Microplastic pollution in marine environment

Plastic is constructed from linking of hydrocarbon monomers and produced synthetic polymers. Plastic production reported is growing up steadily each year due to its demand based on Figure 2.1. Current production reported to be up to 348 million tonnes in 2017 (Plastic Europe, 2018)

Sorption of heavy metals onto polyethylene microbeads and its effect on seabass

Microbeads are one of the causes of microplastic pollution that is currently polluting ocean environment. It enters food chain via ingestion of marine vertebrates and invertebrates. This study aims to elucidate the interactions between polyethylene microbeads and heavy metals as well as to determine the possibility of polyethylene microbeads as heavy metal vectors for juvenile seabass. Two parts of experiments performed in this study, i.e. adsorption and ingestion. For the adsorption study, 10 g of virgin polyethylene microbeads (300 ^m) were submerged into 0.2, 0.4, 0.6, and 1.0 p,g/mL solutions of cadmium and chromium, and 0.4, 0.8, 1.2, 1.6, and 2.0 ^g/mL concentrations of lead in a batch of sorption experiments for 96 hours. In the ingestion experiment, seabass was exposed in control, single, co-exposure, and preloaded experiments. All exposure conditions were similar to the adsorption experiment with 10 g and 5 g of microbeads. Acid digestion and Atomic Absorption Spectroscopy were used to quantify the amount of heavy metal adsorbed on microbeads and accumulated in fish tissues. Maximum adsorption capacity of microbeads were 11 ^g/g for Cd, 1.7 ^g/g for Cr, and 9.0 ^g/g for Pb. The kinetic study concluded that the adsorption of polyethylene microbeads occurred at a pseudo-first-order reaction, which involves physical attraction. Adsorption isotherm fitted the Freundlich model signifying adsorption occurs rapidly and has the tendency to desorb due to weak binding. The rates of heavy metal adsorption onto microbeads were 11, 4.5, and 1.7 mL/g for Cd, Pb, and Cr, respectively, suggesting that Cd had a higher affinity towards microbeads polyethylene than Pb and Cr. In the ingestion study, most of the heavy metal were detected at the skin layer. Control experiment validated that, seabass uptake exposed microbeads via ingestion. The single experiment concluded that uptake of heavy metals in seabass tissues increased with concentration and time. The higher the amount of exposed microbeads, the higher the uptake of heavy metals in the gastrointestinal tract after 48 hours of co-exposure. This indicates that heavy metals were first adsorbed on the microbeads followed by their ingestion by the seabass. In the preloaded experiment, the concentration of heavy metal ions detected in the gastrointestinal tract was higher than the direct exposure in single and co-exposure. The uptake values in the preloaded experiment increased steadily with concentration, time, and quantity of microbeads. Preloaded exposure in this study verified that microbeads-loaded heavy metals were incidentally ingested by seabass during foraging. The incorporation of the three heavy metals in the ingestion study was performed using Minitab 16.0 multi analysis of variance (MANOVA). This study proved that polyethylene microbeads possess the potential to accumulate, transport, and transfer heavy metals from water to intestinal organ, thus increasing risk, threatening the marine food web, and possibly harming other consumers

Removal of nitrogen pollutant from domestic wastewater

Water as a medium for waste transport would be easily contaminated by human activities. Many methods have been proposed to treat contaminated water to protect human health and biodiversity (Z. Daud et al., 2017). Due to upgrade the existing wastewater treatment plant facilities, the typically advanced technologies have been proposed to remove many types of pollutant, effectively (Tchobanoglous, Burton, & Stensel, 2004). The development of wastewater treatment plant needs to be considered leading economic indicators to have low operational and maintenance costs (Lewandowski, 2015; Shammas, Wang, & Wu, 2009). Aerobic digestion (AD) has been known since 1950 as biological wastewater treatment process to treat wastewater by removing the pollutants for instance colloids, organic compounds and suspended solids to avoid the excessive pollutants released into the receiving water (Shammas and Wang, 2007)

Sorptive behaviour of chromium on polyethylene microbeads in artificial seawater

This study investigates the interactions between chromium (Cr) and microplastic under controlled laboratory conditions using low density polyethylene microbeads as plastic particles. Chromium was added to suspensions of in artificial seawater to investigate heavy metal adsorption on microbeads surface. Polyethylene microbeads proved to have affinity in providing surface area for chromium. It served as an effective sorption surface thus lowering amounts of chromium in seawater through adsorption process. The best percentage of heavy metals adsorbed to microbeads and adsorption capacity was 1.7 µg/g and 8.5 % at 1.0 µg/mL respectively. The maximum adsorption was monitored for 180 hours. Kinetic study was performed and fitted well in pseudo-first-order kinetic. In term of isotherm, dataset was in good agreement with both Langmuir and Freundlich with correlation at 0.977 and 0.9606 respectively. Adsorption of chromium to polyethylene microbeads had important implications for the potential role of microplastics, in this case microbeadschromium contaminated act as a quantified link in aquatic food webs

Sorptive behaviour of chromium on polyethylene microbeads in artificial seawater

This study investigates the interactions between chromium (Cr) and microplastic under controlled laboratory conditions using low density polyethylene microbeads as plastic particles. Chromium was added to suspensions of in artificial seawater to investigate heavy metal adsorption on microbeads surface. Polyethylene microbeads proved to have affinity in providing surface area for chromium. It served as an effective sorption surface thus lowering amounts of chromium in seawater through adsorption process. The best percentage of heavy metals adsorbed to microbeads and adsorption capacity was 1.7 µg/g and 8.5 % at 1.0 µg/mL respectively. The maximum adsorption was monitored for 180 hours. Kinetic study was performed and fitted well in pseudo-first-order kinetic. In term of isotherm, dataset was in good agreement with both Langmuir and Freundlich with correlation at 0.977 and 0.9606 respectively. Adsorption of chromium to polyethylene microbeads had important implications for the potential role of microplastics, in this case microbeadschromium contaminated act as a quantified link in aquatic food webs

Microplastics in sediment from Skudai and Tebrau river, Malaysia: a preliminary study

Plastic debris floating on surface water has now become an environmental issues concerning its abundance and fate. Generally, plastic debris that are fragmented into less than 5 mm in size is known as microplastics (MP). To date, discovery on the occurrence and impacts of MP in marine environments have been reported by many studies. However, less investigation has been carried out in freshwater environments. The occurrence of MP in Malaysia is also unknown. Thus, the present study has characterised the abundance of MP between Skudai and Tebrau River. The quantification of MP levels in these channels are pertinent since both rivers are listed among polluted rivers in Malaysia with high amount of rubbish. Surface sediments were collected with a box corer and MP were extracted via density separation. The inspection of particles was carried out under microscope and were categorized based on shape, colour, and size. Preliminary results showed that the concentration of MP was much higher in Tebrau than of Skudai River. The study demonstrates that the abundance of MPs in both urban rivers may possibly be affected by weathering breakdown of large plastic materials since these locations are well-known for fishing and industrial areas

Microplastics in sediment from Skudai and Tebrau river, Malaysia: a preliminary study

Plastic debris floating on surface water has now become an environmental issues concerning its abundance and fate. Generally, plastic debris that are fragmented into less than 5 mm in size is known as microplastics (MP). To date, discovery on the occurrence and impacts of MP in marine environments have been reported by many studies. However, less investigation has been carried out in freshwater environments. The occurrence of MP in Malaysia is also unknown. Thus, the present study has characterised the abundance of MP between Skudai and Tebrau River. The quantification of MP levels in these channels are pertinent since both rivers are listed among polluted rivers in Malaysia with high amount of rubbish. Surface sediments were collected with a box corer and MP were extracted via density separation. The inspection of particles was carried out under microscope and were categorized based on shape, colour, and size. Preliminary results showed that the concentration of MP was much higher in Tebrau than of Skudai River. The study demonstrates that the abundance of MPs in both urban rivers may possibly be affected by weathering breakdown of large plastic materials since these locations are well-known for fishing and industrial areas

Kinetic and equilibrium studies for dye adsorption onto sugarcane Bagasse and rice husks

The textile industry discharges large quantities of highly colored wastewater from industrial processes using chemical components. Many dyes are designed to be chemically stable so that they are difficult to decolorize due to their complex structure and synthetic origin. The dye waste is subsequently released directly to water bodies during the textile finishing process. This improper released has adverse effects on the environment and may reduce photosynthesis in aquatic plants. Even though adsorption techniques have been widely used to remove textile dye from waters, the kinetic models used to describe the adsorption of textile dye onto a porous material is still not yet fully understood. This study investigated different applications of absorbent from sugarcane bagasse (SB) and rice husks (RH) in removing color from aqueous solution and the application of kinetic model for adsorption of color from aqueous solutions onto SB and RH. A batch study was carried out under various mass of adsorptions and contact time with constant with the initial concentration of aqueous solution was 400ADMI. The data obtained from batch experiments showed that the removal of RH (93%) was more efficient than SB (49%). This study also advanced the understanding on the kinetic adsorption study of RH and SB to prove that the adsorbents have potential to reduce dye from synthetic solution. The contribution of this study in the removal of significant dye pollutants from industrial wastewater will require future assessment in a prospective wastewater treatment facility setting