Occurrences, distribution of PCBs in urban soil and management of old transformers dumpsite in Addis Ababa, Ethiopia

• Main Authors: Sisay Abebe Debela, Ishmail Sheriff, Jian Wu, Qianwen Hua, Yuan Zhang, Abera Kinfu Dibaba
• Format: Article
• Language: English
• Published: Elsevier 2020-07-01
• Series: Scientific African
• Subjects: Polychlorinated biphenyls (PCBs); Soil; Occurrence; Distribution; Ethiopia
• Online Access: http://www.sciencedirect.com/science/article/pii/S2468227620300673

Polychlorinated Biphenyls (PCBs) are Persistent toxic substances with a high potential to accumulate in soil as organic pollutant and bioaccumulate in human tissues. In the current study, conducted in 2019, 45 composites (0–20 cm) soil samples were collected from 9 sampling sites that are situated in an area that is being used as a maintenance workshop and dump site of transformers in Addis Ababa, Ethiopia. The extraction and cleanup of samples was done using Accelerated Solvent Extraction (ASE) with Pressurized Liquid extraction (PLE). The analysis was done using GC/MS to determine levels and distribution of PCBs, and a checklist was used to assess existing management practice of the site. The data were analyzed by SPSS version 20 and Origin pro 9.1. The result of the 18∑PCBs concentration is 17.16 mg kg−1. The range (in dry weight) of 18∑PCBs, Dioxin-Like (DL) 12∑PCBs, and Non Dioxin-Like (NDL) 6∑PCBs, is 1.027 to 4.862; 0.561 to 1.603; and 0.166 – 4.5 mg kg−1 respectively. The most dominant congeners are lower chlorinated PCBs. The distribution of total PCBs concentrations was found to be different in the entire sample tested but with a similar congener's pattern. Transformers and capacitors were observed to be improperly dumped in open fields, a condition that directly exposed them to the severity of rain and sunlight. The Soil surface around the transformer area had cracks, and literally burnt which is an indication of the degree of pollution of the soil. There is poor management in handling of oil and equipment containing PCBs. It was observed oil was leaking from transformers and barrel, and oil tankers to the open space which may cause leachate. It is important that projects are initiated to remediate the soil in the area to ensure a healthy and sustainable future for all. It will be necessary to organize training programmes for workers at the sites on the safe handling and disposal of PCB related materials.