Baseline PAHs, N-PAHs and 210Pb in Segment Samples from Bodo Creek: Comparison with Bonny Estuary, Niger Delta

Abstract

Chemical-surveys of sediments are source of information about historical-pollution in aquatic-ecosystems, because ecological/human-health risks may arise from polycyclic-aromatic-hydrocarbons (PAHs) and nitrogen-PAHs presence in aquatic-environments, particularly sediments, where they partition. Despite this, sediment-PAHs/N-PAHs have not been reported in the Niger Delta. This study investigated vertical-profiles of PAHs/N-PAHs in 2cm-intervals-segments from Bonny Estuary, Niger Delta. Analysis showed that ƩPAHs/ƩN-PAHs in segments ranged from 8699-22528µg/kg and 503-2020µg/kg, respectively. Abundant-PAH/N-PAH are 2,6dimethyl-naphthalene and benzo[a]acridine. PAHs/N-PAHs in the samples appeared to be from petrogenic and pyrogenic-sources. Petrogenic-PAHs/N-PAHs were predominated by 2-, 3-rings, alkylated-substituents, while, pyrogenic-PAHs/N-PAHs were dominated by 4-, 5-, 6-rings. Surface-sediments were dominated by petrogenic-PAHs/N-PAHs while, deeper-cores were heavily-contaminated with pyrogenic-PAHs/N-PAHs. ƩPAHs exceeded the ISQGs and PELs of CSQGs. Ʃ-quinoline/Ʃ-acridine exceeded the guidelines for protection of aquatic-life. Furthermore, there are concerns over toxic-ratios >70% in the estuary. Such surveys may be helpful in future sediment-management-decisions for contaminated-systems and long-term-monitoring of sediments to assess remediation/recovery.

Baseline toxicological assessment of biliary PAHs and heavy metals contamination in a commercially consumed native fish (Mugil cephalus) within Fiji coastal waters

“…Nevertheless, the enzyme cascade between GPX and GR was notably re ected in mullet from both sites based on the levels of pollutants present in the respective environments. Studies show that relatively high levels of organic pollutants like PAHs and essential metals are likely to induce higher levels of oxidative stress responses due to hepatic metabolism and biotransformation e ciency 71,72 . In this study, it was observed that mullet from Ba River Delta, which had more polycyclic aromatic hydrocarbons (PAHs) and chromium (Cr), also had higher levels of biotransformation activities.…”

Pollution of the Niger Delta with total petroleum hydrocarbons, heavy metals and nutrients in relation to seasonal dynamics

“…The Niger Delta region is one of the largest wetland systems worldwide and can be considered a biodiversity hotspot comprising the greatest diversity of aquatic species in Africa 1 – 3 . Several severe anthropogenic pressures exist in this region, increasing the vulnerability of the system by contamination, global environmental change, and a resulting rapid quality decline in the region’s fragile ecosystems 1 – 6 . Contamination has been of major concern in the region due to the associated (eco)toxicity, bioaccumulation, persistence and risks to biota including humans 3 – 6 .…”

“…Several severe anthropogenic pressures exist in this region, increasing the vulnerability of the system by contamination, global environmental change, and a resulting rapid quality decline in the region’s fragile ecosystems 1 – 6 . Contamination has been of major concern in the region due to the associated (eco)toxicity, bioaccumulation, persistence and risks to biota including humans 3 – 6 . Fundamentally, estuarine regions of large river systems are known sinks of contaminated sediments and a source of contamination for the adjacent marine habitats.…”

“…Fundamentally, estuarine regions of large river systems are known sinks of contaminated sediments and a source of contamination for the adjacent marine habitats. Although this situation can be observed in many estuarine regions worldwide 3 , 6 – 9 , the African Niger Delta is an example of how a broad range of unsupervised human activities directly impact contaminant levels. Due to their persistence, some of the contaminants of concern are the total petroleum hydrocarbons (TPHs) and heavy metals (HMs) resulting from the heavy oil exploitation within the Niger Delta system.…”

“…Despite this general understanding, there is no systematic assessment undertaken to relate the occurrence and dynamics of these pollutants in light of changing and extreme climatic conditions. Global warming is not only affecting surface temperature, but will also result in altered salinity gradients, increasing floods and altered hydrological regimes, which can significantly affect contaminant mobilization and distribution and therefore bioavailability 6 , 10 . In contrast, drought events and high evaporation rates can lead to increased concentration of pollutants 11 .…”