Accumulation and distribution of perchlorate in spinach and chard growing under greenhouse: Implications for food safety in baby foods commodities

Perchlorate in honey from China: Levels, pollution characteristics and health risk assessment

The release and accumulation of perchlorate into the environment have raised concerns about safety to food, however, the dietary risk of perchlorate in honey have not yet received attention. Herein, we investigated the pollution characteristics and assessed the human health risks of perchlorate in honey from China. A total of 151 honey samples collected from 20 provinces of China were analyzed, and overall detection frequencies was 95.4 %. The levels of perchlorate ranged from below limit of quantitation to 612 μg/kg, with a mean value of 34.5 μg/kg. Lychee honey samples had the highest mean perchlorate concentration (163 μg/kg). The mean concentration of perchlorate in the honey samples produced in South China was significantly higher than that in honey from Southwest China, East China and North China (P < 0.05). The health risk assessment showed that mean hazard quotient (HQ) values of different honey for children (ranged from 0.0108 to 0.400) and adults (ranged from 0.0123 to 0.453) were less than 1. This result indicated that mean pollution levels of perchlorate in various honey were unlikely to pose health risk. However, perchlorate concentrations in two lychee honey samples had associated HQ values were >1, suggesting potential health risks. This work not only offers valuable information for honey consumer, but also important reference for comparison of honey samples in the future. ENVIRONMENTAL IMPLICATION: Perchlorate contamination has become a hot environmental issue in connection with human health due to its potential thyroid toxicity and widespread occurrence in environment and foods. Honey not only was widely beloved by consumers worldwide but also considered a potential indicator of environmental pollution. Here, a national investigation and risk assessment of perchlorate levels in different types of honey from China was conducted. The results describe the perchlorate contamination were extensive in honey samples, mean levels of perchlorate in various honey were unlikely to cause health risks. However, significantly high level of contamination in lychee honey should be of concern.

Freezing-assisted sugaring-out liquid-liquid extraction coupled with LC-MS/MS for quantitative determination of perchlorate in honey

For the first time, a simple, quick, sensitive, and low cost method for quantification of perchlorate in honey using liquid chromatography-tandem mass spectrometry was developed. Through freezing-assisted sugaring-out liquid-liquid extraction, one-step simultaneous extraction and clean-up of perchlorate from honey were perfectly achieved. Glucose and fructose, the most abundant sugars in honey, were almost completely removed from the extract without use of any clean-up materials. Under optimum conditions, the proposed approach exhibited satisfactory linearity, negligible matrix effects, and low detection limit of 0.05 µg/kg, providing recoveries of 96.7 %-102.3 % with relative standard deviation of < 9 % for honey samples. The validated method was applied to the analysis of perchlorate in 36 honey samples, and detection rate was 94.4 %. This work provided a simple and reliable method for extensive monitoring of perchlorate in honey and opened- up new insights for analysis of contaminants in honey matrixes.

Chlorate and perchlorate in tea leaves from major producing regions in China and related human exposure risk

Chlorate and perchlorate are emerging pollutants that may interfere with thyroid function. Since they are highly water soluble, chlorate and perchlorate in tea leaves cause health concerns but have scarcely been studied. In this study, chlorate and perchlorate concentrations in 216 tea samples from different regions of China were determined. Perchlorate was detected in all the samples with a median concentration of 44.1 μg kg-1, while the chlorate detection frequency was 15.7%. We observed regional differences in perchlorate contents in tea leaves, with the highest quantity found in the central region of China. Except for dark tea, the concentration of perchlorate in tea infusions decreased with the increased number of times the tea leaves were brewed. The hazard quotients (HQs) of chlorate and perchlorate in all the samples were less than 1, suggesting negligible health risks caused by these pollutants from tea consumption. To the best of our knowledge, this is the first study to investigate chlorate and perchlorate contamination in tea infusions by simulating brewing behavior.

Uptake, translocation and metabolism of acetamiprid and cyromazine by cowpea (Vigna unguiculata L.)

Acetamiprid (ACE) and cyromazine (CYR) are the two pesticides that are used relatively frequently and in large quantities in cowpea growing areas in Hainan. The uptake, translocation and metabolic patterns and subcellular distribution of these two pesticides in cowpea are important factors affecting pesticide residues in cowpea and assessing the dietary safety of cowpea. In this study, we investigated the uptake, translocation, subcellular distribution, and metabolic pathway of ACE and CYR in cowpea under laboratory hydroponic conditions. The distribution trends of both ACE and CYR in cowpea plants were leaves > stems > roots. The distribution of both pesticides in subcellular tissues of cowpea was cell soluble fraction > cell wall > cell organelle, and both transport modes were passive. A multiplicity of metabolic reactions of both pesticides occurred in cowpea, including dealkylation, hydroxylation and methylation. The results of the dietary risk assessment indicate that ACE is safe for use in cowpeas, but CYR poses an acute dietary risk to infants and young children. This study provided a basis for insights into the transport and distribution of ACE and CYR in vegetables and contributes to the assessment of whether pesticide residues in vegetables could pose a potential threat to human health at high concentrations of pesticides in the environment.

Exploring the destiny and distribution of thiocyanate in the water-soil-plant system and the potential impacts on human health

Endocrine disruptors like thiocyanate are some of the principal causes of chronic disorders worldwide. Prenatal and postnatal exposure to thiocyanate can interfere with normal neurological development in both fetuses and newborns. Currently, little information regarding thiocyanate levels and potential sources of exposure is available. In this study, we evaluated thiocyanate uptake and accumulation in chard and spinach grown under greenhouse conditions. Both chard and spinach are commonly used to produce baby foods. Three thiocyanate concentrations were compared: Control, T1 (30 ng mL^-1), and T2 (70 ng mL^-1). Thiocyanate accumulation depended on the concentration and exposure time. Chard was found to accumulate more thiocyanate than spinach, with leaf accumulation > stem accumulation (p < 0.0194) and maximum concentrations of 76 ng g^-1 (control), 112 ng g^-1, (T1), and 134 ng g^-1 (T2). The estimated daily intake (EDI) of thiocyanate for chard and spinach (fresh) exceeded the subchronic reference dose of 200 ng^-1 kg^-1 day^-1 and the chronic reference dose of 600 ng^-1 kg^-1 day^-1. In addition, the EDI of thiocyanate for spinach in baby food exceeded twice the chronic reference dose in the vulnerable newborn-1 year age group. However, all EDIs were lower than the lowest observed adverse effect level (LOAEL) of 1.9 × 10⁵ ng kg^-1 day^-1. Further studies are needed that increase our knowledge of thiocyanate levels and potential environmental sources to reduce opportunities for exposure, especially in vulnerable groups.

Integration of probabilistic exposure assessment and risk characterization for perchlorate in infant formula and supplementary food

Infants are the primary susceptible population to perchlorate exposure-related adverse health effects, while information on their dietary intake of perchlorate via infant food remains limited. This study determined perchlorate in six categories of baby food commodities commonly consumed by 0-36 months infants. A probabilistic approach with Monte Carlo simulation was used to estimate perchlorate's daily intake (EDI) considering uncertainty and variability. Results showed that the average perchlorate concentration in infant food ranged from 3.42 to 22.26 μg/kg. The mean (SD) EDIs of perchlorate were 0.42(0.20), 0.62(0.20), and 0.46(0.14) μg/kg-bw/day for 0-6, 7-12, and 13-36-months infants, respectively. Infant formula was the major contributor (34%-74%) to EDIs of perchlorate in all age groups. Probabilistic risk characterization showed the cumulative probability of EDIs exceeding the RfD (0.70 μg/kg-bw/day) were 6.5%, 37.9%, and 4.5% for 0-6, 7-12, and 13-36-months infants, respectively. The cumulative risk of perchlorate exposure from different infant food intake should be noted.