Concentrations of Heavy Metals in Six Municipal Sludges from Guangzhou and Their Potential Ecological Risk Assessment for Agricultural Land Use

Heavy metals pollution is a worldwide problem that has grown during the past few decades because of their toxicity, extensive sources, non-biodegradable characteristics, and accumulative behaviors in aquatic environments [1][2][3]. These metals are identified as a significant indicator for degradation of aquatic environments. Enormous quantities of metals are being released into the environment both from anthropogenicrelated processes and natural sources through direct discharge into water or indirectly through stormwater runoff, domestic effluents, fossil fuel combustion, and atmospheric depositions [4]. Heavy metals ultimately Pol. J. Environ. Stud. Vol. 27, No. 2 (2018), 675-688 Original Research Heavy Metals Contamination and Ecological Risk AbstractHeavy metal concentrations were determined using inductively coupled plasma-optical emission spectrometry (ICP-OES) in surface sediments of Namal Lake, Pakistan. The metals content in sediment varied significantly and were in the order of Al>Fe>Mn>V>Zn>Cr>Ni>Cu>As>Co>Pb>Cd. Except for Al, the average concentrations of metals were higher than the average value of the upper continental crust (UCC). The significant positive correlations among heavy metals (p<0.01) suggested that these metals originated from the same sources. The pollution indices indicated severe contamination of sediments with As, Cd, and Ni. The sediment quality guidelines (SQGs) revealed that 19.2% of As, 11.5% of Cr, and 88.5% of Ni from all the sampling sites exceeded the probable effect level (PEL). The computed average risk index (RI) of single elements were in the following order Cd(411.9)>As(69.0)>Ni(15.4)>Cu(10.0)>Cr(4.3)> Pb(3.66)>Zn(1.7). Principle component analysis (PCA) extracted three components explaining (76.136%) of total variance of chemical data and were highly to moderately loaded with Fe, Mn, Co, Cu, Zn, Al, As, Cd, Ni, V, Cr, TOC, pH, CaCO 3 , and Pb in three principal components (PCs). The results obtained from cluster analysis, correlation of heavy metals, and principal component analysis suggested the origin of metals from both anthropogenic and natural sources.

Section: Potential Ecological Risk Indexmentioning

confidence: 99%

Heavy Metals Contamination and Ecological Risk Assessment in Surface Sediments of Namal Lake, Pakistan

Javed¹,

Ahmad²,

Mashiatullah³

2018

“…RI is the comprehensive potential ecological index, which is the sum of individual heavy metals -E i . It represents the sensitivity of the biological community to the toxic substance and illustrates the potential ecological risk caused by the overall contamination [20]. The RI was calculated as the sum of risk factors of the heavy metals: (4) …where E i is the single risk factor for heavy metal i, and is defined as: (5) …where T i is the toxic response factor for heavy metal i.…”

Section: Ecological Risk Factormentioning

confidence: 99%

“…Many calculation methods have been proposed by authors for evaluating heavy metal pollution in soils and sediments. The most widely used methods are calculations of single pollution index (PI i ), enrichment factor (EF), geoaccumulation index (Igeo), Nemerow pollution index (PI N ), and potential ecological risk index (RI) [17][18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Assessing the Anthropogenic Impact on Heavy Metal Pollution of Soils and Sediments in Urban Areas of Azerbaijan’s Oil Industrial Region

Khalilova¹,

Mammadov²

2016

This paper presents the result of studies of heavy metal pollution in soils and sediments caused by various anthropogenic sources to assess the environmental impact of human activities in the major industrial region of Azerbaijan, the Absheron peninsula. Soil and sediment samples were analyzed for As, Cd, Hg, Pb, Cr, Cu, and Zn using inductively coupled plasma-optical emission spectrometry (ICP-OES) and cold vapor atomic fluorescence (CVAF) methods. The results of analyses showed that the main concentrations of such toxic metals as Hg, Cd, and Pb were 0.1, 2.40, and 302 mg/kg in the soil samples, and 0.028, 2.7, and 29 mg/kg in the sediment samples, respectively. These values are several times higher than the standards established by the Azerbaijani Cabinet of Ministers for the Absheron soils. The highest concentrations of metals were found in soils from the area of a highway and in the sediments of the largest natural lake of the peninsula, Boyuk, whose shores are subjected predominantly to oil industry's wastewater. The pollution index (PI), enrichment factor (EF), geoaccumulation index (I geo ), and ecological risk factor (E i ) were calculated to assess the level and potential ecological risk of heavy metal pollution. Analysis of the calculated values of PI, EF, I geo , and E i indicate the contribution of anthropogenic sources to heavy metal accumulation in the soils and sediments of the study area.

“…Sludge originating from wastewater treatment is frequently spread on land to restore degraded soils [6]. Wastewater sludge has a high organic matter content and is rich in nutrients, e.g., mainly nitrogen and phosphorous, stimulating plant growth.…”

Section: Introductionmentioning

confidence: 99%

Dissipation of Phenanthrene and Anthracene from Soil with Increasing Salt Content Amended with Wastewater Sludge

Fernández-Luqueño

Cabrera-Lazaro

Corlay-Chee

et al. 2017

The removal of PAHs was stimulated by wastewater sludge in an alkaline saline soil of the former Lake Texcoco, but not always to the same extent. We investigated how a varying electrolytic conductivity (EC) affected the removal of phenanthrene (PHEN) and anthracene (ANTHR) from wastewater sludge-amended soils. Soil with EC 6, 30, 80, and 146 dS m -1 was contaminated with PHEN and ANTHR and amended with or without wastewater sludge, while emissions of CO 2 and concentrations of ammonium, nitrite, and nitrate were monitored. A decrement on the concentrations of PHEN and ANTHR was observed and was faster in soil with EC 6 dS m -1 than in soil with EC 30 dS m -1 and 80 dS m -1, and was slower than in soil with EC 146 dS m -1 . Adding wastewater sludge to soil reduced the concentration of PHEN and ANTHR in soil after 56 days. Spiking soil with PAHs or amending it with wastewater sludge increased the CO 2 emission rate, but decreased at higher EC. The concentration of NO 3 -decreased when soil was spiked with PAHs and amended with sludge, except in soil with EC 146 dS m -1. It was found that the removal of PAHs was not inhibited by salt content and a principal component analysis indicated that none of the measured soil characteristics, i.e., pH, EC, particle size distribution, water-holding capacity, or organic C content predicted the removal of ANTHR or PHEN from contaminated soil. The application of wastewater sludge increased the dissipation of PHEN and ANTHR after 56 days.