Increased micronucleus frequencies in reticulocytes of children exposed to industrial pollution: oxidative stress and the OGG1 S326C polymorphism

HBM4EU Chromates Study-Genotoxicity and Oxidative Stress Biomarkers in Workers Exposed to Hexavalent Chromium

A study was conducted within the European Human Biomonitoring Initiative (HBM4EU) to characterize occupational exposure to Cr(VI). Herein we present the results of biomarkers of genotoxicity and oxidative stress, including micronucleus analysis in lymphocytes and reticulocytes, the comet assay in whole blood, and malondialdehyde and 8-oxo-2′-deoxyguanosine in urine. Workers from several Cr(VI)-related industrial activities and controls from industrial (within company) and non-industrial (outwith company) environments were included. The significantly increased genotoxicity (p = 0.03 for MN in lymphocytes and reticulocytes; p < 0.001 for comet assay data) and oxidative stress levels (p = 0.007 and p < 0.001 for MDA and 8-OHdG levels in pre-shift urine samples, respectively) that were detected in the exposed workers over the outwith company controls suggest that Cr(VI) exposure might still represent a health risk, particularly, for chrome painters and electrolytic bath platers, despite the low Cr exposure. The within-company controls displayed DNA and chromosomal damage levels that were comparable to those of the exposed group, highlighting the relevance of considering all industry workers as potentially exposed. The use of effect biomarkers proved their capacity to detect the early biological effects from low Cr(VI) exposure, and to contribute to identifying subgroups that are at higher risk. Overall, this study reinforces the need for further re-evaluation of the occupational exposure limit and better application of protection measures. However, it also raised some additional questions and unexplained inconsistencies that need follow-up studies to be clarified.

Mixture of Toxic Metals and Volatile Organic Compounds in a River Induces Cytotoxicity

Pollution of aquatic ecosystems due to toxic mixtures is a worldwide problem associated with the increase of wastewater discharges that causes problems to human health and biodiversity. This study aims to evaluate the cytotoxic potential of water from the Atoyac River. Meristems of Allium cepa L. were exposed to water samples from the Atoyac River with different concentrations for 120 hours. Pearson correlation was used to investigate the relationship between contaminants and cytotoxicity. The results corroborated the cytotoxic effect of the mixture of agents such as toxic metals and volatile organic compounds found in all river sampling sites. The Allium cepa test showed decreased mitotic alterations in prophase and metaphase indices. There was a strong negative association between the concentration of toxic metals and volatile organic compounds and the cytotoxic effect. The observations of cytotoxic effects show that the contaminant mixture contains aneugenic agents which prevent the synthesis and fixation of fibers of the mitotic spindle to the kinetochore, which prevents the displacement of the chromosomes. This study shows the need to study the effects at the cellular and molecular level in heavily polluted rivers to prevent negative effects on exposed ecosystems and populations.

The Impact of Urbanization on Water Quality: Case Study on the Alto Atoyac Basin in Puebla, Mexico

Population growth, poorly planned industrial development and uncontrolled production processes have left a significant footprint of environmental deterioration in the Alto Atoyac watershed. In this study, we propose using the integrated pollution index (PI) to characterize the temporary variations in surface water quality during the rapid urbanization process in the municipalities of San Martín Texmelucán (SMT) and Tepetitla de Lardizabal (TL), in the states of Puebla and Tlaxcala, between 1985 and 2020. We assessed the correlation between the population growth rate and the water quality parameters according to the Water Quality Index (ICA). The contribution of each polluting substance to the PI was determined. The industry database was created and the increase in population and industry, and their densities, were estimated. The results indicated that the temporal pattern of surface water quality is determined by the level of urbanization. The water integrated pollution index (WPI) increased with the passage of time in all the localities: SLG 0.0 to 25.0; SMTL 25.0 to 29.0; SRT 4.0 to 29.0; VA 6.0 to 30.0; T 3.5 to 24.0 and SMA 4.0 to 27.0 from 2010 to 2020, respectively. The correlation coefficients between the five parameters (BOD5, COD, CF, TU and TSS) in the six localities were positive with the population. The values that showed a higher correlation with the population were: SLG (FC 0.86), SMTL (BOD5 0.61, COD 0.89, TSS 0.64) and SRT (TU 0.83), corresponding to highly polluted localities, which generates complex and severe environmental implications due to the unsustainable management of water resources. Achieving the sustainability of water in the watershed is a challenge that should be shared between society and state. This type of research can be a useful tool in making environmental management decisions.

The catalytic and ROS-scavenging activities of green synthesized, antiferromagneticα-Fe2O3nanoparticle with a prismatic octahedron morphology from pomegranate rind extract

Phenolic compounds (like 4-nitrophenol) and dyes (like methyl orange) are common by-products discharged by many industries as wastes; they are toxic and may induce discomfort and irritation in humans when ingested. Most of these compounds can be made less toxic through catalytic degradation. Metal oxide nanoparticles are found to have high catalytic activity and can degrade toxic phenolic compounds and dyes. In the current study, pomegranate rind extract was used for the green synthesis of iron oxide nanoparticles that exhibited an octahedron morphology revealed by scanning electron microscopy analysis. Energy dispersive x-ray analysis showed 47.96% content of Fe (by weight); high resolution-transmission electron microscopy analysis confirmed that the nanoparticles had a particle size of 22.54 ± 4.13 nm. The particles were further characterized by x-ray diffraction, fourier transform-infrared spectroscopy, vibrating sample magnetometer, and thermogravimetric analysis. The nanoparticle proved to be efficient in reducing 4-nitrophenol and methyl orange. It was also found to be non-toxic towards murine macrophages, RAW 264.7 with good ROS-scavenging potential compared to control.

Focus on DNA Glycosylases-A Set of Tightly Regulated Enzymes with a High Potential as Anticancer Drug Targets

Cancer is the second leading cause of death with tens of millions of people diagnosed with cancer every year around the world. Most radio- and chemotherapies aim to eliminate cancer cells, notably by causing severe damage to the DNA. However, efficient repair of such damage represents a common mechanism of resistance to initially effective cytotoxic agents. Thus, development of new generation anticancer drugs that target DNA repair pathways, and more particularly the base excision repair (BER) pathway that is responsible for removal of damaged bases, is of growing interest. The BER pathway is initiated by a set of enzymes known as DNA glycosylases. Unlike several downstream BER enzymes, DNA glycosylases have so far received little attention and the development of specific inhibitors of these enzymes has been lagging. Yet, dysregulation of DNA glycosylases is also known to play a central role in numerous cancers and at different stages of the disease, and thus inhibiting DNA glycosylases is now considered a valid strategy to eliminate cancer cells. This review provides a detailed overview of the activities of DNA glycosylases in normal and cancer cells, their modes of regulation, and their potential as anticancer drug targets.

Micronuclei, reproduction and child health

The current review looks for relationships between results from biomarker studies with micronucleus and health effects related to reproduction and children. In adults, an age related increase in MN is well known as well as associations with environmental exposures especially air pollution from traffic and smoking. Literature searches in PubMED and SCOPUS were performed with the following keywords reproduction, children, micronuclei, health effects. In total 162 studies were identified with the keyword children. Concerning children and health and children and environmental exposures, the titles and abstracts of a total of 162 publications were screened for language, inclusion of data from children and selected according to a study selection chart. 9 studies were included for children and health, and 21 studies for children and environmental exposures, with 12 in buccal cells and 9 in lymphocytes. The publications were read and included in tables if data on controls was available. MN frequencies were collected for peripheral blood lymphocytes (PBLs), reticulocytes or buccal cells (BC) and reported as Mean ± SD or Median (IQR). The Mean frequency Ratio, MRi, corresponding to the MN mean for study persons divided by MN mean for control persons was stated as reported in the publication or calculated by us from the data in the publication, where possible. Our systematic analysis revealed a number of positive associations of MN frequencies as a marker of increased health risk in relation to reproduction as well as child health. The majority of studies reported with children concerns exposures of children as well as maternal exposures and newborn health with MN as a biomarker of exposure. Exposure monitoring by MN as biomarker is also reported in studies of school children however most often not related to health effects. The MRis are found in ranges from 1 to 5.5 most studies around 2. As far as MN frequencies in children and exposure are concerned, the MRis range from 0.9 to 5.5, with a range from 1.3-4.9 for lymphocytes and from 1.5 to 2.5 in buccal cells, except for two studies with no differences found between cases and controls. Only one study is available for MRi calculation in reticulocytes with the value of 2.3. These data are supporting MN as a relevant biomarker for children health. However, the data is mostly from small studies with different protocol leaving out the possibility of metanalyses and even statistical comparisons among studies. The actual risk from elevated MNs in children waits large cohort studies with pooled datasets as performed with MN measured in adults. Introduction of buccal cells as non invasive alternative to lymphocytes is increasing and as with the lymphocytes standardised protocols are recommended to enable comparative studies and metaanalyses.