Mining-related activities in the Alberta Oil Sands Region (AOSR) are known to emit polycyclic aromatic hydrocarbons (PAHs) and related compounds to ambient air. This is a concern due to the toxicity of PAHs, including their transformation products such as nitrated (NPAHs) and oxygenated (OPAHs) PAHs. This is the first study that provided a more extensive outlook into the sources, occurrence in air, and spatial and seasonal patterns of NPAHs and OPAHs in the AOSR by using passive air sampling. A sampling campaign from 2013 to 2016 revealed concentrations of NPAHs that were much lower than those of OPAHs. The highest concentrations of NPAHs were concentrated in the region associated with extensive mining activities, with ∑NPAH concentrations ranging from 20 to 250 pg/m³. Within the oil sands (OS) mineable area, NPAHs associated with primary release appear more commonly, while NPAHs produced via oxidative transformation are predominant outside of this area. The concentrations of ∑OPAH ranged from 400 to 2400 pg/m³, with the highest air concentrations in the region located south of the main OS activity zone, with peak concentrations attributed to a 2016 forest fire event. Uptake of PAHs from ambient air and their subsequent conversion to generate OPAHs is believed to play an important role in wildfire emissions of OPAHs. The seasonal trend investigation was inconclusive, with NPAHs slightly higher during the winter, while OPAHs were slightly elevated during summer. A preliminary comparison of ambient concentrations of OPAHs and NPAHs in the AOSR to measurements in the Greater Toronto Area revealed a similar range of concentrations, but also a unique presence of certain NPAHs such as 4-nitrobiphenyl, 2-nitrodibenzothiophene, 2,8-dinitrodibenzothiophene and 6-nitrobenzo-(a)-pyrene. This indicates that AOSR might have its own NPAH profile – creating the need to better understand associated NPAH toxicity and propensity for long range transport.

While polychlorinated biphenyl (PCB)-related risks have been reported at the cellular, organ, and individual levels in some marine mammals, studies quantifying the PCB-associated population-level effects are limited. Here, we combined chemical analysis and individual-based model simulation to investigate the impact of PCBs on the Indo-Pacific humpback dolphin (sub)population from the Pearl River Estuary (PRE). An annual PCB accumulation rate of 0.29 ± 0.07 mg/kg lipid per year was estimated based on the measured age-specific male data as males continue to accumulate PCBs throughout their lifetime, without depurating contaminant loads. Using the Taiwan Strait dolphin population with low PCBs as a baseline, we compare our model simulations in PRE population to estimate relative population impacts of PCBs and other stressors. When using the current vital rates of the PRE dolphins which have been affected by PCBs and other stressors (e.g., underwater noise, prey limitation, etc.), our simulations revealed a substantial decline (8.1%) in the annual population growth rate (λ) of PRE metapopulation compared to baseline over the next 100 years. At the estimated PCB accumulation rate, the PCB-mediated effects on calf survival and immunity would cause a slight decline (0.9%) in λ relative to baseline. Our findings suggest a relatively limited impact of PCBs on the long-term survival of PRE dolphins among all stressors. However, it should be noted that even under model simulations where dietary PCBs were eliminated, humpback dolphins would still need a long time to reduce their PCB burdens to a relatively “safe” level through biological cycling. Considering that the baseline vital rates might also have been affected by PCBs and other stressors, our results are considered relative rather than absolute. This study provides a starting point for quantifying population-level consequences of contaminant exposure on humpback dolphins, although more efforts are needed to perfect this type of analysis.

We assessed the performance of taxonomic and several functional trait-based approaches in the assessment of spatial and temporal patterns of dusky flounder (Syacium papillosum) parasite assemblages along the Yucatan shelf to determine their potential as bioindicators of marine chemical pollution. Fish specimens were collected throughout three research cruises that took place in 2015, 2016 and 2018. In addition to the traditional taxonomic approach, four trait-based approaches were performed including community-weighted means (CWM), functional trait niche (FTN), functional groups (FGs), and Rao's functional diversity (FD). Significant spatial and temporal variations in parasite communities were detected using the taxonomic approach. In general, these variations were also reflected in the four trait-based approaches performed, indicating that changes in taxa composition and abundance also resulted in functional composition shifts. Resemblance matrices of both taxonomic and functional trait approaches were significantly correlated. Variations in taxonomic and trait-based composition using the four approaches were significantly correlated with depth, and at least one chemical pollutant variable. Feeding mode, transmission, life stage and attachment structure displayed spatial variability and significant correlations with predictor variables, which indicates that this set of attributes functions as a good surrogate for assessing variations in the functional composition of flatfish parasite communities in relation to pollution. FTN and CWM were the approaches that best detected spatio-temporal variation. CWM and FD were best suited for detecting pollution gradients. These results reveal the feasibility of using trait-based approaches to assess marine parasite communities as bioindicators of chemical pollution. Functional traits of marine metazoan parasites are as good indicators of the effect of oil pollution as taxonomic diversity. This may be a time-saving and cost-effective approach to performing environmental assessments.

Air pollution constitutes the greatest environmental threat to human health in the European Union. In Poland, the emission of particulate matter and harmful gases originating from local coal based boiler plants and the combustion of fuels in residential heating appliances is a considerable source of air pollution. The combustion of fuel in home furnaces is inefficient due to the use of cheap fuels of low heating parameters and the frequent addition of waste. For the purpose of the research, deciduous tree wood pellets were selected as the basic fuel with the admixture of plastic waste, rubber, waste paper, wood residues, diapers, textile waste, multi-material packaging, construction waste, biomass and alternative fuel (RDF). Examining ash samples to confirm the practices of combusting or co-combusting waste materials in heating appliances is considered to be one of the most reliable detection methods; however, the results of direct research require further data processing. The application of hierarchical clustering analysis to the obtained results arranged into a matrix enabled in a simple way to demonstrate the similarities between the examined samples of fuel and the samples of fuel mixed with waste materials in the parameters space as well as to analyze the similarities among the measured parameters (the content of particular elements in ash) in the space of the examined samples. The application of chemometric methods for the purpose of identifying the combusted fuels, and, in particular the co-combusted waste complements the currently used monitoring tools which control the use of low quality fuels or the combustion of waste of different origin.

In order to assess risks to the natural environment from microplastics, it is necessary to have reliable information on all potential inputs and discharges. This relies on stringent quality control measures to ensure accurate reporting. Here we focus on wastewater treatment works (WwTWs) and the complex sample matrices these provide. Composite samples of both influent and effluent were collected over a 24 h period on two separate occasions from eight different WwTWs across the UK. Sludge samples were taken on five occasions from five WwTWs. The WwTW treatments included activated sludge, trickling filter and biological aerated flooded filter with or without tertiary treatment. Using micro-FTIR analysis, microplastics ≥25 μm were identified and quantified. Procedural blanks were used to derive limits of detection (LOD) and limits of quantification (LOQ). Where values were above the LOQ, microplastics in the influent ranged from 955 to 17,214 microplastic particles/L and in the effluent from 2 to 54 microplastic particles/L, giving an average removal rate of 99.8%. Microplastics could be quantified in sludge at concentrations of 301–10,380 microplastics/g dry weight, this analytical method therefore revealing higher concentrations than reported in previous studies. The most common polymers present overall were polyethylene (PE), polypropylene (PP) and polyethylene terephthalate (PET). We also report on critical considerations for blank corrections and quality control measures to ensure reliable microplastic analysis across different sample types.

Amongst other threats, the world’s oceans are faced with man-made pollution, including an increasing number of microparticulate pollutants. Sponges, aquatic filter-feeding animals, are able to incorporate fine foreign particles, and thus may be a potential bioindicator for microparticulate pollutants. To address this question, 15 coral reef demosponges sampled around Bangka Island (North Sulawesi, Indonesia) were analyzed for the nature of their foreign particle content using traditional histological methods, advanced light microscopy, and Raman spectroscopy. Sampled sponges accumulated and embedded the very fine sediment fraction (<200 μm), absent in the surrounding sand, in the ectosome (outer epithelia) and spongin fibers (skeletal elements), which was confirmed by two-photon microscopy. A total of 34 different particle types were identified, of which degraded man-made products, i.e., polystyrene, particulate cotton, titanium dioxide and blue-pigmented particles, were incorporated by eight specimens at concentrations between 91 and 612 particle/g dry sponge tissue. As sponges can weigh several hundreds of grams, we conservatively extrapolate that sponges can incorporate on average 10,000 microparticulate pollutants in their tissue. The uptake of particles, however, appears independent of the material, which suggests that the fluctuation in material ratios is due to the spatial variation of surrounding microparticles. Therefore, particle-bearing sponges have a strong potential to biomonitor microparticulate pollutants, such as microplastics and other degraded industrial products.

Public concern over the health implications of antimicrobials employed in aquaculture has resulted in adoption of strict regulations for their use. This study employed a high-throughput protocol covering 86 compounds in six pharmaceutical groups to screen feed and sediments from 20 tilapia ponds randomly in 18 farms of an aquacultural unit in southern China, one of important tilapia fillet suppliers in the world. Seventeen samples of commercial feeds from manufacturer-sealed bags in the farms were tetracyclines-free but not antibiotic-free. All the sealed-bag feeds contained quinolones and two feeds had sulfonamides (up to 140 μg kg⁻¹). Meanwhile, seven leftover-feeds in opened bags contained added antimicrobials: tetracyclines (570–2790 μg kg⁻¹) in all and florfenicol (20–294 μg kg⁻¹) in four. All the feeds regardless sealed or not had large amounts (221–2642 μg kg⁻¹) of salicylic acid (possible antimicrobial substitute) and caffeine, and one sealed-bag feed even was quantified with medroxyprogesterone. Surface sediments (0–10 cm) from the ponds were detected with 36 compounds and sublayer sediments (10–20) with 8 compounds. Large amounts of salicylic acid were present in both surface and sublayer sediments accounting up to 10% of total pharmaceutical residues. Surface sediments were dominated by antibiotics (5.2–172 μg kg⁻¹), mainly sulfonamides and quinolones, contributing 68% of the total quantitative compound mass. Sublayer sediments were also enriched in quinolones (up to 260 μg kg⁻¹). Surprisingly, all sediments contained progesterone (up to 8.0 μg kg⁻¹) in coincidence to the feed with medroxyprogesterone, perhaps arising from endocrine abuses or cross-contamination. Although high levels of other pharmacologic residues (caffeine) in sediment posed greater than medium ecological risks, antibiotic residues contributed only 2–35% to the risk. These findings suggest that antibiotic-free feed may be insufficient to control antibiotic abuse in aquaculture and that additional regulatory actions may be necessary, such as veterinary prescription as human antibiotic uses.

Phthalates are plasticizers in various products and regarded as endocrine disruptors due to their anti-androgen effects. Environmental occurrence and toxicities of parent phthalates have been widely reported, while the current state of knowledge on their metabolites is rarely summarized. Based on the available literature, the present review mainly aims to 1) characterize the potential metabolites of phthalates (mPAEs) using the pharmacokinetics evidences acquired via animal or human models; 2) examine the molecular and cellular mechanism involved in toxicity for mPAEs; 3) investigate the exposure levels of mPAEs in different human specimens (e.g., urine, blood, seminal fluid, breast milk, amniotic fluid and others) across the globe; 4) discuss the models and related parameters for phthalate exposure assessment. We suggest there is subtle difference in toxic mechanisms for mPAEs compared to their parent phthalates due to their alternative chemical structures. Human monitoring studies performed in Asia, America and Europe have provided the population exposure baseline levels for typical phthalates in different regions. Urine is the preferred matrix than other specimens for phthalate exposure study. Among ten urinary mPAEs, the largest proportions of di-(2-ethylhexyl) phthalate (DEHP) metabolites (40%), monoethyl phthalate (mEP) (43%) and DEHP metabolites/mEP (both 29%) were observed in Asia, America and Europe respectively, and mono-5-carboxy-2-ethypentyl phthalate was the most abundant compounds among DEHP metabolites. Daily intakes of phthalates can be accurately calculated via urinary mPAEs if the proper exposure parameters were determined. Further work should focus on combining epidemiological and biological evidences to establish links between phthalates exposure and biological phenotypes. More accurate molar fractions (FUE) of the urinary excreted monoester related to the ingested diesters should be collected in epidemiological or pharmacokinetic studies for different population.

The presence of microplastics in the various food web raised concerns on human health, but little is known about the target cells and mechanism of toxicity of microplastics. In this study, we evaluated the toxicity of microplastics using relevant cell lines to the oral route of exposure. Approximately 100 μm-sized fragment-type polypropylene (PP) and polystyrene (PS) particles were prepared by sieving after pulverization and further applied the accelerated weathering using ultraviolet and heat. Thus, the panel of microplastics includes fresh PP (f-PP), fresh PS (f-PS), weathered PP (w-PP), and weathered PS (w-PS). The spherical PS with a similar size was used as a reference particle. Treatment of all types of PP and PS did not show any toxic effects to the Caco-2 cells and HepG2 cells. However, the treatment of microplastics to THP-1 macrophages showed significant toxicity in the order of f-PS > f-PP > w-PS > w-PP. The weathering process significantly reduced the reactive oxygen species (ROS) generation potential of both microplastics because the weathered microplastics have an increased affinity to bind serum protein which acts as a ROS scavenger. The intrinsic ROS generation potential of microplastics showed a good correlation with the toxicity endpoints including cytotoxicity and pro-inflammatory cytokines in THP-1 macrophages. In conclusion, the results of this study suggest that the target cell type of microplastics via oral administration can be macrophages and the pathogenic factor to THP-1 macrophages is the intrinsic ROS generation potential of microplastics. Nevertheless, the toxic effect of microplastics tested in this study was much less than that of nano-sized particles.