An overview on metal pollution on touristic sandy beaches: Is the COVID-19 pandemic an opportunity to improve coastal management?

The worldwide spread of the SARS-CoV-2 caused an unprecedented lockdown measures in most countries with consequences on the world society, economy, and sanitary systems. This situation provided an opportunity to identify the effects of human confinement on natural environments, like touristic sandy beaches, which are stressed due to anthropogenic pressures. Based on previous articles about heavy metals sources and levels in these ecosystems, this paper discusses the dynamic of these pollutants and a regulatory scenario associated with COVID-19 sanitation policies. The main findings suggest that 39% of the studies were on Asian sandy beaches, 16% from Europe, while America and Africa with 23% each. Also Co, Cd, Cu, Cr, Zn, Pb, Ni, Fe and Mn were the most frequently analyzed metals in sediments and in several cases their concentrations exceed international guidelines assessment. Finally, even though beaches are under several metals inputs, tourism plays a key role in these ecosystems quality. After analyzing the potential indirect effect of COVID-19 measures on metals dynamics, we propose some key recommendations and management strategies to mitigate heavy metal pollution on sandy tourist beaches. These proposals are useful for decision-makers and stakeholders to improve sandy beach management, mainly those beaches not addressed from a management perspective; and their implementation should be adapted according to the regulations and legislation of each country.

Critical review of the characteristics, interactions, and toxicity of micro/nanomaterials pollutants in aquatic environments.

A wide range of contaminants of emerging concern such as micro/nanoplastics (MPs/PNPs) and metal-nanoparticles (Me-NPs) from anthropogenic activities have been identified in aquatic environments. The hazardous effects of these micro/nanomaterials as pollutants in organisms and the lack of knowledge about their behavior in aquatic environments have generated growing concern in the scientific community. The nanomaterials have a colloidal-type behavior due to their size range but with differences in their physicochemical properties. This review comprises the behavior of micro/nanomaterials pollutants and the physicochemical interactions between MPs/PNPs and Me-NPs in aquatic environments, and their potential toxicological effects in organisms. Moreover, this article describes the potential use of Me-NPs to remove MPs/PNPs present in the water column due to their photocatalytic and magnetic properties. It also discusses the challenge to determine harmful effects of micro/nanomaterials pollutants in organisms and provides future research directions to improve integrated management strategies to mitigate their environmental impact.

Microplastics in bivalves, water and sediments from a touristic sandy beach of Argentina.

This study assesses for the first time the concentrations of microplastics (MPs) in sediments, water and two human-consumed mussels with different ecological traits (Amarilladesma mactroides and Brachidontes rodriguezii) in a touristic sandy beach of Argentina. MPs were characterized through FTIR and SEM/EDX techniques. All the samples presented MPs with similar concentrations as other human-impacted coastal areas of the world, being black and blue fibers of < 0.5 and 0.5-1 mm the most abundant. SEM images exhibited cracks and fractures with clay minerals and microorganisms adhered to MPs surface. EDX spectrums showed potentially toxic elements, such as Cr, Ti, and Mo. FTIR identified polymers such as cellulose, polyamides, and polyacrylates in most of the samples analyzed. Our study demonstrates that microplastic pollution is a common threat to sandy beaches in Argentina, worsened by plastic particles carrying metal ions with potential toxic effects to the biota, including A. mactroides, an endangered species.