Recently, biochar has received significant attention, especially for the removal of potentially toxic elements (PTEs) from water and wastewater. No review has been focused on the potential use of wood-based biochar (WB) for the removal of PTEs in water and wastewater. Here, we have critically reviewed the (i) preparation and characterisation of WB; (ii) removal efficiency of WB for PTEs in water with respect to its physicochemical characteristics, biochar/water ratio, pH, and sorption system; (iii) removal mechanisms of PTEs by WB; (iv) fate of the sorbed PTEs onto WB; and (v) recovery of the sorbed PTEs from the resultant sludge of WB. We also discussed the removal of PTEs by engineered/designer WB as compared to pristine WB. This review demonstrates the overarching scientific opportunities for a comprehensive understanding of using WB as an emerging biosorbent and a promising low-cost and effective material for the remediation of PTEs contaminated water.

Wood-based biochar for the removal of potentially toxic elements in water and wastewater: a critical review

This study was carried out to investigate the current status of groundwater quality in Wuqi County, northwest China. The health risk assessment was also performed to quantify the negative impacts of hexavalent chromium (Cr6+) and nitrate (NO3−) in groundwater on human health by fully considering the gender and age of local residents. For this study, thirty groundwater samples were collected from wells and boreholes distributed in the study area and analyzed for pH, total dissolved solids (TDS), total hardness (TH), major ions (Na+ + K+, Ca2+, Mg2+, HCO3−, SO42−, and Cl−), NO3−, nitrite (NO2−), and Cr6+. Statistical analysis and graphical approaches were adopted to delineate the physicochemical parameters and hydrochemistry of groundwater. Fuzzy comprehensive method was applied in this study to appraise overall groundwater quality. The model recommended by the Ministry of Environmental Protection of the People's Republic of China was selected to assess the non-carcinogenic and carcinogenic risks caused by Cr6+ and NO3− through drinking water intake. Indicated by statistical mean values, the order of cations is Na+ + K+ > Ca2+ > Mg2+, and that of anions is SO42− > Cl− > HCO3−. The averages of TH, TDS, NO3−, and NO2− are 432, 1253, 23.2, and 0.099 mg/L, respectively. Piper diagram indicates that groundwater in the study area is SO4·Cl–Na type, SO4·Cl–Ca·Mg type, and HCO3–Na type. Gibbs diagrams suggest that the major ion chemistry of groundwater in the area is governed by rock weathering and water–rock interaction, while evaporation plays a minor role. According to the results of groundwater quality assessment, over one-third (36.67%) of the groundwater samples are of poor or very poor quality. Through oral pathway, female and male adults in the study area face acceptable non-carcinogenic risks, while children face unacceptable non-carcinogenic risks caused by Cr6+ and NO3−. Both children and adults face unacceptable carcinogenic risks from Cr6+. In addition, children face higher carcinogenic risks than females and males owing to smaller body weight than adults. This study may provide local authorities with insights into making scientific decisions for sustainable groundwater exploitation and efficient groundwater environmental protection.

Hydrogeochemical Characteristics, Groundwater Quality, and Health Risks from Hexavalent Chromium and Nitrate in Groundwater of Huanhe Formation in Wuqi County, Northwest China

An assessment of groundwater quality for irrigation and drinking purposes around brick kilns in three districts of Balochistan province, Pakistan, through water quality index and multivariate statistical approaches

Water quality is a big concern for the humankind as it is the most important natural resource. However, the non-controlled growth of rural and urban areas in rapidly developed countries suc...

Assessment of heavy-metal pollution in three different Indian water bodies by combination of multivariate analysis and water pollution indices

Health risk assessment and spatial variations of dissolved heavy metals and metalloids in a tropical river basin system

Water quality assessment in the Bétaré-Oya gold mining area (East-Cameroon): Multivariate Statistical Analysis approach.

To assess the water quality in the locality of Betare-Oya affected by an intensive
artisanal and semi mechanized mining activities, 71 samples were collected
from sixteen points during the 2015-2016 hydrological year. These
points include: three in Lom river which is the main stream of the study area,
five in Mari river which is one of the left bank tributaries of the Lom, in
Betare-Oya and eight in the left and the right bank of Mari. Different physicochemical
parameters such as pH, electrical conductivity (EC), alkalinity,
turbidity, total suspended solids (TSS), cyanide (CN-), major elements and
heavy metals (Pb, Zn, Cd, Fe, Cu, As, Mn and Cr) were analyzed. Water Quality
Indices (WQI), Heavy metal Pollution Index (HPI), sodium adsorption ratio
(SAR) and percent sodium (Na%) were also computed to evaluate the suitability
of water for drinking and irrigation. The results showed that the surface
water from Betare-Oya was acidic to basic (5.40

/pdf/assessment-of-surface-water-quality-of-betare-oya-gold-2eosv5cok1.pdf

Zakari Mfonka

Papers

Water quality assessment in the Bétaré-Oya gold mining area (East-Cameroon): Multivariate Statistical Analysis approach.

Assessment of Surface Water Quality of Bétaré-Oya Gold Mining Area (East-Cameroon)

Spatio-temporal assessing rainfall and dam impacts on surface runoff in the Sanaga river basin (transition tropical zone in central part of Cameroon)

Evaluation and Mapping of Rainfall Erosivity from Tamsat Satellite Data in the Sanaga River Basin (Srb) in Nachtigal, Cameroon (Central Africa)