Occurrence of Trenbolone Acetate Metabolites in Simulated Confined Animal Feeding Operation (CAFO) Runoff

Abstract

Metabolites of androgenic synthetic growth promoters used at confined animal feeding operations (CAFOs) pose a demonstrated ecological risk. To evaluate the transport of trenbolone acetate (TBA) metabolites from beef cattle CAFOs, rainfall simulation experiments were conducted at the University of California, Davis, research CAFO. Steroid concentrations in solid and aqueous samples from the research CAFO and solids samples from a commercial CAFO were analyzed by gas chromatography-tandem mass spectrometry. The data indicate that 17α-trenbolone (17α-TBOH), 17β-trenbolone (17β-TBOH), and trendione (TBO), the three primary TBA metabolites, occur in soils and runoff. Soils at the research CAFO contained up to 8.2 (±1.1) ng/g-dw of 17α-TBOH and 1.2 (±0.1) ng/g-dw of 17β-TBOH, with slightly higher (~20 ng/g-dw) 17α-TBOH concentrations observed in commercial CAFO soils. In simulated runoff, 17α-TBOH concentrations of 1-350 ng/L and TBO concentrations from 1-170 ng/L were observed. The metabolite 17β-TBOH intermittently occurred in runoff samples at 5-26 ng/L and may be correlated to anaerobic soils. Metabolite concentrations observed in CAFO runoff correspond to 5-15% of potential maximum steroid concentrations predicted by mass balances. First order transformation rates of 0.028/day (25 day half-life) were estimated for 17α-TBOH in CAFO soils. Results suggest that ecologically relevant concentrations of TBA metabolites can be mobilized from CAFO surfaces in storm runoff and may lead to receiving water concentrations at or above ecological effects thresholds for a very limited number of discharge scenarios.

Low concentrations of 17β-trenbolone induce female-to-male reversal and mortality in the frog Pelophylax nigromaculatus

“…In the literature, 17␤-trenbolone concentrations in surface water generally vary at ng/L levels (Gall et al, 2011;Liu et al, 2011;Webster et al, 2012). In the present study, the nominal test concentrations ranged from 0.1 to 10 g/L, with an actual concentration range of 0.091-9.867 g/L.…”

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

“…30−35 For comparison, equivalent stocking densities for CAFOs range from 100 to 1000 AUM/ha (40−400 AUM/ ac). 22 While the AUM quantifies pasture carrying capacity for management purposes, the grazing intensity determines the time animals spend on a single pasture. Under the highest grazing intensities, cattle consume all available forage in 1−5 days and must be rotated to different pastures.…”

“…The 4-L samples were collected and processed in the field/ laboratory for TBA metabolites, nutrients (i.e., total ammonia, nitrate, nitrite, and orthophosphate), dissolved organic carbon (DOC), total coliforms, and E. coli as previously described. 22,25,27,28 All coliform and most nutrient and DOC samples were analyzed within 24 h (see SI for details). TBA metabolite samples (1 L) were pressure filtered (0.7 μm AP40 filters, Millipore, Billerica, MA), spiked with 1 mL of 100 μg/L (i.e., 100 ng) of 17β-TBOH-d 3 internal standard in methanol, and immediately loaded onto 6 mL C-18 solid phase extraction (SPE) cartridges (Restek, Bellefonte, PA, U.S.A.; Q < 10 mL/ min) within 4 h of sample collection.…”

“…11,16−18 Although no observed adverse effects levels (NOAELs) are not reported for TBA metabolites (i.e., 17α-TBOH, 17β-TBOH, and trendione [TBO]), a reasonable estimate is 1 ng/L, similar to other synthetic steroids. 11,19,20 Concentrations of 17α-TBOH and 17β-TBOH in runoff from TBA-implanted cattle can be as high as 350 and 270 ng/L, respectively, 21,22 although detections in agricultural runoff, including from manure-fertilized fields, and receiving waters are typically sporadic (i.e., 0−15% of all samples) with variable concentrations (e.g., no detect160 ng/L). 3,21−26 While these values may represent concentration upper bounds in agricultural runoff, little data currently link steroid occurrence and concentration to system characteristics and operational practices (e.g., stocking density, implant mass, etc.…”

Coupled reversion and stream-hyporheic exchange processes increase environmental persistence of trenbolone metabolites

“…17a-TBOH represents about 95% of identifiable excreted metabolites by mass 4 , although a number of unidentified TBA metabolites likely exist. Given the typical application rates of TBA to cattle, mass balance calculations predict that thousands of ng l À 1 are possible in agricultural runoff 5,6 , although concentrations observed in receiving waters are typically far lower when detected 7,8 . Field observations have documented 1,700 ng l À 1 17a-TBOH in manure lagoons 9 , and 55 ± 22 ng g À 1 in solid manure and surface soils 10 .…”