Microplastic (MP) particles are considered noxious pollutants due to their presence in aquatic habitats at almost every level of the food chain. Thus, the entry of MP particles into marine waterbodies has triggered a common research interest. Until recently, the toxicity of polystyrene towards aquatic creatures in comparison to other polymers has not been widely investigated. This article provides an extensive overview of the occurrence of microplastic particles, the route of polystyrene (PS) in the aquatic ecosystem, the PS properties characterization, and its noxious effects on the aquatic biota, particularly fishes and microalgae. Alarming high levels of polystyrene were found in urban, coastal, and rural surface waters and sediments. The fast-screening technique began with a stereoscope to determine the polystyrene particles’ shape, size, and color on the organism. SEM and complemented by micro FTIR or Raman spectroscopy were used to evaluate MP’s polymer structures. The findings present evidence suggesting that polystyrene buildup in fish can have long-term and unknown consequences. Meanwhile, the presence of polystyrene on microalgae causes a decrease in chlorophyll concentration and photosynthetic activity, which may disrupt photosynthesis by interfering with the electron characters and leading to the production of reactive oxygen species (ROS).

This paper reports on the potential use of geopolymer in the drilling process, with respect to tool wear and surface roughness. The objectives of this research are to analyze the tool life of three different economy-grade drill bit uncoated; high-speed steel (HSS), HSS coated with TiN (HSS-TiN), and HSS-cobalt (HSS-Co) in the drilling of geopolymer and to investigate the effect of spindle speed towards the tool life and surface roughness. It was found that, based on the range of parameters set in this experiment, the spindle speed is directly proportional to the tool wear and inversely proportional to surface roughness. It was also observed that HSS-Co produced the lowest value of surface roughness compared to HSS-TiN and uncoated HSS and therefore is the most favorable tool to be used for drilling the material. For HSS, HSS coated with TiN, and HSS-Co, only the drilling with the spindle speed of 100 rpm was able to drill 15 holes without surpassing the maximum tool wear of 0.10 mm. HSS-Co exhibits the greatest tool life by showing the lowest value of flank wear and produce a better surface finish to the sample by a low value of surface roughness value (Ra). This finding explains that geopolymer is possible to be drilled, and therefore, ranges of cutting tools and parameters suggested can be a guideline for researchers and manufacturers to drill geopolymer for further applications.