Avaliação da qualidade de água no processo de recuperação de áreas de plantio de Pinus taeda em APP na bacia do Rio Campinas - Joinville - SC

Abstract

Resumo: Este trabalho apresenta uma avaliacao da influencia sobre a qualidade de agua do processo de recuperacao de talhoes de plantio de Pinus taeda em Area de Preservacao Permanente na bacia do rio Campinas, no municipio de Joinville, Santa Catarina, Brasil. Foram monitoradas 4 microbacias experimentais, sendo 3 delas com plantios de pinus, e uma com area de floresta nativa, mantida como testemunha, alem de dois pontos de monitoramento sobre o rio Campinas, um a montante e outro a jusante do reflorestamento. Utilizaram-se no monitoramento os parametros temperatura da agua, pH, condutividade eletrica (CE), oxigenio dissolvido (OD), demanda bioquimica de oxigenio (DBO), turbidez (TB), solidos dissolvidos totais (SDT), solidos suspensos totais (SST), nitrogenio total (NT), nitrato (N-NO3 -), fosforo total (PT) e potassio (K), assim como vazao (Q) e indices pluviometricos, entre fevereiro de 2007 a junho de 2011. A extracao dos pinus das Areas de Preservacao Permanente teve inicio em junho de 2008. Mapeamentos de uso de solo foram realizados para o periodo anterior e posterior ao corte, quantificando e espacializando as alteracoes na cobertura vegetal entre os dois periodos. A analise fatorial foi aplicada com objetivo de identificar quais os parametros de qualidade de agua sofreram maiores variacoes no decorrer do monitoramento e reconhecer o padrao de comportamento das variaveis em resposta as modificacoes do uso do solo. Observaram-se elevacoes na temperatura, pH, turbidez, solidos suspensos totais e fosforo total, e diminuicao na concentracao de oxigenio dissolvido apos o corte raso dos pinus das zonas riparias. Contudo, os parametros de qualidade de agua mantiveram-se de acordo com os padroes estabelecidos pela Resolucao Conama 357/05 na maior parte do monitoramento, registrando-se eventos isolados em que a turbidez, DBO e fosforo total estiveram em desacordo. De modo geral, os impactos sobre a qualidade dos recursos hidricos foram de baixa intensidade e de curta duracao. Os resultados desta pesquisa demonstraram que as medidas adotadas pela empresa responsavel pelo empreendimento florestal para minimizacao dos impactos ambientais na etapa de remocao das especies exoticas da Area de Preservacao Permanente, foram eficientes e podem ser adotadas em outras microbacias que necessitem recuperar as areas de preservacao permanente com plantios irregulares.

Abstract: This aim of this study is to evaluate the influence of water quality on the recovery of Pinus taeda plantations in the Permanent Preserved Areas in the Campinas river watershed, in the city of Joinville, Santa Catarina, Brazil. Four experimental watersheds were monitored, 3 of which consisted of pine plantations, and one with native forest, as the control, in addition to two monitoring points on the Campinas river, one upstream and one downstream from the reforestation. The following parameters were used to monitor the water quality: water temperature, pH, electrical conductivity (EC), dissolved oxygen (DO), biochemical oxygen demand (BOD), turbidity (TB), total dissolved solids (TDS), total suspended solids (TSS), total nitrogen (TN), nitrate (N-NO3 -), total phosphorus (P) and potassium (K), as water flow (Q) and rainfall indices from February 2007 to June 2011. The harvesting of the pine plantations in Permanent Preserved Areas began in June 2008. Land use was mapped for the period before and after harvesting, quantifying and spatializing the changes in vegetation cover between the two periods. Factorial analysis was applied to identify which water quality parameters suffered the greatest variations during the monitoring and to recognize the behavior pattern of the variables in response to changes in land use. Increases in temperature, pH, turbidity, total suspended solids and total phosphorus and a decrease in dissolved oxygen concentration were observed after pine harvesting in riparian zones. However, the water quality parameters were maintained in accordance with standards established by CONAMA Resolution 357/05 during most of the monitoring period, with individual events in which the turbidity, BOD and total phosphorus were in discordance with the same Resolution. In general, the impacts on the water quality were of low intensity and short duration. These results demonstrated that the measures adopted by the company responsible for the forest enterprise to minimize environmental impacts in the stage of removing exotic species from Permanent Preserved Areas were efficient and can be used in other watersheds that need to recover the permanent preserved areas with irregular plantations.