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United States Department of Agriculture

Agricultural Research Service

Research Project: PLANT VARIATION IN CD, PB, ZN AND AS ACCUMULATION AND BIOAVAILABILITY AND METHODS TO LIMIT RISK Title: Arsenic Recovery by Stinging Nettle From Lead-Arsenate Contaminated Orchard Soils

Authors
item Codling, Eton
item Rutto, Kipkoriony -

Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 4, 2011
Publication Date: N/A

Interpretive Summary: Soil contamination with arsenic (As) is common in old orchards with a history of lead-arsenate pesticide application. Lead-arsenate was used as foliar sprays to control codling moth (Cydia pomonella) in apple orchards. Arsenic from lead-arsenate persists in the soil for long periods. The use of tolerant plant species with a capacity to accumulate and sequester As in above-ground tissues is one approach for remediating contaminated soils. We conducted a greenhouse experiment to study stinging nettle (Urtica dioica L.) growth and As uptake from five orchard soils with varying levels of As concentration. Nettle is a perennial species which produced large biomass and instant re-growth after harvest. The stinging nettle variety used in this study showed significant tolerance to As concentrations with growth remaining unaffected at soil concentrations below 163 mg kg-1. Nettle bioconcentration of As was 4-6 times the level of water soluble As in the soil, but sequestration was mostly in roots with a shoot-to-root translocation factor of 0.15-0.58. Our results show that through repeated harvest, stinging nettle can be used in the remediation of orchard soils contaminated with As.

Technical Abstract: Soil contamination with arsenic (As) is common in orchards with a history of lead-arsenate pesticide application. This problem is prevalent in the U.S. Northeast where lead-arsenate foliar sprays were used to control codling moth (Cydia pomonella) in apple orchards. Arsenic is not easily biodegradable and persists in the soil for long periods. The use of tolerant plant species with a capacity to accumulate and sequester As in above-ground tissues is one approach for reclaiming contaminated soils. We conducted a greenhouse experiment to study stinging nettle (Urtica dioica L.) growth and As uptake from five orchard soils with varying levels of As contamination. Nettle is a perennial species characterized by high productivity and instant re-growth after harvest of above-ground shoots. The stinging nettle variety used in this study showed significant tolerance to As contamination with growth remaining unaffected at soil concentrations below 163 mg kg-1. Nettle bioconcentration was 4-6 times the level of water soluble As in the soil, but sequestration was mostly in roots with a shoot-to-root translocation factor of 0.15-0.58. Our results show that through repeated harvest, stinging nettle can be used in the remediation of orchard soils contaminated with As.

Last Modified: 10/1/2014
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