Personal inhalation exposure to manganese and other trace metals in an environmentally exposed population: bioaccessibility in size-segregated particulate matter samples

Exposure to environmental airborne manganese (Mn) can lead to neurotoxic disorders and cognitive deficits. The degree of exposure can be assessed by personal sampling of particulate matter (PM) or through biomarkers of exposure. The aim of this work was to characterise the personal exposure to airborne Mn and other trace metals by measuring their bioaccessibility in PM filters taken from personal samplers in an environmentally exposed adult population living in the vicinity of a ferromanganese alloy plant in Santander Bay (northern Spain). Concentrations of bioaccessible and non-bioaccessible Mn and other metals associated with coarse (PM10-2.5) and fine (PM2.5) modes were quantified from 24 h personal samplers in 130 participants divided into two groups according to their Mn exposure: highly (n = 65) and moderately (n = 65) exposed. Gastric fluid and artificial lysosomal fluid (ALF) were used in the bioaccessibility tests as surrogate agents for the body fluids that can come into contact with coarse and fine particles, respectively. The mean air Mn levels in PM10-2.5 and PM2.5 were 127.2 and 126.2 ng/m3, respectively, in the highly exposed group, and 18.6 and 31.7 ng/m3 in the moderately exposed group. The bioaccessibility (%) of Mn in gastric fluid and ALF was also found to be greater in the highly exposed group. The results indicate that people living near Mn alloy plants have an increased potential health risk for Mn exposure due to higher total air Mn concentrations and bioaccessibility.This work was funded by the Spanish Ministry of Science, Innovation and Universities through Project CTM 2017-82636-R. Bohdana Markiv also thanks the same Ministry for her PhD grant, PRE 2018-085152

Environmental exposure to manganese and health risk assessment from personal sampling near an industrial source of airborne manganese

Manganese (Mn), despite being a trace element necessary in small quantities for the correct functioning of the organism, at higher concentrations can induce health disorders, mainly in motor and cognitive functions, even at levels found in non-occupational environments. For this reason, US EPA guidelines define safe reference doses/concentrations (RfD/RfC) for health. In this study, the individualised health risk of exposure to Mn through different media (air, diet, soil) and routes of entry into the organism (inhalation, ingestion and dermal absorption) was assessed according to the procedure defined by the US EPA. Calculations related to Mn present in ambient air were made on the basis of data obtained from size-segregated particulate matter (PM) personal samplers carried by volunteers recruited in a cross-sectional study conducted in the Santander Bay (northern Spain), where an industrial source of airborne Mn is located. Individuals residing in the vicinity of the main Mn source (within 1.5 km) were found to have a hazard index (HI) higher than 1, indicating that there is a potential risk for these subjects to develop health alterations. Also, people living in Santander, the capital of the region, located 7-10 km from the Mn source, may have some risk (HI > 1) under some wind conditions (SW). In addition, a preliminary study of media and routes of entry into the body confirmed that inhalation of PM2.5-bound Mn is the most important route contributing to the overall non-carcinogenic health risk related to environmental Mn.This work was supported by the Spanish Ministry of Science and Innovation (Project CTM2017-82636-R, funded by MCIN/AEI/10.13039/501100011033 and “ERDF A way of making Europe”). Bohdana Markiv also thanks the MICIU for her predoctoral contract (PRE2018-085152, financed together by MCIN/AEI/10.13039/501100011033 and “ESF Investing in your future”)

Impact of environmental airborne manganese exposure on cognitive and motor functions in adults: a systematic review and meta-analysis

Background/Objective: Whether environmental exposure to Manganese (Mn) in adults is associated with poorer results in cognitive and motor function is unclear. We aimed to determine these associations through a meta-analysis of published studies. Methods: A systematic review was conducted to identify epidemiological studies on a population _18 years old exposed to environmental airborne Mn, and in which results on specific tests to evaluate cognitive or motor functions were reported. We consulted Medline through PubMed, Web of Science and SCOPUS databases. We also performed a manual search within the list of bibliographic references of the retrieved studies and systematic reviews. To weight Mn effects, a random effects versus fixed effect model was chosen after studying the heterogeneity of each outcome. Results. Eighteen studies met the inclusion criteria. Among them, eleven studies reported data susceptible for meta-analysis through a pooled correlation or a standardized means difference (SMD) approach between exposed and non-exposed groups. Regarding cognitive function, the results of the studies showed heterogeneity among them (I2 = 76.49%, p < 0.001). The overall effect was a statistically significant negative correlation in the random effects model (pooled r = -0.165; 95%CI: -0.214 to -0.116; p < 0.001). For SMD, the results showed a lower heterogeneity with a negative SMD that did not reach statistical significance under the fixed effects model (SMD = -0.052; 95%CI -0.108 to 0.004; p = 0.068). Regarding motor function, heterogeneity (I2 = 75%) was also observed in the correlation approach with a pooled r (random effect model) = -0.150; 95%CI: -0.219 to -0.079; p < 0.001. Moderate heterogeneity was observed according to the SMD approach (I2 = 52.28%), with a pooled SMD = -0.136; 95%CI: -0.188 to-0.084; p < 0.001, indicating worse motor function in those exposed. Conclusions: Correlation approach results support a negative effect on cognitive and motor functions (the higher the Mn levels, the poorer the scores). Regarding the SMD approach, results also support a worse cognitive and motor functions in those exposed, although only for motor function statistical significance was obtained.This work was supported by the Spanish Ministry of Science, Innovation and Universities through the CTM2017-82636-R Project. This funding source was not involved in the study design; data collection, analysis, or interpretation; the writing of the article; or the decision to submit for publication

Bioaccessibility of trace metals in urban dust: effect of the synthetic body fluid composition and liquid to solid ratio

Máster en Ingeniería Químic

Characterization of fluorophores in biomedicine by spectrophotometry

Grado en Ingeniería Químic

Análisis de propiedades espectroscópicas de fluoróforos utilizados en el diagnóstico clínico

Las técnicas ópticas se emplean habitualmente en la práctica médica para el tratamiento y diagnóstico de patologías, incluyendo aplicaciones de cirugía. Entre sus ventajas frente a técnicas que emplean radiaciones en otras bandas del espectro electromagnético u ondas acústicas, se encuentran su carácter no ionizante, no invasivo o mínimamente invasivo, la capacidad de localización precisa y la ausencia de contacto. Una de las técnicas diagnósticas más relevantes utiliza el fenómeno de la fluorescencia aplicada al ámbito biomédico. La fluorescencia es un fenómeno producido por la interacción entre un material y la radiación óptica, de tal forma que es capaz de reemitir radiación a longitudes de onda distintas, habitualmente superiores. Las características diagnósticas dependen fuertemente del tipo de fluoróforo empleado, que debe también cumplir restricciones de biocompatibilidad para su aplicabilidad biomédica. Este trabajo se focaliza en dos fluoróforos aprobados para uso clínico: azul de metileno y verde de indocianina. El objetivo consiste en analizar experimentalmente las características espectrales, fundamentalmente de excitación, lo que resulta imprescindible para su uso eficiente en la práctica clínica. Se analiza esta dependencia espectral con diferentes disolventes y a diferentes concentraciones. De esta forma es posible conocer los rangos de longitudes de onda óptimos para su aplicación clínica diagnóstica.Este trabajo ha sido parcialmente financiado por los proyectos del Plan Nacional de I+D+i “Nuevas fases activas en nano-óxidos de metales de transición y tierras raras estabilizadas a alta presión” (MAT2015-69508-P), y Acción Estratégica en Salud ”Electroencefalografía intracortical en pacientes con daño cerebral agudo” (PI17/00156), cofinanciados con fondos FEDER, y por la Fundación San Cándido

Short- and long-term exposure to trace metal(loid)s from the production of ferromanganese alloys by personal sampling and biomarkers

The environmental exposure to trace metal(loid)s (As, Cd, Cu, Fe, Mn, Pb, and Zn) was assessed near a ferromanganese alloy plant using filters from personal particulate matter (PM) samplers (bioaccessible and non-bioaccessible fine and coarse fractions) and whole blood as short-term exposure markers, and scalp hair and fingernails as long-term biomarkers, collected from volunteers (n = 130) living in Santander Bay (northern Spain). Bioaccessible and non-bioaccessible metal(loid) concentrations in coarse and fine PM from personal samplers were determined by ICP-MS after extraction/digestion. Metal(loid) concentration in biomarkers was measured after alkaline dilution (whole blood) and acid digestion (fingernails and scalp hair) by ICP-MS as well. Results were discussed in terms of exposure, considering the distance to the main Mn source, and sex. In terms of exposure, significant differences were found for Mn in all the studied fractions of PM, As in whole blood, Mn and Cu in scalp hair and Mn and Pb in fingernails, with all concentrations being higher for those living closer to the Mn source, with the exception of Cu in scalp hair. Furthermore, the analysis of the correlation between Mn levels in the studied biomarkers and the wind-weighted distance to the main source of Mn allows us to conclude that scalp hair and mainly fingernails are appropriate biomarkers of long-term airborne Mn exposure. This was also confirmed by the significant positive correlations between scalp hair Mn and bioaccessible Mn in coarse and fine fractions, and between fingernails Mn and all PM fractions. This implies that people living closer to a ferromanganese alloy plant are exposed to higher levels of airborne metal(loid)s, mainly Mn, leading to higher levels of this metal in scalp hair and fingernails, which according to the literature, might affect some neurological outcomes. According to sex, significant differences were observed for Fe, Cu and Pb in whole blood, with higher concentrations of Fe and Pb in males, and higher levels of Cu in females; and for Mn, Cu, Zn, Cd and Pb in scalp hair, with higher concentrations in males for all metal(loid)s except Cu.This work was supported by the Spanish Ministry of Science and Innovation (Project CTM2017-82636-R, funded by MCIN/AEI/10.13039/501100011033 and “ERDF A way of making Europe”). Bohdana Markiv also thanks the MICIU for her predoctoral contract (PRE2018-085152, financed together by MCIN/AEI/10.13039/501100011033 and “ESF Investing in your future”)