Levels, Sources, and Risk Assessment of Polychlorinated Biphenyls (PCBs) in Soils from Industrial Areas: A Case Study from Saudi Arabia

ABSTRACT

The objective of this study was to assess the pollution levels, sources, and human health risk of polychlorinated biphenyls (PCBs) in soils of industrial areas of the central and eastern regions of Saudi Arabia. Therefore, the surface soil samples from industrial areas (cement kiln, oil refinery, electric power plant, steel industry, and desalination plant) were collected and analyzed by High-Resolution Gas Chromatography-Mass Spectrometry/Mass Spectrometry-Time of Flight (HRGC-MS/MS-TOF) to quantify the levels of 26 PCBs (including 12 dioxin-like PCBs and 14 indicator-PCBs). The investigated 26 PCBs were detected in all soil samples. The total PCBs concentration (from tri-CBs to hepta-CBs) ranged from 171 to 4892 pg g⁻¹ with an average of 1369 pg g⁻¹ in soils of the central region and of 142–1231 pg g⁻¹ with an average of 302 in soils of the eastern region, showing higher values at cement factory and/or oil refinery sites. Overall, the indicator-PCBs were the main congeners and contributed dominantly to the total mass of PCBs in comparison with the dioxin-like PCB congeners, with the most abundant for PCB-180 in the soil samples of the central region. Among individual dioxin-like PCBs, PCB-126 had the highest average value of the toxicity equivalence (TEQ). The TEQ values of ∑12dioxin-like PCBs did not exceed the Canadian soil quality guidelines of dioxin (4 pg TEQ g⁻¹). Based on human health risk assessment via ingestion, dermal contact, and inhalation, low adverse effects of PCBs could be expected as indicated by lower values of cancer risk (≤10⁻⁶). The principal component analysis indicated that there is a different source of PCBs with similar or different PCB profiles.

KEY WORDS:

• Cancer risk
• dioxin-like PCBs
• indicator PCBs
• industrial activities
• PCBs
• toxic equivalency

Funding

This research was financially supported by the National Plan of Science and Technology (NPST) of Saudi Arabia (Project No. 11-ENV-1590-2), King Saud University, Saudi Arabia.

ORCID

Mohammad I. Al-Wabel http://orcid.org/0000-0002-6223-2953

Adel R. A. Usman http://orcid.org/0000-0001-8522-713X

Aarif H. El-Mubarak http://orcid.org/0000-0002-3940-2061