Title
Copper Bioaccumulation in Snails in a Simulation of Silver Bow Creek
Abstract
Historic mining and smelting contaminated the Silver Bow Creek (SBC) watershed which is now being reclaimed under the Superfund law. Copper and other heavy metals continue to impair water quality, aquatic habitat, and stream life in SBC. To study bioaccumulation of copper in the food chain under conditions similar to SBC, I simulated the creek’s conditions in the laboratory.
The simulated food chain included the biofilm growing on the rocks in SBC and freshwater snails of the Pulmonata Lymnaeoidea group -- ideal subjects for this study, because they are fairly tolerant of metals, graze on the biofilm, and occur naturally in SBC.
Snails and water were collected from Blacktail Creek, a relatively unpolluted tributary of SBC. Rocks with biofilm (including attached algae) were collected from SBC. A dilute solution of CuSO4 was used as a source for copper.
To study metals bioaccumulation at different copper levels, I used four aquaria containing Blacktail Creek water with copper added in these amounts.
No additional copper (‘control’);
- enough to reach the LD-50 (lethal dose 50 – that is the concentration at which 50% of the organisms would be killed in a certain amount of time) of the snails;
- enough to simulate SBC conditions during a storm event,
- enough to simulate levels in SBC most of the time (chronic exposure levels).
I monitored each aquaria’s concentration of copper in water daily for 17-35 days with a HACH portable colorimeter. I also digested samples of water, biofilm and snails about 5 times over this period, and analyzed those digests in an Atomic Absorption Spectrophotometer.
In all the aquaria with copper additions, the level of copper in snails fairly quickly tracked the levels of copper in the water. Copper levels in biofilms did not track the water copper levels well, possibly because of analytical problems.
In the Storm simulation aquarium, copper was added in a ‘slug’, and copper levels rose quickly in water & snails and then dropped quickly in both. In the Chronic and LD-50 aquaria, high copper levels were gradually built up by multiple additions of copper. In these situations, copper levels in snails gradually rose, and 50% of the snails had died after 16 days of exposure and after reaching a body burden of 1833 ppm.
Start Date
1-4-2005 1:00 PM
End Date
1-4-2005 3:00 PM
Document Type
Poster
Copper Bioaccumulation in Snails in a Simulation of Silver Bow Creek
Historic mining and smelting contaminated the Silver Bow Creek (SBC) watershed which is now being reclaimed under the Superfund law. Copper and other heavy metals continue to impair water quality, aquatic habitat, and stream life in SBC. To study bioaccumulation of copper in the food chain under conditions similar to SBC, I simulated the creek’s conditions in the laboratory.
The simulated food chain included the biofilm growing on the rocks in SBC and freshwater snails of the Pulmonata Lymnaeoidea group -- ideal subjects for this study, because they are fairly tolerant of metals, graze on the biofilm, and occur naturally in SBC.
Snails and water were collected from Blacktail Creek, a relatively unpolluted tributary of SBC. Rocks with biofilm (including attached algae) were collected from SBC. A dilute solution of CuSO4 was used as a source for copper.
To study metals bioaccumulation at different copper levels, I used four aquaria containing Blacktail Creek water with copper added in these amounts.
No additional copper (‘control’);
- enough to reach the LD-50 (lethal dose 50 – that is the concentration at which 50% of the organisms would be killed in a certain amount of time) of the snails;
- enough to simulate SBC conditions during a storm event,
- enough to simulate levels in SBC most of the time (chronic exposure levels).
I monitored each aquaria’s concentration of copper in water daily for 17-35 days with a HACH portable colorimeter. I also digested samples of water, biofilm and snails about 5 times over this period, and analyzed those digests in an Atomic Absorption Spectrophotometer.
In all the aquaria with copper additions, the level of copper in snails fairly quickly tracked the levels of copper in the water. Copper levels in biofilms did not track the water copper levels well, possibly because of analytical problems.
In the Storm simulation aquarium, copper was added in a ‘slug’, and copper levels rose quickly in water & snails and then dropped quickly in both. In the Chronic and LD-50 aquaria, high copper levels were gradually built up by multiple additions of copper. In these situations, copper levels in snails gradually rose, and 50% of the snails had died after 16 days of exposure and after reaching a body burden of 1833 ppm.