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.

Quantification of Chlorate and Perchlorate in a Broad Range of Food Commodities, Including Baby Food, Nutritional Formulas, and Ingredients by LC-MS/MS: First Action AOAC 2022.06.

BACKGROUND: Chlorate is an effective herbicide, but also a byproduct of chlorinating agents used to disinfect water, which is one of the reasons why it is regularly found in food. Perchlorate is a ubiquitous contaminant, which is naturally occurring in the environment but also released from anthropogenic sources such as the industrial use of certain natural fertilizers. Chlorate affects the hematological system, and perchlorate the thyroid. OBJECTIVE: Implement and validate a simple and robust analytical method for the accurate determination of chlorate and perchlorate in baby food, infant and adult formulas, and ingredients thereof, which is suited for its application in routine environments where a broad variety of food commodities must be analyzed simultaneously. METHOD: Typically, analytes are extracted with a mixture of water, acidified methanol, and dichloromethane. Optionally, for dairy products and byproducts, extraction can be performed with water, acidified methanol, and EDTA, followed by two steps of cleanup (freezing out and dispersive solid-phase extraction with C18 in acetonitrile). Quantitative determination is carried out by isotopic dilution liquid chromatography tandem mass spectrometry (LC-MS/MS). RESULTS: The method was single-laboratory validated in five Nestlé Quality Assurance Centers (NQACs) in a comprehensive range of representative matrixes of different categories such as baby foods, infant/adult formulas, and ingredients, with results generally in agreement with the acceptance criteria of the Standard Method Performance Requirement (SMPR®) 2021.001 defined by AOAC INTERNATIONAL, in terms of representative matrixes validated, LOQs, trueness, and precision.The data generated during validation show that the method proposed is simple, accurate and robust enough to be implemented and applied in routine environments. CONCLUSION: The data generated during validation show that the method proposed is simple, accurate and robust enough to be implemented and applied in routine environments. HIGHLIGHTS: The AOAC Expert Review Panel approved the present method as AOAC Official First Action 2022.06.

Analysis and electroanalysis of perchlorate in water and food samples: a critical review.

Perchlorate, ClO4-, with diverse applications, has become one of the major contaminants in surface and groundwater sources. This highly soluble and stable anion poses a considerable threat to human health given that it contaminates drinking water, vegetables, milk, and other contaminated food products. ClO4- can impair the thyroid function; thus, drinking water with high levels of this anion is a severe problem worldwide. However, due to the high solubility, stability, and mobility of ClO4-, its remediation and monitoring remain a major challenge. Considering the various analytical methods, including electrochemistry, each method has advantages and disadvantages in terms of detection sensitivity, selectivity, analysis time, and cost. Also, sample preconcentration and clean-up must be performed for the analysis of more complex matrices such as food and biological samples to ensure a low detection limit and selectivity. Both ion chromatography (IC) and capillary electrophoresis (CE) coupled with electrochemical detection, in addition to liquid chromatography (LC)-mass spectrometry (MS), are expected to play key roles due to their lower detection limit with excellent sensitivities and selectivity. Herein, we also discuss the perspective on various electrode materials for the detection of ClO4- regarding whether ClO4- can be measured at the lowest levels with the highest selectivity.

A review of perchlorate contamination: Analysis and remediation strategies.

Perchlorate has been categorised as a potential contaminant and researched for years, but there are still many unknowns regarding this anion's contamination impacts. In this review, the basic information about perchlorate is summarised and evaluated, including the physical-chemical properties, fate and transportation, toxicity, analysis, and remediation. Especially, recent advances on analysis and remediation are emphasised and evaluated, such as in-situ imaging analysis and on-site bio-remediation respectively. The high solubility and persistence of the perchlorate anion mean its contamination is different from others, particularly in terms of analysis and remediation that might lead to secondary contamination. The knowledge gaps are listed for future research.

[Research on the determination of the limit value of perchlorate in the "Standards for Drinking Water Quality（GB5749-2022）" in China].

Perchlorate is an environmental pollutant that has been a focus of attention in recent years. It has been detected in many environmental water bodies and drinking water in China, with a high level of presence in some areas of the Yangtze River Basin. The human body may ingest perchlorate through exposure pathways such as drinking water and food, and its main health effect is to affect the thyroid's absorption of iodine. The "Standards for Drinking Water Quality" (GB5749-2022) includes perchlorate as an expanded indicator of water quality, with a limit value of 0.07 mg/L. This article analyzes the technical content related to the determination of hygiene standard limits for perchlorate in drinking water, including the environmental presence level and exposure status of perchlorate, main health effects, derivation of safety reference values, and determination of hygiene standard limits.

Comprehensive evaluation of perchlorate dietary exposure and health risks for Chinese adult males and breastfed infants.

Perchlorate is an environmental contaminant that has both natural and anthropogenic sources. Widespread contamination of various foods with perchlorate can be caused by water, soil, and fertilizer. Because of concerns about the health effects of perchlorate, attention has focused on its occurrence in food and potential human exposure. In this study, the dietary exposures of Chinese adult males and breastfed infants to perchlorate were evaluated using data from the sixth China Total Diet Study and the third National Breast Milk Monitoring Program conducted between 2016 and 2019. In the sixth China Total Diet Study, perchlorate was detected in 94.8 % of composite dietary samples (n = 288) from 24 provinces in China, while for the third National Breast Milk Monitoring, perchlorate was found in 100 % of pooled breast milk samples (n = 100) collected from 100 cities/counties in China. Vegetables were found to be the main source of dietary exposure for Chinese adult males. Furthermore, the concentrations in breast milk between urban (n = 34, mean: 38.6 µg/L) and rural (n = 66, mean: 59.0 µg/L) regions from 100 cities/counties in China were not significantly different. On average, the estimated daily intake of Chinese adult males (18-45 years) to perchlorate was 0.449 µg/kg bw/day, while that for breastfed infants (0-24 months) was 3.21-5.43 µg/kg bw/day. The exposure to perchlorate in breastfed infants was almost 10-fold greater than that of Chinese adult males.

Perchlorate in fine particulate matter in Shenzhen, China, and implications for human inhalation exposure.

The wide application of perchlorate in military and aerospace industries raises potential exposure risks for humans. Previous studies have mainly focused on perchlorate in drinking water, foodstuffs and dust, while its exposure in fine particulate matter (PM2.5) has received less attention. Thus, we investigated its concentrations and temporal variability in PM2.5 from October 2020 to September 2021 in Shenzhen, southern China. We also assessed the native population's intake and uptake of perchlorate in PM2.5 via inhalation. Measured PM2.5 concentrations in samples from Shenzhen ranged from 2.0 to 91.9 µg m-3. According to air quality guidelines proposed by the World Health Organization, 12.7% of all the samples exceeded interim target 1 (> 35 µg m-3), and only 37.3% met interim target 3 (< 15 µg m-3). Logistic regression analysis showed that perchlorate concentrations positively correlated with the PM2.5 concentrations and negatively correlated with precipitation. The median estimated daily intake (EDI) was highest for infants (0.029 ng kg-1 day-1), and both EDIs and estimated daily uptakes (EDUs) gradually decreased with age. All the EDIs and EDUs were below the reference dose provided by the US National Academy of Sciences (NAS), indicating that exposure to perchlorate in PM2.5 posed negligible health risks for Shenzhen residents. However, the exposure of infants and specific groups who tend to be more highly exposed than average still warrants attention.

Coremoval of Energetics and Oxyanions via the In Situ Coupling of Catalytic and Enzymatic Destructions: A Solution to Ammunition Wastewater Treatment.

Ammunition wastewater contains toxic nitrated explosives like RDX and oxyanions like nitrate and perchlorate. Its treatment is challenged by low efficiency due to contaminant recalcitrance and high cost due to multiple processes needed for separately removing different contaminant types. This paper reports a H2-based low-energy strategy featuring the treatment of explosives via catalytic denitration followed by microbial mineralization coupled with oxyanion reduction. After a nitrate- and perchlorate-reducing biofilm incapable of RDX biodegradation was coated with palladium nanoparticles (Pd0NPs), RDX was rapidly denitrated with a specific catalytic activity of 8.7 gcat-1 min-1, while biological reductions of nitrate and perchlorate remained efficient. In the subsequent 30-day continuous test, >99% of RDX, nitrate, and perchlorate were coremoved, and their effluent concentrations were below their respective regulation levels. Detected intermediates and shallow metagenome analysis suggest that the intermediates after Pd-catalytic denitration of RDX ultimately were enzymatically utilized by the nitrate- and perchlorate-reducing bacteria as additional electron donor sources.

Research on the determination of the limit value of perchlorate in the "Standards for Drinking Water Quality（GB5749-2022）" in China / 中华预防医学杂志

Perchlorate is an environmental pollutant that has been a focus of attention in recent years. It has been detected in many environmental water bodies and drinking water in China, with a high level of presence in some areas of the Yangtze River Basin. The human body may ingest perchlorate through exposure pathways such as drinking water and food, and its main health effect is to affect the thyroid's absorption of iodine. The "Standards for Drinking Water Quality" (GB5749-2022) includes perchlorate as an expanded indicator of water quality, with a limit value of 0.07 mg/L. This article analyzes the technical content related to the determination of hygiene standard limits for perchlorate in drinking water, including the environmental presence level and exposure status of perchlorate, main health effects, derivation of safety reference values, and determination of hygiene standard limits.

Monitoring and risk assessment of perchlorate in tea samples produced in China.

Accumulation of potentially perchlorate in tea is a new concern for tea consumers. The information on perchlorate contamination in tea is highly limited. This study aimed to investigate the occurrence and accumulation of perchlorate in tea samples from China and to assess human exposure risks. A total of 288 tea samples collected from 16 provinces of China were tested, and nearly 94.8% of the samples were found to have detectable perchlorate contamination. Concentrations of perchlorate ranged from below LOQ to 1274.3 µg/kg, with a mean value of 294.6 µg/kg. Tea samples collected from Central China had the highest mean perchlorate concentration (403.4 µg/kg). The mean and median perchlorate levels in the dark and black samples were much higher than that of other types of tea samples. After brewing tea, the dissolution rates of perchlorate from the dried tea ranged from 58.9% to 89.2%. For the worst-case scenario, the estimated daily intakes (EDIs) of tea samples in 16 investigated provinces ranged from 25.9 to 157.8 ng/kg bw/day and 29.7-180.7 ng/kg bw/day for male and female respectively, indicating no significant health risks to local residents via tea consumption.

Visual detection of perchlorate in aqueous solution using alkali methylene blue.

Perchlorate (ClO4-) has aroused wide concern as a global ecosystem pollutant, especially in the aquatic environment. A rapid and visible detection of ClO4- in aqueous solution using alkali methylene blue (MB) and liquid-liquid extraction (LLE) was established with high selectivity and sensitivity. The alkali MB exclusively change from red into blue in an organic solvent when exposed to aqueous ClO4-. The organic solvent, amount of MB and the alkalinity of the solution were systematically optimized, while the underlying mechanism was revealed using UV-Vis spectroscopy and mass spectrometry. Under the optimum conditions, the UV-Vis absorbance at 600 nm showed a good linear relationship with the concentrations of ClO4- in the range of 0.0025-0.025 mM (R2 = 0.9945). The visual detection limit was 0.005 mM in environmental water and 0.02 mM in black tea infusion. This method provides an economical and simple visual detection of ClO4- in an aqueous solution.

Chlorate and perchlorate residues in food products on the Danish market.

Upon the European commission's request in 2013, Denmark initiated a survey of the levels of chlorate and perchlorate in agriculture products from the Danish market over a period of 4 years from 2014 to 2017. The results of the survey were used to guide decision making with a view to setting maximum levels for intra-Union trade in 2013 and reviewing and updating the levels from 2020. The results of the Danish survey and the employed analytical method are documented in this paper. In addition to the 89 domestic samples, 30 samples of foreign origin were analysed for chlorate and perchlorate, together with ten samples of baby food and seven samples of infant formula collected from the Danish market. Samples were extracted using the Quick Polar Pesticides extraction method (QuPPe) and analysed on a triple quadrupole LC-MS/MS system. The levels of both chlorate and perchlorate detected in samples originating from Denmark were lower than the current MRLs except for a single sample of lettuce. Moreover, the percentage of foreign samples that were positive for chlorate and perchlorate residues was higher than the percentage of domestic samples. The reason for the generally low levels and low frequency of chlorate and perchlorate in Danish products is most likely linked to the fact that the water supply in Denmark is 100% unchlorinated ground water. The present study shows that residues of perchlorate and chlorate are found in Danish food products at a relatively low frequency and that the levels found are below the EU's MRLs implemented in 2020.

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

Very little information is available with regards to the bioavailability of perchlorate in spinach or chard used in the production of baby foods commodities. In the present study, the uptake and accumulation of perchlorate were compared under two different treatments (T1: 1 and T2: 10 mg L-1 ClO4-). Our results indicate that spinach has a higher capacity to accumulate perchlorate than chard (p < 0.0185). Concentrations of perchlorate in leaves, stems and roots (leaves > stem > roots) all gradually increased (p < 0.0001) as vegetable growing and treatment (T2 > T1). No significant differences were found between the control and T1. The daily intake for perchlorate (control) is below the proposed international standard, however, it was exceeded in T1 and T2. The results suggested that perchlorate is actively accumulate in high concentrations in vegetables used in the production of baby food commodities and the exposure of perchlorate via the food consumption (baby foods) was evaluated as not safe.

The contamination and estimation of dietary intake for perchlorate and chlorate in infant formulas in China.

The contents of perchlorate and chlorate were determined in a total of 278 samples of infant formulas marketed in China. The associated health risk via infant and young child formulas consumption for 0-36 month old children in China was also assessed. The contents of perchlorate and chlorate were measured by a validated method with LC-MS and the limit of detection (LOD) was 1.5 µg kg-1 and 3.0 µg kg-1 for perchlorate and chlorate, respectively. Perchlorate and chlorate were detected in about 85.8% (median 6.92 µg kg-1, maximum 74.20 µg kg-1) and 99.3% (median 52.80 µg kg-1, maximum 2780 µg/kg) of the samples. The exposures of infant and young children to perchlorate from formulas were lower than the provisional maximum tolerable daily intake (PMTDI, 0.7 µg/kg bw/day), which was established by U.S. Environmental Protection Agency (EPA). The European Food Safety Authority (EFSA) in 2015 also proposed a tolerable daily intake (TDI) of 3 µg/kg bw/day for chlorate based on the mean and average concentrations. Only for infants 0-6 month at the 95th percentile did exposures exceed the TDI of 3 µg/day for chlorate. Therefore, the safety of infant and young child formulas is excellent. To our knowledge, this is the first report to assess the exposure of infant and young child formulas in China to perchlorate and chlorate.

Perchlorate in shellfish from South China Sea and implications for human exposure.

Shellfish can absorb and accumulate contaminants. The consumption of shellfish could expose humans to pollutants and increase related health risk. Perchlorate (ClO4-) is a ubiquitous pollutant and could affect thyroid functions, especially for children and pregnant women. However, knowledge on the contamination of perchlorate in aquatic food such as shellfish remains limited. This study aimed to investigate the abundances of perchlorate in shellfish from South China Sea and to assess human exposure risks. A total of 178 shellfish samples from eight species were collected from offshore aquaculture waters in South China Sea. Perchlorate was detected in 99.4% of them, suggesting widespread pollution in coastal waters. Concentrations of perchlorate ranged from not detected (N.D.) to 71.5 µg kg-1, with a median value of 4.33 µg kg-1. Estimated daily intake (EDI) and hazard quotient (HQ) were used to assess human exposure dose and health risks, respectively. The HQ values were determined to be less than 1, indicating no significant health risks to local residents via shellfish consumption. To our knowledge, this is the first study to investigate perchlorate contamination in South China shellfish and assess potential human risks.

Biosynthesized silver nanoparticle-coated electro-membrane extraction of perchlorate in different seafood samples.

In this work we developed a rapid and straightforward technique in which biosynthesized silver nanoparticles (Ag-NPs) were coated on a porous membrane utilizing electrical potential to extract perchlorate from seafood samples. The biosynthesized Ag-NPs were well characterized using UV-Vis. spectrophotometry, X-ray diffraction, and scanning electron microscopy. After extraction, analyses were performed using ion chromatography. The Ag-NP-coated porous polypropylene membrane shows higher extraction efficiency due to the high electrical conductivity of the Ag-NPs. The performance of this efficient technique was compared with those previously reported in the literature. The extraction variables that affect extraction of the target analyte and influence percentage recovery, such as pH of the sample solution, extraction time, and applied voltage, were investigated and optimized. The results demonstrated optimum conditions to achieve low detection limits [LODs (limits of detection)]: sample solution (pH = 6), short extraction time (10 min), and applied voltage (5 V). The developed method shows excellent linearity for perchlorate ion in the range from 0.001 to 350 µg L-1 with a coefficient of determination (r2 ) of 0.9991. The detection limit (LODs) and quantification limits (limits of quantification) were found to be 0.04 and 0.1225 µg kg-1 , respectively. The mean recovery percentages for three replicates of 10 different spiked fish samples by 3 µg g-1 of perchlorate were between 92.2 and 106.2%, with an observed relative standard deviation in the range of 0.8-3.7%. The proposed method is rapid, sensitive, inexpensive, environmentally friendly, and highly effective in extracting perchlorate from different seafood samples.

Dietary exposure and risk assessment of perchlorate in diverse food from Wuhan, China.

The perchlorate levels in 330 foods belonging to 5 varieties obtained from Wuhan were monitored. An ultra-high performance liquid chromatography coupled with triple quadrupoles mass spectrometry in combination with Cl18O4- internal standard method was performed to determine the level of perchlorate in various foods. Hereafter, dietary exposure and risk assessment of perchlorate was evaluated. The results revealed that the average level of perchlorate was 15.04 µg/kg with a detection of 95% among the whole food groups. The level of perchlorate in vegetables was the highest among the 5 varieties of food with an average content of 27.39 µg/kg, which in meat was the lowest with an average of 3.65 µg/kg. Estimated dietary intake results illustrated that males showed exposure in the range 0.004-0.18 µg/kg bw/day, which for females was 0.01-0.21 µg/kg bw/day. The results indicated that exposure to perchlorate via the food consumption for Wuhan people was evaluated as safe.

Perchlorate occurrence in foodstuffs and water: Analytical methods and techniques for removal from water - A review.

Perchlorate (ClO4-), a type of contaminant with high diffusivity and durability, has been widely detected in water and foodstuffs, arousing a global concern. It can interfere with normal function of the human thyroid gland, affecting human health. Therefore, determination of perchlorate in water and foodstuffs, and removal from water are important. This review focuses on the occurrence of perchlorate, mainly in water and foodstuffs, and provides an overview of analytical methods for determination of perchlorate over the last two decades. In addition, merits and drawbacks of the various methods have been considered. This review also highlights the most commonly used approaches for removal of perchlorate from water. Finally, current trends and future perspectives in determination of perchlorate and removal from water are proposed. This review provided a comprehensive understanding of perchlorate occurrence and its removal from water, and had practical significance in reducing the harm of perchlorate to human.

Rapid Cleanup of a Perchlorate Plume from Fireworks.

Perchlorate was detected in a municipal wellfield in Evart, Michigan in April 2015. Perchlorate concentrations were detected initially in six of the City's wells at concentrations ranging up to 20 µg/L. An investigation to identify the source determined that the perchlorate was from fireworks launched during the annual 4th of July show held at the fairgrounds located upgradient from the wellfield. The use of approximately 600 kg of fireworks during the annual display resulted in an annual loading of approximately 4 kg of perchlorate to groundwater. An aggressive groundwater extraction system began operation in June 2016 to restore water quality in the affected aquifer, and the 2016 fireworks display was relocated to a location outside the capture zone of the water supply wells. Within 18 months average perchlorate concentrations in the water supply wells had been reduced to about 0.6 µg/L. The extraction system continued to operate through the end of 2019, by which time the average perchlorate concentrations in the water supply wells were reduced to 0.2 µg/L. In 2019, approximately 0.4 kg of perchlorate were removed from the aquifer, about one-half of the amount removed in 2018, reflecting the slow leaching of perchlorate of fireworks residuals from vadose zone soils.

Extension of shelf life of semi-dry longan pulp with gaseous chlorine dioxide generating film.

A packaging system using gaseous chlorine dioxide generating film (CDGF) in a sealed container was developed to extend the shelf life of semi-dry longan pulp (moisture content 38.8 wt%; aw0.8). The antimicrobial properties, formation of chloroxyanion residues and effects of CDGF on the quality of semi-dry longan pulp were investigated. CDGF was triggered by the moisture vapor from semi-dry longan pulp in the sealed container and released gaseous ClO2 into the headspace of the container. The antifungal test showed that CDGF significantly inactivated artificially inoculated molds in semi-dry longan pulp and achieved reductions of over 3 log CFU/g after 28 days storage at room temperature (25 °C). CDGF reduced total aerobic bacterial populations by over 6.4 log CFU/g and maintained these population levels at around 2.0 log CFU/g throughout the 180-day storage period at room temperature. The residual concentrations of chloride, chlorate and perchlorate in longan pulp increased and then decreased during the 180-day storage. Residual chloride levels were maintained at 1.5 mg/g after Day 120 and residual chlorate and perchlorate levels were not detected after Day 120 and Day 180, respectively, in CDGF-treated samples. CDGF treatments reduced total polyphenol content but didn't have any significant impact on the levels of polysaccharides in samples. There were no significant differences between CDGF-treated and control samples in color changes during storage. The content of 5-hydroymethylfurfural (5-HMF) in both samples increased during storage, suggesting that the Maillard reaction occurred. This study demonstrated an effective approach to develop a new antimicrobial packaging system for semi-dry longan pulp.