Caged Clam Study
Caged Clam Study “Parks” and “Pond” Reaches, 2004 Thomas R. Benzing and Stacy Davenport James Madison University February 8, 2005
Clams taken from North River
Collecting clams (above) and sorting them by size (right)
Caging and Canoeing Clams
Clam Cage Placement Dooms Mill Pond
Hopeman
Parkway
Basic Park
North Park
Dates of Study • Caged Clams: North Park to Basic Park – Placed on July 10, 2004 – Recovered on September 25 (after 77 days) – 13 of 20 cages recovered (65%)
• Caged Clams: Dooms Mill Pond – Placed on July 16, 2004 – Recovered on September 25 (after 71 days) – 18 of 20 cages recovered (90%)
JEANNE FRANCES
Cages recovered
IVAN
Parks Reach: Mercury by Site Mercury in Caged Clams from Parks Reach
100
WWTP outfall
Oxbow
60
40
20
Average Total Hg (ppb)
Methyl Mercury
00 CB 19
C
CB 16
00
00
Site ID
C
CB 14 C
CB 13
00
00 C
CB 11 C
CB 10
00
00 C
CB 09 C
CB 08
00
00 C
CB 07 C
CB 04
00
00 C
CB 03
00 C
CB 02 C
CB 01
00
0
C
Mercury (ppb)
80
Parks Reach: Map of Mercury in Clams Hopeman Parkway North Park Basic Park
Waynesboro wastewater treatment plant
Total mercury concentrations (ppb in clams) are shown by size of red symbol and numbers near cage locations
2nd Street Oxbow Steele Run
US Route 340
Pond Reach: Mercury by Site Mercury in Caged Clams in South River in CCC Sites
220 200 180
140 120 100 80 60
in mill pond
40 20 0 C C C 00 00 C C C 02 00 C C C 03 00 C C C 04 00 C C C 05 00 C C C 06 00 C C C 07 00 C C C 08 00 C C C 09 00 C C C 10 00 C C C 11 00 C C C 12 00 C C C 13 00 C C C 14 00 C C C 16 00 C C C 17 00 C C C 18 00 C C C 19 00
Mercury (ppb)
160
Site ID Average Total Hg
Methyl Hg
Pond Reach: Map of Mercury in Clams
Total mercury concentrations (ppb in clams) are shown by size of red symbol and numbers near cage locations
Mill Pond
mill dam
US Route 340
Dooms
Conclusions from Caged Clam Study, 2004 • Mercury concentrations increase downstream from Dupont’s 001 outfall on South River in Waynesboro • Mercury concentrations increase downstream from an oxbow (Steele Run confluence) near Basic Park • Significantly higher mercury concentrations were found in the middle of the mill pond near Dooms • In the mill pond, increases in methylmercury account for the increase in total mercury concentrations • Caging clams allowed us to monitor locations where wild clams are not easily found (e.g. Dooms mill pond) • Caged clams showed good survival rates (55.4 - 80.1%) • Some clam cages were lost during high flow (10 of 60)
Sina Pricelius Stacy Davenport Lee Cochran Cheryl Heatwole Tim Shenk Absalom Shank Fred Copithorn
Thanks to…
Mark Lotts Pete Bolton Ashley Young Harrison Green Jacob Hileman Bill Van Wart Ted Turner
Clams taken from North River
Collecting clams (above) and sorting them by size (right)
Caging and Canoeing Clams
Clam Cage Placement Dooms Mill Pond
Hopeman
Parkway
Basic Park
North Park
Dates of Study • Caged Clams: North Park to Basic Park – Placed on July 10, 2004 – Recovered on September 25 (after 77 days) – 13 of 20 cages recovered (65%)
• Caged Clams: Dooms Mill Pond – Placed on July 16, 2004 – Recovered on September 25 (after 71 days) – 18 of 20 cages recovered (90%)
JEANNE FRANCES
Cages recovered
IVAN
Parks Reach: Mercury by Site Mercury in Caged Clams from Parks Reach
100
WWTP outfall
Oxbow
60
40
20
Average Total Hg (ppb)
Methyl Mercury
00 CB 19
C
CB 16
00
00
Site ID
C
CB 14 C
CB 13
00
00 C
CB 11 C
CB 10
00
00 C
CB 09 C
CB 08
00
00 C
CB 07 C
CB 04
00
00 C
CB 03
00 C
CB 02 C
CB 01
00
0
C
Mercury (ppb)
80
Parks Reach: Map of Mercury in Clams Hopeman Parkway North Park Basic Park
Waynesboro wastewater treatment plant
Total mercury concentrations (ppb in clams) are shown by size of red symbol and numbers near cage locations
2nd Street Oxbow Steele Run
US Route 340
Pond Reach: Mercury by Site Mercury in Caged Clams in South River in CCC Sites
220 200 180
140 120 100 80 60
in mill pond
40 20 0 C C C 00 00 C C C 02 00 C C C 03 00 C C C 04 00 C C C 05 00 C C C 06 00 C C C 07 00 C C C 08 00 C C C 09 00 C C C 10 00 C C C 11 00 C C C 12 00 C C C 13 00 C C C 14 00 C C C 16 00 C C C 17 00 C C C 18 00 C C C 19 00
Mercury (ppb)
160
Site ID Average Total Hg
Methyl Hg
Pond Reach: Map of Mercury in Clams
Total mercury concentrations (ppb in clams) are shown by size of red symbol and numbers near cage locations
Mill Pond
mill dam
US Route 340
Dooms
Conclusions from Caged Clam Study, 2004 • Mercury concentrations increase downstream from Dupont’s 001 outfall on South River in Waynesboro • Mercury concentrations increase downstream from an oxbow (Steele Run confluence) near Basic Park • Significantly higher mercury concentrations were found in the middle of the mill pond near Dooms • In the mill pond, increases in methylmercury account for the increase in total mercury concentrations • Caging clams allowed us to monitor locations where wild clams are not easily found (e.g. Dooms mill pond) • Caged clams showed good survival rates (55.4 - 80.1%) • Some clam cages were lost during high flow (10 of 60)
Sina Pricelius Stacy Davenport Lee Cochran Cheryl Heatwole Tim Shenk Absalom Shank Fred Copithorn
Thanks to…
Mark Lotts Pete Bolton Ashley Young Harrison Green Jacob Hileman Bill Van Wart Ted Turner
