|Heighton Davies, Lynne|
|Isensee, Allan - RETIRED ARS EMPLOYEE|
|Abdul Baki, Aref|
|Harman Fetcho, Jennifer|
Submitted to: Environmental Toxicology and Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 5, 2001
Publication Date: January 1, 2002
Citation: Rice, P.J., McConnell, L.L., Heighton Davies, L., Sadeghi, A.M., Isensee, A., Teasdale, J.R., Abdul Baki, A.A., Harman-Fetcho, J.A., Hapeman, C.J. 2002. Comparison of copper levels in runoff from fresh-market vegetable production using polyethylene mulch or a vegetative mulch. Environmental Toxicology and Chemistry. 21(1):24-30. Interpretive Summary: Runoff from agricultural areas where tomatoes are grown in plastic mulch has been implicated in the reported failure of commercial shell fish farms. Copper applied in the form of copper hydroxide is one of the most widely used compounds to control tomato diseases. It has been detected in the Chesapeake Bay and in streams and rivers that flow into the Bay. Elevated levels of copper have been shown to have negative effects on aquatic organisms. This research compared the quantity of soil and copper in runoff from field plots that used a black plastic mulch or a vegetative mulch consisting of mowed hairy vetch. Greater quantities of runoff and soil erosion were observed from plastic mulch plots. Runoff collected from the plots with black plastic mulch contained greater quantities of copper than runoff from plots with the mowed hairy vetch. Eighty percent of the measured copper was found to be associated with soil particles suspended in the water; the remaining copper was dissolved in th water. This work suggests that growing tomatoes in plastic mulch is more harmful to the surrounding ecosystem than growing tomatoes in mowed hairy vetch mulch.
Technical Abstract: Runoff from tomato production using polyethylene mulch has been implicated in the failure of commercial shell fish farms in the Mid-Atlantic Region of the United States. Copper, applied in the form of copper hydroxide, is the most widely used fungicide/bactericide to control tomato diseases. It has been detected in the Chesapeake Bay watershed and elevated levels of copper rhave been shown to have adverse effects on shell fish, fin-fish, and other aquatic organisms. This research evaluates the off-site movement of copper with the dissolved- and particulate-phase of runoff from a controlled field plot containing polyethylene mulch or a vegetative mulch, hairy vetch (Vicia villosa Roth). Runoff collected from polyethylene mulch plots contained significantly (p<0.05) greater loads of dissolved- and particulate-phase copper than runoff from hairy vetch mulch plots. Greater (p<0.05) loads of copper were measured in the particulate-phase than the dissolved-phase of runoff from both mulch treatments with the particulate- phase accounting for more than 80% of the copper loads. The reported toxicity of copper to aquatic organisms and the greater runoff volume, soil loss, and off-site loading of copper measured in runoff from the polyethylene mulch suggests this management practice is less sustainable and may have a greater impact on aquatic ecosystems.