Characterization and analysis of specific energy consumption in the Brazilian agricultural sector The original version of this article unfortunately contained a mistake: Juliana Prado was not listed among the authors. The complete authors are given above.

Correction to: Technical assessment and decision making for the environmental recovery of waterways and their banks: a science-based protocol The original version of this article unfortunately contained a mistake. The spelling of the name of W. Francesconi was incorrect. The corrected name is given above.

Evaluation of heavy metal contamination in soil using geochemical indexing approaches and chemometric techniques Abstract This work attempts to make an appraisal of soil regime pollution by heavy metals in the hilly tracts of Nalagarh valley, Himachal Pradesh, India, using geochemical indexing approaches and chemometric techniques. Nalagarh valley houses various industries and is a centre of economic activities in Himachal Pradesh. Fifteen soil samples were collected and analysed for arsenic, cadmium, chromium, copper, iron, manganese, nickel, lead and zinc. Concentrations of these heavy metals lie within the prescribed limits of most developed countries including those of India with their average concentrations too lying within the crustal average shale values except that of cadmium, but assessment by geochemical indexing approaches such as geoaccumulation index, enrichment factor, contamination factor, pollution load index and ecological risk indicates that cadmium, lead and copper are slowly contaminating the valley soil with potential ecological risk index varying between 48.07 and 157.00, which implies low-to-moderate risk intensity of metals on ecosystem. Principal component analysis extracts three principal components: Principal Component 1 loading on the metals (arsenic, cadmium, chromium, iron, manganese and lead) is regulated by mixed factor, Principal Component 2 (copper, lead and zinc) is influenced by anthropogenic inputs and Principal Component 3 (chromium and manganese) is influenced by weathering of parent materials. Cluster analysis has been integrated with potential ecological risk index to appraise its relations and validate the pollution factors affecting the potential ecotoxicity in the soil regime. Geochemical indexing approaches coupled with chemometric analysis, therefore, offer a robust method in detecting pollution and identifying mitigation measures.

Treatment optimization and performance evaluation of water supply schemes: a case study on Akure and Environs Abstract Efficient treatment, optimization and reduction in corrosion of sewage pipe networks are crucial for water resources engineering works and environmental experts. This paper revealed treatment optimization and performance evaluation of water supply schemes using Akure and Environs as a case study. Laboratory analysis of the properties of raw and treated water was compared with World Health Organization standard for safe drinking water. A regression model using Minitab and an optimized model using Microsoft Excel method were used. A suitable model and cost estimates were also developed for the optimization of both plants. Discussion of the problems faced with water production in the Ondo and Igbara-Oke plants in Nigeria and the cost estimates of the solutions proffered were done. The adoption and implementation of these solutions for the treatment plants will assist the government maintenance policies on sustainable water supply and optimization for other treatment plants. Training, development and capacity building for sustainable water resource management is very crucial in Nigeria. More research should be funded and carried out along this direction.

Sequential determination of five heavy metal ions in Brazilian phosphate fertilizers and surface waters by stripping voltammetry Abstract A method comprised of multi-detection steps for the sequential determination of uranium, cadmium, lead, thallium, and silver, using electroanalytical tools, is proposed herein. Firstly, adsorptive stripping voltammetry was applied to assay the U(VI)–cupferron complex in the differential pulse mode. In sequence, using the same aliquot of the sample, the quantifications of cadmium and lead were performed simultaneously by differential pulse anodic stripping voltammetry with the environmentally friendly bismuth film electrode. Due to the overlapping peaks of cadmium and thallium, the addition of EDTA enabled the determination of thallium by anodic stripping voltammetry. On employing the ex situ bismuth-film-modified electrode, the current intensity increased for the four heavy metal ions. After the removal of the bismuth film, silver was quantified at a glassy carbon electrode by anodic stripping voltammetry, as the last step of the multi-detection method. The method was successfully applied to phosphate fertilizer samples after open-vessel wet decomposition (HNO3/H2O2). Uranium was detected in the range of 36.2–144.0 mg kg−1. Cadmium and lead were detected in concentrations of up to 41.4 and 204.0 mg kg−1, respectively. The concentrations of thallium and silver were below the detection limits. Surface water samples (river water and lagoon water) were also analyzed with respect to the heavy metal ions. Validation was performed using the standard reference materials SRM-695 (phosphate fertilizer) and SRM-1643e (water).

Determination of micropollutants in wastewater matrix using gas chromatography–mass spectrometry after optimization of dispersive liquid–liquid microextraction Abstract In this study, an experimental design was used to optimize dispersive liquid–liquid microextraction for the extraction/preconcentration of micropollutants that have endocrine disruption potential, for the determination by gas chromatography–mass spectrometry. The analytes were selected from endocrine disrupting chemicals, such as pesticides, phthalates, hormones, alkyl phenols and pharmaceuticals. The most influential parameters of the extraction method determined in a pre-optimization step were included in the design model to determine their optimum amounts and to evaluate their interactions in a series of combinations. The design model predictor was used to obtain optimum experimental values, with which analytical performance of each analyte was determined with calibration plots. Deuterated bisphenol A (BPA D16) was added as an internal standard to all samples and calibration standards to improve the precision of the results. The limits of detection for analytes ranged between 0.10 and 16 µg/L. The developed method was applied to synthetic and municipal wastewater samples, and the results obtained from spiked recovery tests ranged between 79 and 113%. These results confirmed the applicability of the method for the selected sample matrices. The complex nature of the samples tested in this study affected the recovery of analytes. However, matrix matching calibration was employed to overcome the matrix effects and this improved the recovery results.

Potential use of treated domestic sewage for cultivation of biofuel crops in Egypt Abstract Sewage treatment in a biological compact unit and effluent reuse for cultivation of Jojoba, Jatropha and Castor beans was examined. The biological compact unit includes three zones: settling and anaerobic, aerobic biofilm and final sedimentation. Quality of raw sewage and treated effluents was monitored. Impact of water quality on growth rate of biofuel crops and soil properties was investigated. Reuse of raw sewage for irrigation of biofuel crops has major impact on microbial quality and heavy metals concentration of irrigated soil. Sequence of heavy metals accumulation in the soil was Zn > Cu > Cr > Pb. Castor beans irrigated with the final effluent has the highest growth rate and crop yield followed by Jatropha and Jojoba. Growing Castor beans using treated sewage is economically feasible since the plant produces harvestable seeds during the first year and thereafter. Castor beans yield was highest (1.78 ton/ha) with the final effluent. Estimated market price is $1241/ha.

Environmental assessment of toxic metals from Canal on Mehran University water treatment plant, Jamshoro, Pakistan Abstract The main aim of this study was to evaluate the heavy metals in Mehran University water treatment plant, Jamshoro District, Sindh, Pakistan. The water samples were collected throughout the year (June 2016 to May 2017) from different locations such as raw water source (Kalri Baghar feeder), Mehran University water treatment plant and water distribution network from water treatment plant to the departments of Mehran University. The water samples from different locations were coded as S1 (Kalri Baghar Feeder/intake raw water source), from Mehran University water treatment plant (S2–S4), i.e., S2 (sedimentation tank outlet), S3 (post-filtration), S4 (Mehran University storage tank) and at last from Mehran University department, i.e., S5 (institute of water resources management), respectively. The atomic absorption spectrometry technique was used to evaluate the levels of heavy metals in water samples from different locations. The ranges of mean concentrations were analyzed from different locations (S1, S2, S3, S4 and S5) in Mehran water treatment plant such as for zinc from 60.368 to 137.6 µg/L, for copper from 1.82 to 4.08 µg/L, for chromium from 1.709 to 3.448 µg/L, for arsenic from 3.08 to 4.29 µg/L, for mercury and cadmium were observed under below detection limit. The detection limit of these metals was observed at 1, 0.5, 0.2, 2, 2 and 0.05 µg/L for zinc, copper, chromium, arsenic, cadmium and mercury, respectively. The recovery of the spike analyte was observed from 95 to 103% in different locations. The observed concentrations of selected heavy metals are under World Health Organization and National Environmental Quality Standards guideline limits.

Recycling of different solid wastes in synthesis of high-order mesoporous silica as adsorbent for safranin dye Abstract Silica mesoporous materials of MCM-48 type were successfully synthesized using different types of silica-bearing solid wastes including silica fume, silica gel from rice husk ash and glass wastes as adsorbents for safranin dye. This represents an effective recycling technique for the production of such advanced materials from low-cost solid wastes instead of chemicals. The materials were synthesized by hydrothermal treatment process for 48 h in the presence of an organic template at 110 °C followed by calcination at 550 °C. The products were identified utilizing XRD and SEM analyses to investigate the structural and the morphological features. The used silica precursors exhibit a significant effect on the morphologies of synthetic MCM-48 materials and their adsorption behaviors. The adsorption properties were addressed based on a series of traditional and advanced equilibrium models. The adsorption results reflected the higher capacity for the dye molecules using glass-based MCM-48 than fume-based MCM-48 and rice silica gel-MCM-48. However, the uptake results of glass-based MCM-48 is of monolayer type and can be explained by Langmuir model and the uptake by the other synthetic products (fume-based MCM-48 and rice gel-based MCM-48) is of multilayer type and fitted with Freundlich model. The mathematical parameters of advanced isotherm model (monolayer model of two energies) reflected the theoretical values of adsorption capacity, number of adsorbed safranin molecules per active site, the average number of sites occupied by dye and the density of the present receptor sites.

Study of plastics elimination in bioleaching of electronic waste using Acidithiobacillus ferrooxidans Abstract Polystyrene, acrylonitrile butadiene styrene, and polypropylene are the main polymers in E-waste, existing about 31%, 16%, and 13%, respectively. In this research, the effects of the elimination of low-density materials (such as polymers and plastics) were studied using the shaking table method. Bioleaching of Cu and Ni against the original sample (Sample #1) and pre-treated sample without low-density materials (Sample #2) was compared. The amount of bioleached metals and growth characteristics (including pH, Eh, bacterial count) was investigated within 25 days. The analysis of Sample #1 showed that at pulp density of 15 g/l, 94% and 79% of Cu and Ni were recovered maximally, respectively, on 14th day. By using Sample #2, the recovery of Cu and Ni decreased to 87% and 74%, respectively, on 6th day. Chemical characteristics (including recovery, X-ray diffraction, X-ray fluorescence, Fourier transform infrared spectroscopy, and field emission scanning electron microscope) before and after bioleaching of both E-waste samples confirmed that bioleaching was quite effective. This paper proved the great potential of the bio-hydrometallurgical route to recover heavy metals from electronic wastes, in which recovery of Cu and Ni is higher in the presence of low-density materials.