Microplastic debris is ubiquitous and yet sampling, classifying and enumerating this prolific pollutant in marine waters has proven challenging. Typically, waterborne microplastic sampling is undertaken using nets with a 333 μm mesh, which cannot account for smaller debris. In this study, we provide an estimate of the extent to which microplastic concentrations are underestimated with traditional sampling. Our efforts focus on coastal waters, where microplastics are predicted to have the greatest influence on marine life, on both sides of the North Atlantic Ocean. Microplastic debris was collected via surface trawls using 100, 333 and 500 μm nets. Our findings show that sampling using nets with a 100 μm mesh resulted in the collection of 2.5-fold and 10-fold greater microplastic concentrations compared with using 333 and 500 μm meshes respectively (P < 0.01). Based on the relationship between microplastic concentrations identified and extrapolation of our data using a power law, we estimate that microplastic concentrations could exceed 3700 microplastics m⁻³ if a net with a 1 μm mesh size is used. We further identified that use of finer nets resulted in the collection of significantly thinner and shorter microplastic fibres (P < 0.05). These results elucidate that estimates of marine microplastic concentrations could currently be underestimated.

In the marine environment, microplastic contamination and acidification may occur simultaneously, this study evaluated the effects of ocean acidification and microplastics on oxidative stress responses and digestive enzymes in mussels. The thick shell mussels Mytilus coruscus were exposed to four concentrations of polystyrene microspheres (diameter 2 μm, 0, 10, 10⁴ and 10⁶ particles/L) under two pH levels (7.7 and 8.1) for 14 days followed by a 7-day recovery acclimation. Throughout the experiment, we found that microplastics and ocean acidification exerted little oxidative stress to the digestive gland. Only catalase (CAT) and glutathione (GSH) showed a significant increase along with increased microplastics during the experiment, but recovered to the control levels once these stressors were removed. No significant effects of pH and microplastics on glutathione peroxidase (GPx) and superoxide dismutase (SOD) were observed. The responses of digestive enzymes to both stressors were more pronounced than antioxidant enzymes. During the experiment, pepsin (PES), trypsin (TRS), alpha-amylase (AMS) and lipase (LPS) were significantly inhibited under microplastics exposure and this inhibition was aggravated by acidification conditions. Only PES and AMS tended to recover during the recovery period. Lysozyme (LZM) increased significantly under microplastic exposure conditions, but acidification did not exacerbate this effect. Therefore, combined stress of microplastics and ocean acidification slightly impacts oxidative responses but significantly inhibits digestive enzymes in mussels.

The proportion of asthma patients with mild to moderate exacerbations is far greater than the number who experience episodes that are severe enough to require emergency room visits or hospital admission. However the routinely collected data from hospitals is absent in the past.To evaluate associations between short-term exposures to air pollutants and hospital outpatient visits for asthma in China.We obtained data for 143,057 asthma outpatient visits from the largest hospitals in 17 Chinese cities, between Jan 01 2013 and Dec 31 2015. We used daily concentrations of air pollutants measured by the China National Environmental Monitoring Centre. We used a time-stratified case-crossover design, and fitted conditional logistic regression models to determine the associations.Particulate matter ≤10μm in diameter (PM10) and nitrogen dioxide (NO2) were associated with increased risks of hospital outpatient visits for asthma on the same day, while the effects were delayed for particulate matter ≤2.5μm in diameter (PM2.5) and sulphur dioxide (SO2). For the cumulative effect model at lag05 days, 10 μg/m3 increase in air pollutants concentrations were correlated with hospital outpatient visits for asthma with odds ratios (ORs) and 95% confidence intervals 1.004 (1.000-1.008) for PM2.5, 1.005 (1.002-1.008) for PM10, 1.030 (1.021-1.040) for NO2, and 1.015 (1.008-1.021) for SO2. Almost one in nine (10.9%; 7.7, 13.9%) hospital outpatient visits for asthma were attributable to NO2.Short-term exposures to PM2.5, PM10, NO2 and SO2 were associated with hospital outpatient visits for asthma in China.

Cryptosporidium and Giardia are important parasites due to their zoonotic potential and impact on human health, often causing waterborne outbreaks of disease. Detection of (oo)cysts in water matrices is challenging and few countries have legislated water monitoring for their presence. The aim of this study was to investigate the presence and origin of these parasites in different water sources in Northern Greece and identify interactions between biotic/abiotic factors in order to develop risk-assessment models. During a 2-year period, using a longitudinal, repeated sampling approach, 12 locations in 4 rivers, irrigation canals, and a water production company, were monitored for Cryptosporidium and Giardia, using standard methods. Furthermore, 254 faecal samples from animals were collected from 15 cattle and 12 sheep farms located near the water sampling points and screened for both parasites, in order to estimate their potential contribution to water contamination. River water samples were frequently contaminated with Cryptosporidium (47.1%) and Giardia (66.2%), with higher contamination rates during winter and spring. During a 5-month period, (oo)cysts were detected in drinking-water (<1/litre). Animals on all farms were infected by both parasites, with 16.7% of calves and 17.2% of lambs excreting Cryptosporidium oocysts and 41.3% of calves and 43.1% of lambs excreting Giardia cysts. The most prevalent species identified in both water and animal samples were C. parvum and G. duodenalis assemblage AII. The presence of G. duodenalis assemblage AII in drinking water and C. parvum IIaA15G2R1 in surface water highlights the potential risk of waterborne infection. No correlation was found between (oo)cyst counts and faecal-indicator bacteria. Machine-learning models that can predict contamination intensity with Cryptosporidium (75% accuracy) and Giardia (69% accuracy), combining biological, physicochemical and meteorological factors, were developed. Although these prediction accuracies may be insufficient for public health purposes, they could be useful for augmenting and informing risk-based sampling plans.

Road dust samples from industrial, urban, and tourist areas of the international tourist city of Guilin, China, were collected to study the concentration, spatial distribution, pollution level, and health risk of potentially toxic elements (PTEs) using an array-based risk assessment model from the United States Environmental Protection Agency. The geoaccumulation index (Igₑₒ), ecological risk index, and spatial interpolation were used to investigate the road dust pollution level. The results indicated that apart from Ni and Al, the concentration of all the heavy metals (Pb, Zn, Ni, Cu, Cr, Cd, Fe, Mn, and As) were markedly higher than the corresponding background values in the three functional areas. Based on the Igₑₒ, the study area had an uncontaminated to moderate pollution level, and the industrial area was slightly more polluted and posed a greater ecological risk than the urban and tourist areas. Comparatively, Pb, Zn, and Cu exhibited higher pollution levels in the three functional sites. Hotspots of PTEs were more concentrated in urban and industrial areas than in tourist areas. Furthermore, the health risk model revealed significant non-carcinogenic risks to children from As in urban, industrial, and tourist areas as the hazard quotients (1.64, 2.04, and 1.42, respectively) exceeded the threshold standard of 1.00. The carcinogenic risk via ingestion (RIᵢₙg) illustrated significant risks to children from Cr, As, and Ni because the RIᵢₙg values were considerably higher than the threshold standard (1.00E-6 to 1.00E-4) in the three functional areas. However, no cancer risk was observed from the dermal and inhalation pathways.

Sunscreen chemicals, such as benzophenones (BPs), are common environmental contaminants that are posing a growing health concern due to their increasing presence in water, fish, and human systems. Benzoresorcinol (BP1), oxybenzone (BP3), and dioxybenzone (BP8) are the most commonly used BPs for their ability to protect from sunburn by absorbing a broad spectrum of ultraviolet radiation. In this study, zebrafish larvae were used as an in vivo model to investigate the potential risks and molecular mechanisms of the toxic effects of BPs. The effects of these BPs on the gene expression in the aryl hydrocarbon receptor pathway, estrogen receptor pathway, and sex differentiation were detected using quantitative real-time PCR. All BPs were found to function as agonists of the estrogen receptors α and β1, indicating that these BPs likely undergo similar molecular metabolism in vivo, whereby they can activate cytochrome P450 genes and promote the expression of CYP19A and DMRT1. Furthermore, the gene expression profile of larvae after BP3 exposure was evaluated using a whole transcriptome sequencing approach. BP3 affected estradiol biosynthesis and sex differentiation. It also regulated gonadotropin-releasing hormone, thus interfering with the endocrine system. As a xenobiotic toxicant, BP3 upregulated the expression of cytochrome P450 genes (CYP1A and CYP3A65) and glutathione metabolism-related genes (GSTA, GSTM, and GSTP). It also interfered with the nervous system by regulating the calcium signaling pathway. These findings will be useful for understanding the toxicity mechanisms and metabolism of BPs in aquatic organisms and promote the regulation of these chemicals in the environment.

The complexation with extracellular polymeric substances (EPS) greatly reduces the toxicity of heavy metals towards organisms in the environment. However, the molecular mechanism of EPS−metal complexation remains unclear owing to the limitation of precise analysis for key fractions and functionalities in EPS that associate with metals. Herein, we explored the EPS−Cd (II) complexation by fluorescence excitation emission matrix coupled with parallel factor (EEM−PARAFAC), two-dimensional Fourier transform infrared correlation spectroscopy (2D-FTIR−COS) and X-ray photoelectron spectroscopy (XPS), attempting to explain the mechanisms of EPS in alleviating Cd (II) toxicity toward a green alga Chlorella vulgaris (C. vulgaris). When the algal EPS were removed, the cell internalizations of Cd (II), growth inhibition rate and chlorophyll autofluorescence increased, but the surface adsorption and esterase activities decreased, indicating that the sorption of Cd (II) by EPS was crucial in alleviating the algal toxicity. Moreover, the complexation with proteins in EPS controlled the sorption of Cd (II) to algal EPS, resulting in the chemical static quenching of the proteins fluorescence by 47.69 ± 2.37%. Additionally, the complexing capability of the main functionalities, COO⁻ and C–OH in proteins with Cd (II) was stronger than that of C–O(H) and C–O–C in polysaccharides or C–OH in the humus-related substances. Oxygen atom in protein carboxyl C–O might be the key site of EPS−Cd (II) complexation, supported by the modified Ryan−Weber complexation model and the obvious shift of oxygen valence-electron signal. These findings provide deep insights into understanding the interaction of EPS with heavy metals in aquatic environment.

Modification of nighttime light levels by artificial illumination (artificial light at night; ALAN) is a rapidly increasing form of human disturbance that affects natural environments worldwide. Light in natural environments influences a variety of physiological and ecological processes directly and indirectly and, as a result, the effects of light pollution on species, communities and ecosystems are emerging as significant. Small prey species may be particularly susceptible to ALAN as it makes them more conspicuous and thus more vulnerable to predation by visually oriented predators. Understanding the effects of disturbance like ALAN is especially important for threatened or endangered species as impacts have the potential to impede recovery, but due to low population numbers inherent to at-risk species, disturbance is rarely studied. The endangered Stephens’ kangaroo rat (SKR), Dipodomys stephensi, is a nocturnal rodent threatened by habitat destruction from urban expansion. The degree to which ALAN impacts their recovery is unknown. In this study, we examined the effects of ALAN on SKR foraging decisions across a gradient of light intensity for two types of ALAN, flood and bug lights (756 vs 300 lumen, respectfully) during full and new moon conditions. We found that ALAN decreased probability of resource patch depletion compared to controls. Moreover, lunar illumination, distance from the light source and light type interacted to alter SKR foraging. Under the new moon, SKR were consistently more likely to deplete patches under control conditions, but there was an increasing probability of patch depletion with distance from the source of artificial light. The full moon dampened SKR foraging activity and the effect of artificial lights. Our study underscores that ALAN reduces habitat suitability, and raises the possibility that ALAN may impede the recovery of at-risk nocturnal rodents.

Microplastics pose threats to aquatic environments because they serve as hard-substrate for microbial community colonization and biofilm formation due to their long-life span and hydrophobic surface which can impact on aquatic ecosystems. However, the association between microplastics and other pollutants, particularly nutrients and metals in river sediments are largely unknown. In this study, microplastics abundance and hazard scores which are the risks arising from chemical compounds used for plastics manufacture, and the correlations between microplastics and the concentrations of total carbon (TC), total nitrogen (TN), total phosphorus (TP) and metals commonly present in the urban environment such as Al, As, Cr, Co, Cu, Fe, Mg, Mn, Ni, Cd, Se, Sr, Zn, Pb, in Brisbane River sediments were investigated. The study confirmed that the risk associated with microplastics is based on their monomer composition rather than the quantities present. Sediments having relatively higher abundance of microplastics with a relatively lower hazard score result in higher nutrient concentrations. The concentrations of metals in river sediments are more dependent on their original sources rather than the concentration of microplastics. Nevertheless, leachate from plastics should be considered in risk assessment in relation to the association between metals and plastics in aquatic environments.