Plants growing in heavy-metal-rich soils can accumulate metals into their nectar. Nectar chemical composition can alter foraging behavior of floral visitors (including pollinators and floral antagonists) and further affect plant reproductive fitness. The role of nectar heavy metals in deterring pollinators (e.g., shortening foraging time) has been recently studied, but their effects on plant reproduction via changes in behaviors of both pollinators and floral antagonists (e.g., nectar robbers) are less understood. We experimentally manipulated four nectar heavy metals (Zn, Cu, Ni, and Pb) in a native ornamental plant, Hosta ensata F. Maekawa, to investigate the effect of nectar metals on plant reproductive success. We also recorded nectar robbing as well as foraging time and visitation rate of pollinators to assess whether nectar metals could alter the behavior of antagonists and mutualists. Although metals in nectar had no significant direct effects on plant reproduction via hand-pollination, we detected their positive indirect effects on components of female fitness mediated by pollinators and nectar robbers. Matching effects on female plant fitness, nectar robbers responded negatively to the presence of metals in nectar, robbing metal-treated flowers less often. Pollinators spent less time foraging on metal-treated flowers, but their visitation rate to metal-treated flowers was significantly higher than to control flowers. Moreover, pollinators removed less nectar from flowers treated with metals. Our results provide the first direct evidence to date that heavy metals in nectar are capable of deterring nectar robbers and modifying pollinator foraging behavior to enhance plant reproductive fitness.

Despite the extensive production and use of phthalates in Asian countries, especially China, limited information is available about the current situation of human exposure in this region, and thus identification of further research needs is warranted. This review summarized the current trends of phthalates related to industrial production and human exposure by conducting a comprehensive assessment of phthalates contaminations in air, indoor dust, personal care products (PCPs), foodstuff and internal exposure in China, with comparisons with other countries. The concentrations of phthalates in indoor dust and PCPs in China were moderate, while concentrations in foods and air were among the highest worldwide. Dietary intake of phthalates varied with location, with hotspots in the southern and eastern coastal regions of China which correlated with the extensive industrial production recorded in these regions. This review firstly revealed the significantly differentiated food-type contribution profiles for phthalates in China and in other countries, which were affected by dietary habits and food contamination. The internal exposure for the Chinese population was found to be moderate, however there is a paucity of data available. Knowledge gaps identified concerning phthalates in China include trends in phthalates exposure, sources (e.g. PCPs, pharmaceuticals and medical treatment), and internal exposure derived from biomonitoring, warranting phthalates a research priority.

Determining sources of heavy metals in soils, sediments and groundwater is important for understanding their fate and transport and mitigating human and environmental exposures. Artificially imported fill, natural sediments and groundwater from 240 ha of reclaimed land at Fishermans Bend in Australia, were analysed for heavy metals and other parameters to determine the relative contributions from different possible sources. Fishermans Bend is Australia's largest urban re-development project, however, complicated land-use history, geology, and multiple contamination sources pose challenges to successful re-development. We developed a method for heavy metal source separation in groundwater using statistical categorisation of the data, analysis of soil leaching values and fill/sediment XRF profiling. The method identified two major sources of heavy metals in groundwater: 1. Point sources from local or up-gradient groundwater contaminated by industrial activities and/or legacy landfills; and 2. contaminated fill, where leaching of Cu, Mn, Pb and Zn was observed. Across the precinct, metals were most commonly sourced from a combination of these sources; however, eight locations indicated at least one metal sourced solely from fill leaching, and 23 locations indicated at least one metal sourced solely from impacted groundwater. Concentrations of heavy metals in groundwater ranged from 0.0001 to 0.003 mg/L (Cd), 0.001–0.1 mg/L (Cr), 0.001–0.2 mg/L (Cu), 0.001–0.5 mg/L (Ni), 0.001–0.01 mg/L (Pb), and 0.005–1.2 mg/L (Zn). Our method can determine the likely contribution of different metal sources to groundwater, helping inform more detailed contamination assessments and precinct-wide management and remediation strategies.

Several studies have indicated the presence of contaminants in Alpine aquatic ecosystems. Even if measured concentrations are far below those that cause acute effects, continuous exposure to sub-lethal concentrations may have detrimental effects on the aquatic species present in these remote environments. This may lead to a cascade of indirect effects at higher levels of the ecological hierarchy (i.e., the community). To improve the determination of ecologically relevant risk endpoints, behavioural alterations in organisms due to pollutants are increasingly studied in ecotoxicology. In fact, behaviour links physiological function with ecological processes, and can be very sensitive to environmental stimuli and chemical exposure. This is the first study on behavioural alteration in a wild population of an Alpine species. In the present study, a video tracking system was standardized and subsequently used to identify contaminant-induced behavioural alterations in Diamesa zernyi larvae (Diptera, Chironomidae). Diamesa zernyi larvae, collected in an Italian Alpine stream (Rio Presena, Trentino Region), were acclimated for 24 h and successively exposed to several aquatic contaminants (pesticides: chlorpyrifos, metolachlor, boscalid, captan; pharmaceuticals: ibuprofen, furosemide, trimethoprim) at concentrations corresponding to their Lowest Observed Effect Concentration (LOEC). After 24, 48, 72, and 96 h of exposure, changes in the distance moved, the average speed, and the frequency of body bends were taken to reflect contaminant- and time-dependent effects on larval behaviour. In general, metolachlor, captan, and trimethoprim tended to reduce all the endpoints under consideration, whereas chlorpyrifos, boscalid, ibuprofen, and furosemide seemed to increase the distances moved by the larvae. This could be related to the different mechanisms of action of the investigated chemicals. Independently of the contaminant, after 72 h a general slowing down of all the behavioural activities occurred. Finally, we propose a behavioural stress indicator to compare the overall behavioural effects induced by the various contaminants.

Human exposure to neurotoxic pollutants (e.g. metals, pesticides and other chemicals) is recognized as a key risk factor in the pathogenesis of neurodegenerative disorders. Emerging evidence indicates that an alteration in autophagic pathways may be correlated with the onset of the neurotoxicity resulting from chronic exposure to these pollutants. In fact, autophagy is a natural process that permits to preserving cell homeostasis, through the seizure and degradation of the cytosolic damaged elements. However, when an excessive level of intracellular damage is reached, the autophagic process may also induce cell death. A correct modulation of specific stages of autophagy is important to maintain the correct balance in the organism. In this review, we highlight the critical role that autophagy plays in neurotoxicity induced by the most common classes of environmental contaminants. The understanding of this mechanism may be helpful to discover a potential therapeutic strategy to reduce side effects induced by these compounds.

Chemical mass balance (CMB) modeling and radiocarbon measurements were combined to evaluate the sources of carbonaceous fine particulate matter (PM2.5) in Shenzhen, China during and after the 2011 summer Universiade games when air pollution control measurements were implemented to achieve air quality targets. Ambient PM2.5 filter samples were collected daily at two sampling sites (Peking University Shenzhen campus and Longgang) over 24 consecutive days, covering the controlled and uncontrolled periods. During the controlled period, the average PM2.5 concentration was less than half of what it was after the controls were lifted. Organic carbon (OC), organic molecular markers (e.g., levoglucosan, hopanes, polycyclic aromatic hydrocarbons), and secondary organic carbon (SOC) tracers were all significantly lower during the controlled period. After pollution controls ended, at Peking University, OC source contributions included gasoline and diesel engines (24%), coal combustion (6%), biomass burning (12.2%), vegetative detritus (2%), biogenic SOC (from isoprene, α-pinene, and β-caryophyllene; 7.1%), aromatic SOC (23%), and other sources not included in the model (25%). At Longgang after the controls ended, similar source contributions were observed: gasoline and diesel engines (23%), coal combustion (7%), biomass burning (17.7%), vegetative detritus (1%), biogenic SOC (from isoprene, α-pinene, and β-caryophyllene; 5.3%), aromatic SOC (13%), and other sources (33%). The contributions of the following sources were smaller during the pollution controls: biogenic SOC (by a factor of 10–16), aromatic SOC (4–12), coal combustion (1.5–6.8), and biomass burning (2.3–4.9). CMB model results and radiocarbon measurements both indicated that fossil carbon dominated over modern carbon, regardless of pollution controls. However, the CMB model needs further improvement to apportion contemporary carbon (i.e. biomass burning, biogenic SOC) in this region. This work defines the major contributors to carbonaceous PM2.5 in Shenzhen and demonstrates that control measures for primary emissions could significantly reduce secondary organic aerosol (SOA) formation.

The prothrombotic effects of particulate matter (PM) may underlie the association of air pollution with increased risks of cardiovascular disease. This study aimed to investigate the association between long-term exposure to PM with an aerodynamic diameter ≤2.5 μm (PM2.5) and platelet counts, a marker of coagulation profiles.The study participants were from a cohort consisting of 362,396 Taiwanese adults who participated in a standard medical examination program between 2001 and 2014. Platelet counts were measured through Complete Blood Count tests. A satellite-based spatio-temporal model was used to estimate 2-year average ambient PM2.5 concentration at each participant's address. Mixed-effects linear regression models were used to investigate the association between PM2.5 exposure and platelet counts.This analysis included 175,959 men with 396,248 observations and 186,437 women with 397,877 observations. Every 10-μg/m3 increment in the 2-year average PM2.5 was associated with increases of 0.42% (95% CI: 0.38%, 0.47%) and 0.49% (95% CI: 0.44%, 0.54%) in platelet counts in men and women, respectively. A series of sensitivity analyses, including an analysis in participants free of cardiometabolic disorders, confirmed the robustness of the observed associations. Baseline data analyses showed that every 10-μg/m3 increment in PM2.5 was associated with higher risk of 17% and 14% of having elevated platelet counts (≥90th percentile) in men and women, respectively.Long-term exposure to PM2.5 appears to be associated with increased platelet counts, indicating potential adverse effects on blood coagulability.

Pulse diffusive nitrous oxide (N₂O) emission following water application is well documented, whereas N₂O emission caused by soil water-air displacement during the watering process (termed as soil degassing) has been largely overlooked. Watering-induced N₂O emissions from ten different soils in China were quantified, and found to range from 74.4 ± 6.7 to 678.1 ± 36.6 μg N₂O m⁻² h⁻¹ in surface watered (SW) soils, and from 45.6 ± 4.4 to 358.1 ± 23.6 μg N₂O m⁻² h⁻¹ in subsurface watered (SUW) soils. These N₂O fluxes were much larger than the diffusive N₂O flux from the same soil either under dry (7.9%–9.6% water filled pore space, WFPS) or wet (85.1%–93.6% WFPS) conditions. The watering process (the water infiltration process upon irrigation/rainfall or the process of shallow groundwater uplifting) resulted in massive N₂O emissions.

In Part II of this work we present the results of the downscaled offline Weather Research and Forecasting/Community Multiscale Air Quality (WRF/CMAQ) model, included in the “Technology Driver Model” (TDM) approach to future U.S. air quality projections (2046–2050) compared to a current-year period (2001–2005), and the interplay between future emission and climate changes. By 2046–2050, there are widespread decreases in future concentrations of carbon monoxide (CO), nitrogen oxides (NOx = NO + NO2), volatile organic compounds (VOCs), ammonia (NH3), sulfur dioxide (SO2), and particulate matter with an aerodynamic diameter ≤ 2.5 μm (PM2.5) due mainly to decreasing on-road vehicle (ORV) emissions near urban centers as well as decreases in other transportation modes that include non-road engines (NRE). However, there are widespread increases in daily maximum 8-hr ozone (O3) across the U.S., which are due to enhanced greenhouse gases (GHG) including methane (CH4) and carbon dioxide (CO2) under the Intergovernmental Panel on Climate Change (IPCC) A1B scenario, and isolated areas of larger reduction in transportation emissions of NOx compared to that of VOCs over regions with VOC-limited O3 chemistry. Other notable future changes are reduced haze and improved visibility, increased primary organic to elemental carbon ratio, decreases in PM2.5 and its species, decreases and increases in dry deposition of SO2 and O3, respectively, and decreases in total nitrogen (TN) deposition. There is a tendency for transportation emission and CH4 changes to dominate the increases in O3, while climate change may either enhance or mitigate these increases in the west or east U.S., respectively. Climate change also decreases PM2.5 in the future. Other variable changes exhibit stronger susceptibility to either emission (e.g., CO, NOx, and TN deposition) or climate changes (e.g., VOC, NH3, SO2, and total sulfate deposition), which also have a strong dependence on season and specific U.S. regions.