Nanoparticles as vectors of other contaminants in estuarine suspended sediments: Natural and real conditions

Vanadium in the Environment: Biogeochemistry and Bioremediation

Vanadium(V) is a highly toxic multivalent, redox-sensitive element. It is widely distributed in the environment and employed in various industrial applications. Interactions between V and (micro)organisms have recently garnered considerable attention. This Review discusses the biogeochemical cycling of V and its corresponding bioremediation strategies. Anthropogenic activities have resulted in elevated environmental V concentrations compared to natural emissions. The global distributions of V in the atmosphere, soils, water bodies, and sediments are outlined here, with notable prevalence in Europe. Soluble V(V) predominantly exists in the environment and exhibits high mobility and chemical reactivity. The transport of V within environmental media and across food chains is also discussed. Microbially mediated V transformation is evaluated to shed light on the primary mechanisms underlying microbial V(V) reduction, namely electron transfer and enzymatic catalysis. Additionally, this Review highlights bioremediation strategies by exploring their geochemical influences and technical implementation methods. The identified knowledge gaps include the particulate speciation of V and its associated environmental behaviors as well as the biogeochemical processes of V in marine environments. Finally, challenges for future research are reported, including the screening of V hyperaccumulators and V(V)-reducing microbes and field tests for bioremediation approaches.

Potential impacts of titanium dioxide nanoparticles on trace metal speciation in estuarine sediments

Engineered titanium dioxide (TiO₂) nanoparticles (NPs) are widely used and consequently released into the environment. The subsequent accumulation of TiO₂ NPs in depositional environments may affect the geochemical behavior of trace metals, which needs to be assessed. Here, we performed experiments to investigate the speciation change for molybdenum and tungsten in the presence of TiO₂ NPs. Laboratory results show that the rate constant for MoS₄^2- hydrolysis associated with TiO₂ NPs is ~1.75 × 10^-9 L m^-2 s^-1, whereas it is 5.95 × 10^-10 L m^-2 s^-1 for WS₄^2- hydrolysis. In addition, we estimated the maximum rate for MoS₄^2- hydrolysis to be ~1.24 × 10^-1 μM hr^-1, whereas the maximum rate for WS₄^2- hydrolysis is ~4.91 × 10^-2 μM hr^-1. However, the modeling results suggest that the TiO₂ NPs accumulated in estuarine sediments might play a relatively minor role in affecting the speciation of trace metals prior to the current time. This is because the relatively low accumulation (i.e., < 8 × 10^-3 mol kg^-1) of TiO₂ NPs before 2021 results in the lower rate (>100 times) for speciation changes of both molybdenum and tungsten compared to the rate for natural geochemical processes. On the other hand, our results suggest that TiO₂ NPs will likely impact the oxyanion cycling in the near future owing to the increasing accumulations of TiO₂ NPs in estuarine sediments.

Hazardous elements present in coal nanoparticles in a Caribbean port region in Colombia

Scientific works examining coal-derived nanoparticles (NPs) containing potentially toxic elements (PTEs) confined in marine suspended sediments (MSSs) in port regions worldwide is an understudied topic, despite the fact that coal NPs have tremendous negative impacts on marine estuaries. The general objective of this study is to analyze the NP levels of coal, including PTEs, contained within MSSs in the general vicinity of the largest Caribbean port in Colombia. The morphology, size, chemical composition, and agglomeration states of NPs within MSSs of the sampled beaches were calculated through modern electron microscopy. The methodology used to detect chemical elements, unfortunately with EDS, it is not possible to precisely specify the chemical elements of low atomic weight (e.g. H, O, F, etc.) Therefore, with the EDS available today, it is only possible to have an idea of the chemical composition of each detected particle. Thus, it was possible to obtain the average frequency of the chemical elements identified in the 23 analyzed sampling points. Through the results, more than one thousand particles were detected in the most abundant phases, thus, the most frequent particles in the results of this manuscript were described. Sample point 8, located closest to the coal export port, had a higher concentration of nano-toxic elements (Al, Fe, Si, K, Mg, K) most concerning for human health in addition to being harmful to marine life. This study suggests that public policies dealing with MSS pollution need to be discussed by public managers to avoid further and sustained environmental degradation. The need to create projects will subsidize legacy liabilities generated by coal in seaports in other regions of the world.

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.

Indoor Nanoparticle Characterization in Construction Waste Recycling Companies over Time

Building activity is a significant source of atmospheric contamination by ultrafine dust. Cognizant of this fact, those active in the use and recycling of construction materials must be aware of the risks associated with exposure to nanoparticles (NPs) and ultra-fine particles (UFPs), as well as the associated health impacts. This work analyzed NPs and UFPs generated in a small building-material recycling company using high-resolution electron microscopes and X-ray Diffraction. A self-made passive sampler (LSPS) that can obtain particulate samples without physical and morphological changes, especially where there is a suspension of particulate material, was used in this study. A total of 96 particulate samples, using the LSPS for three months in four seasons, were collected during the study. Thus, the dry deposition of the particles, which are considered highly harmful to human health, was found in each of the four seasons of the year. It is suggested that for future research, the toxicological evaluations of the particulates in the construction industry should be investigated through the consideration of measures to control and mitigate the health risks of workers regarding exposure to NPs and UFPs.

Biophysical matter in a marine estuary identified by the Sentinel-3B OLCI satellite and the presence of terrestrial iron (Fe) nanoparticles

The analysis of marine matter using the Sentinel-3B OLCI (Ocean Land Color Instrument) satellite is the most advanced technique for evaluating: the absorption of colored detrital and dissolved material (ADG_443_NN), total suspended matter concentration (TSM_NN) and of chlorophyll-a (CHL_NN) on a global scale. The objective is to analyze ADG_443_NN, TSM_NN and CHL_NN using the Sentinel-3B OLCI satellite and the presence of Fe-nanoparticles (NPs) + hazardous elements (HEs) in suspended sediments (SSs) in the maritime estuary of the Colombian city of Barranquilla. The study used the unpublished image of the Sentinel-3B OLCI satellite in the evaluation of ADG_443_NN, TSM_NN and CHL_NN in 72 sampled points. Subsequently, 36 samples of SSs were carried out in the Magdalena River, in the identification of Fe-NPs by advanced electron microscopies. The Sentinel-3B satellite revealed particulate accumulations in OCE1 through the intensity of OLCI in ocean. There was also a high Fe-NPs intensity of SSs in the Magdalena channel, spreading contamination to large regions.