Characterization of microplastics in the water and sediment of Baram River estuary, Borneo Island.

The Baram River is one of the largest rivers in Sarawak, where many large industries, such as plywood, sawmills, shipyards, interisland ports, and other wood-based industries are located along the river. Microplastic contamination has become a widespread and growing concern worldwide because of the small sizes of microplastics and their presence in seafood such as fish, squid, scallop, crabs, shrimp, and mussels. In this study, microplastics were found in all sampling stations. Out of the 4017 microplastics found in the water and sediment, microplastics fragment accounted for 67.8% of total microplastics, followed by fiber, film, pellet, and foam. Five microplastic polymer types were detected by ATR-FTIR, including polyethylene (PE), polyester (PET) fibers, silicon polymer, nitrile, and polystyrene (PS). The most common microplastics size range in Baram River was 0.3-1 mm, with blue as the highly abundant color.

Pesticides in Drinking Water-A Review.

The ubiquitous problem of pesticide in aquatic environment are receiving worldwide concern as pesticide tends to accumulate in the body of the aquatic organism and sediment soil, posing health risks to the human. Many pesticide formulations had introduced due to the rapid growth in the global pesticide market result from the wide use of pesticides in agricultural and non-agricultural sectors. The occurrence of pesticides in the water body is derived by the runoff from the agricultural field and industrial wastewater. Soluble pesticides were carried away by water molecules especially during the precipitation event by percolating downward into the soil layers and eventually reach surface waters and groundwater. Consequently, it degrades water quality and reduces the supply of clean water for potable water. Long-time exposure to the low concentration of pesticides had resulted in non-carcinogenic health risks. The conventional method of pesticide treatment processes encompasses coagulation-flocculation, adsorption, filtration and sedimentation, which rely on the phase transfer of pollutants. Those methods are often incurred with a relatively high operational cost and may cause secondary pollution such as sludge formation. Advanced oxidation processes (AOPs) are recognized as clean technologies for the treatment of water containing recalcitrant and bio-refractory pollutants such as pesticides. It has been adopted as recent water purification technology because of the thermodynamic viability and broad spectrum of applicability. This work provides a comprehensive review for occurrence of pesticide in the drinking water and its possible treatment.

Role of nanocatalyst in the treatment of organochlorine compounds - A review.

Since a few centuries ago, organochlorine compounds (OCs) become one of the threatened contaminants in the world. Due to the lipophilic and hydrophobic properties, OCs always discover in fat or lipid layers through bioaccumulation and biomagnification. The OCs are able to retain in soil, sediment and water for long time as it is volatile, OCs will evaporate from soil and condense in water easily and frequently, which pollute the shelter of aquatic life and it affects the function of organs and damage system in human body. Photocatalysis that employs the usage of semiconductor nanophotocatalyst and solar energy can be the possible alternative for current conventional water remediation technologies. With the benefits of utilizing renewable energy, no production of harmful by-products and easy operation, degradation of organic pollutants in rural water bodies can be established. Besides, nanophotocatalyst that is synthesized with nanotechnology outnumbered conventional catalyst with larger surface area to volume ratio, thus higher photocatalytic activity is observed. In contrast, disadvantages particularly no residual effect in water distribution network, requirement of post-treatment and easily affected by various factors accompanied with photocatalysis method cannot be ignored. These various factors constrained the photocatalytic efficiency via nanocatalysts which causes the full capacity of solar photocatalysis has yet to be put into practice. Therefore, further modifications and research are still required in nanophotocatalysts' synthesis to overcome limitations such as large band gaps and photodecontamination.

Exploring the potential of halotolerant bacteria for biodegradation of polycyclic aromatic hydrocarbon.

The present study aimed to determine the degradation and transformation of three-ring PAHs phenanthrene and anthracene by Cryptococcus sp. MR22 and Halomonas sp. BR04 under halophilic conditions. The growth progress of Cryptococcus sp. MR22 and Halomonas sp. BR04 on anthracene and phenanthrene was monitored by colony-forming unit (CFU) technique. The growth of the bacteria was maintained at a maximum concentration of 200 mg/L of all tested hydrocarbon, indicating that Cryptococcus sp. MR22 and Halomonas sp. BR04 significantly perform in the removal of the PAH-contaminated medium at low concentrations. The fit model to represent the biodegradation kinetics of both PAHs was first-order rate equation The extract prepared from cells supplemented with three different substrates exhibited some enzymes such as hydroxylase, dioxygenase, laccase and peroxidase. The results suggest that both strains had an impressive ability in the degradation of aromatic and aliphatic hydrocarbon but also could tolerate in the extreme salinity condition.

An empirical study of construction and demolition waste generation and implication of recycling.

Associated with the continuing increase of construction activities such as infrastructure projects, commercial buildings and housing programs, Bangladesh has been experiencing a rapid increase of construction and demolition (C&D) waste. Till now, the generation rate of C&D waste has not been well understood or not explicitly documented in Bangladesh. This study aims to provide an approach to estimate C&D waste generation using waste generation rates (WGR) through regression analysis. Furthermore, analyses the economic benefit of recycling C&D waste. The results revealed that WGR 63.74 kg/m2 and 1615 kg/m2 for construction and demolition activities respectively. Approximately, in financial year (FY) 2016, 1.28 million tons (0.149 construction and 1.139 demolition) waste were generated in Dhaka city, of which the three largest proportions were concrete (60%), brick/block (21%) and mortar (9%). After collection they were dumped in either landfills or unauthorized places. Therefore, it can be summarized as: waste is a resource in wrong place. The results of this study indicate that rapid urbanization of Dhaka city would likely experience the peak in the generation of C&D waste. This paper thus designates that C&D waste recycling is an entrepreneurial activity worth venturing into and an opportunity for extracting economic and environmental benefits from waste. The research findings also show that recycling of concrete and brick waste can add economic value of around 44.96 million USD. In addition, recycling of C&D waste leads to important reductions in CO2 emissions, energy use, natural resources and illegal landfills. Therefore, the findings of WGR and economic values provide valuable quantitative information for the future C&D waste management exercises of various stakeholders such as government, industry and academy.

Decolorization and biotransformation pathway of textile dye by Cylindrocephalum aurelium.

Due to environmental concern, the research to date has tended to focus on how textile dye removal can be carried out in a greener manner. Therefore, this study aims to evaluate the decolorization and biotransformation pathway of Mordant Orange-1 (MO-1) by Cylindrocephalum aurelium RY06 (C. aurelium RY06). Decolorization study was conducted in a batch experiment including the investigation of the effects of physio-chemical parameters. Enzymatic activity of C. aurelium RY06 during the decolorization was also investigated. Moreover, transformation and biodegradation of MO-1 by C. aurelium RY06 were observed using the gas chromatography-mass spectrometry. Manganese peroxidase, lignin peroxidase, laccase, 1,2-dioxygenase, and 2,3-dioxygenase enzymes were detected during the decolorization. In general, the present work concluded that the MO-1 was successfully degraded by C. aurelium RY06 and transformed to be maleic acid and to be isophtalic acid.

Characterization of pyrene and chrysene degradation by halophilic Hortaea sp. B15.

Polycyclic aromatics hydrocarbons (PAHs) are ubiquitous and toxic pollutants that are dangerous to humans and living organism in aquatic environment. Normally, PAHs has lower molecular weight such as phenanthrene and naphthalene that are easy and efficient to degrade, but high-molecular-weight PAHs such as chrysene and pyrene are difficult to be biodegraded by common microorganism. This study investigated the isolation and characterization of a potential halophilic bacterium capable of utilizing two high-molecular-weight PAHs. At the end of the experiment (25-30 days of incubation), bacterial counts have reached a maximum level (over 40 × 1016 CFU/mL). The highest biodegradation rate of 77% of chrysene in 20 days and 92% of pyrene in 25 days was obtained at pH 7, temperature 25 °C, agitation of 150 rpm and Tween 80 surfactant showing to be the most impressive parameters for HMWPAHs biodegradation in this research. The metabolism of initial compounds revealed that Hortaea sp. B15 utilized pyrene to form phthalic acid while chrysene was metabolized to form 1-hydroxy-2-naphthoic acid. The result showed that Hortaea sp. B15 can be promoted for the study of in situ biodegradation of high molecular weight PAH.