Diffusive gradients in thin films (DGT)-induced flux in sediments (DIFS) (DGT-DIFS) model for phosphorus (P) has been investigated to provide a numerical simulation of a dynamic system of the DGT–pore water–sediment in Dianchi Lake (China). Kinetic parameter—T C (33–56,060 s), distribution coefficient—K d (134.7–1536 cm³g⁻¹), and resupply parameter—R (0.189–0.743) are derived by DGT measurement, the sediment/pore water test, and the DIFS model. The changes of dissolved concentration in DGT diffusive layer and pore water and sorbed concentration in sediment, as well as the ratio of C DGT and the initial concentration in pore water (R) and mass accumulated by DGT resin (M) at the DGT–pore water–sediment interface (distance) of nine sampling sites during DGT deployment time (t) are derived through the DIFS simulation. Based on parameter and curves derived by the DIFS model, the P release-transfer character and mechanism in sediment microzone were revealed. Moreover, the DGT-DIFS parameters (R, T C , K ₋₁ , C DGT), sediment P pool, sediment properties (Al and Ca), and soluble reactive P (SRP) in overlying water can be used to assess “P eutrophication level” at different sampling sites with different types of “external P loading.” The DGT-DIFS model is a reliable tool to reveal the dynamic P release in sediment microzone and assess “internal P loading” in the plateau lake Dianchi.

We aimed at assessing the effects of four wetland plant species commonly used in constructed wetland systems: Typha, Phragmites, Iris and Juncus for removing ibuprofen (IBU) and iohexol (IOH) from spiked culture solution and exploring the mechanisms responsible for the removal. IBU was nearly completely removed by all plant species during the 24-day experiment, whereas the IOH removal varied between 13 and 80 %. Typha and Phragmites were the most efficient in removing IBU and IOH, respectively, with first-order removal rate constants of 0.38 and 0.06 day⁻¹, respectively. The pharmaceuticals were taken up by the roots and translocated to the aerial tissues. However, at the end of the experiment, plant accumulation constituted only up to 1.1 and 5.7 % of the amount of IBU and IOH spiked initially. The data suggest that the plants mainly function by facilitating pharmaceutical degradation in the rhizosphere through release of root exudates.

One technique applied to restore degraded or contaminated soils is to use amendments made of different types of waste materials, which in turn may contain metals such as Cu, Pb and Zn. For this reason, it is important to determine the capacity of the soil to retain these materials, and to compare the sorption capacity between an amended soil and another unamended soil. The aim of this study was to determine the mobility and availability of these metals in the soil after applying the amendment, and how it affected the soil’s sorption capacity. Sorption isotherms were compared with the empirical models of Langmuir and Freundlich to estimate the sorption capacity. The overall capacity of the soils to sorb Cu, Pb or Zn was evaluated as the slope Kr. The amendments used in this study were a mixture made of compost and biochar in different proportions (20, 40, 60, 100 %), which were applied to the mine tailing from a settling pond from a copper mine. The mine tailing that were amended with the mixture of compost and biochar had a higher sorption capacity than the mine tailing from the unamended pond, and their sorption isotherms had a greater affinity towards Cu, Pb and Zn than the mine tailing that was studied. Therefore, the results obtained show that adding a mixture of compost and biochar favours the retention of Cu, Pb and Zn in mine tailing.

Gas phase polycyclic aromatic hydrocarbons (PAHs) in Hexi Corridor, Northwest China were determined during heating and non-heating seasons, respectively, using passive air samplers. Polyurethane foam (PUF) disks were chosen as the sampling medium. Fifteen PAHs out of the 16 PAHs classified by the United States Environmental Protection Agency (U.S. EPA) were detected in this field sampling investigation. The atmospheric levels of sampled PAHs were higher at urban sites than that at rural sites among 14 sampling sites and increased during heating season. The highest concentration (11.34 ng m⁻³) was observed in Lanzhou during the heating season, the capital and largest industrial city of Gansu Province. PAH contamination in air was dominated by three aromatic ring congeners. Possible sources of PAHs were apportioned using PAH species ratios and the principle component analysis (PCA) combined with a multiple linear regression (MLR) method. Fossil fuel consumption was identified to be the predominant source of PAHs over Hexi Corridor, accounting for 43 % of the concentration of total (15) PAHs. Backward and forward trajectory and cluster analysis were also carried out to identify potential origins of PAHs monitored at several urban and rural sites. Lung cancer risk of local residents to gas phase PAHs via inhalation exposure throughout the province was found to be around a critical value of the lung cancer risk level at 10⁻⁶ recommended by the U.S. EPA risk assessment guideline.

The photodegradation of diethyl phthalate (DEP) by UV/H₂O₂ and UV/TiO₂ is studied. The DEP degradation kinetics and multiple crucial factors effecting the clearance of DEP are investigated, including initial DEP concentration ([DEP]₀), initial pH values (pH₀), UV light intensity, anions (Cl⁻, NO³⁻, SO₄ ²⁻, HCO₃ ⁻, and CO₃ ²⁻), cations (Mg²⁺, Ca²⁺, Mn²⁺, and Fe³⁺), and humic acid (HA). Total organic carbon (TOC) removal is tested by two treatments. And, cytotoxicity evolution of DEP degradation intermediates is detected. The relationship between molar ratio ([H₂O₂]/[DEP] or [TiO₂]/[DEP]) and degradation kinetic constant (K) is also studied. And, the cytotoxicity tests of DEP and its degradation intermediates in UV/H₂O₂ and UV/TiO₂ treatments are researched. The DEP removal efficiency of UV/H₂O₂ treatment is higher than UV/TiO₂ treatment. The DEP degradation fitted a pseudo-first-order kinetic pattern under experimental conditions. The K linearly related with molar ratio in UV/H₂O₂ treatment while nature exponential relationship is observed in the case of UV/TiO₂. However, K fitted corresponding trends better in H₂O₂ treatment than in TiO₂ treatment. The Cl⁻ is in favor of the DEP degradation in UV/H₂O₂ treatment; in contrast, it is disadvantageous to the DEP degradation in UV/TiO₂ treatment. Other anions are all disadvantageous to the DEP degradation in two treatments. Fe³⁺ promotes the degradation rates significantly. And, all other cations in question inhibit the degradation of DEP. HA hinders DEP degradation in two treatments. The intermediates of DEP degradation in UV/TiO₂ treatment are less toxic to biological cell than that in UV/H₂O₂ treatment.

Nanoscale zerovalent iron (nZVI)-mediated degradation of 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT) was investigated in a spiked soil under different conditions (iron sources, iron dosage, soil moisture, temperature, and soil types) and DDT-contaminated field. The degradation efficiency of p,p′-DDT by nZVI and nZVI coated with sodium oleate (SO-nZVI) was much higher than that by nZVI coated with polyimide (PI-nZVI). The rapid degradation of p,p′-DDT by nZVI only occurred in flooded soil. The degradation half-life of p,p′-DDT decreased significantly from 58.3 to 27.6 h with nZVI dosage from 0.5 to 2.0 % and from 46.5 to 32.0 h with temperature from 15 to 35 °C. The degradation efficiency of p,p′-DDT by nZVI differed in Jinhua (JH), Jiaxing (JX), Xiaoshan (XS), Huajiachi (HJC), and Heilongjiang (HLJ) soils. A good correlation was found between the degradation half-life of p,p′-DDT and multiple soil properties. The probable nZVI-mediated degradation pathway of p,p′-DDT in soil was proposed as DDT → DDD/DDE → DDNS → DDOH based on the metabolites identified by GC-MS. The in situ degradation efficiency of residual DDTs in a contaminated field was profoundly enhanced by the addition of nZVI as compared to the control. It is concluded that nZVI might be an efficient agent for the remediation of DDT-contaminated soil under anaerobic environment.

This study explored the association between particulate matter with an aerodynamic diameter of less than 10 μm (PM₁₀) and the cause-specific respiratory mortality. We used the ordinary kriging method to estimate the spatial characteristics of ambient PM₁₀ at 1-km × 1-km resolution across Beijing during 2008–2009 and subsequently fit the exposure-response relationship between the estimated PM₁₀ and the mortality due to total respiratory disease, chronic lower respiratory disease, chronic obstructive pulmonary disease (COPD), and pneumonia at the street or township area levels using the generalized additive mixed model (GAMM). We also examined the effects of age, gender, and season in the stratified analysis. The effects of ambient PM₁₀ on the cause-specific respiratory mortality were the strongest at lag0-5 except for pneumonia, and an inter-quantile range increase in PM₁₀ was associated with an 8.04 % (95 % CI 4.00, 12.63) increase in mortality for total respiratory disease, a 6.63 % (95 % CI 1.65, 11.86) increase for chronic lower respiratory disease, and a 5.68 % (95 % CI 0.54, 11.09) increase for COPD, respectively. Higher risks due to the PM₁₀ exposure were observed for females and elderly individuals. Seasonal stratification analysis showed that the effects of PM₁₀ on mortality due to pneumonia were stronger during spring and autumn. While for COPD, the effect of PM₁₀ in winter was statistically significant (15.54 %, 95 % CI 5.64, 26.35) and the greatest among the seasons. The GAMM model evaluated stronger associations between concentration of PM₁₀. There were significant associations between PM₁₀ and mortality due to respiratory disease at the street or township area levels. The GAMM model using high-resolution PM₁₀ could better capture the association between PM₁₀ and respiratory mortality. Gender, age, and season also acted as effect modifiers for the relationship between PM₁₀ and respiratory mortality.

Coal production negatively affects the environment by the emission of polycyclic aromatic hydrocarbons (PAHs). Two soils (KOK and KB) from a coking plant area was investigated and their total PAH concentration was 40 and 17 mg/kg for the sum (∑) 16 US EPA PAHs, respectively. A third soil was sampled from a bitumen plant area and was characterized by 9 mg/kg ∑16 US EPA PAHs. To reduce the freely dissolved concentration (Cfᵣₑₑ) of the PAHs in the soil pore water, active carbon (AC) and two biochars pyrolysed from wheat straw (biochar-S) and willow (biochar-W) were added to the soils at 0.5–5 % (w/w), each. The AC performed best and reduced the Cfᵣₑₑ by 51–98 % already at the lowest dose. The biochars needed doses up to 2.5 % to significantly reduce the Cfᵣₑₑ by 44–86 % in the biochar-S and by 37–68 % in the biochar-W amended soils. The high black carbon (BC) content of up to 2.3 % in the Silesian soils competed with the sorption sites of the carbon amendments and the performance of the remediation was a consequence of the contaminant’s source and the distribution between the BC and the AC/biochars. In contrast, the carbon amendment could best reduce the Cfᵣₑₑ in the Lublin soil where the BC content was normal (0.05 %). It is therefore crucial to know the contaminant’s source and history of a sample/site to choose the appropriate carbon amendment not only for remediation success but also for economic reasons.