To offer scientific data support for remediation of Cd-contaminated paddy soils under reasonable water condition, pot experiment was conducted to study the effects of moisture management and amendments on Cd immobilization in a paddy soil. Application of biochar combined with organic fertilizer reduced the exchangeable Cd by 20.4, 15.7, and 13.0 % and brown rice Cd by 43.8, 35.5, and 42.1 % under continuous flooding, conventional irrigation, and wetting irrigation, respectively, compared to the controls. Under no amendments, the content of Fe(II) in root coating in the continuous flooding treatment was 2.3 and 3.6 times of that in the conventional and wetting irrigation treatments, but Cd in root coating in the continuous flooding treatment was only 82.6 and 73.8 % of that in the conventional and wetting irrigation treatments. Applying amendments increased the Fe(II) in root coating by 27.3, 59.1, and 65.0 % but reduced the Cd in root coating by 33.6, 26.5, and 25.1 % under continuous flooding, conventional irrigation, and wetting irrigation, respectively. The lower bioavailability of Cd in paddy soil and the competition for adsorption sites in root coating of rice plant between Cd²⁺and Fe²⁺reduced from bivalent ions jointly caused the lower brown rice Cd in amended soils.

In this work, a new step was added to the classic route of iron-pillared clay obtention, resulting in a material with both magnetic and oxidative properties. The saturation of the material surface intercalated with trinuclear acetate-hydroxo iron (III) nitrate in glacial acetic acid atmosphere before heat treatment promoted magnetic phase formation (FePMAG). The material was characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), nitrogen adsorption/desorption isotherms, scanning electron microscopy coupled with energy dispersive spectroscopy (SEM/EDS), and X-ray photoelectron spectroscopy (XPS). FePMAG showed an increase of 0.57 nm in basal spacing which contributed to the specific surface area increase from 39.1 to 139.2 m²/g. The iron phase identified by XRD and XPS was maghemite, with a little presence of hematite formed by the trinuclear acetate-hydroxo iron (III) nitrate decomposition during heat treatment. In the adsorption tests, FePMAG displayed a good capacity for organic dye methylene blue (MB) removal, reaching 41 % at 150 min. Under photo-Fenton conditions, the material showed an excellent MB oxidation capacity, completely removing the color of the solution within 90 min. Identification of the oxidation products with lower molecular (m/z = 160, 220, and 369) mass was performed by electrospray ionization mass spectroscopy (ESI-MS).

Iguaçu River is the second most polluted river of Brazil. It receives agrochemicals and contaminants of urban and industrial sources along its course. A multibiomarker approach was employed here to evaluate the health of a small characin (Astyanax spp.) at two sites along the river, sampled during a dry (autumn) and a rainy (spring) season. Biomarkers were condition factor and somatic indices (gonads and liver); genetic damage (comet assay and micronucleus test); enzyme activities such as hepatic catalase (CAT) and glutathione S-transferase (GST), lipoperoxidation (LPO), branchial and renal carbonic anhydrase (CA), acetylcholinesterase (AChE) in the muscle and the brain, histopathology of the liver and gills, and concentrations of polycyclic aromatic hydrocarbons (PAHs) in bile. There were no consistent differences in biomarker responses between the two study sites. Some biomarkers revealed greater potential impact in the rainy season, when increased amounts of contaminants are washed into the river (combined CAT inhibition and LPO increase, CA upregulation). Other biomarkers, however, revealed potential greater impact in the dry season, when contaminants potentially concentrate (GST induction, AChE inhibition, and liver histopathological alterations). Although of a complex nature, field experiments such as this provide rich data for monitoring protocols and assessment of general risk of exposure to pollutants of river systems.

The contamination of phthalate esters (PAEs) has become a potential threat to the environment and human health because they could be easily released as plasticizers from the daily supply products, especially in polyethylene films. Concentration levels of total six PAEs, nominated as priority pollutants by the US Environmental Protection Agency (USEPA), were investigated in soils and vegetables from four greenhouse areas in suburbs of Nanjing, East China. Total PAEs concentration ranged from 930 ± 840 to 2 450 ± 710 μg kg⁻¹ (dry weight (DW)) in soil and from 790 ± 630 to 3 010 ± 2 130 μg kg⁻¹ in vegetables. Higher concentrations of PAEs were found in soils except in Suo Shi (SS) area and in vegetables, especially in potherb mustard and purple tsai-tai samples. Risk assessment mainly based on the exposures of soil ingestion and daily vegetable intake indicated that bis(2-ethylhexyl) phthalate (DEHP) in the samples from Gu Li (GL) and Hu Shu (HS) exhibited the highest hazard to children less than 6-year old. Therefore, the human health risk of the PAEs contamination in soils and vegetables should greatly be of a concern, especially for their environmental estrogen analog effects.

In the spring 2012, post-flotation tailings of the inactive impoundment Lintich (Slovakia) were sampled. In the impoundment sediment and also in its surrounding, we detected concentration of Pb, Zn, Cd, Cu, and Ba exceeding limiting values. We detected low values of the microbial biomass carbon and microbial activity in the impoundment sediment (LiS) and its dam (DAM) along with potential respiration stayed relatively low and therefore also substrate availability index and metabolic quotient (qCO₂) were higher in the control sample (REF) than in the LiS and the DAM. The low qCO₂ level indicates that microbial community, despite of dangerously high levels of heavy metals in sediment, is still able to sufficiently utilize sources of available organic carbon. Anyway, we could doubt function of the metabolic index as universal indicator of environment conditions, regarding the anthropogenic substrates. We confirmed changes in composition of the mite communities along gradient dam—impoundment. The percentage of eudominant, recendent, and subrecendent species increased at the expense of dominants and subdominants, all together with decreasing diversity and equitability of the community. We identified species Chamobates borealis, Carabodes rugosior, Metabelba propexa, and Pergalumna nervosa with negative respond under the heavy metal stress. Species Adoristes ovatus was indifferent and Dissorhina sp., Hafenrefferia gilvipes, and Oppiella nova prospered under the loaded conditions. Forty years after experimental afforestation, we expect specific community of actively surviving microorganisms and Oribatida species detected in the DAM are usual in the greatly degraded habitats or on sites in the early succession.

Guiyu is one of the most heavily chromium-polluted areas in China due to the numerous informal electronic waste (e-waste) recycling activities. A 3-year (2004, 2006, and 2008) independent cross-sectional study on blood chromium (BCr) levels of 711 children from Guiyu and a control area was investigated. Questionnaire completed by parents/guardians was used to assess the risk factors of chromium (Cr) exposure, while physical examination, for the year 2008 only, was used to evaluate the effects of long-term exposure to Cr on child physical development. Children living in Guiyu had significantly higher BCr levels compared with those living in Chendian at the same period from 2004 to 2008 (P < 0.001). The predominant risk factors related to elevated child BCr levels included the use of house as a family workshop, parent involved in e-waste recycling, and child residence in Guiyu. Children’s weight and chest circumferences in group with high exposure to Cr (upper quartile) were higher than in the low-exposure group (P < 0.01), although the difference was less significant for boys between the two groups (P < 0.05). The results suggest that elevated child BCr in Guiyu due to informal e-waste recycling activities might be threatening the health of children, with implications on physical growth and development.

This paper reports the connections between red blood cells abnormality risk of petrochemical workers and their exposure to airborne polycyclic aromatic hydrocarbons (PAHs). Urinary 1-hydroxypyrene (1-OHP), as the biomarker of PAHs exposure, was adopted to assess the exposure risk of the petrochemical workers to PAHs in Xigu, the west suburb of Lanzhou where petrochemical industries are located. Fifty-three workers, sub-grouped to 36 petrochemical workers and 17 office workers, participated in this investigation. Logistic regression model and spearman correlation analysis were performed to estimate the associations between PAHs exposure levels and red blood cells abnormality risk of petrochemical workers. Strong associations between some red cell indices (MCH, MCHC, RDW) and 1-OHP concentration were found. Results also show that the red blood cells abnormality risk increased with increasing PAHs exposure level. Compared with office workers, risk level of red blood cells abnormality in petrochemical workers was higher by 41.7 % (OR, 1.417; 95 % CI: 0.368–5.456) than that in office workers. This result was verified by the tissue-to-human blood partition coefficient for pyrene and 1-OHP. The quantitative assessments of the potential health risk through inhalation exposure to PAHs were conducted using the Incremental Lifetime Cancer Risk (ILCR) model. It was found the ILCR from inhalation exposure to PAHs for the petrochemical workers ranged from 10⁻⁵ to 10⁻⁴ with 95 % probability, indicating that petrochemical plant workers were under a high potential cancer risk level.

Nitrous oxide (N₂O) is emitted from a modified Ludzak–Ettinger (MLE) process, as a primary activated sludge system, which requires mitigation. The effects of aeration rates and internal recycle flow (IRF) ratios on N₂O emission were investigated in an MLE process fed with glycerol. Reducing the aeration rate from 1.5 to 0.5 L/min increased gaseous the N₂O concentration from the aerobic tank and the dissolved N₂O concentration in the anoxic tank by 54.4 and 53.4 %, respectively. During the period of higher aeration, the N₂O–N conversion ratio was 0.9 % and the potential N₂O reducers were predominantly Rhodobacter, which accounted for 21.8 % of the total population. Increasing the IRF ratio from 3.6 to 7.2 decreased the N₂O emission rate from the aerobic tank and the dissolved N₂O concentration in the anoxic tank by 56 and 48 %, respectively. This study suggests effective N₂O mitigation strategies for MLE systems.

Our research provides the first complete year-long dataset of wet deposition of trace elements in the high Himalayas based on a total of 42 wet deposition events on the northern slope of Mt. Qomolangma (Everest). Except for typical crustal elements (Al, Fe, and Mn), the concentration level of most trace elements (Sc, V, Cr, Co, Ni, Cu, Zn, As, Mo, Cd, Sn, Cs, Pb, Bi, and U) are generally comparable to those preserved in snow pits and ice cores from the nearby East Rongbuk Glacier. Cadmium was the element most affected by anthropogenic emissions. No pronounced seasonal variations are observed for most trace elements despite different transport pathways. In our study, the composition of wet precipitation reflects a regional background condition and is not clearly related to specific source regions. For the trace element record from ice cores and snow pits in the Himalayas, it could be deduced that the pronounced seasonal patterns were caused by the dry deposition of trace elements (aerosols) during their long exposure to the atmosphere after precipitation events. Our findings are of value for the understanding of the trace element deposition mechanisms in the Himalayas.

Spatial and temporal distributions of concentrations of polycyclic aromatic hydrocarbons (PAHs) in surface sediments and dated sediment core from Taihu Lake in eastern China were determined. The sum of concentrations of PAHs (sum of total 16 USEPA priority PAH (∑PAHs)) of the entire Taihu Lake ranged from 2.9 × 10²to 8.4 × 10² ng/g dry mass (dm). Concentrations of ∑PAHs in surface sediments near more urbanized regions of the lake shore were greater than those in areas more remote from the urban centers. Temporal trends in concentrations of ∑PAHs ranged from 5.1 × 10²to 1.5 × 10³ ng/g dm, increasing from deeper layers to surface sediments with some fluctuations, especially in the past three decades after the inception of China’s Reform and Opening Up Policy, in which China’s economy and urbanization underwent rapid development. Forensic analysis of surface sediments indicates that PAHs originated primarily from combustion of grass/wood/coal except for the special function water area, which was most likely influenced by petroleum products of traveling vessels. Vertical profiles of relative concentrations of PAHs suggested that the contribution of lesser-molecular-weight PAHs was gradually decreasing, while due to the heavier consumption of petroleum products, the proportion of greater-molecular-weight PAHs was increasing. When assessed by use of the rather conservative, apparent effect threshold method, concentrations of ∑PAHs in sediments from most locations in Taihu Lake are predicted to pose little risk of harm to benthic invertebrates.