Dissolved Oxygen Study Manual

Table of Contents

Introduction 3

Safety Precautions 7

Analytical Techniques 8

Procedure 9

Data Sheet 15

Volunteer Schedule 17

Appendix A: Maps A-1

Appendix B: Fact Sheet B-1

1

Welcome Citizen Scientist Volunteers to the 2011

Harpeth River Dissolved Oxygen Study.

Forward

Your participation in this project is vital; without your help there is no way we could collect

data from over 90 miles of the Harpeth River. The data that we collect tell a very compelling story

of the health of the river as well as what and where impact sources happen along the river. Various

agencies and enterprises, from agriculture to municipal waste, point the finger at other players as

the cause of impairments in the Harpeth River, but our dissolved oxygen (DO) study illustrates that

all the players contribute in some way. This study helps us make the case that they all must be part

of the solution. The data that we collect and present will be viewed by USEPA, Tennessee

Department of Environment and Conservation (TDEC), USDA and Tennessee Department of

Agriculture (TDA), The City of Franklin and their Integrated Water Resources Plan (IWRP), which is

still developing, along with other county and municipal governments, especially those with

stormwater regulatory obligations.

Overview

This year we will take data at 14 sites from Eagleville in the headwaters to the Harris-Street

Bridge just 22.8 miles from the Cumberland River. The data will be diurnal in nature, meaning

around the clock, and we will collect data in approximately the same timeframe all along the river.

Thus, we are comparing apples to apples in terms of external conditions like weather. The diurnal

data give us the variation in DO from daylight, when plants and algae are converting dissolved CO2

into O2 through photosynthesis, and nighttime, when plants, algae, bacteria and aquatic animals are

converting O2 into CO2 through respiration. The magnitude of the swings (i.e. the difference

between the highs and the lows), as well as the actual low values recorded, tell us volumes about

what is occurring in the water and give us strong clues as to the types and sources of impacts for

any given location. Taken together these data give us a very good picture of what is going on along

the length of the river. They help everyone involved understand where and why these impacts

need to be addressed in addition to helping with the planning and installation of Best Management

Practices (BMPs).

3

The approach we are taking is to build teams for each site, or groups of sites, so that all time slots

get covered without undue hardship on anyone. It is extremely important that we get all the data; if

any site has anomalies or weather changes greatly (i.e. lots of rain) we can see what happens in

adjoining sites. All teams should start collecting data four times in a twenty-four hour period

sometime between Friday afternoon, September 9th, and Sunday morning, September 11th, so all

data are complete no later than 6 am Monday morning, September 12th. The time slot with which

you begin is not crucial, but it is essential that once you begin all four sample data are

collected for that twenty-four hours. The next collection period will begin Tuesday morning,

September 13th, and all data needs to be in by Thursday morning, September 15th. The final

collection period will begin Friday afternoon, September 16th with all data collected by Monday

morning, September 19th.

Procedures

All teams will be issued one or more LaMotte Dissolved Oxygen Kits (code 5860) for the

duration of the study. Each time the team members go to collect data, the following procedure

needs to be run three times, and the results recorded for each. Temperature, pH, and other

parameters need only be recorded once for each visit to the river. The water sample bottle must be

rinsed three times with the river water that you are about to test before collecting the sample and

should be rinsed at least once at the completion of the three samples. Likewise, the reaction tube

should be rinsed three times with a small amount of the reacted (yellow) sample before filling for

the titration phase of this test.

The collection of data will begin by filling a water sampling bottle with water from the river

and capping underwater to ensure no air bubbles. Then, begin adding reagents (see procedures).

Set the bottle on a flat surface and uncap. Quickly add five drops each of Alkaline Potassium Iodide

Azide and Manganous Sulfate (in either order). Recap the bottle, being careful to not get any air

bubbles in it. Invert the bottle several times and let sit for a minute (you will notice a cloudy

whitish reaction). Next, open the bottle and add 5 drops of 1:1 Sulfuric Acid (while this is diluted,

care should still be taken, rinse with water immediately if any gets on you). Recap, once again being

careful to not introduce air bubbles, and invert several times. This reaction will turn the sample

yellow with red precipitate. At this time, the O2 is fixed, and oxygen in the atmosphere will no

longer affect the measurement.

4

Once the precipitate has mostly settled, the reaction tube should be rinsed 3 times with the

sample and then filled to the 20 ml line (with the bottom of the meniscus at the line). At this point it

is OK to add 5 drops of the Starch Indicator, turning the yellow sample indigo. Cap and invert a few

times (make sure your finger is over the hole in the cap). If you look closely at the plunger in the

syringe included with the kit, you will see that it has a seal near the “needle” end, and that when

completely compressed, the lower part of the seal (away from the “needle”) is on 10. This is from

where we measure. Fill the syringe with Sodium Thiosulfate 0.025 N to the 0 line, taking care that

no air is entrained in the syringe. Insert the “needle” into the hole in the cap of the reaction tube,

and add a small amount of Thiosulfate until the sample begins to lighten, shaking between

additions. At this point, add very small amounts (one drop or less) each time and shake. When the

sample turns completely clear and remains that way for several seconds, read the syringe and

record. This must be repeated twice more, so there are three results to report for each trip (event)

to the river.

Other data that are collected and recorded for each event are air temperature and water

temperature (o C), pH (using color comparison chart), date, time (24 hour, example-1200 for noon,

1800 for 6 pm) upon completion of the event, and any weather observations (like light rain,

overcast, sunny, etc.). Once an event is completed and the data recorded on the data sheet included

in this manual, please go to www.harpethriver.org/volunteer/2011_DO_data and post the results

so they can be compiled electronically as we go. Once all data are collected, we will need the hard

copy of the data sheets returned for future reference and possible auditing of our data for

validation purposes.

5

7

8

9

10

11

12

13

Dissolved Oxygen Field data Sheet

Site #

LAT LON Decimal Lat Decimal Lon

0.0000 0.0000

Event # date time temp pH result

1 result

2 result

3 result avg Weather Data collected by:

EXAMPLE 9/5/08 6:30 24.5 7 5.3 5.1 6 5.47 light rain

6am

Noon

6pm

Midnight

15

Event # date time temp pH result

1 result

2 result

3 result avg Weather Data collected by:

6am

Noon

6pm

Midnight

6am

Noon

6pm

Midnight

DO Procedure: 1. Collect sample from mid-stream if possible and at mid depth 2. Fill DO bottle completely and cap under water, making sure there are no air bubbles 3. Add 8 drops Alkiline potassium iodide azide-iodide 4. Add 8 drops Manganous sulfate, shake and let settle 5. Add 8 drops sulfuric acid, shake and let settle 6. Pour 20 ml into titrator tube 7. Add 8 drops Starch Indicator (dark blue color) 8. Fill titrator syringe to mark with Thiosufate, begin adding to titrator tube until clear 9. Read titrator syringe and record (note: if the solution does not become clear refill syringe and add 10 ml to results)

16

2011 Harpeth River Dissolved Oxygen Study Site Volunteer Schedule

Location: ________________________________________________________________

Day 1

Volunteer name Date Time

Event 1

Event 2

Event 3

Event 4

Day 2

Volunteer name Date Time

Event 1

Event 2

Event 3

Event 4

Day 3

Volunteer name Date Time

Event 1

Event 2

Event 3

Event 4

17

Appendices

Appendix A: Maps

Appendix B: Dissolved Oxygen Fact Sheet

A-1

Appendix A

A-2

B-1

Appendix B

B-2

B-3