Bioaccumulation of emerging contaminants in mussel (Mytilus galloprovincialis): Influence of microplastics

Implications of polystyrene and polyamide microplastics in the adsorption of sulfonamide antibiotics and their metabolites in water matrices

Microplastics (MP) and antibiotics coexist in the environment and their combined exposure represents a source of increasing concern. MP may act as carriers of antibiotics because of their sorption capacity. Knowledge of the interactions between them may help improve understanding of their migration and transformation. In this work, the adsorption behaviour of a group of sulfonamides and their acetylated metabolites on different sizes of polyamide (PA) and polystyrene (PS) MP were investigated and compared. Sulfonamides were adsorbed on both MP (qmax up to 0.699 and 0.184 mg/g, for PA and PS, respectively) fitting to a linear isotherm model (R2 > 0.835). A low particle size and an acidic and salinity medium significantly enhances the adsorption capacity of sulfonamides (i.e. removal of sulfamethoxazole increased from 8 % onto 3 mm PA pellets to 80 % onto 50 mm of PA pellets). According to characterization results, adsorption mechanism is explained by pore filling and hydrogen bonds (for PA) and hydrophobic interactions (for PS). After adsorption, surface area was increased in both MP as result of a potential ageing of the particles and the intensity of XRD peaks was higher denoting a MP structure more amorphized. Metabolites were adsorbed more efficiently than their parent compounds on PS while the opposite effect was observed on PA explained by the acetylation of the amine group and, subsequently the reduction of hydrogen bond interactions. Although the dissolved organic matter inhibits sulfonamides adsorption, removal up to 65.2 % in effluent wastewater and up to 72.1 % in surface water were observed in experiments using real matrices denoting the role of MP as vectors of sulfonamide antibiotics in aquatic media.

Occurrence, bioaccumulation, fate, and risk assessment of emerging pollutants in aquatic environments: A review

Significant concerns on a global scale have been raised in response to the potential adverse impacts of emerging pollutants (EPs) on aquatic creatures. We have carefully reviewed relevant research over the past 10 years. The study focuses on five typical EPs: pharmaceuticals and personal care products (PPCPs), per- and polyfluoroalkyl substances (PFASs), drinking water disinfection byproducts (DBPs), brominated flame retardants (BFRs), and microplastics (MPs). The presence of EPs in the global aquatic environment is source-dependent, with wastewater treatment plants being the main source of EPs. Multiple studies have consistently shown that the final destination of most EPs in the water environment is sludge and sediment. Simultaneously, a number of EPs, such as PFASs, MPs, and BFRs, have long-term environmental transport potential. Some EPs exhibit notable tendencies towards bioaccumulation and biomagnification, while others pose challenges in terms of their degradation within both biological and abiotic treatment processes. The results showed that, in most cases, the ecological risk of EPs in aquatic environments was low, possibly due to potential dilution and degradation. Future research topics should include adding EPs detection items for the aquatic environment, combining pollution, and updating prediction models.

Nano-scale and micron-scale plastics amplify the bioaccumulation of benzophenone-3 and ciprofloxacin, as well as their co-exposure effect on disturbing the antioxidant defense system in mussels, Perna viridis

Plastics ranging from nano-scale to micron-scale are frequently ingested by many marine animals. These particles exhibit biotoxicity and additionally perform as vectors that convey and amass adsorbed chemicals within organisms. Meanwhile, the frequency of detection of the benzophenone-3 and ciprofloxacin can be adsorbed on plastic particles, then accumulated in bivalves, causing biotoxicity. To understand their unknown accumulative kinetics in vivo affected by different plastic sizes and toxic effect from co-exposure, several scenarios were set up in which the mode organism were exposed to 0.6 mg/L of polystyrene carrying benzophenone-3 and ciprofloxacin in three sizes (300 nm, 38 μm, and 0.6 mm). The live Asian green mussels were chosen as mode organism for exposure experiments, in which they were exposed to environments with plastics of different sizes laden with benzophenone-3 and ciprofloxacin, then depurated for 7 days. The bioaccumulation and depuration kinetics of benzophenone-3 and ciprofloxacin were measured using HPLC-MS/MS after one week of exposure and depuration. Meanwhile, their toxic effect were investigated by measuring the changes in six biomarkers (condition index, reactive oxygen species, catalase, glutathione, lipid peroxidation, cytochrome P450 and DNA damage). The bioconcentration factors in mussels under different exposure conditions were 41.48-111.75 for benzophenone-3 and 6.45 to 12.35 for ciprofloxacin. The results suggested that microplastics and nanoplastics can act as carriers to increase bioaccumulation and toxicity of adsorbates in mussels in a size-dependent manner. Overproduction of reactive oxygen species caused by microplastics and nanoplastics led to increased DNA damage, lipid peroxidation, and changes in antioxidant enzymes and non-enzymatic antioxidants during exposure. Marked disruption of antioxidant defenses and genotoxic effects in mussels during depuration indicated impaired recovery. Compared to micron-scale plastic with sizes over a hundred micrometers that had little effect on bivalve bioaccumulation and toxicity, nano-scale plastic greatly enhanced the biotoxicity effect.

Evaluating quaternium-15 effects on Mytilus galloprovincialis: New insights on physiological and cellular responses

Among personal care products, quaternium-15 is prominently featured as a preservative in items such as shampoos, soaps, shaving products, and cosmetics. The widespread use of these products in people's daily routines contributes to quaternium-15 release into aquatic ecosystems. In this context, the primary aim of the study was to assess the physiological and cellular responses of the digestive gland and gills in Mytilus galloprovincialis to quaternium-15 exposure. Cell viability and the ability of digestive gland cells to regulate their volume were evaluated. Additionally, the expression of the genes involved in oxidative stress response was assessed to further substantiate the compound's harmful effects. Results indicated a significant decrease in both the viability of digestive gland cells and their RVD (regulatory volume decrease) capacity when exposed to a hypotonic solution. Furthermore, impairment of digestive gland cell function was corroborated by the modulation of oxidative stress-related gene expression, including SOD, Cat, as well as Hsp70 and CYP4Y1. Similar gene expression alterations were observed in the gills, reflecting impaired functionality in this vital organ as well. In summary, the outcomes of the study provide conclusive evidence of the toxicity of quaternium-15. This underscores the urgent need to further investigate the toxicological effects of this contaminant on aquatic ecosystems and emphasises the necessity of limiting the use of products containing quaternium-15.

Trophic transfer and interfacial impacts of micro(nano)plastics and per-and polyfluoroalkyl substances in the environment

Both micro(nano)plastics (MNPs) and per-and polyfluoroalkyl substances (PFAS) possessed excellent properties and diverse applications, albeit gained worldwide attention due to their anthropogenic, ubiquitous, degradation resistant nature and a wide variety of ecological and human health impacts. MNPs and PFAS discharged from discrete sources and extensively bioaccumulated in the food chain through trophic transfer and their long-distance transport potential assist in their dispersal to pristine but vulnerable ecosystems such as Antarctica. They inevitably interacted with each other in the environment through polarized N-H bond, hydrogen bond, hydrophobic interaction, and weak bond energies such as Van der Waals, electrostatic, and intramolecular forces. During co-exposure, they significantly impact the uptake and bioaccumulation of each other in exposed organisms, which may increase or decrease their bioavailable concentration. Hence, this review compiles the studies on the co-occurrence and adsorption of PFAS and MNPs in the environment, their trophic transfer, combined in vivo and in vitro impacts, and factors influencing the MNP-PFAS interface. A significant proportion of studies were conducted in China, Europe, and the US, while studies are rare from other parts of the world. Freshwater and marine food chains were more prominently investigated for trophic transfers compared to terrestrial food chains. The most notable in vivo effects were growth and reproductive impairment, oxidative stress, neurotoxicity and apoptosis, DNA damage, genotoxicity and immunological responses, behavioral and gut microbiota modifications, and histopathological alterations. Cellular uptake of PFAS and MNPs can impact cell survival and proliferation, photosynthesis and membrane integrity, ROS generation and antioxidant responses, and extracellular polymeric substances (EPS) release in vitro. MNP characteristics, PFAS properties, tissue and species-dependent distribution, and environmental medium properties were the main factors influencing the PFAS and MNP nexus and associated impacts. Last but not least, gaps and future research directions were highlighted to better understand the interplay between these critical persistent chemicals.

Various additive release from microplastics and their toxicity in aquatic environments

Additives may be present in amounts higher than 50% within plastic objects. Additives in plastics can be gradually released from microplastics (MPs) into the aquatic environment during their aging and fragmentation because most of them do not chemically react with the polymers. Some are known to be hazardous substances, which can cause toxicity effects on organisms and pose ecological risks. In this paper, the application of functional additives in MPs and their leaching in the environment are first summarized followed by their release mechanisms including photooxidation, chemical oxidation, biochemical degradation, and physical abrasion. Important factors affecting the additive release from MPs are also reviewed. Generally, smaller particle size, light irradiation, high temperature, dissolved organic matter (DOM) existence and alkaline conditions can promote the release of chemicals from MPs. In addition, the release of additives is also influenced by the polymer's structure, electrolyte types, as well as salinity. These additives may transfer into the organisms after ingestion and disrupt various biological processes, leading to developmental malformations and toxicity in offspring. Nonetheless, challenges on the toxicity of chemicals in MPs remain hindering the risk assessment on human health from MPs in the environment. Future research is suggested to strengthen research on the leaching experiment in the actual environment, develop more techniques and analysis methods to identify leaching products, and evaluate the toxicity effects of additives from MPs based on more model organisms. The work gives a comprehensive overview of current process for MP additive release in natural waters, summarizes their toxicity effects on organisms, and provides recommendations for future research.

Interactions between MPs and PFASs in aquatic environments: A dual-character situation

Microplastics (MPs) and per- and polyfluoroalkyl substances (PFASs) have drawn great attention as emerging threats to aquatic ecosystems. Although the literature to study the MPs and PFASs alone has grown significantly, our knowledge of the overlap and interactions between the two contaminations is scarce due to the unawareness of it. Actually, numerous human activities can simultaneously release MPs and PFASs, and the co-sources of the two are common, meaning that they have a greater potential for interactions. The direct interaction lies in the PFASs adsorption by MPs in water with integrated mechanisms including electrostatic and hydrophobic interactions, plus many influence factors. In addition, the existence and transportation of MPs and PFASs in the aquatic environment have been identified. MPs and PFASs can be ingested by aquatic organisms and cause more serious combined toxicity than exposure alone. Finally, curbing strategies of MPs and PFASs are overviewed. Wastewater treatment plants (WWTPs) can be an effective place to remove MPs from wastewater, while they are also an important point source of MPs pollution in water bodies. Although adsorption has proven to be a successful curbing method for PFASs, more technological advancements are required for field application. It is expected that this review can help revealing the unheeded relationship and interaction between MPs and PFASs in aquatic environments, thus assisting the further investigations of both MPs and PFASs as a whole.

Analytical approaches for screening of per- and poly fluoroalkyl substances in food items: A review of recent advances and improvements

Per and polyfluoroalkyl substances (PFAS) are a group of man-made chemicals characterized by their ubiquitous nature in all environmental compartments which makes them of increasing concern due to their persistence, bioaccumulation, and toxicity (PBT). Several instrumental methodologies and separation techniques have been identified in the literature for the detection and quantification of PFAS in environmental samples. In this review, we have identified and compared common separation techniques adopted for the extraction of PFAS in food items, and analytical methodologies for identification and quantification of PFAS in food items of plant and animal origin, highlighting recent advances in tandem techniques for the high selectivity and separation of PFAS related compounds as well as knowledge gaps and research needs on current analytical methodologies.

Plant -microbe assisted emerging contaminants (ECs) removal and carbon cycling

Continuous increase in the level of atmospheric CO₂ and environmental contaminates has aggravated various threats resulting from environmental pollution and climate change. Research into plant -microbe interaction has been a central concern of ecology for over the year. However, despite the clear contribution of plant -microbe to the global carbon cycle, the role of plant -microbe interaction in carbon pools, fluxes and emerging contaminants (ECs) removal are still a poorly understood. The use of plant and microbes in ECs removal and carbon cycling is an attractive strategy because microbes operate as biocatalysts to remove contaminants and plant roots offer a rich niche for their growth and carbon cycling. However, bio-mitigation of CO₂ and removal of ECs is still under research phase because of the CO₂ capture and fixation efficiency is too low for industrial purposes and cutting-edge removal methods have not been created for such emerging contaminants.

The unheeded inherent connections and overlap between microplastics and poly- and perfluoroalkyl substances: A comprehensive review

Microplastics (MPs) and poly- and perfluoroalkyl substances (PFASs) are receiving global attention due to their widespread presences and considerable level in the environment. Although the occurrence and fate of MPs and PFASs alone have been extensively studied, little was known about their unheeded connection and overlap between the two. Therefore, this review attempts to reveal it for the purpose of providing a new view from joint consideration of the two in the future studies. Initially, the critically examined data on the co-sources and existence of MPs and PFASs are summarized. Surprisingly, some products could be co-source of MPs and PFASs which are general in daily life while the distribution of the two is primary influenced by the human activity. Then, their interactions are reviewed based on the fact that PFASs can be sorbed onto MPs which are regarded as a vector of contaminations. The electrostatic interaction and hydrophobic contact are the predominant sorption mechanisms and could be influenced by environmental factors and properties of MPs and PFASs. The effects of MPs on the transport of PFASs in the environments, especially in aquatic environments are then discussed. Additionally, the current state of knowledge on the combined toxicity of MPs and PFASs are presented. Finally, the existing problems and future perspectives are outlined at the end of the review. This review provides an advanced understanding of the overlap, interaction and toxic effects of MPs and PFASs co-existing in the environment.

The effect of microplastics on the depuration of hydrophobic organic contaminants in Daphnia magna: A quantitative model analysis

Microplastics are emerging pollutants that can absorb large amounts of hydrophobic organic contaminants (HOCs). However, no biodynamic model has yet been proposed to estimate their effects on HOC depuration in aquatic organisms, where the HOC concentrations are time-varying. In this work, a microplastic-inclusive biodynamic model was developed to estimate the depuration of HOCs via ingestion of microplastics. Several key parameters of the model were redefined to determine the dynamic HOC concentrations. Through the parameterized model, the relative contributions of dermal and intestinal pathways can be distinguished. Moreover, the model was verified and the vector effect of microplastics was confirmed by studying the depuration of polychlorinated biphenyl (PCB) in Daphnia magna (D. magna) with different sizes of polystyrene (PS) microplastics. The results showed that microplastics contributed to the elimination kinetics of PCBs because of the fugacity gradient between the ingested microplastics and the biota lipids, especially for the less hydrophobic PCBs. The intestinal elimination pathway via microplastics would promote overall PCB elimination, contributing 37-41 % and 29-35 % to the total flux in the 100 nm and 2 μm polystyrene (PS) microplastic suspensions, respectively. Furthermore, the contribution of microplastic uptake to total HOC elimination increased with decreasing microplastic size in water, suggesting that microplastics may protect organisms from HOC risks. In conclusion, this work demonstrated that the proposed biodynamic model is capable of estimating the dynamic depuration of HOCs for aquatic organisms. The results can shed light on a better understanding of the vector effects of microplastics.

Exploring the Impact of Contaminants of Emerging Concern on Fish and Invertebrates Physiology in the Mediterranean Sea

In this historical context, the Mediterranean Sea faces an increasing threat from emerging pollutants such as pharmaceuticals, personal care products, heavy metals, pesticides and microplastics, which pose a serious risk to the environment and human health. In this regard, aquatic invertebrates and fish are particularly vulnerable to the toxic effects of these pollutants, and several species have been identified as bio-indicators for their detection. Among these, bivalve molluscs and elasmobranchs are now widely used as bio-indicators to accurately assess the effects of contaminants. The study focuses on the catshark Scyliorhinus canicular and on the Mediterranean mussel Mytilus galloprovincialis. The first one is a useful indicator of localised contamination levels due to its exposure to pollutants that accumulate on the seabed. Moreover, it has a high trophic position and plays an important role in the Mediterranean Sea ecosystem. The bivalve mollusc Mytilus galloprovincialis, on the other hand, being a filter-feeding organism, can acquire and bioaccumulate foreign particles present in its environment. Additionally, because it is also a species of commercial interest, it has a direct impact on human health. In conclusion, the increasing presence of emerging pollutants in the Mediterranean Sea is a serious issue that requires immediate attention. Bivalve molluscs and elasmobranchs are two examples of bio-indicators that must be used to precisely determine the effects of these pollutants on the marine ecosystem and human health.

Baseline levels of integrated biomarker response index (IBR) in Mytilus galloprovincialis (Lamarck, 1819) of BouIsmail bay for monitoring Algerian Bays (Mediterranean Sea)

The Multiple Linear Regression (MLR) technique was used to determine the relationship between the integrated biomarker response index (IBR) with the most important confounding factors (Temperature, pH, Salinity and Dissolved oxygen), in order to define: (1) the baseline assessment criteria (BAC), (2) the environmental assessment criteria (EAC) and (3) the BouIsmail Bay (BIB) -Taxonomy by using Mytilus galloprovincialis sampled from two references sites in BIB (W. Tipaza, Algeria) during one season. Therefore, our results show that, the temperature appeared as a major factor for the explanation of the model. The coefficients of determination and F values for IBR validated the efficiency of model. In addition, the use MLR, BAC and EAC values in BIB-Taxonomy can deference between unpolluted and polluted areas in BouIsmail Bay in particular and Algerian Bays in general. This approach is therefore a valuable tool that could be used for monitoring the coastal sites.

Filtration of biopolymer PHB particles loaded with synthetic musks does not cause significant bioaccumulation in marine mussels

The role of the biopolymer polyhydroxybutyrate (PHB, <250 µm) as a vehicle of a synthetic musks mixture (celestolide, galaxolide, tonalide, musk xylene, musk moskene and musk ketone) to Mytilus galloprovincialis was investigated. For 30 days, virgin PHB, virgin PHB+musks (6.82 µg g-1) and weathered PHB+musks, were daily spiked into tanks containing mussels, followed by a 10-day depuration period. Water and tissues samples were collected to measure exposure concentrations and accumulation in tissues. Mussels were able to actively filter microplastics in suspension but the concentration of the musks found in tissues (celestolide, galaxolide, tonalide) were markedly lower than the spiked concentration. Estimated Trophic Transfer Factors suggest that PHB will only play a minor role on musks accumulation in marine mussels, even if our results suggest a slightly extended persistence in tissues of musks loaded to weathered PHB.

Bioaccumulation/bioconcentration of pharmaceutical active compounds in aquatic organisms: Assessment and factors database

There is increasing evidence that the presence of certain pharmaceuticals in the environment leads to biota exposure and constitute a potential risk for ecosystems. Bioaccumulation is an essential focus of risk assessment to evaluate at what degree emerging contaminants are a hazard both to the environment and the individuals that inhabit it. The main goals of the present review are 1) to summarize and describe the research and factors that should be taken into account in the evaluation of bioaccumulation of pharmaceuticals in aquatic organisms; and 2) to provide a database and a critical review of the bioaccumulation/bioconcentration factors (BAF or BCF) of these compounds in organisms of different trophic levels. Most studies fall into one of two categories: laboratory-scale absorption and purification tests or field studies and, to a lesser extent, large-scale, semi-natural system tests. Although in the last 5 years there has been considerable progress in this field, especially in species of fish and molluscs, research is still limited on other aquatic species like crustaceans or algae. This revision includes >230 bioconcentration factors (BCF) and >530 bioaccumulation factors (BAF), determined for 113 pharmaceuticals. The most commonly studied is the antidepressant group, followed by diclofenac and carbamazepine. There is currently no reported accumulation data on certain compounds, such as anti-cancer drugs. BCFs are highly influenced by experimental factors (notably the exposure level, time or temperature). Field BAFs are superior to laboratory BCFs, highlighting the importance of field studies for reliable assessments and in true environmental conditions. BAF data appears to be organ, species and compound-specific. The potential impact on food web transfer is also considered. Among different aquatic species, lower trophic levels and benthic organisms exhibit relatively higher uptake of these compounds.

The interaction mechanism of polystyrene microplastics with pharmaceuticals and personal care products

Microplastics (MPs) have been detected in the hydrosphere, with hazardous implications in transporting coexisting water pollutants. Our knowledge about the interaction mechanisms that MPs establish with organic pollutants are still growing, which is essential to understand the adsorption properties of MPs and their relative stability with adsorbates. Here, we used classical (force field methods) and ab-initio (density functional theory) computational chemistry tools to characterize the interaction mechanisms between Polystyrene-MPs (PS-MPs) and pharmaceuticals/personal care products (PPCPs). Adsorption conformations and energies, thermochemistry, binding, and energy decomposition analyses were performed to obtain the quantitative mechanistic information. Our results show that PS-MPs have permanent dipoles, increasing the interaction with neutral PPCPs while repelling the charged pollutants; in all cases, a stable physisorption takes place. Moreover, PS-MPs increase their solubility upon pollutant adsorption due to an increase in the dipole moment, increasing their co-transport ability in aqueous environments. The stability of the PS-MPs/PPCPs complexes is further confirmed by thermochemical and molecular dynamics trajectory analysis as a function of temperature and pressure. The interaction mechanism of high pKa pollutants (pKa > 5) is due to a balanced contribution of electrostatic and dispersion forces, while the adsorption of low pKa pollutants (pKa < 5) maximizes the electrostatic forces, and steric repulsion effects explain their relative lower adsorption stability. In this regard, several pairwise intermolecular interactions are recognized as a source of stabilization in the PS-MPs/PPCPs binding: hydrogen bonding, π-π, OH⋯π, and CH⋯π, CCl⋯CH and CH⋯CH interactions. The ionic strength in solution slightly affects the adsorption stability of neutral PPCPs, while the sorption of charged pollutants is enhanced. This mechanistic information provides quantitative data for a better understanding of the interactions between organic pollutants and MPs, serving as valuable information for sorption/kinetic studies.

Elucidating the consequences of the co-exposure of microplastics jointly to other pollutants in bivalves: A review

The marine environment has numerous impacts related to anthropogenic activities including pollution. Abundances of microplastics (MPs) and other pollutants are continuously increasing in the marine environment, resulting in a complex mixture of contaminants affecting biota. In order to understand the consequences, a review of studies analyzing combined effects of MPs and other types of pollutants in bivalves has been conducted as species in this group have been considered as sentinel and bioindicators. Regarding studies reviewed, histological analyses give evidence that MPs can be located in the haemolymph, gills and gonads, as well as in digestive glands in the intestinal lumen, epithelium and tubules, demonstrating that the entire body of bivalves is affected by MPs. Moreover, DNA strand breaks represent the most relevant form of damage caused by the enhanced production of reactive oxygen species in response to MPs exposure. The role of MPs as vectors of pollutants and the ability of polymers to adsorb different compounds have also been considered in this review highlighting a high variability of results. In this sense, toxic impacts associated to MPs exposure were found to significantly increase with the co-presence of antibiotics or petroleum hydrocarbons amongst other pollutants. In addition, bioaccumulation processes of pollutants (PAHs, metals and others) have been affected by the co-presence with MPs. Histological, genetic and physiological alterations are the most reported damages, and the degree of harm seems to be correlated with the concentration and size of MP and with the type of pollutant.

Adsorption of perfluoroalkyl substances on polyamide microplastics: Effect of sorbent and influence of environmental factors

Microplastics (MPs) and perfluoroalkyl substances (PFASs) are two types of pollutants coexisting in the environment. Their co-exposure is a source of increasing concern. MPs present in the natural environment suppose an ideal surface for the sorption of hazardous contaminants. This study investigates the adsorption behaviour of six PFASs on polyamide (PA) MPs. Adsorption experiments under various internal (PA and PFASs dosage, PA particle size) and environmental (pH, ionic strength, dissolved organic matter) factors were carried out. Isotherm results (from 0.1 to 25 mg/L of PFASs) showed that the maximum adsorption capacity of the selected PFASs on the PA was as follows: perfluorooctanesulfonic acid (PFOS, 0.873 mg/g) > perfluorooctanoic acid (0.235 mg/g) > perfluoroheptanoic acid (0.231 mg/g) > perfluorohexanoic acid (0.201 mg/g) > perfluoropentanoic acid (0.192 mg/g) > perfluorobutanoic acid (0.188 mg/g) (pH 5.88, 0% salinity and 0% of dissolved organic matter). The PFOS has more tendency to be sorbed onto PA than perfluorocarboxilic acids. The MP characterization by scanning electron microscopy, X ray diffraction and Fourier transform infrared spectroscopy showed changes in the PA surface after adsorption assays. Pore filling, hydrophobic interactions and hydrogen bonds governed sorption process. The sorption capacity of PFASs was crucially affected by the PA size (from 19.6% to 99.9% for 3 mm and 50 μm particle size, respectively). The process was not significantly influenced by salinity while the dissolved organic matter exerted a negative effect (decrease from 100% to 26% for PFOS in presence of 25 mg/L of humic acid). Finally, adsorption rates of PFASs were quantified in real water matrices (influent and effluent wastewater, surface and tap water samples). The results revealed interactions between PA and PFASs and evidenced the role of PA as a vector to transport PFASs in the aquatic environment.

The burden of emerging contaminants upon an Atlantic Ocean marine protected reserve adjacent to Camps Bay, Cape Town, South Africa

The presence and levels of fifteen chemicals of emerging concerns, including five perfluorinated compounds (PFCs), two industrial chemicals, seven pharmaceuticals and one personal care product, were evaluated in biota, seawater and sediments obtained from near-shore coastal zone in Camps Bay, Cape Town, South Africa. Eight compounds were found in seawater, and between nine to twelve compounds were quantified in marine invertebrates, sediment and seaweed. Diclofenac was the prevalent pharmaceutical with a maximum concentration of 2.86 ng/L in seawater, ≥110.9 ng/g dry weight (dw) in sediments and ≥67.47 ng/g dw in marine biotas. Among PFCs, perfluoroheptanoic acid was predominant in seawater (0.21-0.46 ng/L). Accumulation of perfluorodecanoic acid (764 ng/g dw) as well as perfluorononanoic acid and perfluorooctanoic acid (504.52 and 597.04 ng/g dw, respectively) was highest in samples of seaweed. The environmental risk assessment carried out in this study showed that although individual pollutants pose a low acute and chronic risk, yet individual compounds each had a high bioaccumulation factor in diverse marine species, and their combination as a complex mixture in marine organisms might have adverse effects upon aquatic organisms. Data revealed that this Atlantic Ocean marine protected environment is affected by the presence of numerous and diverse emerging contaminants that could only have originated from sewage discharges. The complex mixture of persistent chemicals found bioaccumulating in marine organisms could bode ill for the propagation and survival of marine protected species, since many of these compounds are known toxicants.

Digestion of plastics using in vitro human gastrointestinal tract and their potential to adsorb emerging organic pollutants

Excessive plastic use has inevitably led to its consumption by organisms, including humans. It is estimated that humans consume 20 kg of plastic during their lifetime. The presence of microplastics in the human body can carry serious health risks, such as biological reactions e.g. inflammation, genotoxicity, oxidative stress, apoptosis, as well toxic compounds leaching of unbound chemicals/monomers, free radicals or adsorbed organic pollutants, which mainly depend on the properties of the ingested plastic. Plastics are exposed to different substances (e.g., enzymes and acids) in the digestive system, which potentially affects their properties and structure. By stimulating the human digestive system and applying a set of advanced analytical tools, we showed that the surface of polystyrene and high-density polyethylene plastics frequently in contact with food undergoes fundamental changes during digestion. This results in the appearance of additional functional groups, and consequent increase in the plastic adsorption capacity for hydrophobic ionic compounds (such as triclosan and diclofenac) while reducing its adsorption capacity for hydrophobic non-ionic compounds (such as phenanthrene). Micro- and nanostructures that formed on the flat surface of the plastics after digestion were identified using scanning electron microscopy. These structures became defragmented and detached due to mechanical action, increasing micro- and nanoplastics in the environment. Due to their size, the release of plastic nanostructures after digestion can become an "accidental food source" for a wider group of aquatic organisms and ultimately for humans as the last link in the food chain. This, combined with improved adsorption capacity of digested plastics to hydrophobic ionic pollutants, can pose a serious threat to the environment including human health and safety.

Aging of microplastics increases their adsorption affinity towards organic contaminants

When released in the environment, microplastics undergo surface weathering due to mechanical abrasion and ultraviolet exposure. In this study, the adsorption of two model contaminants, phenanthrene and methylene blue, by weathered high density polyethylene (HDPE) and polypropylene (PPE) was evaluated to understand how the microplastics' aging influences contaminant adsorption. Microplastics were aged through an accelerated weathering process using ultraviolet exposure with or without hydrogen peroxide. Adsorption isotherms were conducted for both contaminants on pristine and aged microplastics. The adsorption of organic contaminants was higher on aged microplastics than on pristine ones, with methylene blue having the highest affinity increase with aging at 4.7-fold and phenanthrene having a 1.9-fold increase compared to the pristine particles. To understand the mechanisms involved with higher adsorption of contaminants by aged microplastics, changes in the specific surface area and surface chemistry of aged microplastics were characterized by Fourier Transform Infrared Spectroscopy, X-ray Photoelectron Spectroscopy, zeta potential, X-ray tomography, and Brunauer-Emmett-Teller krypton adsorption analyses. The results of this study show that oxidation of microplastics can enhance the adsorption of organic contaminants, which may increase their role as vectors of contaminants in the aquatic food chain.

The polymers and their additives in particulate plastics: What makes them hazardous to the fauna?

Due to the increasing concerns on global ecosystems and human health, the environmental risks posed by microplastics (MPs) and nanoplastics (NPs) have become an important topic of research. Their ecological impacts on various faunal species have been extensively researched and reviewed. However, the majority of those studies perceive these micro(nano)-plastics (MNPs) as a single entity rather than a collective term for a group of chemically distinct polymeric particulates. Each of the plastic polymers can possess unique physical and chemical behavior, which, in turn, can determine the possible environmental impacts. Furthermore, many studies explore the adsorption, absorption, and release of other environmental pollutants by MNPs. But only a handful of them explore the leaching of additives possessed by these polymers. Data on the environmental behavior and toxicity of individual additives associated with different polymer particulates are scarce. Knowledge about the leachability and ecotoxicity of the additives associated with environmental MNPs (unlike large plastic particles) remains limited. The ecological impacts of different MNPs together with their additives and the basis of their toxicity have not been explored yet. The present review systematically explores the potential implications of environmentally predominant polymers and their associated additives and discusses their physicochemical characteristics. The review ultimately aims to provide novel insights on what components precisely make MNPs hazardous to the fauna. The paper also discusses the major challenges proposed in the available literature along with recommendations for future research to throw light on possible solutions to overcome the hazards of MNPs.

Ultrasound-assisted extraction as an easy-to-perform analytical methodology for monitoring ibuprofen and its main metabolites in mussels

Non-steroidal anti-inflammatory drugs (NSAIDs) have been reported to be the main pharmaceutical class accumulated in seafood. Among them, ibuprofen (IBU) is of special concern as it is used worldwide to treat common pain, does not require a medical prescription, it is often taken in a high daily dose, and has been reported to cause potential adverse effects on aquatic organisms. IBU is highly transformed into hydroxy- and carboxy-metabolites and/or degradation products generated not only after its administration but also during wastewater treatment or in the environment. These compounds can be present in the environment at higher concentrations than IBU and present higher toxicity. In this work, a low-cost and affordable routine analytical method was developed and validated for the first-time determination of IBU and its main metabolites in mussels. The method is based on ultrasound-assisted extraction (UAE), clean-up by dispersive solid-phase extraction (d-SPE) and analytical determination by liquid chromatography-tandem mass spectrometry. Box-Behnken experimental design was used for method optimisation to better evaluate the influence and interactions of UAE and d-SPE variables. Extraction recoveries were in the range from 81 to 115%. Precision, expressed as relative standard deviation, was lower than 7%. Method detection limits were in the range from 0.1 to 1.9 ng g⁻¹ dry weight. The method was successfully applied to wild mussels.

Occurrence of bisphenols and benzophenone UV filters in wild brown mussels (Perna perna) from Algoa Bay in South Africa

Bisphenols and benzophenone UV filters are contaminants present in a wide variety of plastic materials and consumer products. The scientific attention towards these contaminants has increased in recent years due to their presence in microplastics, their ubiquitous occurrence in the environment, and their known endocrine disrupting health effects. In this study, the occurrence of nine bisphenol and five benzophenone UV-filter analogues was assessed in wild brown mussels (Perna perna) collected from different sampling sites along the coast of Algoa Bay, South Africa. Eleven out of fourteen target analytes were detected, and bisphenol AP (BPAP) was detected for the first time in mussels, presenting the highest median concentration of 150 ng g^-1 dry weight (d.w.) and a detection frequency of 91%. Regarding benzophenone UV-filters, median concentrations of the analogues (across all sites) ranged from 2.01 to 10.6 ng g^-1 d.w., with benzophenone-1 (BzP-1) and benzophenone-3 (BzP-3) presenting the highest concentrations. Human exposure was assessed by estimating daily intakes (EDI) of the target analytes through mussel consumption. To our knowledge, this is the first study from the African continent on the occurrence of bisphenols and benzophenone UV-filters in a large population (n=138) of wild brown mussels.