Heavy metals contamination of seafood from the crude oil-impacted Niger Delta Region of Nigeria: A systematic review and meta-analysis.

This study aims at computing the pooled mean estimate (PME) and health risks of heavy metals in seafood obtained from the Niger Delta Region of Nigeria (NDRN), using data from existing literatures. Pubmed, Scopus and Google Scholar were searched to retrieve articles that investigated the heavy metal contents of edible seafood from the NDRN. Search hits were screened against predetermined criteria following which relevant data were extracted from eligible articles. The PME for each metal was computed by performing a maximum likelihood random effect model meta-analysis using the R Studio Software. Outcome from the meta-analysis involving 58 studies and a total of 2983 seafood samples revealed the following PMEs (mg/kg dry wt seafood) for the investigated heavy metals: As (0.777), Cd (0.985), Co (4.039), Cr (2.26), Cu (11.45), Fe (143.39), Hg (0.0058), Mn (13.56), Ni (5.26), Pb (4.35), and Zn (29.32). The health risk assessment suggests that seafood from this region poses considerable carcinogenic and non-carcinogenic risks to human consumers. Our finding calls for urgent actions aimed at identifying and eliminating point sources of heavy metals pollution of the NDRN marine environment. Inhabitants of NDRN are encouraged to reduce seafood consumption while diversifying their protein sources to include non-seafood options.

Macroporous adsorptive resin-assisted enrichment of polyphenol from Psidium guajava leaves improved its in vitro antioxidant and anti-hemolytic properties.

Phytochemical analyses of guava leaf extracts, commonly applied in traditional medicine, revealed the presence of several bioactive polyphenols. In this study, we optimized the enrichment of total polyphenol from Guava leaf ethanolic extract (GEE) using six macroporous adsorptive resins (MAR) including AB8, D101, X5, ADS17, S400, and AD7. Also investigated are the contributions of adsorption time, extract concentration, pH, elution time, and eluent ethanol concentrations on the polyphenol enrichment potential of MAR. The antioxidant and anti-hemolytic properties of the crude and polyphenol-rich extracts were determined. Our results indicate that treatment of GEE extract with AB8 MAR at a concentration of 15 mg GEE/g resin, adsorption time of 45 min, elution time of 40 min, and eluent ethanol concentration of 50% (v/v) improved the flavonoids and phenol concentration of GEE by 2 and 2.5 folds respectively. The DPPH radical scavenging, ferric reducing ability of the plasma (FRAP), anti-hemolytic and anti-peroxidation activity of the resultant polyphenol-rich extracts improved by 1.5, 1.6, 1.4, and 1.88 folds respectively, when compared to the crude extract. Our work shows that the MAR-assisted enrichment operation is a rapid, feasible, and economical strategy for enriching bioactive polyphenols from guava leaf extracts.

Heavy metal profile of surface and ground water samples from the Niger Delta region of Nigeria: a systematic review and meta-analysis.

This systematic review and meta-analysis estimated the pooled mean levels of heavy metals in ground and surface water samples obtained from the Niger Delta region of Nigeria (NDRN). PUBMED and Google Scholar databases were searched for studies published between 2000 and 2019, which assessed the levels of heavy metals in natural water samples obtained from the NDRN. Thirty one (31) studies which had a total of 951 water samples were identified. The pooled mean estimate (PME) from the meta-analysis indicates that the levels of Ni, Cd, Cr, and Pb in the majority of the natural water bodies from the NDRN are higher than the WHO safe permissible limit for drinking water. The contributions of prevailing anthropogenic activities to the observed heavy metal profiles of natural water sources from the NDRN were discussed. Stricter enforcement of safe environmental practices is necessary to protect the lives of the over 30 million inhabitants of this oil rich region.