No abstract

This study aims at proving the usefulness of multielements as provenance markers of olive oils by evaluating their source, their link with the soils and their discriminating power. Eleven elements in twenty one olive oils and their paired soils from four Tunisian producing regions were characterized. The analytical results were then combined with various chemometric methods. Principal component analysis demonstrated the predominant geochemical source of the oils elements based on their associations according to Goldshmidt rule. Even though a clear correlation couldn't be proven, a correspondence was identified between the discriminating elements for both soil and olive oil represented by Fe, Rb, Mg and Pb. Linear discriminant analysis achieved classification and prediction rates of 92.1% and 87.3%, respectively. Our study shows the validity of multielements as good markers of the provenance for olive oils and that elemental fingerprinting approach can be applied to build a Tunisian olive oils database.

The Codex Alimentarius Commission has recently adopted maximum levels for inorganic arsenic (As; in 2014) and total cadmium (Cd; in 2006) in polished rice grains to maintain food safety and to decrease the risk to human health. As rice is a staple crop in Japan and monsoon Asian countries, reducing concentrations of As and Cd in rice is an urgent matter. In flooded conditions, Cd concentration in soil solution decreases whereas As concentration increases. Therefore, we aimed to evaluate the efficiency of iron-bearing materials to decrease As concentration in soil solution and rice (Oryza sativa L.) grain under submerged cultivation, while also considering Cd concentration. In experiments conducted in paddy fields in six regions, As concentrations in the soil solution during the cultivation period decreased in the following order: control (REF) > steel converter furnace slag (SCS) > non-crystalline iron hydroxide (FH) > zero-valent iron (ZVI). The concentrations of As in brown rice were in the same order, with ZVI achieving particularly strong reduction. Cadmium concentrations were low, probably owing to submerged cultivation conditions. Application of iron-bearing materials slightly and insignificantly reduced the yields of brown rice and straw. Application of these materials did not have a significant negative impact on the quality of rice. Our data indicate that the application of iron-bearing materials effectively reduces As concentrations in soil solution and rice grains without negative effects on yield and quality, with a particularly powerful effect of ZVI which is possibly explained by arsenic sulfide formation.

We investigated the extractability of manganese (Mn) and iron (Fe) oxides from typical Japanese soils (Entisols, Inceptisols, and Andisols) by 0.5 mol L À1 hydroxylamine hydrochloride (NH 2 OH-HCl) extraction (pH 1.5; 16 h shaking at 25 C; soil:solution ratio 1:40), referred as to HH mBCR , which is Step 2 (used for the reducible fraction) of the modified BCR (Community Bureau of Reference) sequential extraction procedure. The HH mBCR procedure extracted almost all Mn oxides from the non-Andisol samples, but failed to extract a part of the Mn oxides from some Andisol samples. The procedure extracted most short-range ordered Fe oxides from non-Andisol samples, but it extracted only 7.5% and 13% of the short-range ordered Fe oxides from allophanic and non-allophanic Andisol samples, respectively. This remarkably low extractability of Fe oxides suggests that the HH mBCR method is not suitable for extracting oxide-occluded heavy metals from Andisols. Since the extraction rate of short-range ordered Fe oxides from various soils with the extractant was negatively correlated with the amounts of oxalate-and pyrophosphate-extractable Al even when the variability of the extraction pH was reduced by increasing the soil:solution ratio from 1:40 to 1:500, the extractability of Fe oxides would be negatively affected by the presence of active Al, including allophane/ imogolite, amorphous Al, and Al-humus complexes. Because these Al constituents are abundant in Andisols, they would be at least partially responsible for the lower extractability of Fe oxides by HH mBCR from Andisols.

No abstract