Setbacks are prescribed distances from surface waters within which manure application is not allowed. Little information is available concerning the retention of swine slurry constituents in soil and crop residue materials within setback areas. This study was conducted to measure the retention of selected constituents within a setback area following the upslope application of swine slurry and the introduction of simulated rainfall. The no-till cropland site had a slope gradient of 4.9% and a mean winter wheat residue cover of 7.73 Mg ha⁻¹. Soil and vegetative samples were collected on 3.7 m wide by 23.2 m long plots with and without the addition of slurry. Slurry was added at the 0–4.9 m distance on selected plots, and simulated rainfall was then applied to the entire plot area during two separate events. Soil cores and vegetative samples were collected from each plot at distances of 2.44, 5.18, 7.92, 11.0, 14.0, 17.1, and 20.1 m from the upper plot border. The soil cores were separated into 0–10, 10–20, and 20–30 cm depth increments. Significant increases in soil concentrations of chloride, nitrate, phosphorus, and zinc were found both within and downslope from the slurry application area. Residue materials located both within and downslope from the slurry application area contained significantly increased concentrations of boron, calcium, copper, magnesium, sulfur, and zinc. When estimating the downslope transport of constituents contained in swine slurry, contributions from runoff, soil, and residue should all be considered.

In this study, light intensities of Aliivibrio fischeri obtained from soil suspension and its filtrate were compared using field soils contaminated with heavy metals. The soils collected from rice paddy and forest had different soil textures with either high or low silt/clay content. The correlation between soil toxicity and soil solution toxicity for A. fischeri showed a high linearity in sandy soils with the slope of 0.586 (determination coefficient; R² = 0.709). Meanwhile, a lower correlation in silty/clay soils with the slope of 0.154 (R² = 0.067) was observed. When a solid phase bioluminescence inhibition test is carried out using soil suspension with a high silt/clay content, a large amount of A. fischeri seems to adhere to microparticles and/or microaggregates. It may result in the change of light intensity (i.e., distorted toxicity test result) that could not be corrected by the modified basic solid phase test protocol, and thus the toxicity is likely to be overestimated. Such alteration in the light intensity could be partially overcome using a regression equation accounting for microbial loss by adhesion. With the correction for microbial adhesion, the correlation between soil toxicity and soil solution toxicity in the selected soil samples with high silt/clay contents increased from 0.182 (R² = 0.130) to 0.571 (R² = 0.602). It is expected that soil toxicity can be evaluated through the prediction of soil solution toxicity after the proper correction of microparticles effects.

Waste stabilization ponds (WSP) used to treat dairy shed effluent hold significant loads of recoverable nutrients in the sludge. Land application of this pond sludge over grazing paddocks is a potential alternative to chemical fertilizer. Desludging of WSPs can further enhance the nutrient removal efficiency of the WSP and thereby improve the water quality of the WSP effluent and limit accumulation of phosphorus (P) in WSPs. The aim of this study was to investigate the changes in the nutrient content of soil after land application of pond sludge (PS) collected from WSP over grazing paddocks. In particular, P fractions (e.g. labile P as H₂O-P and NaHCO₃-P, and stable P as NaOH-P and HCl-P) were analysed in pond sludge applied soil collected from grazed paddocks. It was found that the application of PS significantly changed the composition of phosphorus in the soil compared with a control paddock that was not treated with PS. The inorganic P in the paddocks treated with pond sludge was 605 mg/kg, which was significantly higher than 67 mg/kg observed in the control paddock. Similarly, the soil treated with pond sludge exhibited increased P fractions of 245%, 36%, 47% and 3000% in terms of H₂O-P, NaHCO₃-P, NaOH-P and HCl-P, respectively, compared with the control paddock. The results of labile and stable P fractions in the soil samples show that PS could be a viable alternative to other forms of commercial fertilizers and a sustainable source of P for the dairy grazing paddocks.

There is a worldwide concern regarding soil pollution caused by contamination of petroleum hydrocarbon, released during oil processing or production. Once a spill occurs, it disturbs the marine and freshwater ecosystem and greatly threatens human health. It usually requires complex technologies to remove it from soil. Petroleum hydrocarbons contain a range of chemicals which are extremely toxic and carcinogenic in nature. Although physical or chemical methods are widely employed for remediation, numerous studies revealed that bioremediation is a sustainable approach. Bioremediation is often preferred as clean and carbon-neutral solution. This review aims to provide series of sustainable solution for petroleum hydrocarbon degradation without exploiting the environment as well as opportunity to reuse treated media. Integrated and enhanced bioremediation technologies are more effective than natural degradation of petroleum hydrocarbons in terms of shorter time period and percent removal efficiency. It comprehensively illustrates bioremediation assisted with bacteria, fungi, and algae either by integrated technologies or by enhancing the process. Most recent application methods of petroleum hydrocarbon bioremediation (in situ and ex situ) are also reported. There is dire need to explore different cost-effective biotechnological resources for degradation of petroleum hydrocarbon by the screening of novel microbial strains or by the creation of genetically engineered bacteria to survive in harsh environment.

Citarum River is the largest natural stream in West Java, Indonesia, flowing across an area of 6614 km². About 3000 industries discharge their wastewater into the stream, affecting almost 19 million people who live along the river. Considering the perseverance and the prospective toxicity of microplastics (MPs), investigating their concentrations in this river is critical to help illustrate the exposure of the risks to the residents of the area and beyond. This study was focused on identifying the MPs concentrations in the water, sediment, and milkfish (Chanos chanos). A volume-reduce method by using manta trawl was used to take water samples. Sediment and milkfish samples were taken using a grab sampling method. Digestion of fish was using Fenton oxidation method according to weighted ratio (1:5) and H₂O₂ 30% (w/v). The average MPs concentration in the river was 0.0574 ± 0.025 particles/m³; in the seawater ponds 3.000 ± 2.645 particles/L; and in the mixed-water ponds, where the water from the river and the sea were mixed, 0.666 ± 0.577 particles/L. The average MPs concentration in the sediment of Citarum River was 16.666 ± 0.577 particles/100 g; in the seawater ponds 13.335 ± 1.527 particles/100 g; in the mixed-water ponds 11.665 ± 0.577 particles/100 g; and in the seawater 3.335 ± 0.331 particles/100 g. The average of MPs concentration in the gut and gills of milkfish in the seawater ponds was 2.666 ± 2.333 particles/fish, and in the mixed-water ponds was 1.166 ± 0.983 particles/fish. The average of MPs concentration in the milkfish tissues taken from the sea was 1.333 ± 0.577 particles/fish; and for the ones taken from the mixed-water ponds, the concentration was 1.111 ± 0.838 particles/fish. Using the Kruskal Wallis test to generate statistical analysis, there is a significant difference between the MPs concentrations in the water and sediment samples of Citarum River based on their locations (p value = 0.024 and 0.032 < 0.05). The most dominant plastic polymers in the samples were polyethylene (PE) and polypropylene (PP). There is no correlation between the level of MPs concentrations in water and sediments and the level of MPs concentrations in milkfish. However, the existence of microplastics in every sample that came from different points in the sampling area should sound an alarm, either to the local government or residents.

The invasive marine macroalga Chaetomorpha valida blooms frequently in Apostichopus japonicus culture ponds in North China, resulting in negative environmental consequences. The factors driving this algal overgrowth are unclear. Previous studies observed that eutrophication strongly influences abnormal growth of nuisance macrophytes, but relatively few studies have addressed the types and abundance of nitrogen in A. japonicus culture ponds during the seasonal progression of a C. valida bloom and the effects of nitrogen source and N/P on C. valida growth and photosynthesis. In this study, we describe the structural features of nitrogen abundance and the seasonal progression of a C. valida bloom and uncover a relationship between nitrogen enrichment and C. valida growth. Common garden experiments demonstrated that C. valida can utilize different forms of nitrogen in the environment for rapid growth. Growth rate and photosynthesis capacity were related to the nitrogen source and N/P ratio. This study will provide a reference for maintenance of ecological balance and healthy aquaculture in A. japonicus culture ponds.

We aimed to develop a sustainable adsorbent for bisphenol A (BPA), an endocrine disruptor that seriously threatens human health. First, microcrystalline cellulose (MCC) was reacted with 2-bromoisobutyrylbromide to obtain a surface initiator (SI) for the grafting of polystyrene (PS), poly(lauryl methacrylate) (PLMA), and poly(N,N-dimethylaminoethyl methacrylate) (PDM) through ARGET-ATRP. These polymers may have favorably interacted with BPA, which led to its removal. SIs were characterized by FTIR and XPS to corroborate the grafting of 2-bromoisobutyryl and determine its abundance. X-ray diffraction analysis indicated retained crystal morphology with decreased MCC crystallinity. FTIR, thermogravimetric, and elemental analyses confirmed the grafting of MCC with polymers and revealed their composition. PS and PLMA had a minor effect on the crystallinity and morphology of MCC microfibers, whereas grafting PDM decreased the crystallinity of cellulose and the particle size. MCC grafted with polymers were tested as adsorbents of BPA by measuring the equilibrium uptake and removal through column filtration. PDM was found to endow cellulose with superior capacity of removing BPA, which was enhanced with increased amount of grafted polymer. A comparison of MCC grafted with PDM with activated carbon as adsorbents of BPA suggested the superior performance of the developed materials based on the largest maximum uptake.

Scale-up and commercialization of biodiesel is often delimited by costly feedstock that adds up to the process costs. These underlying issues demand the exploration of unconventional cheap feed to improve the process economics. Conversion of waste cooking oil (WCO) into biodiesel could reduce the process costs by 60–70%. However, the continuous exposure to heat during frying leads to oxidation as well increase in the free fatty acid (FFA) content which intensifies the time and energy required for transesterification. The present study analyzes the effect of parameters over the conversion of WCO (with 8.17% FFA) into biodiesel via two-step acid-alkali-based microwave-assisted transesterification. Response surface methodology (RSM) was used to optimize the oil:methanol volume ratio, microwave power, and reaction time during the acid-catalyzed esterification to bring down the FFA below 1%. Microwave irradiation of 250 W, with methanol:oil molar ratio of 19.57:1 [oil:methanol volume ratio of 1.31 (expressed as decimal)] and reaction time of 35 s, resulted in 0.082% of FFA. Alkali-catalyzed transesterification with methanol:oil molar ratio of 5:1 with 2% sodium hydroxide at 65 °C thereby produced fatty acid methyl esters (FAMEs) with the volumetric biodiesel yield of 94.6% in 30 min. Physiochemical properties of the transesterified WCO were well comparable with the biodiesel standards. The study highlights the essentiality of multivariate optimization for the esterification process that could aid in understanding the interactive effects of variables over FFA content. Such studies would benefit in scaling up of the transesterification process at industrial level by improving the economics of the overall bioprocess.

Fertilization with animal manure is one of the main routes responsible for the introduction of antibiotic residues, antibiotic resistance genes, and zoonotic bacteria into the environment. The aim of this study was to assess the effect of the use of pig (swine) manure as a fertilizer on the presence and fate of six antibiotic residues, nine antibiotic resistance genes, and bacteria (zoonotic bacteria Salmonella spp. and Campylobacter spp. and E. coli as indicator for Gram-negative bacterial species of the microbiota of livestock) on five fields. To the best of our knowledge, the present study is the first to assess a multitude of antibiotic residues and resistance to several classes of antibiotics in pig manure and in fertilized soil over time in a region with an intensive pig industry (Flanders, Belgium). The fields were sampled at five consecutive time points, starting before fertilization up to harvest. Low concentrations of antibiotic residues could be observed in the soils until harvest. The antibiotic resistance genes studied were already present at background levels in the soil environment prior to fertilization, but after fertilization with pig manure, an increase in relative abundance was observed for most of them, followed by a decline back to background levels by harvest-time on all of the fields studied. No apparent differences regarding the presence of antibiotic resistance genes in soils were observed between those fertilized with manure that either contained antibiotic residues or not. With regard to dissemination of resistance, the results presented in this study confirm that fertilization with animal manure directly adds resistance genes to the soil. In addition, it shows that this direct mechanism may be more important than possible selective pressure in soil-dwelling bacteria exerted by antibiotic residues present in the manure. These results also indicate that zoonotic bacteria detected in the manure could be detected in the soil environment directly after fertilization, but not after 1 month. In conclusion, although some antibiotic residues may be present in both manure and soil at concentrations to exert selective pressure, it seems that antibiotic resistance is mostly introduced directly to soil through fertilization with animal manure.

The Moravian-Silesian region of the Czech Republic with its capital city Ostrava is a European air pollution hot spot for airborne particulate matter (PM). Therefore, the spatiotemporal variability assessment of source contributions to aerosol particles is essential for the successful abatement strategies implementation. Positive Matrix Factorization (PMF) was applied to highly-time resolved PM₀.₁₅–₁.₁₅ chemical composition (1 h resolution) and particle number size distribution (PNSD, 14 nm – 10 μm) data measured at the suburban (Ostrava-Plesná) and urban (Ostrava-Radvanice) residential receptor sites in parallel during an intensive winter campaign. Diel patterns, meteorological variables, inorganic and organic markers, and associations between the chemical composition factors and PNSD factors were used to identify the pollution sources and their origins (local, urban agglomeration and regional). The source apportionment analysis resolved six and four PM₀.₁₅–₁.₁₅ sources in Plesná and Radvanice, respectively. In Plesná, local residential combustion sources (coal and biomass combustion) followed by regional combustion sources (residential heating, metallurgical industry) were the main contributors to PM₀.₁₅–₁.₁₅. In Radvanice, local residential combustion and the metallurgical industry were the most important PM₀.₁₅–₁.₁₅ sources. Aitken and accumulation mode particles emitted by local residential combustion sources along with common urban sources (residential heating, industry and traffic) were the main contributors to the particle number concentration (PNC) in Plesná. Additionally, accumulation mode particles from local residential combustion sources and regional pollution dominated the particle volume concentration (PVC). In Radvanice, local industrial sources were the major contributors to PNC and local coal combustion was the main contributor to PVC. The source apportionment results from the complementary datasets elucidated the relevance of highly time-resolved parallel measurements at both receptor sites given the specific meteorological conditions produced by the regional orography. These results are in agreement with our previous studies conducted at this site. Graphical abstract