Evaluation of Polychlorinated biphenyls (PCBs) Concentration Levels in Artisanal Refineries Sites in Delta State

Abstract

Polychlorinated biphenyls (PCBs) are persistent organic pollutants with toxic chemicals that significantly causes harm to human-health and poses risks to the environment. Artisanal refineries, often operates illegally and without proper environmental regulations; in Delta state, are a major source of pollution in the region. Soil surface samples were collected from three different stations, Ekpemu1, Ekpemu2 and Ekpogbene communities. A GC-MS model Agilent 6890, Chromatography was used to determine PCBs levels, the soils from artisanal refinery sites, revealed significant contamination. Most congeners in the data shows considerable variations in PCBs concentration levels. The wide range of PCBs congeners present, with particularly high levels of certain compounds such as, PCB-169 consistently emerges as the most prevalent, with a mean concentration of 171.837, -PCB-81, PCB-66, PCB-105, and PCB-101 followed, with high concentrations value of (154.659, 135.931, 133.968, and 121.237 respectively. Were as the lowest concentrations, found with low mean values are PCB-52 (4.456), PCB-77 (4.886), and PCB-18 (5.814). The ANOVA results suggest, significant differences in PCBs levels between sites, which could lead to varying levels of risk for organisms depending on their specific habitat within the ecological zone. The overall, consistent presence of PCB-169 across all sampled sites, with significant variations between different PCBs congeners with high correlations between sites; as evidenced in the correlation value of (>0.99) which suggest that exposure risks may be widespread in the area and this contamination could lead to long-term ecological impacts, including changes in species composition, reduced biodiversity, and altered ecosystem functions. Appropriate remediation methods and enforcement of already existing policies for sustainable development and pollution control should be more enacted in Delta State. The majority of the time, polychlorinated biphenyls (PCBs) are released into the environment as unintentional byproducts of industrial processes such as chemical production, metal smelting, and incineration. The persistent organic compounds known as PCBs are present in soils and dust (Harrad et al., 1994), water (Nie et al., 2005), river and underwater debris (Roose et al., 2005, Covaci et al., 2005), vegetative life (Schuhmacher et al., 2004), air (Sun et al., 2006), and other "biota" (naturally occurring things, as-well-as individuals and wildlife) that exist (Riget et al., 2004, Miao et al., 2000). Prior to the 20th century, PCBs were discharged into the air, water, and land as a result of production, usage, elimination, accidental spills, transportation leaks, fires, and product leakage. They are extremely steadfast and have a long lifespan in our surroundings. According to Jones and de Voogt (2016), improper municipal waste disposal and agricultural activities like the use of pesticides and herbicides can also release harmful pollutants. According to Li et al. (2018) and Okkels et al. (2021), surface soils are a significant source of PCBs due to their ability to bind these compounds to organic molecules and soil granules. The stability of various PCBs varies. Eating certain animal and plant species is the main way that people are exposed to PCBs. They are man-made and are not often found in the environment. Hydraulic fluids, lubricants, flame retardants, inks, electrical capacitors and transformers, and surface coatings are just a few of the many products that include PCBs, a group of 209 corresponding substances. Large volumes of PCBs pollutants are released into the environment, creating major pollutants and damaging ecosystems. These substances are typically chlorinated, naturally occurring pollutants (Zhang et al., 2018). They are one of 12 categories of persistent organic compounds that need to be regulated by the UNEP because of their severe effects on health, bioaccumulative nature, unpredictability, and persistence. The physical and chemical properties of polychlorinated biphenyls (PCBs) are surprisingly stable. Because of their hydrophobic and lipophilic characteristics, extended build-up times, and widespread natural buildup of congeners with identical blueprints, PCBs have a half-life of around 40 years and are very difficult to break down once they reach the surrounding environment. Following their introduction into the environment, PCBs concentrate in living organisms are gradually increasing in abundance across the food chain. According to Fiandanese et al. (2016), the burning of fuel, the production of cement, the paper and pulp industries, and petroleum-related firms that release smelted ferrous and non-ferrous metals into the ecosystem are all potential sources of dioxin-like compounds. Lesser non-point causes include household biomass burning, dumpsite fires, and natural occurrences like bush fires and unapproved burning (UNEP 2005). They are widely dispersed across the earth’s environments and are resistant to biological, chemical, and physical changes (De Boer et al. 2000; Alison and Jason 2008). Rivers and other bodies of water in many countries still contain these contaminants, even if they are no longer manufactured (Barra et al. 2005; Neamtu et al. 2009). According to Okkels et al. (2021), surface soils are a significant PCBs storage media due to their ability to attach to organic molecules and soil grains. Nevertheless, since PCBs do not readily break down in the environment, they can be released into environments by the combustion of certain materials in incinerators, the illegal or inappropriate dumping of consumer goods and industrial waste, or hazardous waste containers. Because of this, PCBs that are released form strong bonds with soil, organic matter, and bottom sediments. PCBs can dissolve in water at lower concentrations even though they like to stick to soil alongside other particles. Furthermore, PCBs have the potential to disperse and travel incredibly far via the atmosphere even in little amounts. United Nations Environment Programme (UNEP) 2005.