module 4 stream ecology laboratory l.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Module 4 Stream Ecology Laboratory PowerPoint Presentation
Download Presentation
Module 4 Stream Ecology Laboratory

Loading in 2 Seconds...

play fullscreen
1 / 19

Module 4 Stream Ecology Laboratory - PowerPoint PPT Presentation


  • 123 Views
  • Uploaded on

Module 4 Stream Ecology Laboratory. Solids TSS and Turbidity. Total Suspended Solids. Sediment plume off the south shore of Lake Superior. Total Suspended Solids. SAMPLING CONCERNS : collect from undisturbed water when standing in a stream, reach upstream into the current for the sample.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Module 4 Stream Ecology Laboratory' - chloris


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
module 4 stream ecology laboratory

Module 4 Stream Ecology Laboratory

SolidsTSS and Turbidity

slide2

Total Suspended Solids

Sediment plume off the south shore of Lake Superior

total suspended solids
Total Suspended Solids

SAMPLING CONCERNS:

  • collect from undisturbed water
  • when standing in a stream, reach upstream into the current for the sample

In lakes, boat propeller action also may disrupt sediments in shallow areas

avoid sampling from temporarily disrupted area

slide4

Total Suspended Solids

TSS, as well as turbidity and any other parameter dominated by the particulate fraction, can be very patchy - it may be wise to composite from a number of spots within the site’s area

slide5

Total Suspended Solids

Figure 1

- filter a known amount of water through a pre-washed, pre-dried at 103-105 oC, pre-weighed (~ + 0.5 mg) filter

- rinse, dry and reweigh to calculate TSS in mg/L 

- possibly save the filters for other analyses such as volatile suspended solids (VSS) that estimates organic matter

total suspended solids8
Total Suspended Solids

Analytical balance

Drying oven

Filter and petri dish

slide9

TSS – Methodology

Calculate TSS by using the equation below

TSS (mg/L) = ([A-B]*1000)/C

where

A = final dried weight of the filter (in milligrams = mg)

B = Initial weight of the filter (in milligrams = mg)

C = Volume of water filtered (in Liters)

how does turbidity relate to tss
How does Turbidity relate to TSS ?

A general rule of thumb:

1 mgTSS/L ~ 1.0 - 1.5 NTU’s of turbidity

BUT – Turbidity scattering depends on particle size so this is only a rough approximation

slide11

Turbidity-Transparency Tube

(for streams, ponds, wetlands, some coastal zones)

May have stopper and valve

slide12

Turbidity-Transparency Tube

  • Analogous to secchi depth in lakes: a measure of the dissolved and particulate material in the water
  • Useful for shallow water bodies where a secchi would still be visible on the bottom or fast moving streams
  • Best for clearwater bodies of water (not stained with dissolved organic compounds from bogs) but not tooclear water
  • It is a good measure of turbidity and suspended sediment (TSS)
  • Used in many volunteer stream monitoring programs

Image: http://www.watermonitoringequip.com/

how does turbidity relate to tss13
How does Turbidity relate to TSS ?

A general rule of thumb:

1 mgTSS/L ~ 1.0 - 1.5 NTU’s of turbidity

BUT – Turbidity scattering depends on particle size so this is only a rough approximation

field profiles turbidity

Even small amounts of wave action can erode exposed lakeshore sediments, in this case a minepit lake from northeastern Minnesota. Guess the mineral mined here.

Field Profiles-Turbidity
  • Turbidity measures the scattering effect suspended particles have on light
    • inorganics like clay and silt
    • organic material, both fine and colored
    • plankton and other microscopic organisms
  • Field turbidity measurements are made with
    • turbidimeters (bench meter for discrete samples)
    • Submersible turbidity sensors (Note - USGS currently considers this a qualitative method)
    • Transparency or turbidity tubes
turbidimeters nephelometric optics

http://www.bradwoods.org/eagles/turbidity.htm

Turbidimeters -Nephelometric optics

Principle:

  • nephelometric turbidity estimated by the scattering effect suspended particles have on light
  • detector is at 90o from the light source

Units:

  • Nephelometric Turbidity Units (NTU)
  • standards are formazin or other certified material
  • JTU’s are from an “older” technology in which a candle flame was viewed through a tube of water
  • 1 NTU = 1 JTU (Jackson Turbidity Unit)
bench vs submersible turbidimeters

1. Portable

Bench vs Submersible Turbidimeters

Discrete depth - collect water sample and analyze water in Lab

vs

Continuous profile using submersible sensor

YSI 6820 with unwiped turbidity

YSI wiping turbidity

Hydrolab

field profiles turbidity17
Field profiles-turbidity

Sensor calibration

  • Turbidity free water = zero (0 NTU) standard
    • USGS recommends filtering either sample water or deionized water through a 0.2 um or smaller filter to remove particles
    • WOW uses deionized water that is degassed by sparging (bubbling) with helium to minimize air bubbles that give false turbidity readings
  • Standards range depends on anticipated sample values
    • lakes - typically 0-20 NTU
    • streams and wetlands - 0-20, 0-50 or 0-100 NTU
    • 2 non-zero standards typically adequate (response is linear)
    • formazin particles (either from a “recipe” or purchase a certified, concentrated stock solution (usually 4000 NTU)
    • other commercially available materials - polystyrene
    • need to worry about storage limits - Primary stock of 400 NTU’s lasts < 1 month when refrigerated. Dilute working standards from intermediate stock solution daily.
field profiles turbidity calibration standards prep

Source

Concentrations

Suggested holding times

Hach Company

2 to 20 NTU

Prepare daily

20 to 40 NTU

Prepare monthly

Standard Methods

All dilutions

Prepare daily

EPA Region 5

All dilutions

Prepare weekly

Field profiles-turbidity - calibration standards prep
field probes turbidity
Field Probes-turbidity
  • Comparability of different methods:
    • With the proliferation of automated in situ turbidity sensors there is concern about the comparability of measurements taken using very different optical geometries, light sources and light sensors.
    • The US Geological Survey and US Environmental Protection Agency are currently (August 2002) developing testing procedures for a field comparison of a number of instruments produced by different manufacturers. We will include these results when they become available.
  • Standard Methods refers to :

APHA.1998. Standard methods for the examination of water and wastewater. American Public Health Association, Washington, D.C.