Exchangeable versus residual metals in naturally aged plastic litter.

Metals may be associated with plastics as additives arising from manufacture or through acquisition from the environment, but these associations are often poorly defined or referred to synonymously when considering metal availability. In this study, samples of plastic litter (n = 22) have been collected from various environmental and industrial compartments of Lublin Province, Poland, and fractionated according to polymer type (polyethylene, polyethylene terephthalate, nylon, expanded polystyrene, polypropylene, and "mixed") before being micronised to < 2 mm. Composites (n = 89) were subjected to two phases of a standardised and widely employed sequential extraction protocol (Bureau Communautaire de Reference; BCR) in order to define available (acid-soluble and exchangeable) and residual (soluble in boiling aqua regia) concentrations of Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn. For a given metal, total content, calculated by summing available and residual components, was highly variable, both between locations and amongst polymer categories, reflecting the heterogeneous distribution of a multitude of different additives. Overall, however, concentrations were greatest for Fe, with medians of several hundred to several thousand mg kg-1 amongst the different polymers, and lowest for Cd, Co, and Ni, where nearly all concentrations were below 10 mg kg-1. Median percentage metal availabilities were greatest for expanded polystyrene and were above 25% for Mn and Zn and below 10% for Cr and Fe in all polymer types. These observations are largely, but not entirely, attributed to the relative contributions of metals acquired from the environment and metals present as additives and residues. Significantly, the approach employed allows direct comparisons of metal availability in plastics with metal availability in environmental solids in order to evaluate the overall impacts of plastics in metal risk assessments.

The high dose of biochar reduces polycyclic aromatic hydrocarbons losses during co-composting of sewage sludge and wheat straw.

The aim of the study was to investigate the effect of the biochar (BC) dose on solvent extractable (Ctot) and freely dissolved (Cfree) polycyclic aromatic hydrocarbons (PAHs) content during co-composting. A significantly better reduction of Σ16 Ctot PAHs after 98 days occurred during composting with BC (for 1% of BC - 44% and for 5% of BC - 23%) than in the control (15%). Despite the relatively high reduction of Ctot PAHs in the experiment with 5% BC rate, the content of the PAHs was still the highest compared to other variants. Regarding Cfree PAHs, 5% rate of BC resulted in the best reduction of PAHs, while the 1% BC dose resulted in a lower reduction of Cfree than the control. For 1% BC, PAHs losses was more effective, and sequestration processes played a less significant role than in the experiment with 5% dose of BC. The total and dissolved organic carbon, and ash were predominantly responsible for Ctot and Cfree losses, and additionally pH for Cfree. The results of the experiment indicate that BC performs a crucial role in composting, affecting the Ctot and Cfree PAHs in the compost but the final effect strictly depends on the BC dose.

Plant-Waste-Derived Sorbents for Nitazoxanide Adsorption.

The increased application of drugs during the COVID-19 pandemic has resulted in their increased concentration in wastewater. Conventional wastewater treatment plants do not remove such pollutants effectively. Adsorption is a cheap, effective, and environmentally friendly method that can accomplish this. On the other hand, maintaining organic waste is required. Thus, in this study, plant waste-derived pelletized biochar obtained from different feedstock and pyrolyzed at 600 °C was applied for the adsorption of nitazoxanide, an antiparasitic drug used for the treatment of SARS-CoV-2. The adsorption was fast and enables one to remove the drug in one hour. The highest adsorption capacity was noted for biochar obtained from biogas production (14 mg/g). The process of NTZ adsorption was governed by chemisorption (k2 = 0.2371 g/mg min). The presence of inorganic ions had a detrimental effect on adsorption (Cl-, NO3- in 20-30%) and carbonates were the most effective in hindering the process (60%). The environmentally relevant concentration of DOM (10 mg/L) did not affect the process. The model studies were supported by the results with a real wastewater effluent (15% reduction). Depending on the applied feedstock, various models described nitazoxanide adsorption onto tested biochars. In summary, the application of carbonaceous adsorbents in the pelletized form is effective in nitazoxanide adsorption.

The life cycle study revealed distinct impact of foliar-applied nano-Cu on antioxidant traits of barley grain comparing with conventional agents.

Despite that the applicability of Cu-based engineered nanoparticles (ENPs) as an antibacterial and antifungal agent for plant protection has been studied widely, little is known about their role in the improvement of crop yield and quality. Here, a full life study was performed to investigate the nutritional quality and bioactivity of barley grains under foliar application of nano-/microparticulate (nano-Cu, nano-CuO, micro-Cu) and ionic Cu compounds (CuSO4, CuEDTA). Hordeum vulgaris L. plants were sprayed with Cu compounds at 500 mg/L during the end of tillering and the beginning of heading. Yield, mineral composition, protein and dietary content, antioxidant (phenolic, anthocyanin, flavonoid, tannin, flavanol) content and antioxidant capacity of barley grain were evaluated. Grain yield was unaffected by all treatments. Only nano-Cu and ionic compounds enhanced Cu accumulation in grain: 2-fold increase was observed compared to the control (2.6 µg/kg). Nano-Cu also increased the dietary fiber content by 19.9 %, while no impact of the other treatments was determined. The content of phenolic compounds, the main group of antioxidants, remained unchanged after Cu supply. In general, for all Cu treatment, antiradical and reducing abilities were decreased or were at the similar level in relation to the control. On the other hand, chelating power in grain extracts was 2-4 times higher under nano-Cu/nano-CuO/micro-Cu than in the untreated sample, while the ionic compounds had no impact on the chelating indicator. Our results demonstrated that more favorable effects were triggered by nano-Cu than CuSO4 or CuEDTA on the tested indicators of barley grain, despite that both compounds resulted in similar superior Cu acquisition. It suggests that nano-Cu may be considered as an alternative agent to be used as economic and traditional fertilizers.

Physicochemical Characteristics of Biochar from Waste Cricket Chitin (Acheta domesticus).

The properties of biochar (BC) from crustacean chitin are relatively well understood, while there are few studies on BC from insect chitin. This study presents the characterization and phytotoxic assessment of BC produced from crickets and cricket chitin. Cricket powder (BCCR) and cricket chitin (BCCH) were pyrolyzed at 500 °C and 700 °C. Physicochemical characteristics, N ad-/desorption, FTIR, were examined. SEM images were also performed. Regardless of the pyrolysis temperature, biochars were characterized by a densely "packed" solid surface/monolithic type with a non-porous structure (0.05-0.22 m2/g) and high content of N (9.4-11.8%). BCCHs showed a higher pH (12.2-12.4) compared to BCCR (8.7-10.8). Based on the XRD analysis, BCs were characterized by an amorphous carbon turbostratic structure and a randomly oriented graphitic-like micro-crystallite structure. FTIR spectra of BCs confirmed the presence of various O2 and N-functional groups on the BC surface. BCCHs added to soil at rates from 0.5 to 1.5% significantly reduced the germination of Lepidium sativum. Stimulation of root elongation was also observed in the case of BCCR500 1.0% and BCCR700 1.5%. Thermal degradation of cricket powder and cricket chitin promotes the formation of organic N-containing heterocyclic rings, which lead to the production of N-doped carbons with potential uses in energy storage and the contaminations sorption.

Biochars ages differently depending on the feedstock used for their production: Willow- versus sewage sludge-derived biochars.

The aim of this study was to determine the effect of abiotic aging of biochars under controlled laboratory conditions on its physicochemical properties and in consequence on their stability. Biochars (BCs) produced at 500 and 700 °C from willow or sewage sludge were incubated at different temperatures (-20, 4, 20, 60, or 90 °C) for 6 and 12 months. Pristine (i.e. immediately after their production) and aged BCs were characterized using a range of complementary methods. As a result of simulated temperature aging, there was a change in all biochar properties studied, with the direction of these changes being determined by both the type of feedstock and biochar production temperature. At all temperatures, aging was the most intense during the first 6 months and led to oxidation of the biochars and removal of the most labile components from them. The intensity of these processes increased with increasing aging temperature. Incubation of the biochars for another 6 months did not have such a significant effect on the biochar properties as that observed during the first months of incubation, which is evidence that the biochars had reached stability. The sewage sludge-derived biochars with a higher mineral content than the willow-derived biochars were less stable. The low-temperature biochars (BC-500) with lower aromaticity were more prone to abiotic oxidation than the high-temperature biochars (BC-700) with higher aromaticity and structurally ordered C. Based on this study, it can be concluded that aging induced changes will be specific for each biochar, i.e. they will depend on both the type of feedstock and pyrolysis temperature. Nonetheless, all biochars will be oxidized to a smaller or greater extent, which will result in an increase in the number of surface oxygen functional groups, an increased degree of their hydrophilicity and polarity, and a decrease in pH.

Co-application of sewage sludge with biochar increases disappearance of polycyclic aromatic hydrocarbons from fertilized soil in long term field experiment.

The application of sewage sludge with biochar as fertilizer may be a new method improves soil properties. Biochar increases of the crops productivity and reduction of bioavailability of contaminants. In the present study the persistence of sum of 16 (Σ16) PAHs (US EPA 16 PAHs) in a sewage sludge-amended soil (11t/h) and in a sewage sludge-amended soil with the addition of biochar (at a rate of 2.5, 5 or 10% of sewage sludge (dry weight basis)) was determined. This study was carried out as a plot experiment over a period of 18months. Samples for analysis were taken at the beginning of the study and after 6, 12 and 18months from the beginning of the experiment. Application of sewage sludge as a soil amendment did not cause a significant change (P≥0.05) in the soil content of Σ16 PAHs. In turn, the addition of biochar with sewage sludge to the soil, regardless of the contribution of biochar in the sewage sludge, resulted in a significant decrease in PAH content already at the beginning of the experiment. Throughout the experiment, in all treatments the PAH content varied, predominantly showing a decreasing trend. Ultimately, after 18months the content of Σ16 PAHs decreased by 19% in the experiment with sewage sludge alone and by 45, 35 and 28% in the experiment with sewage sludge and the 2.5%, 5.0% and 10% biochar rates, respectively. After 18months of the study, the largest losses in the sewage sludge-amended soil were observed for 2- and 3-ring PAHs. In the sewage sludge- and biochar-amended soil, compared to the beginning of the study and the sewage sludge-amended soil, the highest losses were found for 5- and 6-ring PAHs (2.5 and 5.0% rates) as well as for 5- and 2-ring PAHs (10% rate).

Winter wheat fertilized with biogas residue and mining waste: yielding and the quality of grain.

BACKGROUND: Environmental protection problems and efforts to increase agricultural productivity result in attempts to use various organic and mineral wastes as fertilizers. This study aimed to determine the effect of biogas residue (BR) and mining waste (MS) fertilization on wheat yield as well as the nutritional and pro-health quality of grains produced. RESULTS: After the application of MS and BR wheat grain yield was increased compared to unfertilized wheat. The highest grain yield and thousand-grain weight were obtained after MS+BR fertilization. Grains of wheat fertilized with BR and MS+BR contained significantly more protein and wet gluten compared to no fertilization and conventional fertilization (NPK). The studied conditions did not statistically affect starch content. BR fertilization significantly increased the total phenolic content; however, grains of wheat fertilized with NPK were characterized by the highest content of flavonoids and syringic, p-coumaric and sinapic acids. Compared to NPK, waste fertilizations positively affect the reducing power and antiradical activity of wheat. CONCLUSION: These results suggest that the wastes evaluated can be an alternative to conventional fertilization in the soil tested that without any significant deterioration and in some cases significant improvement of yield and wheat quality. © 2015 Society of Chemical Industry.

Ecotoxicological assessment of residues from different biogas production plants used as fertilizer for soil.

Residues from biogas production (RBP) are a relatively new materials, which may be an interesting resource for the improvement of soil fertility. Nevertheless, in spite of the potential benefits from the agricultural utilization of RBP, there is a need of comprehensive estimation of their toxicity. This information is needed to exclude potential negative environmental impacts arising from the use of RBP. Samples of RBP obtained from six biogas production plants with varied biogas production methods were analysed. The samples with and without separation on solid and liquid phases were investigated. The physicochemical properties of the RBP, heavy metals content (Cr, Cu, Ni, Cd, Pb i Zn) and toxicity on bacteria (Vibrio fischeri, MARA test - 11 different strains), collembolans (Folsomia candida) and two plant species (Lepidium sativum and Sinapis alba) was investigated. Toxicity of RBP was examined using Phytotoxkit F (root growth inhibition), collembolan test (mortality, inhibition of reproduction), Microtox® (inhibition of the luminescence of V. fischeri) and MARA test (growth of microorganisms). An especially negative effect on the tested organisms whereas was noted for the liquid phase after separation. In many cases, RBP without separation also showed unfavourable effects on the tested organisms. Liquid phase after separation and non-separated materials caused inhibition of root growth of L. sativum and S. alba at the level of 17.42-100% and 30.5-100%, respectively, as well as the inhibition of reproduction of F. candida with the range from 68.89 to 100%. In most cases, no ecotoxicological effect was observed for solid phase after separation for tested organisms. The solid phase after separation presented the most favorable properties between all investigated RBP. Therefore, it can be a potential material for the improvement of soil properties and for later use in agriculture.

An ecotoxicological evaluation of soil fertilized with biogas residues or mining waste.

This paper presents an ecotoxicological evaluation of soil fertilized with biogas digestate (BD) or mining waste (MS). The study was performed under pot experiment conditions. BD was added at a dose of 1.5 and 3% to the soil. MS was applied at a dose of 10 and 20%. Samples were collected at the beginning of the experiment and after 180 and 360 days from the start of the study. In addition, a parallel experiment with the addition of CaO was done. This was designed to eliminate the adverse effect of low soil pH on the test organisms. A battery of ecotoxicological tests was used based on tests with plants (Phytotoxkit F), microorganisms (Microtox), and crustaceans (Daphtoxkit F). In most cases, the obtained results showed that the investigated wastes had a stimulating effect on the growth of Lepidium sativum roots. The highest content of BD was an exception since it inhibited the growth of L. sativum roots. After adding BD and MS, both the luminescence of Vibrio fischeri and the mortality of Daphnia magna was at a similar level to that in the control soil. An exception was the significant increase in the mortality of D. magna after 48 h for soil with 3% BD. The tests performed after 6 and 12 months showed that, with time, the toxicity of the waste-amended soil fluctuated, but ultimately decreased in most cases compared to the control. The effect of the addition of CaO on the examined toxicity parameters was different and depended on the experimental variant.

Wheat Bread with Pumpkin (Cucurbita maxima L.) Pulpas a Functional Food Product.

In this study, a new application of pumpkin pulp in bread production is shown. The aim of this work is to determine the influence of the addition of fresh pumpkin pulp directly into wheat flour on physical, sensorial and biological properties of bread. The bioaccessibility of active compounds was also studied. An increase in the addition of pumpkin pulp from 5 to 20% (converted to dry matter) caused a decrease of bread volume and increase of crumb hardness and cohesiveness. The sensory characteristics of the bread showed that a partial replacement of wheat flour with up to 10% of pumpkin pulp gave satisfactory results. The taste, aroma and overall acceptability of control bread and bread containing 5 or 10% of pulp had the highest degree of liking. The addition of higher levels of pumpkin pulp caused an unpleasant aroma and taste. Pumpkin pulp is a good material to complement the bread with potentially bioaccessible phenolics (including flavonoids) and, especially, with peptides. The highest antioxidant activity was observed, in most cases, of the samples with added 10 and 15% of pumpkin pulp. The addition of the pulp significantly enriched the bread with potentially bioaccessible angiotensin-converting enzyme (ACE) inhibitors. The highest activity was determined in the bread with 15 and 20% pumpkin pulp. ACE inhibitors from the tested bread were highly bioaccessible in vitro. Pumpkin pulp seems to be a valuable source of active compounds to complement the wheat bread. Adding the pulp directly to the wheat flour gives satisfactory baking results and reduces the cost of production. Additionally, pumpkin pulp is sometimes treated as waste material after the acquisition of seeds, thus using it as bread supplement also has environmental and economic benefits. Key words: pumpkin, bread, texture, antioxidants, bioaccessibility in vitro, angiotensin-converting enzyme (ACE) inhibition.