Rainwater geochemistry inside the Barcarena power station at the mouth of the Tocantins River.

Most of South America lacks studies on rainwater composition. The present study evaluates rainwater composition and bulk deposition inside Barcarena power station, located at the mouth of the Tocantins River with Amazon River in Brazil. In 2012, 24-h rainwater samples were collected inside the ELETRONORTE power plant (n = 93), and pH, EC, cations and anions were analyzed. In order of abundance, the rainwater ions were Na+ > Cl- > SO4-2 > Ca+2 > K+ > F- > Mg+2 > NH4+-N > NO3--N. pH values ranged from 4.5 to 6.9, with 17 events with pH <5.6 and 5 events with pH < 5.0. Sodium and Cl- were the dominant ions with sea salt as main contribution. Acidity, enrichment factors and principal component analysis (PCA) indicate that F-, SO4-2 and NO3--N in the rainwater came from anthropogenic sources. Fluoride correlated strongly (>0.85) with Ca+2 and Mg+2, likely originated from same source in the aluminum production chain. Potassium originated from a mixture of anthropogenic and natural sources, with a good correlation (>0.70) with NO3--N and NH4+-N, indicating biomass burning and fertilizer origins. In 2012, Barcarena total bulk deposition ranged from 14,070 to 17,890 mg m-2 y-1 with significant contributions of SO4-2 (2,385 to 2,851 mg m-2 y-1), F- (419 to 479 mg m-2 y-1) and NO3--N (128 to 280 mg m-2 y-1). EC values (4 to 254 µS cm-1) indicated a medium site pollution severity (> 175 µS cm-1), which increased the risk of damage to electrical components.Highlights Chemical characterization of Barcarena, PA/Brazil rainwater in 2012 events.Apportionment sources of ionic rainwater content evaluated by acidity fraction, enrichment factors and principal component analysis.Anthropic fluoride, sulfate and nitrate local deposition values were compared with other regional data.Maintenance procedure recommendations under identified atmospheric deposition.

Understanding the mobility of potential nutrients in rock mining by-products: An opportunity for more sustainable agriculture and mining.

The increase in demand for highly soluble fertilizers brings a global sustainability concern. Alternative sources for traditional fertilization are therefore needed. Rock powder use has been proposed as an alternative approach to soil remineralization. However, research on the agricultural potential of minerals and rocks as alternative sources of nutrients is limited to changes in soil chemical attributes or effects on crop yield. In this work, we report an experimental study addressing the dissolution of two silicate rock-derived powders (andesite and dacite) that were produced during mining activities in Southern Brazil. The rock powders were exposed to Milli-Q water at pH (7.4-8.8) range, in solutions of 0.1 mol L-1 citric acid at pH range 2.1-3.3, and Milli-Q water acidified with 0.5 mol l-1 acetic acid (pH 5-5.8), in a continuous mechanical rotatory shaker at room temperature. Dissolution kinetics were determined as a function of reaction times at 24 to 5760 h, and solution pH. Based on this kinetics, dissolution rates were determined for the individual powders and compared to expected values for aluminosilicates. Based on this comparison, it was shown that the application of andesite and dacite rock-derived powder to replace high soluble fertilizers is feasible due to high dissolution rates of their minerals. The average andesite dissolution rates in Milli-Q water, in citric acid solution, and in Milli-Q water acidified with acetic acid were 2.1 × 10-5, 1.92 × 10-1 and 6.3 × 10-4 mmol cm-2 s-1, respectively for Ca, being 183%, 22.6%, and 69.2% higher than for the dacite rock. This make andesite rock a potential substitute for carbonate-based liming. In contrast, the average dacite dissolution rates in Milli-Q water, in citric acid solution, and in Milli-Q water acidified with acetic acid were 1.05 × 10-5, 7.22 × 10-5, and 3.72 × 10-5 mmol cm-2 s-1, respectively for K, being 72.0%, 61.4%, and 73.6% higher than the andesite rock. This highlights its potential use as a K source for agriculture to replace highly soluble K-fertilizers.

Spectroscopic methods and in silico analyses using density functional theory to characterize and identify piperine alkaloid crystals isolated from pepper (Piper Nigrum L.).

Communicated by Ramaswamy H. Sarma.

Gobioides broussonnetii (Gobiidae): a new host for Pterobothrium crassicolle (Trypanorhyncha) on Marajó Island, northern Brazil.

In the present study, the cestoid Pterobothrium crassicolle Diesing, 1850 (Trypanorhyncha), was observed parasitizing specimens of the violet goby (Gobioides broussonnetii Lacepède, 1800) collected from the estuary of the Paracauarí River on Marajó Island in the north of the Brazilian state of Pará, between January 2009 and December 2010. Tissue samples were analyzed, which led to identification of blastocysts containing plerocercoid larvae. These larvae were processed for scanning electron microscopy. Sixty G. broussonnetii specimens were dissected, and P. crassicolle was found in 48 (80%) of them. The violet goby, G. broussonnetii, is a new host for P. crassicolle.