Acute and long-term effects of anionic polyacrylamide (APAM) on different developmental stages of two marine copepod species

Effects of petrogenic pollutants on North Atlantic and Arctic Calanus copepods: From molecular mechanisms to population impacts

Oil and gas industries in the Northern Atlantic Ocean have gradually moved closer to the Arctic areas, a process expected to be further facilitated by sea ice withdrawal caused by global warming. Copepods of the genus Calanus hold a key position in these cold-water food webs, providing an important energetic link between primary production and higher trophic levels. Due to their ecological importance, there is a concern about how accidental oil spills and produced water discharges may impact cold-water copepods. In this review, we summarize the current knowledge of the toxicity of petroleum on North Atlantic and Arctic Calanus copepods. We also review how recent development of high-quality transcriptomes from RNA-sequencing of copepods have identified genes regulating key biological processes, like molting, diapause and reproduction in Calanus copepods, to suggest linkages between exposure, molecular mechanisms and effects on higher levels of biological organization. We found that the available ecotoxicity threshold data for these copepods provide valuable information about their sensitivity to acute petrogenic exposures; however, there is still insufficient knowledge regarding underlying mechanisms of toxicity and the potential for long-term implications of relevance for copepod ecology and phenology. Copepod transcriptomics has expanded our understanding of how key biological processes are regulated in cold-water copepods. These advances can improve our understanding of how pollutants affect biological processes, and thus provide the basis for new knowledge frameworks spanning the effect continuum from molecular initiating events to adverse effects of regulatory relevance. Such efforts, guided by concepts such as adverse outcome pathways (AOPs), enable standardized and transparent characterization and evaluation of knowledge and identifies research gaps and priorities. This review suggests enhancing mechanistic understanding of exposure-effect relationships to better understand and link biomarker responses to adverse effects to improve risk assessments assessing ecological effects of pollutant mixtures, like crude oil, in Arctic areas.

Water-Soluble Synthetic Polymers: Their Environmental Emission Relevant Usage, Transport and Transformation, Persistence, and Toxicity

Water-soluble synthetic polymers (WSPs) are distinct from insoluble plastic particles, which are both critical components of synthetic polymers. In the history of human-made macromolecules, WSPs have consistently portrayed a crucial role and served as the ingredients of a variety of products (e.g., flocculants, thickeners, solubilizers, surfactants, etc.) commonly used in human society. However, the environmental exposures and risks of WSPs with different functions remain poorly understood. This paper provides a critical review of the usage, environmental fate, environmental persistence, and biological consequences of multiple types of WSPs in commercial and industrial production. Investigations have identified a wide market of applications and potential environmental threats of various types of WSPs, but we still lack the suitable assessment tools. The effects of physicochemical properties and environmental factors on the environmental distribution as well as the transport and transformation of WSPs are further summarized. Evidence regarding the degradation of WSPs, including mechanical, thermal, hydrolytic, photoinduced, and biological degradation is summarized, and their environmental persistence is discussed. The toxicity data show that some WSPs can cause adverse effects on aquatic species and microbial communities through intrinsic toxicity and physical hazards. This review may serve as a guide for environmental risk assessment to help develop a sustainable path for WSP management.

Bioaerogels, the emerging technology for wastewater treatment: A comprehensive review on synthesis, properties and applications

Over the past decade use of aerogels has received much attention as an emerging technology for wastewater treatment. However, production of aerogels is not environment-friendly. Owing to its excellent properties such as porosity, three-dimensional structure, being amenable to chemical modifications, it is imperative to devise strategies for their improved production and use. Bioaerogels are non-toxic and most of their precursor compounds are biomass-derived. This review aims to present a comprehensive report on survey of existing literature published on the use of bioaerogels for removal of all major categories of water contaminants, namely, heavy metals, industrial dyes, oil, organic compounds and pharmaceuticals. It also gives critical analysis of the lacunae in the existing knowledge such as lack of studies on domestic sewage, emerging pollutants, toxicity of raw materials and adequate disposal of used adsorbents. Proposals of overcoming the limitations in the applicability of bioaerogels, like combining constructed wetlands with use of bioaerogels, among others have been discussed. In this review, emphasis has been given on production of bioaerogels, with an aim to underscore the potential of valorization of biomass waste to develop novel materials for wastewater treatment in an effort towards creating a circular and green economy.

Tailored Leaching Tests as a Tool for Environmental Management of Mine Tailings Disposal at Sea

The expanding human activities in coastal areas increase the need for developing solutions to limit impacts on the marine environment. Sea disposal affects the marine environment, but despite the growing knowledge of potential impacts, there are still no standardized leaching tests for sea disposal. The aim of this study was to contribute to the development of leaching tests, exemplified using mine tailings, planned for submarine disposal in the Repparfjord, Norway. The mine tailings had elevated concentrations of Ba, Cr, Cu, Mn and Ni compared to background concentrations in the Repparfjord. Variables known to affect metal leaching in marine environments (DOC, pH, salinity, temperature, aerated/anoxic) were studied, as was the effect of flocculant (Magnafloc10), planned to be added prior to discharge. Stirred/non-stirred setups simulated the resuspension and disposal phases. Leaching of metals was below 2% in all experiments, with the highest rate observed for Cu and Mn. Multivariate analysis revealed a different variable importance for metals depending on their association with minerals. Higher leaching during resuspension than disposal, and lower leaching with the addition of Magnafloc10, especially for Cu and Mn, was observed. The leaching tests performed in this study are transferable to other materials for sea disposal.

Spotlight on the Life Cycle of Acrylamide-Based Polymers Supporting Reductions in Environmental Footprint: Review and Recent Advances

Humankind is facing a climate and energy crisis which demands global and prompt actions to minimize the negative impacts on the environment and on the lives of millions of people. Among all the disciplines which have an important role to play, chemistry has a chance to rethink the way molecules are made and find innovations to decrease the overall anthropic footprint on the environment. In this paper, we will provide a review of the existing knowledge but also recent advances on the manufacturing and end uses of acrylamide-based polymers following the "green chemistry" concept and 100 years after the revolutionary publication of Staudinger on macromolecules. After a review of raw material sourcing options (fossil derivatives vs. biobased), we will discuss the improvements in monomer manufacturing followed by a second part dealing with polymer manufacturing processes and the paths followed to reduce energy consumption and CO2 emissions. In the following section, we will see how the polyacrylamides help reduce the environmental footprint of end users in various fields such as agriculture or wastewater treatment and discuss in more detail the fate of these molecules in the environment by looking at the existing literature, the regulations in place and the procedures used to assess the overall biodegradability. In the last section, we will review macromolecular engineering principles which could help enhance the degradability of said polymers when they reach the end of their life cycle.