The widespread use of nano-enabled agrochemicals in agriculture for remediating soil and improving nutrient use efficiency of organic and chemical fertilizers is increasing continuously with limited understanding on their potential risks. Recent studies suggested that nanoparticles (NPs) are harmful to soil organisms and their stimulated nutrient cycling in agriculture. However, their toxic effects under natural input farming systems are just at its infancy. Here, we aimed to examine the harmful effects of nano-agrochemical zinc oxide (ZnONPs) to poultry (PM) and farmyard manure (FYM) C and N cycling in soil-plant systems. These manures enhanced microbial counts, CO₂ emission, N mineralization, spinach yield and N recovery than control (unfertilized). Soil applied ZnONPs increased labile Zn in microbial biomass, conferring its consumption and thereby reduced the colony-forming bacterial and fungal units. Such effects resulted in decreasing CO₂ emitted from PM and FYM by 39 and 43%, respectively. Further, mineralization of organic N was reduced from FYM by 32%, and PM by 26%. This process has considerably decreased the soil mineral N content from both manure types and thereby spinach yield and plant N recoveries. In the ZnONPs amended soil, only about 23% of the applied total N from FYM and 31% from PM was ended up in plants, whereas the respective fractions in the absence of ZnONPs were 33 and 53%. Hence, toxicity of ZnONPs should be taken into account when recommending its use in agriculture for enhancing nutrient utilization efficiency of fertilizers or soil remediation purposes.

The industrial production of insects for waste management or as a protein source is becoming vital to our society. Large volumes of manure are produced by concentrated animal facilities around the globe that must be managed, utilized, and disposed of properly. Flies offer a partial solution with their abilities to reduce these wastes and heavy metal pollutants. Meat and crop proteins are being supplemented by insect proteins for many feeds across the globe, yet science-based studies behind the mass-rearing of insects are still in their infancy. In the current study, the percent change in the composition of nutrients, heavy metals, and fiber, in dairy, poultry, and swine manure degraded by either black soldier fly (BSF) or house fly (HF) larvae was explored. Pre-digested and post-digested manure samples were collected from four independent studies that differed in production scale (number of larvae and feeding regimen): 1) BSF small-scale (100 larvae fed incrementally), 2) HF small-scale (100 larvae fed incrementally), 3) BSF large-scale (10,000 larvae fed a single time), and 4) HF large-scale (4,000 larvae fed a single time). Results indicate that nitrogen is a key nutrient impacted by larval digestion of manure by both species, regardless of scale. However, scale significantly impacted reductions of other nutrients, as did the type of manure in which the insects were reared. Ultimately, this study demonstrated that manure type and rearing scale impact the ability of BSF and HF larvae to reduce nutrients and heavy metals in manure, and thus insect management procedures need to be congruent with production emphases of the insects for waste management or protein products. Failure to take scale into consideration could lead to inaccurate assumptions related to industrialized efforts on this topic.

The human pathogenic bacteria (HPB) in animal feces may disseminate to agricultural soils with their land application as organic fertilizer. However, the knowledge about the impacts of different sources and rates of animal manures on the temporal changes of soil HPB remains limited, which hamper our ability to estimate the potential risks of their land application. Here, we constructed an HPB database including 565 bacterial strains. By blasting the 16 S rRNA gene sequences against the database we explored the occurrence and fate of HPB in soil microcosms treated with two rates of swine, poultry or cattle manures. A total of 30 HPB were detected in all of manure and soil samples. Poultry manure at the high level obviously improved the abundance of soil HPB. The application of swine manure could introduce concomitant HPB into the soils. Of which, Pseudomonas syringae pv. syringae B728a and Escherichia coli APEC O78 may deserve more attention because of their survival for a few days in manured soils and being possible hosts of diverse antibiotic resistance genes (ARGs) as revealed by co-occurrence pattern. Bayesian source tracking analysis showed that the HPB derived from swine manure had a higher contribution to soil pathogenic communities than those from poultry or cattle manures in early days of incubation. Mantel test together with variation partitioning analysis suggested that bacterial community and soil physicochemical properties were the dominant factors determining the profile of HPB and contributed 64.7% of the total variations. Overall, our results provided experimental evidence that application of animal manures could facilitate the potential dissemination of HPB in soil environment, which should arouse sufficient attention in agriculture practice and management to avoid the threat to human health.

Baseline emission values of greenhouse gases were not well established for commercial poultry barns in cold regions, including Canada, due to a lack of well-designed field studies. Emission factors of carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O), were acquired for a commercial broiler barn and cage-layer barn in the Canadian Prairies climate. Between March 2015 and February 2016, monthly measurements throughout the year for the layer barn and over 6 flocks for the broiler barn, and diurnal measurements in the mild, warm, and cold seasons for both barns were conducted, respectively. The ventilation rate was estimated based on a CO₂ mass balance method; thus CO₂ emissions were quantified by the CIGR (2002) models. The CH₄ and N₂O emissions present at low levels from global perspective for both barns; the cold climate proved to be a major reason for the lower CH₄ emission from the layer barn. Considerable seasonal effect was observed only for N₂O emissions from the broiler barn, and for CH₄ and N₂O emissions from the layer barn, both with higher emissions in the mild and warm seasons than in the cold season. The big diurnal variations of CO₂ emissions for the layer barn demonstrated the uncertainty of the seasonal results by snapshot measurements and correction factors (from −20.9% to −22.5%) were obtained. Besides, the difference of CH₄ and N₂O concentrations and emissions as well as CO₂ concentrations between best-case (the first day after manure removal) and worst-case conditions (the last day before manure removal) was not obvious for the layer barn. Additionally, changes of temperature and ventilation rate were likely to have more impact on N₂O emission for the broiler barn and more impact on CH₄ emission for the layer barn than on the other two gas emissions, both with positive correlations.

Hexabromocyclododecane (HBCD) is commonly used in commercial products and factories. HBCDs can be detected in the air, bioaccumulated deposits, water, soil, sediments, and in biota and foodstuffs in the food-chain because they are not chemically bound to the polymer. We determined the levels of α-, β-, and γ-HBCDs in 270 foodstuffs and the doses of HBCDs Taiwanese are normally exposed to. We also wanted to create a strategy of risk management for HBCDs based on margins of exposure (MOE). HBCDs were frequently detectible in fish, seafood, and poultry. Their highest concentrations were in fish, oil, poultry, and livestock. The highest estimated daily intake was in 0- to 3-year-olds (1.576 ng/kg/day), and lower in 3- to 6- (1.064 ng/kg/day), 6- to 12- (0.899 ng/kg/day), and lowest in 12- to 16- (0.632 ng/kg/day) year-olds. The exposure doses to HBCDs indicated no health concern for Taiwanese. Except for fish, significant concentrations of α- and γ-HBCDs were detected in many other foodstuffs, which might indicate that exposure to HBCD is a relatively recent problem. Therefore, one goal of a management policy should be to follow-up the flow direction of HBCDs in Taiwan.

Food products are inevitably contaminated by flame retardants throughout their lifecycle (i.e., during production, use, and disposal). In order to evaluate the dietary intake of legacy and emerging halogenated flame retardants (HFRs) in typical market food in China, we investigate the distribution and profile of 27 legacy polybrominated diphenyl ethers (PBDEs) and 16 emerging HFRs (EHFRs) in 9 food categories (meat, poultry, aquatic food, eggs, dairy products, cereals, vegetables, nuts and fruits, and sugar). A total of 105 food samples collected from three markets in Nanjing, eastern China were included for evaluation. The highest concentrations of PBDEs and EHFRs were found in aquatic foods (means of 0.834 ng/g wet weight (ww) and 0.348 ng/g ww, respectively), and the lowest concentrations were found in sugar (means of 0.020 ng/g ww for PBDEs and 0.014 ng/g ww for EHFRs). 2,2′,4-tribromodiphenyl ether (BDE-17), a legacy HFR, and hexabromobenzene (HBBz), an EHFR, were the predominant pollutants in the investigated food samples. Concentrations of HBBz and 2,3-dibromopropyl tribromophenyl ether (DPTE) were comparable to those of some PBDEs in certain food samples. The concentrations of the total EHFRs and total PBDEs found in animal-based food samples were significantly greater than those in plant-based food samples. Comparison of the estimated total dietary intake of HFRs and their corresponding non-cancer reference dose (United States Environmental Protection Agency) suggests a low overall health risk. To the best of our knowledge, the present study is the first to simultaneously determine 27 PBDEs and 16 EHFRs in representative foods from Chinese markets. BDE-17, HBBz, and DPTE were the predominant congeners among the 43 investigated HFRs and meat and aquatic foods were the primary sources of PBDEs and EHFRs to the total local dietary intake.

Concentrated animal-feeding operations (CAFOs) are considered a source of airborne human pathogens and antibiotic resistance genes. Although bacterial abundance and diversity have been well studied, limited information on the size distribution of bioaerosols has prevented a clear understanding of the health effects of exposure to bioaerosols from CAFOs. Here, different sizes of particles were sampled from the inside and outside of atmospheric environments of layer and broiler feeding operations using 8-stage Andersen samplers. The quantitative real-time polymerase chain reaction (qPCR) and 16S rDNA-based sequencing were used to analyze the characteristics of biological abundance and diversity, respectively, according to size. The results indicated that size-related differences occurred in terms of airborne bacterial richness, diversity, and concentration at poultry-feeding operations. The richness of biological genera in the urban atmospheric environment was lower than in concentrated poultry-feeding operations. The biological diversity of airborne bacterial genera, including genera associated with potential pathogens, varied according to size. The bacterial lineages of bioaerosols present in the 7 size stages for layers clustered apart from those for broilers, suggesting that the type of poultry house is a more important factor than the particle size in shaping the microbial communities. In most cases, the concentrations of the 16S rDNA, Escherichia coli, tetW, and tetL genes increased as the particle size increased, with the geometric mean diameters varying from 4.7 to 5.8 μm. These results regarding the size-related differences in the diversity and abundance of bioaerosols will facilitate a better understanding of the potential health impact on both poultry and humans working in such environments.

In this paper, a poultry slaughterhouse wastewater (PSW) was treated in terms of chemical oxygen demand (COD) and color reduction using electro-Fenton (EF) technique under response surface methodology (RSM). The effects of five significant independent variables such as reaction time, pH, H2O2/Fe2+ molar ratio, current density, volume ratio of H2O2/PSW (ml/l) were investigated on the COD and color removal. Experimental data were optimized by Box-Behnken design (BBD) and RSM. The optimum conditions were experimentally found at pH of 4.38, reaction time of 55.60 min, H2O2/Fe2+ molar ratio of 3.73, current density of 74.07 mA/cm2, volume ratio of H2O2/PSW of 1.63 ml/l for 92.37%COD removal and at pH of 3.39, reaction time of 49.22 min, H2O2/Fe2+ molar ratio of 3.62, current density of 67.90 mA/cm2, volume ratio of H2O2/PSW of 1.44 ml/l for 88.06% color removal.

Land application of animal manure is a common agricultural practice potentially leading to dispersal and propagation of antibiotic resistance genes (ARGs) in environmental settings. However, the fate of resistome in agro-ecosystems over time following application of different manure sources has never been compared systematically. Here, soil microcosm incubation was conducted to compare effects of poultry, cattle and swine manures spiked with or without the antibiotic tylosin on the temporal changes of soil ARGs. The high-throughput quantitative PCR detected a total of 185 unique ARGs, with Macrolide-Lincosamide-Streptogramin B resistance as the most frequently encountered ARG type. The diversity and abundance of ARGs significantly increased following application of manure and manure spiked with tylosin, with more pronounced effects observed in the swine and poultry manure treatments than in the cattle manure treatment. The level of antibiotic resistance gradually decreased over time in all manured soils but was still significantly higher in the soils treated with swine and poultry manures than in the untreated soils after 130 days’ incubation. Tylosin-amended soils consistently showed higher abundances of ARGs than soils treated with manure only, suggesting a strong selection pressure of antibiotic-spiked manure on soil ARGs. The relative abundance of ARGs had significantly positive correlations with integrase and transposase genes, indicative of horizontal transfer potential of ARGs in manure and tylosin treated soils. Our findings provide evidence that application of swine and poultry manures might enrich more soil ARGs than cattle manure, which necessitates the appropriate treatment of raw animal manures prior to land application to minimise the spread of environmental ARGs.

This study investigated potential ammonia impacts on a sand dune nature reserve 600 m upwind of an intensive poultry unit. Ammonia concentrations and total nitrogen deposition were measured over a calendar year. A series of ammonia and nitrogen exposure experiments using dune grassland species were conducted in controlled manipulations and in the field. Ammonia emissions from the intensive poultry unit were detected up to 2.8 km upwind, contributing to exceedance of critical levels of ammonia 800 m upwind and exceedance of critical loads of nitrogen 2.8 km upwind. Emissions contributed 30% of the total N load in parts of the upwind conservation site. In the nitrogen exposure experiments, plants showed elevated tissue nitrogen contents, and responded to ammonia concentrations and nitrogen deposition loads observed in the conservation site by increasing biomass. Estimated long-term impacts suggest an increase in the soil carbon pool of 9% over a 50-year timescale.