Heavy Metal Contamination Index, Metal Index and Polycyclic Aromatic Hydrocarbon Content of Ochani River in Ogoni, Rivers State, Nigeria

Abstract

The Heavy metal Pollution Index (HPI), Metal Index (MI) and the Polycyclic Aromatic Hydrocarbon (PAH) contents of crude oil-polluted Ochani River in Ejamah-Ebubu community were investigated using physicochemical properties, Heavy Metal Analytic Method (AAS), GC-MS method and heavy metal pollution model. The results showed that Ochani River sampling station 2 (ORPS 2) had highest values of temperature, conductivity, turbidity, total solid (TS), total dissolved solid (TDS), Total Suspended Solid (TSS), Dissolved Oxygen (DO), Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD) and nitrates with values as (32oC, 260 µScm-1, 42NTU, 460 mg/L, 526 mg/L, 400 mg/L, 15 mg/L, 10 mg/L, 25 mg/L and 7.5 mg/L respectively) compared to Ochani River sampling station 1 (ORPS 1) with values as (30oC, 200 µScm-1, 38NTU, 400 mg/L, 500 mg/L, 380 mg/L, 13 mg/L, 9.0 mg/L, 22 mg/L and 6.8mg/L respectively). However, these values of ORPS 1and 2 were higher than the unpolluted water sample (UWS) and WHO standard limits. Heavy metals obtained in Ochani River were rankedas Fe > Cu >Pb> Zn > Cr > Cd >As. The values obtained from crude oil polluted water samples were highest when compared with the values obtained of the UWS and WHO standard limit. The heavy metal pollution index of Ochani River was calculated as 402.32 mg/L which was higher compared with the critical pollution index value of 100. The metal index obtained was 49.88mg/L showing that the water quality classified to be seriously polluted. The Polycyclic Aromatic Hydrocarbon (PAH) components present in Ochani River include fluorene, naphthalene, dibenzyl(a,h)anthracene, benzo(k)fluoranthene and benzo(a)pyrene. However, these values of PAH components obtained were highest in ORPS 2 compared to ORPS 1. No PAH content was detected in UWS. However, the values of PAH obtained in both ORPS 1 and 2 were higher compared with WHO standard limit. In conclusion, Ochani River which is an important river used for irrigation and domestic activities by the populace in that community, is highly polluted with heavy metals and carcinogenic PAHs. We therefore recommend that Ochani River is unsafe for drinking, domestic and agricultural activities of the community where it is sited.

Addressing Heavy Metal Pollution in Nigeria: Evaluating Policies, Assessing Impacts, and Enhancing Remediation Strategies

“…International standards for heavy metal pollution and their application in Nigeria have been a topic of concern in several studies. The studies have focused on different aspects of heavy metal pollution, including its effects on water sources, staple food cultivars, drinking water, and soil (Nicholas et al, 2022;Agbaje et al, 2023). The results of these studies have shown that heavy metal concentrations in various environmental samples often exceed the recommended limits set by international standards such as those of the World Health Organization (WHO) and the Standard Organization of Nigeria.…”

“…This indicates a potential health risk to human populations and ecosystems. Overall, research from Nigeria highlights the importance of adhering to international standards to protect human health and the environment from the adverse effects of heavy metal pollution (Adeyeye et al, 2018;Afonne et al, 2022;Essien et al, 2022;Nicholas et al, 2022;Agbaje et al, 2023). International standards for heavy metal pollution also involve conventions, protocols, and agreements aimed at reducing and controlling the release of heavy metals into the environment.…”

Techniques in chitosan extraction from indigenous crab and utilization in bio-filtration of crude oil polluted water

“…The containers were thoroughly washed, sterilized with 70% ethanol, rinsed multiple times with distilled water, and finally with the sample solution before collecting the sample for analysis. The collection of the crude oil-polluted water sample from Ochani River followed the procedure reported by Nwogu et al (2022). The water sample was collected with a 2-liter plastic cup at a depth of 8 -10 cm and then transferred into a 25-liter container with screw cap, labeled appropriately.…”

Comparative studies on exposure of edible vegetables to spent engine oil and PAH components

“…The unrelenting organic pollutant such as polycyclic aromatic hydrocarbons (PAHs) is a hazard that has to be curbed as it has dented every part of the ecosystem. This PAHs are mostly obtained from human endeavors or inherent processes (Hahladakis et al, 2013;Nwogu et al, 2022). The increase in PAH discharge as a consequence of partial incineration from human activities allows its deposition in the soil, which has led to its accumulation in food crop and other biota, and is then transferred to humans through the food chain (Kim et al, 2013).…”

“…These water bodies serve as water sources to the locals occupying the area and it usually provides for activities, such as drinking, farming, etc. (Nwogu et al, 2022).…”