Suchergebnisse

Introduction / Laurence Shore and Amy Pruden -- Steroid hormones and enzymes / Laurence Shore -- Steroid hormones generated by CAFOs / Laurence Shore -- Transport of steroids in surface waters / Laurence Shore -- Physiochemical characterization of steroid hormones in soil / Francis X.M. Casey -- Transport of steroids in soil under field conditions / Laurence S. Shore and Francis X.M. Casey -- Tracking sources of CAFO pollution / Laurence Shore -- Soil ecology and factors affecting biomass / Yosef Steinberger and Laurence Shore -- Occurrence and transport of antibiotics from CAFOs / Amy Pruden -- Antibiotic resistance associated with CAFOs / my Pruden -- Effects of steroid hormones on aquatic and soil organisms / Laurence Shore -- Organic compounds used in aquaculture / Thomas Heberer -- Organic compounds used in animal husbandry / Laurence Shore and Robert Wershaw -- Environmental impact and risk of CAFOs / Amy Pruden and Laurence Shore -- Management approaches to dealing with pharmaceuticals and hormones from CAFOs / Laurence Shore and Amy Pruden

Agricultural ecosystems are of special interest for monitoring the potential for antibiotic resistance to spread through the environment and contribute to human exposure. Molecular methods, which target DNA, RNA, and other molecular components of bacterial cells, present certain advantages for characterizing and quantifying markers of antibiotic resistance and their horizontal gene transfer. These include rapid, unambiguous detection of targets; consistent results; and avoidance of culture bias. However, molecular methods are also subject to limitations that are not always clearly addressed or taken into consideration in the interpretation of scientific data. In particular, DNA-based methods do not directly assess viability or presence within an intact bacterial host, but such information may be inferred based on appropriate experimental design or in concert with complementary methods. The purpose of this review is to provide an overview of existing molecular methods for tracking antibiotic resistance in agricultural ecosystems, to define their strengths and weaknesses, and to recommend a path forward for future applications of molecular methods and standardized reporting in the literature. This will guide research along the farm-to-fork continuum and support comparability of the growing number of studies in the literature in a manner that informs management decisions and policy development. ; Agriculture and Food Research Initiative Competitive Grant from USDA National Institute of Food and Agriculture [2013-68003-21256]; USDA NIFAUnited States Department of Agriculture (USDA) [2014-05280] ; This project was supported by Agriculture and Food Research Initiative Competitive Grant no. 2013-68003-21256 from the USDA National Institute of Food and Agriculture. Amy Pruden was also supported by USDA NIFA Grant no. 2014-05280. ; Public domain authored by a U.S. government employee

AbstractRemoval of contaminants of emerging concern (CECs) is an important consideration in potable reuse. The effectiveness of ozonation, biologically activated carbon (BAC) filtration, and granular activated carbon (GAC) adsorption was assessed in the removal of 96 CECs. During phase 1, O3/total organice carbon (TOC) was varied between 0 and 1.5. Ozone was successful in removing CECs, achieving a total CEC concentration of 20.5 μg/L at an O3/TOC of 1.5 compared with 70 μg/L in absence of ozone. CECs such as iohexol, meprobamate, sucralose and flame retardants, tris(2‐carboxyethyl)phosphine (TCEP), tris(1‐chloro‐2‐propyl) phosphate (TCPP), and tris(1,3‐dichloro‐2‐propyl)phosphate (TDCPP) were detected in the ozone effluent even at the highest ozone dose. BAC filters did not contribute measurably to CEC removal, while the 20‐min empty bed contact time (EBCT) GAC removed 57.6% of the influent CEC concentration, even though the adsorption capacity had been exerted through previous operation. During phase 2, the average O3/TOC ratio was 0.64, and the impact of new GAC media on CEC removal was studied. EBCT was maintained at 15 min for both GAC contactors, while the used GAC (133,600 bed volume [BV]) was replaced with new media in one GAC contactor. The GAC with new media removed CECs below the limit of quantitation, up to 10,000 BV, while removal decreased to 70% after 20,000 BV, with seven CECs—sucralose, iohexol, acesulfame‐k, meprobamate, cotinine, primidone, and acetaminophen—being detected. Ozone doses for CEC removal and BV needed for adsorption of CECs on activated carbon can be determined from this study. Thus, the results from this study can help design and optimize ozone, BAC, and GAC systems used for potable reuse to target the removal of specific CECs.

[Image: see text] Antimicrobial resistance (AMR) is a grand societal challenge with important dimensions in the water environment that contribute to its evolution and spread. Environmental monitoring could provide vital information for mitigating the spread of AMR; this includes assessing antibiotic resistance genes (ARGs) circulating among human populations, identifying key hotspots for evolution and dissemination of resistance, informing epidemiological and human health risk assessment models, and quantifying removal efficiencies by domestic wastewater infrastructure. However, standardized methods for monitoring AMR in the water environment will be vital to producing the comparable data sets needed to address such questions. Here we sought to establish scientific consensus on a framework for such standardization, evaluating the state of the science and practice of AMR monitoring of wastewater, recycled water, and surface water, through a literature review, survey, and workshop leveraging the expertise of academic, governmental, consulting, and water utility professionals.

AbstractBiological treatment is gaining ground as a means to enhance removal of total organic carbon (TOC) as part of a multi‐barrier treatment train for water reuse. Here we applied biodegradable dissolved organic carbon (BDOC) analysis to evaluate the extent of removal of various TOC fractions through a pilot‐scale water reuse train employing flocculation/sedimentation, ozone, biologically active carbon (BAC), and granular activated carbon (GAC). BDOC analysis highlighted GAC and ozone treatments as critical to non‐biodegradable dissolved organic carbon removal and the need to optimize BAC performance to maximize GAC adsorption capacity. BDOC analysis was further applied to benchmark process performance to operational conditions, such as empty bed contact time (EBCT), occurrence of nitrification, and operational upsets. The lower EBCT proved to be less resilient to nonideal conditions. Overall, BDOC analysis proved an asset for understanding and improving operation of ozone/BAC/GAC treatments for water reuse.

The presence of antibiotic drug residues, antibiotic resistant bacteria, and antibiotic resistance genes in agroecosystems has become a significant area of research in recent years and is a growing public health concern. While antibiotics are used in both human medicine and agricultural practices, the majority of their use occurs in animal production where historically they have been used for growth promotion, in addition to the prevention and treatment of disease. The widespread use of antibiotics and the application of animal wastes to agricultural lands play major roles in the introduction of antibiotic-related contamination into the environment. Overt toxicity in organisms directly exposed to antibiotics in agroecosystems is typically not a major concern because environmental concentrations are generally lower than therapeutic doses. However, the impacts of introducing antibiotic contaminants into the environment are unknown, and concerns have been raised about the health of humans, animals, and ecosystems. Despite increased research focused on the occurrence and fate of antibiotics and antibiotic resistance over the past decade, standard methods and practices for analyzing environmental samples are limited and future research needs are becoming evident. To highlight and address these issues in detail, this special collection of papers was developed with a framework of five core review papers that address the (i) overall state of science of antibiotics and antibiotic resistance in agroecosystems using a causal model, (ii) chemical analysis of antibiotics found in the environment, (iii) need for background and baseline data for studies of antibiotic resistance in agroecosystems with a decision-making tool to assist in designing research studies, as well as (iv) culture- and (v) molecular-based methods for analyzing antibiotic resistance in the environment. With a focus on the core review papers, this introduction summarizes the current state of science for analyzing antibiotics and antibiotic resistance in agroecosystems, discusses current knowledge gaps, and develops future research priorities. This introduction also contains a glossary of terms used in the core reivew papers of this special section. The purpose of the glossary is to provide a common terminology that clearly characterizes the concepts shared throughout the narratives of each review paper. ; Agriculture and Food Research Initiative Competitive from USDA National Institute of Food and Agriculture [2013-68003-21256] ; We thank all of the authors who contributed papers to this special section, which would not have been possible without their efforts. This project was supported by the Agriculture and Food Research Initiative Competitive Grant no. 2013-68003-21256 from the USDA National Institute of Food and Agriculture. ; Public domain authored by a U.S. government employee