Mobile monitoring is an useful approach for measuring intra-urban variation of air pollution in urban environments. In this study, we used a mobile monitoring approach to study the spatial-temporal variability of air and noise pollution in urban neighborhoods of Philadelphia. During summer 2017, we used portable instruments to measure PM2.5, black carbon (BC), and noise levels along 5 km paths in four residential neighborhoods (Tioga, Mill Creek, Chestnut Hill, and Northern Liberties) and one commercial district (Center City) in Philadelphia, Pennsylvania, USA. A total of 62 sets of measurements were made at three different times of day (during morning rush hour, mid-afternoon, and during afternoon rush hour) from June 5 to July 7, 2017. Spatially, there was a significant difference in PM2.5 concentrations among the four residential neighborhoods. Overall, the Chestnut Hill neighborhood had the highest PM2.5 concentrations (13.25 ± 6.89 μg/m3), followed by Tioga (9.58 ± 4.83 μg/m3), Northern Liberties (7.02 ± 4.17 μg/m3), and Mill Creek (3.9 ± 4.5 μg/m3). There was temporal variability of pollutants depending on the neighborhood; Northern Liberties demonstrated the highest temporal variability in these data. The highest PM2.5 (18.86 ± 3.17 μg/m3) was measured in the Chestnut Hill neighborhood during morning rush hour. Mean PM2.5, BC, and noise levels based on mobile measurements at Philadelphia during summer 2017 were 8.41 ± 4.31 μg/m3, 0.99 ± 0.44 μg C/m3, and 62.01 ± 3.20 dBA, respectively. Environmental noise showed the highest temporal variation of the monitored components for 3 time periods. Generally, an increase in tree cover led to a decrease in PM2.5.

This paper reports the results of a joint project carried out by three regional environmental agencies of Italy to evaluate long-range mercury (Hg) transport from the abandoned Mt. Amiata Hg district in southern Tuscany (the third largest worldwide site for Hg production) to the fluvial ecosystems of the Paglia and Tiber rivers. Most of the work focused on stream sediments, surface waters and soils. A preliminary survey of Hg0 content in air was also conducted. Data obtained by public health authorities on Hg in vegetables and fish were also included.The highest Hg concentrations (up to thousands of μg/g Hg) were observed in stream sediments and soils directly impacted by Hg mine runoff. Although progressive Hg dilution was observed from north to south along the river, sediments and soils show anomalous Hg levels for over 200 km downstream of Mt. Amiata, testifying to an extreme case of long-range Hg contamination. A pervasive redistribution of Hg is observed in all sediment compartments. Presumably, the width of the impacted fluvial corridor corresponds to the entire alluvial plains of the rivers. The floodplains can be considered new sources for downstream Hg redistribution, especially during large flood events. On the other hand, results from water, air, and vegetable sampling indicate low potential for human exposure to Hg.The extent and distribution of the contamination makes remediation not viable. Therefore, people and human activities must coexist with such an anomaly. On the technical side, the most urgent action to be taken is better definition of the exact extent of the contaminated area. On the management side, it is necessary to identify which public institution(s) can best deal with such a widespread phenomenon. According to the precautionary principle, the impact of the contamination on human activities in the affected areas should be considered.

A sediment core was obtained from Moira Lake to study the legacy of contamination and remediation at the Deloro industrial site which includes 95-years of operations involving gold mining, mineral processing, and arsenic-based pesticide production resulting in high levels of arsenic, cobalt, and nickel. A timeline for the sediment core was established by ²¹⁰Pb dating and used to evaluate the geochemical record and the impact on primary production and subfossil cladocerans. In the early 1800s, there was an initial increase in the arsenic, cobalt and nickel concentrations due to industrial development. By the 1850s, the rate of enrichment increased due to the conglomeration of small-scale operations. In the 1960s, the concentrations of those metal(loid)s decreased following the cessation of the industrial activity at Deloro and the initiation of a clean-up effort. Primary production, inferred by chlorophyll-a concentrations, initially decreased as the metal(loid)s concentrations increased. This was followed by a recovery of the chlorophyll-a concentrations and further increases in production to higher levels than recorded prior to the Deloro years. Secondary production, inferred by cladoceran assemblage structure, was initially dominated by bosminids. The assemblage then changed to one dominated by chydorids and daphnids with the change occurring contemporaneous with the change in chlorophyll-a. However, the changes in primary and secondary production occurred during the period of accelerated metal(loid) enrichment, suggesting limited impact of contamination on primary and secondary producers. Loss on ignition results revealed that during the period of accelerated arsenic enrichment, the carbonate content of the sediments increased while the percent organic content decreased. This work contributes to ongoing research to establish the environmental legacy of historical industrial activities within complex ecosystems. Furthermore, the combination of geochemical (i.e. ²¹⁰Pb, ICP-OES, XANES) and ecological analysis provides a more complete picture of the complex interactions that have occurred in Moira Lake.

Accurately predicting the accumulation and toxicity of metals in organisms is a challenging work in ecotoxicology. Here, we developed and validated a physiologically based toxicokinetic and toxicodynamic (PBTK-TD) model for adult zebrafish exposed to Cd and Pb. The model included the gill, liver, intestine, gonad, carcass, and brain, which were linked by blood circulation in the PBTK process and by dynamic relationships between the target organ concentrations and mortality in the TD process. Results showed that the PBTK sub-model can accurately describe and predict the uptake, distribution and disposition kinetics of Cd and Pb in zebrafish. The exchange rates and the accumulation of the metals in the organs were significantly different. For Cd, the highest exchange rate was between blood and liver, and the greatest accumulation of Cd occurred in the liver. For Pb, the greatest accumulation occurred in the gill. The TD sub-model further indicated that metal concentrations in the gill may effectively act as more suitable indicator of Cd and Pb toxic effect than whole body or other organs. The proposed PBTK-TD model is helpful to understanding the fundamental processes by which zebrafish regulate the uptake and disposition of metal and to quantitatively predicting metal toxicity.

Bats are particularly suited as bioindicators of trace element pollution due to their longevity and their position in the trophic chain. In this study, the concentrations of ten non-essential trace elements (Al, As, Ba, Cd, Hg, Pb, Sb, Sr, Th, Tl) were determined in the tissues (whole body, skin-fur, skinned body, liver, kidney and bone) of lactant Tadarida teniotis from a nursery colony in Rome. A large number of bats from this nursery died before fledging and had bone deformities and fractures. The concentrations of non-essential trace elements in bone and whole body were also analysed in adult specimens of Miniopterus schreibersii from a colony located in a natural park in Northern Italy. In lactant T. teniotis, the Pb concentration decreased in the following order: bone>liver>skinned body>whole body>skin-fur>kidney, and exceeded the toxic threshold associated with negative effects reported for different mammalian species. The levels of the other non-essential trace elements were within a range indicative of low environmental contamination in both species. Significant interspecies differences (P < 0.05) were observed for concentrations of Pb and Ba, higher in the bones of T. teniotis, and of Cd, Hg and Sr, higher in the bones of M. schreibersii. In lactant T. teniotis, the different sources of Pb exposure, through inhalation and/or food, may represent a potential threat to the colony of this synanthropic European bat.

The continued increase in the global demand for oil, which reached 4,488 Mtoe in 2018, leads to large quantities of petroleum products entering the environment posing serious risks to natural ecosystems if left untreated. In this study, we evaluated the impact of co-contamination with lead on the efficacy of two bioremediation processes, natural attenuation and biostimulation of Total Petroleum Hydrocarbons (TPH) as well as the associated toxicity and the changes in the microbial community in contaminated soils. The biostimulated treatment resulted in 96% and 84% reduction in TPH concentration in a single and a co-contamination scenario, respectively, over 28 weeks of a mesocosm study. This reduction was significantly more in comparison to natural attenuation in a single and a co-contamination scenario, which was 56% and 59% respectively. In contrast, a significantly greater reduction in the associated toxicity of in soils undergoing natural attenuation was evident compared with soils undergoing biostimulation despite the lower TPH degradation when bioassays were applied. The earthworm toxicity test showed a decrease of 72% in the naturally attenuated toxicity versus only 62% in the biostimulated treatment of a single contamination scenario. In a co-contamination scenario, toxicity decreased only 30% and 8% after natural attenuation and biostimulation treatments, respectively. 16s rDNA sequence analysis was used to assess the impact of both the co-contamination and the bioremediation treatment. NGS data revealed major bacterial domination by Nocardioides spp., which reached 40% in week 20 of the natural attenuation treatment. In the biostimulated soil samples, more than 50% of the bacterial community was dominated by Alcanivorax spp. in week 12. The presence of Pb in the natural attenuation treatment resulted in an increased abundance of a few Pb-resistant genera such as Sphingopyxis spp. and Thermomonas spp in addition to Nocardioides spp. In contrast, Pb co-contamination completely shifted the bacterial pattern in the stimulated treatment with Pseudomonas spp. comprising approximately 45% of the bacterial profile in week 12. This study confirms the effectiveness of biostimulation over natural attenuation in remediating TPH and TPH-Pb contaminated soils. In addition, the presence of co-contaminants (e.g. Pb) results in serious impacts on the efficacy of bioremediation of TPH in contaminated soils, which must be considered prior to designing any bioremediation strategy.

The ground-level ozone (O₃) concentration in the urban regions of China has become an increasingly noticeable environmental problem in recent years. Many epidemiological studies have reported the association between O₃ pollution and mortality, only a few studies have focused on the O₃-related mortality and corresponding economic effects at the Chinese city and province level. This study reports the seasonal variation of ground-level O₃ in 338 cities of China during the year 2016 and evaluates its effect on premature mortality and economic loss. It further illustrates the differences in cause-specific mortality outcomes of the log-linear and linear model, two of the prominently used methods for estimating health effects. In 2016, the annual average daily maximum 8-h O₃ concentration in China ranged between 74 and 201 μg/m³ (138 ± 24.7 μg/m³). 30% of the total population was exposed to >160 μg/m³ O₃ concentration (Chinese national ambient air quality standard) and about 67.2% urban population lived in exposure above the WHO recommended O₃ concentrations (100 μg/m³). The estimated national O₃-attributable mortality was 74.2 × 10³ (95% CI: 16.7×10³–127×10³) in the log-linear model, whereas, the total O₃-related mortality using the linear model was 69.6 × 10³ (95% CI: 16.2 × 10³–115 × 10³). The exposure to O₃ caused a nationwide economic loss of about 7.6 billion US$ (range: 1.7–12.9) in 2016. This study uniquely provides most comprehensive coverage of the Chinese cities for O₃ associated mortality utilizing ground level measurement data for 2016 and presents a measurable assessment to the policymakers of China for streamlining their efforts on air quality improvement and O₃ containment.

Urban heat island (UHI), an iconic consequence of anthropogenic activities and climate condition, affects air pollution, energy use, and health. Therefore, better understanding of the temporal dynamics of UHI is required for sustainable urban planning to mitigate air pollution under a changing climate. Here, we present the evolution of UHI intensity (UHIi) and its controlling factors in the Seoul metropolitan area, Korea, over the last 56 years (1962–2017), which has experienced unique compressed economic growth and urban transformation under monsoon climate. The analysis demonstrated an inverted U-shape long-term variation of UHIi with the progress of urban transformation and economic climate which has not been reported in Asian cities before. Meanwhile, short-term variations in UHIi are related to both diurnal temperature range and duration after rainfall event unlike previous studies, and the UHIi was exacerbated by heat waves. Our findings suggest that the UHIi will exhibit different temporal dynamics with future changes in the monsoon climate, and heat waves in the urban area will be reinforced if current rapid urbanization continues without a shift toward sustainable and equitable development. Asian cities that are likely to face the similar urbanization trajectory and the implications are that urban (re)development strategy considers changes in rainfall magnitude and timing due to monsoon system variation under changing climate and plans to mitigate synergy between heat wave and UHI in this area.

Estimation of mercury (Hg) species fluxes in Hg contaminated rivers is crucial to predict Hg methylation in connected sediment sinks. Cinnabar (HgS) was mined and roasted for ∼500 years in the Idrija mining area, Slovenia, which is drained by the Idrijca River to the Gulf of Trieste (GT), Italy. Mining residues dumped into the Idrijca River caused high proportions of cinnabar in sediments, whereas soils containing high proportions of natural organic matter bound to Hg (NOM-Hg) are attributed to atmospheric Hg deposition. Previous calculations of Hg fluxes have been based on the erosion of cinnabar only, and neglected transport of NOM-Hg derived from soil. Here, we estimated NOM-Hg and cinnabar fluxes in the Idrijca River and evaluated the extent of variability under changing hydrological conditions. We estimated the discharge of NOM-Hg by Idrijca's tributaries and the importance of NOM-Hg fluxes for Hg methylation in the GT. Mass balance calculations reveal that approximately 11.2 Mg y⁻¹ of NOM-Hg and 38.9 Mg y⁻¹ of cinnabar are transported by the Idrijca River to the GT under median-flow conditions. In the past 520 years, a total of 53,000 tons of Hg have been released from the Idrija mining area, of which ∼32,000 tons were NOM-Hg. Under low-flow conditions, Idrijca's tributaries deliver more than 1280 kg y⁻¹ of NOM-Hg. This study highlights the importance of Hg species analyses and their flux calculations to estimate risks of biological Hg uptake in sedimentary Hg sinks connected to Hg mining areas.

There is a growing conservation concern about the possible consequences of environmental contamination in the health of bat communities. Most studies on the effects of contaminants in bats have been focused on organic contaminants, and the consequences of bat exposure to metals and metalloids remain largely unknown. The aim of this study was to evaluate the suitability of external biological matrices (fur and wing membrane) for the assessment of exposure and bioaccumulation of metals in bats. The concentration of arsenic, cadmium, cobalt, chromium, copper, manganese, nickel, lead, selenium and zinc was measured in internal organs (liver, heart, brain), internal (bone) and external tissues (wing membrane, fur) collected from bat carcasses of four species (Hypsugo savii, Nyctalus leisleri, Pipistrellus pipistrellus, Pipistrellus pygmaeus) obtained in windfarm mortality searches. With the exception of zinc (P = 0.223), the results showed significant differences between the concentrations of metals in the analyzed tissues for all metals (P < 0.05). Significant differences were also found between organs/tissues (P < 0.001), metals (P < 0.001) and a significant interaction between organs/tissues and metals was found (P < 0.001). Despite these results, the patterns in terms of metal accumulation were similar for all samples. Depending on the metal, the organ/tissue that showed the highest concentrations varied, but fur and wing had the highest concentrations for most metals. The variability obtained in terms of metal concentrations in different tissues highlights the need to define standardized methods capable of being applied in monitoring bat populations worldwide. The results indicate that wing membrane and fur, biological matrices that may be collected from living bats, yield reliable results and may be useful for studies on bats ecotoxicology, coupled to a standardized protocol for large-scale investigation of metal accumulation.