Somatosensory psychophysic losses in inhabitants of riverside communities of the Tapajós river basin, Amazonas, Brazil: The possible involvement of exposure to methylmercury

Abstract

Complementary examsThrombocytosis, basic biochemistry, and normal serologies. Cerebrospinal fluid tests showed increased protein content. Electroneuromyography revealed sensorimotor polyneuropathy with a demyelinating pattern and less axonal loss. Computed tomography revealed lymphadenopathy in several chains, and many sclerotic bone lesions. A bone marrow biopsy contained 10% of plasma cells. Protein electrophoresis of the urine showed a lambda monoclonal peak. The vascular endothelial growth factor (VEGF) was 300 times higher than the reference value. Discussion and final commentsThe association of demyelinating polyneuropathy with a monoclonal peak in the electrophoresis results and findings of sclerotic bone lesions, the elevation of VEGF, lymph node organomegaly, and endocrinopathy, confirm the diagnosis of POEMS Syndrome.In this syndrome, neurological damage usually develops with a demyelinating pattern, greater axonal loss, and autonomic preservation. However, we report an atypical case, of neurological impairment with less axonal loss; and relevant dysautonomia.

Mercury Exposure in Munduruku Indigenous Communities from Brazilian Amazon: Methodological Background and an Overview of the Principal Results

“…As well as being described by Khoury et al [16], Santos Freitas et al [17], Domingues et al [18], Pinheiro et al [19], Marinho et al [20], Vega et al [76], Barbieri and Gardon [113], our findings suggest that the proximity of the investigated communities with the gold mining activities is related to higher levels of methylmercury in hair samples. The comparative analyses performed on the communities revealed that in the Sawré Aboy village, which is located closer to gold mining operations, the greater hair Hg concentrations were reported.…”

“…Mercury has been a valuable metal in various industrial processes, particularly in gold mining activities and especially in developing countries surrounding the Amazon basin. This apparent economic benefit is insignificant compared to its severe environmental and neurotoxicological health impact [4][5][6][15][16][17][18][19][20]93]. The present study provides evidence that communities living in the Tapajos River basin in the Munduruku indigenous territories have a mean level of Hg exposure surpassing the safety limit (6.0 µg/g) recognized by the World Health Organization [69].…”

“…Moreover, the impact of gold mining on human mercury exposure has been evaluated in several cross-sectional studies involving control groups (i.e., populations living in areas with no history of mining activity) [16][17][18][19][20]. These studies reveal that the mercury levels detected in hair samples collected from groups living in areas impacted by mining are considerably higher than the levels observed in control groups.…”

Neurological Impacts of Chronic Methylmercury Exposure in Munduruku Indigenous Adults: Somatosensory, Motor, and Cognitive Abnormalities

“…The impact of gold mining on human mercury exposure has been described by some studies that compared exposed populations to control groups (for example, populations living in areas with no previous history of mining activities) [ 16 , 69 , 70 , 71 , 72 ]. These studies indicate that hair mercury levels detected in areas impacted by mining activities are considerably higher than those observed in control groups.…”