Lake Mallusjärvi in the cultural landscape of Mallusjoki, southern Finland, suffers from algal blooms during summers and oxygen depletions during winters due to increased nutrient input resulting from extensive agricultural activities in the catchment. In this study, a sediment profile from the lake was studied using fossil midge (Diptera: Nematocera) analysis and a hypolimnetic oxygen transfer function was applied to establish baseline conditions of hypolimnetic oxygen. In addition, physical properties of the sediment were determined. The inferred late winter hypolimnetic oxygen content was elevated in the beginning of the sediment sequence, but decreased dramatically at ca. 200 cal BP, as the inferred values indicated frequently anoxic condition coinciding with increased agricultural use in the catchment. The results indicated that dramatic changes have occurred in the taxon composition. The high-oxygen Stempellina–Ablabesmyia monilis-type community first changed to moderate-oxygen Procladius–Stempellinella community, and finally to low-oxygen Microchironomus tener–Chironomus plumosus-type community, following the eutrophication process. These changes in macrobenthic faunal assemblages reproduced considerably higher inferred hypolimnetic oxygen reference condition values for hypolimnetic oxygen, compared to the present status.

The biofilter system containing tire-derived rubber particle (TDRP) filter media was utilized to treat the odorous gas contaminant, hydrogen sulfide, in consideration of the economic advantage of reusing discarded tire materials and the high potential of TDRP media for biofilm attachment. The pilot-scale system having 0.38 m3 of bed volume operated with synthetic hydrogen sulfide gas on continuous basis from a range of 0.34 to 1.15 m3/min. This bioreactor system achieved over 94% removal efficiency at 20–90 ppm of inlet H2S concentration while operating in 20–67 s of empty bed retention time, indicating that overall effective operation was performed at mass loading rates of H2S ranging from 19.6 to 28.5 g H2S/(m3 h). It was apparent by the effectiveness of the system’s performance that this system had the capability to effectively remove hydrogen sulfide with high efficiency over a range of concentrations. A maximum elimination capacity was not found for the biofilter during this study, which tested loading rates between 0 and 30 g H2S/(m3 h).

In recent years, elevated arsenic concentrations in groundwater used for drinking water supplies have been recognised in the Madrid Tertiary detrital aquifer. Although only natural causes have been suggested as the source of arsenic, this study aims to highlight that the anthropogenic contribution cannot be disregarded. During the sub-catchment's areas sampling, we found many geographical sites where natural arsenopyrite [FeAsS] originally encapsulated in pegmatite bodies and quartz veins, was artificially outcropped and dumped out, since mining wastes were scattered and exposed to weathering. Several mineral and ground specimens were collected to analyse its mineralogical and chemical composition by X-Ray Diffraction (XRD) and X-Ray Fluorescence (XRF) spectrometry and by Environmental Scanning Electron Microscope (ESEM). Both, the abundant existence of secondary phases, such as scorodite [FeAsO₄⋅2H₂O] and jarosite [KFe₃(SO₄)₂(OH)₆], much more soluble than arsenopyrite, and the lixiviation experiments of arsenopyrite in acidic media to simulate acid mine drainage (AMD) conditions, usually found in old mining districts, point to a potential risk of arsenic contamination of surface water bodies, which operate as recharged waters of the aquifer in the studied area. The elemental determination of heavy metals present in ground samples by XRF analyses, reaching up to 1,173 mg kg⁻¹ of copper, 347 mg kg⁻¹ of lead and 113,702 mg kg⁻¹ of arsenic; and the physicochemical and arsenic fractionation studies of soil samples, led us to classify the soil as Spolic Technosol (Toxic). The contamination of the area due to old mining activities could release arsenic to Madrid water supplies; accordingly, additional decontamination studies should be performed.

We present here the effects of ambient ozone (O₃)-induced decline in carbon availability, accelerated foliar senescence, and a decrease in aboveground biomass accumulation in the Aleppo pine (Pinus halepensis Mill.). Aleppo pine seedlings were continuously exposed in open-top chambers for 39 months to three different types of O₃ treatments, which are as follows: charcoal-filtered air, nonfiltered air (NFA), and nonfiltered air supplemented with 40 ppb O₃ (NFA+). Stable carbon isotope discrimination (Δ) and derived time-integrated c i/c a ratios were reduced after an accumulated ozone exposure over a threshold of 40 ppb (AOT40) value from April to September of around 20,000 ppb·h. An AOT40 of above 67,000 ppb·h induced reductions in ribulose-1,5-biphosphate carboxylase/oxygenase activity, aboveground C and needle N and K concentrations, the C/N ratio, Ca concentrations in twigs under 3 mm, and the aerial biomass, as well as increases in needle P concentrations and phosphoenolpyruvate carboxylase (PEPC) activity and the N and K concentrations in twigs under 3 mm. Macronutrients losses, the limitations placed on carbon uptake, and increases in catabolic processes may be the causes of carbon gain diminution in leaves which was reflected as a reduction in aboveground biomass at tree level. Stimulation of PEPC activity, the consequent decreased Δ, and compensation processes in nutrient distribution may increase O₃ tolerance and might be interpreted as part of Aleppo pine acclimation response to O₃.

We report the isolation of a new bacterium species (named as DN-06) that degrades pyridine, a model compound containing both carbon and nitrogen, from the aerobic activated sludge in a coking wastewater treatment plant. DN-06 was identified as Achromobacter sp. using 16S rDNA sequence analysis. In batch culture, more than 95% of pyridine (500 mg/L) was degraded within 18 h by DN-06 grown at 35°C and pH 8 with agitation at 170 rpm. Degradation experiments of pyridine at different initial concentrations (50–4,300 mg/L) revealed that pyridine was an inhibitory substrate, and that neither yield coefficient Y nor endogenous decay coefficient K d was a constant. The values of Y and K d were 0.55–0.74 and 0.0032–0.0057 h−1, respectively. Five kinetic models (Haldane, Yano, Aiba, Webb, and Monod) were fitted to the experimental growth kinetic data. Models of Haldane and Yano (correlation coefficient R 2 = 0.929) were the most suitable models. For Haldane kinetic model, the values of μ max, K s, and K i were 0.161 h−1, 142.6 mg/L, and 4234.8 mg/L, respectively. The large values of Y and K i indicated that DN-06 had good tolerance against high pyridine concentrations. These results indicated possible future applications of Achromobacter sp. DN-06 in removing pyridine from industrial wastewaters, as well as in destroying pyridine in concentrated solutions during further treatment of trial water coupling with adsorption technology.

The use of multiwall carbon nanotubes (MWCNT) as an efficient solid extractor in preconcentration/cleanup studies for tin determination in water samples by electrothermal atomic absorption spectrometry (ETAAS) is proposed. In the proposed method, tin adsorption onto MWCNT was carried out by percolating the solution previously buffered (pH 4.79 with 0.24 mol L−1 acetic acid/acetate buffer) at 4.0-mL min−1 flow rate, followed by elution with 1.0 mL of 2.7 mol L−1 HNO3. Factors such as sample pH, preconcentration/cleanup flow rate, type and concentration of eluent, and buffer concentration were appraised and optimized from chemometric tools based on fractional factorial design and Doehlert design. A limit of detection of 0.73 μg L−1 and precision (n = 8) assessed as relative standard deviation of 8.6% and 7.0% for tin concentration of 8.0 and 43.0 μg L−1, respectively, were achieved. Foreign metallic ions (Ni2+, Pb2+, Co2+, Zn2+, Cd2+, Mn2+, and Fe3+) were checked as potential interferents, and no interference was observed up to an analyte/interference ratio of 1:10 (m/v). Direct tin determination by ETAAS in water samples containing high salt amount is drastically affected by background signal. However, previous cleanup of sample by MWCNT has promoted a significant improvement and makes the method useful for tin monitoring in water samples (mineral, lake, mine, and natural waters) by ETAAS. Quantitative recovery values ranging from 91.5% to 103.0% attested the applicability of the proposed preconcentration/cleanup for tin determination in water samples.

This study was conducted to determine the potential of in situ biodegradation and identify the geochemical and microbial processes of the petroleum-contaminated subsurface environment using integrated hydro-bio-geochemical markers so that the risk of contamination to subsurface environment can be better understood. The contamination process and corresponding bio-geo-chemistry were analysed in parallel with geochemical and multi-variant statistical modelling at a petroleum-contaminated site in the northeast China. The total petroleum hydrocarbon analysed in the monitoring wells and soil profile demonstrated heavy contamination with potential risk to human health and eco-environment. Further detailed analysis of petroleum fractions revealed a clear spatial variation of organic compositions in groundwater. It was evident that biodegradation and preferential biodegradability contributed considerably to the fraction distribution pattern, which can also be implicated by carbon and microbial respiration in the subsurface environment. The steady decrease in SO4 2- concentration, detection of S2-, and increase in pH and alkalinity (HCO3 -) in groundwater during the monitoring period demonstrated that sulphate reduction was the dominant biodegradation process in most contaminated zones. The results of statistical analysis further suggested that the hydro-geochemical environment was mainly controlled by the regional hydro-geochemical and sulphate reduction process associated closely with the total petroleum hydrocarbon. Knowledge from the comprehensive study provides useful insight on fate, transport and risk assessment of the petroleum contaminants in the shallow subsurface environment.

The number of chemical compounds in sewage and consequently their release into the environment is increasing. Some of them are toxic and many of them are considered endocrine disrupters. Here, the capacity of three wastewater treatment plants (WWTPs) to remove caffeine, hormones and bisphenol-A was investigated. Bisphenol-A and caffeine are highly water-soluble compounds, as opposed to hormones (estradiol, estriol, and ethynilestradiol) which are hydrophobic compounds. In the Sewage Treatment Plant (SWT)1 the sewage is treated by activated sludge process, in the second plant, SWT2, sewage is treated by upflow anaerobic sludge blanket reactors followed by dissolved air flotation, and in the third, SWT3 sewage is treated by stabilization lagoons. The first lagoon is 3.5 m deep, thus facultative and polishment processes occur. It was speculated that there was a difference in efficiency between the three plants in removing micropollutants. Small differences were found in the amounts removed, probably accounted for by retention time. The caffeine and bisphenol-A were almost completely removed, higher than 90% for both compounds (bisphenol-A and caffeine) in all WWTPs. The hormones, however, had a smaller rate of removal, between 70% and 87%. It is suspected that retention time is essential for removal efficiency, together with type of treatment. In fact, the hormones, caffeine, and bisphenol-A found in the environment definitely come from untreated sewage.

The research was carried out in the spruce forests of Barania Góra (Silesian Beskids, Poland) affected by pandemic dying of trees. Twenty-seven samples were collected from the O layer in two plots: 17 in a cut down forest infested with insect pests (bark beetle) and ten in a 120-year-old healthy forest. The analyses covered basic parameters (pHH2O, pHKCl, worg, Ctot, Ntot, CEC) and the concentrations of aluminium in the fractions leached with 0.1 M BaCl2 (Alexch), 0.5 M CuCl2 and 0.1 M Na4P2O7 (Albio) solutions. The total aluminium concentration in the soil was assayed digesting samples with hydrofluoric acid. The effect of pH and organic matter content on the amount of exchangeable (Alexch) and bioavailable (Alexch) aluminium in the soil was analysed. It has been found that the soils in both plots are strongly acidic and contain 550 to 1,700 mg kg−1 of exchangeable aluminium and 1,200 to 4,800 mg kg−1 of bioavailable aluminium. The lack of disease symptoms in the spruce trees in plot 2 can be explained by the higher content of organic matter in the soil. Unfortunately, one might expect that the high concentration of exchangeable aluminium will also cause the trees in the area to wither.

Arsenic (As)-contaminated irrigation water is responsible for high As levels in soils and crops in many parts of the world, particularly in the Bengal Delta, Bangladesh and West Bengal, India. While arbuscular mycorrhizal (AM) fungi markedly improve phosphorus (P) uptake, they can also alleviate metal toxicity. In this study, the effects of superphosphate and inoculation with the AM fungus Glomus mosseae on P and As uptake of lentil were investigated. Plant height, shoot dry weight, shoot/root P concentration, and shoot P content increased due to mycorrhizal inoculation. However, As concentration in roots/shoots and root As content were reduced, plant height, shoot dry weight, shoot/root P concentration/content, and root As concentration and content increased due to superphosphate application. Root P concentration decreased with increasing As concentration. It was apparent that As concentration and content in shoots/roots increased with increasing As concentration in irrigation water. Superphosphate interaction with G. mosseae reduced the role of mycorrhizal infection in terms of enhancing P nutrition and reducing uptake of potentially toxic As into plant parts. The role and relationship of mycorrhizal in respect of P nutrition and As remediation efficiency in plant parts was established. In conclusion, it was worth alluding to that lentil with AM fungal inoculation can reduce As uptake and improve P nutrition. However, in retrospect superphosphate increased P and As uptake and decreased the role of the mycorrhizal association. This resulted in stimulating increased P uptake while decreasing As uptake in lentil.