Hydrochemistry of Cachoeira River (Bahia State, Brazil) Hidroqu赤mica do Rio Cachoeira (Bahia, Brasil)

作者：Maria Zita Tabosa Pinheiro de Queiroz Lima Lucio; Simone Setubal dos Santos; Daniela Mariano Lopes da Silva

来源：Acta Limnologica Brasiliensia, 2012.

• bacia hidrografica
• hidrogeoquimica
• Rio Cachoeira
• watershed
• hydrogeochemical
• Cachoeira River

AIM: The aim of this study is to evaluate the spatial-temporal changes of chemical elements in the surface waters of the Cachoeira River in order to evaluate the impacts of anthropogenic activities in water quality; METHODS: Samples were collected monthly between August 2008 and August 2009 at six collection points along the river. The abiotic parameters dissolved oxygen, pH, electrical conductivity and temperature were performed in the field using portable digital meters; concentration of ions nitrite (NO2-), nitrate (NO3-), ammonia (NH4+), phosphate (PO4-), sodium (Na+), calcium (Ca+2), potassium (K+), chloride (Cl-), magnesium (Mg+2), sulfate (SO4-2) were determined by ion chromatography and bicarbonate (HCO3-) was calculated by a model of ionic associations originated from alkalinity values; RESULTS: The spatial variations showed that anthropogenic activities and land use changes (cocoa crops and pasture) appear to be the major factors influencing the distribution of nutrients in the Cachoeira River; however, lithology seems to be the factor influencing the major ions; CONCLUSIONS: Variations in ion concentrations were directly related to drought and rainy periods, the geological formation, and the various land uses. The lack of treatment of domestic wastes and their incorrect disposal in water bodies has significantly contributed to the aggravation of environmental problems and consequently the health of the population. OBJETIVO: O objetivo do presente estudo foi avaliar as varia es espa o temporais da qu赤mica das 芍guas superficiais do Rio Cachoeira a fim de estabelecer os impactos das atividades antropog那nicas na qualidade da 芍gua; M谷TODOS: As coletas foram realizadas mensalmente entre agosto de 2008 e agosto de 2009 em seis pontos de coleta ao longo do rio. Os parametros abi車ticos oxig那nio dissolvido, pH, condutividade el谷trica e temperatura foram determinados atrav谷s de medidores port芍teis no campo; a concentra o dos 赤ons nitrito (NO2-), nitrato (NO3-), am nia (NH4+), fosfato (PO4-), s車dio (Na+), c芍lcio (Ca+2), pot芍ssio (K+), cloreto (Cl-), magn谷sio (Mg+2), sulfato (SO4-2) atrav谷s da cromatografia i nica e o bicarbonato (HCO3-) atrav谷s da alcalinidade; RESULTADOS: Os resultados referentes a varia o espacial no Rio Cachoeira demonstraram que as atividades antropog那nicas e os diferentes cultivos ao longo da bacia (cultivo de cacau e pastagem) s o os principais fatores que influenciam na distribui o dos nutrientes (N e P). No entanto, a litologia parece ser o principal respons芍vel pelas concentra es dos 赤ons maiores, n o havendo diferen as ent