Herbicides in Kansas waters: Evaluations of the effects of agricultural runoff and aquatic weed control on aquatic food chains
deNoyelles, F; Kettle, D
HERO ID
11144275
Reference Type
Technical Report
Year
1980
Language
English
| HERO ID | 11144275 |
|---|---|
| Year | 1980 |
| Title | Herbicides in Kansas waters: Evaluations of the effects of agricultural runoff and aquatic weed control on aquatic food chains |
| Authors | deNoyelles, F; Kettle, D |
| Publisher Text | The Kansas Water Resources Research Institute at The University of Kansas |
| City | Lawrence, KS |
| Abstract | A project was conducted using experimental ponds for studying the effects of an agricultural herbicide on aquatic food chains. Atrazine, one of the most heavily used herbicides in Midwest agriculture, was added to ponds and the ensuing responses were followed through four months. With single 20 μg/liter and 500 μg/liter additions to the ponds, effects were recorded throughout the food chain. After one day of exposure rates of phytoplankton photosynthesis declined at both levels, with the higher level causing an almost complete inhibition. Phytoplankton succession was altered within a few days at both levels, with resistant species increasing in abundance. The actual resistance of these species to atrazine, which is known to be a photosynthetic inhibitor affecting a wide variety of plants, was verified in the laboratory. The grazing zooplankton were also affected within the first few weeks of exposure as their phytoplankton food source was altered. The growth of aquatic flowering plants was also reduced at both levels. Some members of the aquatic food chain were unaffected, particularly the benthic insects, although effects were recorded at the highest level of these food chains, the fish. Of the three types of fish (bluegill sunfish, channel catfish, gizzard shad) originally stocked in the ponds, all survived but with reduced growth at the 500 μg/liter- level. The only fish to reproduce in the ponds, bluegill sunfish, showed greatly reduced numbers of progeny at both levels. The concentrations of atrazine in the ponds were monitored, showing its persistence with 75% of the original concentration present after 114 days. In Midwest waters concentrations of 500 μg/liter are recorded in waters directly associated with agricultural operations, such as irrigation waters while 20 μg/liter is at the high extreme of concentrations found more widespread. Though data from monitoring atrazine concentrations in natural habitats is sparce 1 μg/liter to 5 μg/liter seem common in many Midwest waters. In laboratory experiments with these more common concentrations we also demonstrated reductions in phytoplankton photosynthesis. This indicates the possibility, awaiting further demonstration, that even at common concentrations atrazine may be affecting phytoplankton photosynthesis in many Midwest waters. Other herbicides studied in this project included 5 other triazine herbicides (propazine, metribuzin, terbutryn, cyanazine, simazine) which in the laboratory were similar to atrazine in the intensity of reducing phytoplankton photosynthesis. ln the state of Kansas triazine herbicides accounted for one third of the total herbicide usage in 1978. |
| Report Number | NR 475436-06 |
| Url | https://biosurvey.ku.edu/pub/herbicides-kansas-waters-evaluations-effects-agricultural-runoff-and-aquatic-weed-control |
| Is Certified Translation | No |
| Dupe Override | No |
| Number Of Pages | 49 |
| Is Public | Yes |
| Language Text | English |