Managing waste from confined animal feeding operations in the United States: the need for sanitary reform

Co-Processing Agricultural Residues and Wet Organic Waste Can Produce Lower-Cost Carbon-Negative Fuels and Bioplastics

Scalable, low-cost biofuel and biochemical production can accelerate progress on the path to a more circular carbon economy and reduced dependence on crude oil. Rather than producing a single fuel product, lignocellulosic biorefineries have the potential to serve as hubs for the production of fuels, production of petrochemical replacements, and treatment of high-moisture organic waste. A detailed techno-economic analysis and life-cycle greenhouse gas assessment are developed to explore the cost and emission impacts of integrated corn stover-to-ethanol biorefineries that incorporate both codigestion of organic wastes and different strategies for utilizing biogas, including onsite energy generation, upgrading to bio-compressed natural gas (bioCNG), conversion to poly(3-hydroxybutyrate) (PHB) bioplastic, and conversion to single-cell protein (SCP). We find that codigesting manure or a combination of manure and food waste alongside process wastewater can reduce the biorefinery's total costs per metric ton of CO₂ equivalent mitigated by half or more. Upgrading biogas to bioCNG is the most cost-effective climate mitigation strategy, while upgrading biogas to PHB or SCP is competitive with combusting biogas onsite.

MoS2 nanosheets loaded on collapsed structure zeolite as a hydrophilic and efficient photocatalyst for tetracycline degradation and synergistic mechanism

In this study, MoS₂@Z photocatalysts were synthesized by combining ultrasonic and hydrothermal methods, and used for the degradation of tetracycline. The structure characteristics and photocatalytic degradation mechanism of photocatalysts were also systematically investigated. The obtained MoS₂@Z-5 exhibits the highest photo-degradation efficiency of tetracycline (87.23%), which is 3.58 times more than alkali-modified zeolite (24.34%) and 1.80 times more than pure MoS₂ (48.53%). Furthermore, the MoS₂@Z-5 showed significant stability in three times photocatalytic recycles and the removal efficiency only decrease by 9.03%. Crystal structure and micromorphology analysis show modified zeolite with collapsed structure can regulate the morphology of nano-MoS₂ and make MoS₂ appear fault structure, which can expose more active sites. In addition, low Si/Al ratio zeolite increases the hydrophilia of MoS₂@Z-5. Reactive-species-trapping experiments show that the hole is the main reactive oxidizing species. The superior photo-degradation efficiency is mainly attributed to outstanding hydrophilia, exposure of the edge active sites, and efficient separation of photogenerated charge and holes. A possible photocatalytic mechanism and degradation pathways of tetracycline were proposed. The results indicate that MoS₂@Z-5 may become an efficient, stable, and promising photocatalyst in tetracycline wastewater treatment.

Environmental Injustice and Industrial Chicken Farming in Maryland

Maryland’s growing chicken industry, including concentrated animal feeding operations (CAFOs) and meat processing plants, raises a number of concerns regarding public health and environmental justice. Using hot spot analysis, we analyzed the totality of Maryland’s CAFOs and meat processing plants and those restricted to the Eastern Shore to assess whether communities of color and/or low socioeconomic status communities disproportionately hosted these types of facilities at the census tract level. We used zero-inflated regression modeling to determine the strength of the associations between environmental justice variables and the location of CAFOs and meatpacking facilities at the State level and on the Eastern Shore. Hot spot analyses demonstrated that CAFO hot spots on the Eastern Shore were located in counties with some of the lowest wealth in the State, including the lowest ranking county—Somerset. Zero-inflated regression models demonstrated that increases in median household income across the state were associated with a 0.04-unit reduction in CAFOs. For every unit increase in the percentage of people of color (POC), there was a 0.02-unit increase in meat processing facilities across the state. The distribution of CAFOs and meat processing plants across Maryland may contribute to poor health outcomes in areas affected by such production, and contribute to health disparities and health inequity.

Climate change, extreme events, and increased risk of salmonellosis: foodborne diseases active surveillance network (FoodNet), 2004-2014

BACKGROUND

Infections with nontyphoidal Salmonella cause an estimated 19,336 hospitalizations each year in the United States. Sources of infection can vary by state and include animal and plant-based foods, as well as environmental reservoirs. Several studies have recognized the importance of increased ambient temperature and precipitation in the spread and persistence of Salmonella in soil and food. However, the impact of extreme weather events on Salmonella infection rates among the most prevalent serovars, has not been fully evaluated across distinct U.S. regions.

METHODS

To address this knowledge gap, we obtained Salmonella case data for S. Enteriditis, S. Typhimurium, S. Newport, and S. Javiana (2004-2014; n = 32,951) from the Foodborne Diseases Active Surveillance Network (FoodNet), and weather data from the National Climatic Data Center (1960-2014). Extreme heat and precipitation events for the study period (2004-2014) were identified using location and calendar day specific 95^th percentile thresholds derived using a 30-year baseline (1960-1989). Negative binomial generalized estimating equations were used to evaluate the association between exposure to extreme events and salmonellosis rates.

RESULTS

We observed that extreme heat exposure was associated with increased rates of infection with S. Newport in Maryland (Incidence Rate Ratio (IRR): 1.07, 95% Confidence Interval (CI): 1.01, 1.14), and Tennessee (IRR: 1.06, 95% CI: 1.04, 1.09), both FoodNet sites with high densities of animal feeding operations (e.g., broiler chickens and cattle). Extreme precipitation events were also associated with increased rates of S. Javiana infections, by 22% in Connecticut (IRR: 1.22, 95% CI: 1.10, 1.35) and by 5% in Georgia (IRR: 1.05, 95% CI: 1.01, 1.08), respectively. In addition, there was an 11% (IRR: 1.11, 95% CI: 1.04-1.18) increased rate of S. Newport infections in Maryland associated with extreme precipitation events.

CONCLUSIONS

Overall, our study suggests a stronger association between extreme precipitation events, compared to extreme heat, and salmonellosis across multiple U.S. regions. In addition, the rates of infection with Salmonella serovars that persist in environmental or plant-based reservoirs, such as S. Javiana and S. Newport, appear to be of particular significance regarding increased heat and rainfall events.

Synergetic Effects during Co-Pyrolysis of Sheep Manure and Recycled Polyethylene Terephthalate

Continuous growth in energy demand and plastic waste production are two global emerging issues that require development of clean technologies for energy recovery and solid waste disposal. Co-pyrolysis is an effective thermochemical route for upgrading waste materials to produce energy and value added products. In this study, co-pyrolysis of sheep manure (SM) and recycled polyethylene terephthalate (PET) was studied for the first time in a thermogravimetric analyzer (TGA) in the temperature range of 25-1000 °C with heating rates of 10-30-50 °C min^-1 under a nitrogen atmosphere. The synergetic effects of co-pyrolysis of two different waste feedstock were investigated. The kinetic parameters are determined using the Flynn-Wall-Ozawa (FWO) model. The results revealed that the mean values of apparent activation energy for the decomposition of sheep manure into a recycled polyethylene terephthalate blend are determined to be 86.27, 241.53, and 234.51 kJ/mol, respectively. The results of the kinetic study on co-pyrolysis of sheep manure with plastics suggested that co-pyrolysis is a viable technique to produce green energy.

Antibiotic Resistance in Recreational Waters: State of the Science

Ambient recreational waters can act as both recipients and natural reservoirs for antimicrobial resistant (AMR) bacteria and antimicrobial resistant genes (ARGs), where they may persist and replicate. Contact with AMR bacteria and ARGs potentially puts recreators at risk, which can thus decrease their ability to fight infections. A variety of point and nonpoint sources, including contaminated wastewater effluents, runoff from animal feeding operations, and sewer overflow events, can contribute to environmental loading of AMR bacteria and ARGs. The overall goal of this article is to provide the state of the science related to recreational exposure and AMR, which has been an area of increasing interest. Specific objectives of the review include (1) a description of potential sources of antibiotics, AMR bacteria, and ARGs in recreational waters, as documented in the available literature; (2) a discussion of what is known about human recreational exposures to AMR bacteria and ARGs, using findings from health studies and exposure assessments; and (3) identification of knowledge gaps and future research needs. To better understand the dynamics related to AMR and associated recreational water risks, future research should focus on source contribution, fate and transport-across treatment and in the environment; human health risk assessment; and standardized methods.

Effects of concentrated poultry operations and cropland manure application on antibiotic resistant Escherichia coli and nutrient pollution in Chesapeake Bay watersheds

Manure from poultry operations is typically applied to nearby cropland and may affect nutrient loading and the spread of antibiotic resistance (ABR). We analyzed the concentrations of nitrogen and phosphorus and the occurrence of ABR in Escherichia coli (E. coli) and extra-intestinal pathogenic E. coli isolates from streams draining 15 small (<19 km²) watersheds of the Chesapeake Bay with contrasting levels of concentrated poultry operations. Total nitrogen and nitrate plus nitrite concentrations increased with poultry barn density with concentrations two and three times higher, respectively, in watersheds with the highest poultry barn densities compared to those without poultry barns. Analysis of N and O isotopes in nitrate by mass spectrometry showed an increase in the proportion of ¹⁵N associated with an increase in barn density, suggesting that the nitrate associated with poultry barns originated from manure. Phosphorus concentrations were not correlated with barn density. Antibiotic susceptibility testing of putative E. coli isolates was conducted using the disk diffusion method for twelve clinically important antibiotics. Of the isolates tested, most were completely susceptible (67%); 33% were resistant to at least one antibiotic, 24% were resistant to ampicillin, 13% were resistant to cefazolin, and 8% were multi-drug resistant. Resistance to three cephalosporin drugs was positively associated with an index of manure exposure estimated from poultry barn density and proportion of cropland in a watershed. The proportion of E. coli isolates resistant to cefoxitin, cefazolin, and ceftriaxone, broad-spectrum antibiotics important in human medicine, increased by 18.9%, 16.9%, and 6.2%, respectively, at the highest estimated level of manure exposure compared to watersheds without manure exposure. Our results suggest that comparisons of small watersheds could be used to identify geographic areas where remedial actions may be needed to reduce nutrient pollution and the public health risks of ABR bacteria.

Pilot study of global endocrine disrupting activity in Iowa public drinking water utilities using cell-based assays

Some anthropogenic substances in drinking water are known or suspected endocrine disrupting compounds (EDCs), but EDCs are not routinely measured. We conducted a pilot study of 10 public drinking water utilities in Iowa, where common contaminants (e.g., pesticides) are suspected EDCs. Raw (untreated) and finished (treated) drinking water samples were collected in spring and fall and concentrated using solid phase extraction. We assessed multiple endocrine disrupting activities using novel mammalian cell-based assays that express nuclear steroid receptors (aryl hydrocarbon [AhR], androgenic [AR], thyroid [TR], estrogenic [ER] and glucocorticoid [GR]). We quantified each receptor's activation relative to negative controls and compared activity by season and utility/sample characteristics. Among 62 samples, 69% had AhR, 52% AR, 3% TR, 2% ER, and 0% GR activity. AhR and AR activities were detected more frequently in spring (p =0 .002 and < 0.001, respectively). AR activity was more common in samples of raw water (p =0 .02) and from surface water utilities (p =0 .05), especially in fall (p =0 .03). Multivariable analyses suggested spring season, surface water, and nitrate and disinfection byproduct concentrations as determinants of bioactivity. Our results demonstrate that AR and AhR activities are commonly found in Iowa drinking water, and that their detection varies by season and utility/sample characteristics. Screening EDCs with cell-based bioassays holds promise for characterizing population exposure to diverse EDCs mixtures.

From Genes to Nitrogen Removal: Determining the Impacts of Poultry Industry Wastewater on Tidal Creek Denitrification

The intensification of the poultry industry in the last decades has led to a sharp increase in the number of animal processing plants discharging wastewater to water bodies. These discharges may have a significant effect on environmental quality and on important ecosystem functions, such as denitrification. We conducted a seasonal survey and a microcosm experiment in an impacted and a reference tidal creek to investigate the impacts of wastewater discharge from a poultry processing plant on sedimentary microbial communities, denitrification activity, and nitrate removal. Denitrification potential was measured using slurry incubations, and the microbial community was examined with 16S rDNA MiSeq sequencing and quantitative polymerase chain reaction of denitrification genes. The lowest denitrification rates were observed in the impacted creek, especially near the wastewater discharge, and denitrification inhibition by impacted creek water was clearly observed in the microcosm experiment. Denitrification rates were associated with changes in the microbial community composition and gene abundance. Estimated nitrate removal was lower in the impacted creek, and higher chlorophyll levels were observed in a downstream coastal bay through remote sensing. This study demonstrates denitrification inhibition by wastewater discharge from a poultry processing plant with potential consequences to coastal eutrophication.

Rapid Health Impact Assessment of a Proposed Poultry Processing Plant in Millsboro, Delaware

In 2013, Allen Harim Foods purchased the former site of a Vlasic Pickle plant in Millsboro, Delaware, and proposed to convert the site into a poultry processing plant that would process approximately two million birds weekly. This generated concerns about the proposed plant’s potential to impact health and quality of life among residents. We conducted a rapid health impact assessment (HIA) of the proposed plant to assess baseline environmental health issues in the host community and projected impacts. The scoping and baseline assessment revealed social, economic, and health disparities in the region. We also determined that residents in the area were already underserved and overburdened with pollution from multiple environmental hazards near the proposed plant including two sites contaminated with hazardous wastes, a power plant, and another poultry processing plant. The projected size and amount of poultry to be processed at the plant would likely cause increased levels of air, soil and water pollution, additional odor issues, and increased traffic and related pollution and safety issues. The information generated from the HIA formed the basis of a campaign to raise awareness about potential problems associated with the new facility and to foster more engagement of impacted residents in local decision-making about the proposed plant. In the end, the HIA helped concerned residents oppose the new poultry processing plant. This case study provides an example of how HIAs can be used as a tool to educate residents, raise awareness about environmental justice issues, and enhance meaningful engagement in local environmental decision-making processes.

Applying an environmental public health lens to the industrialization of food animal production in ten low- and middle-income countries

Background

Industrial food animal production (IFAP) is characterized by dense animal housing, high throughput, specialization, vertical integration, and corporate consolidation. Research in high-income countries has documented impacts on public health, the environment, and animal welfare. IFAP is proliferating in some low- and middle-income countries (LMICs), where increased consumption of animal-source foods has occurred alongside rising incomes and efforts to address undernutrition. However, in these countries IFAP’s negative externalities could be amplified by inadequate infrastructure and resources to document issues and implement controls.

Methods

Using UN FAOSTAT data, we selected ten LMICs where food animal production is expanding and assessed patterns of IFAP growth. We conducted a mixed methods review to explore factors affecting growth, evidence of impacts, and information gaps; we searched several databases for sources in English, Spanish, and Portuguese. Data were extracted from 450+ sources, comprising peer-reviewed literature, government documents, NGO reports, and news articles.

Results

In the selected LMICs, not only has livestock production increased, but the nature of expansion appears to have involved industrialized methods, to varying extents based on species and location. Expansion was promoted in some countries by explicit government policies. Animal densities, corporate structure, and pharmaceutical reliance in some areas mirrored conditions found in high-income countries. There were many reported weaknesses in regulation and capacity for enforcement surrounding production and animal welfare. Global trade increasingly influences movement of and access to inputs such as feed. There was a nascent, compelling body of scientific literature documenting IFAP’s negative environmental and public health externalities in some countries.

Conclusions

LMICs may be attracted to IFAP for economic development and food security, as well as the potential for increasing access to animal-source foods and the role these foods can play in alleviating undernutrition. IFAP, however, is resource intensive. Industrialized production methods likely result in serious negative public health, environmental, and animal welfare impacts in LMICs. To our knowledge, this is the first systematic effort to assess IFAP trends through an environmental public health lens for a relatively large group of LMICs. It contributes to the literature by outlining urgent research priorities aimed at informing national and international decisions about the future of food animal production and efforts to tackle global undernutrition.

Sustainable Valorization of Animal Manure and Recycled Polyester: Co-pyrolysis Synergy

In this study sustainable valorization of cattle manure, recycled polyester, and their blend (1:1 wt.%) were examined by the thermogravimetric analysis (TGA) method. Pyrolysis tests were performed at 10, 30, and 50 °C/min heating rate from room temperature to 1000 °C under a nitrogen environment with a flow of 100 cm3/min. Kinetics of decomposition were analyzed by using Flynn–Wall–Ozawa (FWO) method. Based on activation energies and conversion points, a single region was established for recycled polyester while three regions of pyrolysis were obtained for cattle manure and their blend. Comparison between experimental and theoretical profiles indicated synergistic interactions during co-pyrolysis in the high temperature region. The apparent activation energies calculated by FWO method for cattle manure, recycled polyester. and their blend were 194.62, 254.22 and 227.21 kJ/mol, respectively. Kinetics and thermodynamic parameters, including E, ΔH, ΔG, and ΔS, have shown that cattle manure and recycled polyester blend is a remarkable feedstock for bioenergy.

"Ag-Gag" Laws: Evolution, Resurgence, and Public Health Implications

The term "ag-gag" refers to state laws that intentionally limit public access to information about agricultural production practices, particularly livestock production. Originally created in the 1990s, these laws have recently experienced a resurgence in state legislatures. We discuss the recent history of ag-gag laws in the United States and question whether such ag-gag laws create a "chilling effect" on reporting and investigation of occupational health, community health, and food safety concerns related to industrial food animal production. We conclude with a discussion of the role of environmental and occupational health professionals to encourage critical evaluation of how ag-gag laws might influence the health, safety, and interests of day-to-day agricultural laborers and the public living proximal to industrial food animal production.

Evaluating biological plausibility in supporting evidence for action through systematic reviews in public health

OBJECTIVES

The objective of this research was to develop and test methods for accessing and evaluating information on the biological plausibility of observed associations between exposures or interventions and outcomes to generate scientific evidence for action consistent with practice in systematic reviews.

STUDY DESIGN

To undertake this research, we used the example of the observed associations between antimicrobial use in food animals and increased risks of human exposures to antimicrobial-resistant pathogens of zoonotic origin.

METHODS

We conducted a scoping search using terms related to biological plausibility or mechanism to identify key references. As recommended by these references, we also used expert consultation with researchers and a public health informationist. We used their recommendations, which included expert consultation, to identify mechanisms relevant to biological plausibility of the association we selected to test. We used the reviews conducted by the World Health Organization (WHO) Guidelines Development Group in support of reducing antimicrobial use in food animal production to populate our model for assessing biological plausibility.

RESULTS

We were able to develop a transparent model for biological plausibility based on the adverse outcome pathway used in toxicology and ecology. We were also able to populate this model using the WHO reviews.

CONCLUSIONS

This analysis of biological plausibility used transparent and validated methods to assess the evidence used in systematic reviews based on the observational studies accessed through searches of the scientific literature. Given the importance of this topic in systematic reviews and evidence-based decision-making, further research is needed to define and test the methodological approaches to access and properly evaluate information from the scientific literature.

Pathogens transmitted in animal feces in low- and middle-income countries

Animals found in close proximity to humans in low-and middle-income countries (LMICs) harbor many pathogens capable of infecting humans, transmissible via their feces. Contact with animal feces poses a currently unquantified-though likely substantial-risk to human health. In LMIC settings, human exposure to animal feces may explain some of the limited success of recent water, sanitation, and hygiene interventions that have focused on limiting exposure to human excreta, with less attention to containing animal feces. We conducted a review to identify pathogens that may substantially contribute to the global burden of disease in humans through their spread in animal feces in the domestic environment in LMICs. Of the 65 potentially pathogenic organisms considered, 15 were deemed relevant, based on burden of disease and potential for zoonotic transmission. Of these, five were considered of highest concern based on a substantial burden of disease for which transmission in animal feces is potentially important: Campylobacter, non-typhoidal Salmonella (NTS), Lassa virus, Cryptosporidium, and Toxoplasma gondii. Most of these have a wide range of animal hosts, except Lassa virus, which is spread through the feces of rats indigenous to sub-Saharan Africa. Combined, these five pathogens cause close to one million deaths annually. More than half of these deaths are attributed to invasive NTS. We do not estimate an overall burden of disease from improperly managed animal feces in LMICs, because it is unknown what proportion of illnesses caused by these pathogens can be attributed to contact with animal feces. Typical water quantity, water quality, and handwashing interventions promoted in public health and development address transmission routes for both human and animal feces; however, sanitation interventions typically focus on containing human waste, often neglecting the residual burden of disease from pathogens transmitted via animal feces. This review compiles evidence on which pathogens may contribute to the burden of disease through transmission in animal feces; these data will help prioritize intervention types and regions that could most benefit from interventions aimed at reducing human contact with animal feces.

Carbon dioxide assisted thermal decomposition of cattle excreta

To develop the environmentally benign thermo-chemical process, this study placed great emphasis on the influence of CO₂ on pyrolysis of cattle excreta for energy recovery. To this end, this study evaluates the possible enhanced energy recovery from cattle excreta using CO₂ as reaction medium/feedstock in the thermal degradation of cattle excreta. The enhanced generation of CO in the presence of CO₂ reached up to 15.15mol% (reference value: 0.369mol%) at 690°C, which was equivalent to ~4000 times more generation of CO. In addition to the enhanced generation of CO, the enhanced generation of H₂ and CH₄ in the thermal degradation of cattle excreta in CO₂. Thus, the findings of this study revealed two genuine roles of CO₂: 1) enhanced thermal cracking of volatile organic carbons (VOCs) evolved from the thermal degradation of cattle excreta and 2) direct reaction between VOCs and CO₂ via gas phase reaction.

Veterinary pharmaceuticals in aqueous systems and associated effects: an update

Environmental studies have shown that pharmaceuticals can contaminate aqueous matrices, such as groundwater, surface water, sediment as well as aquatic flora and fauna. Effluents from sewage and wastewater treatment plants, pharmaceutical industries and hospitals have been implicated in such contamination. Recent studies have however revealed significant concentrations of pharmaceuticals in wastewater from animal facilities in proximal aquatic habitats. Furthermore, epidemiological studies have shown a consistent positive correlation between exposure to some drugs of veterinary importance and increased adverse effects in aquatic biota largely due to induction of endocrine disruption, antibiotic resistance, neurotoxicity, genotoxicity and oxidative stress. The aquatic habitats and associated biota are important in the maintenance of global ecosystem and food chain. For this reason, anything that compromises the integrity and functions of the aquatic environment may lead to major upset in the world's ecosystems. Therefore, knowledge about this route of exposure cannot be neglected and monitoring of their occurrence in the environment is required. This review focuses on scientific evidence that link the presence of pharmaceuticals in aqueous matrices to animal production facilities and presents means to reduce the occurrence of veterinary pharmaceutical residues in the aquatic habitats.

Environmental health impacts of feeding crops to farmed fish

Half of the seafood consumed globally now comes from aquaculture, or farmed seafood. Aquaculture therefore plays an increasingly important role in the global food system, the environment, and human health. Traditionally, aquaculture feed has contained high levels of wild fish, which is unsustainable for ocean ecosystems as demand grows. The aquaculture industry is shifting to crop-based feed ingredients, such as soy, to replace wild fish as a feed source and allow for continued industry growth. This shift fundamentally links seafood production to terrestrial agriculture, and multidisciplinary research is needed to understand the ecological and environmental health implications. We provide basic estimates of the agricultural resource use associated with producing the top five crops used in commercial aquaculture feed. Aquaculture's environmental footprint may now include nutrient and pesticide runoff from industrial crop production, and depending on where and how feed crops are produced, could be indirectly linked to associated negative health outcomes. We summarize key environmental health research on health effects associated with exposure to air, water, and soil contaminated by industrial crop production. Our review also finds that changes in the nutritional content of farmed seafood products due to altered feed composition could impact human nutrition. Based on our literature reviews and estimates of resource use, we present a conceptual framework describing the potential links between increasing use of crop-based ingredients in aquaculture and human health. Additional data and geographic sourcing information for crop-based ingredients are needed to fully assess the environmental health implications of this trend. This is especially critical in the context of a food system that is using both aquatic and terrestrial resources at unsustainable rates.

Industrial Food Animal Production and Community Health

Industrial food animal production (IFAP) is a source of environmental microbial and chemical hazards. A growing body of literature suggests that populations living near these operations and manure-applied crop fields are at elevated risk for several health outcomes. We reviewed the literature published since 2000 and identified four health outcomes consistently and positively associated with living near IFAP: respiratory outcomes, methicillin-resistant Staphylococcus aureus (MRSA), Q fever, and stress/mood. We found moderate evidence of an association of IFAP with quality of life and limited evidence of an association with cognitive impairment, Clostridium difficile, Enterococcus, birth outcomes, and hypertension. Distance-based exposure metrics were used by 17/33 studies reviewed. Future work should investigate exposure through drinking water and must improve exposure assessment with direct environmental sampling, modeling, and high-resolution DNA typing methods. Investigators should not limit study to high-profile pathogens like MRSA but include a broader range of pathogens, as well as other disease outcomes.

Food System Policy, Public Health, and Human Rights in the United States

The US food system functions within a complex nexus of social, political, economic, cultural, and ecological factors. Among them are many dynamic pressures such as population growth, urbanization, socioeconomic inequities, climate disruption, and the increasing demand for resource-intensive foods that place immense strains on public health and the environment. This review focuses on the role that policy plays in defining the food system, particularly with regard to agriculture. It further examines the challenges of making the food supply safe, nutritious, and sustainable, while respecting the rights of all people to have access to adequate food and to attain the highest standard of health. We conclude that the present US food system is largely unhealthy, inequitable, environmentally damaging, and insufficiently resilient to endure the impacts of climate change, resource depletion, and population increases, and is therefore unsustainable. Thus, it is imperative that the US embraces policy reforms to transform the food system into one that supports public health and reflects the principles of human rights and agroecology for the benefit of current and future generations.

Learning from agriculture: understanding low-dose antimicrobials as drivers of resistome expansion

Antimicrobial resistance is a growing public health challenge worldwide, with agricultural use of antimicrobials being one major contributor to the emergence and dissemination of antimicrobial resistance (AMR). Globally, most antimicrobials are used in industrial food animal production, a major context for microbiomes encountering low-doses or subtherapeutic-levels of antimicrobial agents from all mechanistic classes. This modern practice exerts broad eco-evolutionary effects on the gut microbiome of food animals, which is subsequently transferred to animal waste. This waste contains complex constituents that are challenging to treat, including AMR determinants and low-dose antimicrobials. Unconfined storage or land deposition of a large volume of animal waste causes its wide contact with the environment and drives the expansion of the environmental resistome through mobilome facilitated horizontal genet transfer. The expanded environmental resistome, which encompasses both natural constituents and anthropogenic inputs, can persist under multiple stressors from agriculture and may re-enter humans, thus posing a public health risk to humans. For these reasons, this review focuses on agricultural antimicrobial use as a laboratory for understanding low-dose antimicrobials as drivers of resistome expansion, briefly summarizes current knowledge on this topic, highlights the importance of research specifically on environmental microbial ecosystems considering AMR as environmental pollution, and calls attention to the needs for longitudinal studies at the systems level.

Availability of information about airborne hazardous releases from animal feeding operations

Introduction

Air from animal feeding operations (AFOs) has been shown to transport numerous contaminants of public health concern. While federal statutes like the Emergency Planning and Community Right-to-Know Act (EPCRA) generally require that facilities report hazardous releases, AFOs have been exempted from most of these requirements by the U.S. Environmental Protection Agency (EPA). We assessed the availability of information about AFO airborne hazardous releases following these exemptions.

Methods

We submitted public records requests to 7 states overlapping with or adjacent to the Chesapeake Bay watershed for reports of hazardous releases made by AFOs under EPCRA. From the records received, we calculated the proportion of AFOs in each state for which ≥1 reports were available. We also determined the availability of specific types of information required under EPCRA. The numbers of AFOs permitted under the Clean Water Act (CWA) or analogous state laws, as determined from permitting databases obtained from states, were used as denominators.

Results

We received both EPCRA reports and permitting databases from 4 of 7 states. Across these 4 states, the mean proportion of AFOs for which ≥1 EPCRA reports were available was 15% (range: 2-33%). The mean proportions of AFOs for which the name or identity of the substance released, ≥1 estimates of quantity released, and information about nearby population density and sensitive populations were available were 15% (range: 2-33%), 8% (range: 0-22%), and 14% (range: 2-8%), respectively.

Discussion

These results suggest that information about the airborne hazardous releases of a large majority of AFOs is not available under federal law in the states that we investigated. While the results cannot be attributed to specific factors by this method, attention to multiple factors, including revision of the EPA’s exemptions, may increase the availability of information relevant to the health of populations living or working near AFOs.

Restrictions on antimicrobial use in food animal production: an international regulatory and economic survey

Background

The administration of antimicrobial drugs to food animals at low doses for extended durations for growth promotion and disease prevention has been linked to the global health crisis of antimicrobial resistance. Internationally, multiple jurisdictions have responded by restricting antimicrobial use for these purposes, and by requiring a veterinary prescription to use these drugs in food animals. Opponents of these policies have argued that restrictions have been detrimental to food animal production where they have been adopted.

Methods

We surveyed the antimicrobial use policies of 17 political jurisdictions outside of the United States with respect to growth promotion, disease prevention, and veterinary oversight, and reviewed the available evidence regarding their production impacts, including measures of animal health. Jurisdictions were included if they were a top-five importer of a major U.S. food animal product in 2011, as differences between the policies of the U.S. and other jurisdictions may lead to trade barriers to U.S. food animal product exports. Jurisdictions were also included if information on their policies was publicly available in English. We searched the peer-reviewed and grey literatures and corresponded with jurisdictions’ U.S. embassies, regulators, and local experts.

Results

Jurisdictions were categorized by whether they prohibit use of antimicrobials for growth promotion and/or use of antimicrobials without a veterinary prescription. Of the 17 jurisdictions surveyed, six jurisdictions have prohibited both types of use, five jurisdictions have prohibited one use but not the other use, and five jurisdictions have not prohibited either use, while information was not available for one jurisdiction. Data on the production impacts of these prohibitions were limited, although available data, especially from Denmark and Sweden, suggest that restrictions on growth promotion use can be implemented with minimal production consequences.

Conclusions

A majority of leading U.S. trade partners have more stringent policies regarding antibiotic use and veterinary oversight in food animal production. Available data suggest that restrictions on growth promotion may not be detrimental to production in the long run, although additional research could be useful. There is evidence that discordance between the U.S. and other jurisdictions with respect to antimicrobial use in food animals may be detrimental to U.S. access to export markets for food animal products. The available economic evidence strengthens the rationale for restricting antimicrobial use in U.S. food animals.

Investigating the role of state and local health departments in addressing public health concerns related to industrial food animal production sites

Objectives

Evidence of community health concerns stemming from industrial food animal production (IFAP) facilities continues to accumulate. This study examined the role of local and state health departments in responding to and preventing community-driven concerns associated with IFAP.

Methods

We conducted semi-structured qualitative interviews with state and county health department staff and community members in eight states with high densities or rapid growth of IFAP operations. We investigated the extent to which health concerns associated with IFAP sites are reported to health departments, the nature of health departments’ responses, and barriers to involvement.

Results

Health departments’ roles in these matters are limited by political barriers, lack of jurisdiction, and finite resources, expertise, and staff. Community members reported difficulties in engaging health departments on these issues.

Conclusions

Our investigation suggests that health departments frequently lack resources or jurisdiction to respond to health concerns related to IFAP sites, resulting in limited engagement. Since agencies with jurisdiction over IFAP frequently lack a health focus, increased health department engagement may better protect public health.

An ecological perspective on U.S. industrial poultry production: the role of anthropogenic ecosystems on the emergence of drug-resistant bacteria from agricultural environments

The industrialization of food animal production, specifically the widespread use of antimicrobials, not only increased pressure on microbial populations, but also changed the ecosystems in which antimicrobials and bacteria interact. In this review, we argue that industrial food animal production (IFAP) is appropriately defined as an anthropogenic ecosystem. This paper uses an ecosystem perspective to frame an examination of these changes in the context of U.S. broiler chicken production. This perspective emphasizes multiple modes by which IFAP has altered microbiomes and also suggests a means of generating hypotheses for understanding and predicting the ecological impacts of IFAP in terms of the resistome and the flow of resistance within and between microbiomes.