Abstract
Itapaji Reservoir serves for municipal water use, artisanal fishing, agricultural uses, and domestic activities. This study was carried out to investigate physico-chemical parameters of the reservoir to provide information for its sustainable management. Surface water samples were collected monthly from April, 2013 to March, 2015 at five purposively selected stations along the reservoir. Water temperature and transparency were measured in situ.Total Suspended Solid (TSS), Total Solid (TS), Phosphate and heavy metals were determined according to APHA methods. Data were analyzed using descriptive statistics, student’s t-test, ANOVA, and Principal Component Analysis (PCA) at α0.05. Water temperature was 27.5±0.1 ºC; Transparency, 1.5±0.1 m; TSS, 16.6± 0.7 mg/L; TS, 59.7±2.6 mg/L; phosphate, 7.2±0.5 mg/L; zinc, 1.3±0.1 mg/L; copper, 0.9±0.8mg/L; iron, 10.9±0.6 mg/L; lead, 0.1±0.007mg/L and chromium, 0.2±0.02 mg/L. phosphate, TSS, zinc, copper, iron, lead, and chromium exceeded NESREA limits for aquatic life (3.5, 0.25, 0.01, 0.001, 0.05, 0.01, and 0.001 mg/L, respectively), while copper and iron exceeded the WHO standard limit for drinking water (≤0.50, and 0.3 respectively). Transparency, TSS, zinc, copper, iron, lead and chromium had significant seasonal variations while Sodium, magnesium and chromium showed significant spatial variation. The PCA showed high positive loadings for phosphate (0.9), transparency (0.9), TS (0.882), and high negative loading for potassium(-0.730). The total suspended solid, phosphate, and some heavy metals that exceeded the recommended standard for aquatic life and drinking water revealed that Itapaji Reservoir is under pollution stress; hence the need for adequate management.
Key Words: Physico-chemical parameters, Spatial variation, Itapaji Reservoir, Pollution stress
Comments: no replies