scholarly journals Ecological Risk Indicators for Leached Heavy Metals from Coal Ash Generated at a Malaysian Power Plant

2021 ◽  
Vol 13 (18) ◽  
pp. 10222
Author(s):  
Teh Sabariah Binti Abd Manan ◽  
Salmia Beddu ◽  
Nur Liyana Mohd Kamal ◽  
Daud Mohamad ◽  
Zarina Itam ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Ecological Risk ◽  
Risk Index ◽  
Bottom Ash ◽  
Coal Ash ◽  
Risk Indicators ◽  
Risk Indicator ◽  
Model Risk ◽  
Leaching Procedure ◽  
Significant Model

The application of coal ash (CA) in construction industries has grown rapidly, posing risk to the environment due to heavy metals leaching from the material. This research presents a simulation of ecological risk assessment and model risk indicators (ERI) of leached heavy metals (lead (Pb), copper (Cu), zinc (Zn) and arsenic (As)) from CA (FA: fly ash and BA: bottom ash) via response surface methodology (RSM). The ERI values were based on quantified leached heavy metals from the toxicity characteristic leaching procedure (TCLP-1311) and synthetic precipitation leaching procedure (SPLP-1312). The ecological risk index (RI ) values for TCLP were 10.27 × 100 (FA), 9.91 × 100 (BA) and 12.58 × 100 (FA + BA); whereas RI for SPLP were 10.34 × 100 (FA), 9.90 × 100 (BA) and 12.61 × 100 (FA + BA). Twenty-nine combinations of operations were evaluated based on Box-Behnken design with ERI as the response variable. The established model risk indicator (i.e., coded and actual factors) of Pb, Cu, Zn and ‘As’ showed significant model terms that describe their relationship very well, perfectly fit to the corresponding ERI (sum of squares = 0.4160, F value = 682,375.55) with probability of 0.01% for an F-value could occur due to noise. The optimized models were validated with error percentage of less than 5%. The established ERI models showed significant model terms and will be useful for ecological monitoring of CA application in construction industries.

scholarly journals Leachability of Self-Compacting Concrete (SCC) Incorporated with Fly Ash and Bottom Ash by Using Toxicity Characteristic Leaching Procedure (TCLP)

2015 ◽  
Vol 773-774 ◽  
pp. 1271-1275 ◽  
Author(s):  
Aeslina Abdul Kadir ◽  
Mohd Ikhmal Haqeem Hassan ◽  
Eric Cheah Keng Yang
Keyword(s):  
Heavy Metals ◽  
Fly Ash ◽  
Power Plant ◽  
Bottom Ash ◽  
Coal Ash ◽  
Absorption Spectrometry ◽  
Toxicity Characteristic Leaching Procedure ◽  
Self Compacting Concrete ◽  
Concrete Technology ◽  
Leaching Procedure

The process of combustion in coal fired power plant generates ashes, namely fly ash (FA) and bottom ash (BA). In addition, coal ash generated from coal combustion generally contains heavy metals within their compositions. These metals are toxic to the environment as well as to the human health. Fortunately, treatment methods are available for these ashes and the use of FA and BA in concrete mix is one of the few. As such, this study presents the work in determining the leachability of self-compacting concrete (SCC) incorporated with FA and BA. The ashes were obtained from Kapar Energy Ventures power plant in Kapar, Selangor. SCC mixtures incorporated with 10%, 20% and 30% FA (replacing cement) and BA (replacing sand) respectively was formulated and casted. The samples were then crushed to be extracted using Toxicity Characteristic Leaching Procedure (TCLP) and heavy metals content within the samples were identified accordingly using Atomic Absorption Spectrometry (AAS). From the results, it was found that incorporation up to 30% of the ashes were safe as the leached heavy metals concentration did not exceed the regulatory levels, except for arsenic (As). On the other hand, incorporation of 20% FA and BA each in SCC provided the most economically viable product, with high strength and low leachate concentrations. In conclusion, this study will serve as a reference which suggests that FA and BA are widely applicable in concrete technology and its incorporation in SCC constitutes a potential means of adding value with appropriate mix and design.

scholarly journals Assessment of heavy metals contamination and associated risks in shallow groundwater sources from three different residential areas within Ibadan metropolis, southwest Nigeria

2021 ◽  
Vol 11 (5) ◽  
Author(s):  
Saheed Adekunle Ganiyu ◽  
Abimbola Temitope Oyadeyi ◽  
Azeem Adedeji Adeyemi
Keyword(s):  
Heavy Metals ◽  
Cancer Risk ◽  
Urban Area ◽  
Ecological Risk ◽  
Water Samples ◽  
Risk Index ◽  
Shallow Groundwater ◽  
World Health ◽  
Southwest Nigeria ◽  
The Mean

AbstractThis study has been conducted to appraise the concentrations of selected heavy metals and total dissolved solids (TDSs) in the drinking water from shallow wells in parts of Ibadan metropolis, southwest Nigeria. Fifteen (15) water samples were collected from three representative residential locations [traditional core area (TCA), peri-urban area (PUA), and urban area (UA)] for geochemical analysis. Heavy metals and TDS were analyzed with the aid of atomic absorption spectrophotometer and calibrated meter, respectively. The mean concentration (mg/L) of Zn, Pb Mn, Fe, and Cd has been 3.930, 0.658, 0.0304, 1.698, and 0.501, respectively, and as a consequence, the order of abundance of studied metals was Zn > Fe > Pb > Cd > Mn. Concentrations of Zn, Fe, Pb, and Cd were higher than recommended standards in 60%, 86.7%, 100%, and 100% of groundwater samples, respectively. However, at all points tested, the mean concentrations of Mn and TDS in water samples lie within the safe limits set by World Health Organization. The evaluation of geoaccumulation index (Igeo), enrichment factor (EF), and contamination factor suggests that representative water samples were low-to-moderate contamination. The potential ecological risk index advocates low-to-moderate ecological risk in TCA and PUA, while it demonstrated exclusive “moderate” risk in UA. Further, the range of pollution load index (PLI) (0.55–1.32) in both TCA and PUA shows nil-to-moderate pollution status, while PLI values > 1 in UA indicate moderate contaminated state. The degree of contamination in groundwater showed the following trends: UA > TCA > PUA in the study area. Moreover, the results of EF and quantification of contamination of analyzed metals in water samples indicate geogenic and anthropogenic inputs. The contribution of studied metals to the incidence of non-cancer risk via oral intake within the residential sites follows the order: cadmium > lead > zinc > iron > manganese. The hazard index as a result of ingested heavy metals for the three population classes surpasses the acceptable range in the order of infant < child < adult. Cadmium and lead made considerable impact to the estimation of cancer risk in the study area for the three human population categories. Factor analysis extracted only one component that explained 94.64% of the entire variance, while cluster analysis identified three distinct groups based on similar water quality characteristics. Based on the findings of the study, awareness programs toward protecting the shallow groundwater sources should be launched, encouraged, and sustained. Moreover, the study suggests better hygienic practices and pre-treatment of contaminated water before consumption.

scholarly journals Evaluating ecological risks and tracking potential factors influencing heavy metals in sediments in an urban river

2021 ◽  
Vol 33 (1) ◽  
Author(s):  
Dongping Liu ◽  
Jian Wang ◽  
Huibin Yu ◽  
Hongjie Gao ◽  
Weining Xu
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Ecological Risk ◽  
Metal Pollution ◽  
Heavy Metal Pollution ◽  
Risk Index ◽  
Urban River ◽  
Ecological Risks ◽  
Background Values ◽  
Potential Factors

Abstract Background Heavy metal pollution of aquatic systems is a global issue that has received considerable attention. Canonical correlation analysis (CCA), principal component analysis (PCA), and potential ecological risk index (PERI) have been applied to heavy metal data to trace potential factors, identify regional differences, and evaluate ecological risks. Sediment cores of 200 cm in depth were taken using a drilling platform at 10 sampling sites along the Xihe River, an urban river located in western Shenyang City, China. Then they were divided into 10 layers (20 cm each layer). The concentrations of the As, Cd, Cr, Cu, Hg, Ni, Pb and Zn were measured for each layer. Eight heavy metals, namely Pb, Zn, As, Cd, Cr, Cu, Ni, and Hg, were measured for each layer in this study. Results The average concentrations of the As, Cd, Cu, Hg, and Zn were significantly higher than their background values in soils in the region, and mainly gathered at 0–120 cm in depth in the upstream, 0–60 cm in the midstream, and 0–20 cm downstream. This indicated that these heavy metals were derived from the upstream areas where a large quantity of effluents from the wastewater treatment plants enter the river. Ni, Pb, and Cr were close or slightly higher than their background values. The decreasing order of the average concentration of Cd was upstream > midstream > downstream, so were Cr, Cu, Ni and Zn. The highest concentration of As was midstream, followed by upstream and then downstream, which was different to Cd. The potential factors of heavy metal pollution were Cd, Cu, Hg, Zn, and As, especially Cd and Hg with the high ecological risks. The ecological risk levels of all heavy metals were much higher in the upstream than the midstream and downstream. Conclusions Industrial discharge was the dominant source for eight heavy metals in the surveyed area, and rural domestic sewage has a stronger influence on the Hg pollution than industrial pollutants. These findings indicate that effective management strategies for sewage discharge should be developed to protect the environmental quality of urban rivers.

scholarly journals Assessment of Heavy Metal Pollution Levels in Sediments and of Ecological Risk by Quality Indices, Applying a Case Study: The Lower Danube River, Romania

Water ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 1801
Author(s):  
Valentina Andreea Calmuc ◽  
Madalina Calmuc ◽  
Maxim Arseni ◽  
Catalina Maria Topa ◽  
Mihaela Timofti ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Ecological Risk ◽  
Metal Pollution ◽  
Heavy Metal Pollution ◽  
Surface Sediments ◽  
Risk Index ◽  
Potential Ecological Risk ◽  
Danube River ◽  
Pollution Indices

It is a well–known fact that heavy metal pollution in sediments causes serious problems not only in the Danube basin, but also in the large and small adjacent river streams. A suitable method for assessing the level of heavy metals and their toxicity in sediments is the calculation of pollution indices. The present research aims to assess heavy metal pollution in the Lower Danube surface sediments collected along the Danube course (between 180 and 60 km) up to the point where the Danube River flows into the Danube Delta Biosphere Reserve (a United Nations Educational, Scientific and Cultural Organization – UNESCO, protected area). In addition, this monitored area is one of the largest European hydrographic basins. Five heavy metals (Cd, Ni, Zn, Pb, Cu) were analyzed in two different seasons, i.e., the autumn of 2018 and the spring of 2019, using the Inductively Coupled Plasma Mass Spectrometry (ICP– MS) technique. Our assessment of heavy metal pollution revealed two correlated aspects: 1. a determination of the potential risks of heavy metals in sediments by calculating the Potential Ecological Risk Index (RI), and 2. an evaluation of the influence of anthropogenic activities on the level of heavy metal contamination in the surface sediments, using three specific pollution indices, namely, the Geo–Accumulation Index (Igeo), the Contamination Factor (CF), and the Pollution Load Index (PLI). The results of this pioneering research activity in the region highlighted the presence of moderate metal (Ni and Cd) pollution and a low potential ecological risk for the aquatic environment.

scholarly journals Reforestation Impacted Soil Heavy Metal Fractionation and Related Risk Assessment in the Karst Area, Southwest China

Forests ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 891
Author(s):  
Qian Zhang ◽  
Guilin Han ◽  
Xingliang Xu
Keyword(s):  
Heavy Metals ◽  
Risk Assessment ◽  
Ecological Risk ◽  
Southwest China ◽  
Risk Index ◽  
Contamination Factor ◽  
Karst Area ◽  
Risk Assessment Code ◽  
Bcr Sequential Extraction ◽  
Soil Heavy Metals

Human agricultural activities have resulted in widespread land degradation and soil contamination in the karst areas. However, the effects of reforestation after agricultural abandonment on the mobility risks and contamination of heavy metals have been rarely reported. In the present study, six soil profiles were selected from cropland and abandoned cropland with reforestation in the Puding karst regions of Southwest China. The Community Bureau of Reference (BCR) sequential extraction method was used to evaluate the compositions of different chemical fractions of soil heavy metals, including Fe, Mn, Cr, Zn, Ni, and Cd. The total contents of Cr, Ni, Zn, Cd, and Mn in the croplands were significantly higher than those in the abandoned croplands. For all soils, Cr, Ni, Zn, and Fe were mainly concentrated in the residual fractions (>85%), whereas Mn and Cd were mostly observed in the non-residual fractions (>65%). The non-residual fractions of Cd, Cr, Ni, and Zn in the croplands were higher than those in the abandoned croplands. These results indicated that the content and mobility of soil heavy metals decreased after reforestation. The individual contamination factor (ICF) and risk assessment code (RAC) showed that Cd contributed to considerable contamination of karst soils. The global contamination factor (GCF) and potential ecological risk index (RI) suggested low contamination and ecological risk of the investigated heavy metals in the croplands, moreover they can be further reduced after reforestation.

Precipitation of heavy metals from coal ash leachate using biogenic hydrogen sulfide generated from FGD gypsum

2013 ◽  
Vol 67 (2) ◽  
pp. 311-318 ◽  
Author(s):  
Madawala Liyanage Duminda Jayaranjan ◽  
Ajit P. Annachhatre
Keyword(s):  
Heavy Metals ◽  
Hydrogen Sulfide ◽  
Sulfate Reduction ◽  
Bottom Ash ◽  
Coal Ash ◽  
Reduction Process ◽  
Fgd Gypsum ◽  
Sulfate Reducing ◽  
Sulfate Reduction Process ◽  
Biological Sulfate Reduction

Investigations were undertaken to utilize flue gas desulfurization (FGD) gypsum for the treatment of leachate from the coal ash (CA) dump sites. Bench-scale investigations consisted of three main steps namely hydrogen sulfide (H2S) production by sulfate reducing bacteria (SRB) using sulfate from solubilized FGD gypsum as the electron acceptor, followed by leaching of heavy metals (HMs) from coal bottom ash (CBA) and subsequent precipitation of HMs using biologically produced sulfide. Leaching tests of CBA carried out at acidic pH revealed the existence of several HMs such as Cd, Cr, Hg, Pb, Mn, Cu, Ni and Zn. Molasses was used as the electron donor for the biological sulfate reduction (BSR) process which produced sulfide rich effluent with concentration up to 150 mg/L. Sulfide rich effluent from the sulfate reduction process was used to precipitate HMs as metal sulfides from CBA leachate. HM removal in the range from 40 to 100% was obtained through sulfide precipitation.

scholarly journals GEOCHEMISTRY AND ENVIRONMENTAL ASSESSMENT OF HEAVY METALS IN SURFACE SOIL IN AL-HAWIJA, SOUTHWEST KIRKUK

2020 ◽  
Vol 53 (2E) ◽  
pp. 36-61
Author(s):  
Ahmed Al-Obeidi
Keyword(s):  
Heavy Metals ◽  
Soil Pollution ◽  
Ecological Risk ◽  
Inductively Coupled Plasma ◽  
Surface Soil ◽  
Risk Index ◽  
Size Fraction ◽  
Contamination Factor ◽  
Pollution Load Index ◽  
Anthropogenic Sources

Soil pollution adversely affects the safety and health of the human being. The main objective of the study is to determine the concentrations of heavy metals (As, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb and Zn) in surface soil in Al-Hawija, southwestern Kirkuk. Twenty-one samples were collected and analyzed by inductively coupled plasma-mass spectrometry (ICP-MS) to measure the content of heavy metals and assess the soil pollution by using the contamination factor, degree of contamination, geoaccumulation index, pollution load index and ecological risk index (RI). The results indicate that there is high pollution by lead, chromium and copper (78.8, 87.4 and 53.8 mg/kg) respectively, in industrial areas due to anthropogenic sources with the presence of significant ecological risk (Er) of the lead (116) in site S7, due to its high concentrations, while size fraction analysis indicated that all heavy metals are concentrated in the fine parts as a result of adsorption processes by clay minerals.

scholarly journals Migration and transformation of heavy metals during the microwave-assisted thermal hydrolysis of sewage sludge

2021 ◽  
Author(s):  
Chunsheng Qiu ◽  
Jinxin Zheng ◽  
Chenchen Wang ◽  
Bingbing Wang ◽  
Nannan Liu ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Sewage Sludge ◽  
Ecological Risk ◽  
Risk Index ◽  
Oxygen Demand ◽  
Microwave Treatment ◽  
Potential Ecological Risk ◽  
Ammonium Nitrogen ◽  
Thermal Hydrolysis ◽  
Microwave Assisted

Abstract The migration, transformation and ecological risk of heavy metals (Cr, As, Ni, Cu, Zn, Cd and Pb) in the sewage sludge during the microwave-assisted thermal hydrolysis process were investigated under different temperatures (80 °C, 100 °C, 120 °C, 140 °C, and 160 °C). The potential relationship between the bio-availability of heavy metals and the variables of microwave treatment, including pH, ammonium-nitrogen, soluble chemical oxygen demand, pH, soluble protein, soluble polysaccharide and volatile solid, was also explored. The results showed that the migration of heavy metals between solid-liquid phase mainly depended on the temperature. The percentage of all heavy metals (except Cu) in mobile (acid-soluble/exchangeable and reducible) forms decreased after microwave-assisted thermal hydrolysis treatment. The solubilization of compounds with C = O and O-H accompanied with the generation of organic and inorganic metal halides were also observed in the treated sludge through fourier transform infrared spectroscopy analysis. NH4+-N showed the highest negative correlation to the bio-availability of most heavy metals (except Cu and Cr) with coefficients (absolute value) over 0.87 (P &lt; 0.05). VS showed a positive correlation to the bio-availability of most heavy metals (except Cu). The total potential ecological risk index (RI) decreased by 46.65% after microwave treatment at 160 °C.

scholarly journals Comparison of the Ecological Risk Index of Heavy Metals in the North of Persian Gulf: Hormozgan and Bushehr Provinces

2017 ◽  
Vol 8 (30) ◽  
pp. 37-45
Author(s):  
Mehri Rezaei ◽  
Ali Mehdinia ◽  
Abolfazl Saleh ◽  
Soroush Modabberi
Keyword(s):  
Heavy Metals ◽  
Ecological Risk ◽  
Persian Gulf ◽  
Risk Index ◽  
Ecological Risk Index ◽  
The North

Distribution and Contamination Acessment of Heavy Metals in Sediments of Harbin Section of Songhua River, China

2014 ◽  
Vol 955-959 ◽  
pp. 2280-2284
Author(s):  
Kai Yue Gong ◽  
Pei Shi Qi ◽  
Yun Zhi Liu
Keyword(s):  
Heavy Metals ◽  
Ecological Risk ◽  
Risk Index ◽  
Potential Ecological Risk ◽  
Risk Level ◽  
Index Method ◽  
Songhua River ◽  
Ecological Risk Index ◽  
Risk Levels ◽  
Accumulation Index

In this study, the distribution and enrichment characters of heavy metals were explored. And the potential ecological risk levels of heavy metals were evaluated by geo-accumulation index method and potential ecological risk index method. The concentrations of heavy metals in sediments of Harbin section of Songhua River are: Zn>Pb>Cr>Cu>Ni>Cd. The enrichment degree of Zn is the highest, while Cd is the lowest. The potential ecological risk indexes of heavy metals in the sediments of section of Songhua River in Harbin are: Cd>Pb>Cu>Zn>Ni>Cr. The main heavy metals pollution is Cd, which has low content but considerable potential ecological risk and contributes most to RI. The ecological risk level of heavy metals in the sediments of the section of Songhua River in Harbin is moderate.

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