FRACTIONATION OF As, Co, Cu AND Zn BY SEQUENTIAL EXTRACTION IN SURFACE SEDIMENT OF KUALA TERENGGANU RIVER ESTUARY

Development and urbanization processes around Terengganu River estuary are expected to release a significant amount of heavy metals into the existing bottom sediment. However, information on how and why these metals are attached into specific fraction of sediments is still lacking. Therefore, this study aimed to explain the heavy metal concentration distribution in each available fraction at Terengganu River estuary. In this study, nine surface sediments originated from various human activities area in Terengganu River estuary were collected during four different sampling sessions in 2017. Heavy metal content from the collected sediments were extracted using 3-steps BCR sequential extraction method followed by detection using Inductively Coupled Plasma Mass-Spectrometer (ICP-MS) and we discovered that the total concentration of Arsenic (As), Cobalt (Co), Copper (Cu), and Zinc (Zn) ranged from 2.18 to 17.48 mg/kg dry wt., 2.53 to 20.53 mg/kg dry wt., 1.01 to 13.13 mg/kg dry wt., and 6.10 to 65.71 mg/kg dry wt., respectively. Dominance of metals in each fraction can be arranged as follows: As: residual > reducible > exchangeable > oxidizable; Co: residual > exchangeable > reducible > oxidizable; Cu: residual > oxidizable > reducible > exchangeable; Zn: residual > exchangeable > reducible > oxidizable. Availability of metals in sediment at Terengganu River estuary is limited since that majority of metals resides in non-mobilisable fraction of the sediment. In essence, sequential extraction provides information regarding the metals’ fractionation, availability and mobility, which could be used in assessing the environmental contamination in the area

Effects of temperature and metals (zinc and cadmium) in embryonic stage of Anabas testudineus : an alternative freshwater fish embryo test in the Southeast Asia Region

The fish embryo acute toxicity test (FET) was proposed as a promising alternative to the general practice of fish acute toxicity test (FAT). To date, the available information on freshwater fish embryos in Southeast Asia is limited. Hence, this study aims to present preliminary data on single and combined exposure effects of temperature and metals (zinc and cadmium) on the embryonic development of Anabas testudineus. Over 80% of the embryos died after 10 h post-fertilization (hpf) in 1.59, 7.02, and 13.0 mg/L cadmium treatments, whereas the same effect was only observed in 49.6 and 146 mg/L of zinc treatments as early as 8 hpf. The optimum temperature for embryos ranged from 27 to 34 °C, with a survival rate greater than 90% was recorded. The combined test of zinc + cadmium showed the additive effect with approximately 80% mortality at 12 hpf, while the combination of temperature + cadmium had increased the mortality rate up to 100% at 16 hpf. The constant temperature even at optimum rearing value was found to increase cadmium uptake in the embryos and magnified the concentration higher than in water. Therefore, this study suggests climbing perch (Anabas testudineus) could be an alternative FET test model in this region

Accumulation of heavy metals in farmed lates calcarifer of a tropical coastal lagoon

Heavy metals content in seafood, especially fish species has been of increasing concern to the human health. Nowadays, with increasing dependency towards farmed fish for sources of dietary protein and essential minerals, this heavy metals contamination in fishes are still questionable. This study aimed to investigate the accumulation of heavy metals in farmed fish, Lates calcarifer different organs from Setiu tropical coastal lagoon, Terengganu, Malaysia throughout its out-growing phase in the farm from the fingerling release up to their marketable size. Selected heavy metals namely Cu (Max:291.5±99.31), Zn (Max: 84.89±12.76), As (Max: 26.01±5.170), Cd (Max: 1.634±0.014), Hg (Max: 0.165±0.029) and Pb (Max: 0.634±0.550) in the fish was analyzed using ICP-MS after Teflon bomb closed digestion. The metal accumulation in each organ were generally found in the order of liver > gill > muscle. The concentrations of Cd and Zn in the liver were found to increase with fish size in each organ based on the association found in the principal component analysis (PCA). Meanwhile the overall findings observed negative correlation with L. calcarifer growth in fish size for all other heavy metals and organs. The amount of As in the fish muscle throughout its growth can be potentially harmful to humans with the highest averaged concentration at 3.29±0.65 mg/kg dw above the standard set by the Malaysian Food Regulation (1985) of more than 1 mg/kg. Meanwhile, all the other heavy metals were relatively safe and the concentrations well below the standard set by both national and international guidelines

Positive and negative effects of COVID-19 pandemic on aquatic environment: a review

In December 2019, a novel coronavirus called severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) outbreak was reported for the first time in Wuhan, Hubei province, China. This coronavirus has been referred as Coronavirus Disease 2019 or COVID-19 by World Health Organization (WHO). The spread of COVID-19 has become unstoppable, infecting around 93.5 million people worldwide, with the infections and deaths still increasing. Today, the entire planet has changed due to the greatest threat on the planet since the introduction of this lethal disease. This pandemic has left the world in turmoil and various measures have been taken by many countries including movement control order or lockdown, to slow down or mitigate the infection. Since the lockdown has been implemented almost in all affected countries, there has been a significant reduction in anthropogenic activity, including a reduction in industrial operations, vehicle numbers, and marine-related activities. All of these changes have also led to some unexpected environmental consequences. As a result of this lockdown, it had a positive and negative impact on the environment including the aquatic environment. Hence this review will therefore focus on the good and bad perspectives of the lockdown toward the aquatic environment