Assessment of dietary exposure of young Chinese children to aluminium residues

Effects of Subchronic Aluminum Exposure on Learning, Memory, and Neurotrophic Factors in Rats

Aluminum (Al) is a neurotoxin that gradually accumulates in the brain in human life, resulting in oxidative brain injury related to Alzheimer's disease (AD) and other diseases. In this study, the learning and memory of rats exposed to different aluminum concentrations (0.0 g/L, 2.0 g/L, 4.0 g/L, and 8.0 g/L) were studied, and the learning and memory of rats were observed by shuttle box experiment. With hematoxylin and eosin staining, Western blot, immunofluorescence, and RT-PCR, the morphology of nerve cells in the hippocampus of rat brain were observed, and the levels of activator protein-1 (AP-1) gene and protein, nerve growth factor (NGF), neurotrophin-3 (NT3), glial cell line-derived neurotrophic factor (GDNF), and brain-derived neurotrophic factor (BDNF) gene and protein level, etc. The experimental results showed that subchronic aluminum exposure damaged learning and memory in rats. The cognitive function damage in rats was more evident after increasing the aluminum intake dose. The more aluminum intake, the more pronounced the histological changes in the hippocampus will be. The expression level and protein content of neurotrophic factors in the hippocampus of rats showed a negative correlation with aluminum intake. In this experiment, we explored the mechanism of aluminum exposure in learning and memory disorders, and provided some data reference for further elucidation of the damage mechanism of aluminum on the nervous system and subsequent preventive measures.

Survey of six metal contaminants and impurities and eleven metals and alloy components released from stainless-steel sheets on the Chinese market

The release of metal elements from stainless-steel products in contact with food may endanger human health. To protect human health, different countries or international organisations have formulated corresponding regulations or technical guidelines. Limits for only five metal elements are stipulated in the China National Food Safety Standard (GB 4806.9) and food simulants and test conditions are fixed regardless of the actual use condition. In this study, inductively coupled plasma mass spectroscopy and inductively coupled plasma optical emission spectroscopy were used to measure the concentrations of six metal contaminants and impurities and 11 metals and alloy component released from stainless-steel sheets on Chinese market. The effects were also investigated on metal release of six grades (201, 202, 304, 430, 443, and 30Cr13) and 6 exposure conditions (food simulant 5 g L^-1 citric acid or 4 vol% acetic acid, contact temperature 70 °C or 100 °C, and contact time 2 h, 0.5 h, or 0.5 h followed by ambient temperature for 24 h). For reusable stainless-steel sheets, especially for grade 30Cr13, it was essential to perform three consecutive release tests to check compliance. However, there was no need to conduct three consecutive release tests for the other five grades if the results of the first test met the regulations. It was recommended that 5 g L^-1 citric acid should be used as food simulant and contact temperature and time should be based on the actual using conditions. No relationships were found between metal release amounts and contact test temperature or time. The specific release limits for Pb, Cr, As, Cd, and Ni should be lowered and Al, Mn, and Fe be added in GB 4806.9. The results of this study can be a reference for further analysis of the release behaviour of metal elements in actual stainless-steel products.

Monitoring of Aluminum content in food and assessment of dietary exposure of residents in North China

Although the Chinese diet has become very abundant in the past 30 years, few people know that traditional Chinese diet is exposed to aluminium (Al). A total of 1232 samples were purchased during 2017-2019 and analysed for Al content with an inductively coupled plasma-mass spectrometry (ICP-MS) method. High Al levels were found in deep-fried dough sticks (mean 219 mg/kg), starch products (mean 84.5 mg/kg), and steam bread (mean 28.6 mg/kg). The average dietary Al exposure of residents in North China was 1.82 mg/kg bw/week, lower than the PTWI (provisional tolerable weekly intake). Deep-fried dough sticks (DFDS) are the main Al contributor in North China, providing 28.2% of the daily intake. The P95 dietary exposure to Al from DFDS was 2.3 mg/kg bw/week, exceeding the PTWI. Therefore, more attention should be paid to the health risk of exposure to Al from DFDS and starch products. Over-use of Al associated with food additives should be effectively controlled.

Attempt of Bayesian Estimation from Left-censored Data Using the Markov Chain Monte Carlo Method: Exploring Cr(VI) Concentrations in Mineral Water Products

Hexavalent chromium (Cr(VI)) is toxic, carcinogenic, and mutagenic substances. Oral exposure to Cr(VI) is thought to be primarily from drinking water. However, under the certain reporting limit (~0.1 µg/L), percentage of Cr(VI) concentration in mineral water products under the reporting limit were estimated higher than 50%. Data whose values are below certain limits and thus cannot be accurately determined are known as left-censored. The high censored percentage leads to estimation of Cr(VI) exposure uncertain. It is well known that conventional substitution method often used in food analytical science cause severe bias. To estimate appropriate summary statistics on Cr(VI) concentration in mineral water products, parameter estimation using the Markov chain Monte Carlo (MCMC) method under assumption of a lognormal distribution was performed. Stan, a probabilistic programming language, was used for MCMC. We evaluated the accuracy, coverage probability, and reliability of estimates with MCMC by comparison with other estimation methods (discard nondetects, substituting half of reporting limit, Kaplan-Meier, regression on order statistics, and maximum likelihood estimation) using 1000 randomly generated data subsets (n = 150) with the obtained parameters. The evaluation shows that MCMC is the best estimation method in this context with greater accuracy, coverage probability, and reliability over a censored percentage of 10-90%. The mean concentration, which was estimated with MCMC, was 0.289×10-3 mg/L and this value was sufficiently lower than the regulated value of 0.05 mg/L stipulated by the Food Sanitation Act.

Assessment of exposure to toxic metals and measures to address deficiency of essential trace elements in young children in rural Hubei, China

Children are exposed to toxic metals via diet and environment, which results in adverse health effects. Several trace elements are important for the nutritional status of children; however, little information is available for rural regions in Asia. Our goal was to assess the body burden of lead, cadmium, and aluminum (Al) as toxic metals and calcium (Ca), zinc, copper, selenium (Se), strontium, and boron as trace elements in children. Multiple environmental samples, including soil, dust, fine particulates, drinking water, and food, were collected for each family. A survey was conducted by trained personnel to record detailed information about children attending a rural school. Twenty-four-hour urine samples were collected. The levels of toxic and essential trace elements were determined by inductively coupled plasma mass spectrometry. We found that the daily intake of toxic metals was below the recommended maximum, suggesting low health risks. More attention should be given to the ingestion of Al by the hand-to-mouth pathway. Ca deficiency was discovered to be a serious health problem for rural children, with Ca inadequacies reaching 96%. The excessive intake of Se-rich products from industry suggests an increased risk of toxicity. This study highlights the health risks to children who live in rural regions and the importance of dietary Ca supplementation in school meals.