Search

Organic agriculture (OA) is a continuously growing global concept that emphasizes the use of sustainable and environmentally-friendly practices. By adopting OA, it is possible to improve ecosystems services, increase biodiversity, decrease environmental pollution, reduce carbon footprints and mitigate greenhouse gas emissions, generating food that is free from harmful residues of agrochemicals, thereby enhancing food safety and security. This study provides a comprehensive review of the latest insights on the global utilization of land resources in OA, focusing particularly on some EU countries that experienced a notable and rapid progress in organic farming during the past two decades. With negligible 1.6% (75 Mha) of global cropland is currently dedicated to OA, there is ample opportunity to expand the adoption of OA and realize its multi-beneficial potential for farmers (by premium prices), and consumers (by healthier and nutritious food). The importance of OA has been recognized by the most recent EU agro- environmental policies and green strategies, with an ambitious goal to have at least 25% of agroecosystems under organic management by 2030. Despite numerous financial supports and a multifold increase in OA land area, many member states are unlikely to achieve this goal, including Croatia, which currently has a share of only 8% (~109, 000 ha) of lands in OA. Furthermore, converting conventional land to organic farming has not always led to an increase in value-added final OA products. EU policies related to OA have been focused on the area of land cultivated organically, rather than overall production performance, and financial subsidies have been essential to achieve this policy. Therefore, some of critical obstacles and challenges for OA under rising pressures due to global climate change, public health and geopolitical crises need to be managed by specifically designed policies and regulations, which would contribute to more sustainable OA, i.e., food safety and security.

Metal contaminated soils (MCS) pose a serious constraint to food production and human and environmental health. A controlled pot experiment was conducted with the different biochar types (derived from municipal sewage sludge – SL, wood chips – WC, and horse manure - HM) and their rates (1% and 4% w/w) to examine: i) release of metals from the MCS matrix (collected near a former Pb-Zn mine and Pb smelter plant near Zerjav, Slovenia) and ii) their chemical speciation in the water leachate 175 days after the incubation period. The highest Cd (0.07 mg/L) and Zn (0.95 mg/L) concentrations in percolates, followed by the lowest pH (6.52) were found in Control treatment (MSC without biochar addition). In addition, the highest Cu (0.17 mg/L) and Pb (0.45 mg/L), but the lowest Cd (0.04 mg/L) and Zn (0.63 mg/L) concentrations, followed by the highest pH (6.72), were found in WC treatment with 4%. Chemical speciation calculations performed in Visual Minteq software using the NICA-Donnan model indicated that Cu and Pb were present in all percolates as organo-complexes with dissolved organic carbon fractions. However, within the chemical pool of Cd and Zn, their free cationic forms (Cd2+, Zn2+) and chloro-complexes were confirmed in addition to organo complexes. Obtained results suggest that the amelioration of MCS with a particular biochar type could affect the transfer of metals from a contaminated matrix to waters.

Metal contaminated soils (MCS) are raising global issue which threats human and environmental health and safety. A controlled pot study was performed to investigate the effect of two different wood- derived bioash types (fly - FA and bottom – BA from cogeneration biomass plant) at 1% and 4% w/w rates on: i) release of metals from the MCS matrix (collected near a former mine and metallurgical plant in the town of Zerjav, Slovenia) and ii) their chemical speciation in the water leachate 175 days after the incubation period. The highest pH reaction (7.13), electrical conductivity (EC 27.3 dS/m), Pb (1.40 mg/L), Cd (0.96 mg/L) and Cu (0.18 mg/L) concentration in water percolates were detected in FA 4% treatment. In addition, the lowest pH reaction (6.52) followed by the highest Zn concentration (0.95 mg/L) were found in the water percolates from the Control (MCS without bioash addition) treatment. Chemical speciation modeling performed in Visual Minteq software using the NICA-Donnan approach indicated that all examined metals (Cd, Cu, Pb and Zn) were dominated in all water leachates (including the MSC control without bioash treatment) exclusively as organo- complexes, oscillating among humate and fulvate pools. The most toxic free metallic forms (of Cd and Zn) and chloro-complexes (of Cd) were present in negligible portions (

Biomass-fuelled facilities generate alkaline and mineral-/nutrient-enriched co-product (ash) that has to be appropriately managed, and preferably reused. The assumption that wood biomass fly ash (BFA) could be used in chemical amelioration of soil acidity and fertility was tested by: i) physicochemical charac terisation of BFA and ii) bioassay with maize grown in acidic (pHKCl 4.68) hydromorphic soil amended with BFA (0e10% w/w). Scanning electron microscopy with energy dispersive X-ray spectroscopy and X ray diffraction revealed non- homogeneous (ir)regular spherical/porous agglomerated particle morphology and distinctive distribution of Si-/Ca-/K-based minerals, while secondary ion mass spec trometry, for the first time, confirmed their isotopic (six Ca, three Si/Mg and two K isotopes) diversity. BFA addition strongly shifted soil pHKCl (up to 9.1), raised salinity (by > 8.2-fold) and the content of most phytonutrients (up to 5.4-fold) ; however, BFA amendments at >1.25% restricted the maize root and shoot growth, likely due to alkaline stress as indicated by necrotic/chlorotic symptoms at >5.0% rate. The BFA amendments increased total concentration of metals in soil (without exceeding the levels recognised as contamination) ; however, phytoextraction of Cd, Zn, Mn, Cu and Mo was significantly supressed (Cd by almost 12-fold), confirming that BFA improved soil-plant metal immobilisation, shifting rhizosphere biogeochemistry towards chemisorption/precipitation reactions. Even though results revealed a strong liming and PeKeCaeMgeZneMneCu enrichment potential of BFA, to avoid possible negative envi ronmental implications (saline/alkaline stress, metal contamination, adverse effects on soil microbiome), quantitative and qualitative ex ante evaluation of the BFA/soil matrix combinations is essential before application to ameliorate suboptimal (acidic, low-nutrient) or metal-contaminated soils

Agriculture in Neretva River estuary (Republic of Croatia) is an important economic activity for more than 30, 000 people. Due to proximity to Adriatic Sea and porous (karst) hydrogeological structure of alluvial river valley, sea water intrusion is common. As a consequence, most water sources used for irrigation are saline (EC>2 dS m-1) periodically or even continuously, which can have enormous effects on soil physical and chemical properties as well as on viability of ecosystems in the estuary. Salinisation of the soil that surrounds roots (rhizosphere) diminishes growth and development of most crops, impairing yield and quality. Moreover, increased soil salinity may enhance uptake and accumulation of certain biotoxic elements (e.g. Cd) in edible crop parts and thus in the human food chain. In this study, chemical analyses of water (open channels and groundwater) and topsoil saturation extracts indicated potential secondary salinisation processes on around 2, 500 ha of irrigated land in Neretva River estuary, with EC and SAR values exceeding those recommended for agriculture by FAO. However, intensive rainfall (>650 mm) during winter and homogenous and stable solum structure with favourable water permeability properties enable salt leaching and underpin resilience of agricultural ecosystems. Nevertheless, it is of utmost importance to control water and land salinisation processes in Neretva River valley to ensure sustainable agricultural production in the future.

Soil degradation under excessive salinity and pollution by potentially toxic metals are increasing rapidly in agricultural areas, representing a serious threat to food production and human food security. A factorial combination of four salt concentrations (0, 20, 40 and 60 mM NaCl) and three cadmium (Cd) levels (0.3, 2.5 and 5 mg kg-1) in peat soil on mineral uptake/distribution in radish plants (Raphanus sativus L. var. sativus) was studied under the greenhouse conditions. After 34 days of exposure to increasing NaCl concentrations, plants proportionally increased Na and Cl accumulation in leaf and hypocotyl tissues. Salinity significantly increased accumulation of Cd (up to 20%), Cu (up to 11%) and Zn (up to 7%) in leaves. In contrast, raising salinity levels did not affect Cd and Cu translocation from leaves and deposition into the edible hypocotyls, which may indicate that the phloem mobility of those elements in radish plants is relatively poor and unaffected by NaCl exposure. Increasing salinity improved Zn accumulation in the hypocotyl tissue up to 27%. Soil contamination by Cd resulted in 10-fold increases of Cd content in leaf and hypocotyl tissues, and significant decreases of Zn and Cu content in leaves. Cu and Zn deposition in radish hypocotyls was unaffected under saline conditions. Leaf accumulation of all observed metals (Na, Cd, Zn and Cu) exceeded their accumulation in edible tissues, suggesting that the apoplast and the vacuoles of leaf cells may be the sites of preferential deposition of these metals.

Human-induced salinization and trace element contamination are widespread and increasing rapidly, but their interactions and environmental consequences are poorly understood. Phytoaccumulation, as the crucial entry pathway for biotoxic Cd into the human foodstuffs, correlates positively with rhizosphere salinity. Hypothesising that organic matter decreases the bioavailable Cd2+ pool and therefore restricts its phytoextraction, we assessed the effects of four salinity levels (0, 20, 40 and 60 mM NaCl) and three Cd levels (0.3, 5.5 and 10.4 mg kg− 1) in peat soil on mineral accumulation/distribution as well as vegetative growth and fruit yield parameters of muskmelon (Cucumis melo L.) in a greenhouse. Salt stress reduced shoot biomass and fruit production, accompanied by increased Na and Cl and decreased K concentration in above-ground tissues. A 25- and 50-day exposure to salinity increased Cd accumulation in leaves up to 87% and 46%, respectively. Accumulation of Cd in the fruits was up to 43 times lower than in leaves and remained unaltered by salinity. Soil contamination by Cd enhanced its accumulation in muskmelon tissues by an order of magnitude compared with non-contaminated control. In the drainage solution, concentrations of Na and Cl slightly exceeded those in the irrigation solution, whereas Cd concentration in drainage solution was lower by 2–3 orders of magnitude than the total amount added. Chemical speciation and distribution modelling (NICA-Donnan) using Visual MINTEQ showed predominance of dissolved organic ligands in Cd chemisorption and complexation in all treatments; however, an increase in salt addition caused a decrease in organic Cd complexes from 99 to 71%, with free Cd2+ increasing up to 6% and Cd-chlorocomplexes up to 23%. This work highlights the importance of soil organic reactive surfaces in reducing trace element bioavailability and phytoaccumulation. Chloride salinity increased Cd accumulation in leaves but not in fruit peel and pulp.

A greenhouse experiment was carried out to investigate the response of muskmelon (Cucumis melo L.) grown in peat at increasing root zone salinity and contamination of growing media with Cd. The effect of a factorial combination of four NaCl salinity levels (2 as control, 4, 6, and 8 dS m-1) and three levels of Cd in peat (0.3 as control, 5 and 10 mg kg-1) on mineral accumulation and distribution in plant as well as yield of muskmelon was assessed. Salt stress, indicated by reduced leaf dry matter content (4-34%) and marketable yield (up to 50%), was accompanied by significantly increased Na and Cl accumulation as well as decreased K concentration in leaves and fruits. Cadmium accumulation in leaves increased with increasing salinity 25 days after commencement of the salinity treatment ; however, after 50 days of salinity treatment, increased Cd accumulation in leaves occurred only at the highest salinity (8 dS m-1). Cadmium accumulation in muskmelon fruits was not influenced by salinity. The order of Cd concentrations in tissues [in mg kg-1: leaves (9.1-17) > peel (0.4-0.6) > pulp (0.3-0.4)] suggests that muskmelon has low capacity (i) to transport Cd into fruits, and/or (ii) to translocate Cd from leaves to fruits. The hypothesis that NaCl salinity enhances Cd uptake was not supported for muskmelon.

The Jegricka had been a natural stream which was partially regulated and included into the canal network Danube-Tisza-Danube Hydro System (Vojvodina, Serbia). The stream has a multifunctional character. It provides irrigation water and serves for land reclamation activities in the area through which it flows. The area includes farmland for the most part and several small villages. The stream itself and a zone along its banks have been recognized for special ecological significance and they were awarded the status of a protected natural resource. Sediments from the Jegricka stream have been analyzed in order to assess possible impact of various degradation processes on the environmental status of this protected natural resort. Concentrations of hazardous and harmful substances were determined in 20 sediment samples gathered at different points of the stream. The analyses involved eight trace elements (heavy metals and microelements) and sixteen PAH compounds. The obtained results indicated that the quality of sediments was mostly satisfactory, in spite of a relatively large exposure to point and non-point pollution sources (wastewaters from municipal and industrial sources, agriculture etc.). The contents of heavy metals in the sediments were found to be within the limits of tolerance (Pb 3.28-27.40 ; Cd 0.00-0.20 ; Cr 7.27-38.97 ; Ni 5.11-35.66 ; Cu 5.91-33.74 ; Zn 13.80-92.12 ; Co 1.60-11.94 mg kg-1). Also, the concentration of total PAHs was below the level considered as harmful to the environment. The concentrations of individual PAHs in the sediments were as a rule below 1 mg kg-1. The only exceptions were increased arsenic concentrations. Maximum arsenic concentrations determined for some locations, for example 79.37 and 69.73 mg kg-1, exceed several-folds the maximum permissible concentration. These excessive concentrations may have a negative impact on the environment in the stream itself and its surroundings.

The synthesis and application of nanoparticles have been actively studied in the modern era as it holds promises for effective and targeted strategies to deliver drugs inside the human body. Nanoparticles (NPs) play a big role in cancer diagnosis and have various advantages over other conventional chemotherapeutic drug delivery systems. But, the application of emerging engineered NPs to heavy toxic metals such as zinc, cobalt, and iron has resulted in a major source of toxicity. The toxicity of nanomaterials is majorly determined by their physical and chemical properties such as size, charge, and surface area. Also, the mechanism of nanotoxicity is majorly via the production of reactive oxygen species that create oxidative stress, thereby activating inflammatory cytokines and the mechanism of DNA damage that ultimately results in the cell death. So, mechanistic study needs to be done on nanomaterials to elucidate the mechanism involved in nanotoxicity and to generate less toxic and efficient nanomaterials.