Many fields and gardens across Vermont were exposed to flood waters in 2011. The vast majority of these can be planted in the normal fashion this year. The exceptions would be fields that have obvious signs of contamination, such as unusual soil odors or hazardous debris. Growers with flooded fields are urged to submit a soil sample for testing by the UVM testing lab to determine if nutrient levels have been affected and if heavy metals have been deposited. See: http://pss.uvm.edu/ag_testing/?Page=soils.html or call 802-656-3030, the cost is $24. To date, testing of soil from over 150 flooded fields in Vermont has revealed no sign of heavy metal contamination. If soils have an odor of fuel or if fuel tanks were flooded or deposited nearby, a soil sample can be tested for Total Petroleum Hydrocarbons by Endyne Labs in Williston; cost is $75. Contact them for information: http://www.endynelabs.com/ or (802) 879-4333.
Testing for microbial contamination is not practical due to the number of possible pathogens and variability in their population across a field. However, crops that are being planted on soils that flooded last year should be fine for human consumption. After being exposed to solar radiation, cold temperatures in winter, and other factors that limit their survival in soil there is little risk of microbial pathogens from last year's flooding. For example, the commonly accepted waiting period to reduce food safety risks in food crops after application of raw manure is 120 days. Of course, common sense washing routines should be followed before eating produce.
Written by Vern Grubinger, University of Vermont Extension March 2012