Pollutants, Volume 1, Issue 2 (June 2021) – 3 articles

Microplastics are discharged into the environment through human activities and are persistent in the environment. With the prevalent use of plastic-based personal protective equipment in the prevention of the spread of the COVID-19 virus, the concentration of microplastics in the environment is envisaged to increase. Potential ecological and health risks emanate from their potential to adsorb and transport toxic chemicals, and ease of absorption into the cells of living organisms and interfering with physiological processes. This review (1) discusses sources and pathways through which microplastics enter the environment, (2) evaluates the fate and behavior of microplastics, (3) discusses microplastics in African aquatic systems, and (4) identifies research gaps and recommends remediation strategies. Importantly, while there is significant microplastics pollution in the aquatic environment, pollution in terrestrial systems are not widely studied. Besides, there is a dearth of information on microplastics in African aquatic systems. The paper recommends that the governments and non-governmental organizations should fund research to address knowledge gaps, which include: (1) the environmental fate of microplastics, (2) conducting toxicological studies under environmentally relevant conditions, (3) investigating toxicity mechanisms to biota, and developing mitigation measures to safeguard human health, and (4) investigating pollutants transported by microplastics. Moreover, regulatory measures, along with the circular economy strategies, may help reduce microplastic pollution. Full article

Globally, the frequency of fishkill episodes is increasing, owing to natural and human-induced modification of aquatic ecosystems. A massive fishkill took place on 22 October 2017 along an approximately 1.5 km stretch of the Jhelum River in Srinagar City, India. Thousands of fish died during this specific event, not lasting more than three hours, creating chaos and panic among the local population and government circles. In this context, affected fish were assessed for three morphological parameters, which include skin color, eye appearance, and skin texture. To back our findings, three critical water-quality parameters, including pH, water temperature, and dissolved oxygen essential for the survival of fishes were assessed in the affected river stretch. This study assumes importance given that water-quality observation stations for monitoring the health of the Jhelum River are lacking in the highly urbanized Srinagar City. The morphological examination of fish samples revealed discoloration, bulging eyes, and rough skin texture, indicating chemical contamination of waters in the affected river stretch. The water quality analysis revealed neutral pH (7.2), normal temperature (15.6 °C), and mildly depleted dissolved oxygen (6 mg L⁻¹) levels. While the morphological examination of the affected fish indicated chemical contamination, the physicochemical parameters exhibited a typical scenario of river water. For avoiding any such further incident and to precisely ascertain the cause of such fishkill episodes in future, it is suggested that a few continuous water-quality monitoring sites along Jhelum River should be set up, supplemented with robust ecological modeling simulations. Full article

Groundwater table rising (GTR) represents a well-known issue that affects several urban and agricultural areas of the world. This work addresses the link between GTR and the formation of solute plumes from contaminant sources that are located in the vadose zone, and that water table rising may help mobilize with time. A case study is analyzed in the stratified pyroclastic-alluvial aquifer near Naples (Italy), which is notoriously affected by GTR. A dismissed chemical factory generated a solute plume, which was hydraulically confined by a pump-and-treat (P&T) system. Since 2011, aqueous concentrations of 1,1-dichloroethene (1,1-DCE) have been found to exceed regulatory maximum concentration levels in monitoring wells. It has been hypothesized that a 1,1-DCE source may occur as buried waste that has been flushed with time under GTR. To elucidate this hypothesis and reoptimize the P&T system, flow and transport numerical modeling analysis was developed using site-specific data. The results indicated that the formulated hypothesis is indeed plausible. The model shows that water table peaks were reached in 2011 and 2017, which agree with the 1,1-DCE concentration peaks observed in the site. The model was also able to capture the simultaneous decrease in the water table levels and concentrations between 2011 and 2014. Scenario-based analysis suggests that lowering the water table below the elevation of the hypothesized source is potentially a cost-effective strategy to reschedule the pumping rates of the P&T system. Full article