Geochemical background concentrations of potentially toxic elements in soils of the Carajás Mineral Province, southeast of the Amazonian Craton.

The objective of this study was to establish background concentrations of potentially toxic elements (PTEs) in soils from the Carajás Mineral Province (CMP), southeastern Amazonian Craton. The PTEs Al, Ba, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Ti, V, and Zn were digested in microwaves and quantified by optical emission spectrometry (ICP OES). The variability of physical-chemical and mineralogical attributes contributed to variation in PTE concentrations. High background concentrations of Al, Fe, Cr, Mn, Mo, Ni, Ti, and V and, in particular, the PTE concentrations of Cd, Cu, Cr, Ba, and Co were greater than the prevention values defined by the Brazilian National Council of Environment. Soil quality reference values (QRVs) were greater than those determined for most Brazilian states and soils in the state of Pará. The high background concentrations and QRVs of PTEs show that the region is strongly influenced by the source material, rich in ferruginous deposits and other associated minerals. The results are an important tool for establishing soil quality standards and public policies for environmental protection in regions naturally PTE enriched.

Prevalence and risk indicators of non-carious cervical lesions in male footballers.

BACKGROUND: Non-carious cervical lesions (NCCLs) have shown a significant incidence and prevalence and have been increasingly associated with people's lifestyles and youths. This cross-sectional study aimed to determine the prevalence of NCCLs in footballers and to address potential risk indicators. METHODS: Fourty-three male semi-professional footballers with an average of 27 years old completed a questionnaire and were subjected to intraoral examination in terms of cervical tooth wear, morphological characteristics of NCCLs, tooth sensitivity, occlusal/incisal wear, and malocclusion classification. Also, laboratory assays were performed to determine salivary parameters: flow rate, pH, buffer capacity, level of Ca (calcium), Na (sodium), and K (potassium) ions, and level of cortisol. The data obtained from the questionnaire and intraoral examinations were subjected to Chi-square and Poisson regression models while the data obtained from the laboratory assays were analyzed by using analysis of variance (p <  0.05). RESULTS: The prevalence of NCCLs was 39.5%. The participants presented predominantly initial lesions with signs of mechanical stress. The daily training time was found as a significant risk indicator (p = 0.028). The multivariate analysis showed a significant difference in the variables daily training time (p = 0.023), lemon water intake while fasting (p = 0.002), toothpaste type (p = 0.004), tooth sensitivity (p = 0.006); previous orthodontic treatment (p = 0.003), and occlusion type (p = 0.008). All participants presented normal salivary parameters and levels of cortisol. CONCLUSION: The prevalence of NCCLs among footballers was remarkable. The premolars were the most affected teeth and presented symptoms/signs of initial lesions. The daily training time was a dominant risk indicator of NCCLs development. Footballers presented adequate salivary parameters and cortisol levels.

Quality index of the surface water of Amazonian rivers in industrial areas in Pará, Brazil.

In this study was to evaluate the waters quality of the Murucupi River, located in urban agglomerate area and intense industrial activity in Barcarena City, Pará State. The Arapiranga River in Abaetetuba City was used as control area (Background), next to Barcarena. Was used the Water Quality Index (WQI) based on nine variables analized. Waters quality of the Arapiranga and Murucupi rivers were regular to good and bad to good, respectively. Anthropogenic influence on the Murucupi River was higher, mainly by the disposal of domestic effluents from the urban agglomerate and of the industrial waste tailing basins upstream of this river. Due to its less inhabited environment and further away from the area urban and industrial, the Arapiranga River was more preserved. Waters pollution of around these area is increasingly intense, and restricted its uses for various purposes.

Chemical Composition and Microhardness of Human Enamel Treated with Fluoridated Whintening Agents. A Study in Situ.

BACKGROUND: Dental whitening has been increasingly sought out to improve dental aesthetics, but may cause chemical and morphological changes in dental enamel surfaces. OBJECTIVE: Assess in situ the effects of high-concentration hydrogen peroxide with and without fluoride on human dental enamel using the ion chromatography test (IC) and the Knoop hardness test (KHN). MATERIAL AND METHODS: Nineteen enamel specimens were prepared using third human molars. These specimens were fixed on molars of volunteers and were divided into groups: OP38-Opalescence Boost PF38%, PO37-Pola Office 37.5% and CO-Control group. For chemical analysis (n= 3), the dentin layer was removed, keeping only the enamel, which was subjected to acidic digestion by microwave radiation. It was necessary to perform sample dilutions for the elements fluorine (F), calcium (Ca) and phosphorus (P) for quantification using the IC test. The KHN (n= 5) was performed before and after the treatments. Five indentations were made, separated by 100 µm, for each specimen using a load of 25 gf for 5 seconds in the microdurometer. The data were analyzed using ANOVA with a 5% significance level. RESULTS: The OP38 group had the largest concentrations of F, Ca and P ions. The PO37 group showed the lowest concentrations of F and Ca ions. The average KHN was not significantly different between the OP38 and PO37 groups. CONCLUSION: Enamel whitened with hydrogen peroxide containing fluoride had greater concentrations of F, Ca and P ions. The presence of fluoride in the whitening agent did not influence the enamel microhardness.

Assessment of risk to human health from simultaneous exposure to multiple contaminants in an artisanal gold mine in Serra Pelada, Pará, Brazil.

Contamination of soil, water and plants caused by gold mining is of great societal concern because of the risk of environmental pollution and risk to human health. The aim of the present study was to evaluate the risk to human health from ingestion of As, Ba, Co, Cu, Cd, Cr, Ni, Pb, Se and Ni present in soil, sterile and mineralized waste, and water and plants at a gold mine in Serra Pelada, Pará, Brazil. Samples of soil, sterile and mineralized waste, water and plants were collected around an artisanal gold mine located in Serra Pelada. The mean concentrations of potentially toxic elements in the soil were higher than the soil quality reference values as defined in the legislation, which may be attributeable to past mining activities. Water from the area close to the mine exhibited As, Ba and Pb concentrations exceeding the reference values established by the World Health Organization, deemed unfit for human consumption. Plants exhibited high Pb concentrations, representing a food safety risk to the population. The mean hazard index (HI) values were below the acceptable limit (1.0) established by the United States Environmental Protection Agency, although the highest HI values observed for adults and children were higher than the respective acceptable limits. Environmental contamination and risk to human health were heterogeneous in the surroundings of the mine. Mitigation strategies need to be adopted to decrease the risks of contamination to the environment and to the local population.