Search Results

You are looking at 11 - 19 of 19 items for

  • Author or Editor: E. De Nadai Fernandes x
  • Refine by Access: All Content x
Clear All Modify Search

Summary  

Trace elements were determined in 27 brands of nail polish using INAA so as to estimate the impact of nail polish remainders when using (finger, toe) nail clippings as a bioindicator for epidemiological studies. Fe was found to be present up to almost 1.7% in one brand. No unambiguous correlation between trace elements and color was established, though transparent polish has the lowest trace element concentrations. An estimate of the maximum effect (no removal of the paint) indicates that over-estimates of some trace element levels in nail with more than 200.000% may occur. This study showed that if nail clippings will be used to study trace elements, very high demands have to be set to the efficiency and selectivity of the cleaning procedure.

Restricted access

Abstract  

The elemental composition of potato tubers from four varieties growing in an experimental field under conventional and organic conditions was investigated. Br, Co, K, Na, Rb and Zn, determined by k 0-instrumental neutron activation analysis, were used to distinguish the tubers according to the cultivation system. The difference between organic and conventional potatoes was evidenced by cluster analysis, specially using Br, Co, K and Rb.

Restricted access
Journal of Radioanalytical and Nuclear Chemistry
Authors:
F. Tagliaferro
,
E. De Nadai Fernandes
,
M. Bacchi
,
P. Bode
, and
E. Joacir De França

Abstract  

Depending on the harvest conditions, coffee beans can be contaminated by soil when dropped to the ground. It is well known that agricultural soils act as sinks for agrochemicals applied to the crops. While coffee is brewed, substances present in the roasted and ground coffee beans are extracted by hot water, emphasizing the need to assess the possible transfer of impurities from the soil to the beverage. Soil-contaminated samples of roasted coffee beans were split into 2 groups according to the treatments: (a) washed and ground and (b) only ground. Brewing was performed in a household espresso machine for both coffees. The resulting beverage was freeze-dried and the elemental composition determined by instrumental neutron activation analysis (INAA). The mass fractions of the terrigenous elements Fe, La, Sc, Sm and Th in the freeze-dried non-washed coffee beverages were, at least, 2 times higher than in the washed samples. These elements are tracers of the soil, indicating that the impurities from the soil reached the beverage.

Restricted access
Journal of Radioanalytical and Nuclear Chemistry
Authors:
E. Joacir De França
,
E. De Nadai Fernandes
,
M. Bacchi
,
F. Tagliaferro
, and
M. Saiki

Abstract  

Soil analysis could improve environmental studies since soil is the main source of chemical elements for plants. In this study, soil samples collected at 0–10 cm depth under tree crown projection were analyzed by INAA. Using the chemical composition of the leaf previously determined, the leaf-soil transfer factors of chemical elements could be estimated for the Atlantic Forest. Despite the variability of the intra-species, the transfer factors were specific for some plant species due to their element accumulation in the leaves. Similar Br-Zn combined transfer factors were obtained for the species grouped according to habitats in relation to their position (understory or dominant species) in the forest canopy.

Restricted access

Abstract  

The citrus variegated chlorosis (CVC) disease results in serious economical losses for the Brazilian citriculture. The influence of CVC disease on the elemental composition of citrus plants was investigated. Leaves of sweet orange varieties Hamlin, Pera Rio and Valencia were collected from healthy and CVC-affected trees for chemical characterization by instrumental neutron activation analysis (INAA). Significant differences between healthy and CVC-affected leaves were identified for Ca, Ce, Co, Eu, Fe, K, La, Na, Nd, Rb, Sc and Sm. Rare earth elements presented consistently higher mass fractions in the healthy leaves.

Restricted access

Abstract  

The effectiveness of a Compton suppression system (CSS) for instrumental neutron activation analysis of plant materials was evaluated. Suppression factors were measured with 137Cs sources. Five certified reference materials were analyzed and the detection limits calculated from both suppressed and unsuppressed spectra were compared. The CSS demonstrated to be useful for lowering the detection limits of ten out of sixteen elements tested, showing a maximum improvement factor of 3.9. The system performance was strongly influenced by the sample composition and also by the measurement conditions, indicating the importance of testing each individual sample type and analytical protocol.

Restricted access

Abstract  

Tomato is amongst the most consumed vegetables in the world, not only for its culinary versatility but also for its high nutritional value. In the last years, consumers have shown an increased concern regarding food origin and safety. The organic tomato production has been a promising alternative for the consumer offering a safer food in relation to environmental, social and nutritional aspects. This study assessed the chemical composition of tomato seeds produced in both conventional and organic systems by INAA. The results showed significant differences (p≤0.05) in the mass fractions of Br, Cs, Eu, Fe, K, Mo, Na, Rb and Sm between both systems, indicating influence of the crop management adopted in the different tomato production systems.

Restricted access

Abstract  

The agricultural supplies used in the organic system to control pests and diseases as well as to fertilize soil are claimed to be beneficial to plants and innocuous to human health and to the environment. The chemical composition of six agricultural supplies commonly used in the organic tomato culture, was evaluated by instrumental neutron activation analysis (INAA). Results were compared to the maximum limits established by the Environment Control Agency of the São Paulo State (CETESB) and the Guidelines for Organic Quality Standard of Instituto Biodinâmico (IBD). Concentrations above reference values were found for Co, Cr and Zn in compost, Cr and Zn in cattle manure and Zn in rice bran.

Restricted access
Journal of Radioanalytical and Nuclear Chemistry
Authors:
T. Martins
,
E. De Nadai Fernandes
,
A. Ferrari
,
M. Bacchi
, and
F. Tagliaferro

Abstract  

The tomato culture demands large quantities of mineral nutrients, which are supplied by synthetic fertilizers in the conventional cultivation system. In the organic cultivation system only alternative fertilizers are allowed by the certifiers and accepted as safe for humans and environment. The chemical composition of rice bran, oyster flour, cattle manure and ground charcoal, as well as soils and tomato fruits were evaluated by instrumental neutron activation analysis (INAA). The potential contribution of organic fertilizers to the enrichment of chemical elements in soil and their transfer to fruits was investigated using concentration ratios for fertilizer and soil samples, and also for soil and tomato. Results evidenced that these alternative fertilizers could be taken as important sources of Br, Ca, Ce, K, Na and Zn for the organic tomato culture.

Restricted access