Hexachlorocyclohexane chemical remediation of a contaminated site in Argentina.

This work describes the complete decontamination of three parcels of a dump site located in Lomas de Zamora county, Buenos Aires province (Argentina) heavily polluted with hexachorocyclohexane (HCH), where phytoremediation, successful in the surrounding areas, was ineffective. HCH contained in contaminated soil (10 g/kg average) was oxidized with sodium persulfate activated with citric acid chelated Fe(II). This chemical remediation process required treatment in situ in each parcel of approximately 10900 tons total of soil that were mechanically removed and initially mixed with 1750 tons of sodium persulfate. The mixture was then transferred to the excavation site, and 105 tons of ferrous sulfate and 35 tons of citric acid were finally added. The process, started in January 2011 and completed in February 2016, was very effective since chemical remediation average efficiency in the three parcels was higher than 99.99%. To the best of our knowledge this work is the first demonstration that persulfate oxidation activated with citric acid chelated Fe(II) can be successfully applied for field remediation of a relatively large area.

Hexachlorocyclohexane phytoremediation using Eucalyptus dunnii of a contaminated site in Argentina.

In 1996, a diagnostic study performed in a 16-ha field located in Buenos Aires Province (Argentina), where a chemical industry produced 1,2,3,4,5,6-hexachlorocyclohexane (HCH) from 1960 to 1978, showed contamination with HCH ranging from 10 to 20,000 mg kg-1 dry soil (706.4 mg kg-1 average). For remediation purposes, a forestation plan was put into practice in 1997 employing approximately 12,300 Eucalyptus dunnii seedlings which by 2016 where fully grown into trees that formed a forest where local fauna can be found. Midterm analysis done in 2005, when E. dunnii trees had developed into 8-10 m high trees, indicated that HCH was incorporated into leaves and logs and soil phytoremediation was progressing. Final quantitation analysis of HCH in soil performed in 2016 demonstrated that the 97.2% of the field area was effectively decontaminated with 98.1% overall average efficiency. Thus, this work is the first global example of a successful employment of E. dunnii trees for HCH phytoremediation purposes at field scale. These results may encourage other researchers to test the ability of E. dunnii to phytoremediate soils contaminated with other chlorinated compounds like polychlorinated biphenyls (PCBs), polychlorinated dibenzodioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs).

Bioavailability, absorption mechanism, and toxicity of microencapsulated iron (I) sulfate: studies in mice.

The iron compounds used for food fortification have to meet certain requisites related to their bioavailability, absorption mechanism, and toxicity, since they will be consumed by a massive population group. With these purposes, we evaluated a new product used for the iron fortification of milk and lacteous derivatives, called SFE-171, which is a ferrous sulfate, microencapsulated with phospholipids. The bioavailability studies were carried out using four groups of 30 female mice each. In two groups, we studied the absorption of ferrous ascorbate and ferrous sulfate, both in water as reference standards, which show absorptions of 13.1+/-4.9% and 13.2+/-4.3%, respectively. With the third group, we studied the absorption of ferrous sulfate in milk; its value, 7.9+/-3.2%, is significantly lower than that of the remaining groups, with a p < 0.01. The studies with SFE-171 in milk, were performed on the fourth group, with a result of 11.6+/-4.5%, demonstrating that its absorption does not differ significantly from that of the reference standards. The absorption mechanism was determined by means of in vivo self-displacement studies of the ferrous ion and the SFE-171, taking ferrous sulfate as the reference compound. For this study, 210 female mice were used, and no significant difference between the absorption mechanism of both products could be observed. Toxicity studies of the new product with regard to ferrous sulfate were carried out with two groups of 70 female mice each and two groups of 70 male mice each. The lethal dose 50% LD50 for SFE-171 and for ferrous sulfate was 1200 and 680 mg/kg for female mice and 1230 and 670 mg/kg for male mice, respectively, demonstrating that the toxicity of the first product is substantially lower than that of the reference standard. We conclude that the iron product under study has a high bioavailability, an absorption mechanism equal to that of nonhemic iron, and lower toxicity than ferrous sulfate.

A new procedure to fortify fluid milk and dairy products with high-bioavailable ferrous sulfate.

The behavior of SFE-171 used for food fortification was studied. The biological and nutritional properties of this new iron source are discussed in this work.

Bioavailability and stability of microencapsulated ferrous sulfate in fluid milk: studies in mice.

Iron deficiency is the most important nutritional problem all over the world. Fluid milk is an attractive vehicle for iron fortification, since it is a food with a high nutritional value, accessible to the whole population and easy to be given to children. Fortification of this food with iron has the disadvantage of the interaction of the iron with the constitutive elements of milk, diminishing its bioavailability and changing its sensorial properties, making it unacceptable. Nowadays, this problem can be overcome by the implementation of a new technological procedure, which consists in the microencapsulation of the ferrous sulfate with lecithin, thus avoiding the interaction of iron with the food. The absorption obtained in mice for milk-ferrous sulfate was 7.9 +/- 3.2%, while for microencapsulated ferrous sulfate-milk the result was 11.6 +/- 4.5%. Comparing these data with those obtained with the ferrous ascorbate in water 13.1 +/- 4.9% and ferrous sulfate in water 13.2 +/- 4.3%, both of them considered as reference standards, no statistically significant difference between them and the microencapsulated ferrous sulfate in milk can be observed. However, this difference becomes significant (p < 0.01) when these products are compared to the non-encapsulated ferrous sulfate in milk. On the other hand, we demonstrated that this product is stable to heat-processing (100 degrees C, 30 min) and storage at a room temperature up to 6 months that lacteous products are usually submitted to.

Bioavailability of microencapsulated ferrous sulfate in fluid milk studies in human beings.

Iron deficiency is one of the most important nutritional problems in the world. The best method to overcome this problem is the fortification of foods with highly bioavailable iron. Fluid milk is a massive consumption food with an easy access and which is generally the only food intake during the first months of life. Therefore the fortification of fluid milk with highly bioavailable iron and no detectable alterations of its sensorial characteristics was studied in the present work. This procedure was made possible using a new type of ferrous sulfate, stabilized and microencapsulated with soy lecitin (SFE-171). The iron concentration of the fortified milk is 12 mg per liter. In order to study the iron absorption from milk fortified with this product, SFE-171 was labeled with 59Fe and given to 29 volunteers with a normal iron status, each of which received an iron quantity of 3 mg in 250 ml of fluid milk. The average iron absorption was (10.2 +/- 4.7) %. This result shows that the iron given in this physicochemical form has the advantage of a high bioavailability and it is possible that this product will be the first attempt for an adequate solution of iron deficiency.

New procedure to fortify fluid milk and derivatives with iron: a comparative study in mice.

It is known that the fortification of milk and its derivatives with iron has been recognized as a worldwide necessity, since the deficiency of this element produces different metabolic disorders. With this purpose, we have studied the iron absorption in mice after the administration of fluid milk and yogurt with FeSO4, stabilized by microencapsulation with soy lecithin (SFE-171) or with FeSO4, both labeled with 59Fe, which was used in the same experimental conditions for comparative purposes. The absorption of iron is influenced by the presence of some additives which usually are ingested together with milk, such as cacao, coffee, tea, "Argentine green herbs tea or maté" or cereals. The experimental results demonstrate that the iron absorption from SFE-171 is (12.3 +/- 2.9)%, whereas that from FeSO4 is (7.7 +/- 2.7)%, this difference is highly significant at p < 0.01. In all the cases, groups of 25 mice each were used to increase the statistical robustness of the experimental results. On the other hand, it could be demonstrated that the presence of 10% w/v cacao (Nesquik) increases the iron absorption in both cases, whereas 1% w/v cacao (Nesquik) and maté has no influence on the iron absorption if SFE-171 is used. Cereals (Nestum 3 cereals), yogurt and other additives like tea and coffee, for different reasons, decrease the absorption of this element.

Early biochemical effects of an organic mercury fungicide on infants: "dose makes the poison".

Phenylmercury absorbed through the skin from contaminated diapers affected urinary excretion in infants in Buenos Aires. The effects were reversible and quantitatively related to the concentration of urinary mercury. Excretion of gamma-glutamyl transpeptidase, an enzyme in the brush borders of renal tubular cells, increased in a dose-dependent manner when mercury excretion exceeded a "threshold" value. Urine volume also increased but at a higher threshold with respect to mercury. The results support the threshold concept of the systemic toxicity of metals. gamma-Glutamyl transpeptidase is a useful and sensitive marker for preclinical effects of toxic metals.