Atmospheric Deposition Project - Sample Collection Protocol (updated July 2009)

Supplies:

• Buckets (weighed, bagged and labeled)
• Lids (weighed, bagged and labeled)
• 12V battery (w/ thumbscrews)
• Backpack with field datasheets and instructions, cleaning cloths/sponges, sandpaper, wire brush and/or water bottle, screwdriver, mineral oil, and Vaseline

Field Procedure/Sampling Schedule:

1. Dry buckets are changed monthly, all on the same day (3rd Tuesday of each month).
2. Wet buckets are collected/changed according to the following rules:

• Collect a sample after EVERY "significant" rainfall event at EVERY site where it rained (≥0.25" rain in 24 hour period)
• IF THIS NOT POSSIBLE AND 30% or greater chance of more rain, collect the day after
• OR COLLECT WITHIN 48 hrs of end of significant rainfall (DO NOT let wet samples ≥0.25" sit for >48 hrs IF POSSIBLE)
• If in doubt – preference is for sample to be prepped and wait in cold room for analysis rather than sitting in bucket out in field waiting to be collected.

Be careful not to contaminate the old or new bucket. If the sample is spilled or bucket dropped at any time, especially if the rim of the bucket or lid contacts any surfaces, make a note.

Changing the wet side bucket:

1. To ensure the collector is working properly, short out the sensor with a few drops of water or the wire brush and watch the roof to see if it moves freely and evenly with little motor noise. The lid seal pad should rest snugly on the dry side bucket. See troubleshooting section below if there is a problem.
2. Examine the wet side bucket carefully for contamination such as soil, insects, bird droppings, etc. Record signs of contamination on the datasheet.
3. Using the bag the lid is in as a glove, place the lid on the wet side bucket.
4. Remove the bucket and lid from the collector, and snap the lid on tightly.
5. On the datasheet record initials, time, date, amount of rain in rain gauge, lid label and weight, old bucket label and weight, new bucket label, and contaminants.
6. After recording the amount of rain, empty the contents of the rain gauge and refill with mineral oil to a depth of about 1 mm.
7. While the roof is still covering the dry side bucket, wipe the top of the roof, sensor, and around the buckets to remove bird droppings, dirt, etc. that could contaminate the sample bucket.
8. Using the bag as a glove, place the new wet side bucket in the bucket holder.
9. Blow off any excess water on the sensor, waiting until the roof moves back to the wet side.
10. Place the securely closed bucket into the bag the clean bucket was in.

Changing the dry side bucket:

1. Examine the dry side bucket carefully for contamination such as soil, insects, bird droppings, etc. Record signs of contamination on the datasheet.
2. Using the bag the lid is in as a glove, place the lid on the dry side bucket.
3. Remove the bucket and lid from the collector, and snap the lid on tightly.
4. On the datasheet record initials, time, date, lid label, old bucket label, new bucket label, and contaminants.
5. Disconnect the battery at the screw terminals and replace with charged one (LDS only).
6. To ensure the collector is working properly, short out the sensor with a few drops of water or the wire brush and watch the roof to see if it moves freely and evenly with little motor noise. See troubleshooting section below if there is a problem.
7. Blow off any excess water on the sensor, waiting until the roof moves back to the wet side.
8. Before replacing the dry bucket and with the roof covering the wet side bucket, wipe the top of the roof, sensor, and around the buckets to remove bird droppings, dirt, etc. that could contaminate the sample bucket.
9. Using the bag as a glove, place the new dry side bucket in the bucket holder.
10. Place the securely closed bucket into the bag the clean bucket was in.
11. Check the rain gauge and refill with mineral oil to a depth of about 1 mm if necessary.

Changing Both Buckets:

1. To ensure the collector is working properly, short out the sensor with a few drops of water or the wire brush and watch the roof to see if it moves freely and evenly with little motor noise. The lid seal pad should rest snugly on the dry side bucket. See troubleshooting section below if there is a problem.
2. Examine the wet side bucket carefully for contamination such as soil, insects, bird droppings, etc. Record signs of contamination on the datasheet.
3. Using the bag the lid is in as a glove, place the lid on the wet side bucket.
4. Remove the bucket and lid from the collector, and snap the lid on tightly.
5. On the datasheet record initials, time, date, amount of rain in rain gauge, lid label and weight, old wet bucket label and weight, new wet bucket label, and contaminants.
6. After recording the amount of rain, empty the contents of the rain gauge and refill with mineral oil to a depth of about 1 mm.
7. Blow off any excess water on the sensor, waiting until the roof moves back to the wet side.
8. Examine the dry side bucket carefully for contamination such as soil, insects, bird droppings, etc. Record signs of contamination on the datasheet.
9. Using the bag the lid is in as a glove, place the lid on the dry side bucket.
10. Remove the bucket and lid from the collector, and snap the lid on tightly.
11. On the datasheet record the lid label, old dry bucket label, new dry bucket label, and contaminants.
12. Now that both buckets have been removed, wipe the top of the roof, sensor, and around the buckets to remove bird droppings, dirt, etc. that could contaminate the sample buckets.
13. Using the bag as a glove, place the new dry side bucket in the bucket holder.
14. Again, short out the sensor with a few drops of water or wire brush and then using the bag as a glove, place the new wet side bucket in the bucket holder.
15. Blow off any excess water on the sensor, waiting until the roof moves back to the wet side.
16. Place the securely closed buckets into the bags the clean buckets were in.

If the sensor, motor, or battery is not working and the roof has stuck allowing water in the dry or both sides, pour all sample into the dry bucket, record on the field sheet that this is a "bulk" sample (i.e. wet and dry deposition combined), and then put the collector in "bulk" sample mode. If the collector motor box will not move the lid, reach under the main frame of the collector and push the clutch arm counter-clockwise. The clutch will disengage and the lid mechanism will be free of the drive system. Manually position the lid over the dry side bucket and use the bucket retaining springs to secure the lid. Disconnect the collector from the power supply.

Troubleshooting Tips for ADP Collector

If collector fails to operate, try the following:

1. Check power source. Battery: Check for corrosion of battery cable connections at battery and at motor. Many times the connectors at the battery become corroded, resulting in a bad connection. Sanding the connectors clean will solve this problem. Check battery voltage, battery may be dead. If the connectors at the motor are the problem, sand clean, apply Vaseline and reconnect. AC: Check if plug is connected and check for cuts or gashes in the power cord which may be causing a short.
2. Check wet sensor. Replace with a spare and see if collector operates. If not, then the motor is bad and must be replaced. A faulty motor box is usually indicated by one of four things:

• Upon a "wet" sense the roof cycles continuously back and forth.
• Upon a "dry" sense, the roof cycles continuously back and forth.
• The motor does not run at all, even when the crank arm is placed in a vertical position by hand.
• The temperature of the sensor plate is HOT when the collector is in the "dry" collection state.

All of these conditions require that one of the mercury wetted switches within the motor box be replaced. The motor box can be removed as a unit by removing the four large screws from the top of the collector. It can then be shipped to the manufacturer at the following address: Aerochem Metrics, Inc., 4473 W. Hwy. 476. Bushnell, FL 33513. Ph: (352) 793-8000, Fax: (352) 793-3954.

Atmospheric Deposition Project - Sample Processing Protocol (updated July 2009)

1. Upon returning from the field, remove buckets from plastic bags and wipe any soil/debris off the top, bottom and sides of each bucket.
2. When necessary buckets can be left in the cold room overnight. Wet buckets must be allowed to acclimate at room temperature for 2-4 hours before weighing.

Dry Collection:

1. Wearing nitrile gloves, open each dry bucket and remove any contamination (insects, bird droppings, etc.) with HCl-washed and nanopure-rinsed forceps. Ensure contaminants are noted on the field datasheet.
2. Using a nanopure-rinsed 500 ml graduated cylinder, add 500 ml of nanopure water to the bucket.
3. With the lid off, swirl the water around the inside of the bucket as high as possible without any risk of spillage. Rest the lid loosely on top of the bucket (do not push lid down).
4. Place each bucket on the orbital shaker for 10 minutes.
5. Rinse a 500 ml plastic HCl bottle with a small amount of sample (~5-10 ml), and then pour the remaining sample from the bucket into the bottle. Record the HCl bottle number on the datasheet.
6. Replace the lid on the bucket and set aside to be cleaned.
7. For ammonium (NH4-N) and nitrate (NO3-N) analysis: (1) Label an ammonium centrifuge tube with "ADP", "site-D" (for dry collection; "site-W" for wet), and date; (2) Rinse the tube with a small amount of sample and then fill and cap; (3) Centrifuge at 8000 rpm for 12 minutes (make sure rotor is balanced); (4) Place the tubes in a tube rack labeled with the date and "ADP N" on a strip of lab tape, then store the tubes in the freezer in GWC 639 (prep lab) until they can be run with WMP samples.
8. For Dissolved Organic Carbon (DOC) analysis: (1) Using a clean, nanopure-rinsed 25 mm filter apparatus with an ashed GF/F 25 mm filter, filter a small amount of sample (~10 ml) to rinse and then discard; (2) Filter ~30 ml of sample; (3) Record the DOC vial number on the datasheet; (4) Rinse the vial with ~3 ml of the filtered sample. Discard the rinse and then fill the DOC vial with the remaining filtrate; (5) Rinse the filter apparatus with nanopure before beginning the next sample; (6) Acidify each sample with 1 drop of concentrated HCl; (7) Place the samples in a tube rack labeled with the date and "ADP DOC—Acidified" on a strip of tape, then store the tubes in cold room in GWC 675 until the samples can be run (preferably within 24 hours).
9. For anion and cation analysis: (1) Label two sterile 50 ml Falcon tubes with "ADP", "site-D" (for dry collection; "site-W" for wet), and "anions" or "cations" (one of each); (2) Using a clean, nanopure-rinsed 47 mm filter apparatus with a Supor-450 47mm membrane filter, filter a small amount of sample (~15 ml) to rinse and then discard; (3) Filter enough of the remaining sample to rinse and fill the two 50 ml Falcon tubes; (4) Rinse the anion tube with ~5 ml filtrate, discard the rinse, and then fill and cap; (5) Repeat with cation tube; (6) Rinse the filter apparatus with nanopure before beginning the next sample; (7) Place the anion samples in a Styrofoam tube holder labeled with the date and "ADP Anions" on a strip of tape, then store the tubes in cold room in GWC 675 until samples can be run (preferably within 24-48 hours of collection for reactive species); (8) Place the cation samples in a Styrofoam tube holder labeled with the date and "ADP Cations—Acidified" on a strip of tape and then acidify the cation samples as follows: (a) Place an empty 50 ml Falcon tube on the balance and tare; (b) Weigh the cation Falcon tube on the tared balance and record the sample weight (in grams) on the datasheet; (c) Multiply the weight by 7.144. The result equals the amount (in microliters) of ultrapure HNO3 to add. Record this volume on the datasheet; (d) Under the hood, use the adjustable pipette designated for acids to add the acid to the samples; (e) Once acidified, the samples are stored on the shelf in the storage room in GWC 681.

Wet Collection:

Notes:

• If there is less than ~10ml of sample in the wet bucket, note this on the datasheet and do not process the sample. If the sample bottle volume is limited (i.e. 10<140 ml) or lost, strike the unprocessed subsamples on the datasheet.
• In cases when there is not enough rain to complete all of the analyses, the sampling priority is as follows: Ammonium/nitrate, DOC, Anions, Cations, pH.

1. Remove the wet collection bucket from the plastic bag and wipe any soil/debris off the top, bottom and sides of each bucket.
2. Tare the 12 kg balance in GWC 681 and weigh each bucket.
3. Record the total weight (in kilograms) on the datasheet. Subtract the lid and bucket weights from the total weight and record the net sample weight (in grams) on the datasheet.
4. Perform steps 5-9 of the above dry collection protocol.
5. After step 9 of the dry collection protocol, measure the pH of the sample remaining in the 500 ml HCl bottle using the pH meter in GWC 677 and record on the datasheet.

Lab cleanup:

1. Rinse, dry, and HCl-wash any glassware used.
2. Clean buckets and lids according to the "Bucket cleaning, bagging and prep" protocol
3. Ensure an adequate supply of ashed 25mm GF/F filters (4 hours in muffle furnace at 500 degrees). Filters can be removed from the furnace the following day.

Note: Bulk Samples if dry buckets have collected rain water due to a collector malfunction, process this water as a bulk sample (see ADP Sample Collection Protocol). Add the water from the wet bucket to the dry bucket, then weigh and process as a wet bucket EXCEPT swirl the sample as you would a dry bucket before proceeding.

Chemical water analysis

Samples for the analyses of most nitrogen species (NO3D_LACHAT, NH4_LACHAT, NH4_TRAACS) were centrifuged at 8000 rpm for 12 minutes before analysis on a Lachat QC80000 or TrAAcs auto analyzer. Total nitrate (NO3T_TOC_TN) samples as analyzed on a Shimadzu TOC-VC/TN analyzer were filtered through pre-combusted 0.7-μm Whatman glass fiber filters (GF-F). Most phosphorus species (PO4T_LACHAT, PO4D_LACHAT, PO4D_TRAACS) were centrifuged at 8000 rpm for 12 minutes or filtered through PALL 47mm 0.45-μm membrane filters before analysis on a Lachat QC80000 or TrAAcs auto analyzer. Samples for the analysis of Dissolved Organic Carbon (DOC) were filtered through pre-combusted 0.7-μm Whatman glass fiber filters (GF-F) before analysis on a Shimadzu TOC-VC/TN analyzer. Samples for the analyses of most anions and cations (CaD_FLAME_AA, KD_FLAME_AA, MgD_FLAME_AA, NaD_FLAME_AA, MoD_ICPMS, CaD_ICP, KD_ICP, MgD_ICP, NaD_ICP, CaD_ICPMS, KD_ICPMS, MgD_ICPMS, NaD_ICPMS) were filtered through PALL 47mm 0.45-μm membrane filters before analysis on a flame atomic-absorption spectrometer or by inductively coupled plasma. Samples for the analysis of sulfate by ion chromatography (SO4D_IC) were filtered through pre-combusted 0.7-μm Whatman glass fiber filters (GF-F). For detailed protocols of chemical analyses, please see: http://www.asu.edu/gel.