Nanomaterials, classified as emerging pollutants that are toxic to the environment, are known to bioaccumulate across different trophic levels in the aquatic ecosystem. This study therefore investigates the distribution of silver and silver nanoparticles (AgNPs) in the aquatic environment of Skudai River, Johor, Malaysia. Water, sediment, plant, and fish samples were collected seasonally along four sites along Skudai River between May 2018 and April 2019. All samples were subjected to Ag analysis using an inductively coupled plasma mass spectrometer (ICP-MS). The analysis demonstrated that the concentration of Ag detected in water samples ranging from 0.001 to 0.505 mg/L was the lowest, whereas in the plants, 0.235 to 4.713 mg/kg of Ag was quantified. The upper sediments contained 0.036 to 28.115 mg/kg of Ag, whilst fish samples presented the highest accumulation of Ag, averaging between 9.144 and 53.784 mg/kg of Ag. Subsequently, the formation of silver nanoparticles was further proven by TEM-EDX analysis, where the detected size of AgNPs ranged from 20 nm to 35 nm. The overriding conclusion implied by bioaccumulation factor (BAF) and biota–sediment accumulation factor (BSAF) calculations suggested that Skudai River was indeed polluted by Ag and AgNPs. The values obtained stipulated that silver accumulation is occurring at an alarming rate and could therefore endanger fish consumers.

PREPARATION AND CHARACTERIZATION OF ACTIVATED CARBON FROM OIL PALM EMPTY FRUIT BUNCH WASTES USING ZINC CHLORIDE

This study aimed to investigate the impact of nonionic surfactants on the efficacy of fluorine degradation by Polyporus sp. S133 in a liquid culture. Fluorene was observed to be degraded in its entirety by Polyporus sp. S133 subsequent to a 23-day incubation period. The fastest cell growth rate was observed in the initial 7 days in the culture that was supplemented with Tween 80. The degradation process was primarily modulated by the activity of two ligninolytic enzymes, laccase and MnP. The highest laccase activity was stimulated by the addition of Tween 80 (2443U/L) followed by mixed surfactant (1766U/L) and Brij 35 (1655U/L). UV-vis spectroscopy, TLC analysis and mass spectrum analysis of samples subsequent to the degradation process in the culture medium confirmed the biotransformation of fluorene. Two metabolites, 9-fluorenol (λmax 270, tR 8.0min and m/z 254) and protocatechuic acid (λmax 260, tR 11.3min and m/z 370), were identified in the treated medium.

This study explored the low-cost adsorbent of orange peel and spent tea leave for Methylene Blue (MB) and Remazol Brilliant Blue R (RBBR) dyes removal from aqueous solutions. The removal rate and adsorption capacity on the adsorption of dyes were investigated using the batch adsorption study. The present study indicates that the MB was easier to remove by both orange peel and spent tea leave compared to RBBR with percentage removal of 95.72 % and 99.02 % respectively. The effects of morphology, functional groups, and surface area of adsorbents were investigated by using FESEM, FTIR, and BET. The result proved that orange peel and spent tea leave were promising material as an alternative adsorbent for the removal of MB from aqueous solution.