Glyphosate-based herbicides (GBH) are the most widely used pesticides in the world. The extensive use of them increases the potential human health risk, including the human inhalation toxicity risk. We studied the effect of the most famous GBH Roundup® (RDP) in the concentration range from 50 to 125 μg/mL on Mitochondria-Associated apoptosis and DNA damage in Human alveolar carcinoma cells (A549 cells). Alkaline comet assay, immunofluorescence assay and Flow Cytometric Analysis assay were employed to detect DNA damages and apoptosis of A549 cells. We found RDP caused concentration-dependent increases in DNA damages and proportion of apoptotic cells in A549 cells. RDP induced the DNA single-strand breaks and double-strand breaks; the collapse of mitochondrial membrane by increasing Bax/Bcl-2, resulting in the release of cytochrome c into cytosol and then activated caspase-9/-3, cleaved poly (ADP-ribose) polymerase (PARP) in human lung tissue cells. The results demonstrate that RDP can induce A549 cells cytotoxic effects in vitro at the concentration lower than the occupational exposures level of workers, which means RDP has a potential threat to human health.

Historical increases in emissions and atmospheric deposition of oxidized and reduced nitrogen (N) provided the impetus for extensive, global-scale research investigating the effects of excess N in terrestrial and aquatic ecosystems, with several regions within the Eastern Deciduous Forest of the United States found to be susceptible to negative effects of excess N. The Clean Air Act and associated rules have led to decreases in emissions and deposition of oxidized N, especially in eastern U.S., representing a research challenge and opportunity for ecosystem ecologists and biogeochemists. The purpose of this paper is to predict changes in the structure and function of North American forest ecosystems in a future of decreased N deposition. Hysteresis is a property of a system wherein output is not a strict function of corresponding input, incorporating lag, delay, or history dependence, particularly when the response to decreasing input is different from the response to increasing input. We suggest a conceptual hysteretic model predicting varying lag times in recovery of soil acidification, plant biodiversity, soil microbial communities, forest carbon (C) and N cycling, and surface water chemistry toward pre-N impact conditions. Nearly all of these can potentially respond strongly to reductions in N deposition. Most responses are expected to show some degree of hysteresis, with the greatest delays in response occurring in processes most tightly linked to “slow pools” of N in wood and soil organic matter. Because experimental studies of declines in N loads in forests of North America are lacking and because of the expected hysteresis, it is difficult to generalize from experimental results to patterns expected from declining N deposition. These will likely be long-term phenomena, difficult to distinguish from other, concurrent environmental changes, including elevated atmospheric CO₂, climate change, reductions in acidity, invasions of new species, and long-term vegetation responses to past disturbance.

In this study, we carried out high time-resolution measurements of particle number concentration and size distribution (5–1000 nm) in Singapore, which represents a tropical urban environment. The measurements were taken during the southwest monsoon season in 2017 using a fast-response differential mobility spectrometer at a sampling rate of 1 Hz. In the measurement, short-lived nucleation events were found prominent at early afternoon because of the abundant incoming radiation that enhances the photochemical reactions in atmosphere. For the first time in the region, a five-factor positive matrix factorization approach was applied to the size spectra data. Based on particle number concentration, two sources within nucleation mode (<30 nm) were resolved and account for 43% of total number concentration, which is higher than the available monitoring data in other big cities. Among the sources, O₃-related atmospheric photochemical reactions with peak size at 10–12 nm is a unique factor and prominent in early afternoon nucleation events. The findings of this work can serve as a baseline for assessing influence of local and cross-border airborne emissions during various seasons in the future.

Polycyclic aromatic hydrocarbons (PAHs) in urban soils are a risk to the health of residents. To predict those risks, the distribution and the factors influencing the concentration of PAHs were studied by collecting 1120 records of soil PAHs published during 2006–2017 from 26 cities. The mean concentrations of 16 PAHs (∑PAHs) in soil varied from 123 μg/kg to 5568 μg/kg, with a mean value of 1083 μg/kg, suggesting that a few cities were polluted. The distribution of ∑PAHs in the cities followed two gradients, namely from northern China through eastern China to southern China and from industrial cities through developed cities to cities that are main tourist attractions. The concentrations were significantly correlated to annual temperature, the efficiency of energy use, and to such measures of air quality as PM₁₀ and NO₂ concentrations. A regression equation developed to predict the concentration of ∑PAHs in soil and the corresponding health risks to residents of 35 major Chinese cities of China showed that the risks to adults and children were slight in most cities but those in a few industrial cities were of concern, and field investigations are recommended to assess the risk in greater detail. The method offers a useful tool for predicting such risks in other cities even when data on soils PAHs are not available.

We investigate the distribution and effects of polystyrene microplastic (MP) particles in exposure experiments with the ecotoxicology model organism Daphnia magna. The aim was to investigate the short and long-term toxicity of MP at different concentrations. To achieve this goal, the effects of 6 μm commercially available polystyrene beads on two different life-stages of D. magna: < 24 h old juveniles and 9 days old adults was assessed. The following end points in test animals were measured: (1) survival, (2) growth, (3) individual and population fecundity, (4) age at maturation and (5) body size of newborn offspring. These response variables were followed in two acute and two chronic experiments. The acute experiments showed that MP is not acutely toxic to D. magna within 48 h, but cause added mortality within 120 h. The juveniles were about 50% more sensitive than the adults tested. In life-cycle experiments testing chronic exposure to MP, again, animals exposed as juveniles at relatively high concentrations, i.e. > 30 μg ml⁻¹ showed higher sensitivity. We observed slightly increased mortality, reduced growth and stimulation of early reproduction at the cost of later reproduction. Animals exposed after reaching adulthood did not show increased mortality and showed a stimulation response with higher reproductive rates than the control group. However, both the growth rate of mother animals and the body size of newborn declined with increasing dose of MP. We conclude that these effects indicate a role of MP in mechanical interaction/interference with the animal on the level of feeding (clogging filtering functions), digestion (gut filled with plastic particles), and/or other animal behavior. The study also illustrates how MP with slow break-down rates may accumulate in the environment and enter the food-chain as obstructing non-food particles in filter-feeding organisms.

Per- and polyfluoroalkyl Substances (PFAS) are ubiquitous in the environmental matrix, and their eco-toxicity on wide life and health risks on humans arising concerns. Due to the information gap, current risk assessments of PFAS ignore the indoor exposure pathway such as indoor dust and the different sources of drinking water. We collected and analyzed 168 indoor dust and 27 drinking water samples (including tap water, filtered water and bottled water). The mean concentrations of six typical PFAS measured in indoor dust and drinking water are in the range of 15.13–491.07 ng g⁻¹ and 0.31–4.14 ng L⁻¹, respectively. For drinking water, PFOA and PFOS were the dominant compounds, while PFHxS was the most abundant in indoor dust. Short-chain PFAS concentrations were higher than long-chain PFAS in both drinking water and indoor dust. Higher concentration of PFAS was observed in tap water and filtered water than bottled water. The total daily intake (TDI) of six PFAS are 20.67–52.97 ng kg⁻¹ d⁻¹ for infants, children, teenagers, and adults. As to children, teenagers, and adults, perfluorooctanoate (PFOA) is the major compound, accounting for 72.9–74.7% of the total daily intake. And PFOA (38.7%) and perfluorooctane sulfonate (PFOS, 42.2%) are the dominant PFAS for infants. The quantitative proportions of exposure sources are firstly revealed in this study, which in the order of foodstuff > indoor dust > drinking water > indoor air. Although the contribution to the PFAS intake of drinking water and indoor dust was not predominant (<9%), the health risks caused by long-term exposure need our attention. The hazard quotient (HQ) values of total PFAS were in the range of 0.154–0.498, which suggesting the relatively lower exposure risk in Chinese population. This study provides important reference to understand PFAS exposure status other than foodstuff.

Microplastics exhibit active environmental behavior and unique surface characteristics, and act as carriers for the migration of trivalent arsenic (As(III)) in the environment. Herein, the mechanism by which polytetrafluoroethylene (PTFE) microplastic particles adsorb As(III) is systematically determined. The larger the size of PTFE particles, the smaller the specific surface area, the higher the point of zero charge (PZC), and the more unfavorable adsorption of As(III); the highest adsorption amount can reach 1.05 mg g⁻¹. The adsorption process can be divided into three stages by the intraparticle diffusion model: external mass transfer, intraparticle diffusion, and dynamic equilibrium, of which the external mass transfer stage is the adsorption rate-limiting stage. The Langmuir isotherm model better represented the equilibrium adsorption results. The adsorption of As(III) by PTFE was an exothermic process, and because the increase in temperature broke the hydrogen bond, the amount of adsorption was decreased, which was not conducive to spontaneous adsorption. In the pH range of 3–7, as the pH value increased, the amount of As(III) adsorbed by PTFE gradually decreased, which may be related to the change in PZC for PTFE and the protonation of As(III). The H on the surface hydroxyl group of the PTFE exhibited a very large positive potential (+82.37 kcal mol⁻¹). Thus, it can attract the arsenic oxyanion, and As(III) was subsequently adsorbed on the surface of the PTFE through the hydrogen bond on the hydroxyl group. Electrostatic force and non-covalent interaction were the key mechanisms affecting the PTFE adsorption.

Microplastics (synthetic polymers <5 mm) have been recently recognized as a big environmental concern, as their ubiquity is an undeniable fact. Their wide variety regarding shapes, sizes, and materials turn them into an intrinsically risky pollutant capable of causing several environmental impacts. Textile microfibers (MF) are a microplastic sub-group. These are mostly shed when a normal laundry of any garment takes place. Special attention has been put onto them, as high concentrations have been found in products for human consumption as shellfish and tap water. However, as there is no consensus on the methodologies to quantify and report the results of MFs detached from textile garments, the degree of similarity between published studies is very low. Hence, the aim of this research was to evaluate the microfibers’ detachment rates of finished garments and to provide a set of comparable units to report the results. These were found to range between 175 and 560 MF/g or 30000–465000 MF/m² of garment. In addition, there was a high correlation between the MF detachment and the textile article superficial density. Finally, our results were compared with a recent paper that estimated the annual mass flow of MFs to the oceans. This previous publication is 30 times higher when related to the mass but 40 times lower if related to the number of MFs.

Atmospheric mercury (Hg) poses human health and ecological risks once deposited and bio-accumulated through food chains. Source contribution analysis of Hg deposition is essential to formulating emission control strategies to alleviate the adverse impact of Hg release from anthropogenic sources. In this study, a Hg version of California Puff Dispersion Modeling (denoted as CALPUFF-Hg) system with added Hg environmental processes was implemented to simulate the Hg concentration and deposition in the central region of the Pearl River Delta (cPRD) at 1 km × 1 km resolution. The contributions of eight source sectors to Hg deposition were evaluated. Model results indicated that the emission from cement production was the largest contributor to Hg deposition, accounting for 13.0%, followed by coal-fired power plants (6.5%), non-ferrous metal smelting (5.4%), iron and steel production (3.5%), and municipal solid waste incineration (3.4%). The point sources that released a higher fraction of gaseous oxidized mercury, such as cement production and municipal solid waste incineration, were the most significant contributors to local deposition. In this intensive industrialized region, large point sources contributed 67–94% of total Hg deposition of 6 receptors which were the nearest grid-cells from top five Hg emitters of the domain and the largest municipal solid waste incinerator in Guangzhou. Based on the source apportionment results, cement production and the rapidly growing municipal solid waste incineration are identified as priority sectors for Hg emission control in the cPRD region.

Polychlorinated biphenyls (PCBs) are a class of persistent organic pollutants that have been shown to be related to the occurrence of type 2 diabetes mellitus (T2DM). Nevertheless, it is necessary to further explore the development of T2DM caused by PCBs and its underlying mechanisms. In the present study, 21-day-old C57BL/6 male mice were orally treated with Aroclor 1254 (0.5, 5, 50 or 500 μg kg−1) once every three days. After exposure for 66 d, the mice showed impaired glucose tolerance, 13% and 14% increased fasting serum insulin levels (FSIL), and 63% and 69% increases of the pancreatic β-cell mass in the 50 and 500 μg kg−1 groups, respectively. After stopping exposure for 90 d, treated mice returned to normoglycemia and normal FSIL. After re-exposure of these recovered mice to Aroclor 1254 for 30 d, fasting plasma glucose showed 15%, 28% and 16% increase in the 5, 50 and 500 μg kg−1 treatments, FSIL exhibited 35%, 27%, 30% and 32% decrease in the 0.5, 5, 50 or 500 μg kg−1 groups respectively, and there was no change in pancreatic β-cell mass. Transcription of the pancreatic insulin gene (Ins2) was significantly down-regulated in the 50 and 500 μg kg−1 groups, while DNA-methylation levels were simultaneously increased in the Ins2 promoter during the course of exposure, recovery and re-exposure. Reduced insulin levels were initially rescued by a compensative increase in β-cell mass. However, β-cell mass eventually failed to make sufficient levels of insulin, resulting in significant increases in fasting blood glucose, and indicating the development of T2DM.