Iron tissue storage and hemoglobin levels of deficient rats repleted with iron bound to the caseinophosphopeptide 1-25 of beta-casein.

Caseinophosphopeptides (CPP) issued from enzyme digestion of caseins bind cations and keep them soluble in the digestive tract. They could be used as ligands to improve iron (Fe) bioavailability. Fe-deficient young rats were repleted with Fe (40 or 200 mg/kg of diet) bound either to the beta-CN (1-25) of beta-casein or to whole beta-casein or as FeSO(4). A control pair-fed group was given 200 mg of Fe (FeSO(4))/kg of diet for 6 weeks. After repletion, hemoglobin concentration of the control group was reached only by the ) animals fed 200 mg of Fe/kg; beta-CN (1-25) bound Fe (40 and 200 mg) produced higher Fe liver and spleen stores than FeSO(4). Binding Fe to the whole, nonhydrolyzed beta-casein gave results intermediate between the other experimental groups. Binding Fe to phosphoserine residues of low molecular weight CPP improved its ability to cure anemia and to restore iron tissue stores, as compared to Fe bound to the whole casein and to inorganic salts.     

Estimation of the bioavailability of iron.

Eight laboratories conducted a test for the estimation of the bioavailability of iron from 4 sources, using depleted male albino rats. Ferrous sulfate was used as the reference standard. Ferric orthophosphate was found to have a relative biological value of 11 (range 6-22), an old sample of hydrogen-reduced iron 27 (range 15-41), and ferric citrate 96 (range 75-125). Good results were obtained with a simplified basal diet prepared without ingredients that had previously contributed variable quantities of iron. There was no apparent advantage in using the change in hemoglobin during the repletion period instead of the final homoglobin value as the criterion of response to iron supplements. Several statistical treatments of the data yielded similar conclusions regarding relative biological values of the iron sources.     

Effect of bread baking on the bioavailability of hydrogen-reduced iron powder added to unenriched refined wheat flour

Elemental iron powders are widely used to fortify flour and other cereal products. Our objective was to test the hypothesis that baking enhances the bioavailability of elemental iron powders by oxidizing Fe(0) to Fe(2+) or Fe(3+). An in vitro digestion/Caco-2 cell culture model and a piglet model were used to measure bioavailability. Bread flour, either unfortified or fortified with hydrogen-reduced (HR) iron powder or FeSO(4) (300 mg Fe/kg flour), was baked into bread. For the in vitro studies, bread samples were treated with pepsin at pH 2, 3, 4, 5, 6, or 7 and subsequently incubated with pancreatic enzymes at pH 7 in a chamber positioned above monolayers of cultured Caco-2 cells. Ferritin formation in the cells was used as an index of iron bioavailability. Ferritin formation in cells fed HR Fe bread was similar to cells fed FeSO(4) bread when the peptic digestion was conducted at a pH 2 but lower when the peptic phase was conducted at pH 3, 4, 5, 6, or 7 (P < 0.05). Pig diets containing 35% dried bread were prepared and fed to cross-bred (Hampshire x Landrace x Yorkshire) anemic pigs in two studies. The rate of increase in hemoglobin Fe over the feeding period was used to calculate relative biological value (RBV), an index of iron bioavailability. In the first pig study, RBV of HR Fe added to flour prior to baking was 47.9% when compared to FeSO(4) fortified flour (P < 0.05). In the second pig study, a third treatment consisting of unfortified bread with HR iron added during diet mixing (after bread baking) was included. RBVs of the HR Fe diet (Fe added after baking) and HR Fe diet (Fe added before baking) were 40.1% and 53.5%, respectively, compared to the FeSO(4) diet. Differences in RBV between the HR Fe (before and after baking) and FeSO(4) (before baking) treatment groups were significant, but the difference between the before and after HR treatment groups was not significant. We conclude that bread baking does not enhance the bioavailability of elemental iron powders.     

The importance of the proportion of heme/nonheme iron in the diet to minimize the interference with calcium, phosphorus, and magnesium metabolism on recovery from nutritional ferropenic anemia.

The digestive utilization of Fe and its nutritive interaction with Ca, P, and Mg were studied in rats with nutritional ferropenic anemia. The diet contained 80% ferric citrate and 20% heme iron (80/20 diet). The weight gain, digestive utilization of Fe, and regeneration efficiency of hemoglobin and seric Fe were higher in iron-deficient rats (ID) fed the 80/20 diet than in iron-deficient rats fed the 50/50 diet (Campos et al., 1996). The phospho-calcic metabolism, which is adversely affected in ferropenic anemia, returned to normal values when iron was added to the diet. The digestive utilization of Mg, which fell with the 50/50 diet (Campos et al., 1996), returned to normal values when the ferropenic anemia was reversed with the 80/20 diet. In a state of iron deficiency, certain parameters related to the glucose and lipid metabolism are affected; the glucose and triglycerides values return to a normal range with the 80/20 diet.     

Evaluation of iron bioavailability from bonito dark muscle using anemic rats

The bioavailability of iron from ferrous sulfate (FeII-S), heme iron prepared from hemoglobin (HIP), and bonito dark muscle (BDM) was assessed in anemic rats using a hemoglobin regeneration efficiency (HRE) method. Freeze-dried BDM (FD), boiled and freeze-dried BDM (B/FD), and boiled and smoke-dried BDM (B/SD) were used as BDM source. Rats were made anemic by feeding on an iron-deficient diet for 28 days. To replete their iron levels, anemic rats were then fed on a diet containing iron at a level of 17 ppm for 14 days. Rats receiving FeII-S gained significantly more weight and had greater food intake and higher HRE compared to the other four groups. The bioavailability of iron from HIP was poor compared with that from FeII-S and BDM. When the HRE of rats fed FeII-S was 100, that of rats fed BDF was approximately 80. These results suggest that BMD is an effective dietary source of iron.     

In vitro iron availability from iron-fortified whole-grain wheat flour

Iron deficiency is the most common nutritional disorder worldwide. Iron fortification of foods is considered to be the most cost-effective long-term approach to reduce iron deficiency. However, for fortified foods to be effective in reducing iron deficiency, the added iron must be sufficiently bioavailable. In this study, fortification of whole-grain wheat flour with different sources of iron was evaluated in vitro by measuring the amount of dialyzable iron after simulated gastrointestinal digestion of flour baked into chapatis and subsequent intestinal absorption of the released iron using Caco-2 cell layers. The dialyzability of iron from iron-fortified wheat flour was extremely low. Additions of 50 mg/kg iron to the flour in the form of ferrous sulfate, Ferrochel amino acid chelate, ferric amino acid chelate taste free (TF), Lipofer, ferrous lactate, ferrous fumarate, ferric pyrophosphate, carbonyl iron, or electrolytic iron did not significantly increase the amount of in vitro dialyzable iron after simulated gastrointestinal digestion. In contrast, fortification of flour with SunActive Fe or NaFeEDTA resulted in a significant increase in the amount of in vitro dialyzable iron. Relative to iron from ferrous sulfate, iron from SunActive Fe and NaFeEDTA appeared to be 2 and 7 times more available in the in vitro assay, respectively. Caco-2 cell iron absorption from digested chapatis fortified with NaFeEDTA, but not from those fortified with SunActive Fe, was significantly higher than from digested chapatis fortified with ferrous sulfate. On the basis of these results it appears that fortification with NaFeEDTA may result in whole-grain wheat flour that effectively improves the iron status.     

Tissue iron distribution and adaptation of iron absorption in rats exposed to a high dietary level of NaFeEDTA

Although it has been shown that iron absorption from NaFeEDTA, a promising iron fortificant, is effectively down-regulated in iron-loaded rats, effects of prolonged exposure to high dietary levels of NaFeEDTA are not well understood. The objectives of this study were to determine whether rats can adapt to a high dietary level of NaFeEDTA by down-regulating iron absorption, and to determine effects on tissue iron distribution, with or without an iron absorption inhibitor. Male Sprague-Dawley rats were exposed to diets supplemented with FeSO4 or NaFeEDTA at 1200 mg of Fe/kg of diet, with or without tea, for 27 days. Iron absorption measured by whole-body counting before and after exposure showed that rats adapted to the high dietary level of FeSO4 or NaFeEDTA by down-regulating iron absorption to a similar extent. However, nonheme iron concentrations in liver and spleen were about 35-50% lower, whereas the concentration in kidney was about 300% higher in rats fed NaFeEDTA, compared to rats fed FeSO4. Tea had no major impact on iron absorption or iron status, regardless of iron source. Our results showed that although iron absorption was down-regulated similarly, body iron distribution was markedly different between rats exposed to FeSO4 and those exposed to NaFeEDTA. Further studies are warranted to determine the effects of prolonged exposure to dietary NaFeEDTA on kidney iron accumulation and kidney function.     

Effect of Nano Fe-Chelate,Fe-Eddha and FeSO4 on Vegetative Growth,Physiological Parameters and Some Nutrient Elements Concentrations of Four Varieties of Lettuce (Lactuca sativa L.) In NFT System

In order to investigate the effects of different iron (Fe) sources (nano iron (Fe)-chelate, Fe- ethylenediamine-di(o-hydroxy phenyl acetic acid (EDDHA) and iron (II) sulfate (FeSO₄)) on lettuce (Lactuca sativa) growth in alkaline solutions, an experiment was arranged in hydroponic system. This study showed that leaf Fe content and overall plant growth was significantly increased by Fe-chelate application, and the highest values of leaf Fe, plant pigments and vegetative growth were recorded in plants treated with nano Fe-chelate. The lowest Fe, chlorophyll, carotenoids and soluble sugars in leaves were observed in FeSO₄ treatment. There were no difference in soluble sugars contents of plants between nano Fe-chelate and Fe-EDDHA treatments. Fertilization of lettuce plants with different Fe-chelate sources had a beneficial effect on the manganese (Mn) and zinc (Zn) uptake in plants. It is concluded that application of chelated form of Fe (especially nano Fe-chelate) must be performed in hydroponic system with alkaline water, to overcome Fe deficiencies and to make better nutritional status.     

Iron dissociates from the NaFeEDTA complex prior to or during intestinal absorption in rats

Sodium iron ethylenediaminetetraacetate (NaFeEDTA) has superior iron bioavailability especially in foods containing iron absorption inhibitors. However, mechanisms involved in the absorption and subsequent partitioning of iron complexed with EDTA are poorly understood. Our objectives were to compare retention and tissue distribution of iron administered to rats either as FeSO4 or NaFeEDTA, either orally (OR) or subcutaneously (SC). Weanling rats were fed semipurified diets supplemented with either FeSO4 or NaFeEDTA for 7 days. They were then given a meal containing 59Fe-labeled FeSO4 or NaFeEDTA, or they were injected SC with these two forms of radiolabeled Fe. 59Fe retention was measured by whole body counting. Urine was collected and counted at 24 h intervals throughout the counting period. Tissue samples were analyzed for nonheme iron and 59Fe activity. Absorption of iron from FeSO4 or NaFeEDTA was similar (57.7 and 53.4%, respectively). Seventy-seven percent of the injected Na59FeEDTA was excreted in the urine within 24 h, whereas only 0.5, 0.8, and 1.4% of the injected 59FeSO4, oral 59FeSO4, and oral Na59FeEDTA, respectively, was excreted in the urine. The nonheme iron content was lower in the liver and spleen, by 56.8 and 28.4%, respectively, among rats consuming the NaFeEDTA diet as compared to rats fed FeSO4. We conclude that iron is dissociated from EDTA prior to or during intestinal absorption and that some fraction of the dissociated EDTA is absorbed separately from the iron.     

Influence of pH, iron source, and Fe/ligand ratio on iron speciation in lignosulfonate complexes studied using Mössbauer spectroscopy. Implications on their fertilizer properties

Iron chlorosis is a very common nutritional disorder in plants that can be treated using iron fertilizers. Synthetic chelates have been used to correct this problem, but nowadays environmental concerns have enforced the search for new, more environmentally friendly ligands, such as lignosulfonates. In this paper, Fe coordination environment and speciation in lignosulfonate (LS) complexes prepared under different experimental conditions were studied by (57)Fe M?ssbauer spectroscopy in relation to the Fe-complexing capacities, chemical characteristics of the different products, and efficiency to provide iron in agronomic conditions. It has been observed that the complex formation between iron and lignosulfonates involves different coordination sites. When Fe(2+) is used to prepare the iron-LS product, complexes form weak adducts and are sensitive to oxidation, especially at neutral or alkaline pH. However, when Fe(3+) is used to form the complexes, both Fe(2+) and Fe(3+) are found. Reductive sugars, normally present in lignosulfonates, favor a relatively high content of Fe(2+) even in those complexes prepared using Fe(3+). The formation of amorphous ferrihydrite is also possible. With respect to the agronomical relevance of the Fe(2+)/Fe(3+) speciation provided by the M?ssbauer spectra, it seems that the strong Fe(3+)-LS complexes are preferred when they are applied to the leaf, whereas root uptake in hydroponics could be more related with the presence of weak bonding sites.     

Iron-accelerated cumene hydroperoxide decomposition in hexadecane and trilaurin emulsions

Free radicals arising from lipid peroxides accelerate the oxidative deterioration of foods. To elucidate how lipid peroxides impact oxidative reactions in food emulsions, the stability of cumene hydroperoxide was studied in hexadecane or trilaurin emulsions stabilized by anionic (sodium dodecyl sulfate; SDS), nonionic (Tween 20), and cationic (dodecyltrimethylammonium bromide; DTAB) surfactants. Fe(2+) rapidly (within 10 min) decomposed between 10 and 31% of the cumene hydroperoxide in Tween 20- and DTAB-stabilized emulsions at pH 3.0 and 7.0 and in the SDS-stabilized emulsion at pH 7.0 with no further decomposition of peroxides occurring for up to 3 h. In SDS-stabilized emulsions at pH 3.0, Fe(2+) decreased peroxides by 90% after 3 h. Decomposition of peroxides in the absence of added iron and by Fe(3+) was observed only in SDS-stabilized emulsions at pH 3.0. These results suggest that peroxide decomposition by iron redox cycling occurs when iron emulsion droplet interactions are high.     

Iron bioavailability of hemoglobin from soy root nodules using a Caco-2 cell culture model

Heme iron has been identified in many plant sources-most commonly in the root nodules of leguminous plants, such as soy. Our objective was to test the effectiveness of soy root nodule (SRN) and purified soy hemoglobin (LHb) in improving iron bioavailability using an in vitro Caco-2 cell model, with ferritin response as the bioavailability index. We assessed bioavailability of iron from LHb (either partially purified (LHbA) or purified (LHbD)) with and without food matrix and compared it with that from bovine hemoglobin (BHb), ferrous sulfate (FeSO4), or SRN. Bioavailability of each treatment was normalized to 100% of the FeSO4 treatment. When iron sources were tested alone (100 ug iron/mL), ferritin synthesis by LHbD and BHb were 19% (P > 0.05) and 113% (P < 0.001) higher than FeSO4, respectively. However, when iron sources were used for fortification of maize tortillas (50 ppm), LHbA and BHb showed similar bioavailability, being 27% (P < 0.05) and 33% (P < 0.05) higher than FeSO4. Heat treatment had no effect on heme iron but had a significant reduction on FeSO4 bioavailability. Adding heme (LHbA) iron with nonheme (FeSO4) had no enhancement on nonheme iron absorption. Our data suggest that heme iron from plant sources may be a novel value-added product that can provide highly bioavailable iron as a food fortificant.     

Iron uptake by Caco-2 cells from NaFeEDTA and FeSO4: Effects of ascorbic acid, pH, and a Fe(II) chelating agent

Sodium iron(III) ethylenediaminetetraacetate (NaFeEDTA) has considerable promise as an iron fortificant because of its high bioavailability in foods containing iron absorption inhibitors. In this study, uptakes of iron from NaFeEDTA, FeSO4, and FeCl3 by Caco-2 cells were compared in the absence or presence of ascorbic acid (AA), an iron absorption enhancer; at selected pH levels; and in the absence or presence of an iron absorption inhibitor, bathophenanthroline disulfonic acid (BPDS). Ferritin formation in the cells was used as the indicator of iron uptake. Uptake from all three Fe sources was similar in the absence of AA. Adding AA at a 5:1 molar excess as compared to Fe increased uptake by 5.4-, 5.1-, and 2.8-fold for FeSO4, FeCl3, and NaFeEDTA, respectively. The smaller effect of AA on uptake from NaFeEDTA may be related to the higher solubility of NaFeEDTA and/or the strong binding affinity of EDTA for Fe3+, which may prevent AA and duodenal cytochrome b from effectively reducing EDTA-bound Fe. Uptake was inversely related to the pH of the media over a range of 5.8-7.2. Because uptake by DMT-1 is proton-coupled, the inverse relationship between pH and Fe uptake in all three iron sources suggests that they all follow the DMT-1 pathway into the cell. Adding BPDS to the media inhibited uptake from all three iron compounds equally. Because BPDS binds Fe2+ but not Fe3+ and because only Fe2+ is transported by DMT-1, the finding that BPDS inhibited uptake from NaFeEDTA suggests that at least some iron dissociates from EDTA and is reduced just as simple inorganic iron at the brush border membrane of the enterocyte. Taken together, these results suggest that uptake of iron from NaFeEDTA by intestinal enterocytes is regulated similarly to uptake from iron salts.     

Iron and zinc bioavailability in rats fed intrinsically labeled bean and bean-rice infant weaning food products

Beans are the core of the Latin American diet and contain iron and zinc. However, the bioavailability of these trace minerals from beans is low. The objective of this study was to determine if the bioavailability of iron and zinc could be improved with the use of fermentation and germination processing technologies. Black beans native to Costa Rica were grown hydroponically with either radioactive iron or zinc. The influence of fermentation and germination on iron and zinc bioavailability from intrinsically labeled infant weaning food products based on black beans and beans-rice was determined in rats. Mineral bioavailability was determined using whole-body (59)Fe retention for iron, and whole-body (65)Zn retention and incorporation of radiolabel into bone for zinc. Percent absorption of (59)Fe from fermented products ranged between 48.0 and 58.0. Percent absorption of (65)Zn ranged from 57.0 to 64.0. Fermentation did not increase iron bioavailability in rats fed fermented beans without rice. Fermentation of cooked beans significantly increased zinc retention. Germination significantly enhanced iron retention from cooked beans from 46 to 55% and from cooked beans-cooked rice from 34 to 48%. Germination significantly improved zinc absorption and retention from cooked beans without added rice.     

Iron Sources Effects on Growth,Physiological Parameters and Nutrition of Cacao

Productivity and sustainability of cacao (Theobroma cacao L.) in tropical soils are affected by levels of iron. Information is lacking on the cacao response to various sources of iron (Fe). A greenhouse experiment was conducted to evaluate the effects of five iron sources iron sulfate heptahydrate, ferric ethylenediamine-N,N’-bis(2-hydroxyphenylacetic acid), ferric diethylenetriaminepentaacetic acid, ferric ethylenediaminetetraacetic acid, fiesta herbicide (FeSO₄ · 7H₂O, FeEDDHA, FeDTPA, FeEDTA,) at 10 mg Fe kg^?1 soil on growth, photosynthesis, content of photosynthetic pigments and starch and macro- and micronutrient nutrition of cacao. The various iron sources had significant effects on shoot and root dry biomass accumulation, leaf chlorophyll a and b content, carotenoid levels, SPAD index and P_N. These parameters were significantly correlated with concentration, uptake, influx, and transport and use efficiency of Fe. In cacao net photosynthesis, stomatal conductance, internal carbon dioxide (CO₂)_, and transpiration in leaf level responded differently to the sources of Fe. Invariably, macro and micronutrient uptake, influx, transport, and use efficiency showed differential responses to sources of iron but significant effects were only observed for copper (Cu), Fe, manganese (Mn), and zinc (Zn). Overall, FeDTPA, FeEDTA and FeHEDTA could be the best sources of Fe in improving, growth, photosynthesis and macro and micro nutrition of cacao.     

Blood powder,a source of iron for plants

Natural materials that possess chelating ability for iron (Fe) such as plant and animal residues have been used as Fe sources for plants. A solution culture study and a soil incubation study were conducted to investigate use of poultry blood powder as an Fe source for plants. Iron in blood is chelated by the heme group present in hemoglobin molecule. Stability of Fe in this chelate was found to be high in neutral and acidic solutions. Only a very small fraction (0.1 to 0.2%) of total Fe could be extracted from blood powder by a 0.1M calcium chloride (CaCl₂) solution. In the culture solution study, Fe from blood powder was as effective as Fe from FeEDDHA in preventing Fe chlorosis of soybeans. Yield and Fe content of plants receiving blood powder were higher than the control and were not different from the plants receiving FeEDDHA. The incubation study using two soils, two Fe sources and three Fe rates indicated that DTPA‐Fe increased from application of 5, 10 or 15 mg of Fe as blood powder/kg in one soil (Sudan) and from application of 10 or 15 mg of Fe as blood powder/kg in the other soil (Vernamkhast). Blood powder is a suitable Fe source for hydroponically grown plants and increases Fe availability when applied to soil.     

一种定量测定水稻根系氧化力的新方法

根系氧化力大小与根表铁膜数量密切相关,铁膜以Fe3+ 形态为主。本文根据水稻根表铁膜数量,探讨了一种测定水稻根系氧化力的新方法。首先,在水稻根系所在溶液中加入定量硫酸亚铁(Fe2+),处理1天后,水稻根系将一部分Fe2+ 氧化成Fe3+,剩余Fe2+ 用H2O2滴定,得滴定值A。然后,用H2O2滴定没有种植水稻的硫酸亚铁溶液,得滴定值B。根据不种植与种植水稻H2O2的消耗量,滴定值之差(B-A),即为水稻根系氧化力。该方法要求Fe2+ 浓度大于0.8 mmol/L,过氧化氢消耗量与Fe2+ 浓度成正比(R2 = 0.999 2)。测定过程中,应先加显色剂邻菲罗啉,然后加入磷酸。该方法在不损伤水稻根系情况下可定量测定水稻根系氧化力。     

Tissue iron distribution and urinary mineral excretion vary depending on the form of iron (FeSO4 or NaFeEDTA) and the route of administration (oral or subcutaneous) in rats given high doses of iron

Sodium iron ethylenediaminetetraacetate (NaFeEDTA) has considerable promise as an iron fortificant in food. However, effects of administering high levels of NaFeEDTA on tissue iron distribution and mineral excretion are not well understood. The objectives of this study were to assess nonheme iron distribution in the body and urinary excretion of Ca, Mg, Cu, Fe, and Zn after daily administration of high levels of iron to rats over 21 days. Iron was either given orally with food or injected subcutaneously, as either FeSO 4 or NaFeEDTA. Selected tissues were collected for nonheme iron analysis. Estimated total body nonheme iron levels were similar in rats fed NaFeEDTA or FeSO 4, but the tissue distribution was different: it was 53% lower in the liver and 86% higher in the kidneys among rats fed NaFeEDTA than among those fed FeSO 4. In contrast, body nonheme iron was 3.2-fold higher in rats injected with FeSO 4 than in rats injected with NaFeEDTA. Administering NaFeEDTA orally elevated urinary Cu, Fe, and Zn excretion compared with FeSO 4 (1.41-, 11.9-, and 13.9-fold higher, respectively). We conclude that iron is dissociated from the EDTA complex prior to or during intestinal absorption. A portion of intact FeEDTA may be absorbed via a paracellular route at high levels of intake but is mostly excreted in the urine. Metal-free EDTA may be absorbed and cause elevated urinary excretion of Fe, Cu, and Zn.     

Using Low-Cost Iron Byproducts from Automotive Manufacturing to Remediate DDT

Water, soil and sediment contaminated with DDT poses a threat to the environment and human health. Previous studies have shown that zerovalent iron (ZVI) can effectively remediate water contaminated with pesticides like DDT, metolachlor, alachlor. Because the type of iron can significantly influence the efficiency and expense of ZVI technology, finding a cheaper and easily available iron source is one way of making this technology more affordable for field application. This study determined the effects of iron source, solution pH, and presence of Fe or Al salts on the destruction of DDT. Batch experiments demonstrated successful removal of DDT (>95% in 30 d) in aqueous solutions by three different iron sources with the following order of removal rates: untreated iron byproduct (1.524 d^?1) > commercial ZVI (0.277 d^?1) > surface-cleaned iron byproduct (0.157 d^?1). DDT removal rate was greatest with the untreated iron byproduct because of its high carbon content resulted in high DDT adsorption. DDT destruction rate by surface-cleaned iron byproduct increased as the pH decreased from 9 to 3. Lowering solution pH removes Fe (III) passivating layers from the ZVI and makes it free for reductive transformations. By treating DDT aqueous solutions with surface-cleaned iron byproduct, the destruction kinetics of DDT were enhanced when Fe(II), Fe(III) or Al(III) salts were added, with the following order of destruction kinetics: Al(III) sulfate > Fe(III) sulfate > Fe(II) sulfate. Cost analysis showed that the cost for one kg of surface-cleaned iron byproduct was $12.33, which is less expensive than the commercial ZVI. Therefore, using surface-cleaned iron byproduct may be a viable alternative for remediating DDT-contaminated environments.     

Theoretical speciation of ethylenediamine-N-(o-hydroxyphenylacetic)-N'-(p-hydroxyphenylacetic) acid (o,p-EDDHA) in agronomic conditions

The presence of ethylenediamine-N-(o-hydroxyphenylacetic)-N'-(p-hydroxyphenylacetic) acid (o,p-EDDHA) as the second largest component in commercial EDDHA iron chelates has recently been demonstrated. Here is reported the speciation of o,p-EDDHA by the application of a novel methodology through the determination of the complexing capacity, protonation, and Ca(2+), Mg(2+), Cu(2+), and Fe(3+) stability constants. The pM values and species distribution in solution, hydroponic, and soil conditions were obtained. Due to the para position of one phenol group in o,p-EDDHA, the protonation constants and Ca and Mg stability constants have different values from those of o,o-EDDHA and p,p-EDDHA regioisomers. o,p-EDDHA/Fe(3+) stability constants are higher than those of EDTA/Fe(3+) but lower than those of o,o-EDDHA/Fe(3+). The sequence obtained for pFe is o,o-EDDHA/Fe(3+) >/= o,p-EDDHA/Fe(3+) > EDTA/Fe(3+). o,p-EDDHA/Fe(3+) can be used as an iron chelate in hydroponic conditions. Also, it can be used in soils with limited Cu availability.