Private wells in Ireland and elsewhere have been shown to be prone to microbial contamination with the main suspected sources being practices associated with agriculture and domestic wastewater treatment systems (DWWTS). While the microbial quality of private well water is commonly assessed using faecal indicator bacteria, such as Escherichia coli, such organisms are not usually source-specific, and hence cannot definitively conclude the exact origin of the contamination. This research assessed a range of different chemical contamination fingerprinting techniques (ionic ratios, artificial sweeteners, caffeine, fluorescent whitening compounds, faecal sterol profiles and pharmaceuticals) as to their use to apportion contamination of private wells between human wastewater and animal husbandry wastes in rural areas of Ireland. A one-off sampling and analysis campaign of 212 private wells found that 15% were contaminated with E. coli. More extensive monitoring of 24 selected wells found 58% to be contaminated with E. coli on at least one occasion over a 14-month period. The application of fingerprinting techniques to these monitored wells found that the use of chloride/bromide and potassium/sodium ratios is a useful low-cost fingerprinting technique capable of identifying impacts from human wastewater and organic agricultural contamination, respectively. The artificial sweetener acesulfame was detected on several occasions in a number of monitored wells, indicating its conservative nature and potential use as a fingerprinting technique for human wastewater. However, neither fluorescent whitening compounds nor caffeine were detected in any wells, and faecal sterol profiles proved inconclusive, suggesting limited suitability for the conditions investigated.

Avermectin (AVM) has been widely used in agriculture and animal husbandry based on its broad spectrum of effective anthelmintic activity and specificity targets. However, AVM induction of cytotoxicity in human liver is largely unknown. In this study, we investigate the cytotoxic effects of AVM on HepG2 cells in vitro. The results revealed that AVM inhibited the viability of HepG2 cells and enhanced apoptosis. Established assays of cytotoxicity were performed to characterize the mechanism of AVM toxicity on HepG2 cells. Typical apoptosis morphological changes were shown in AVM-treatment cells including chromatin condensation and DNA fragmentation. We demonstrated that AVM-induced apoptosis of HepG2 cells were mediated by generated ROS. Moreover, a decrease in mitochondrial membrane potential (MMP) and up-regulating the Bax/Bcl-2 ratio, resulted in a release of cytochrome-c as well as activation of caspase-9/-3. In conclusion, our experimental results show that AVM has a potential threat to human health which may be induce apoptosis of human hepatocyte cells via caspase-dependent mitochondrial pathways.

Chicken organs, animal feed, droppings, and ambient air were sampled at a farm in Beijing to determine the concentrations of hexachlorocyclohexane isomers (HCHs) and dichlorodiphenyltrichloroethane and metabolites (DDTs). Mean fresh weight concentrations of HCHs and DDTs were 0.122 ± 0.061 ng/g and 0.051 ± 0.038 ng/g in the muscles. These values are 1-2 orders of magnitude lower than those reported in China in 1980. Contaminated feed was the main source of HCHs and DDTs. Only 12.8% of HCH and 3.3% of DDT of the amount consumed were excreted. Accumulated quantities of HCHs and DDTs increased during growth. However, concentrations of HCHs and DDTs did not increase because of dilution from rapid growth. Based on the observed residual levels in mature chicken and the average diet of residents of China, the contributions from chicken and egg consumption to per capita daily intake of HCHs and DDTs were 487% and 88% of those of fish consumption.

A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the simultaneous analysis of 6 ectoparasiticides – 2 synthetic pyrethroids (deltamethrin, cypermethrin) and 4 macrocyclic lactones (abamectin, doramectin, ivermectin and eprinomectin) in biosolids. The method was used to investigate the occurrence of these ectoparasiticides in beef cattle feedlot wastes in Australia from 5 commercial feedlot operations which employ varying waste management practices. Deltamethrin and cypermethrin were not detected in any of the samples while abamectin, ivermectin, doramectin and eprinomectin were detected in some of the samples with concentrations ranging from 1 to 36 μg/kg dry weight (d.w.) freeze dried feedlot waste. Levels of macrocyclic lactones detected in the feedlot wastes varied and were dependent on sample type. The effect of seasonal variations and waste management practices were also investigated in this study.

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.

This study investigated if atmospheric ammonia (NH3) pollution around a sheep farm influences the photosynthetic performance of the lichens Evernia prunastri and Pseudevernia furfuracea. Thalli of both species were transplanted for up to 30 days in a semi-arid region (Crete, Greece), at sites with concentrations of atmospheric ammonia of ca. 60 μg/m3 (at a sheep farm), ca. 15 μg/m3 (60 m from the sheep farm) and ca. 2 μg/m3 (a remote area 5 km away). Lichen photosynthesis was analysed by the chlorophyll a fluorescence emission to identify targets of ammonia pollution. The results indicated that the photosystem II of the two lichens exposed to NH3 is susceptible to this pollutant in the gas-phase. The parameter PIABS, a global index of photosynthetic performance that combines in a single expression the three functional steps of the photosynthetic activity (light absorption, excitation energy trapping, and conversion of excitation energy to electron transport) was much more sensitive to NH3 than the FV/FM ratio, one of the most commonly used stress indicators.

Due to the abusive usage of antibiotics in animal husbandry, a large amount of residual antibiotics has been released into the environment, therein posing great threat against both environment security and public health. Therefore, it is of great significance to investigate the toxicity of antibiotics on the widely-applied bioindicator-earthworm. In this work, the physiological parameters and the intestinal bacteria community of Metaphire guillelmi were monitored simultaneously to evaluate their sensitivity to the tetracycline (TC) exposure. As expected, the antioxidant enzyme activity and coelomocyte apoptosis acted fairly well as biomarkers for the TC toxicity. In contrast, the intestinal bacteria of Metaphire guillelmi responded varyingly to different TC doses. When TC concentration increased from 0 to 35.7 μg cm⁻², the percentage of the Proteobacteria phylum declined significantly from 85.5% to 34.4%, while the proportions of the Firmicutes, Planctomycetes and Atinomycete phyla clearly increased (p < 0.05). Meanwhile, the levels of TC resistance genes tetA, tetC, and tetW increased with the increasing TC concentration, in contrast to the declined abundance in denitrifying genes nirS and nosZ (p < 0.05). By analyzing the correlation between the antioxidant enzyme activity and the dominant intestinal bacteria in the worm gut, it is interesting to found that the four dominant bacteria genera Mesorhizobium, Aliihoeflea, Romboutsia, and Nitrospira are the promising bioindicator of TC stress due to their sensitive response. This work shed novel light on evaluating the ecotoxicological risks posed by residual TC in environment by using a combination of physiological parameters and intestinal bacterial activity in earthworms.