a b s t r a c tEight tropical fruit pulps from Brazil were simultaneously characterised in terms of their antioxidant and antimicrobial properties. Antioxidant activity was screened by DPPH radical scavenging activity (126-3987 mg TE/100 g DW) and ferric reduction activity power (368-20819 mg AAE/100 g DW), and complemented with total phenolic content (329-12466 mg GAE/100 g DW) and total flavonoid content measurements (46-672 mg EE /100 g DW), whereas antimicrobial activity was tested against the most frequently found food pathogens.Acerola and açaí presented the highest values for the antioxidant-related measurements. Direct correlations between these measurements could be observed for some of the fruits. Tamarind exhibited the broadest antimicrobial potential, having revealed growth inhibition of Pseudomonas aeruginosa. Escherichia coli, Listeria monocytogenes, Salmonella sp. and Staphylococcus aureus.Açaí and tamarind extracts presented an inverse relationship between antibacterial and antioxidant activities, and therefore, the antibacterial activity cannot be attributed (only) to phenolic compounds.
The aim of this work is to diagnose the limnological conditions of the Castanhão Reservoir which is the largest and most important reservoir in the State of Ceará. This diagnosis is focused on physical-chemical variables, trophic state indices, and phytoplankton assemblages; Methods: Water samples were collected during six occasions from November/06 to July/07 from surface and bottom of the water column at three sites across the reservoir aiming to characterize physical-chemical (depth, transparency, suspended matter, temperature, dissolved oxygen, pH, redox potential, dissolved silicon, nitrogen and phosphorous) and biological (Chlorophyll-a, phytoplankton assemblages and total density) variables; Results: The trophic state index variables obtained for the reservoir showed Secchi disk depth ranging from 0.65 to 2.4 m, Chlorophyll-a from 0.71 to 15 µg.L-1 , total phosphorous from 11 to 369 µg.L-1 and soluble reactive phosphorous from 9.0 to 236 µg.L-1. The results characterized a riverine-lacustrine transition area with low depth, transparency, dissolved oxygen with one anoxic event, and high values of suspended matter, total phosphorous and ammonium. The reduced light availability is probably the main factor inducing the low values for total phytoplankton density and Chlorophyll-a. The predominant class of phytoplankton was Bacillariophyceae with main species Aulacoseira distans var. distans as functional assemblage C. Typical lacustrine portion of the reservoir has higher depth and transparency than inlet reservoir what probably explains the higher total phytoplankton density. Cyanophyceae was the predominante phytoplankton class with main species Cylindrospermopsis raciborski as functional assemblage Sn. The phytoplankton assemblages in the Castanhão Reservoir were typical for mesotrophic/eutrophic aquatic environments confirming the trophic state of the reservoir; Conclusion: After five years completely flooded, the Castanhão Reservoir might be considered a mesotrophic, although depletion of dissolved oxygen and presence of a potentially toxic phytoplankton species (C. raciborskii) suggests the necessity of reservoir management focused on anthropogenic nutrient emission control and maintenance of natural ecological succession of the reservoir.
How to cite: ArAÚJO gM, LIMA NETO IE AND BECKEr H. 2019. Phosphorus dynamics in a highly polluted urban drainage channel-shallow reservoir system in the Brazilian semiarid. An Acad Bras Cienc 91: e20180441.
A B S T R A C TThe aim of this study was to identify spatial and temporal variations in water quality of Orós reservoir, Ceará, Brazil, as well as the sources of contamination. To get this information the Principal Component Analysis (PCA) and Cluster Analysis (CA) was used. Water samples were collected at seven (geo-referenced) points, from April 2008 to March 2011, totalling 4,032 samples. The following attributes of the waters were analysed: temperature, pH, CE, Ca , turbidity, colour, Sechi transparency, TS, TVS, TFS, TSS, VSS, FSS, TDS, DO, BO 5D , total phosphorus, soluble orthophosphate, EC, TTC, total ammonia, TKN, nitrate, SAR and chlorophyll-a. The PCA promoted the reduction from the 32 initial variables to 14, accounting for 84.39% of the total variance. The major factors responsible for water quality composition are: the natural weathering of geological soil components; the entrainment of suspended solids through surface runoff from agricultural areas; and anthropogenic action in the Upper Jaguaribe basin in Ceará. The similarity of the water of the Orós reservoir allows a reduction in the number of sampling points, which may result in significant cost savings without sacrificing the water quality monitoring. The similarity of the waters was influenced by anthropic activities being carried out near the reservoir and all along the watershed.Investigação da qualidade das águas de um grande reservatório na região semiárida do Brasil R E S U M O Objetivou-se estudar, com esta pesquisa, a variabilidade espaço temporal da qualidade das águas do açude Orós, Ceará, além das variáveis determinantes desta qualidade razão pela qual foram empregadas a análise de componentes principais (ACP) e a análise de agrupamento hierárquico (AAH). As amostras de água foram coletadas em sete pontos (georreferenciados), no período de abril de 2008 a março de 2011, totalizando 4032 amostras. Nas águas foram analisados os seguintes atributos: temperatura, pH, CE, Ca , turbidez, cor, transparência de sechi, ST, STV, STF, SST, SSV, SSF, SDT, OD, DBO 5 , fósforo total, ortofosfato solúvel, EC, CTT, amônia total, NKT, nitrato, RAS e clorofila-a. A ACP promoveu redução das 32 variáveis iniciais para 14 variáveis explicando 84,39% da variância total. Os principais fatores responsáveis pela qualidade das águas do Orós foram: processo natural de intemperismo dos componentes geológicos do solo; carreamentos dos sólidos suspensos através do escoamento superficial das águas oriundas de áreas agrícolas e ações humanas ocorridas nas partes altas da bacia do Alto Jaguaribe. A similaridade das águas do Orós permite uma redução nos pontos de amostragem, o que pode resultar em menor custo sem comprometer o monitoramento da qualidade das águas. A similaridade das águas foi influenciada pelas atividades antrópicas exercidas nas proximidades do reservatório e ao longo da bacia.
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