Estimating the atmospheric concentrations of PM₁₀-bounded selected metals in urban air is crucial for evaluating adverse health impacts. In the current study, a combination of measurements and multivariate statistical tools was used to investigate the influence of anthropogenic activities on variations in the contents of 18 metals (i.e., Al, Sc, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Cd, Sb, Ba, La, Ce and Pb) in ambient air. The concentrations of PM₁₀-bounded metals were measured simultaneously at eight air quality observatory sites during a half-year period at heavily trafficked roads and in urban residential zones in Bangkok, Thailand. Although the daily average concentrations of Al, V, Cr, Mn and Fe were almost equivalent to those of other urban cities around the world, the contents of the majority of the selected metals were much lower than the existing ambient air quality guidelines and standard limit values. The sequence of average values of selected metals followed the order of Al > Fe > Zn > Cu > Pb > Mn > Ba > V > Sb > Ni > As > Cr > Cd > Se > Ce > La > Co > Sc. The probability distribution function (PDF) plots showed sharp symmetrical bell-shaped curves in V and Cr, indicating that crustal emissions are the predominant sources of these two elements in PM₁₀. The comparatively low coefficients of divergence (COD) that were found in the majority of samples highlight that site-specific effects are of minor importance. A principal component analysis (PCA) revealed that 37.74, 13.51 and 11.32 % of the total variances represent crustal emissions, vehicular exhausts and the wear and tear of brakes and tires, respectively.

This study describes a gas chromatography-mass spectrometry analytical method for the analysis of cytostatic cyclophosphamide (CP), ifosfamide (IF) and their selected metabolites/transformation products (TPs): carboxy-cyclophosphamide (carboxy-CP), keto-cyclophosphamide (keto-CP) and 3-dechloroethyl-ifosfamide/N-dechloroethyl-cyclophosphamide (N-decl-CP) in wastewater (WW). Keto-cyclophosphamide, CP and IF were extracted with Oasis HLB and N-decl-CP and carboxy-CP with Isolute ENV+ cartridges. Analyte derivatization was performed by silylation (metabolites/TPs) and acetylation (CP and IF). The recoveries and LOQs of the developed method were 58, 87 and 103 % and 77.7, 43.7 and 6.7 ng L⁻¹ for carboxy-CP, keto-CP and N-decl-CP, respectively. After validation, the analytical method was applied to hospital WW and influent and effluent samples of a receiving WW treatment plant. In hospital WW, levels up to 2690, 47.0, 13,200, 2100 and 178 ng L⁻¹ were detected for CP, IF, carboxy-CP, N-decl-CP and keto-CP, respectively, while in influent and effluent samples concentrations were below LOQs. The formation of TPs during abiotic treatments was also studied. Liquid chromatography-high-resolution mass spectrometry was used to identify CP and IF TPs in ultrapure water, treated with UV and UV/H₂O₂. UV treatment produced four CP TPs and four IF TPs, while UV/H₂O₂ resulted in five CPs and four IF TPs. Besides already known TPs, three novel TPs (CP-TP138a, imino-ifosfamide and IF-TP138) have been tentatively identified. In hospital WW treated by UV/O₃/H₂O₂, none of the target metabolites/TPs resulted above LOQs.

Significant knowledge gaps exist regarding the fate and transport of persistent organic pollutants like dichlorodiphenyltrichloroethane (DDT) in tropical environments. In Brazil, indoor residual spraying with DDT to combat malaria and leishmaniasis began in the 1950s and was banned in 1998. Nonetheless, high concentrations of DDT and its metabolites were recently detected in human breast milk in the community of Lake Puruzinho in the Brazilian Amazon. In this work, we couple analysis of soils and sediments from 2005 to 2014 at Puruzinho with a novel dynamic floodplain model to investigate the movement and distribution of DDT and its transformation products (dichlorodiphenyldichloroethylene (DDE) and dichlorodiphenyldichloroethane (DDD)) and implications for human exposure. The model results are in good agreement with the accumulation pattern observed in the measurements, in which DDT, DDE, and DDD (collectively, DDX) accumulate primarily in upland soils and sediments. However, a significant increase was observed in DDX concentrations in soil samples from 2005 to 2014, coupled with a decrease of DDT/DDE ratios, which do not agree with model results assuming a post-ban regime. These observations strongly suggest recent use. We used the model to investigate possible re-emissions after the ban through two scenarios: one assuming DDT use for IRS and the other assuming use against termites and leishmaniasis. Median DDX concentrations and p,p′-DDT/p,p′-DDE ratios from both of these scenarios agreed with measurements in soils, suggesting that the soil parameterization in our model was appropriate. Measured DDX concentrations in sediments were between the two re-emission scenarios. Therefore, both soil and sediment comparisons suggest re-emissions indeed occurred between 2005 and 2014, but additional measurements would be needed to better understand the actual re-emission patterns. Monte Carlo analysis revealed model predictions for sediments were very sensitive to highly uncertain parameters associated with DDT degradation and partitioning. With this model as a tool for understanding inter-media cycling, additional research to refine these parameters would improve our understanding of DDX fate and transport in tropical sediments.

China has experienced rapid development in the past 30 years but, alongside and associated with this growth, increased levels of pollution too. However, despite the continued increase in emissions of haze-forming aerosols in the twenty-first century, the annual number of haze days in some megacities has not risen in tandem. Various mechanisms have been proposed for “city dimming”, but the cause of the hiatus remains unclear. We found that the number of haze days in Taiyuan experienced a sharp increase during 1980–1998, with a growth rate 51.6 days/10a, and then exhibited fluctuating variation around a stable high level from 1998 to 2014, while at the same time the average visibility during haze days started to decrease. We present a novel method to explain the long-term variation in the number of haze days via a temporal-piecewise function of human activities and atmospheric cleaning processes: the number of haze days increases with the level of human activity before reaching the upper limit and then remains at a high level due to the restriction of a relatively stable number of strong cleaning days.

Crack cocaine is a very toxic product derived from cocaine. The aim of this study was to evaluate genetic damage in multiple organs of rats following acute exposure to crack cocaine. A total of 20 Wistar rats were distributed into four groups (n = 5), as follows: 0, 4.5, 9, and 18 mg/kg body weight (b.w.) of crack cocaine administered by intraperitoneal route (i.p.). All animals were killed 24 h after intraperitoneal (i.p.) injection. The results showed that crack cocaine increased the number of micronucleated cells in bone marrow cells exposed to 18 mg/kg crack cocaine (p < 0.05). Peripheral blood and liver cells presented genetic damage as depicted by single cell gel (comet) assay at 9 and 18 mg/kg doses (p < 0.05). Immunohistochemistry data revealed significant increase in 8-hydroxy-20-deoxyguanosine (8-OHdG) immunoexpression in hepatocytes of animals exposed to crack cocaine at 9 and 18 mg/kg (p < 0.05) when compared with negative controls. Taken together, our results demonstrate that crack cocaine is able to induce genomic damage in multiple organs of Wistar rats.

Pharmaceutical industries are amongst the foremost contributor to industrial waste. Ecological well-being is endangered owing to its facile discharge. In the present study, heavy metals and organic contaminants in waste water were characterized using atomic absorption spectrophotometer and GC-MS, respectively. Mutagenicity and genotoxic potential of pharmaceutical waste water were investigated through bacterial reverse mutation assay and in vitro comet assay, respectively. Ames test and comet assay of first sample were carried out at concentrations of 100, 50, 25, 12.5, 6.25 % v/v effluent with distilled water. Chromium (Cr), lead (Pb), arsenic (As), and cadmium (Cd) were found in high concentrations as compared to WHO- and EPA-recommended maximum limits. Arsenic was found to be the most abundant metal and its maximum concentration was 0.8 mg.L⁻¹. GC-MS revealed the presence of lignocaine, digitoxin, trimethoprim, caffeine, and vitamin E in waste water. Dose-dependent decrease in mutagenic index was observed in both strains. Substantial increase in mutagenicity was observed for TA-100, when assay was done by incorporating an enzyme activation system, whereas a slight increase was detected for TA-102. In vitro comet assay of waste water exhibited decrease in damage index and percentage fragmentation with the increase in dilution of waste water. Tail length also decreased with an increase in the dilution factor of waste water. These findings suggest that pharmaceutical waste water being a mix of different heavy metals and organic contaminants may have a potent mutagenic and genotoxic effect on exposed living organisms.

Bauxite residue often has chemical and physical limitations to support plant growth, and improving its matrix properties is crucial to support sustainable vegetation in the long term. Spontaneous vegetation colonization on deposits in Central China, over a period of 20 years, has revealed that natural weathering processes may convert bauxite residue to a soil-like medium. Residue samples from different stacking ages were collected to determine the effect of natural processes on matrix properties over time. It was demonstrated that natural processes decreased pH (10.98 to 9.45), electrical conductivity (EC) (3.73 to 0.36 mS/cm), and exchangeable sodium percentage (ESP) (72.51 to 28.99 %), while increasing bulk density (1.91 to 1.39 g/cm³), improving the mean weight diameter (MWD) of water-stable aggregates (0.24 to 0.52 mm), and the proportion of >0.25-mm water-stable aggregates (19.91 to 50.73 %). The accumulation of organic carbon and the reduction of ESP and exchangeable Na had positive effects on soil aggregate formation, while exchangeable Ca and Mg were significantly beneficial to aggregation of water-stable aggregates. Climate, stacking time, and biological factors appear to improve the structure of bauxite residue. Our findings demonstrate soil genesis occurring following natural weathering processes of bauxite residues over time.

Vermicomposting is a low-cost, eco-efficient process to deal with organic wastes. Mixtures of swine manure (SM), cow dung (CD), and animal wastewater treatment plant sludge (S) were applied as feeds, and Eisenia fetida was employed in this study to investigate the vermicomposting efficiency based on their several growth stages. The hatching test resulted in a 100 % hatching rate in S₆₀SM₄₀ (60 % S + 40 % SM) mixture, while 4.40 hatchlings per cocoon were observed. The growth of infancy performed best in 0–20 % CD mixtures (0.05 ± 0.002 g), followed by in SM + CD (0.04 ± 0.003 g). The highest growth rate of young and adult E. fetida was noticed in CD + S mixtures (11.14 ± 0.01 and 6.00 ± 0.02 mg/d/worm, respectively), while the higher cocoon production of adults was noticed in S + SM mixtures especially in S₄₀SM₆₀ (537 ± 5 worms). Moreover, the conversion of solids; the modified pH value; the reduction in total organic carbon (TOC); total Kjeldahl nitrogen (TKN), NH₄-N, NO₃-N, and C:N ratio; and the rich in total available phosphorus (TAP) and total potassium (TK) content by young and adult E. fetida were related to the growth of worms. Such work would benefit understanding and to increase the efficiency of vermicompost processing of different wastes.

Recent experiments showed that 5-fluorouracil (5FU), cisplatin (CDDP), etoposide (ET), and imatinib mesylate (IM), which are currently among the most widely used anticancer drugs, cause damage of the genetic material in higher plants. The aim of the present study was to determine whether mixtures of these drugs cause synergistic or antagonistic effects which may have an impact on their environmental safety. Therefore, the effects of binary mixtures of these anticancer drugs on the induction of micronuclei (MN) which reflect structural and numerical chromosomal aberrations were assessed in Tradescantia tetrads. Synergistic/antagonistic effects were determined by comparison with single exposures that would be equally effective in a reference model of independent action. This comparison was performed at two distinct effect sizes. We found clear evidence for synergisms in combination experiments with IM and antagonism in a high-dose experiment with ET and 5FU. Our findings indicate that IM increases the genotoxic effects of other anticancer drugs. The maximal effects which we found were in the range between 19 and 38 % in the excess of effect sizes predicted under independent action. These effects may have an impact on the overall genotoxic activities of untreated hospital waste waters but not on the environment in general as the predicted environmental concentrations of the studied drugs are several orders of magnitude lower as the levels which are required to cause induction of MN in higher plants.