Effects of Atrazine runoff on Chesapeake Bayaquatic life

Caitlin Andrews

Russell F. Ford

David Lucero

Henrietta Oakley

Satish Serchan

Problem statement: The witch’s brew of non-point source pollutants in runoff entering the Chesapeake Bay is suspected of contributing to the decline of Bay fisheries and ecosystem health.

Goal: This report will assess possible impacts of the common agricultural herbicide Atrazine on theChesapeake Bayestuary, including sub-aquatic vegetation (SAV), fauna dependent on SAV, and the possible role of the chemical in the environment as an endocrine disrupter.

Justification: The herbicide Atrazine is one of the most widely used agricultural chemicals in the Chesapeake Bay watershed. Detectable amounts are found in many watershed rivers and streams, and within the estuary itself. The chemical has been banned in the European Union, and safety concerns about Atrazine are being raised in the US today. The US EPA is currently reviewing the safety of Atrazine, and attempting to model the effects of the pesticide on aquatic ecosystems. Some biologists have called for the substance to be banned in the United States.

Atrazine is very widely found in ppb concentrations within the CB watershed. The Chesapeake Bay is historically an important source of fish and shellfish. Any adverse effects from Atrazine could have widespread negative consequences on the ecological and economic health of the Chesapeake Bay region..

Literature Review: Atrazine is the most extensively used herbicide in the United States for control of weeds in agricultural crops and is toxic to aquatic organisms (U.S. EPA 2003) with about approximately 76 millions pounds of it applied each year (Hayes et. al. 2003). Atrazine is used extensively in the United States, Canada and other countries for the control of weeds in agricultural, especially in corn, sorghum, wheat and soybeans. It is one of the most heavily used pesticides in North America, generally being among the top few in terms of total pounds of herbicide used (Braden et al. 1989; Burridge and Haya 1988; Ciba-Geigy 1994; Council on Environmental Quality 1984; Moxley 1989; Pike 1985; Richards and Baker 1993). Annual domestic usage during the past two decades has been in the general range of 30 to 40 million kilograms applied to approximately 70 million acres of farm land in the U.S. (U.S. EPA 2000). Due to the negative impacts atrazine is shown to have on aquatic life both animals and vegetation,it has been banned in the European Union. Studies on tetragenic effects of atrazine in aquatic species has shown that as low as 0.1 part per billion of atrazine in surface water tetragenically effects frogs by causing the male frog gonads to produce eggs – effectively turning males into hermaphrodites (Hayes, et. al. 2003). In the Chesapeake Bay area, loss of submerged aquatic vegetation has been linked to increase in use of Atrazine around the bay area resulting in overall decline of Chesapeake Bay’s fish and waterfowl productivity (Christopher et. al. 1992).

Watershed land use patterns play important roles in the abundance of blue crabs, bivalves, and other estuarine fauna; blue crab populations do not flourish in watersheds associated with agricultural land use (King et. al 2005). Blue crabs play an important role in trophic cascades and predator-prey dynamics. Blue crab populations are controlled by predation in the juvenile stages and require refuge during early development, and loss of seagrass beds as habitat for blue crab juveniles may force them upstream to lower-salinity waters with fewer predators (Posey et. al, 2005). Thin-shelled clams make up a large portion of the diet of blue crabs, and they dominate benthic communities in the Chesapeake Bay; high-density clam populations found in up-river sand and mud flats supported the most juvenile blue crab growth (significantly greater in the spring and summer months) (Seitz et. Al., 2005). Atrazine is shown to have non-lethal mutagenetic effects on species of fish (Oreochromis niloticus) at concentrations much lower than the reported LD50 (Ventura et. al, 2008), as well as on mummichog (Fundulus heteroclitus) larvae (Fortin et. al, 2008).

Proposed Effort: We have reserved a UVM van and two rooms on the Chesapeake Bay Eastern Shore for Spring Break Week, billed to the Arctic LTER Streams Research Group. In addition to eating soft-shell crabs and drinking beer, we propose an literature-review based assessment of Atrazine within the Chesapeake Bay ecosystem. Impacts to review include direct harm to aquatic fauna, loss of aquatic flora, changes in eco-system structure including trophic cascade and predator-prey relationships, endocrine disruption, lowered sperm counts in human consumers of Bay seafood, and the possible near-term arrival of environmental apocalypse.

Effort Assignment: Our student team is meeting weekly with frequent additional e-mail to share and discuss relevant background literature, with individual focuses including watershed description (D. Lucero), fate and transport of Atrazine in surface waters (S. Serchan), impacts on aquatic flora (C. Andrews) and fauna (H. Oakley), and U.S. EPA assessment and regulation of Atrazine (R. Ford). The report will be jointly written, with additional production, writing, and copyediting by R. Ford and H. Oakley. A Powerpoint presentation will be jointly presented, with slides produced by D. Lucero and S. Satish.

Project Timeline

12 March: Meet to draft skeleton outline of report. Assign sections to be drafted by each team member.

27 March: Section drafts due. Begin production of unified rough draft of report.

2 April: Meet to review rough draft

10 April: Submit draft Project Report for review. Choose discussion paper and begin production of Powerpoint presentation for group discussion.

15 April: Submit chosen peer-reviewed paper for in-class discussion

22 April: Project Presentation/ discussion

24 April: Receive comments of draft Project Report. Meet to begin revision.

1 May: Submit final Project Report. Meet 5:00 pm at Burlington Flatbread for team internal critique and celebration.

6-9 May (tbd) Final team meeting and critique with B. Bowden.

Literature Cited

Christopher SV, Bird KT. The effects of herbicides on development Myriophyllum spicatum L. cultured in vitro. J Environ Qual 1992;21:203-7.

Fortin, M.G., C.M. Couillard, J. Pellerin, M. Lebeuf. Effects of salinity on sublethal toxicity of atrazine to mummichog (Fundulus heteroclitus) larvae. Marine Environmental Research 65 (2008) 158-170

King, R.S., A.H. Hines, F.D. Craige, S. Grap. Regional, watershed and local correlates of blue crab and bivalve abundances in subestuaries of Chesapeake Bay, USA. Journal of Experimental Marine Biology and Ecology 319 (2005) 101-116.

Posey, M.H., T.D. Alphin, H. Harwell, B. Allen. Importance of low salinity areas for juvenile blue crabs, Callinectes sapidus Rathbun, in river-dominated estuaries of southeastern United States. Journal of Experimental Marine Biology and Ecology 319 (2005) 81-100

Seitz, R.D., R.N. Lipcius, M.S. Seebo. Food availability and growth of the blue crab in seagrass and unvegetated nurseries of Chesapeake Bay. Journal of Experimental Marine Biology and Ecology 319 (2005) 57-68.

Ventura, B. de Campos, D. de Fransceschi de Angelis, M.A. Marin-Morales. Mutagenic and genotoxic effects of the Atrazine herbicide in Oreochromis niloticus (Perciformes, Cichlidae) detected by the micronuclei test and the comet assay. Pesticide Biochemistry and Physiology 90 (2008) 42-51.

Hayes TB, Collins A, Mendoza M, Noriega N, Stuart AA, VonkA. Hermaphroditic,

demasculinized frogs exposed to the herbicide atrazine at low ecologically relevant doses. Proc. Nat.Acad. Sci. USA (2002) 99:5476-5480.

Hayes T, Haston K, Tsui M, Hoang A, Haeffele C, and Vonk A. Atrazine-Induced Hermaphroditism at 0.1 ppb in American Leopard Frogs. (2003). Environmental HealthPerspectives 111.