90 likes | 348 Views
Turbidity. Measure of relative sample clarity How much light is scattered by suspended particles. Turbidity Measurements. Slow-moving, deep waters Secchi disk Rule of Thumb: light penetrates 2-3x Secchi depth. Turbidity Measurements. Fast-moving, shallow water Turbidimeter (Nephelometer)
E N D
Turbidity • Measure of relative sample clarity • How much light is scattered by suspended particles
Turbidity Measurements • Slow-moving, deep waters • Secchi disk • Rule of Thumb: light penetrates 2-3x Secchi depth
Turbidity Measurements • Fast-moving, shallow water • Turbidimeter (Nephelometer) • Nephelometric Turbidity Units (NTU’s)
NC Waters • Average NTU’s • Salt ~ 25 • Fresh ~ 50 • Trout Water ~ 10 http://h2o.enr.state.nc.us/
Factors Affecting Turbidity • High Flow Rate • Soil Erosion • Urban Runoff • Wastewater & Septic System Effluent • Decaying plants & animals • Bottom feeding fish • Algal blooms • Flooding
Before After Millipore Vacuum Filtration Apparatus
Sample # Filter # Tare Gross Net Corrected Net Liters Filtered TSS [mg/L] 1 2 3 4 Blank 1 6 Blank 2 7 Blank 3 8 Avg. blank change Blank Correction Example Data Table: