Chuck Chuan Ng

Molluscs, being highly susceptible to potentially toxic elements (PTEs) and easily accessible for human consumption, play a critical role in research on PTE pollution. This study focuses on Kukup Fishing Village in Johor, Malaysia, to investigate the levels of Cd, Cu, and Pb in seawater, sediment, and the soft tissues and shells of the gastropods Nerita articulata (lined nerite snail) and Cerithidea obtusa (obtuse horn shell). All collected samples were chemically digested before being analysed using the flame atomic absorption spectrometer (F-AAS). It is found that the PTEs are mostly accumulated in soft tissues and shells, followed by sediments and seawater, respectively. Besides, the results revealed that all study locations exhibited moderate to severe pollution, and the PTE concentrations in sea snails exceeded the thresholds set by the Malaysian Food Regulations (1985). The mean concentrations of the studied elements in the seawater, soft tissues, and shells of two studied species were found to be in the order of Pb > Cu > Cd. Additionally, Pb was heavily accumulated in the soft tissues of both species: N. articulata (712.587–723.242 ppm) and C. obtusa (705.935–708.626 ppm). Compared to N. articulata, C. obtusa showed a higher capacity to accumulate Cd (3.702–4.350 ppm) and Cu (92.687–157.445 ppm), particularly in the soft tissues. The shell of N. articulata and the soft tissue of C. obtusa were identified as potential biomonitoring indicators for Cd and Cu, respectively. It is recommended that the local Malaysian authorities could strengthen environmental management, implement regular monitoring, and raise public awareness to minimise seafood consumption from polluted areas as these measures could aid to reduce pollution, protect marine ecosystems, and safeguard public health. Graphical Abstract

The accumulation of potentially toxic elements (PTEs) has raised public awareness due to harmful contamination to both human and marine creatures. This study was designed to determine the concentration of copper (Cu), zinc (Zn), cadmium (Cd), and nickel (Ni) in the intestine, kidney, muscle, gill, and liver tissues of local commercial edible fish, fourfinger threadfin (Eleutheronema tetradactylum), and black pomfret (Parastromateus niger) collected from Morib (M) and Kuala Selangor (KS). Among the studied PTEs, Cu and Zn were essential elements to regulate body metabolism with certain dosages required while Cd and Ni were considered as non-essential elements that posed chronic and carcinogenic risk. The concentration of PTEs in fish tissue samples was analyzed using flame atomic absorption spectrometry (F-AAS). By comparing the concentration of PTEs in fish tissues as a bioindicator, the environmental risk of Morib was more serious than Kuala Selangor because both fish species collected from Morib resulted in a higher PTEs concentration. For an average 62 kg adult with a fish ingestion rate (FIR) of 0.16 kg/person/day in Malaysia, the estimated weekly intake (EWI) of Cd from the consumption of E. tetradactylum (M: 0.0135 mg/kg; KS: 0.0134 mg/kg) and P. niger (M: 0.0140 mg/kg; KS: 0.0132 mg/kg) had exceeded the provisional tolerable weekly intake (Cd: 0.007 mg/kg) established by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) and oral reference dose (ORD) values of Cd (0.001 mg/kg/day) as provided by the United States Environmental Protection Agency (USEPA) regional screening level, thus it posed chronic risks for daily basis consumption. Besides, the value of the carcinogenic risk of Cd (0.7⁻³ to 0.8⁻³) and Ni (0.5⁻³ to 0.6⁻³) were in between the acceptable range (10⁻⁶ to 10⁻⁴) of the health index that indicates a relatively low possibility cancer occurrence to the consumers in both Morib and Kuala Selangor. This study recommended FIR to be 0.80 kg/person/day to reduce the possibility of posing chronic and carcinogenic risks while at the same time obtaining the essential nutrients from the fish. Graphical Abstract

The environmental concern of plastic waste (PW) generation has escalated to an alarming level due to the versatility and high demand in various applications. In order to search for an effective way to utilise PW, reusing them for the production of construction material appears as an environmentally-friendly approach. This is also because conventional construction materials often consume high energy during production has caused many environmental impacts. This review paper summarises the previous studies on reusing various PW as raw material and aggregate for construction and its properties with special attention to bricks and paving blocks. This paper begins by illustrating on the properties of plastics and the impacts of PW to the environment. Followed by discussion on reusing PW and its impacts on the overall properties of construction material. This review found that limited studies had been conducted on the usage of PW in the production of the paving block. Besides, most of the studies focused predominantly on compressive strength and water absorption as the main parameters to evaluate the characteristics of bricks and paving blocks. It is concluded that the use of PW in construction material could possibly serve as a sustainable source for construction material in the future.