Occurrence and level of emerging organic contaminant in fish and mollusk from Klang River estuary, Malaysia and assessment on human health risk

The occurrence, level, and distribution of multiclass emerging organic contaminants (EOCs) in fish and mollusks from the Klang River estuary were examined. The targeted EOCs for this assessment were phenolic endocrine disrupting compounds (bisphenol A, 4-OP, and 4-NP), organophosphorous pesticides (quinalphos, chlorpyrifos, and diazinon), estrogenic hormones (E2, E1, and EE2), and pharmaceutically active chemicals (primidone, sulfamethoxazole, dexamethasone, diclofenac, amoxicillin, progesterone, and testosterone). Results from this study showed that the prevalent contamination of the Klang River estuary by EOCs with diclofenac, bisphenol A, progesterone, and amoxicillin were predominantly detected in fish and mollusks. Among the EOCs, diclofenac and progesterone had the highest concentrations in fish and mollusk samples, respectively. The concentrations of diclofenac and progesterone in fish and mollusk samples range from 1.42 ng/g to 10.76 ng/g and from 0.73 ng/g to 9.57 ng/g, respectively. Bisphenol A should also be highlighted because of its significant presence in both fish and mollusks. The concentration of bisphenol A in both matrices range from 0.92 ng/g to 5.79 ng/g. The calculated hazard quotient (HQ) for diclofenac, bisphenol A, and progesterone without consideration to their degradation byproduct were less than one, thus suggesting that the consumption of fish and mollusks from the Klang River estuary will unlikely pose any health risk to consumers on the basis of the current assessment. Nonetheless, this preliminary result is an important finding for pollution studies in Malaysian tropical coastal ecosystems, particularly for organic micropollutant EOCs, and can serve as a baseline database for future reference

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

Multiclass emerging organic pollution and associated risks in the Klang River estuary in Malaysia

The occurrence, distribution and sources of multiclass emerging organic contaminants (EOCs) in the environmental matrices (estuarine water, sediment and biota) from Klang River estuary were examined. The targeted EOCs for this assessment were endocrine disrupting compounds (bisphenol A, 4-0P, 4-NP, E2, El and EE2), organo phosphorous pesticides (quinalphos, chlorpyrifos, diazinon) and pharmaceutically active compounds (primidone, su1famethoxazo1e, dexamethasone, diclofenac, amoxicillin, progesterone, testosterone). Analytical methods of quantification for determination of multi class EOCs were developed for three components of environmental matrices, namely estuarine water, sediment and biota matrices. The developed analytical methods were validated for linearity, extraction efficiency (% recovery), precision, method detection limit as well as matrix effects. Satisfactory optimization were achieved for the developed analytical methods with extraction efficiency between 51 to 126%, as well as excellent linearity (r > 0.991) and precision (%CV < 20). Results from this field study showed that prevalent contamination of Klang River estuary by EOCs with several compounds such as diclofenac, bisphenol A, progesterone, estrone and amoxicillin were predominantly detected in the three environmental matrices. For estuarine water samples, bisphenol A was the compound mostly detected, contributed about 54.77% of total concentration followed by amoxicillin (39.17%), estrone (2.16%) and diclofenac (1.67%). The highest concentration ofEOCs in surface water samples was found in BPA at 597.30 ng/L, followed by amoxicillin at 102.31 ng/L. While for sediment samples, bisphenol A was the highest concentration detected at 16.84 ng/g followed by diclofenac (13.88 ng/g) and estrone (12.47 ng/g). The percentage of contribution (% of total concentration) is in order of bisphenol A (49.68%), diclofenac (16.19%), progesterone (10.37%) and El (9.25%). As for biota matrices, diclofenac (10.76 ng/g) was detected at the highest concentration in fish samples, while progesterone (9.57 ng/g) was the highest concentration found in the molluscs. Principal component analysis (PCA) has successfully extracted four principle components, revealing that the sources ofEOCs in the estuary originated from water/waste treatment plants, medical waste discharges, industrial pollution and aquaculture/livestock activities. Estimation of human health risk assessment, calculated as hazard quotient (HQ) were less than 1, suggesting the consumption of fish and mollusc from Klang River estuary will not pose any health 'risk to the consumers. Meanwhile, environmental risk assessment, expressed as risk quotients (RQs) for all targeted compounds were also less than 1 for the three test species (phytoplankton, zooplankton and fish) evaluated. Hence, the targeted EOCs have not indicated significant risks to the ecosystem during the current assessment. Nonetheless, result from this field assessment is an important finding for pollution studies in Malaysian tropical coastal ecosystems particularly for organic micro-pollutant EOCs and can also serve as a baseline database for future reference