Identification of Micro-plastics (MPs) in Conventional Tap Water Sourced from Thailand

In a period when MP contamination of drinking water is a great concern, this study focused on the size- and morphology-based count, and polymeric identification of plastic particles in tap water sourced from Thailand. A total of 45 human consumable samples (each 1 L) were collected at Thammasat University. The average MP counts sorted by Nile Red tagging were 56.0±14.0 p/L (6.5-53 µm) and 21.0±7.0 p/L (53-300 µm), while those found by optical microscopic observations were 13.0±5.0 p/L (300-500 µm) and 6.0±3.0 p/L (≥ 500 µm). A significantly high MP amount was observed in the 6.5-53 µm fraction. Fibers dominated in all samples, accounting for 58% of the particle count. Most ≥ 300 µm particles tested by ATR-FT-IR spectroscopy were confirmed to be polymeric, identified as PE, PVC, PET, PA, PTFE, PP, and PAM. These particles may have escaped from the treatment plant or were added along the water distribution network. Since MPs in drinking water constitute a potential health risk by exposing humans to direct plastics intake, MP contamination in water supply systems should be controlled

Identification of Micro-plastic Contamination in Drinking Water Treatment Plants in Phnom Penh, Cambodia

Micro-plastics (MP) contamination in drinking water has become a global concern. Its negative impacts on human health have been reported. This study identified the presence of MP in two different drinking water treatment plants (WTP) in Phnom Penh, Cambodia, and investigated their removal efficiency. Samples were collected from the inlet, sedimentation, sand filtration, and distribution tank to quantify the removal by each unit. An optical microscope and a fluorescence microscope were used to detect the MP in four size fractions: 6.5-20, 20-53, 53-500, and >500 µm. Fourier transform infrared spectroscopy (FT-IR) was used to identify the polymer type for particles with size fractions of 53-500 and >500 µm. The results showed that the MP counted in WTP1 were 1180.5 ± 158 p/L in the inlet and 521 ± 61 p/L in the distribution tank. In WTP2, the MP counted were 1463 ± 126 p/L in the inlet and 617 ± 147 p/L in the distribution tank. The smaller size fraction of 6.5-20 µm predominated at each sampling location. Fragments were the most abundant morphology compared to fibers in all sampling points of both plants. PET predominated and the overall percentages for the inlet tank were 28.8% and 26%, followed by PE with 27.1% and 20.8% in WTP1 and WTP2, respectively. Other common polymer types were PP, PA, PES, and cellophane, while all others accounted for less than 5%. The results of the study showed that a significant number of MP remained in the water distribution system

Microplastics Contamination in a High Population Density Area of the Chao Phraya River, Bangkok

Microplastics (MPs) are distributed globally, including in aquatic environments. While a large number of studies on MPs in marine environments have been performed, few studies are available in freshwater environments. Therefore, the distribution of MPs in surface water and sediment from the Chao Phraya River at Tha Prachan, a high population density area of Bangkok, was investigated. Water samples were collected by a manta trawl with a net mesh size of 300 mm. Sediment samples were collected by a Van Veen grab sampler. The total number and concentration of MPs in the water samples were found to be 104 particles/m3 and 805.20 mg/m3, respectively. The dominant MPs were fragments, 0.5 to 1.0 mm in size, for the water samples. In the sediment, MPs were detected only in a size range of 0.053 to 0.5 mm with a total number and concentration of 2,290 particles/kg and 650 mg/kg, respectively. The presence of different types of MPs was confirmed by Fourier-transform infrared spectroscopy with a dominant abundance of polypropylene, polyethylene, and polystyrene. In brief, this study suggests that high levels of MPs occur not only in the water but also in the sediment of the Chao Phraya River at Tha Prachan area

Activity of Carbon-Based Solid Acid Catalyst Derived from Palm Empty Fruit Bunch for Esterification of Palmitic Acid

The activity of a heterogeneous solid acid catalyst derived from palm empty fruit bunch, synthesized through the direct in-situ H2SO4 impregnation was investigated for the esterification of palmitic acid. The prepared catalyst was characterized by scanning electron microscopy (SEM), Nitrogen adsorption and desorption isotherm, Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis (TGA). It was also analyzed for acid density and elemental composition. The results revealed that the esterification efficiency increases with increasing reaction time, temperature, and methanol loading up to an optimum value. The catalyst showed an excellent activity resulting in >98% esterification efficiency using 5 wt% catalyst, a 6:1 methanol to palmitic acid molar ratio, at 80°C for 5 h in an open reflux reactor, for the reaction conditions. The catalyst was employed in three consecutive runs without considerable loss of the activity. The obtained high catalytic activity is attributed to the high acid density due to the presence of strong (SO3H) and weak (COOH, OH) acid sites in the hydrophobic carbon structure