Recently, there has been a significant increase in the rate and amount of pollutant discharge into the environment. This is extremely worrisome to the human population, especially as it is envisaged to reach 10 billion in the next 40 years. The traditional methods applied for pollutant abatement and recycling exhibit inefficiency and environmental unfriendliness because they cannot effectively transform these pollutants into non-noxious states. Recently, microorganisms and nano-based materials are emerging as highly efficient and eco-friendly alternatives for managing, reducing, and decontaminating pollutant wastes or effluents in the environment. The biosynthesis of these materials has motivated research into developing cheaper, green, and more sustainable yeast, algae, fungi, and bacteria-biogenic nanoparticles, which could be used to clean up heavily contaminated environments. This review evaluates the application of microorganisms (yeast, algae, fungi, and bacteria) with nanomaterials as biogenic nanoparticles to clean up environmental pollutants. The environmental and health hazards associated with the fate of the biogenic nanoparticles, and some legal regulations, are also highlighted. The commercialization of nanomaterials and their possible global application are also documented. Future recommendations were proffered.

This study investigated the phenomena associated with the separation and purification of biodiesel produced from Ricinus communis oil seeds using experimental and theoretical approaches. The alkaline transesterification technique was used to produce the biodiesel from the Ricinus communis oil seeds which were later compared with standards based on EN and ASTM. Experimental investigation of the components in the mixture for separation and purification was conducted using the standard turbidimetric method for binodal solubility and tie-line compositions. The gas chromatographic technique was used to determine the composition of the homogeneous mixture. Novel components separation and purification of the Ricinus communis seed oil biodiesel was achieved using ternary diagrams highlighting the constituent components of the biodiesel at different temperatures for enhanced separation and purification. At the coexisting extract and raffinate phases, the orientation angle of the component compositions increases as the methanol concentration increases and temperature increases. The analysis of seed oil in terms of its physicochemical properties showed density, refractive index, acid value, and free fatty acid values of 905 kg/m³, 1.486, 0.79 mg KOH/g, and 0.390 mg KOH/g respectively. The fatty acid composition of the seed oil and biodiesel revealed that the major characteristics of the oil and biodiesel were defined by the presence of linoleic acid (C_18:2) and a ricinoleic acid hydroxyl group (C_18:1, OH) with compositions of approximately 30% and 20% respectively. Fourier Transform Infra-Red (FTIR) spectrometry analysis of the oil and biodiesel showed that the absorption spectrum in terms of the wave number (cm⁻¹) ranged from 1000 to 4000 cm⁻¹ with esters as the main functional group providing the main structural backbone. The presence of different fatty acids leads to lateral homogeneity of the biodiesel molecules which can serve to organize the molecules into discrete domains with different properties for enhanced separation and purification at the investigated temperatures. Optimal separation and purification were achieved at the different temperatures showing the castor oil biodiesel, glycerol, and methanol components system at the prevailing composition, time, and temperatures from the tie-lines and binodal solubility compositions. This approach provides a means for the design of a more efficient separation process for optimal biodiesel purification after production with knowledge of how the components are distributed in the ternary mixture after the transesterification reaction. This, leads to greater efficiency of the process, reducing material and operational costs and eliminating environmental issues linked with the biodiesel production process as the volume of wastewater generated would be hugely eradicated. The findings of this study will be useful in the setting up of a small-to-medium-size biodiesel production facility with improvement in the efficiency of product separation and purification.

This study aims to ascertain the possible health risks on humans to trace metals in Ossiomo River sediment via different exposure pathways. The pollution of river sediments by trace metals has raised countless concern for their potential biological noxiousness, environmental durability, and biological accumulation to humans along the food chain. Selected trace metals were analyzed based on required analytic approaches. Standard statistical tools were used to evaluate the records collected from the field. The outcomes from the field showed that the amount of the trace metals in the sediment were significantly higher in most samples and above set standard limits. The results of the hazard quotient (HQ) of the ingestion and dermal exposure were sourced from only Cd; 78.03, 6.93 and 7.47 for the ingestion pathway and 2840.20, 1445.46 and 1556.65 for the dermal pathway respectively. The hazard index (HI) obtained for Cd were ingestion (78.26, 6.96 and 7.49) and dermal (2841.87, 1446.31 and 1557.56) respectively. With more cumulative interactive effects in the children. The Cancer Risk gotten in this study was far greater in the children [Pb (0.644), Cr (3.35E+01) and Cd (4.76E+02)] than in the male [Pb (1.19E-01), Cr (6.20E+00) and Cd (8.82E+01)] and the female [Pb (0.128), Cr (6.67E+00) and Cd (9.50E+01)]. The TCR (Total Cancer Risk) values obtained were far beyond the set standards with Cd and Cr values of 659.09 and 46.32 respectively. We recommend further studies in this ecosystem in order to monitor the persistent anthropogenic impact and to anticipate any possible ecological risk that may propel human health risk impact.