Neurocognitive impact of metal exposure and social stressors among schoolchildren in Taranto, Italy

BACKGROUND: Metal exposure is a public health hazard due to neurocognitive effects starting in early life. Poor socio-economic status, adverse home and family environment can enhance the neurodevelopmental toxicity due to chemical exposure. Disadvantaged socio-economic conditions are generally higher in environmentally impacted areas although the combined effect of these two factors has not been sufficiently studied. METHODS: The effect of co-exposure to neurotoxic metals including arsenic, cadmium, manganese, mercury, lead, selenium, and to socio-economic stressors was assessed in a group of 299 children aged 6-12\u2009years, residing at incremental distance from industrial emissions in Taranto, Italy. Exposure was assessed with biological monitoring and the distance between the home address and the exposure point source. Children's cognitive functions were examined using the Wechsler Intelligence Scale for Children (WISC) and the Cambridge Neuropsychological Test Automated Battery (CANTAB). Linear mixed models were chosen to assess the association between metal exposure, socio-economic status and neurocognitive outcomes. RESULTS: Urinary arsenic, cadmium and hair manganese resulted inversely related to the distance from the industrial emission source (\u3b2 -\u20090.04; 95% CI -0.06, -\u20090.01; \u3b2 -\u20090.02; 95% CI -0.05, -\u20090.001; \u3b2 -\u20090.02 95% CI -0.05, -\u20090.003) while the WISC intellectual quotient and its sub-scores (except processing speed index) showed a positive association with distance. Blood lead and urinary cadmium were negatively associated with the IQ total score and all sub-scores, although not reaching the significance level. Hair manganese and blood lead was positively associated with the CANTAB between errors of spatial working memory (\u3b2 2.2; 95% CI 0.3, 3.9) and the reaction time of stop signal task (\u3b2 0.05; 95% CI 0.02, 0.1) respectively. All the other CANTAB neurocognitive tests did not show to be significantly influenced by metal exposure. The highest socio-economic status showed about five points intellectual quotient more than the lowest level on average (\u3b2 4.8; 95% CI 0.3, 9.6); the interaction term between blood lead and the socio-economic status showed a significant negative impact of lead on working memory at the lowest socio-economic status level (\u3b2 -\u20094.0; 95% CI -6.9, -\u20091.1). CONCLUSIONS: Metal exposure and the distance from industrial emission was associated with negative cognitive impacts in these children. Lead exposure had neurocognitive effect even at very low levels of blood lead concentration when socio-economic status is low, and this should further address the importance and prioritize preventive and regulatory interventions

Hg2+ detection by measuring thiol groups with a highly sensitive screen-printed electrode modified with a nanostructured carbon black film

A sensor based on a screen-printed electrode (SPE) modified with a stable dispersion of commercially available carbon black (CB) N220 was optimised and challenged with several thiol-containing compounds. This probe showed a significantly enhanced electrochemical activity respect to a bare SPE when tested with thiocholine, cysteine, glutathione and cysteamine. When challenged in amperometric batch mode, the response was stable and showed a linear dependence up to 1 × 10-5 mol l-1 for thiocholine and cysteine. The very high sensitivity towards these thiols (299 mA mol -1 l cm-2 for thiocholine and 441 mA mol-1 l cm-2 for cysteine) was then used as the basis for developing an analytical method for mercury ion detection since a non electroactive complex (thiol-Hg) is formed in the presence of the metal. By selecting an appropriate concentration of thiocholine, a concentration of mercury as low as 5 × 10-9 mol l-1 (1 ppb) was detected. Satisfactory recovery was obtained when the system was tested on drinking water samples

Monitoring of alcohol-based hand rubs in SARS-CoV-2 prevention by HS-GC/MS and electrochemical biosensor: A survey of commercial samples

Alcohol-based hand rubs (ABHRs) have found large diffusion during the Severe Acute Respiratory Syndrome Coronavirus 2, SARS-CoV-2, thus becoming the most widespread means for hand hygiene. Whereby, it is fundamental to assess the alignment of commercial ABHRs to the indications provided by the principal health agencies regarding alcohol content and possible impurities. In this work, a novel improvement of previous existent methods for the determination of alcohol content in such products was reported. In particular, two alternative sensitive and reproducible methods, such as an electrochemical screen-printed based enzymatic (alcohol oxidase) biosensor and a Headspace Gas Chromatography coupled with Mass Spectrometry (HS-GC/MS) were proposed. The electrochemical device represents a rapid, low-cost and accurate fraud screening method for alcohol-based hand rubs. The second technique confirms, identifies and simultaneously determines ethyl alcohol, isopropyl alcohol, n-propyl alcohol and methyl alcohol, improving their extraction through acidification in the sample pre-treatment step. The developed specific HS-GC/MS method was in-house validated according to ISO/IEC 17025 requirements. Analytical parameters such as limit of detection (LoD 0.13%v/v - 0.17%v/v), limit of quantification (LoQ 0.44% v/v - 0.57% v/v), inter-day repeatability (RSDR 2.1–10.7%) and recovery (80–110%) were assessed. The relative expanded uncertainties range (between 0.1%v/v and 3.4%v/v) for all the analytes were evaluated. Results obtained using the different analytical approaches were compared and indicated that the two data sets were comparable (median; HS-GC/MS, 56%v/v; electrochemical biosensor, 62%v/v) and were not statistically different (one-way ANOVA test; p = 0.062). In addition, a good correlation (95%) was found. This study noticed that only 39% of the tested hand sanitiser products had the recommended average alcohol content, thus highlighting the need for analytical controls on this type of products

Associations among Exposure to Methylmercury, Reduced Reelin Expression, and gender in the Cerebellum of Developing Mice

Genetic risk factors acting during pregnancy or early after birth have been proposed to account for the exponential increase of autism diagnoses in the past 20 years. In particular, a potential link with exposure to environmental mercury has been suggested. Male sex constitutes a second risk factor for autism. A third potential genetic risk factor is decreased Reelin expression. Male heterozygous reeler (rl(+/-)) mice show an autism-like phenotype, including Purkinje cells (PCs) loss and behavioural rigidity. We evaluated the complex interactions between 3 risk factors, i.e. genetic status, sex, and exposure to methylmercury (MeHg), in rl(+/-) mice. Mice were exposed to MeHg during the prenatal and early postnatal period, either at a subtoxic dose (2ppm in Dams' drinking water), or at a toxic dose (6ppm Dams' drinking water), based on observations in other rodent species and mice strains. We show that: a) 2ppm MeHg does not cause PCs loss in the different animal groups, and does not enhance PCs loss in rl(+/-) males; consistent with a lack of overt neurotoxicity, 2ppm MeHg per se does not cause behavioural alterations (separation-induced ultrasonic calls in newborns, or sociability and social preference in adults); b) in stark contrast, 6ppm MeHg causes a dramatic reduction of PCs number in all groups, irrespective of genotype and sex. Cytochrome C release from mitochondria of PCs is enhanced in 6ppm MeHg-exposed groups, with a concomitant increase of μ-calpain active subunit. At the behavioural level, 6ppm MeHg exposure strongly increases ultrasonic vocalizations in all animal groups. Notably, 6ppm MeHg significantly decreases sociability in rl(+/-) male mice, while the 2ppm group does not show such as decrease. At a subtoxic dose, MeHg does not enhance the autism-like phenotype of male rl(+/-) mice. At the higher MeHg dose, the scenario is more complex, with some "autism-like" features (loss of sociability, preference for sameness) being evidently affected only in rl(+/-) males, while other neuropathological and behavioural parameters being altered in all groups, independently from genotype and sex. Mitochondrial abnormalities appear to play a crucial role in the observed effects