Enrichment, contamination and geo-accumulation factors for assessing arsenic contamination in sediment of a Tropical Open Lagoon, Southwest Nigeria

Abstract

The presence of toxic heavy metals and metalloids in aquatic environments constitutes a major risk and there is an urgent need for continuous monitoring of such pollutants.This study assesses the concentrations of arsenic (As) in surface sediments from 15 locations on the Lagos Lagoon, Nigeria during the wet and dry seasons to determine the degree of contamination. The results showed that the mean total As concentration in sediment (2.44 mg kg -1 dry weight) did not exceed the Canadian Interim Sediment Quality Guideline (CISQG) value of 7.24 mg kg -1 dry weight during the wet and dry seasons. Based on the Sediment Quality Guidelines (SQGs) of the United States Environmental Protection Agency (USEPA) and ecological risk assessment using the enrichment factor (EF), contamination factor (CF) and geo-accumulation index (Igeo), the study's results indicate two things: firstly, low to moderate and significant levels of enrichment from As; and secondly, low to moderate degree of contamination in Lagos Lagoon during the study period.

Pollution Distribution of Potentially Toxic Elements in a Karstic River Affected by Manganese Mining in Changyang, Western Hubei, Central China

“…Geo-accumulation index (I geo ) is a widely used method to evaluate pollution of PTEs in sediments [ 32 , 33 ]. Its formula is: where Y i is the concentration of potentially toxic element in the sediment (mg·kg −1 ), and B i is the geochemical background concentration of the PTEs in the river sediment (the B i of As = 19, Cd = 1, Cr = 82, Cu = 39, Mn = 487, Pb = 15, Zn = 85 mg·kg −1 ); A is the calibration factor and generally with 1.5; I geo has seven grades ( Table 1 ), interpreting as: I geo ≤ 0—uncontaminated; 0 < I geo ≤ 1—uncontaminated to moderately contaminated; 1 < I geo ≤ 2—moderately contaminated; 2 < I geo ≤ 3—moderately to heavily contaminated; 3 < I geo ≤ 4—heavily contaminated; 4 < I geo ≤ 5—heavily to extremely contaminated; I geo ≥ 5—extremely contaminated [ 32 , 33 , 34 ].…”

“…where Yi is the concentration of potentially toxic element in the sediment (mg•kg −1 ), and Bi is the geochemical background concentration of the PTEs in the river sediment (the Bi of As = 19, Cd = 1, Cr = 82, Cu = 39, Mn = 487, Pb = 15, Zn = 85 mg•kg −1 ); A is the calibration factor and generally with 1.5; Igeo has seven grades (Table 1), interpreting as: Igeo ≤ 0uncontaminated; 0 < Igeo ≤ 1-uncontaminated to moderately contaminated; 1 < Igeo ≤ 2moderately contaminated; 2 < Igeo ≤ 3-moderately to heavily contaminated; 3 < Igeo ≤ 4heavily contaminated; 4 < Igeo ≤ 5-heavily to extremely contaminated; Igeo ≥ 5-extremely contaminated [32][33][34]. To assess the potential ecological risk of PTEs in river sediments, the Hakanson's potential ecological risk (IPER) is used, which indicates the toxicology of PTEs [35][36][37].…”

A Enrichment Factors for Cadmium and Lead in Sediment of Gembong Estuary, Bekasi, Indonesia

“…The presence of heavy metals cadmium and lead in aquatic environments constitutes a major risk and concern with fear, thus it needs for continuous monitoring (Usese et al, 2017). Gembong estuary is mouth of Citarum river that upper course from Wayang mountain.…”

3D Spatial Distribution of Arsenic in an Abandoned Mining Area: A Combined Geophysical and Geochemical Approach

“…A significant number of indicators designed to approximate the quality of soils can be found in the literature. In our case, the assessment of sediment contamination level was performed by the quantification of the contamination factor (CF) and the acid mine drainage mobility indicator [20][21][22][23].…”