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Groundwater Quality Assessment in Rural Areas of Caapiranga City in Brazilian Amazon
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作者 juan daniel villacis fajardo Tainára Cunha Gemaque +3 位作者 Giovanni Resende de Oliveira Thiago Archangelo Freato Nancy Andrea villacis fajardo daniel Pereira da Costa 《Journal of Agricultural Science and Technology(B)》 2022年第1期16-23,共8页
About 75% of the entire surface of the planet Earth is covered by water, with only about 3% of freshwater. The Amazon region has the largest freshwater basin in the world and the uncontrolled growth of the population ... About 75% of the entire surface of the planet Earth is covered by water, with only about 3% of freshwater. The Amazon region has the largest freshwater basin in the world and the uncontrolled growth of the population in this region has become a problem concerning water contamination since a large part of the region’s population obtains water from artesian wells. This study aimed to investigate some physical-chemical parameters of groundwater in the municipality of Caapiranga, Amazonas (AM), Brazil. Water samples obtained from 14 tubular wells were evaluated, as well as a sample of surface water from Lake Caapiranga that passes in front of the municipality. The vast majority of water samples showed low pH, and were of the parameters established for drinking water, aquaculture and animal watering. High levels of nitrate are also found in most samples, which indicates contamination of these waters by domestic effluents. In wells 1, 6, 9 11, and 13 the levels of nitrate were very high and can cause serious diseases in people who use this water for consumption. According to the parameters evaluated, the quality of groundwater in 5 of the 14 wells is unfit for human consumption. 展开更多
关键词 Water quality human consumption AQUACULTURE animal consumption HYDROGEOCHEMISTRY POLLUTION
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Economic Analysis of the Use of Restrictive Food Management in the Cultivation of Tilapia(Oreochromis niloticus)in a Recirculation System
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作者 Giovanni Resende de Oliveira Thiago Archangelo Freato +3 位作者 juan daniel villacis fajardo Tainára Cunha Gemaque Nancy Andrea villacis fajardo daniel Pereira da Costa 《Journal of Agricultural Science and Technology(B)》 2022年第2期31-39,共9页
The development of more adequate food programs regarding the intensity and duration of the restriction can be an effective way to minimize the effects of exaggerated food consumption and its negative consequences for ... The development of more adequate food programs regarding the intensity and duration of the restriction can be an effective way to minimize the effects of exaggerated food consumption and its negative consequences for the economy of the business.In this sense,juvenile Nile tilapia(Oreochromis niloticus)(137±3 g)were submitted to different feeding strategies in a recirculation system.Five feeding strategies were tested in subsequent weekly cycles:continuous feeding;skipping one meal a week;suppression of two non-consecutive meals a week;suppression of three non-consecutive meals a week;suppression of four non-consecutive meals a week.Productive performance,feed consumption in the post-restriction period and economic indicators were evaluated through projections and profitability analyses.Compensatory intake occurred in all tested groups,so that the total feed intake(FI)did not differ significantly between them(p>0.05).Moderate food restriction provided a linear increase in the relative gross margin for each treatment with each change in salary level,as well as greater profitability when compared to the respective control group(p<0.05). 展开更多
关键词 Feed management feed restriction carcass quality carcass yield operational yield economic efficiency
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