Laboratory quality assurance program.

Heavy metal displacement in salt-water-irrigated soil during phytoremediation.

Common chelating agents used in horticultural fertilizers like ethylenediamine- tetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), and ethylenediami- nedi(o-hydroxyphenylacetic)acid(EDDHA)arenotreadilybiodegradableandmaypersist in the environment, maintaining the capacity to solubilize heavy metals. For this reason, biodegradable chelating agents like ethylenediaminedisuccinic acid (EDDS) are being evaluated for use in horticultural crop production. Therefore, the objectives of the study weretodetermine the effects ofFeEDDSand EDDS on substratepH andcopper (Cu), iron (Fe), manganese (Mn), and zinc (Zn) solubility in peat-based substrate compared with variousFeandchelate-ligandsources.Extractionswereperformedusingthe1:2byvolume substrate analysis method with an incubation period of 24 hours. The control was distilled deionizedwaterextractions.Iron-source(FS)extractantsconsistedof1mgL -1 Fesolutions derivedfromFeEDDS,FeEDTA,FeDTPA,FeEDDHA,andFeSO4.Iron-sourceextractant solution pH ranged from 7.1 (FeEDDS) to 5.4 (FeSO4). The extract pH for all Fe-source treatments was similar at pH 6.7, demonstrating the buffering capacity of the peat-based substrate.Iron recoveryrates for FStreatmentsweredetermined after subtracting Fe that was freely extracted with distilled-deionized water: FeSO4 (13%), FeEDDHA (68%), FeEDDS (73%), FeEDTA (102%), and FeDTPA (121%). Iron-source treatments were not different for Mn, averaging 0.03 mgL -1 , and Cu (0.04 mgL -1 ) and Zn (0.24 mgL -1 )w ere greatest in the FeEDDS treatment. Chelate-ligand (CL) extractants consisted of 5 mM solutions of EDDS, EDTA, and DTPA. Chelate-ligand extractant solution pH ranged from 9.7(EDDS)to2.3(DTPA), and extract solutionpHranged from 7.2(EDDS)to4.7(DTPA). Extractant solutions of EDDS and DTPA resulted in the lowest and highest levels of Cu (0.06 and 0.14 mgL -1 , respectively) and Fe (4.3 and 13.1 mgL -1 , respectively) in extract solutions. Overall, these results suggest that there are no negative implications for the use of FeEDDS with peat-based substrate in terms of horticultural crop production based on substrate Fe solubility, which was not different from FeEDTA.

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Effects of FeEDDS and EDDS on Peat-based Substrate pH and Cu, Fe, Mn, and Zn Solubility

This report describes two episodes of acute cystitis associated with “mixed flora” in an elderly male following a cystoscopy. The initial episode was accompanied by pyuria and a positive nitrite test. Both episodes responded to treatment with nitrofurantoin. Urine cultures were negative prior to the episodes and at a 1-year follow-up.

Laboratory quality assurance program.

Citations

Heavy metal displacement in salt-water-irrigated soil during phytoremediation.

Effects of FeEDDS and EDDS on Peat-based Substrate pH and Cu, Fe, Mn, and Zn Solubility

An Unusual Case of Acute Cystitis Associated with Mixed Flora in Voided Urine in an Adult Male

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