Author
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Codling, Eton |
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Submitted to: Open Agriculture Journal
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 6/4/2014 Publication Date: 10/6/2014 Citation: Codling, E.E. 2014. Accumulation of lead and arsenic by lettuce grown on lead-arsenate contaminated orchard soils. Open Agriculture Journal. 8:35-40. Interpretive Summary: Lead-arsenate insecticides were used from the 1900's to the 1960’s to control codling moth (Cydia pomonella) in apple orchards. Lead and arsenic are generally immobile and remain in the surface soil. Some of these contaminated lands are being used for vegetable crop production. Consumption of vegetable crops grown on lead and arsenic contaminated soil could potentially become a health risk. To address these concerns, an experiment was establish to: 1) determine lead and arsenic uptake by lettuce and 2) determine the movement of lead and arsenic lettuce root to leaves. Lettuce was grown in four orchard soils with total lead and arsenic concentrations ranging from 350-961 and 93-291 mg kg,-1 respectively. Lettuce yield reduced 18, 11, 38 and 31 percent for plants grown on Bagstown, Hudson, Spike and Cashmont soils respectively. Lettuce did accumulate lead and arsenic with the largest amount in the older leaves. Lead and arsenic concentrations ranged from 0.44 to 3.91 and 4.65 to 24.1mg kg-1 respectively. With such high levels of arsenic in the lettuce, there is no established standard for arsenic in food; care should be taken when these soils are used for lettuce production without soil remediation. Technical Abstract: Lead-arsenate was one of the preferred insecticides used as foliar spray to control codling moth (Cydia pomonella) in apple (Malus sylvestris Mill) orchards from the 1900's to the 1960’s. Lead and arsenic are generally immobile and remain in the surface soil. Some of these contaminated lands are now being used for vegetable crop production. There are concerns of possible accumulation of lead and arsenic in vegetable crops grown in these soils. Objectives were to: 1) determine lead and arsenic uptake by lettuce and 2) determine the translocation into lettuce leaves. Lettuce (Lactuca sativa L) was grown for 60 days in four orchard soils (Bagstown, Hudson, Spike and Cashmont) with total lead and arsenic concentrations ranging from 350-961 and 93-291 mg kg-1 respectively. Plants were harvested and separated in younger and older leaves, rinsed and freeze dried. Biomass yield reduced 18, 11, 38 and 31 percent for plants grown on Bagstown, Hudson, Spike and Cashmont soils respectively. Lettuce did accumulate lead and arsenic with the largest amount in the older leaves. Lead and arsenic concentrations ranged from 0.44 to 3.91 and 4.65 to 24.1mg kg-1 respectively. Unlike arsenic levels in water, there are no established levels for arsenic in food; therefore, it is difficult to determine if the arsenic levels observed in this study should be of concern to the consumers. Until there are standard limits for arsenic in food, care should be taken when these soils are used for lettuce production without soil remediation. |
