This technique for setting guideline values differs from that currently used by regulatory agencies throughout the world. Data for benzene were evaluated from epidemiological studies on human populations (29 studies). Exposure durations were evaluated in terms of Long Term Exposure (LTE) and Lifetime Exposure. All data was reported as Lowest Observed Adverse Effect Levels (LOAEL) and converted into exposure doses using Average Daily Dose (ADD) and Lifetime Average Daily Dose (LADD). These values were plotted as a Toxicant Sensitivity Distribution (TSD) which was the cumulative probability of LOAEL-ADD and LOAEL-LADD. From the TSD plots, linear regression equations gave correlation coefficients (R2) ranging from 0.69 to 0.97 indicating normal distributions. Guideline Values (GVs) for LTE (8hr/day) and Lifetime (24hr/70yrs) exposure to benzene were calculated using data from human epidemiological studies as 5% level of cumulative probability (CP) of LOAEL–ADD and LOAEL–LADD from the cumulative probability distributions (CPD). The derived guideline values from the human epidemiological studies were 92 μg/kg/day for LTE and 3.4 μg/kg/day for lifetime exposure. GV for LTE is appropriate for occupational exposure and GV derived for lifetime exposure appropriate for the general population. The guideline value for occupational exposure limit was below all the guideline values developed by regulatory agencies. But the general population guideline is within the range of values formulated by European Union, ATSDR, EPAQS, USEPA and OEHHA for air quality for the general population. This is an alternative method which eliminates the application of safety factors and other sources of errors in deriving guideline values for benzene.

To monitor the body burden of persistent organic pollutants in mothers and infants living in proximity to a 10-year-old municipal waste incinerator (MWI), levels of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs) in the breast milk of mothers were evaluated, and the estimated daily intake (EDI) level of these pollutants in infants was assessed. In total, 14 mothers from the exposure area and 18 mothers from a control area were recruited for this study. In addition, the levels of 17 PCDD/F congeners and 18 PCB congeners in the breast milk of the mothers were estimated, and risk assessment for their infants by calculating their EDI levels was performed. The mean levels of ΣPCDD/Fs and TEQ-ΣPCDD/Fs in the breast milk of the exposure group were significantly greater than those of the control group (3.36 vs. 1.47 pg/g wet weight; and 0.24 vs. 0.12 pg TEQ/g wet weight, respectively; p < 0.05). With respect to PCBs, the mean levels of the total PCBs (ΣPCBs) and non-dioxin like-PCBs (ΣNDL-PCBs) in the exposure group were significantly greater than those in the control group (269 vs. 141 pg/g wet weight; 230 vs. 115 pg/g wet weight, respectively; p < 0.05). The mean levels of ΣPCDD/Fs and TEQ-ΣPCDD/Fs were positively correlated with the inhabit time of the exposure group (r = 0.636, r = 0.629, p < 0.05, respectively). The mean EDI level of the exposure group in infants was significantly greater than that of the control group (22.0 vs. 13.0 pg TEQ/kg bw day; p < 0.05). In conclusion, mothers and their breast-fed infants living in proximity to the 10-year-old MWI located in the Zhejiang Province of China exhibited a significantly higher body burden of PCDD/Fs and PCBs compared to those living in the control area.

The performance, nitrogen removal rate, microbial enzymatic activity and extracellular polymeric substances (EPS) of activated sludge were assessed under nickel (Ni(II)) stress. The organic matter and NH₄⁺-N removal efficiencies were stable at less than 10 mg/L Ni(II) and subsequently decreased with the increment of Ni(II) concentration from 10 to 30 mg/L. The specific oxygen uptake rate and dehydrogenase activity kept stable at less than 5 mg/L Ni(II) and then declined at 5–30 mg/L Ni(II). Both specific ammonia-oxidizing rate (SAOR) and specific nitrite-oxidizing rate (SNOR) decreased with the increment of Ni(II) concentration. The changing trends of ammonia monooxygenase and nitrite oxidoreductase activities were matched those of SAOR and SNOR, respectively. The nitrite-reducing rate and nitrate-reducing rate illustrated a similar variation tendency to the nitrite reductase activity and nitrate reductase activity, respectively. Ni(II) impacted on the production, chemical composition and functional group of EPS. The relation between the sludge volume index and the EPS production exhibited a better linear function with a negative slope, demonstrating that Ni(II) improved the sludge settleability despite of the increase of EPS production.

Glyphosate, as a broad-spectrum herbicide, is frequently detected in water and several studies have investigated its effects on several freshwater aquatic organisms. Yet, only few investigations have been performed on marine macroalgae. Here, we studied both the metabolomics responses and the effect on primary production in the endemic brown algae Fucus virsoides exposed to different concentration (0, 0.5, 1.5 and 2.5 mg L⁻¹) of a commercial glyphosate-based herbicide, namely Roundup®. Our results show that Roundup® significantly reduced quantum yield of photosynthesis (Fᵥ/Fₘ) and caused alteration in the metabolomic profiles of exposed thalli compared to controls. Together with the decrease in the aromatic amino acids (phenylalanine and tyrosine), an increase in shikimate content was detected. The branched-amino acids differently varied according to levels of herbicide exposure, as well as observed for the content of choline, formate, glucose, malonate and fumarate. Our results suggest that marine primary producers could be largely affected by the agricultural land use, this asking for further studies addressing the ecosystem-level effects of glyphosate-based herbicides in coastal waters.

Light at night (LAN) negatively impacts the behaviour and physiology; however, very little is known about molecular correlates of LAN-induced effects in diurnal animals. Here, we assessed LAN-induced effects on behaviour and physiology, and examined molecular changes in the liver of diurnal zebra finches (Taeniopygia guttata). Birds were exposed to dim LAN (dLAN: 12L = 150 lux: 12D = 5 lux), with controls on 12L (150 lux): 12D (0 lux). dLAN altered daily activity-rest and eating patterns, induced nocturnal eating and caused body fattening and weight gain, and reduced nocturnal melatonin levels. Concomitant increased nighttime glucose levels, decreased daytime thyroxine and triglycerides levels, and hepatic lipid accumulation suggested the impairment of metabolism under dLAN. Transcriptional assays evidenced dLAN-induced negative effects on metabolism in the liver, the site of metabolic homeostasis. Particularly, increased g6pc and foxo1 mRNA expressions suggested an enhanced gluconeogenesis, while increased egr1 and star expressions suggested enhanced cholesterol biosynthesis and lipid metabolism, respectively. Similarly, overexpressed sirt1 indicated protection from the metabolic damage due to elevated gluconeogenesis and cholesterol biosynthesis under dLAN. However, no effect on genes involved in lipogenesis (fasn) and insulin signalling pathway (socs3 and insig1) might indicate for the post transcriptional/post translational modification effects or the involvement of other genetic pathways in LAN-induced effects. We also found daily rhythm in the hepatic expression of selected clock and clock-controlled genes (per2, bmal1 and reverb-beta), with an elevated mesor and amplitude of per2 oscillation, suggesting a role of per2 in the liver metabolism. These results demonstrate dLAN-induced negative effects on the behaviour and physiology, and provide molecular insights into metabolic risks of the exposure to illuminated nights to diurnal animals including humans in an urban setting.

Concerns regarding microplastic contamination have spread from aquatic environments to terrestrial systems with a growing number of studies have been reported. Notwithstanding, the potential effects on soil ecosystems remain largely unexplored. In this study, the effects of polyethylene microplastics on soil enzymatic activities and the bacterial community were evaluated, and the microbiota colonizing on microplastics were also investigated. Microplastic amendment (2000 fragments per kg soil) significantly increased the urease and catalase activities in soil after 15 days, and no discernible alteration of invertase activities was detected. Results from high-throughput sequencing of 16S rRNA revealed that the alpha diversities (richness, evenness, and diversity) of the microbiota in soil were not obviously changed by the PE amendment, whereas the diversity indexes of microbiota on plastic fragments were significantly lower than those in the control and amended soils. Different taxonomic composition was observed in between the control and amended soils after 90 days of incubation. Bacterial assemblages with distinct community structure colonized the PE microplastics. Additionally, several taxa including plastic-degrading bacteria and pathogens were more abundant on microplastics. Simultaneously, the predicted functional profiles showed that the pathways of amino acid metabolism and xenobiotics biodegradation and metabolism were higher on the microplastics. These results indicated that microplastics in soil, compared with those in aquatic environments, can also act as a distinct microbial habitat, potentially altering the ecological functions of soil ecosystems.

Changzhou, an industrial city in the Yangtze River Delta, has been experiencing serious haze pollution, particularly in winter. However, studies pertaining to the haze in Changzhou are very limited, which makes it difficult to understand the characteristics and formation of winter haze in this area, and develop effective control measures. In this study, we carried out continuous online observation of particulate matter, chemical components, and meteorology in Changzhou in February 2017. Our results showed that haze pollution occurred frequently in Changzhou winter and exhibited two patterns: dry haze with low relative humidity (RH) and wet haze with high RH. Water-soluble inorganic ions (SO₄²⁻, NO₃⁻, and NH₄⁺) accounted for ∼52.2% of the PM₂.₅ mass, of which sulfate was dominant in wet haze periods while nitrate was dominant in other periods. With the deterioration of haze pollution, the proportion of nitrate in PM₂.₅ increased, while sulfate proportion increased under wet haze and decreased under dry haze. Dry haze and wet haze appeared under slow north wind and south wind, respectively, and strong north wind or sea breeze scavenged pollution. We found that formation of nitrate occurred rapidly in daytime with high concentrations of odd oxygen (Oₓ = O₃ + NO₂), whereas formation of sulfate occurred rapidly during nighttime with high RH, indicating that photochemistry and heterogeneous reaction were the major formation mechanisms for nitrate and sulfate, respectively. Through the cluster analysis of 36-h backward trajectories, five sources of air masses from three directions were identified. High PM₂.₅ concentrations (84.1 μg m⁻³ on average) usually occurred under the influence of two clusters (46%) from the northwest, indicating that regional transport from northern China aggravated the winter haze pollution in Changzhou. Emission reduction, particularly the mobile sources, and regional joint prevention and control can help to mitigate the winter haze in Changzhou.

Water availability is paramount in the response of soil invertebrates towards stress situations. This study aimed to evaluate the effects of forecasted soil moisture scenarios on the avoidance behavior of two invertebrate species (the arthropod Folsomia candida and the soft-bodied oligochaete Enchytraeus crypticus) in soils degraded by different types of anthropogenic metal(loid) contamination (mining soil and agricultural soil affected by industrial chemical wastes). Different soil moisture contents (expressed as % of the soil water holding capacity, WHC) were evaluated: 50% (standard soil moisture conditions for soil invertebrates' tests); 75% (to simulate increasing soil water availability after intense rainfalls and/or floods); 40%, 30%, 25% and 20% (to simulate decreasing soil water availability during droughts). Invertebrates’ avoidance behavior and changes in soil porewater major ions and metal(loid)s were assessed after 48 h exposure. Soil incubations induced a general solubilization/mobilization of porewater major ions, while higher soil acidity favored the solubilization/mobilization of porewater metal(loid)s, especially at 75% WHC. Folsomia candida preferred soils moistened at 50% WHC, regardless the soils were contaminated or not and the changing soil porewater characteristics. Enchytraeus crypticus avoided metal(loid) contamination, but this depended on the soil moisture conditions and the corresponding changes in porewater characteristics: enchytraeids lost their capacity to avoid contaminated soils under water stress situations (75% and 20–25% WHC), but also when contaminated soils had greater water availability than control soils. Therefore, forecasted soil moisture scenarios induced by global warming changed soil porewater composition and invertebrates capacity to avoid metal(loid)-contaminated soils.

The efficient removal of mercury from aqueous media remains a severe challenge in ensuring environmental safety, especially for low-concentration mercury, which requires adsorbents with high mercury affinity. In this work, we reported a nanocomposite of β-cyclodextrin and three-dimensional graphene (3D CD@RGO) to enhance the adsorption affinity and capacity for mercury with low concentrations. Characterization of the nanocomposite revealed that cyclodextrin was well dispersed on the 3D graphene support structure to provide highly exposed hydroxyl groups. Adsorption experiments showed that CD@RGO exhibited different adsorption behaviors for mercury within different concentration ranges of 0.2–4.0 mg/L and 4.0–10.0 mg/L, and the adsorption affinity for the former range (KL = 10.05 L/mg) was 1.5 times higher than that for the latter range (KL = 6.69 L/mg). Moreover, CD@RGO had a high adsorption efficiency of 96.6% with a superb adsorption affinity (172.09 L/g) at Ce = 0.01 mg/L, which is 6.70 and 41.25 times higher than that of RGO and RCD (physical mixture of RGO and cyclodextrin), respectively, indicating a synergistic effect of CD@RGO for mercury adsorption. This enhancement can be attributed to the transformation of the adsorption mechanism from the outer-sphere force of electrostatic interaction in RGO to the inner-sphere surface complexation in CD@RGO.

In this study, a proposed integrated high-gravity technology for air pollution control, CO2 capture, and alkaline waste utilization was comprehensively evaluated from engineering, environmental, and economic perspectives. After high-gravity technology and coal fly ash (CFA) leaching processes were integrated, flue gas air emissions removal (e.g., sulfate dioxide (SO2), nitrogen oxides (NOx), total suspended particulates (TSP)) and CO2 capture were studied. The CFA, which contains calcium oxide and thus, had high alkalinity, was used as an absorbent in removing air pollution residues. To elucidate the availability of technology for pilot-scale high-gravity processes, the engineering performance, environmental impact, and economic cost were simultaneously investigated. The results indicated that the maximal CO2, SO2, NOx, and TSP removal efficiencies of 96.3 ± 2.1%, 99.4 ± 0.3%, 95.9 ± 2.1%, and 83.4 ± 2.6% were respectively achieved. Moreover, a 112 kWh/t-CO2 energy consumption for a high-gravity process was evaluated, with capture capacities of 510 kg CO2 and 0.468 kg NOx per day. In addition, the fresh, water-treated, acid-treated, and carbonated CFA was utilized as supplementary cementitious materials in the blended cement mortar. The workability, durability, and compressive strength of 5% carbonated CFA blended into cement mortar showed superior performance, i.e., 53 MPa ±2.5 MPa at 56 days. Furthermore, a higher engineering performance with a lower environmental impact and lower economic cost could potentially be evaluated to determine the best available operating condition of the high-gravity process for air pollution reduction, CO2 capture, and waste utilization.