TTWG Report & Technical Topics
SRRTTF Meeting
Dave Dilks
June 1, 2016
Items
• Magnitude of Source Areas and Pathways memo
– Proposed format for displaying WWTP data
• 2016 Monthly Monitoring
– Deferral of June event to fall?
• Homolog analysis
– Implications for Comprehensive Plan
• Cost/Effectiveness of PCB Control Actions
– Overview/implications for workshop
Table 4: Magnitude of Source Areas
• Current draft table summarizes a lot of information
PCB Concentration (pg/l)
Synoptic Survey
Routine Monitoring
3x correction
10x* correction
Industrial
Kaiser
Inland Empire Paper
Municipal
City of Spokane
Spokane County
Coeur d’Alene
Post Falls
Liberty Lake
HARSB
Total
Flow (cfs)
Load (mg/day)
3264
3180
2232*
2223
13.0 -13.25
10.8
70 – 105
58.9 – 84.3
975
361
533
213
219
-
729
30
67
44. 1 – 48.9
11.5
87.2 – 105
0.87 – 10.4
0.85 – 6.97
163
241
108
3.88 – 3.89
1.12
0 – 1.71
5.19 – 5.35
1.55 – 2.03
0.60 – 0.68
0.0 – 0.45
220 – 315
• Request from last Task Force meeting to separate
Synoptic Survey and Routine Monitoring results
Proposed Format for Table 4
• Synoptic Survey results
Location
Industrial
Kaiser
Inland Empire Paper
Municipal
City of Spokane
Spokane County
Couer d'Alene
Post Falls
Liberty lake
HARSB
Total
Samples
Sample Type
Synoptic Survey
PCB Concentration (pg/L)
(3x Blank Correction)
Minimum
Maximum
Synoptic Survey
Load (mg/day)
(3x Blank Correction)
Minimum Maximum
4
5
Grab
Grab
2,500
2,600
4,600
3,600
80
69
150
95
5
5
4
4
4
0
Grab
Grab
Grab
Grab
Grab
Grab
770
270
530
180
190
-
23,000
490
1,200
220
260
-
83
8
7
2
0.5
2480
14
16
2
0.7
250
2800
Proposed Format for Table 4 – Part 2
• Routine Monitoring
Location
Industrial
Kaiser
Inland Empire Paper
Municipal
City of Spokane
Spokane County
Couer d'Alene
Post Falls
Liberty lake
HARSB
Total
Samples
Sample Type
52
24-hr Composite
Routine Monitoring
PCB Concentration (pg/L)
(3x Blank Correction)
Minimum
Maximum
Routine Monitoring
PCB Concentration (pg/L)
(10x Blank Correction)
Minimum Maximum
Routine Monitoring
Load (mg/day)
(3x Blank Correction)
Minimum Maximum
Routine Monitoring
Load (mg/day)
(10x Blank Correction)
Minimum
Maximum
• Still awaiting raw data from many of you to
allow us to calculate 3x values
– Finalization of memo requires this data
2016 Monthly Sampling Update
• March through May sampling completed
– No PCB results received yet
– Laboratory error with March samples, archive samples
being analyzed
– One incorrect sampling location in April
• Barker Rd. sampled instead of Trent
• Is June sampling worthwhile?
– “make a determination of whether sampling in June of
2016 will be worthwhile in terms of capturing the
effects of snowmelt”
Remaining Snow Pack
• 61% of median year snow pack remains
• Normal precipitation
– Much of the snow pack lost due to early snowmelt
Flows in Lake Coeur d’Alene Tribs
• Higher than normal flows in February – April
– Below average now
• Recommend deferring June sampling
What Were Conditions During Events?
What Were Conditions During Events?
• March and May events two days after significant
rainfall
– High flows (1500 cfs) in Latah Creek during March event
Homolog Mass Balance Assessment
• Mass balance assessments conducted for Task
Force have been conducted on total PCBs
– Concluded presence of significant groundwater load
entering between Mirabeau Park and Trent Ave
• Spokane County has recently conducted similar
analyses looking at individual homologs
– Findings consistent with those for total PCBs
between Mirabeau Park and Trent
– Interesting results downstream of Trent
Preliminary County Findings
Trent to Green Section
• Large loss in di- through tetra- homologs
• Large gain in penta- through hepta- homologs
Ramifications to Comprehensive Plan
• No change regarding originally identified load
• Identifies potential presence of new load
– Groundwater loading in other reaches have been
identified as uncertain
– Homolog analysis raises the threat level, but likely won’t
affect selected 2016 Control Actions
• Next steps
– Definitely merits further examination
– Prime candidate for Future Studies section of Comp Plan
– Include in 2015 report?
Cost/Effectiveness of Control Actions
• First draft coming out today
• Lots of information
• Lots of opportunity for input
Cost/Effectiveness of Control Actions
• Naïve initial impression/hypothetical example
Cost/Effectiveness of Control Actions
• Naïve initial impression/hypothetical example
Cost/Effectiveness of Control Actions
• Naïve initial impression/hypothetical example
Cost/Effectiveness of Control Actions
• Complications
• Incomplete information on costs and
effectiveness from existing studies
• Uncertain magnitudes of transport pathways
and delivery mechanisms
• Memo currently shows magnitudes of sources
and pathways for each source area, and which
Control Action(s) apply
Legacy Fixed Building Sources
Legacy Non-Fixed Building Sources
Legacy Surface Soils
Industrial Equipment
Cost/Effectiveness of Control Actions
• Complications (good)
– Many Control Actions already being implemented
• WWTPs
– Upgrades required for DO TMDL
– Toxics Management Action Plans
• Stormwater
– City of Spokane’s Integrated Clean Water Plan
– Most other stormwater is being diverted to groundwater – this is
considered a Control Action in most places
• MTCA clean-up
Selection of Control Actions
• Potential Selection Criteria
– Affects qualitatively significant pathways
– Qualitatively cost effective
– Has a responsible party capable of implementation
– High on the pyramid
• Don’t make it > Don’t use it > Use less of it > Manage it
properly > Dispose of it properly > Treat it
Selection of Control Actions
• Other Potential Selection Criteria
– Leverages or supports existing Control Actions
– Provides ancillary benefits
– Addresses a pathway not currently covered by
existing Control Actions
Cost/Effectiveness of Control Actions
• Official Schedule
– Final draft due July 14
• Proposed Interim Schedule
– Initial comments requested by June 15 (or earlier)
– Second draft provided by June 22
– Official review draft by July 6