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The results of a pilot-scale phytoremediation study are reported in this paper. Small plots of trees established on a closed municipal waste landfill site were irrigated with recovered groundwater containing 1,4-dioxane (dioxane) and other volatile organic compounds (VOCs). The plots were managed to minimize the leaching of irrigation water, and leaching was quantified by the use of bromide tracer. Results indicated that the dioxane (2.5 microg/L) was effectively removed, probably via phytovolatilization, and that a full-scale phytoremediation system could be used. A system is now in place at the site in which the recovered groundwater can be treated using two different approaches. A physical treatment system (PTS) will be used during the winter months, and a 12 ha phytoremediation system (stands of coniferous trees) will be used during the growing season. The PTS removes VOCs using an air-stripper, and destroys dioxane using a photo-catalytic oxidation process. Treated water will be routed to the local sewer system. The phytoremediation system, located on the landfill, will be irrigated with effluent from the PTS air-stripper containing dioxane. Seasonal use of the phytoremediation system will reduce reliance on the photo-catalytic oxidation process that is extremely energy consumptive and expensive to operate.

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An experiment was conducted in order to study the effects of all possible combinations of three different concentrations of the elements magnesium, calcium, and boron upon strawberry plants of the variety Senator Dunlap growing in sand culture. The effect of these treatments on the contents of the three elements was determined by spectrographic analysis.Increasing the concentration of magnesium in the culture solution tended to increase the accumulation of magnesium and to decrease the accumulation of calcium by the plants. Increasing the concentration of boron in the culture solution tended to increase the accumulation of boron by the plants and to decrease their yield of fruit. All plants growing in a culture solution containing 0.5 p.p.m. of boron developed both a foliar symptom characteristic of boron toxicity, namely, a marginal chlorosis of the leaves, and certain symptoms characteristic of strawberry black root disease, namely, gradually extending necrotic areas upon the crowns and roots. The fact that the foliar chlorosis symptomatic of boron toxicity in strawberry appeared upon plants supplied with a relatively low concentration of boron is confirmation of the low boron requirement of the strawberry. The fact that the typical foliar symptom of boron toxicity was in all cases accompanied by certain symptoms characteristic of black root disease, namely necrosis of crown and roots, seems to suggest that the latter, in this instance, were also symptomatic of boron toxicity.