Concentrations of Trace Elements in Organic Fertilizers and Animal Manures and Feeds and Cadmium Contamination in Herbal Tea (Gynostemma pentaphyllum Makino).
Thailand is predominantly an agriculture-based country. Organic farming is enlisted as an important national agenda to promote food safety and international export. The present study aimed to determine the concentrations of trace elements in commercial organic fertilizers (fermented and nonfermented) composed of pig and cattle manures available in Thailand. Pig and cattle manures as well as animal feeds were also collected from either animal farms or markets. The results were compared to the literature data from other countries. Fermented fertilizer composed of pig manure contained higher concentrations of nitrogen (N) and phosphorus (P) than fertilizer composed of cattle manure. High concentrations of copper (Cu) and zinc (Zn) were also found in fertilizers and manures. Some organic fertilizers had high concentrations of arsenic (As), cadmium (Cd), and lead (Pb). The range of As concentration in these fertilizers was 0.50-24.4 mg/kg, whereas the ranges of Cd and Pb were 0.10-11.4 and 1.13-126 mg/kg, respectively. Moreover, pig manure contained As and Cd (15.7 and 4.59 mg/kg, respectively), higher than their levels in cattle manure (1.95 and 0.16 mg/kg, respectively). The use of pig manure as soil supplement also resulted in high Cd contamination in herbal tea (Gynostemma pentaphyllum Makino; GP). The Cd concentration in GP plants positively correlated with the Cd concentration in the soil. Therefore, the application of some organic fertilizers or animal manures to agricultural soil could increase some potentially toxic elements in soil, which may be absorbed by plants and, thus, increase the risk of contamination in agricultural products.
One-Step and Nondestructive Reduction of Cr(VI) in Pork by High-Energy Electron Beam Irradiation.
Because of the wide use of chromium-containing feed, much hexavalent chromium (Cr(VI)) tends to accumulate in pork. In order to decrease the toxicity of Cr(VI)-containing pork for human beings, high-energy electron beam (HEEB) irradiation was used to reduce highly toxic Cr(VI) to low toxic trivalent chromium (Cr(III)) in lean, fat, and marbled pork. HEEB irradiation could efficiently and nondestructively reduce both free and adsorbed Cr(VI) in pork, achieving the highest reductive efficiency (RE) of 98.03%. Therein, hydrated electrons (eaq- ) and hydrogen radical (•H) generated during the irradiation process probably played key roles in the reduction. The effects of irradiation dose, initial concentration of Cr(VI), pH, temperature, salinity, and oil on the RE were investigated to obtain the optimal reduction conditions, proving the high universality of this approach. This work provides a clean and low-cost method for removing Cr(VI) from pork, which is important to ensure food safety.


PRACTICAL APPLICATION
This work describes a facile, nondestructive, and clean method for removing Cr(VI) from meat product, which may have a potential application prospect in ensuring food quality and safety.
Cadmium concentration in winter wheat as affected by nitrogen fertilization
Abstract Cadmium (Cd) is a toxic heavy metal which to a relatively large extent is ingested via wheat-based products. Conflicting results have been reported on how the application of nitrogen (N) fertilizers to winter wheat (Triticum aestivum L.) affects the Cd concentration in grain. The objectives of this study were to investigate how and to what degree application of N fertilizer affected the Cd concentration in winter wheat grain under field conditions and how consistent such effects were between sites and cultivars. Two wheat cultivars fertilized with four rates of nitrate of lime (100, 145, 190 and 235 kg N ha−1) were investigated in field trials, where the fertilizer was applied on two occasions as is common for bread wheat. In addition, data on Cd and N concentrations in grain of wheat, oats and barley from a Swedish soil monitoring programme were evaluated. In the field trials the grain Cd concentration increased with increasing N rate, irrespective of the Cd concentration in soil and grain. Each 10 kg increase in N application gave an increased Cd concentration in grain of approximately 0.001–0.003 mg kg−1. The relative increase in Cd concentration as a function of N rate varied between 6 and 14% across sites and cultivars when the N rate was increased from 145 to 175 kg N. The grain Cd concentration was also positively correlated to the grain N concentration. The data from the Swedish soil monitoring programme showed a significant positive correlation between the N and Cd concentrations in grain of winter wheat, oats and barley. A possible explanation for the increase in grain Cd concentration could be ion exchange reactions in the soil solution, where an increased concentration of the fertilizer cation Ca2+ may have caused an increased concentration of Cd2+ in soil solution and eventually in wheat grain.