Transport of steroid hormones in the vadose zone after land application of beef cattle manure

A variety of naturally occurring steroid hormones are regularly excreted by livestock, while additional steroid hormones have been used as growth promoters by the livestock industry. Depending on manure age and storage conditions, both groups of compounds are likely to be present during application to crops. Recent research suggests that some estrogens, androgens and progestagens in surface waters may originate from runoff after land application of livestock manure. Groundwater may also be impacted by livestock manure when used as a nutrient source to crops and may be indicated by excess nitrate in water. Few studies have been conducted to investigate the potential of steroid hormones contamination of groundwater. The objective of this study was to monitor leaching of steroid hormones and other compounds associated with livestock manure through the soil profile after land application of manure. The study was conducted near North Platte, Nebraska between April 2008 and July 2011 on a silt loam soil. Leachate was collected at the bottom of 2.4 meter deep monolithic percolation lysimeters to sample water leached beneath plots fertilized with manure. Soil samples were also collected from surrounding irrigated field plots. Treatments consisted of two manure handling procedures (stockpiling and composting) and a check receiving no manure application. Manure stored from a previous year’s cattle feeding pen study was sampled and analyzed for steroid hormone content. Manure was applied to the lysimeters and adjacent plot areas in April 2008 at a rate satisfying the nitrogen requirements of winter wheat planted in the fall of 2007 and 2008 followed by soybeans planted in the spring of 2010 and 2011. Leachate from the lysimeters and soil samples (down to 2.4 meter depth) from surrounding areas were collected periodically during the study. Laboratory analyses of manure, soil, and leachate samples used liquid chromatography tandem mass spectrometry to identify 17 steroid hormones and metabolites. Progesterone, estrone, beta-zearalenol and 4-androstenedione were detected at varying concentrations in both composted (1.6-8.4 nanograms per gram) and stockpiled (3.7-11.4 nanograms per gram) manure. Steroid hormones and related compounds were detected in only 5 percent of the leachate samples. The greatest detected concentration was 20 nanograms per liter of natural progesterone in a leachate sample from a lysimeter treated with stockpiled manure. Steroid hormones or metabolites were detected in 10 percent of the soil samples. Seventy four percent of the detections in the soil samples were in the top half (top 1.2 meter) of the sampled soil depth. 17beta-estradiol was detected the most in the soil samples (4 percent) with a maximum concentration of 4.3 nanograms per gram in a plot treated with composted manure. No synthetic steroids were detected in any of the soil or leachate samples. The low detection of steroid hormones in the soil and leachate samples suggests that, while some hormones may move through the soil, most are readily degraded or adsorbed after manure application. Additional research is required to more clearly identify the mechanisms that control the environmental fate and transport of steroid hormones through the soil

Effect of composting on the fate of steroids in beef cattle manure

In this study, the fate of steroid hormones in beef cattle manure composting is evaluated. The fate of 16 steroids and metabolites was evaluated in composted manure from beef cattle administered growth promotants and from beef cattle with no steroid hormone implants. The fate of estrogens (primary detected as estrone), androgens, progesterone, and the fusarium metabolite and implant a-zearalanol were monitored in manure compost piles. First-order decay rates were calculated for steroid half-lives in compost and ranged from 8 days for androsterone to 69 days for 4-androsterone. Other steroid concentration data did not fit first-order decay models which may indicate that other microbial processes may result in steroid production or synthesis in composting systems. We demonstrate that composting is an effective strategy to remove steroid hormones from manure. Total steroid hormone removal in composted beef cattle manure ranged from 79-87%

Use of a surrogate to evaluate the impact of tillage on the transport of steroid hormones from manure-amended agricultural field

Beef feedlot manure distributed to row crop production areas is a potential surface water contaminant source of the steroid hormones commonly used in beef cattle production. This article reports on research conducted at the University of Nebraska Haskell Agricultural Laboratory near Concord, Nebraska, in July 2009. Manure, collected from beef feedlot pens, was stockpiled for ten months prior to application to a row crop field. Previous research identified that the detection frequency of steroid hormones in beef manure varies greatly. Thus, a surrogate (17 alpha-ethynylestradiol, EE2) was applied at a rate of 75 g per ha to ensure detectable concentrations in surface runoff samples. EE2 was applied directly to beef cattle manure and to bare soil. The EE2 and manure were either incorporated using a single disk treatment (T) or left on the soil surface in a no-till practice (NT). A rainfall simulation experiment was conducted 24 h after manure and EE2 incorporation using a factorial design consisting of tillage, manure, and EE2 treatments. Runoff samples were collected at 5 min intervals during a 30 min runoff period for each plot. Results indicated 96 percent less EE2 mass transport from disk tilled plots compared to no-till. The greatest loss of EE2 was 156 and 6 mg per ha from no-till and disked plots, respectively. Results of this study showed that a single-pass disk tillage treatment can limit the overland transport of steroid hormones from crop production areas

Transport of steroid hormones in the vadose zone after land application of beef cattle manure

A variety of naturally occurring steroid hormones are regularly excreted by livestock, while additional steroid hormones have been used as growth promoters by the livestock industry. Depending on manure age and storage conditions, both groups of compounds are likely to be present during application to crops. Recent research suggests that some estrogens, androgens and progestagens in surface waters may originate from runoff after land application of livestock manure. Groundwater may also be impacted by livestock manure when used as a nutrient source to crops and may be indicated by excess nitrate in water. Few studies have been conducted to investigate the potential of steroid hormones contamination of groundwater. The objective of this study was to monitor leaching of steroid hormones and other compounds associated with livestock manure through the soil profile after land application of manure. The study was conducted near North Platte, Nebraska between April 2008 and July 2011 on a silt loam soil. Leachate was collected at the bottom of 2.4 meter deep monolithic percolation lysimeters to sample water leached beneath plots fertilized with manure. Soil samples were also collected from surrounding irrigated field plots. Treatments consisted of two manure handling procedures (stockpiling and composting) and a check receiving no manure application. Manure stored from a previous year’s cattle feeding pen study was sampled and analyzed for steroid hormone content. Manure was applied to the lysimeters and adjacent plot areas in April 2008 at a rate satisfying the nitrogen requirements of winter wheat planted in the fall of 2007 and 2008 followed by soybeans planted in the spring of 2010 and 2011. Leachate from the lysimeters and soil samples (down to 2.4 meter depth) from surrounding areas were collected periodically during the study. Laboratory analyses of manure, soil, and leachate samples used liquid chromatography tandem mass spectrometry to identify 17 steroid hormones and metabolites. Progesterone, estrone, beta-zearalenol and 4-androstenedione were detected at varying concentrations in both composted (1.6-8.4 nanograms per gram) and stockpiled (3.7-11.4 nanograms per gram) manure. Steroid hormones and related compounds were detected in only 5 percent of the leachate samples. The greatest detected concentration was 20 nanograms per liter of natural progesterone in a leachate sample from a lysimeter treated with stockpiled manure. Steroid hormones or metabolites were detected in 10 percent of the soil samples. Seventy four percent of the detections in the soil samples were in the top half (top 1.2 meter) of the sampled soil depth. 17beta-estradiol was detected the most in the soil samples (4 percent) with a maximum concentration of 4.3 nanograms per gram in a plot treated with composted manure. No synthetic steroids were detected in any of the soil or leachate samples. The low detection of steroid hormones in the soil and leachate samples suggests that, while some hormones may move through the soil, most are readily degraded or adsorbed after manure application. Additional research is required to more clearly identify the mechanisms that control the environmental fate and transport of steroid hormones through the soil