Dissertação de Mestrado
Avaliação do impacto ambiental de duas truticulturas em raceway sobre seus córregos receptores
Fecha
2016-09-12Autor
Jose Antonio Beirao Simoes
Institución
Resumen
The objective of this study was to evaluate, using physicochemical and biological analyzes, the impact of the effluent discharge of two trout farms in the associated streams, located in Delfim Moreira-MG, in the Mantiqueira sierra region. The NR Trutas with 23 tanks, some in series and some in parallel with an approximate volume of 65 m³ each, specialized in rearing trout, producing about 120 tons of trout annually in own refrigerator, with a daily consumption of approximately 625 kg of feed and with an average water inlet of approximately 1,000 L.s-1. Six collection points, NR1 to NR6, were selected. The NR1 point was located at the main entrance of the trout farm. NR2, NR3 and NR4 were located in different points of discharge in the trout farm. The NR5 point was located down the stream and the NR6 up the stream (Bicas river). The Truticultura Brumado has kept a stock of breeders, approximately 900, being 600 females and 300 males, making an approximate stock of 1,350 kg with an average consumption of 30 kg of feed.day-1 in six tanks in series, and performs reproduction in the period from May to August, when the temperature becomes ideal for reproduction (between 10-15°C), producing 120,000 to 150,000 fingerlings.year-1 with an average of water input of 17 L.s-1. Nine water points of collection, BR1 to BR9 were selected, as follows: BR1 point at the inlet of the trout farm, and BR2, BR3, BR4, BR5, BR6 and BR7 points at the outlets of the tanks (wastewater). The BR8 located up the stream and BR9 down the stream from the Brumado stream. The following water parameters were analyzed according to Standard Methods Water and Wastewater (APHA, 2008): biochemical oxygen demand (BOD), dissolved oxygen (DO), ammonia (NH3+NH4+), nitrite (NO2-), nitrate (NO3-), phosphate (PO43-), alkalinity and turbidity. Temperature, pH, electrical conductivity (EC), total dissolved solids (TDS) and salinity were analyzed in locu. Thermo-tolerant coliforms were also analyzed in the NR1, NR4, NR5 and NR6 points in NR Trutas, as well as, in BR1, BR7, BR8 e BR9 in Truticultura Brumado. Significant statistic differences (p<0.05) were found between the points NR1 and NR3, NR4 and NR6 for pH (decreasing), between the points NR1 and NR2 for DBO and between points NR1 and NR2, NR3 and NR4 for ammonia (increase), but there were no statistic differences in any other parameter between upstream (NR5) and downstream (NR6) of the river. In Truticultura Brumado significant differences (p<0.05) in STD, CE and turbidity, among BR1 and BR8, BR9, and among BR1 and BR4, BR5, BR6, BR7 for ammonia, and among BR5 and BR9 for DBO. For fecal coliforms were no statistically significant differences (p>0.05) between NR1 and NR4, NR5 and NR6 points, but significant differences were observed between the BR1 and BR7, BR8 and BR9 points in Truticultura Brumado. However, for all parameters analyzed there were no significant statistic differences between the point up the stream (BR8) and down the stream (BR9) of Brumado river, where the effluents were released. It was concluded that there were no significant differences (p>0.05) between upstream and downstream effluents samples. These changes are within the comfort standards for cultivated and levels of compliance with the release pattern of the specific legislation effluent species. Thus, the results obtained, the impact on bodies of water was minimal, but more studies are needed, including considering possible changes in environmental ecology (mainly benthic macroinvertebrates).