Surface and Subsurface Attenuation of Trenbolone Acetate Metabolites and Manure-Derived Constituents in Irrigation Runoff on Agro-Ecosystems

Although studies have evaluated the ecotoxicity and fate of trenbolone acetate (TBA) metabolites, namely 17α-trenbolone (17α-TBOH), 17β-trenbolone (17β-TBOH), and trendione (TBO), their environmental transport processes remain poorly characterized with little information available to guide agricultural runoff management. Therefore, we evaluated TBA metabolite transport in representative agricultural systems with concurrent assessment of other manure-derived constituents. Leachate generated using manure from TBA-implanted cattle was applied to a subsurface infiltration plot (4 m) and surface vegetative filter strips (VFSs; 3, 4, and 5 m). In the subsurface experiment, 17α-TBOH leachate concentrations were 36 ng L−1 but decreased to 12 ng L−1 in initial subsurface discharge. Over 75 minutes, concentrations linearly increased to 23 ng L−1 (C/Co = 0.32–0.64). In surface experiments (n = 4), 17α-TBOH leachate concentrations ranged from 11–150 ng L−1, remained nearly constant with time, but were attenuated by ∼70–90% after VFS treatment with no statistical dependence on the VFS length. While attenuation clearly occurred, the observations of a highly mobile fraction of all constituents in both surface runoff and subsurface discharge suggest that these treatment strategies may not always be capable of achieving threshold discharge concentrations. To attain no observed adverse effect levels (NOAELs) in receiving waters, concurrent assessment of leachate concentrations and available dilution capacities can be used to guide target treatment performance levels for runoff management. Dilution is usually necessary to achieve NOAELs, and receiving waters with less than 70–100 fold dilution capacity are at the highest risk for steroidal endocrine disruption

River Microbiome Composition Reflects Macroscale Climatic and Geomorphic Differences in Headwater Streams

Maintaining the quality and quantity of water resources in light of complex changes in climate, human land use, and ecosystem composition requires detailed understanding of ecohydrologic function within catchments, yet monitoring relevant upstream characteristics can be challenging. In this study, we investigate how variability in riverine microbial communities can be used to monitor the climate, geomorphology, land-cover, and human development of watersheds. We collected streamwater DNA fragments and used 16S rRNA sequencing to profile microbiomes from headwaters to outlets of the Willamette and Deschutes basins, two large watersheds prototypical of the U.S. Pacific Northwest region. In the temperate, north-south oriented Willamette basin, microbial community composition correlated most strongly with geomorphic characteristics (mean Mantel test statistic r = 0.19). Percentage of forest and shrublands (r = 0.34) and latitude (r = 0.41) were among the strongest correlates with microbial community composition. In the arid Deschutes basin, however, climatic characteristics were the most strongly correlated to microbial community composition (e.g., r = 0.11). In headwater sub-catchments of both watersheds, microbial community assemblages correlated with catchment-scale climate, geomorphology, and land-cover (r = 0.46, 0.38, and 0.28, respectively), but these relationships were weaker downstream. Development-related characteristics were not correlated with microbial community composition in either watershed or in small or large sub-catchments. Our results build on previous work relating streamwater microbiomes to hydrologic regime and demonstrate that microbial DNA in headwater streams additionally reflects the structural configuration of landscapes as well as other natural and anthropogenic processes upstream. Our results offer an encouraging indication that streamwater microbiomes not only carry information about microbial ecology, but also can be useful tools for monitoring multiple upstream watershed characteristics

Mammals of Padre Island National Seashore, Texas /

no.61 (2013

Trenbolone Acetate Metabolite Transport in Rangelands and Irrigated Pasture: Observations and Conceptual Approaches for Agro-Ecosystems

To assess the relative ecological risks of trenbolone acetate (TBA) use in agro-ecosystems, we evaluated the spatiotemporal dynamics of TBA metabolite transport during irrigation and rainfall events. Within a pasture, TBA-implanted heifers (40 mg TBA, 8 mg estradiol) were briefly penned (24 h) at high stocking densities (500 animal units (AU)/ha), prior to irrigation. Irrigation runoff concentrations of 17α-trenbolone (17α-TBOH) 0.3 m downslope were 11 ng/L in the wetting front, but quickly decreased to ?0.5 ng/L, suggesting mass transfer limitations to transport. At 3 and 30 m downslope, efficient attenuation of 17α-TBOH concentrations is best explained by infiltration and surface partitioning. At plot scales, transport through vegetated filter strips resulted in \u3c0.5?7 ng/L 17α-TBOH concentrations in rainfall-induced runoff with partial subsequent attenuation. Thus, even under intense grazing scenarios, TBA-metabolite transport potential is expected to be low in rangelands, with ecological risks primarily arising from uncontrolled animal access to receiving waters. However, 17α-TBOH concentrations in initial runoff were predicted to exceed threshold levels (i.e., no observed adverse effect levels [NOAELs]) for manure concentrations exceeding 2.0 ng/g-dw, which occurs throughout most of the implant life. For comparison, estrone and 17?-estradiol were modeled and are likely capable of exceeding NOAELs by a factor of ?2?5 in irrigation runoff, suggesting that both endogenous and exogenous steroids contribute to endocrine disruption potential in agro-ecosystems

Trenbolone Acetate Metabolite Transport in Rangelands and Irrigated Pasture: Observations and Conceptual Approaches for Agro-Ecosystems

To assess the relative ecological risks of trenbolone acetate (TBA) use in agro-ecosystems, we evaluated the spatiotemporal dynamics of TBA metabolite transport during irrigation and rainfall events. Within a pasture, TBA-implanted heifers (40 mg TBA, 8 mg estradiol) were briefly penned (24 h) at high stocking densities (500 animal units (AU)/ha), prior to irrigation. Irrigation runoff concentrations of 17α-trenbolone (17α-TBOH) 0.3 m downslope were 11 ng/L in the wetting front, but quickly decreased to ∼0.5 ng/L, suggesting mass transfer limitations to transport. At 3 and 30 m downslope, efficient attenuation of 17α-TBOH concentrations is best explained by infiltration and surface partitioning. At plot scales, transport through vegetated filter strips resulted in <0.5–7 ng/L 17α-TBOH concentrations in rainfall-induced runoff with partial subsequent attenuation. Thus, even under intense grazing scenarios, TBA-metabolite transport potential is expected to be low in rangelands, with ecological risks primarily arising from uncontrolled animal access to receiving waters. However, 17α-TBOH concentrations in initial runoff were predicted to exceed threshold levels (i.e., no observed adverse effect levels [NOAELs]) for manure concentrations exceeding 2.0 ng/g-dw, which occurs throughout most of the implant life. For comparison, estrone and 17β-estradiol were modeled and are likely capable of exceeding NOAELs by a factor of ∼2–5 in irrigation runoff, suggesting that both endogenous and exogenous steroids contribute to endocrine disruption potential in agro-ecosystems

Mass Balance Approaches to Characterizing the Leaching Potential of Trenbolone Acetate Metabolites in Agro-Ecosystems

Several studies have documented the occurrence and fate of trenbolone acetate (TBA) metabolites in soil and water. However, considerable uncertainty still exists with respect to TBA risk in agro-ecosystems because limited data are available to quantify excretion, transformation, and leaching processes. To address these uncertainties, we used experimental mesocosms and a mass balance approach to estimate the TBA metabolite leaching potential from manure excreted by implanted (40 mg TBA, 8 mg 17β-estradiol) beef cattle. Manure sample analysis indicates that over 113 days, a maximum of 9.3% (3,200 μg/animal unit [AU]) of the implant dose was excreted as 17α-trenbolone (17α-TBOH), and <1% was excreted as 17β-trenbolone (65 μg/AU) or trendione (3 μg/AU). While most (>97%) of the total excreted mass of 17α-TBOH transforms to uncharacterized products, 0.3–0.6% (100–220 μg/AU) of the implant dose accumulates on land surfaces and is available for subsequent transport. During rainfall or irrigation events, a maximum of 0.005–0.06% (1.6–22 μg/AU 17α-TBOH) or 0.005–0.012% (1.8–4 μg/AU 17α-TBOH) of the dose leached into runoff, respectively. Leaching potentials peak at 5–30 days postimplantation, suggesting that targeted timing of implantation and irrigation could minimize steroid leaching during rainfall and irrigation events

Selenium Cycling Across Soil-Plant-Atmosphere Interfaces: A Critical Review

Selenium (Se) is an essential element for humans and animals, which occurs ubiquitously in the environment. It is present in trace amounts in both organic and inorganic forms in marine and freshwater systems, soils, biomass and in the atmosphere. Low Se levels in certain terrestrial environments have resulted in Se deficiency in humans, while elevated Se levels in waters and soils can be toxic and result in the death of aquatic wildlife and other animals. Human dietary Se intake is largely governed by Se concentrations in plants, which are controlled by root uptake of Se as a function of soil Se concentrations, speciation and bioavailability. In addition, plants and microorganisms can biomethylate Se, which can result in a loss of Se to the atmosphere. The mobilization of Se across soil-plant-atmosphere interfaces is thus of crucial importance for human Se status. This review gives an overview of current knowledge on Se cycling with a specific focus on soil-plant-atmosphere interfaces. Sources, speciation and mobility of Se in soils and plants will be discussed as well as Se hyperaccumulation by plants, biofortification and biomethylation. Future research on Se cycling in the environment is essential to minimize the adverse health effects associated with unsafe environmental Se levels

Code for Graham et al. 2024, mSystems

Despite the explosion of soil metagenomic data, we lack a synthesized understanding of patterns in the distribution and functions of soil microorganisms. These patterns are critical to predictions of soil microbiome responses to climate change and resulting feedbacks that regulate greenhouse gas release from soils. To address this gap, we assay 1512 manually-curated soil metagenomes using complementary annotation databases, read-based taxonomy, and machine learning to extract multidimensional genomic fingerprints of global soil microbiomes. Our objective is to uncover novel biogeographical patterns of soil microbiomes across environmental factors and ecological biomes with high molecular resolution. We reveal shifts in the potential for (1) microbial nutrient acquisition across pH gradients; (2) stress, transport, and redox-based processes across changes in soil bulk density; and (3) greenhouse gas emissions across biomes. We also use an unsupervised approach to reveal a collection of soils with distinct genomic signatures, characterized by coordinated changes in soil organic carbon, nitrogen, and cation exchange capacity and in bulk density and clay content that may ultimately reflect soil environments with high microbial activity. Genomic fingerprints for these soils highlight the importance of resource scavenging, plant-microbe interactions, fungi, and heterotrophic metabolisms. Across all analyses, we observed phylogenetic coherence in soil microbiomes –– more closely related microorganisms tended to move congruently in response to soil factors. Collectively, the genomic fingerprints uncovered here present a basis for global patterns in the microbial mechanisms underlying soil biogeochemistry and help beget tractable microbial reaction networks for incorporation into process-based models of soil carbon and nutrient cycling.</p