Samples of microplastic (n = 924) from two beaches in south west England have been analysed by field-portable-x-ray fluorescence (FP-XRF) spectrometry, configured in a low-density mode and with a small-spot facility, for the heavy metals, Cd and Pb, and the halogen, Br. Primary plastics in the form of pre-production pellets were the principal type of microplastic (>70%) on both beaches, with secondary, irregularly-shaped fragments representing the remainder of samples. Cadmium and Pb were detected in 6.9% and 7.5% of all microplastics, respectively, with concentrations of either metal that exceeded 103 μg g−1 usually encountered in red and yellow pellets or fragments. Respective correlations of Cd and Pb with Se and Cr were attributed to the presence of the coloured, inorganic pigments, cadmium sulphoselenide and lead chromate. Bromine, detected in 10.4% of microplastics and up to concentrations of about 13,000 μg g−1, was mainly encountered in neutrally-coloured pellets. Its strong correlation with Sb, whose oxides are effective fire suppressant synergists, suggests the presence of a variety of brominated flame retardants arising from the recycling of plastics originally used in casings for heat-generating electrical equipment. The maximum bioaccessible concentrations of Cd and Pb, evaluated using a physiological extraction based on the chemical characteristics of the proventriculus-gizzard of the northern fulmar, were about 50 μg g−1 and 8 μg g−1, respectively. These concentrations exceed those estimated for the diet of local seabirds by factors of about 50 and 4, respectively.

The Midwest United States is an intensely agricultural region where pesticides in streams pose risks to aquatic biota, but temporal variability in pesticide concentrations makes characterization of their exposure to organisms challenging. To compensate for the effects of temporal variability, we deployed polar organic chemical integrative samplers (POCIS) in 100 small streams across the Midwest for about 5 weeks during summer 2013 and analyzed the extracts for 227 pesticide compounds. Analysis of water samples collected weekly for pesticides during POCIS deployment allowed for comparison of POCIS results with periodic water-sampling results. The median number of pesticides detected in POCIS extracts was 62, and 141 compounds were detected at least once, indicating a high level of pesticide contamination of streams in the region. Sixty-five of the 141 compounds detected were pesticide degradates. Mean water concentrations estimated using published POCIS sampling rates strongly correlated with means of weekly water samples collected concurrently, however, the POCIS-estimated concentrations generally were lower than the measured water concentrations. Summed herbicide concentrations (units of ng/POCIS) were greater at agricultural sites than at urban sites but summed concentrations of insecticides and fungicides were greater at urban sites. Consistent with these differences, summed concentrations of herbicides correlate to percent cultivated crops in the watersheds and summed concentrations of insecticides and fungicides correlate to percent urban land use. With the exception of malathion concentrations at nine sites, POCIS-estimated water concentrations of pesticides were lower than aquatic-life benchmarks. The POCIS provide an alternative approach to traditional water sampling for characterizing chronic exposure to pesticides in streams across the Midwest region.

Microplastic (MP) vector effects have been well described in the literature but surprisingly little is in known about the impact of MPs on the intestinal uptake of contaminants. The present study aimed to determine whether the intestinal fate of Ag was affected by the presence of polyethylene MP beads. Ag (added as ¹¹⁰ᵐAg) was introduced into the lumen of rainbow trout (Oncorhynchus mykiss) anterior/mid-intestine gut sac preparations as Ag only, Ag and MPs (co-exposure) and Ag-incubated MPs (where Ag was adsorbed to the MP). Results show that after 3 h exposure the distribution of accumulated Ag between the four intestinal compartments (mucus layer, mucosal epithelium, muscle layer and serosal saline) was not affected by either MP condition when compared to Ag alone (p > 0.05, One way ANOVA). Across all treatment groups mucus layer binding dominated (54.2–72.6%) whereas relatively little Ag was transported to the blood compartment (i.e. combined muscle layer and serosal saline compartments, 8.5–15.0%). Accompanying adsorption/desorption studies were performed in relevant media. Over 24 h, 60.6± 2.9% of the available Ag in artificial freshwater adhered to the surface of the PE MPs. In pH adjusted luminal fluids (pH 2.2, 4.1, 7.4 and 9.8) that span the range of conditions encountered within the rainbow trout digestive tract, there was almost complete dissociation at acidic pHs within 3 h (<2% remaining on MPs at both pH 2.2 and pH 4.1). Such pHs are typical of piscine stomach. Based on our finding we suggest that following the ingestion of MPs with adsorbed pollutants, desorption would occur prior to entering the site of uptake. The MPs themselves have no impact on the trans-epithelial transport of the contaminant, but the net result of the MP vector effect is to potentially introduce labile contaminant forms into the intestine.

Like many urban catchments, the River Thames in London is contaminated with plastics. This pollutant is recorded on the river banks, in the benthic environment and in the water column. The present study was conducted to assess the extent of microplastic ingestion in two River Thames fish species, the European flounder (Platichthys flesus) and European smelt (Osmerus eperlanus). Samples were collected from two sites in Kent, England; Erith and Isle of Grain/Sheppey, near Sheerness, with the latter being more estuarine. The results revealed that up to 75% of sampled European flounder had plastic fibres in the gut compared with only 20% of smelt. This difference may be related to their diverse feeding behaviours: European flounder are benthic feeders whilst European smelt are pelagic predators. The fibres were predominantly red or black polyamides and other fibres included acrylic, nylon, polyethylene and polyethylene terephthalate and there was no difference in occurrence between the sites sampled.

Correct characterization of metal speciation and reactivity is a prerequisite for the risk assessment and remedial activity management of contaminated soil. To better understand the intrinsic reactivity of Pb and Zn, nine heavily and poorly contaminated soils were investigated using the combined approaches of chemical extractions, multi-element stable isotopic dilution (ID) method, and multi-surface modelling. The ID results show that 0.1–38% of total Pb and 3–45% of total Zn in the studied soils are isotopically exchangeable after a 3-day equilibration. The intercomparison between experimental and modelling results evidences that single extraction with 0.43 M HNO3 solubilizes part of non-isotopically exchangeable fraction of Pb and Zn in the studied soils, and cannot be used as a surrogate for ID to assess labile Pb and Zn pools in soil. Both selective sequential extraction (SSE) and modelling reveal that Mn oxides are the predominant sorption surface for Pb in the studied soils; while Zn is predicted to be mainly associated with soil organic matter in the soil with low pH and Fe/Mn oxides in the soils with high pH. Multi-surface modelling can provide a reasonable prediction of Pb and Zn adsorption onto different soil constituents for the most of the studied soils. The modelling could be a promising tool to decipher the underlying mechanism that controls metal reactivity in soil, but the submodel for Mn oxides should be incorporated and the model parameters, especially for the 2-pK diffuse layer model for Mn oxides, should be updated in the further studies.

To examine the impacts of urbanization and industrialization on the coastal environment, and assess the effectiveness of control measures on the contamination by chlorinated paraffins (CPs) in East Asia, surface and core sediments were sampled from the urbanized coastal zones in China and Japan (i.e., Pearl River Delta (PRD), Hong Kong waters and Tokyo Bay) and analyzed for short-chain (SCCPs) and medium-chain CPs (MCCPs). Much higher concentrations of CPs were found in the industrialized PRD than in adjacent Hong Kong waters. Significant correlation between CP concentration and population density in the coastal district of Hong Kong was observed (r² = 0.72 for SCCPs and 0.55 for MCCPs, p < 0.05), highlighting the effect of urbanization. By contrast, a relatively lower pollution level of CPs was detected in Tokyo Bay. More long-chain groups within SCCPs in the PRD than in Hong Kong waters and Tokyo Bay implied the effect of industrialization. Comparison of temporal trends between Hong Kong outer harbor with Tokyo Bay shows the striking difference in historical deposition of CPs under different regulatory situations in China and Japan. For the first time, the declining CP concentrations in Tokyo Bay, Japan, attest to the effectiveness of emissions controls.

Bacteriophages (phages) are the most abundant and diverse biological entities in our planet. They infect susceptible bacterial hosts into which they either multiply or persist. In the latter case, phages can confer new functions to their hosts as a result of gene transfer, thus contributing to their adaptation (short-term) and evolution (long-term). In this regard, the role of phages on the dissemination of antibiotic resistance genes (ARGs) among bacterial hosts in natural environments has not yet been clearly resolved. Here, we carry out a comprehensive analysis of thirty-three viromes from different habitats to investigate whether phages harbor ARGs. Our results demonstrate that while human-associated viromes do not or rarely carry ARGs, viromes from non-human sources (e.g. pig feces, raw sewage, and freshwater and marine environments) contain a large reservoir of ARGs, thus pointing out that phages could play a part on the spread of antibiotic resistance. Given this, the role of phages should not be underestimated and it should be considered when designing strategies to tackle the global crisis of antibiotic resistance.

Urban greenspaces provide ecosystem services like more natural ecosystems do. For instance, vegetation modifies soil properties, including pH and soil organic matter content, yet little is known about its effect on metals. We investigated whether the accumulation and mobility of heavy metals, nutrients and carbon is affected by plant functional types (evergreen or deciduous trees, lawns) in urban parks of varying ages in southern Finland. Plant types modified soil physico-chemical parameters differently, resulting in diverging accumulation and mobility of metals and other elements in park soils. However, the effects of plant functional type depended on park age: lawns in parks of ca. 50 y old had the highest contents of Cr, Cu, Fe, Mn, Ni, and Zn, and in these, and older parks (>100 y old), contents of most metals were lowest under evergreen trees. The mobility of metals and other elements was influenced by the amount of water leached through the soils, highlighting the importance of vegetation on hydrology. Soils under evergreen trees in young parks and lawns in intermediately-aged parks were most permeable to water, and thus had high loads of Ca, Cr, Cu, Fe, Ni, tot-P and tot-N. The loads/concentrations of elements in the leachates was not clearly reflected by their content/concentration in the soil, alluding to the storage capacity of these elements in urban park soils. Our results suggest that in urban systems with a high proportion of impermeable surfaces, park soil has the potential to store nutrients and metals and provide an important ecosystem service particularly in polluted cities.

The ability of Posidonia oceanica spheroids (egagropiles, EG) to incorporate plastics was investigated along the central Italy coast. Plastics were found in the 52.84% of the egagropiles collected (n = 685). The more represented size of plastics has range within 1–1.5 cm, comparable to the size of natural fibres. Comparing plastics occurring both in EG and in surrounding sand, Polyethylene, Polyester and Nylon were the most abundant polymers in EG, while PSE, PE, PP and PET were the most represented in sand. In particular PE and PP were significantly more represented in sand, while PE, Nylon, Polyester and microfibers (as pills) were more represented in EG. Within plastics found in EG, 26.9% were microfibers as small pills (<1 cm), mainly composed of polyamide, polyester, cotton and PET mixing. These microfibers might be produced by discharges from washing machines and currently represents an emerging pollutant with widespread distribution in marine and freshwater ecosystems.

Subarctic lakes are characterised by extreme seasonal variation in light and temperature which influences growth, maturation, condition and resource use of fishes. However, our understanding of how seasonal changes affect mercury concentrations of fishes is limited. We conducted a year-round study (3 ice-covered months, 3 open-water months) with open-water inter-annual aspect (3 years: samples from August/September), focusing on total mercury (THg) concentrations and ecological characteristics of a common freshwater fish, European whitefish (Coregonus lavaretus (L.)) from a subarctic lake. We measured THg concentrations from tissues with fast (liver, n = 164) and moderate (muscle, n = 225) turnover rates, providing information on THg dynamics over different temporal scales. In both tissues, lipid-corrected THg concentrations were highest in winter (liver: 1.70 ± 0.88 μg/g, muscle: 0.24 ± 0.05 μg/g) and lowest in summer (liver: 0.87 ± 0.72 μg/g, muscle: 0.19 ± 0.04 μg/g). THg concentrations increased in winter following the summer-autumn dietary shift to pelagic zooplankton and starvation after spawning. Whitefish THg concentrations decreased towards summer, and were associated with consumption of benthic macroinvertebrates and subsequent growth dilution. Mercury bioaccumulated in both tissues with age, both showing the strongest regression slopes in winter and lowest in summer. THg concentrations in liver and muscle tissue were correlated throughout the year, however the correlation was lowest in summer, indicating high metabolism during somatic growing season in summer and growth dilution. Multiple linear regression models explained 50% and 55% of the THg variation in liver and muscle both models dominated by seasonally-variable factors i.e. sexual maturity, δ13C, and condition factor. Seasonally varying bioaccumulation slopes and the higher level of intra-annual variation (21%) in whitefish THg concentration in muscle than the inter-annual accumulation (8%) highlight the importance of including seasonal factors in future THg studies.