The effect of humic acid (HA), on the adsorption and transport of arsenic (As) onto and within a model iron oxide-based adsorbent, iron oxide-coated diatomite (IOCD), is investigated. Experimental results indicate that the adsorption of both As and HA is highly pH-dependent. As uptake was suppressed by HA, with the level of suppression increasing with HA concentration. The suppression is attributed to the partial coverage of the adsorption sites, as confirmed by elemental analysis. Adsorption energy analysis indicates that for As(III), the main interaction with IOCD is physical adsorption, whereas for As(V), it is more likely ion exchange. The presence of HA may alter the adsorption energy and interaction of As with the adsorbent, particularly at higher HA concentrations. Kinetic results indicate that HA did not affect the diffusional transport of As in systems with both As and HA. However, for IOCD preloaded with HA, the adsorption kinetics of As was significantly slower, although the As uptake was similar to the conditions of co-sorption with HA. The slower kinetics and similar equilibrium uptake of As in the HA-preloaded IOCD system may be attributed to the partial blockage of the intraparticular pores within IOCD, which slowed down the diffusion of As.

This work describes the experimental determination of the major degradation and sorption parameters of polycyclic aromatic hydrocarbons (PAHs) in a sensitive marine environment, the Northern Adriatic Sea (Mediterranean Sea). The persistence and sorption of complex PAH mixtures were analysed in the laboratory in conditions mimicking open-sea and coastal sediments, which differ in grain size and organic carbon content and are characterized by different oceanographic conditions including abiotic influences. The study investigated how sediment type and texture and salinity, temperature and solar irradiation conditions affect the partitioning of low molecular weight (LMW) and high molecular weight (HMW) PAHs into aqueous and solid phase, which critically influence their behaviour. With regard to the change from offshore to coastal conditions, HMW PAHs were found to be more sensitive to the increased salinity (from 21 to < 37 parts per thousand), whereas LMW PHAs were more sensitive to the temperature increase (from 11 to 22 °C). HMW PAHs were more affected by sediment type changes in terms of distribution coefficient (K d). Since the physicochemical properties of organic pollutants affect their distribution, transport, bioavailability and toxicity, analysing the accumulation and persistence of dissolved pollutants can provide useful information for environmental risk assessment and management.

Sewage sludge has been used as a fertilizer in agriculture, but human exposure to toxins due to crop exposure has been reported. This study evaluated the uptake of essential and nonessential elements from soil (exposed to sewage sludge) to roots, shoots, and grains of corn, aiming to estimate the daily intake corn consumption to assess the associated health risk. Corn plants were grown in soil amended with 0, 5, 10, and 20 tons of sewage sludge per hectare (t/ha). Soil, root, shoot, and grain samples were analyzed by inductively coupled plasma mass spectrometry. In soil, sludge application at 10 and 20 t/ha enhanced the Zn, Cu, Mo, Cd, Pb, Hg, and Ni concentration compared to control soil. Normally, corn plants exhibited essential and nonessential element concentrations significantly higher in roots than in grains and shoots. Selenium was equally distributed in roots, shoots, and grains but Mo was preferentially stored in grains. Cadmium, As, and Pb were more efficiently trapped in roots than other elements. Considering the estimated daily intake, for Brazilians, the concentrations were below the toxicological or the dietary reference values. In conclusion, chemical elements were efficiently trapped in roots and therefore applying 5 t/ha proportion of sewage sludge might be a sustainable and cost-effective strategy, with a very lower risk of toxicity due to consumption of grains. In contrast, sewage sludge at 20 t/ha enhanced element levels in plant parts and in places with higher corn consumption, estimated daily intakes are expected to rise.

Nikola Tesla B power plant (TENT-B), located on the Sava River in Obrenovac, 52 km west from the Serbian’s capital, Belgrade, is the second largest coal-fired power plant in the country, consisting of two blocks of 620 MW each. Samples of fresh coal ash obtained by coal combustion in TENT-B, as well as coal ash samples from the surface and 1-m depth of active, currently filled, and passive, previously filled and not currently used, cassettes, were taken from the coal ash dump. Ultrasonic extracts of the samples were analyzed using gas chromatography with mass selective detection (GC/MSD) in order to identify and quantify 16 priority polycyclic aromatic hydrocarbons (PAHs). Two PAH extraction mechanisms during coal ash dumping and storage processes are discussed and significant differences between them were established. PAH concentrations in the ash samples were compared statistically. Correlations between samples and sampling points were established, and leaching potential of samples was examined. Concentrations of PAHs can be reduced in coal ash sediments by environmental influences only after long time periods, and PAHs with two six-membered rings pose danger to underground waters, while PAHs with three rings pose danger to soil sediments.

Since the last century, humanity has sought ways to minimize the impact of the industrial growth in the environment. The textile industry, as one of the major contributors to water pollution, has been dumping coloured effluents which cause great impact in water bodies. The electrolytic process not only degrades the colour of the effluent but also transforms recalcitrant substances by direct or indirect oxidation. The ecotoxicological tests are used nowadays as a way to verify the toxicity degree of water bodies polluted by industrial and farming activities. The ecotoxicological tests consist in exposing determined organisms to the samples with the intention to evaluate their toxicity by observing the organisms’ responses. This study had the objective to degrade, by electrolytic process, a simulated textile effluent containing a mixture of Acid Blue 40 and Acid Red 151 dyes and the toxicity evaluation of the treated effluent by ecotoxicological tests. The bioassays used were tests with seeds of Lactuca sativa (lettuce), Eruca sativa (rocket), and Cucumis sativus (cucumber). Tests with the micro crustaceous Artemia salina and the yeast Saccharomyces cerevisiae were also conducted. The electrolytic treatment degraded the initial colour of the textile effluent, and the ecotoxicological tests indicated low toxicity to the treatment.

One of the most important particles of biological origin present in the air is pollen grains of plants. Having basic biological function in the process of pollination, pollen grains of some plant species can cause allergic reactions among 20–30 % of the human population and thus affect their health and overall quality of life. Bearing in mind the potential influence air pollutants and meteorological parameters may have on release of pollen and granules of allergen from pollen, concentrations of air pollutants and 26 different anemophilous aeropollen types as well as meteorological parameters were established in a 5-year period (2009–2013) in Subotica, Northern Serbia. Spearman’s rank correlation was made for statistical analysis of relationships between concentration of some air pollutants (sulphur dioxide, nitrogen dioxide, soot, particulate matter (PM)₁₀ and PM₂.₅), meteorological factors (temperature of air, humidity, wind speed, cloud index) and airborne pollen. In most of the examined years, significant positive correlations were determined between temperature and total pollen concentration, while significant negative correlations were established between humidity as well as cloud index and total pollen concentration, clearly proving the influence these meteorological parameters have on pollination of all examined species.

This study investigates the removal of Cu(II) from aqueous solutions by biosorption-flotation as a function of several parameters, such as collector type, pH, molar ratio, air pressure, time, and initial metal concentration. Dissolved air flotation was applied as a polishing technique for the additional purification of the effluent resulted after biosorption. The obtained results were supported by the physicochemical characteristics of the surfactants used as flotation reagents and suggested that cetylpyridinium bromide (CPB) was the optimum collector for Cu(II) ion removal. Cu(II) removal efficiency exhibited a maximum of 97.09 % in the following operating conditions: biosorption pH 4.5, Cu(II) initial concentration 250 mg/L, biosorbent dosage 0.5 % w/v, agitation rate 200 rpm, temperature 20 °C, biosorption time 30 min, flotation pH 9, air pressure 4.5 × 10⁵ Pa, dilution ratio 3:1, flotation time 10 min, collector CPB 0.01 M, and molar ratio collector/Cu(II) 5 × 10⁻¹:1. The experimental data confirmed that the flotation stage contributed to the optimization of the overall separation process.

Sculpins are widely used as key species for monitoring heavy metal pollution near arctic mine sites. Typically, metal concentrations in liver and muscle tissue have been used as a proxy for metal exposure but such analyses lack temporal information of uptake and accumulation. Otoliths (ear bones) are considered metabolically stable and can potentially contain a complete record of the fish’s metal exposure history. To investigate the otolith chemistry of sculpins and the potential of these as records of metal exposure, common sculpins (Myoxocephalus scorpius) were collected at five sites near a former Pb–Zn mine in West Greenland. Otoliths were analyzed by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) for 12 elements of which Mg, Mn, Sr, Ba, and Pb were detected. The highest Pb concentrations were found within the otoliths from the most Pb-polluted sites near the mine (up to 0.6 ppm), and decreasing concentrations were observed in a gradient away from the mine. Notably, Pb and Sr variations were closely correlated and showed an annual oscillatory pattern with peaks consistently found in the winter zones. It is not clear to what the extent high winter-time accumulation of Pb in the otoliths is due to high winter-time exposure of Pb through diet or water and/or to physiological processes such as growth in the sculpins. The study indicates that LA-ICP-MS analyses of sculpin otoliths have the potential to become a valuable method for assessing time-resolved metal loading near mine sites but also that more studies are required to investigate the links between metal sources, pathways, and processes affecting otolith metal deposition.

Biofiltration of an air stream polluted with diffuse CH₄ concentrations of 0.19 % (v v⁻¹) was carried out. These emissions can be encountered at different industrial facilities such as wastewater treatment plants and landfills. The effect of ammonium supplied in the nutrient solution was studied in a range from 0 to 1 g N-NH₄ ⁺ L⁻¹, taking account its effect on CH₄ removal efficiency (RE), CO₂ production, ammonium conversion and the occurrence of exopolymeric substances. Additional batch assays were performed in order to evaluate the most suitable pH and temperature ranges for the biomass used as inoculum. A conventional biofilter was operated along 225 days achieving maximum CH₄ elimination capacities of up to 11.2 g CH₄ m⁻³ h⁻¹, corresponding to REs of 62 %, using 0.52 g N L⁻¹ of ammonia as nitrogen source in the nutrient solution and operating at an empty bed residence time of 4.4 min. CO₂ production values confirmed that most of this elimination was biological and not absorption into the liquid phase. The occurrence of instability periods resulted in a clear increase of the soluble microbial products (SMPs) contained in the liquid phase, especially in the protein fraction, which could be used as a monitoring tool to follow the stress conditions of the biofilter. Results indicate interesting links between the performance of the biofilter and the presence of extracellular polysaccharide and protein concentration in the liquid phase, with increasing concentrations detected when the process was not stable.

Photosynthetic process is a good approach to discriminate cadmium-tolerant species, because it is reported as one of the most sensitive processes. Our goal was to measure Elephantopus mollis Kunth (Asteraceae) tolerance, determining the interference of Cd on the photosynthetic process. For this, a hydroponic experiment design was conducted in nutrition solution with concentrations of 0 (control), 10, 50, and 100 μM of cadmium (Cd). Measures of photosynthesis performance were obtained, for example, gas exchange, photosystem integrity, chlorophyll content, leaf growth rate, root length, and dry weight. In addition, cadmium and zinc concentrations were measured. Furthermore, results were linked to phytoremediation potential. Our specific questions were as follows: (1) Can the photosynthetic apparatus of E. mollis deal with cadmium stress? (2) Is E. mollis able to accumulate cadmium and maintain zinc level? (3) Is E. mollis a tolerant or sensitive species? (4) Can any phytoremediation practice be suggested from these results? Our results showed that E. mollis can deal with cadmium toxicity up to 10 μM Cd. Moreover, this plant is a potential hyperaccumulator, which can accumulate 248 mg Cd kg⁻¹ dry weight. However, at concentrations of 50 and 100 μM Cd, this species was sensitive and cadmium toxicity affected both biochemistry and photochemistry phases of photosynthesis on account of negative changes on gas exchange, fluorescence chlorophyll, and chlorophyll content. Nevertheless, these results did not compromise the research about its tolerance at lower concentrations of cadmium.