Can coastline plant species be used as biosamplers of emerging contaminants? - UV-filters and synthetic musks as case studies

Emerging organic contaminants in the soil-plant-receptor continuum: transport, fate, health risks, and removal mechanisms

There is a lack of comprehensive reviews tracking emerging organic contaminants (EOCs) within the soil-plant continuum using the source-pathway-receptor-impact-mitigation (SPRIM) framework. Therefore, this review examines existing literature to gain insights into the occurrence, behaviour, fate, health hazards, and strategies for mitigating EOCs within the soil-plant system. EOCs identified in the soil-plant system encompass endocrine-disrupting chemicals, surfactants, pharmaceuticals, personal care products, plasticizers, gasoline additives, flame retardants, and per- and poly-fluoroalkyl substances (PFAS). Sources of EOCs in the soil-plant system include the land application of biosolids, wastewater, and solid wastes rich in EOCs. However, less-studied sources encompass plastics and atmospheric deposition. EOCs are transported from their sources to the soil-plant system and other receptors through human activities, wind-driven processes, and hydrological pathways. The behaviour, persistence, and fate of EOCs within the soil-plant system are discussed, including sorption, degradation, phase partitioning, (bio)transformation, biouptake, translocation, and bioaccumulation in plants. Factors governing the behaviour, persistence, and fate of EOCs in the soil-plant system include pH, redox potential, texture, temperature, and soil organic matter content. The review also discusses the environmental receptors of EOCs, including their exchange with other environmental compartments (aquatic and atmospheric), and interactions with soil organisms. The ecological health risks, human exposure via inhalation of particulate matter and consumption of contaminated food, and hazards associated with various EOCs in the soil-plant system are discussed. Various mitigation measures including removal technologies of EOCs in the soil are discussed. Finally, future research directions are presented.

Effects of TiO2 ultraviolet filter and sunscreens on coastal dune plant performance and competitive interactions

Ultraviolet filters (UVFs) added to sunscreens (SS) are emerging contaminants in marine environments due to their adverse effects on organisms and ecosystems. UVFs have also been detected in beach-dune systems, but their influence on resident organisms has not been explored yet. Native plants are fundamental components of coastal dunes, and these ecologically/economically important systems are currently among the most threatened globally. Thus, understanding whether UVFs may act as threats to dune plants is crucial. This field study evaluated and compared the effects of titanium dioxide nanoparticles (nTiO2), one of the inorganic UVFs most commonly added to sunscreens, and those of a commercial sunscreen product containing it (SS-nTiO2) on the performance of adult dune plants of a native (Thinopyrum junceum) and a non-native invasive species (Carpobrotus sp. pl.) and their competitive interactions at environmentally realistic concentrations. The effects of nTiO2, SS-nTiO2 and of a sunscreen product containing just organic UVFs (SS-OF) on early life stages of T. junceum were also examined. Ti bulk content in sand and plants at the study site ranged from 970 to 1069 mg kg-1 and from 2 to 7.9 mg kg-1, respectively. Thinopyrum junceum adult plants periodically exposed during the summer season to seawater contaminated by SS-nTiO2 produced less biomass than un-exposed plants and nTiO2 exposed plants. nTiO2 and SS-nTiO2 reduced the capacity of T. junceum to control the spread of Carpobrotus. Both SS-nTiO2 and SS-OF reduced seedling emergence in T. junceum whereas nTiO2 did not. These results demonstrated that the periodical exposures of native dune plants to sunscreens could reduce their establishment success and growth and favor invasive plant spread potentially resulting in community structure changes. They also emphasize the need to assess the phytotoxicity not only of single UVFs but especially that of complete sunscreen products to design more eco-friendly formulations in the future.

Bioremediation of the synthetic musk compounds Galaxolide and Tonalide by white rot fungal strain-assisted phytoremediation in biosolid-amended soil

The study was aimed to conduct the bioremediation of synthetic musks by four species of white rot fungi combined with phytoremediation (Zea mays) in biosolid-amended soils where only Galaxolide (HHCB) and Tonalide (AHTN) were found as other musks were below the detection limit (0.5-2 μg/kg dw). The HHCB and AHTN concentration in natural attenuation treated soil was decreased by not more than 9%. In solely mycoremediation, Pleurotus ostreatus was found to be the most efficient fungal strain, with the higher (P < 0.05) HHCB and AHTN removal (51.3% and 46.4%). Phytoremediation-only of biosolid-amended soil was also able to remove HHCB and AHTN from soil significantly (P < 0.05) in comparison to the control treatment without plants which resulted in the final concentration for both compounds of 56.2 and 15.3 μg/kg dw, respectively. Using white rot fungus-assisted phytoremediation, only P. ostreatus decreased the HHCB content in soil significantly (P < 0.05) by 44.7%, when compared to the initial concentration. While using Phanerochaete chrysosporium, the AHTN concentration was decreased by 34.5%, which was a significantly lower concentration at the end of experiment compared to the initial value. Via fungus-assisted phytoremediation, the enzymatic activity and fungal biomass were increased, probably due to the presence of roots in association with the soil microbiome, in the process increasing the degradation of fragrances accordingly. This could lead to a higher (P < 0.05) AHTN removal in P. chrysosporium assisted phytoremediation. Estimated HHCB and AHTN bioaccumulation factors in maize were lower than 1, therefore no environmental risk would be posed.

Environmental impacts of the ultraviolet filter oxybenzone

Organic UV filters are emerging contaminants with increasing evidence of their negative impact on environmental health and water quality. One of the most common and environmentally relevant organic UV filters is oxybenzone (OBZ). While much of the initial focus has been on investigating the interaction of OBZ with coral reefs, there have been several recent studies that indicate that organic UV filters are affecting other environmental endpoints, including marine animals, algae, and plants. OBZ has been found to bioaccumulate in marine animals such as fish and mussels and then potentially acting as an endocrine disruptor. In plants, exposure to OBZ has been associated with decreased photosynthesis, inhibited seed germination, and impaired plant growth. In this review, we summarize the current state of knowledge regarding the environmental impacts of OBZ and suggest potential future directions.

Occurrence and Gas-Particle Partitioning of Organic UV-Filters in Urban Air

A retrospective analysis of a comprehensive series of high-volume air samples (n = 70) collected during 2010-2011 in Toronto (Canada) was performed. Seven UV compounds were analyzed by gas chromatography-tandem mass spectrometry (GC-MS/MS) with sum of concentrations (gas + particle phase) ranging from 80 to 2030 pg/m³. Homosalate (HMS) was the most prevalent organic UV-filter in air (47% of the total concentration), followed by 2-ethylhexyl salicylate (EHS, ∼29%), E- and Z-2-ethylhexyl 4-methoxycinnamate (EHMC, ∼17%). Ambient air (gas + particle phase) concentrations of organic UV-filters showed a strong seasonality, with peak levels during the summer. An analysis of Clausius-Clapeyron slopes indicated that much of the ambient burden of organic UV-filters are explained by volatilization from terrestrial and aquatic surfaces and supplemented with human activities and use of lotions and sunscreens, containing organic UV-filters, in addition to its use in plastics, textiles, paints, and pesticides. The results showed that organic UV-filters exist mainly in the gas phase with some exceptions, for instance, octocrylene (OCR), which was associated with both gas and particle phases, and avobenzone (AVB), which was predominantly in the particle phase. Lastly, this study revealed the need for basic physical chemical property data for organic UV-filters, including information on transformation rates and products, for better evaluating their environmental fate and effects.

Investigations on the uptake and transformation of sunscreen ingredients in duckweed (Lemna gibba) and Cyperus alternifolius using high-performance liquid chromatography drift-tube ion-mobility quadrupole time-of-flight mass spectrometry

The uptake, translocation and transformation of three UV-blockers commonly employed in sunscreens, namely avobenzone, octocrylene and octisalate from water by Lemna gibba and Cyperus alternifolius was investigated. Reversed phase high performance liquid chromatography coupled to drift-tube ion-mobility quadrupole time-of-flight mass spectrometry was used for analyzing the extracts from the selected plants after incubation with the UV-blockers for one week. For avobenzone several transformation products resulting from hydroxylation, demethylation and oxidation of the parent molecule could be identified by measuring accurate mass, performing MS/MS experiments and by determining their drift-tube collision cross sections employing nitrogen as drift gas. In addition, the plants were subjected to two commercially available sunscreens, providing similar results to those obtained for the standard solutions of the UV-blockers. Finally, a kinetic study on the uptake and transformation of avobenzone, octocrylene and octisalate was conducted over a period of 216 h, revealing that the UV-filters were mostly present in their parent form and only to a smaller part converted into transformation products.

Evaluation of the airborne pollution by emerging contaminants using bitter orange (Citrus aurantium) tree leaves as biosamplers

In this work, an analytical method has been applied to biomonitor airborne emerging pollutants in urban areas using bitter orange (Citrus aurantium) tree leaves, which is an evergreen species widely extended in the Mediterranean region, as biosampler. Leaves, from trees located in 20 different locations from Seville City (South of Spain) were sampled during one year period. Sampling sites were located in six highly populated areas, in seven lowly populated areas, in six urban parks and in one industrial area. Fifteen of the target compounds were detected in the analysed samples. The highest concentrations corresponded to plasticizers (up to 852ng/g dry matter (dm)) and surfactants (up to 752ng/gdm), especially di(2-ethylhexyl)phthalate and nonylphenol. Spatial distribution allowed assessing the influence of populated areas in the concentration of some of the studied compounds, such as plasticizers and perfluorinated compounds, and the influence of industrial areas, in the concentration of surfactants. No clear influence of the climatic conditions (temperature, solar radiation and rainfall) on the concentrations of studied compounds was observed. This fact could be due to the presence of diffuse sources of these compounds. In the case of the brominated flame retardant, the measured concentrations could be related with two fire episodes in the vicinity, but until now it has not been possible to rigorously demonstrate a causal relationship. This fact could reveal the suitability and valuable use of Citrus aurantium tree leaves for biomonitoring atmospheric pollutants, especially from unexpected emissions in atmospheric pollution episodes.

Emerging pollutants in the urban water cycle in Latin America: A review of the current literature

Emerging pollutants (EP) are increasingly studied and characterized worldwide to improve the understanding of their environmental and toxicological impacts and their occurrence and behaviors in different environmental systems. Latin America has been subject to both environmental and toxicological impacts due to EP. To better understand these impacts, studies concerning pollutants have increased for the last ten years. The current study presents a critical review on the occurrence of different emerging pollutants in various components of the urban water cycle (UWC) in Latin America. The review is based on studies performed in 11 different countries between 1999 and 2018. The countries where the higher number of investigations were conducted are Brazil (53%) and Mexico (15%). The EP most often studied within the literature are pharmaceuticals, followed by personal care products. The most common EP reported were 17β-estradiol, bisphenol A and estrone; The UWC component with the greatest number of measurements in the reported studies were effluents from wastewater treatment plants.

Development and optimization of a QuEChERS-GC-MS/MS methodology to analyse ultraviolet-filters and synthetic musks in sewage sludge

A Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) methodology followed by gas chromatography-triple quadrupole mass spectrometry (GC-MS/MS) analysis was developed to extract synthetic musk compounds (SMCs) (6 polycyclic, 2 macrocyclic and 5 nitro musks) and ultraviolet-filters (UVFs) (6 compounds) from sludge. This methodology fills a gap in the literature, since the proposed technique does not require specific equipment, nor large amounts of solvents, sorbents and time to extract SMCs and UVFs from sludge. To optimize this new methodology, a design of experiments (DoE) approach was used, applying first a screening design (SD) and then a central composite design (CCD). The best conditions achieved to extract these 19 compounds simultaneously were: 500 mg freeze dried sludge, 2.5 min of vortex and 15 min ultrasound and the use of a QuEChERS for the dispersive solid-phase extraction (d-SPE) containing 500 mg MgSO₄, 410 mg C18 and 315 mg PSA. Then, this methodology was successfully validated. Recoveries of the target compounds ranged from 75% (cashmeran, DPMI) to 122% (2‑ethylhexyl 4‑methoxycinnamate, EHMC), with good repeatability (relative standard deviation < 10%). The instrumental detection limits (IDLs) and quantification (IQLs) varied from 0.001 pg (musk moskene, MM) to 7.5 pg (musk xylene, MX) and from 0.003 (MM) to 25 pg (MX), respectively. The method detection and quantification limits (MDLs and MQLs) ranged between 0.5 (DPMI) and 1394 (exaltolide, EXA) ng/g dw and 2 and 4648 ng/g-dw, respectively. Both SMCs and UVFs were detected in all sludge samples analysed. Higher concentrations were found for octocrylene (OC: maximum value of 115,486 ng/g-dw) followed by galaxolide (HHCB: 81,771 ng/g-dw). Only the nitro musks ambrette, xylene, moskene and tibetene and macrocyclic musk ethylene brassylate (EB) were not detected in any sample.

Removal of tridecane dicarboxylic acid in water by nanoscale Fe0/Cu0 bimetallic composites

In this study, nanoscale zerovalent Fe⁰/Cu⁰ bimetallic composites were synthesized by liquid-phase reduction of Fe(II)/Cu(II) and applied for decomposition of tridecane dicarboxylic acid (DC13). The removal performance of Fe⁰/Cu⁰ bimetallic composites for DC13 in terms of Fe/Cu ratios, addition amount, reaction time and initial pH were studied. The as-prepared nanoscale composites were characterized by a transmission electron micrographs (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), BET surface area, fourier transform infrared spectroscopy (FT-IR) and inductively coupled plasma-atomic emission spectrometry (ICP). Finally, the degradation mechanisms of DC13 utilizing the Fe⁰/Cu⁰ nanocomposites were investigated by using mass spectrumetry (MS). The results indicated that the Fe⁰/Cu⁰ bimetallic composites exerted a remarkable removal capacity for DC13 through the multiple reactions, e.g., coagulation, adsorption and •OH reduction in the Fe⁰/Cu⁰ system. XPS indicated that the Fe⁰/Cu⁰ reduction reaction of hydroxyl radicals (•OH) system played a significant role in degradation of DC13 and the LC-MS result suggested that DC13 was degraded into inorganic small molecules by •OH radicals generated from the corrosion of Fe⁰. The experimental results indicated that the nanoscale Fe⁰/Cu⁰ could be used as a potential material to remove DC13 because of its remarkable degradability.

Synthetic Musks: A Class of Commercial Fragrance Additives in Personal Care Products (PCPs) Causing Concern as Emerging Contaminants

Synthetic musks (SMs) are promising fragrance additives used in personal care products (PCPs). The widespread presence of SMs in environmental media remains a serious risk because of their harmful effects. Recently, the environmental hazards of SMs have been widely reported in various environmental samples including those from coastal and marine regions. This paper provides a systematic review of SMs, including their classification, synthetic routes, analysis and occurrence in environmental samples, fate and toxicity in the environment, as well as the associated risk assessment and pollution control. Research gaps and future opportunities were also identified with the hope of raising interest in this topic.

Multi-component determination of atmospheric semi-volatile organic compounds in soils and vegetation from Tarragona County, Catalonia, Spain

Tarragona County (Spain) is home to the most important chemical/petrochemical industrial complex in Southern Europe, which raises concerns about the presence and effects of the numerous environmental contaminants. In order to assess the levels and patterns of five classes of semi-volatile organic compounds (SVOCs) - polycyclic aromatic hydrocarbons (PAHs), synthetic musks (SMs), polychlorinated biphenyls (PCBs), brominated flame retardants (BFRs) and one organochlorine pesticide, hexachlorobenzene (HCB), 27 samples of soil and vegetation (Piptatherum L.) from different areas (petrochemical, chemical, urban/residential, and background) of Tarragona County were analysed. The results show that PAHs levels in soils ranged from 45.12 to 158.00ng/g and the urban areas presented the highest concentrations, mainly associated with the presence of a nearby highway and several roads with heavy traffic. PAHs levels in vegetation samples ranged from 42.13 to 80.08ng/g, where the greatest influence came from the urban and petrochemical areas. In the case of SMs, levels in soils and vegetation samples ranged from 5.42 to 10.04ng/g and from 4.08 to 17.94ng/g, respectively, and in both cases, background areas (at least 30km away from the main SVOCs emission sources) showed the highest levels, suggesting an influence of the personal care products derived from beach-related tourism in the coast. PCBs (from 6.62 to 14.07ng/g in soils; from 0.52 to 4.41ng/g in vegetation) prevailed in the chemical area in both matrices, probably associated with the presence of two sub-electrical stations located in the vicinities. In general terms, BFRs and HCB values recorded in soil and vegetation samples were quite similar between matrices and sampling areas.