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Sixteen surface (5) and groundwater (11) samples were collected from the south-eastern part of Attica, Greece, and analysed for physico-chemical parameters and microplastics (MPs) by optical microscopy and Raman microspectroscopy (RS). A total of 3399 particles were optically identified in all sixteen samples, ranging from only 16 particles/L in a sample from a deeper borehole to 513 particles/L in a sample from a shallow water well. They were then visually classified into eight categories based on their color, texture, size, reflectivity, shape, and general morphological properties. Raman microspectroscopy was performed on the particles on the filters and revealed four different types of MPs, namely polyethylene (PE, 35%), polypropylene (PP, 30%), polystyrene (PS, 10%), and polyethylene terephthalate (PET, 25%). The samples from the shallow phreatic aquifer contained more MPs than the samples from the deeper borehole, which contained fewer MPs and categories. This is to be expected, since the phreatic aquifer (a) is generally more contaminated, as it is close to human activities that generate MPs and its infiltration depth is only a few metres, which means that many microplastics can infiltrate at such shallow depths, and (b) it is exposed to the atmosphere, so they can also be suspended in the air. On the other hand, it is interesting to note that MPs, especially PET and PE, were detected in the borehole sample, suggesting that MPs can migrate to greater depths through water infiltration. Chemical analyses of the groundwater samples revealed high values of E.C., Ca2+, Mg2+, Cl−, and Na+, which indicate that seawater intrusion is taking place in the coastal aquifer system of the Erasinos basin. The increased concentrations of NO3− and PO43− also indicate the impact of agricultural activities.

Vitamin D deficiency (VDD) may be associated with obstructive sleep apnea (OSA) presence and is more pronounced with increasing OSA severity; however, the relationship between these two entities remains unclear. This was a cross-sectional study among 262 adults with in-hospital-attended polysomnography-diagnosed OSA and no additional major comorbidities, aiming to explore possible associations between serum 25-hydroxyvitamin D [25(OH)D] levels and polysomnographic parameters. Data on demographics, medical history, anthropometric indices, and lifestyle habits were collected at enrolment. Serum 25(OH)D was evaluated using chemiluminescence, with VDD defined as 25(OH)D < 20 ng/mL. VDD was observed in 63% of the participants. Serum 25(OH)D correlated negatively with apnea–hypopnea index and other polysomnographic indices (all p < 0.05). In logistic regression analysis, adjusting for age, sex, smoking, body mass index, physical activity, dietary vitamin D intake, and season of blood sampling, serum 25(OH)D was associated with lower odds of severe OSA [odds ratio (95% confidence interval): 0.94 (0.90–0.98)]. In the same multivariate model, VDD was associated with ~threefold higher odds of severe OSA [2.75 (1.38–5.48)]. In stratified analyses, VDD predicted OSA severity in the group of participants ≥50 y [3.54 (1.29–9.68)] and among those with body mass index ≥ 30 kg/m2 [3.38 (1.52–7.52)], but not in the younger and non-obese adults. This study provides further evidence of an inverse association between vitamin D levels and OSA severity and underscores the importance of considering vitamin D status as a potential modifiable factor in the comprehensive management of OSA.