Determination of Heavy Metals in Soil Samples in the Vicinity of Liquid Natural Gas Project, Shabwah Governorate, Yemen

Khaled Laqal; Siddig Tawaer Kafi; Yousef. A. Alsabah; Abobakr. A. M. Salem; Abdelsakhi Suliman

Abstract

The present work aimed to determine the contaminants in soils resulting from or deposited due to emissions that come from natural gas in the area of Balhaf which is an LNG project in Republic of Yemen. Total of 8 surface soil samples were collected at depth of approximately (0–10 cm) from two sites which has different distances from the natural gas liquefaction project, took 4 samples from first site. The distances from the project center was approximately 3.5 km. 4 samples from second site have the distance from the project center of approximately 5 km. These samples were analyzed by Fourier Transform Infrared (FTIR) to determine toxic elements in the samples. The components of the toxic elements present in the soil samples were further confirmed by spectroscopic technique Induced Coupled Plasma (ICP). The FTIR spectrum indicated that most common functional groups in all samples were: secondary amide N–H, nitrate NO2 bending, C–O stretching, alcohols and phenols, C–O stretching, alcohols and phenols and C–O–H in-plane bending, carboxylic acids. These functional groups may facilitate heavy metal binding on the soil samples. The heavy metals that appeared by ICP were (Al, Ba, Cd, Co, Cr, Cu, Mn, Ni, Th, Tl, Zn). When comparing the concentrations of elements in the five sites, it ranged between 410 ppb and 66 ppb for Al, 1.9 ppb and 0.42 ppb for Ba, 2.6 ppb and 0.92 ppb for Cd, 2.7 ppb and 0 for Co, 2.3 ppb and 0 ppb for Cr, 57 ppb and 18 ppb for Cu, 30 ppb and 2.9 ppb for Mn, 6.8 ppb and 0 for Ni, 63 ppb and 12 ppb for Th, 56 ppb and 19 ppb for Tl and 6.1 ppb and 2.5 ppb for Zn according to the distance from the central location, but these values did not exceed normal levels for these elements in earth crust according to reference values such as ATSDR 2020, IAEA, 200. A high toxic element concentration in the earth soil near the natural gas facility refers to the emissions from this facility that leads to the accumulation of these elements in the area.