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Mercury and Blood Pressure Levels in Inhabitants from a Highly Industrialized Region in Northern Portugal

Mon, 01 Jan 2024 00:00:00 GMT

Title: Mercury and Blood Pressure Levels in Inhabitants from a Highly Industrialized Region in Northern Portugal Authors: Pastorinho, M Ramiro; Barros, R; Valente, JV; Gonçalves, D; Taborda-Barata, L; Sousa, Ana Catarina Abstract: Objective: Estarreja is a highly industrialized municipality in NW Portugal, well known for its historical mercury contamination. Mercury exposure is a serious risk to human health (cf. Minamata Disease), and due to its widespread occurrence and persistency, it is recognized as a priority substance. Amongst the myriad deleterious effects of mercury on human health, hypertension has only recently gained attention. The aim of this work was to evaluate the levels of mercury in matched dust and hair samples from inhabitants of Estarreja; and to study possible associations between hypertension and mercury. Methods: House dust and hair samples from the residents of Estarreja were collected, together with systolic (SBP) and diastolic (DBP) blood pressure measurements. Mercury levels were analyzed by CV-AAS. Results: Levels of mercury in dust (93–9100 ng/g) were, on average, higher than those in hair (624–4535 ng/g). No statistically significant association between dust and hair could be established (Spearman Rank Order Correlation, p=0.199), reinforcing that dust is not the major exposure pathway to this toxicant. Twentyeight per cent of the participants were hypertensive. No statistically significant differences in mercury levels between the hypertensive and normal group were found (One-tailed P-value=0.444). No significant associations between SBP (p=0.826) or DBP (p=0.695) and hair mercury levels were obtained. Conclusions: Overall, 72% exhibited levels higher than the acceptable dose set by the USEPA (1000 ng/g), and 44% of individuals exhibited hair mercury levels higher than the WHO acceptable dose (2000 ng/g).

An optimized method for the preliminary detection of Microplastics in the Indoor Environment

Mon, 01 Jan 2024 00:00:00 GMT

Title: An optimized method for the preliminary detection of Microplastics in the Indoor Environment Authors: Valente, J; Pastorinho, Manuel; Sousa, Ana Catarina Abstract: Objective: Microplastics (MPs) are plastic particles with sizes between 100 nm and 5 mm, regarded as emerging contaminants and responsible for multiple deleterious effects on human health. Due to MPs ubiquity, humans are continuously exposed. However, exposure dosimetry is very rarely performed, particularly for the indoor environment. This work describes a simple protocol to evaluate the presence of MPs in the indoor environment. Methods: Passive dust samples were collected in two divisions (kitchen and bedroom) of the same house during one-week periods. Active dust samples were retrieved from the vacuum cleaner bag. Different methods for the extraction of MPs were tested, including the combination of density separation with sodium chloride and digestion with hydrogen peroxide. Since no standard protocol for MPs quantification in dust samples was available, the amount of dust to be used in the analysis was also optimized. The MPs were then visualized and identified by confocal microscopy after Nile Red staining. Results: For passive samples, only the oxidative digestion of the lipids content with H2O2 is necessary. For active samples, it is necessary to perform a density separation with NaCl prior to oxidative digestion. Overall, the results from the passive dust samples revealed that the bedroom exhibited a higher number of fibers than the kitchen and that the highest fluorescence intensity was also registered in the bedroom samples. Concerning the active samples, the optimization of the amount of dust to be analyzed indicated that a minimum of 0.5 g of the 63 µm dust fraction should be used. Conclusions: Nile Red visualization technique proved to be efficient in MPs detection and quantification. However, it cannot discern the composition of different MPs present in a sample. Hence, this technique should be used as a preliminary approach to confirm the existence/non-existence of MPs.

Daphnia magna: a viable, alternative model for Parkinson’s research

Mon, 01 Jan 2024 00:00:00 GMT

Title: Daphnia magna: a viable, alternative model for Parkinson’s research Authors: Coelho, S; Marques, D; Azevedo, AM; Cristovão, AC; Pastorinho, M Ramiro; Sousa, Ana Catarina Abstract: Objective: Despite a high level of toxicity, Paraquat is a widely used herbicide. Respiratory failure is the most severe consequence of acute poisoning, but a mechanistic link was also established to Parkinson’s disease (PD). Consequently, paraquat has become a reference neurotoxin used to induce Parkinson’s in experimental models, particularly mice. However, given the increasing restriction on the use of mammals in basic research, alternative models for PD research are needed. In line with this, we explored the possibility to use the invertebrate crustacean Daphnia magna. In this work we assessed paraquat’s acute toxicity to D. magna. Methods: Paraquat acute toxicity was evaluated in D. magna neonates using the OECD Protocol No.202, with slight modifications. Neonates with less than 24h were exposed to increasing concentrations of paraquat. After 24 and 48h of exposure, immobilization was evaluated and the EC50 (concentration responsible for 50% immobilization) was calculated. Since one of PD characteristics is movement disorders, daphnids’ movement after 24 and 48h was evaluated, and the heartbeat was also monitored. Results: Overall, the results disclosed large variations in mortality with EC50 values varying widely depending on the age of neonates, from 6.95 ± 1.32 mg.L-1 for 2h-old organisms and 10.22 ± 0.13 mg.L-1 for 20h-old organisms. The heartbeat was dependent on the paraquat concentrations, with higher heartbeat rates at higher concentrations. An opposite trend was observed in the Daphnia movement, with paraquat exposure being responsible for a reduction of movements at higher concentrations. Conclusions: Daphnia magna showed sensitivity to increasing concentrations of Paraquat, as demonstrated by variations of heart frequency and perturbations of movement. However, results showed age-dependent variability. As such, even though the OECD protocol recommends that acute tests should be performed with neonates with less than 24h, our results highlight the need to narrow the age range to ensure reproducibility.

Screeening the Microbiome of House Dust in the Alentejo Region

Mon, 01 Jan 2024 00:00:00 GMT

Title: Screeening the Microbiome of House Dust in the Alentejo Region Authors: Pastorinho, M Ramiro; Ramalhosa, R; Penha, A; Sousa, Ana Catarina Abstract: Objective: In this study, in the context of project HERO (Impact of Artificial Habitats and Environmental contaminants on Chronic RespiratOry Diseases), we conduct a pilot study to determine the presence of Sars-Cov-2 in house dust collected in Alentejo Region Homes. Methods: Seven volunteers were recruited to participate in this study to providing house dust samples obtained by vacuum cleaning (in a total of 16 samples collected between June 2021 and May 2023). Sample were sorted and sieved, and the <63 µm fraction used for nucleic acid extraction and after processing, amplified by RT-qPCR using the ALS SARS-CoV-2 commercial kit. Results: 83.3% of the samples tested positive for the presence of SARS-CoV-2. In 42% of the houses with positive detection, the occupants reported to have been Covid free. One of the houses tested around a whole year always had amplifiable virus in all collected samples despite a single positive test for one of the occupants being reported. In two of the samples only after dilution (1:5) was it possible to detect the virus. Conclusions: Infectious agents can be used as surrogates of Environmental Contaminants (chemical and biological) with potential effects in Chronic Respiratory Diseases’ symptoms/ exacerbations. Furhermore, indoor dust can be used as a straightforward, suitable and effective matrix for viral surveillance, being able to detect asymptomatic infections and, potentially, be used in early detection of spreading infections (particularly important in the presence of vulnerable people). The fact that only after dilution was possible to attain some detections, attests to the presence of PCR inhibiting chemicals, more prevalent in areas influenced by rural practices. The small number of houses sampled limits these conclusions.