Nanomaterial (NM) release into wastewater treatment plants (WWTPs) is inevitable due to increased production and application throughout past decades and in the future. Concern arose about environmental risks and impact on activated sludge. Environmental risk assessment (ERA) for NMs according to established guidelines is considered not suitable, because NMs exhibit unique characteristics. For hazard identification on activated sludge, standard test organisms for aquatic toxicity testing are not meaningful. In this study, we developed an acute toxicity test for ciliates (Paramecium tetraurelia) as representatives of the important functional group of microbial predators and filter feeders. We chose silver nanoparticles (nAg) exemplarily for ion releasing nanoparticles and regarded toxicity by ions as well. Our results indicate that ions are more toxic (EC₅₀0.73 mg/L) than nanoparticles themselves (EC₅₀2.15 mg/L). However, nAg must be considered as a source of ions and requires size, surface coating, and compartment-specific ERA. We strived to develop such ERA based on our results, modeled environmental concentration data from literature, and surface area concentrations. Results indicated a probable risk toward activated sludge. This likely has effects on effluent water quality. We conclude that carefully modeled environmental concentrations are vital for more exact ERA for nAg and other NMs.

This study aimed to assess the association between exposure to air pollution and unintentional injury deaths in South Korea. Data regarding all unintentional injury deaths (17,566) in seven metropolitan cities from 2002 to 2008 were collected. Using a time-stratified case-crossover study, conditional logistic regression and subgroup analyses were performed after stratification by age, gender, and season. To evaluate immediate and delayed effects of air pollutants, we used both single lag and distributed lag models. The risk was expressed as an odds ratio (OR) per one interquartile range (IQR) of each air pollutant. During the study period, the median (IQR) levels of air pollutants were 0.005 (0.004–0.007) ppm for sulfur dioxide (SO₂), 0.02 (0.02–0.03) ppm for nitrogen dioxide (NO₂), 0.03 (0.02–0.04) ppm for ozone (O₃), 48.3 (34.9–67.0) μg/m³for particulate matter ≤10 μm in aerodynamic diameter (PM₁₀), and 0.36 (0.1–0.6) ppm for carbon monoxide (CO). All air pollutants, with the exception of PM₁₀and O₃, were significantly associated with an increased risk of unintentional injury deaths; the maximum risk was observed in the distributed lag 1 model for SO₂(OR, 1.119; 95 % confidence interval, 1.022–1.226), NO₂(1.208; 1.043–1.400), and CO (1.012; 1.000–1.024). After stratification of the subjects by age, SO₂, NO₂, and CO were significantly associated with increased risk of unintentional injury deaths among subjects aged 60 years or older in the distributed lag 1 model, while O₃and PM₁₀were associated with increased risk among subjects aged 40 to 59 years. However, in subjects younger than 40 years of age, we found no significant associations for any of the air pollutants. Our study suggested evidence for a short-term association between air pollutants and unintentional injury deaths, even at low pollutants levels.

In the current batch study, we investigated the effect of solution properties, competing ligands (phosphate (P(V)) and sulfate), and complexing metal (calcium (Ca²⁺)) on tetracycline (TTC) and oxytetracycline (OTC) sorption by Al-based drinking water treatment residuals (Al-WTR). The sorption behavior for both TTC and OTC on Al-WTR was pH dependent. The sorption in absence of competing ligands and complexing metal increased with increasing pH up to circum-neutral pH and then decreased at higher pH. The presence of P(V) when added simultaneously had a significant negative effect (p < 0.001) on the sorption of TTC and OTC adsorbed by Al-WTR at higher TTC/OTC:P ratios. However, when P(V) was added after the equilibration of TTC and OTC by Al-WTR, the effect was minimal and insignificant (p > 0.1). The presence of sulfate had a minimal/negligible effect on the sorption of TCs by Al-WTR. A significant negative effect (p < 0.001) on the adsorption of TCs by Al-WTR was observed in the pH range below 5 and at higher TCs:Ca²⁺ratios, probably due to TCs-Ca²⁺complex formation. Fourier transform infrared (FTIR) analysis indicated the possibility of inner-sphere-type bonding by the functional groups of OTC/TTC on Al-WTR surface. Results from the batch sorption study indicate high affinity of Al-WTR for TCs in the pH range 4–8 (majorly encountered pH in the environment) in the presence of competing ligands and complexing metal.

The sources of the spill and the contaminated soils of an aged oil spill contaminated site with unknown mixed pollutants were investigated by using a set of developed forensic chemical procedures which include analysis of oil products, site investigation, gas chromatography/mass spectrometry (GC/MS) screening, biomarker identification, and finally, the confirmation of pollutants. Adamantanes (17 compounds), 10 bicyclic sesquiterpanes, 6 newly detected compounds, 16 polycyclic aromatic hydrocarbons, and 10 alkylated naphthalenes compounds in several gasoline, diesel oil samples, and contaminated soil samples were examined and quantified. GC/MS method, retention indices, relative response factors, and diagnostic ratio were used to identify and quantify pollutant compounds. The study revealed the key factors for distinguishing among gasoline and diesel oil products in the market, created a new set of retention indices for 10 bicyclic sesquiterpane compounds, and discovered 6 quantifiable compounds in analysis of fresh oil products. The suggested diagnostic ratios for BSs and the new compounds in the analysis of the biomarker show the differences among diesel products, link between the source of pollutants with contaminated soil, and the recognition of the signs of an aged spill, and the indications of weathering effects.

The hydroponic experiment was carried out to investigate the Cd subcellular distribution and chemical forms in roots and shoots among four soybean seedling cultivars with two Cd treatments. HX3 and GC8, two tolerant and low-grain-Cd-accumulating cultivars, had the lowest Cd concentration in roots and high Cd concentration in shoots, while BX10 and ZH24, two sensitive and high-grain-Cd-accumulating cultivars, had the highest Cd concentration in roots and the lowest Cd concentration in shoots at young seedling stage. Furthermore, the sequence of Cd subcellular distribution in roots at two Cd levels was cell wall (53.4–75.5 %) > soluble fraction (15.8–40.4 %) > organelle fraction (2.0–14.7 %), but in shoots, was soluble fraction (39.3–74.8 %) > cell wall (16.0–52.0 %) > organelle (4.8–19.5 %). BX10 and ZH24 had higher Cd concentration in all subcellular fractions in roots, but HX3 and GC8 had higher Cd concentration of soluble fraction in shoots. The sequence of Cd chemical forms in roots was FNₐcₗ (64.1–79.5 %) > FHAC (3.4–21.5 %) > Fd₋H₂O (3.6–13.0 %) > Fₑₜₕₐₙₒₗ (1.4–21.8) > FHCₗ (0.3–1.6 %) > Fₒₜₕₑᵣ (0.2–1.4 %) at two Cd levels but, in shoots, was FNₐcₗ (19.7–51.4 %) ≥ FHAC (10.2–31.4 %) ≥ Fd₋H₂O (8.8–28.2 %) ≥ Fₑₜₕₐₙₒₗ (8.9–38.6 %) > FHCₗ (0.2–9.6 %) > Fₒₜₕₑᵣ (2.5–11.2 %). BX10 and ZH24 had higher Cd concentrations in each extracted solutions from roots, but from shoots for GC8 and HX3. Taken together, the results uncover that root cell walls and leaf vacuoles might play important roles in Cd detoxification and limiting the symplastic movement of Cd.

Ultraviolet (UV) filters are widely used in the formulation of personal care products (PCPs) to prevent damage to the skin, lips, and hair caused by excessive UV radiation. Therefore, large amounts of these substances are released daily into the aquatic environment through either recreational activities or the release of domestic sewage. The concern regarding the presence of such substances in the environment and the exposure of aquatic organisms is based on their potential for bioaccumulation and their potential as endocrine disruptors. Although there are several reports regarding the occurrence and fate of UV filters in the aquatic environment, these compounds are still overlooked in tropical areas. In this study, we investigated the occurrence of the organic UV filters benzophenone-3 (BP-3), ethylhexyl salicylate (ES), ethylhexyl methoxycinnamate (EHMC), and octocrylene (OC) in six water treatment plants in various cities in Southeast Brazil over a period of 6 months to 1 year. All of the UV filters studied were detected at some time during the sampling period; however, only EHMC and BP-3 were found in quantifiable concentrations, ranging from 55 to 101 and 18 to 115 ng L⁻¹, respectively. Seasonal variation of BP-3 was most clearly noticed in the water treatment plant in Araraquara, São Paulo, where sampling was performed for 12 months. BP-3 was not quantifiable in winter but was quantifiable in summer. The levels of BP-3 were in the same range in raw, treated and chlorinated water, indicating that the compound was not removed by the water treatment process.

Arsenic is a well-known toxic substance on the living organisms. However, limited efforts have been made to study its DNA methylation, genomic instability, and long terminal repeat (LTR) retrotransposon polymorphism causing properties in different crops. In the present study, effects of As₂O₃ (arsenic trioxide) on LTR retrotransposon polymorphism and DNA methylation as well as DNA damage in Zea mays seedlings were investigated. The results showed that all of arsenic doses caused a decreasing genomic template stability (GTS) and an increasing Random Amplified Polymorphic DNAs (RAPDs) profile changes (DNA damage). In addition, increasing DNA methylation and LTR retrotransposon polymorphism characterized a model to explain the epigenetically changes in the gene expression were also found. The results of this experiment have clearly shown that arsenic has epigenetic effect as well as its genotoxic effect. Especially, the increasing of polymorphism of some LTR retrotransposon under arsenic stress may be a part of the defense system against the stress.

Glutathione (GSH) plays crucial roles in antioxidant defense and detoxification metabolism of microcystin-LR (MC-LR). However, the detoxification process of MC-LR in mammals remains largely unknown. This paper, for the first time, quantitatively analyzes MC-LR and its GSH pathway metabolites (MC-LR-GSH and MC-LR-Cys) in the liver of Sprague–Dawley (SD) rat after MC-LR exposure. Rats received intraperitoneal (i.p.) injection of 0.25 and 0.5 lethal dose 50 (LD₅₀) of MC-LR with or without pretreatment of buthionine-(S,R)-sulfoximine (BSO), an inhibitor of GSH synthesis. The contents of MC-LR-GSH were relatively low during the experiment; however, the ratio of MC-LR-Cys to MC-LR reached as high as 6.65 in 0.5 LD₅₀ group. These results demonstrated that MC-LR-GSH could be converted to MC-LR-Cys efficiently, and this metabolic rule was in agreement with the data of aquatic animals previously reported. MC-LR contents were much higher in BSO + MC-LR-treated groups than in the single MC-LR-treated groups. Moreover, the ratio of MC-LR-Cys to MC-LR decreased significantly after BSO pretreatment, suggesting that the depletion of GSH induced by BSO reduced the detoxification of MCs. Moreover, MC-LR remarkably induced liver damage, and the effects were more pronounced in BSO pretreatment groups. In conclusion, this study verifies the role of GSH in the detoxification of MC-LR and furthers our understanding of the biochemical mechanism for SD rats to counteract toxic cyanobacteria.

Veterinary antibiotics introduced into soil environment may change the composition and functioning of soil microbial communities and promote the spreading of antibiotic resistance. Actual risks depend on the antibiotic’s bioaccessibility and sequestration in soils, which may vary with contact time and soil properties. We elucidated changes in the horsebean plant’s bioaccessible oxytetracycline with increasing contact time in three different soils (cinnamon, red, and brown soil) and observed discrepancy in oxytetracycline dissipation using sequential extractions with H₂O-, 0.01 M CaCl₂-, and Mcllvaine- in the same three soils. The results showed lower quantities of oxytetracycline with increasing contact time over 20 days than the level in freshly contaminated soils but hugely discrepant quantities among the three tested soils. In addition, aging largely reduced dissipation of H₂O-, 0.01 M CaCl₂-, and Mcllvaine- extracted oxytetracycline in soils before planting. However, bioturbation helped increase the H₂O-, CaCl₂-, and Mcllvaine- extracted oxytetracyline from cinnamon and brown soils with aging. Lastly, correlation analysis indicated that bioaccessibility of oxytetracycline significantly correlates with the total of H₂O-, CaCl₂-, and Mcllvaine- extracted oxytetracycline (0.676**, p < 0.01) in soils, especially the H₂O- (0.789**, p < 0.01) and Mcllvaine- (0.686**, p < 0.01) extracted oxytetracycline with aging. Overall, this study provides some basic understanding of the aging effect on sequestration and bioaccessibility of veterinary antibiotics in soils.

Reliable empirical models describing arsenic (As) transfer in soil-plant systems are needed to estimate the human As burden from dietary intake. A greenhouse experiment was conducted in parallel with a field trial located at three sites through China to develop and validate soil-plant transfer models to predict As concentrations in carrot (Daucus carota L.). Stepwise multiple linear regression relationships were based on soil properties and the pseudo total (aqua regia) or available (0.5 M NaHCO₃) soil As fractions. Carrot As contents were best predicted by the pseudo total soil As concentrations in combination with soil pH and Fe oxide, with the percentage of variation explained being up to 70 %. The constructed prediction model was further validated and improved to avoid overprotection using data from the field trial. The final obtained model is of great practical relevance to the prediction of As uptake under field conditions.