This study was conducted to analyze the genetic variability of Escherichia coli from domesticated animal wastes for microbial source tracking (MST) application in fecal contaminated shellfish growing waters of Xiangshan Bay, East China Sea. (GTG)₅ primer was used to generate 1363 fingerprints from E. coli isolated from feces of known 9 domesticated animal sources around this shellfish culture area. Jackknife analysis of the complete (GTG)₅-PCR DNA fingerprint library indicated that isolates were assigned to the correct source groups with an 84.28% average rate of correct classification. Based on one-year source tracking data, the dominant sources of E. coli were swine, chickens, ducks and cows in this water area. Moreover, annual and spatial changes of E. coli concentrations and host sources may affect the level and distribution of zoonotic pathogen species in waters. Our findings will further contribute to preventing fecal pollution in aquatic environments and quality control of shellfish.

Nitrous oxide (N₂O) direct soil emissions from agriculture are often estimated using the default IPCC emission factor (EF) of 1%. However, a large variation in EFs exists due to differences in environment, crops and management. We developed an approach to determine N₂O EFs that depend on N-input sources and environmental factors. The starting point of the method was a monitoring study in which an EF of 1% was found. The conditions of this experiment were set as the reference from which the effects of 16 sources of N input, three soil types, two land-use types and annual precipitation on the N₂O EF were estimated. The derived EF inference scheme performed on average better than the default IPCC EF. The use of differentiated EFs, including different regional conditions, allows accounting for the effects of more mitigation measures and offers European countries a possibility to use a Tier 2 approach.

The integrated modelling system INITIATOR was applied to a landscape in the northern part of the Netherlands to assess current nitrogen fluxes to air and water and the impact of various agricultural measures on these fluxes, using spatially explicit input data on animal numbers, land use, agricultural management, meteorology and soil. Average model results on NH₃ deposition and N concentrations in surface water appear to be comparable to observations, but the deviation can be large at local scale, despite the use of high resolution data. Evaluated measures include: air scrubbers reducing NH₃ emissions from poultry and pig housing systems, low protein feeding, reduced fertilizer amounts and low-emission stables for cattle. Low protein feeding and restrictive fertilizer application had the largest effect on both N inputs and N losses, resulting in N deposition reductions on Natura 2000 sites of 10% and 12%, respectively.

The aim of this study is to illustrate the importance of farm scale heterogeneity on nitrogen (N) losses in agricultural landscapes. Results are exemplified with a chain of N models calculating farm-N balances and distributing the N-surplus to N-losses (volatilisation, denitrification, leaching) and soil-N accumulation/release in a Danish landscape. Possible non-linearities in upscaling are assessed by comparing average model results based on (i) individual farm level calculations and (ii) averaged inputs at landscape level. Effects of the non-linearities that appear when scaling up from farm to landscape are demonstrated. Especially in relation to ammonia losses the non-linearity between livestock density and N-loss is significant (p > 0.999), with around 20–30% difference compared to a scaling procedure not taking this non-linearity into account. A significant effect of farm type on soil N accumulation (p > 0.95) was also identified and needs to be included when modelling landscape level N-fluxes and greenhouse gas emissions.

The diffusive gradients in thin films (DGT) technique was evaluated in modelling wheat (Triticum aestivum) arsenic toxicity using a dataset of As-contaminated soil samples (n=28) collected from former sheep dip sites. Above ground wheat biomass from a 21-day early growth bioassay was adopted as the response variable and the dose–response relationships were modelled using the three-parameter sigmoid equation. The DGT-derived effective soil solution As to P concentration ratios corresponded strongly to the differences in the response variable. With a single sample identified as an outlier, the 95% confidence interval for the effective soil solution As/P molar concentration ratio which resulted in a 50% reduction in the response (EC50) was 0.168–0.360. While the DGT-derived soil measure of As/P ratio was shown as a promising phytotoxicity predictor, the influence of P nutrition on the dose–response relationship deserves further consideration.

A wide variety of veterinary antibiotics (VAs) has been detected in environmental water samples, and this is of potential environmental concern due to their adverse effects. In particular, the potential for development of antibiotic-resistant bacteria has raised social concerns leading to intensive investigation regarding the influence of antibiotics on human and ecosystem health. One of the main sources of antibiotic effluence to the environment is livestock manures that often contain elevated levels of VAs that survive normal digestive procedures following medication in animal husbandry because unlike human waste, waste generated on farms does not undergo tertiary wastewater treatment, and consequently, the concentration of antibiotics entering the environment is expected to be larger from farming practices. Animal feed is often supplemented with VAs to promote growth and parasite resistance in the medicated animals, and this practice typically resulted in higher use of VAs and consequential excretion from livestock through urine and feces. The excretion rate varied depending on the type of VA used with around 75, 90, and 50–100% being excreted for chlortetracycline, sulfamethazine, and tyolsin, respectively. The excreted VAs that initially present in livestock manures were degraded more than 90% when proper composting practice was used, and hence, this can be employed as a management strategy to decrease VA environmental loads. The reduction of VA concentrations during composting was mainly attributed to abiotic processes rather than biotic degradation. The VAs released to soils by the application of manure and manure-based composts can be degraded or inactivated to various degrees through abiotic process such as adsorption to soil components. Depending on the antibiotic species and soil properties, residues can be transferred to groundwater and surface water through leaching and runoff and can potentially be taken up by plants.