Pristine chitosan beads were modified with sulfur (S)-containing functional groups to produce thiolated chitosan beads (ETB), thereby increasing S donor ligands and crosslinks. The effect of temperature, heating time, carbon disulfide (CS₂)/chitosan ratio, and pH on total S content of ETB was examined using Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The total S content of ETB increased with increasing CS₂/chitosan ratio and decreased with decreasing pH and increasing temperature (>60 °C) and heating time (at 60 °C). Spectroscopic analyses revealed the presence of thiol (–SH)/thione, disulfide (–S–S–), and sulfonate groups in ETB. The thiolation mechanism involves decomposition of dithiocarbamate groups, thereby forming thiourea crosslinks and trithiocarbonate, resulting in –SH oxidation to produce –S–S– crosslinks. The partially formed ETB crosslinks contribute to its acid stability and are thermodynamically feasible in adsorbing Cd and Cu. The S-containing functional groups added to chitinous wastes act as sorbents for metal remediation from acidic environments.

Aluminum is ingested through foods, water, air, and even drugs. Its intake is potentiated further through foods and tea prepared in aluminum utensils and Al salt added in the drinking water for removal of suspended impurities and also fluoride in the affected areas. The ameliorating role of a blue green alga Spirulina is well documented to various pollutants in the animal models. We, therefore, examined its protective role (230 mg/kg body weight) on the hematology of male Swiss albino mice treated with aluminum (sub-acute = 78.4 mg/kg body weight for 7 days, sub-chronic = 7.8 mg/kg body weight for 90 days) and aluminum fluoride (sub-acute = 103 mg/kg body weight, sub-chronic = 21 mg/kg body weight), along with their recovery after 90 days of sub-chronic exposure. This study revealed significant reduction in the values of RBC (5–18 %), Hb (15–17 %), PCV (8–14 %), and platelets (26–36 %), and increase in WBC (54–124 %) in the treated mice, particularly after sub-acute exposure. Aluminum fluoride was comparatively more toxic than aluminum. Further, Spirulina supplement not only alleviated toxicity of test chemicals in Swiss albino mice but also led to their better recovery after withdrawal.

Although the gradual accumulations of Cu in orchard soils due to the application of Cu-based fungicides have been widely reported, limited information is available about the retention characteristics of fungicide-derived Cu in soil, especially in various size soil aggregates. This study described the adsorption characteristics of Cu from commonly used fungicide, Bordeaux mixture (CuSO₄ + Ca(OH)₂), onto various aggregate fractions (2000–1000, 1000–500, 500–250, 250–106, and <106 μm) of orchard soil. The Cu(NO₃)₂ was selected as a comparison. Two different types of adsorption experiments were conducted as follows: variable pH and variable Cu concentration experiments. The adsorption processes of Bordeaux mixture and Cu(NO₃)₂ onto the studied soil samples followed well with the Freundlich isotherm, and the adsorption isotherms were the S shaped. The adsorption amounts of Cu from different Cu compounds differed, and Bordeaux mixture can result in more Cu retention in soil than Cu(NO₃)₂. The adsorption ability of different size soil aggregates varied, and it was mainly governed by soil properties. The findings of this study suggested that both the chemical compositions of Cu compounds and the soil physical structure should be taken into account when performing soil Cu retention experiments with fungicide-derived Cu.

Cadmium nanoparticles can represent a risk in both industrial and environmental settings, but there is little knowledge on the impacts of their inhalation, especially concerning longer-term exposures. In this study, mice were exposed to cadmium oxide (CdO) nanoparticles in whole body inhalation chambers for 4 to 72 h in acute and 1 to 13 weeks (24 h/day, 7 days/week) in chronic exposure to investigate the dynamics of nanoparticle uptake and effects. In the acute experiment, mice were exposed to 2.95 × 10⁶ particles/cm³ (31.7 μg CdO/m³). The same concentration and a lower one (1.18 × 10⁶ particles/cm³, 12.7 μg CdO/m³) were used for the chronic exposure. Transmission electron microscopy documented distribution of nanoparticles into all studied organs. Major portion of nanoparticles was retained in the lung, but longer exposure led to a greater relative redistribution into secondary organs, namely the kidney, and also the liver and spleen. Accumulation of Cd in the lung and liver occurred already after 24 h and in the brain, kidney, and spleen after 72 h of exposure, and a further increase of Cd levels was observed throughout the chronic exposure. There were significant differences in both Cd accumulation and effects between the two exposure doses. Lung weight in the higher exposure group increased up to 2-fold compared to the control. Histological analyses showed dose-dependent alterations in lung and liver morphology and damage to their tissue. Modulation of oxidative stress parameters including glutathione levels and increased lipid peroxidation occurred mainly after the greater chronic exposure. The results emphasize risk of longer-term inhalation of cadmium nanoparticles, since adverse effects occurring after shorter exposures gradually progressed with a longer exposure duration.

The uptake of two heavy metals (chromium and lead) in sediments in experimental mesocosms under exposure to different metal concentrations was evaluated by monitoring their concentrations over time both in seawater and in sediment. Two separate experiments under laboratory-controlled conditions were carried out for the two metals. Sediments were collected from a protected natural area characterized by low anthropic influence and were placed in mesocosms that were housed in aquaria each with seawater at a different metal concentration. At pre-established time intervals, seawater and sediment samples were collected from each mesocosm for chemical analyses. Quantification of chromium and lead concentration in seawater and sediment samples was carried out by atomic absorption spectrometer with graphite furnace. Low doses of chromium and lead (<1 mg L⁻¹) do not entail an uptake in sediments and waters. At doses ≥1 mg L⁻¹, evolution of concentrations over time shows significant differences between these two metals: (i) chromium absorption from seawater is twice faster than lead; (ii) lead accumulates in considerable amount in sediments. The different behaviour of the two investigated heavy metals could be ascribed to different interactions existing between metal ions and different components of sediment.

Children especially infants are particularly sensitive to contaminant exposure, they are exposed to toxic substances including heavy metals via multiple pathways, i.e. food, air, water, soil and childcare products. To date, determination of metal bioaccessibility in teethers and feeding teats is missing in the literature; therefore, it is vitally important to assess their metal bioaccessibility and characterise the risk for children. The aim of this study is to determine the migration levels of toxic elements in teethers and feeding teats of different brands as a measure of metal bioaccessibility and characterise the risk for children exposed to these products. The migration limits of several heavy metals (Al, As, Ba, Cd, Co, Cu, Cr, Mn, Ni, Pb, Se, Sr, Zn) in different brands of teethers and feeding teats were determined simultaneously using inductively coupled plasma optical emission spectroscopy (ICP-OES) adopting a protocol in the European standards for safety of toys. With the exception of Pb, the migration limits of all elements in all brands of teethers and feeding teats were below the specified limits. However, in the case of Pb, the migration was above the specified limits in all samples except one brand of feeding teats. Risk assessment expressed as hazard index (HI) was calculated for detected elements and all samples. Although HI was below 1.0 for all samples except one sample, the high Pb concentration would pose a considerable risk to children. Therefore, we recommend a more thorough research and risk characterisation taking into consideration the factors that affect HI values.

Phthalate acid esters are widely used as plasticizers to impart plastic flexibility in various industrial applications. In this study, the content of seven phthalates, dibutyl phthalate (DBP), benzyl butyl phthalate (BBP), di-(2-ethylhexyl) adipate (DEHA), di-2-ethylhexyl phthalate (DEHP), di-n-octyl phthalate (DNOP), di-isononyl phthalate (DINP), and di-isodecyl phthalate (DIDP) were determined in paper cups using gas chromatography–mass spectrometry (GC-MS). In addition, the potential migration of these seven phthalates from paper cups into various food stimulants under different conditions was evaluated. The levels of DBP, DEHA, DEHP, and DNOP were in the ranges of 0.07–3.14, 0.16–42.69, 0.45–58.56, and 0.3–2.4 mg/kg, respectively. Meanwhile, BBP, DINP, and DIDP were not detected in most of the tested samples. In the migration test, DEHA was released to 50 % ethanol and n-heptane in a time-dependent manner and the maximum migration levels were 65.62 ± 3.61 and 95.56 ± 19.76 μg/L, respectively. The release of other phthalates was very low or negligible. These results demonstrated that paper cups are not a significant source of phthalate exposure; however, DEHA could be released from paper cups into alcoholic beverages or oily liquid beverages in the human diet.

The contents of elements in the top soil (upper 5 cm) and deeper soil (5 to 10 cm) layers and in Salix polaris (leaves and stem) from the former Soviet mining town of Pyramiden and its close vicinity on the Svalbard archipelago were determined. The analyses covered major and trace elements, including heavy metals, in order to describe anthropogenic impacts related to the management of the mining town. Soil samples and plant tissues were analysed from 13 localities across and close to town vicinity. The plant ground cover of all sampling points was determined, and plant tissues (leaves and stem) were collected. Higher contents of Cd (3–11 mg kg⁻¹) and Mo (11–33 mg kg⁻¹) were detected in the soils. With relation to the world average concentration of metals in soils, the geo-accumulation indexes (Igₑₒ) and the level of pollution of the analysed soils were classified into seven pollution grades. The soils of the studied localities were usually unpolluted (grade 1) when analysed for metals, with the soil pollution grades 4–6 identified only for Cd and Mo (moderately to strongly polluted). In Salix polaris, excessive amounts of Fe (60–1520 mg kg⁻¹), Zn (80–1050 mg kg⁻¹), Cd (0.2-5.5 mg kg⁻¹) and Cr (0–3.6 mg kg⁻¹) were observed. The Igₑₒ of these elements, compared with values considered sufficient for plants, showed pollution grades from 2 to 6. The pollution load index (PLI) ranged between 0.49 and 1.01. Only one locality could be considered polluted having a PLI higher than 1. Plant/soil transfer factors (TF) for trace metals decreased in the following order: Zn > Cu > Cd > Mn > Ni > As > Mo > Pb > Co > Al > Cr > Fe. The principal contribution of this study consists in the assessment of the contamination of soils and plants by toxic heavy metals in an otherwise pristine environment of the Svalbard archipelago related to urban/industrial activities.

The aqueous photodegradation of fluopyram was investigated under UV light (λ ≥ 200 nm) and simulated sunlight irradiation (λ ≥ 290 nm). The effect of solution pH, fulvic acids (FA), nitrate (NO₃ ⁻), Fe (III) ions, and titanium dioxide (TiO₂) on direct photolysis of fluopyram was explored. The results showed that fluopyram photodegradation was faster in neutral solution than that in acidic and alkaline solutions. The presence of FA, NO₃ ⁻, Fe (III), and TiO₂ slightly affected the photodegradation of fluopyram under UV irradiation, whereas the photodegradation rates of fluopyram with 5 mg L⁻¹ Fe (III) and 500 mg L⁻¹ TiO₂ were about 7-fold and 13-fold faster than that without Fe (III) and TiO₂ under simulated sunlight irradiation, respectively. Three typical products for direct photolysis of fluopyram have been isolated and characterized by liquid chromatography tandem mass spectrometry. These products resulted from the intramolecular elimination of HCl, hydroxyl-substitution, and hydrogen extraction. Based on the identified transformation products and evolution profile, a plausible degradation pathway for the direct photolysis of fluopyram in aqueous solution was proposed. In addition, acute toxicity assays using the Vibrio fischeri bacteria test indicated that the transformation products were more toxic than the parent compound.