Interannual variation and exposure risk assessment of lead in brick tea in Hubei, China.

Lead (Pb) exposure may cause severe health outcomes such as decreased fertility, joint pain and neurological disorders. It is important to know the Pb exposure level in tea and the risk assessment for local residents who drink brick tea daily. This study detected sixteen brick tea samples over 26 years and fifteen green tea samples in 2011 in a southeast city of Hubei province. The Pb content in brick tea was found to increase rapidly with the fast development of industrial activities represented by car sales from 1985 to 2011, which was less susceptible to gasoline. The concentrations of Pb in 16 brick tea were in the range of 1.77-17.8 mg/kg with a mean value of 11.1 mg/kg. Their percentiles P50, P90, and P95 were 13.22, 16.95, and 17.21 mg/kg. A regressional model was built, suggesting strong correlation between the Pb content in brick tea and the car sales. The concentrations of Pb in 15 green tea samples were between 0.36-1.30 mg/kg with a mean value of 0.66 mg/kg and the percentiles P50, P90, and P95 were 0.62, 1.05, and 1.23 mg/kg. The MOE values of brick tea and green tea were all greater than 1 just considering tea consumption which displayed low Pb exposure risk. By adding the Pb exposure by food, the MOE values for green tea were still greater than 1 while the MOE values of brick tea were less than 1 suggesting a potential risk of Pb exposure to the people drinking brick tea daily, who should pay more attention.

Pharmacokinetics of Sodium Selenite in Rat Plasma and Tissues After Intragastric Administration.

The purpose of this research is to investigate the absorption, distribution, excretion, and pharmacokinetics of selenite in rats after intragastric administration, and thus illustrate the efficiency of selenium (Se) supplementation. After a single gavage of sodium selenite, a concentration of Se in plasma and tissues was determined by inductively coupled plasma mass spectrometry (ICP-MS) at different time points. Through fitting the data with the metabolic kinetic model, the corresponding kinetic parameters were determined for plasma and tissues, including kidney, liver, heart, muscle, and gonad. While the metabolic kinetics of sodium selenite in plasma, liver, and kidney of rats was well reflected by a two-compartment open model, that in heart and gonad was fitted to a one-compartment open model, and that in muscle was fitted to a one-compartment open model with a lag time. The results indicate that sodium selenite was absorbed by plasma and tissues quickly and was eliminated slowly after intragastric administration. Based on the results, we propose that multi-supplementation of Se with low dosage is superior to single supplementation with high dosage, in terms of avoiding selenosis.