg N m(-2) in the underlying soil whereas the cattle lagoon with highest quantity of N had 1.2 kg N m(-2) in the underlying soil. Although N concentrations decreased with depth, N was greater than expected background levels at the bottom of some cores, indicating that the sampling efforts did not reach the bottom of the N plume. Nitrate N concentrations were generally less than 5 mg kg(-1) immediately below the lagoon floor. In the uppermost 0.5 m of soil underlying the swine and three cattle Lagoons, NH4+ occupied 44% and between 1 and 22% of the soil cation exchange sites, respectively. The depth of movement of N under these Lagoons, as much as 4 m, may pose remediation difficulties at lagoon closure.

  • Evaluating Seepage Losses and Liner Performance at Animal Waste Lagoons using Water Balance Methods
    2004
    Co-Authors: Jay M. Ham
    Abstract:

    This chapter discusses techniques for evaluating seepage losses from existing animal Waste Lagoons under field conditions.

  • Uncertainty analysis of the water balance technique for measuring seepage from animal Waste Lagoons.
    Journal of environmental quality, 2002
    Co-Authors: Jay M. Ham
    Abstract:

    Water balance measurements can be used to estimate seepage rates from animal Waste Lagoons and earthen storages. This method requires detailed measurements of depth changes and cumulative evaporation during 5- to 10-d periods. Quantifying the uncertainty surrounding the measurements is crucial if data from seepage tests are used to determine if Lagoons are meeting engineering specifications and operating within regulatory guidelines. Uncertainty analyses, using a 95% confidence interval, were applied to field data collected during studies of animal Waste Lagoons in Kansas and Oklahoma. Changes in depth were measured with float-based recorders and evaporation was estimated from meteorological observations. Results showed that rate changes in depth could be measured to within +/-0.28 mm d(-1) or better when wind speeds at the start and end of the test were less than 4 m s(-1). Uncertainty in evaporation was the most significant factor affecting the seepage estimate, and surface temperature and relative humidity were the main sources of imprecision in the evaporation calculations. Evaporation could be estimated to within 10 to 20%, with the largest uncertainty occurring during windy conditions. Uncertainty in the calculated seepage rate increased as evaporation increased. When evaporation rates are low (e.g.,

  • uncertainty analysis of the water balance technique for measuring seepage from animal Waste Lagoons
    Journal of Environmental Quality, 2002
    Co-Authors: Jay M. Ham
    Abstract:

    Water balance measurements can be used to estimate seepage rates from animal Waste Lagoons and earthen storages. This method requires detailed measurements of depth changes and cumulative evaporation during 5- to 10-d periods. Quantifying the uncertainty surrounding the measurements is crucial if data from seepage tests are used to determine if Lagoons are meeting engineering specifications and operating within regulatory guidelines. Uncertainty analyses, using a 95% confidence interval, were applied to field data collected during studies of animal Waste Lagoons in Kansas and Oklahoma. Changes in depth were measured with float-based recorders and evaporation was estimated from meteorological observations. Results showed that rate changes in depth could be measured to within +/-0.28 mm d(-1) or better when wind speeds at the start and end of the test were less than 4 m s(-1). Uncertainty in evaporation was the most significant factor affecting the seepage estimate, and surface temperature and relative humidity were the main sources of imprecision in the evaporation calculations. Evaporation could be estimated to within 10 to 20%, with the largest uncertainty occurring during windy conditions. Uncertainty in the calculated seepage rate increased as evaporation increased. When evaporation rates are low (e.g., <4 mm d(-1)), seepage can be estimated to within +/-0.5 mm d(-1) with 95% confidence. A precision of +/-0.25 mm d(-1) is possible when research-grade instruments are deployed under favorable weather conditions. A measurement duration of 5 d is adequate for most water balance tests. In many cases, precision of the water balance technique will be sufficient in determining if a working lagoon is within regulatory guidelines.

Ofer Dahan - One of the best experts on this subject based on the ideXlab platform.

  • assessing the impact of dairy Waste Lagoons on groundwater quality using a spatial analysis of vadose zone and groundwater information in a coastal phreatic aquifer
    Journal of Environmental Management, 2014
    Co-Authors: S Baram, Daniel Kurtzman, Zeev Ronen, Aviva Peeters, Ofer Dahan
    Abstract:

    Dairy Waste Lagoons are considered to be point sources of groundwater contamination by chloride (Cl(-)), different nitrogen-species and pathogens/microorganisms. The objective of this work is to introduce a methodology to assess the past and future impacts of such Lagoons on regional groundwater quality. The method is based on a spatial statistical analysis of Cl(-) and total nitrogen (TN) concentration distributions in the saturated and the vadose (unsaturated) zones. The method provides quantitative data on the relation between the locations of dairy Lagoons and the spatial variability in Cl(-) and TN concentrations in groundwater. The method was applied to the Beer-Tuvia region, Israel, where intensive dairy farming has been practiced for over 50 years above the local phreatic aquifer. Mass balance calculations accounted for the various groundwater recharge and abstraction sources and sinks in the entire region. The mass balances showed that despite the small surface area covered by the dairy Lagoons in this region (0.8%), leachates from Lagoons have contributed 6.0% and 12.6% of the total mass of Cl(-) and TN (mainly as NO3(-)-N) added to the aquifer. The chemical composition of the aquifer and vadose zone water suggested that irrigated agricultural activity in the region is the main contributor of Cl(-) and TN to the groundwater. A low spatial correlation between the Cl(-) and NO3(-)-N concentrations in the groundwater and the on-land location of the dairy farms strengthened this assumption, despite the dairy Waste lagoon being a point source for groundwater contamination by Cl(-) and NO3(-)-N. Mass balance calculations, for the vadose zone of the entire region, indicated that drying of the Lagoons would decrease the regional groundwater salinization process (11% of the total Cl(-) load is stored under Lagoons). A more considerable reduction in the groundwater contamination by NO3(-)-N is expected (25% of the NO3(-)-N load is stored under Lagoons). Results demonstrate that analyzing vadose zone and groundwater data by spatial statistical analysis methods can significantly contribute to the understanding of the relations between groundwater contaminating sources, and to assessing appropriate remediation steps.

  • Infiltration Mechanism Controls Nitrification and Denitrification Processes under Dairy Waste Lagoon
    Journal of environmental quality, 2012
    Co-Authors: S Baram, Daniel Kurtzman, Zeev Ronen, Shai Arnon, Ofer Dahan
    Abstract:

    Earthen Waste Lagoons are commonly used to store liquid Wastes from concentrated animal feeding operations. The fate of ammonium (NH) and nitrate (NO) was studied in the vadose zone below earthen-clay dairy farm Waste Lagoons using three independent vadose zone monitoring systems. The vadose zone was monitored from 0.5 to 30 m below land surface through direct sampling of the sediment porewater and continuous measurement of the sediment profile's water content variations. Four years of monitoring revealed that Wastewater infiltration from the lagoon is controlled by two mechanisms: slow (mm d), constant infiltration from the lagoon bed; and rapid (m h) infiltration of Wastewater and rainwater via preferential flow in desiccation cracks formed in the unsaturated clay sediment surrounding the lagoon banks. The preferential flow mechanism is active mainly during Wastewater-level fluctuations and intensive rain events. The vadose zone below the Waste sources remained unsaturated throughout the monitoring period, and all infiltrating NH was oxidized in the upper 0.5 m. The NH oxidation (nitrification) was coupled with NO reduction (denitrification) and depended on the sediment water content, which was controlled by the infiltration mechanism. Coupled nitrification-denitrification (CND) resulted in 90 to 100% reduction in the total nitrogen mass in the vadose zone, with higher removal under high water content (∼0.55 m m). Mass balance of nitrogen and isotopic composition of NO indicated that CND, rather than cation exchange capacity, is the key factor regulating nitrogen's fate in the vadose zone underlying earthen Waste Lagoons.

  • Water percolation through a clayey vadose zone
    Journal of Hydrology, 2012
    Co-Authors: S Baram, Daniel Kurtzman, Ofer Dahan
    Abstract:

    Summary Heavy clay soils are regarded as less permeable due to their low saturated hydraulic conductivities, and are perceived as safe for the construction of unlined or soil-lined Waste Lagoons. Water percolation dynamics through a smectite-dominated clayey vadose zone underlying a dairy Waste lagoon, Waste channel and their margins was investigated using three independent vadose-zone monitoring systems. The monitoring systems, hosting 22 TDR sensors, were used for continuous measurements of the temporal variation in vadose zone water-content profiles. Results from 4 years of continuous measurements showed quick rises in sediment water content following rain events and temporal Wastewater overflows. The percolation pattern indicated dominance of preferential flow through a desiccation-crack network crossing the entire clay sediment layer (depth of 12 m). High water-propagation velocities (0.4–23.6 m h −1 ) were observed, indicating that the desiccation-crack network remains open and serves as a preferential flow pathway year-round, even at high sediment water content (∼0.50 m 3  m −3 ). The natural formation of desiccation-crack networks at the margins of Waste Lagoons induces rapid infiltration of raw Waste to deep sections of the vadose zone, bypassing the sediment’s most biogeochemically active parts, and jeopardizing groundwater quality.

  • Transport of testosterone and estrogen from dairy-farm Waste Lagoons to groundwater.
    Environmental science & technology, 2008
    Co-Authors: Shai Arnon, S Baram, Zeev Ronen, Ofer Dahan, Sara Elhanany, Keren Cohen, Irena Pankratov, Amit Gross, Laurence S. Shore
    Abstract:

    Although concentrated animal feeding operations constantly generate physiologically active steroidal hormones, little is known of their environmental fate. Estrogen and testosterone concentrations in groundwater and their distribution in sediments below a dairy-farm Wastewater lagoon were therefore determined and compared to a reference site located upgradient of the farm. Forward simulations of flow as well as estrogen and testosterone transport were conducted based on data from the sediment profile obtained during drilling of a monitoring well below the dairy-farm Waste lagoon. Testosterone and estrogen were detected in sediments to depths of 45 and 32 m, respectively. Groundwater samples were directly impacted by the dairy farm, as evidenced by elevated concentrations of nitrate, chloride, testosterone, and estrogen as compared to the reference site. Modeling potential transport of hormones in the vadose zone via advection, dispersion, and sorption could not explain the depths at which estrogen and tes...

J. M. Ham - One of the best experts on this subject based on the ideXlab platform.

  • Seepage losses from animal Waste Lagoons: A summary of a four-year investigation in Kansas
    Transactions of the ASAE, 2002
    Co-Authors: J. M. Ham
    Abstract:

    Seepage losses from animal Waste Lagoons can affect groundwater quality if liquid effluent is not properly contained within the basin. Seepage rates from 20 anaerobic Lagoons were measured using water balance methods. Study locations included 14 swine sites, 5 cattle feedlots, and a single dairy. Seepage results and basin geometry were used to estimate the hydraulic conductivity (Ks) of the compacted soil liner at each site. Seepage data and Waste chemistry were used to calculate rates of chemical export into the vadose zone. Profiles of ammonium–nitrogen (N) and other chemicals were determined by sampling soils beneath old Lagoons. Seepage rates from 20 Lagoons averaged 1.1 mm/d and ranged from 0.2 to 2.4 mm/d. Fifteen of the 20 Lagoons had seepage rates between 0.5 and 1.5 mm/d. The variation among locations was small despite large differences in soil types and depths to groundwater. On average, the Ks of lagoon liners was 1.8 U 10–7 cm/s. Variation in seepage rates and Ks among sites was lognormally distributed. There was evidence that seepage was moderated by the organic sludge that blankets the bottom of Lagoons. Concentrations of nitrogen, phosphorus, and other Waste constituents were, on average, 3 to 5 times higher in swine Waste Lagoons compared to cattle feedlot Lagoons. Ammonium–N seepage into the subsoil ranged from 2000 to 5000 kg ha–1 yr–1 at the larger swine sites but averaged 385 kg ha–1 yr–1 at cattle feedlots. Soil cores showed that concentrations of ammonium–N, organic–N, phosphorus, and other cations were highest near the original floor of the lagoon but decreased markedly with depth. In most cases, concentrations of nutrients in the soil returned to background levels about 3 m under the Lagoons. Additional research is needed on fate and transport of contaminants that accumulate beneath Lagoons and best management practices for lagoon closure.

  • toward site specific design standards for animal Waste Lagoons protecting ground water quality
    Journal of Environmental Quality, 2000
    Co-Authors: J. M. Ham, T. M. Desutter
    Abstract:

    Seepage losses from animal-Waste Lagoons can affect ground water quality, if facilities are not properly sited, designed, and constructed. Most states in the Great Plains stipulate that earthen Lagoons cannot seep more than some specified rate (mm d -1 ). These criteria often apply to the entire state and all livestock species, although ground water vulnerability and Waste characteristics are highly variable from site to site. Because of this variability, statewide blanket regulations may overregulate some producers and underregulate others. Furthermore, wide disparity exists in seepage allowances among neighboring states, and regulations often are influenced by public opinion rather than scientific findings. This paper argues that lagoon design should be site specific and presents a logical framework to determine the maximum allowable seepage rate for a given location and type of operation (e.g., dairy, swine, cattle feedlot). Site-specific factors, such as soil properties, depth to water table, and chemistry of the Waste, are used to arrive at lagoon performance standards that minimize long-term risk. The decision process within the framework is presented as a conceptual model for lagoon permitting and may need to be customized to meet the requirements of each state. Nevertheless, use of site-specific design criteria will ensure that manure storages are adequate (e.g., plastic-lined Lagoons) in regions with vulnerable ground water, while providing reduced lagoon construction costs (lower cost of soil-lined Lagoons) for producers who site their operations in areas of low risk. To complement the site-specific approach, the whole-lagoon seepage rate should be measured after construction to verify that the prescribed performance criteria have been met.

  • Toward Site‐Specific Design Standards for Animal‐Waste Lagoons: Protecting Ground Water Quality
    Journal of Environmental Quality, 2000
    Co-Authors: J. M. Ham, T. M. Desutter
    Abstract:

    Seepage losses from animal-Waste Lagoons can affect ground water quality, if facilities are not properly sited, designed, and constructed. Most states in the Great Plains stipulate that earthen Lagoons cannot seep more than some specified rate (mm d -1 ). These criteria often apply to the entire state and all livestock species, although ground water vulnerability and Waste characteristics are highly variable from site to site. Because of this variability, statewide blanket regulations may overregulate some producers and underregulate others. Furthermore, wide disparity exists in seepage allowances among neighboring states, and regulations often are influenced by public opinion rather than scientific findings. This paper argues that lagoon design should be site specific and presents a logical framework to determine the maximum allowable seepage rate for a given location and type of operation (e.g., dairy, swine, cattle feedlot). Site-specific factors, such as soil properties, depth to water table, and chemistry of the Waste, are used to arrive at lagoon performance standards that minimize long-term risk. The decision process within the framework is presented as a conceptual model for lagoon permitting and may need to be customized to meet the requirements of each state. Nevertheless, use of site-specific design criteria will ensure that manure storages are adequate (e.g., plastic-lined Lagoons) in regions with vulnerable ground water, while providing reduced lagoon construction costs (lower cost of soil-lined Lagoons) for producers who site their operations in areas of low risk. To complement the site-specific approach, the whole-lagoon seepage rate should be measured after construction to verify that the prescribed performance criteria have been met.

  • MEASURING EVAPORATION AND SEEPAGE LOSSES FROM Lagoons USED TO CONTAIN ANIMALWaste
    Transactions of the ASAE, 1999
    Co-Authors: J. M. Ham
    Abstract:

    Seepage (S) from animal-Waste Lagoons was estimated using a water balance approach by measuring changes in Waste level (i.e., depth) ( D) and evaporation (E) over brief periods (e.g., 6 days) when all other inflow and outflow were precluded. Data were collected at commercial swine and cattle feedlots in southwestern Kansas. Precision Waste level recorders, floating evaporation pans, and meteorological models were used to measure each lagooni¯s water balance. Different strategies for calculating evaporation and seepage were compared. Initial work at a 2.5-ha plastic-lined lagoon (S = 0, E 5.1 mm di©1) showed that evaporation over 6- to 11-day periods could be measured to within i¾0.5 mm di©1 with floating evaporation pans using a pan coefficient of 0.81. A bulk-transfer evaporation model, which incorporated realtime measurements of lagoon surface temperature, predicted evaporation to within 6% when using a transfer coefficient of 2.8 i? 10i©3. Evaporation models that did not include surface temperature resulted in significant errors (e.g., > 50%) under certain environmental conditions. The water balance of a soil-lined, cattle-feedlot lagoon over an 11-day period was: D = 2.1; E = 1.9, and S = 0.2, all in mm di©1. Additional work over a 6-day period at a soil-lined, swine-Waste lagoon resulted in a water balance of: D = 5.4; E = 4.5, and S = 0.9, all in mm di©1. Data suggest that seepage from Lagoons can be determined to within i¾0.5 mm di©1 by making precision water balance measurements over short periods (5 to 10 days), if evaporation is less than 6 mm di©1.

Roderick I. Mackie - One of the best experts on this subject based on the ideXlab platform.

  • Molecular Ecology Of Macrolide–Lincosamide–Streptogramin B Methylases in Waste Lagoons and Subsurface Waters Associated with Swine Production
    Microbial Ecology, 2010
    Co-Authors: Satoshi Koike, Rustam I. Aminov, A. C. Yannarell, Holly D. Gans, Ivan G. Krapac, Joanne C. Chee-sanford, Roderick I. Mackie
    Abstract:

    RNA methylase genes are common antibiotic resistance determinants for multiple drugs of the macrolide, lincosamide, and streptogramin B (MLS_B) families. We used molecular methods to investigate the diversity, distribution, and abundance of MLS_B methylases in Waste Lagoons and groundwater wells at two swine farms with a history of tylosin (a macrolide antibiotic structurally related to erythromycin) and tetracycline usage. Phylogenetic analysis guided primer design for quantification of MLS_B resistance genes found in tylosin-producing Streptomyces ( tlr (B), tlr (D)) and commensal/pathogenic bacteria ( erm (A), erm (B), erm (C), erm (F), erm (G), erm (Q)). The near absence of tlr genes at these sites suggested a lack of native antibiotic-producing organisms. The gene combination erm (ABCF) was found in all lagoon samples analyzed. These four genes were also detected with high frequency in wells previously found to be contaminated by lagoon leakage. A weak correlation was found between the distribution of erm genes and previously reported patterns of tetracycline resistance determinants, suggesting that dissemination of these genes into the environment is not necessarily linked. Considerations of gene origins in history (i.e., phylogeny) and gene distributions in the landscape provide a useful “molecular ecology” framework for studying environmental spread of antibiotic resistance.

  • molecular ecology of macrolide lincosamide streptogramin b methylases in Waste Lagoons and subsurface waters associated with swine production
    Microbial Ecology, 2010
    Co-Authors: Satoshi Koike, Rustam I. Aminov, A. C. Yannarell, Holly D. Gans, Ivan G. Krapac, Joanne C Cheesanford, Roderick I. Mackie
    Abstract:

    RNA methylase genes are common antibiotic resistance determinants for multiple drugs of the macrolide, lincosamide, and streptogramin B (MLSB) families. We used molecular methods to investigate the diversity, distribution, and abundance of MLSB methylases in Waste Lagoons and groundwater wells at two swine farms with a history of tylosin (a macrolide antibiotic structurally related to erythromycin) and tetracycline usage. Phylogenetic analysis guided primer design for quantification of MLSB resistance genes found in tylosin-producing Streptomyces (tlr(B), tlr(D)) and commensal/pathogenic bacteria (erm(A), erm(B), erm(C), erm(F), erm(G), erm(Q)). The near absence of tlr genes at these sites suggested a lack of native antibiotic-producing organisms. The gene combination erm(ABCF) was found in all lagoon samples analyzed. These four genes were also detected with high frequency in wells previously found to be contaminated by lagoon leakage. A weak correlation was found between the distribution of erm genes and previously reported patterns of tetracycline resistance determinants, suggesting that dissemination of these genes into the environment is not necessarily linked. Considerations of gene origins in history (i.e., phylogeny) and gene distributions in the landscape provide a useful “molecular ecology” framework for studying environmental spread of antibiotic resistance.

  • development validation and application of pcr primers for detection of tetracycline efflux genes of gram negative bacteria
    Applied and Environmental Microbiology, 2002
    Co-Authors: Rustam I. Aminov, Joanne C Cheesanford, N Garrigues, B Teferedegne, I J Krapac, Bryan A White, Roderick I. Mackie
    Abstract:

    Phylogenetic analysis of tetracycline resistance genes, which confer resistance due to the efflux of tetracycline from the cell catalyzed by drug:H+ antiport and share a common structure with 12 transmembrane segments (12-TMS), suggested the monophyletic origin of these genes. With a high degree of confidence, this tet subcluster unifies 11 genes encoding tet efflux pumps and includes tet(A), tet(B), tet(C), tet(D), tet(E), tet(G), tet(H), tet(J), tet(Y), tet(Z), and tet(30). Phylogeny-aided alignments were used to design a set of PCR primers for detection, retrieval, and sequence analysis of the corresponding gene fragments from a variety of bacterial and environmental sources. After rigorous validation with the characterized control tet templates, this primer set was used to determine the genotype of the corresponding tetracycline resistance genes in total DNA of swine feed and feces and in the Lagoons and groundwater underlying two large swine production facilities known to be impacted by Waste seepage. The compounded tet fingerprint of animal feed was found to be tetCDEHZ, while the corresponding fingerprint of total intestinal microbiota was tetBCGHYZ. Interestingly, the tet fingerprints in geographically distant Waste Lagoons were identical (tetBCEHYZ) and were similar to the fecal fingerprint at the third location mentioned above. Despite the sporadic detection of chlortetracycline in Waste Lagoons, no auxiliary diversity of tet genes in comparison with the fecal diversity could be detected, suggesting that the tet pool is generated mainly in the gut of tetracycline-fed animals, with a negligible contribution from selection imposed by tetracycline that is released into the environment. The tet efflux genes were found to be percolating into the underlying groundwater and could be detected as far as 250 m downstream from the Lagoons. With yet another family of tet genes, this study confirmed our earlier findings that the antibiotic resistance gene pool generated in animal production systems may be mobile and persistent in the environment with the potential to enter the food chain.

  • occurrence and diversity of tetracycline resistance genes in Lagoons and groundwater underlying two swine production facilities
    Applied and Environmental Microbiology, 2001
    Co-Authors: Joanne C Cheesanford, Rustam I. Aminov, I J Krapac, N Garriguesjeanjean, Roderick I. Mackie
    Abstract:

    In this study, we used PCR typing methods to assess the presence of tetracycline resistance determinants conferring ribosomal protection in Waste Lagoons and in groundwater underlying two swine farms. All eight classes of genes encoding this mechanism of resistance [tet(O), tet(Q), tet(W), tet(M), tetB(P), tet(S), tet(T), and otrA] were found in total DNA extracted from water of two Lagoons. These determinants were found to be seeping into the underlying groundwater and could be detected as far as 250 m downstream from the Lagoons. The identities and origin of these genes in groundwater were confirmed by PCR-denaturing gradient gel electrophoresis and sequence analyses. Tetracycline-resistant bacterial isolates from groundwater harbored the tet(M) gene, which was not predominant in the environmental samples and was identical to tet(M) from the Lagoons. The presence of this gene in some typical soil inhabitants suggests that the vector of antibiotic resistance gene dissemination is not limited to strains of gastrointestinal origin carrying the gene but can be mobilized into the indigenous soil microbiota. This study demonstrated that tet genes occur in the environment as a direct result of agriculture and suggested that groundwater may be a potential source of antibiotic resistance in the food chain.