The National Environment Council (CONAMA Resolution 375/06) defined to achieve sanitation quality parameters, for the use of sewage sludge in agriculture, the adoption of additional pathogen reduction processes is necessary. Sludge that is stored for longer periods generally shows higher levels of sanitation, particularly on the helminth egg inactivations which are among the most resistant pathogens. The objective of this study was to monitor the Ascaris egg removal and inactivation efficiency of long-term storage of sludge from septic tanks and up-flow anaerobic sludge blanket (UASB) reactors, besides evaluating the influence of covering and manually revolving or stirring the sludge over a 2-year period. The study was undertaken in the cities of Fazenda Rio Grande and Apucarana, Southern Brazil. In total, 18 experimental treatments were installed and nine samples were assessed at weeks 0, 4, 9, 13, 17, 30, 47, 61, and 104. The standard defined in the CONAMA for class A sludge (one viable egg per 4 g TS) was reached for all treatments at 9 weeks of storage. Two years of storage were necessary in order for the covered, UASB-centrifuge sludge to reach CONAMA standards. Of the six treatments using septic sludge, only one achieved the established standard. This treatment was realized in Apucarana and involved a revolving/stirring process. The period of 104 weeks of storage of the septic sludge was not sufficient to completely inactivate Ascaris eggs for the other treatments. Between study locations, Apucarana performed better than Curitiba which is likely due to greater levels of insolation and temperature.

The Potiguar Basin has oil and gas production fields offshore and onshore. All treated produced water (PW) from these fields is discharged through submarine outfalls. Although polycyclic aromatic hydrocarbons (PAHs) are minor constituents of PW, their input into the marine ecosystem is environmentally critical due to potential ecological hazards. A 2-year monitoring program was conducted in the vicinity of the outfalls to evaluate PAH bioaccumulation in marine life from PW discharges. The study was performed using transplanted bivalves Crassostrea brasiliana and semipermeable membrane devices (SPMDs) to measure PAH concentrations via bioaccumulation and in seawater. The bioaccumulation of PAH in transplanted bivalves reached up to 1105 ng g⁻¹ in the vicinity of the monitored outfall. Significantly lower PAH concentrations were found in the reference area in comparison to the studied area around the outfalls. Time-integrated PAH concentrations in seawater ranged from 38 to 0.3 ng L⁻¹ near the outfalls and from 10 ng L⁻¹ to not detected in the reference area. Both measurement techniques were found to be effective for determining a gradient of descending PAH concentrations from the outfalls. In addition, this study also evaluated the bioavailability of PAH for local marine biota and provided information about the influence of PW discharges on the water quality of marine ecosystems.

Drought stress is one of the major environmental factors responsible for reduction in crop productivity. In the present study, responses of two maize cultivars (Rung Nong 35 and Dong Dan 80) were examined to explicate the growth, yield, leaf gas exchange, leaf water contents, osmolyte accumulation, membrane lipid peroxidation, and antioxidant activity under progressive drought stress. Maize cultivars were subjected to varying field capacities (FC) viz., well-watered (80 % FC) and drought-stressed (35 % FC) at 45 days after sowing. The effects of drought stress were analyzed at 5, 10, 15, 20, ad 25 days after drought stress (DAS) imposition. Under prolonged drought stress, Rung Nong 35 exhibited higher reduction in growth and yield as compared to Dong Dan 80. Maize cultivar Dong Dan 80 showed higher leaf relative water content (RWC), free proline, and total carbohydrate accumulation than Run Nong 35. Malondialdehyde (MDA) and superoxide anion were increased with prolongation of drought stress, with higher rates in cultivar Run Nong 35 than cultivar Dong Dan 80. Higher production of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) and glutathione reductase (GR) resulted in improved growth and yield in Dong Dan 80. Overall, the cultivar Dong Dan 80 was better able to resist the detrimental effects of progressive drought stress as indicated by better growth and yield due to higher antioxidant enzymes, reduced lipid peroxidation, better accumulation of osmolytes, and maintenance of tissue water contents.

Increased emissions of fluoride into the atmosphere contribute to reducing the sustainability of agricultural systems worldwide. In order to improve the understanding of the factors behind such phenomenon, varieties of citrus (Citrus spp.), Valencia sweet-orange, Ponkan mandarin, and Lisbon lemon and coffee (Coffea spp.), Obatã, Catuai, and Apoatã, were treated with fluoride nebulization. The trees were exposed to nebulization for 60 min inside a chamber by using medium (0.04 mol L⁻¹) and high (0.16 mol L⁻¹) doses of fluoridic acid (HF) during three nonconsecutive days in a single week, for a total of 26 days of exposure during the experiment. Sixty days after beginning nebulization, we evaluated leaf gas exchange, (ultra)structural organization, tree growth, and fluoride and nutrient concentrations in plant tissue. Photosynthesis and leaf dry mass of citrus and coffee varieties were affected differently by fluoride toxicity, and based on the tolerance index (relative leaf dry mass of control versus leaf dry mass of trees treated with 0.16 mol L⁻¹ HF), the order of sensitivity for the varieties of each species was as follows: for citrus, lemon > mandarin > sweet-orange; and for coffee, Apoatã > Catuaí > Obatã. The ability of the trees to control fluoride absorption most likely explained this contrast in sensitivity among varieties because both photosynthesis and leaf growth were negatively correlated with leaf fluoride concentration. Although disorganization of the thylakoids, degeneration of vascular cells, and disruption of the middle lamella occurred in leaves of all varieties exposed to fluoride, the more severe damage was observed in those with greater sensitivity to the pollutant (i.e., lemon and Apoatã coffee). Taken together, these results provided insights into the factors that explain poor performance of citrus and coffee trees under fluoride pollution and also revealed the traits driving the tolerance of these crops such a limiting condition, which included a combination of the following: (i) reduced fluoride absorption, (ii) increased photosynthesis, and (iii) improved maintenance of the ultrastructural organization of leaves.

Inorganic arsenic occurs mainly in As(III) and As(V) states in water environment, but arsenite is more toxic and difficult to remove than arsenate by usual adsorption processes. To achieve the in situ oxidation of As(III) and simultaneous removal of both As(III) and As(V) in water, a novel-layered double hydroxide (Mg–Fe–S₂O₈–LDH) with the intercalation of persulfate has been designed and synthesized by a calcination-reconstruction method. The arsenic adsorption performances and removal mechanism with the Mg–Fe–S₂O₈–LDH material were studied. The experimental result showed that, since the strong oxidation ability of the exchangeable persulfate ions from the LDH, the As(III) species in water were almost completely oxidized to the As(V) state and simultaneously adsorbed onto the Mg–Fe–S₂O₈–LDH. It was found that the maximum adsorption capacity for As(III) and As(V) in single-pollutant system was 75.00 and 75.63 mg·g⁻¹, respectively. When the adsorbent dosage was 0.5 g·L⁻¹ for a mixed As(III) and As(V) solution, the batch experiment showed that the residual arsenic concentration can be reduced from 1 mg·L⁻¹ to lower than the limit value of drinking water standard recommended by WHO. It indicated that the synthesized Mg–Fe–S₂O₈–LDH is a potential attractive adsorbent for simultaneous removal of As(III) and As(V) in water.

Heavy metal pollution in urban soil has become a serious environmental issue in China since the last three decades. Attention has been given to the investigation of soil contamination; however, there is little information available on the variation of heavy metal pollution in soils. To resolve this problem and provide references on similar regions, 18 topsoil (0∼20 cm) samples were collected from identical sites of districts that with different functions in Kaifeng City in 1994 and 2012. Total contents of As, Cd, Hg, and Pb were determined by standard methods. The variation of heavy metal pollution was evaluated by using geoaccumulation index and pollution load index. Results show a descending trend in heavy metal pollution of soil in Kaifeng City that demonstrated over the last 20 years, though there are still some contaminations in 2012. The highest concentration of soil metal was observed in industrial district, followed by the cultural and educational district, administrative business district, and entertaining district in turn. Concentrations of Pb in all soils and As in most soils were higher in 2012 than that in 1994, which mainly due to the rapid increase of motor vehicles and domestic garbage. Meanwhile, the concentrations of Hg and Cd in most soils were lower in 2012 than that in 1994, as the relocation and shutdown of industry and the wide development of environmental facilities. Land use and land cover change in urban areas can effect on soil metal pollution. When farmland transforms into urban land, the concentrations of soil metals would be increased, and also, the soil pollution will increase severely.

Textile dyes and antibiotics are two main classes of environmental pollutants which could be found in soil and water. Those persistent pollutants can have a negative influence on plant growth and development and affect the level of secondary metabolites. In the present work, we studied the effect of textile dyes and antibiotics on total leaf flavonoid contents in wheat (Triticum aestivum L.). Contaminant solutions were applied daily using concentrations of 0.5 mg L⁻¹ (lower) and 1.5 mg L⁻¹ (higher dose) for either 1 or 2 weeks. We observed that exposure to the higher concentration of textile dyes resulted in a reduction in flavonoid content while antibiotics enhanced flavonoid contents at lower doses of exposure and reduced at higher doses of exposure. These results suggest that diffuse chronic pollution by artificial organic contaminants can importantly alter antioxidative capacity of plants.

Mesoporous magnetic ferrum-yttrium (Fe-Y) binary oxide was first synthesized as an effective absorbent for the removal of arsenite [As(III)] and arsenate [As(V)] from aqueous solution. The adsorbent was characterized by field emission scanning electron microscopy (FESEM), energy dispersion X-ray spectrometer (EDX), vibrating sample magnetometer (VSM), X-ray photoelectron spectra (XPS). A series of batch experiments were conducted to estimate the adsorption capacity of arsenic and to investigate the effect of solution pH and coexisting anions on the removal of arsenic. The results demonstrate that the adsorption of arsenic by the adsorbent was pH-dependent. The optimal adsorption was realized at pH 4 for As(V) and at pH 5 for As(III). The maximum capacity of As(V) and As(III) obtained in this study was 200 and 73 mg g⁻¹, respectively. The anions concluding sulfate, chloride, and nitrate exerted a weak impact on As(V) removal, whereas phosphate greatly suppressed the adsorption of both As(III) and As(V) through competing with arsenic species for active adsorption sites on the surface of the adsorbent. All above suggest that the novel adsorbent not only works efficiently for arsenic removal, but also is stable in a wide solution pH range, which is conducive to the practical application for wastewater treatment.

The contribution of atmospheric deposition to the metal load at the outlet of a small urban catchment (Pin Sec, France) was studied. A new method, which takes into account the type of urban surfaces (glass, tile, bitumen, zinc sheet, grass, facade coating, and slate) as well as turbulence and local micrometeorology, was developed to measure atmospheric dry deposition. Dry deposition, wet deposition, and stormwater runoff load were all measured from September 2010 to August 2011. At the annual scale, atmospheric deposition was not a major contributor to the metal load at the outlet of this small catchment. Wet deposition however ranged from <1 to 29 %. The contribution of dry deposition (generally less than 5 %) was especially low and appeared to be smaller than that reported in previous studies. On this catchment, the majority of the metal load could be attributed to stormwater runoff (64–99 %). This methodology looks promising and should be taken into consideration when conducting new research on the contribution of atmospheric deposition to the pollutant load in urban catchments.

Currently, there are increasing efforts to utilize nanoremediation as an environmental technology for cleaning up polluted environments using nanoscale zero-valent iron (nZVI); however, concerns exist regarding the long-term environmental impact of this strategy. In this study, an innovative methodology for evaluating nZVI impact on soil bacteria is utilized, based on transcriptional analysis of three novel biomakers: tnaA, sodB and trx genes. At the same time, classical toxicological bioassays with the nematode Caenorhabditis elegans were performed. Microcosms treated with 1, 5 and 10 % w/w of nZVI were set up using a commercial standard soil and incubated for 21 days. The tnaA gene, involved in indole production, was significantly upregulated at all assessed nZVI concentrations, suggesting that bacterial cells used this molecule to inform the rest of the community about the changes produced upon nZVI soil treatment. The higher the exposure time, the lower nZVI concentration needed to detect these changes. Consequently, soil bacteria activate a cellular adaptive response to cope with the nZVI-induced oxidative stress, increasing the expression of genes encoding key reactive oxygen species (ROS)-scavenging enzymes; in fact, an upregulation of the sodB and katB genes was recorded upon nZVI exposure. On the contrary, C. elegans survival and growth endpoints were not affected at any nZVI concentration whereas the exposure time significantly increased nematode growth in the soil. Therefore, despite the lack of toxicity revealed by the classical conducted tests, the transcriptional analyses demonstrated the usefulness of combining the set of proposed biomarkers for early detection and monitoring the impact of nZVI on soil bacteria after environmentally important periods of exposure.