Environmental implications of combustion of rice husk at high temperatures and for an extended period for energy generation.

The most common alternative for the management and valorization of rice processing waste is the combustion of rice husk (RH) for energy generation. The environmental risk assessment of the ash generated during the combustion of the RH to obtain energy has remained understudied. Disposal of rice husk ash (RHA) on agricultural land is the most common outcome, which could pose a risk to both natural ecosystems and human health. The objective of this study was to characterize the physicochemical composition and the phytotoxicity, cytotoxicity, and genotoxicity of RHA obtained from three distinct combustion processes. The evaluation processes were 800-900 °C in up to 5 min (I), 800-900 °C in 15-20 min (II), and 600-700 °C in 15-20 min (III). Furthermore, the content, pH, and concentrations of Al, Cd, Cu, Fe, Mg, Mn, Mo, Na, Ni, and Ti present in the ashes were determined. The germination index for two vegetable seeds was subsequently evaluated. By measuring the mitotic index and frequency of chromosomal aberrations, the cytotoxicity and genotoxicity were determined. It was observed that RHA produced by combustion of RH at higher combustion temperatures for an extended period exhibited different physicochemical properties, in addition to higher levels of phytotoxicity, cytotoxicity, and genotoxicity.

Genetic damage in coal and uranium miners.

Mining has a direct impact on the environment and on the health of miners and is considered one of the most hazardous occupations worldwide. Miners are exposed to several occupational health risks, including genotoxic substances, which may cause adverse health effects, such as cancer. This review summarizes the relation between DNA damage and mining activities, focusing on coal and uranium miners. The search was performed using electronic databases, including original surveys reporting genetic damage in miners. Additionally, a temporal bibliometric analysis was performed using an electronic database to create a map of cooccurrence terms. The majority of studies were performed with regard to occupational exposure to coal, whereas genetic damage was assessed mainly through chromosomal aberrations (CAs), micronuclei (MNs) and comet assays. The bibliometric analysis demonstrated associations of coal exposure with silicosis and pneumoconiosis, uranium miners with lung cancer and tumors and some associated factors, such as age, smoking, working time and exposure to radiation. Significantly higher DNA damage in miners compared to nonexposed groups was observed in most of the studies. The timeline reveals that classic biomarkers (comet assay, micronucleus test and chromosomal aberrations) are still important tools to assess genotoxic/mutagenic damage in occupationally exposed miners; however, newer studies concerning genetic polymorphisms and epigenetic changes in miners are being conducted. A major challenge is to investigate further associations between miners and DNA damage and to encourage further studies with miners of other types of ores.

Antifouling paint particles in soils: toxic impact that goes beyond the aquatic environment.

Antifouling paint particles (APPs) originate from vessel maintenance and cleaning activities and their potentially toxic components are found at high concentrations in nearby soils, yet no studies have investigated their toxicity to soil organisms. We investigated the effects of exposure to soils containing APPs on the mortality, biomass, and reproductive performance of the earthworm Eisenia andrei. Earthworms were exposed to contaminated soil from a boatyard and non-contaminated soils treated with different concentrations of APPs (0.01, 0.14 and 1.50%, w/w) for 56 days. An ecological risk assessment using a Hazard Quotient (HQ) was also carried out. Exposure to contaminated soils reduced worm survival, biomass, and reproductive performance and these effects were concentration-dependent. The HQ was high in soil samples with APPs in both acute and chronic tests, and copper contributed the most to the HQ. Copper, zinc, and lead had the highest concentrations and exceeded the Brazilian legal limits. A principal component analysis (PCA) was performed and showed that biomass and number of juveniles parameters was associated with the metals Cu, Sn and Zn, while the mortality parameter had no association with any analyzed metal. These findings highlighted that the synergistic effects of compounds present in the APPs, such as the booster biocides DCOIT, and metal mixtures should not be overlooked. We conclude that soils contaminated with APPs are toxic to earthworms. This reveals that the ecological impact of APPs goes beyond effects on aquatic environments, compromising key organisms of edaphic ecological processes.

Exposure to few-layer graphene through diet induces oxidative stress and histological changes in the marine shrimp Litopenaeus vannamei.

The production and use of graphene-based nanomaterials is rapidly increasing. However, few data are available regarding the toxicity of these nanomaterials in aquatic organisms. In the present study, the toxicity of few-layer graphene (FLG) (obtained by chemical exfoliation) was evaluated in different tissues of the shrimp Litopenaeus vannamei following exposure to FLG through a diet for four weeks. Transmission electron microscopy and dynamic light scattering measurements showed a distribution of lateral sheet sizes between 100 and 2000 nm with the average length and width of 800 and 400 nm, respectively. Oxidative stress parameters were analyzed, indicating that FLG exposure led to an increase in the concentration of reactive oxygen species, modulated the activity of antioxidant enzymes such as glutamate cysteine ligase and glutathione-S-transferase, and reduced glutathione levels and total antioxidant capacity. However, the observed modulations were not sufficient to avoid lipid and DNA damage in both gill and hepatopancreas tissues. Furthermore, graphene exposure resulted in morphological changes in hepatopancreas tissues. These results demonstrate that exposure to FLG through the diet induces alterations in the redox state of cells, leading to a subsequent oxidative stress situation. It is therefore clear that nanomaterials presenting these physico-chemical characteristics may be harmful to aquatic biota.

Anti-inflammatory Effect and Toxicology Analysis of Oral Delivery Quercetin Nanosized Emulsion in Rats.

PURPOSE: This study evaluates the advantage of the quercetin encapsulation in nanosized emulsion (QU-NE) administered orally in rats in order to demonstrate its anti-oedematous and antioxidant effects as well as its toxicity. METHODS: The nanocarriers were prepared using the hot solvent diffusion with the phase inversion temperature methods. The nanocarriers physicochemical properties were then investigated. The anti-edematous activity was tested using paw edema in rats. In addition, NF-kB expression in subcutaneous tissue of the paws was accessed by immunohistochemistry while the lipid peroxidation was analyzed in the liver by malondialdehyde reaction with thiobarbituric acid. Hematological, renal and hepatic toxicity as well as the genetic damage were also evaluated. RESULTS: The results demonstrated that QU-NE exhibited pronounced anti-oedematous property comparable to drug diclofenac. This effect was associated with NF-κB pathway inhibition. The lipid peroxidation was also only reduced in rats treated with QU-NE. Besides this, no genetic damage, hematological, renal or hepatic toxicities were observed after administration of QU-NE. CONCLUSIONS: These results suggest that quercetin nanosized emulsion exhibits anti-oedematous and antioxidant properties and does not demonstrate toxic effects. This indicates that it has a potential application in the treatment of inflammatory diseases.

Geno- and cyto-toxicity in free-living rodent Mus spretus exposed to simulated onshore oil spill.

This study investigated geno- and cyto-toxic damage in the free-living rodent, Mus spretus after exposure to a simulated spill of crude oil on soil. The results revealed increased mutagenicity and cytotoxicity in bone marrow cells and increased DNA damage in blood cells. Exposure to crude oil increased sperm abnormalities, with lasso-like folds being the most common. These results point to the value of this rodent in serving as a sentinel species for the monitoring and prediction of environmental hazards.