Scientific Opinion on the risks to public health related to the presence of perchlorate in food, in particular fruits and vegetables

Investigating the correlation of analytical data on pesticide residues in fruits and vegetables with local climatic condition

The use of pesticides is increasing steadily, and even though pesticides are essential for food security, they are known for having adverse effects on human health, and the environment. Further, as pesticides are often a reaction to pests, which are influenced by environmental conditions, the environment might influence the use of pesticides-when assuming, that the use is optimized, and adjusted to those conditions. Therefore, it would be helpful to know how environmental conditions influence the pesticide residue levels of fruits and vegetables. In this work, we investigated the correlation between residue levels of ten different pesticides and the weather parameters air temperature, maximum and minimum temperature, wind speed, precipitation, and sun hours using the Pearson correlation coefficient, linear, and polynomial regression. Also, the pesticide residue levels were analyzed regarding outliers. No correlation between the measured residue levels and the weather parameters could be found for most pesticides. However, for Acetamiprid and Fluopyram, a slight correlation between the pesticide residue levels, the air, minimum-, and maximum temperature could be found. The polynomial regression model was better suited to describe the relationship between pesticide residue levels and weather parameters than the linear regression model, but R2 was not higher than 0.069 for any model.

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.

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.

A. Jorand F, Barrière F, Etienne M. Challenges and Applications of Nitrate-Reducing Microbial Biocathodes

Bioelectrochemical systems which employ microbes as electrode catalysts to convert chemical energy into electrical energy (or conversely), have emerged in recent years for water sanitation and energy recovery. Microbial biocathodes, and especially those reducing nitrate are gaining more and more attention. The nitrate-reducing biocathodes can efficiently treat nitrate-polluted wastewater. However, they require specific conditions and they have not yet been applied on a large scale. In this review, the current knowledge on nitrate-reducing biocathodes will be summarized. The fundamentals of microbial biocathodes will be discussed, as well as the progress towards applications for nitrate reduction in the context of water treatment. Nitrate-reducing biocathodes will be compared with other nitrate-removal techniques and the challenges and opportunities of this approach will be identified.

Physiologically-based toxicokinetic model for the prediction of perchlorate distribution and its application

Perchlorate is a stable and readily transportable thyroid hormone disruptor, and prevalent exposure to perchlorate through food and drinking water has raised public concern about its health effects. The physiologically based toxicokinetic (PBTK) model as a dose prediction method is effective to predict the toxicant exposure dose of an organism and helps quantitatively assess the dose-dependent relationship with toxic effects. The current study aimed to establish a multi-compartment PBTK model based on updated time-course datasets of single oral exposure to perchlorate in rats. With adjustment of the kinetic parameters, the model fitted well the toxicokinetic characteristics of perchlorate in urine, blood, and thyroid from our experiments and the literature, and the coefficient of determination (R²) between the fitting values and the experimental data in regression analysis was greater than 0.91, indicating the robustness of the current model. The results of sensitivity analysis and daily repeated exposure simulations together confirmed its effective renal clearance. According to the distribution characteristic of perchlorate, a correlation study of internal and external exposure was conducted using urinary perchlorate as a bioassay indicator. The developed multi-compartment model for perchlorate updates important toxicokinetic data and kinetic parameters, providing analytical and modeling tools for deriving total exposure levels in the short term.

Presence of Chlorate and Perchlorate Residues in Raw Bovine Milk from Italian Farms

Chlorates and perchlorates are endocrine disruptors and emerging environmental contaminants found in various types of foods, including milk and dairy products. The presence of chlorate has been associated with the use of chlorine-based sanitizers to disinfect equipment and water used in food processing. Perchlorate, on the other hand, occurs naturally in the environment but is also released from anthropogenic sources. To protect consumers, the EU set an MRL for chlorate in milk but not for perchlorate. Considering that data on chlorates and perchlorates in this field are limited, the objective of this study was to assess the presence of these two anions in 148 samples of raw bovine milk collected from different farms of Lombardy and grouped in three different geographical zones. Chlorate was detected in 73% of the samples analyzed, at concentrations ranging from <LOQ to 18.70 μg kg−1 with an average value of 7.10 ± 5.88 μg kg−1 below the MRL; perchlorate with a frequency of 99%, in the range from <LOQ to 6.95 μg kg−1 and an average value of 4.06 ± 1.58 μg kg−1. No significant differences were detected among the three geographical zones. An evaluation of the estimated daily intake of perchlorate through milk confirmed the absence of risk for Italian consumers.

Aggregating exposures and toxicity equivalence approach into an integrated probabilistic dietary risk assessment for perchlorate, nitrate, and thiocyanate: Results from the National food monitoring study and National Food Consumption Database

Perchlorate, nitrate, and thiocyanate, namely thyroid disrupting chemicals (TDCs), are found ubiquitously in the environment, leading to broad human exposure and primary uptake through the food web and drinking water. TDCs are all competitive inhibitors of thyroid iodide uptake activity, but limited studies have assessed the cumulative risk of dietary exposure to multiple TDCs. Thus, in this study, we analyzed the individual exposure risk from 310 food samples in 11 categories, and also assessed the cumulative health risks from TDCs for the Taiwanese population using a perchlorate equivalent concentration (PEC) approach. Consequently, this study not only demonstrated the non-carcinogenic health risks from individual exposure but also highlighted that the cumulative exposure to these TDCs may adversely affect human thyroid functioning. Vegetables, livestock, fruits, and dairy products are the most susceptible to PEC exposure. We highlighted nitrate as the main contributor to PEC exposure. Finally, controlling the overall TDC concentrations from vegetables, livestock, fruits, and dairy products is emphasized in this study. This is the first study to conduct a cumulative risk assessment of dietary exposure to TDCs using the PEC approach for the Taiwanese population through probabilistic and sensitivity analyses.

Chlorate addition enhances perchlorate reduction in denitrifying membrane-biofilm reactors

Perchlorate is a widespread drinking water contaminant with regulatory standards ranging from 2 to 18 μg/L. The hydrogen-based membrane-biofilm reactor (MBfR) can effectively reduce perchlorate, but it is challenging to achieve low-µg/L levels. We explored chlorate addition to increase the abundance of perchlorate-reducing bacteria (PRB) and improve removals. MBfR reactors were operated with and without chlorate addition. Results show that chlorate doubled the abundance of putative PRB (e.g., Rhodocyclales) and improved perchlorate reduction to 23 ± 17 µg/L, compared to 53 ± 37 µg/L in the control. Sulfate reduction was substantially inhibited during chlorate addition, but quickly recovered once suspended. Our results suggest that chlorate addition can enhance perchlorate reduction by providing a selective pressure for PRB. It also decreases net sulfate reduction. KEY POINTS: • Chlorate increased the abundance of perchlorate-reducing bacteria • Chlorate addition improved perchlorate removal • Chlorate appeared to suppress sulfate reduction.

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.

Occurrence, distribution and dynamics of perchlorate in soil, water, fertilizers, vegetables and fruits and associated human exposure in Chile

Perchlorate (ClO₄^-) has been identified as a persistent environmental contaminant of concern. Perchlorate exposure is a potential health concern because it interferes with hormone production by thyroid gland. Food (fruits and vegetables) and drinking water are an important source of human exposure to perchlorate. However, little is known about the occurrence of perchlorate in Chile. The purpose of this study was to determine the occurrence of perchlorate in 145 samples (soil, drinking water, surface water, groundwater, fertilizers, fruits and vegetables) collected across Chile and estimate associated exposure to consumers. Our results show that perchlorate was detected in soil (median: 22.2 ng g^-1), drinking water (median: 3.0 ng mL^-1), fruits (median: 0.91 ng g^-1 fresh weight [FW]), lettuce (median: 5.0 ng g^-1 FW) and chard (median: 4.15 ng g^-1 FW). Interestingly, perchlorate concentrations detected in drinking water from three regions (Serena, Copiapo and Illapel) exceeded the USEPA interim drinking water health advisory level of 15 ng mL^-1. Median concentrations of perchlorate in non-nitrogenous fertilizers (3.1 mg kg^-1) were higher than those in nitrogenous fertilizers (1.3 mg kg^-1). Estimated daily intake (EDI) of perchlorate via drinking water was lower than the USEPA's reference dose (7000 ng kg^-1 bw day^-1). The EDI of perchlorate via vegetables (chard and lettuce) produced in northern Chile was three times higher than those produced in other regions. The results of this study provide information about perchlorate sources in Chile, which will be helpful in modifying current regulations.

Studies on perchlorate levels in powdered infant formulas available on the Polish market

Perchlorate has been acknowledged as a health threat due to its ability to interfere with iodine uptake by the thyroid gland. Infants and developing newborns have been considered as the most vulnerable groups to the perchlorate toxicity. A crucial source of perchlorate ingestion are powdered infant formulas. This study was designed to measure perchlorate content in thirty-one powdered infant formulas available on the Polish market. A rapid and sensitive ion chromatography method – conductivity cell detection – was applied to determine ClO 4 − {\rm{ClO}}_4^ - content. Limit of detection (0.150 µg/L) and limit of quantification (0.450 µg/L) were assessed. Collected samples were classified by the age of consumers: first stage, until the baby is six months old and follow-on formula for older children. Geometric mean of perchlorate concentration of 1.041 µg/L and 0.857 µg/L in the groups of the first stage and follow-on formulas were calculated, respectively. A health risk assessment revealed that the Tolerable Daily Intake (TDI) for perchlorate (0.3 µg/kg body weight/day) was exceeded only in a few milk samples. The findings suggest that perchlorate contamination of powdered infant formulas may not to be an immediate health issue, yet testing for ClO 4 − {\rm{ClO}}_4^ - should continuously be conducted. To the best of our knowledge, this is the first study concerning perchlorate content in infant formulas in Poland.

Perchlorate - properties, toxicity and human health effects: an updated review

Interest in perchlorate as environmental pollutant has increased since 1997, when high concentrations have been found in the waters of the Colorado River, USA. Perchlorate is very persistent in nature and it is slowly degraded. Although harmful effects of large doses of perchlorate on thyroid function have been proven, the environmental effects are still unclear. The primary objective of the present review is to collect prevailing data of perchlorate exposure and to discuss its impact on human health. The results show that more than 50% of reviewed works found significant associations of perchlorate exposure and human health. This review consists of the following sections: general information of perchlorate sources, its properties and determination methods, role and sources in human body including food and water intake, overview of the scientific literature on the research on the effect of perchlorate on human health from 2010 to 2020. Finally, conclusions and recommendations on future perchlorate studies concerning human exposure are presented.

Bioavailability Evaluation of Perchlorate in Different Foods In Vivo: Comparison with In Vitro Assays and Implications for Human Health Risk Assessment

Perchlorate in various foods continuously arouses public health concern. Bioavailability is a critical parameter to better estimate perchlorate exposure from diets. In this study, perchlorate bioavailability in five foods was determined in an in vivo mouse model and compared with in vitro bioaccessibility/bioavailability. The estimated in vivo perchlorate bioavailability for different foods ranged from 18.01 ± 4.53% to 45.60 ± 7.11%, with the order lettuce > pork > rice > milk powder > soybean. Moisture, fiber, and fat in foods were identified as critical factors affecting perchlorate bioavailability (correlation r = 0.71, 0.52, and -0.67, respectively). Linear regression analysis revealed that the in vitro perchlorate bioavailability determined using the Caco-2 cell model has the potential to estimate the in vivo perchlorate bioavailability in foods (R² = 0.67, slope = 1.33, and y intercept = 4.99). These findings provide insights into the effects of the food matrices on perchlorate bioavailability and could contribute to decrease the uncertainty regarding perchlorate dietary exposure risk assessment.

Apoptotic endocrinal toxic effects of perchlorate in human placental cells

BACKGROUND

Perchlorate is a strong oxidizing agent and has many adverse health effects. This study investigated the potential oxidative, apoptotic, and endocrinal toxic effects of perchlorate in human placenta-derived mesenchymal stem cells (HP-MSCs).

METHODS

HP-MSCs were treated with two doses of perchlorate (5 and 15 μg/L) for three days. The perchlorate's effects were detected by histopathological examination, aromatase/CYP19 A1 activity, reactive oxygen species production (ROS), and Caspase-3 expression.

RESULTS

The highest perchlorate concentration (15 μg/L) caused significant placental histopathological changes. The placental cell viability was significantly affected by a significant increase in ROS generation; caspase-3 expression, and a significant reduction of CYP 19 activity. Despite the slight induction effect of the lowest perchlorate concentration (5 μg/L) on caspase 3 expression, CYP 19 activity, and ROS generation, it did not affect placental cellular viability.

CONCLUSION

This study suggested that perchlorate could modulate aromatase activity and placental cytotoxicity. The continuous monitoring of the actual perchlorate exposure is needed and could be cost-effective.

Perchlorate Levels in Polish Water Samples of Various Origin

Perchlorate ion (ClO4−) is known as a potent endocrine disruptor and exposure to this compound can result in serious health issues. It has been found in drinking water, swimming pools, and surface water in many countries, however, its occurrence in the environment is still poorly understood. The information on perchlorate contamination of Polish waters is very limited. The primary objective of this study was to assess ClO4− content in bottled, tap, river, and swimming pool water samples from different regions of Poland and provide some data on the presence of perchlorate. We have examined samples of bottled, river, municipal, and swimming pool water using the IC–CD (ion chromatography–conductivity detection) method. Limit of detection and limit of quantification were 0.43 µg/L and 1.42 µg/L, respectively, and they were both above the current health advisory levels in drinking water. The concentration of perchlorate were found to be 3.12 µg/L in one river water sample and from 6.38 to 8.14 µg/L in swimming pool water samples. Importantly, the level of perchlorate was below the limit of detection (LOD) in all bottled water samples. The results have shown that the determined perchlorate contamination in Polish drinking waters seems to be small, nevertheless, further studies are required on surface and river samples. The inexpensive, fast, and sensitive IC–CD method used in this study allowed for a reliable determination of perchlorate in the analyzed samples. To the best of our knowledge, there are no other studies seeking to assess the perchlorate content in Polish waters.

An electrodialytic device for automated inorganic anion preconcentration with determination by ion chromatography-conductivity detection

A 4-layer sandwiched device (4LSD) well suited for coupling to online ion chromatography (IC) systems was described and simultaneously performed target anion enrichment, matrix removal and sample injection within seconds. The basic assembly consisted of an extraction solution channel, a sample solution channel and two electrolyte channels. Cation-exchange resin (CER) was utilized to support the solution chamber, increase electrical conductivity and improve pressure resistance to achieve compatibility with a peristaltic pump. Filter placement ensured loop circulation of the 4LSD and prevented resin leakage. The 4LSD showed comparable performance to that of conventional solid-phase extraction (SPE) pretreatment in terms of matrix interference removal while enabling automation. The applied current, sample/extraction solution flow rate ratio, and initial concentration were discussed and optimized. Controllable 1-40-fold enrichment can be ensured. The migration phenomenon of different anions was discussed. F^-, Cl^-, NO₂^-, Br^-, NO₃^-, SO₄^2- and ClO₄^- exhibited satisfactory linear detection ranges within 2.5-1000 μg·L^-1, and the calculated limits of detection (LODs) in milk formula were within the 0.097-0.79 mg·kg^-1 range. The 4LSD was successfully applied to the determination of anions in milk formula with good spiked recoveries ranging between 92.54% and 107.2%, except for the NO₂^- recovery. The relative standard deviations (RSDs) ranged from 0.69% to 8.29%.

Dietary exposure assessment to perchlorate in the Taiwanese population: A risk assessment based on the probabilistic approach

Perchlorate is an endocrine-disrupting chemical (EDC) that contaminate various foodstuffs. Exposure to perchlorate may cause severe health problems, mainly thyroid dysfunction. However, information on perchlorate contamination of consumer foods in Taiwan is limited. This study investigated perchlorate levels in 310 food samples belonging to 12 food groups collected from Taiwanese markets. A probabilistic risk assessment was conducted to assess the related exposure to Taiwanese people. Perchlorate was detected in 65% of the samples and high levels were identified in certain plant-origin, fruit, and processed food samples. A probabilistic approach was used to estimate daily dietary dose (Monte Carlo-estimated 95th percentile dietary exposure [MCS 95]) by using the Taiwan National Food Consumption database for 14 sex/age groups. The highest and lowest average daily doses (ADDs) were in the age groups of >65 years (MCS 95 = 3.60/3.90 [male/female] μg/kg bw/day) and 16-18 years (MCS 95 = 1.70/1.47 [M/F] μg/kg bw/day), respectively. The 95th percentile of the hazard index of exposure to perchlorate of all sex/age groups far exceeded the tolerable daily intake (0.3 μg/kg bw/day) and reference dose (0.7 μg/kg bw/day) set by the European Food Safety Authority and US EPA, respectively, but it was lower than the provisional maximum tolerable daily intake (10 μg/kg bw/day) suggested by the Joint FAO/WHO Expert Committee on Food Additives. The intake quantity and concentrations of perchlorate from vegetables, fruits, and whole grains are the critical contributors for the ADDs and integrated risk of dietary exposure to perchlorate. Long-term exposure through diets should be considered, instead of focusing on individual EDC during dietary risk assessment in specific populations. Furthermore, cumulative risks for exposure to multiple contaminants, particularly those causing thyroid adverse effects, may be higher than that from perchlorate exposure alone.

Monitoring of polar pesticides and contaminants in edible oils and nuts by liquid chromatography-tandem mass spectrometry

A single method was developed for the determination of polar pesticides (fosetyl-Al and its metabolite, phosphonic acid, and ethephon) and environmental contaminants (chlorate and perchlorate) in edible oils and nuts. Two extraction methods based on QuPPe-PO approach (Quick Polar Pesticides Method for products of Plant Origin) were optimized. In oils, a single extraction using water acidified with formic acid (1%) was performed, while in nuts, the clean-up step was modified. C18 was used as sorbent and an extra cleaning step with n-hexane was added. The extracts were analysed by liquid chromatography coupled to a triple quadrupole mass analyser (LC-QqQ-MS/MS). The method was validated and the limit of quantification was 0.01 mg kg^-1 for all analyte-matrix combination. Recoveries from 70 to 120%, and intra and inter-day precision values ≤20% were obtained. Forty samples of edible oils and nuts were analysed, detecting phosphonic acid in nuts at concentrations up to 4.6 mg kg^-1.

Accurate, sensitive and rapid determination of perchlorate in tea by hydrophilic interaction chromatography-tandem mass spectrometry

Perchlorate is an environmental contaminant interrupting thyroid hormone production, and perchlorate in tea has raised wide concern recently. In this study, an accurate method was developed for the determination of perchlorate in tea using hydrophilic interaction chromatography-tandem mass spectrometry and a simplified QuEChERS procedure. The method utilized a zwitterion HILIC column for separation, and the optimal gradient eluents consisted of acetonitrile and aqueous solution with 0.1% formic acid and 20 mmol L^-1 ammonium formate. Calibration curves were fitted by the quadratic model with 1/x weight instead of the linear model. As perchlorate was only partially extractable when using acetonitrile or methanol as the extraction solvent, acetonitrile/water (1 : 1, v/v) was chosen to extract perchlorate from tea samples. Graphitized carbon black was used as the dispersive solid phase extraction sorbent to clean up tea extracts. The method exhibited satisfactory accuracy with recoveries of 81.4-100.9% and relative standard deviations of 1.3-14.5% for green and black teas. The limit of quantitation was 0.005 mg kg^-1, while the limits of detection were 0.0011 mg kg^-1 for green tea and 0.0013 mg kg^-1 for black tea, indicating an excellent sensitivity of this method. A 100% positive rate of perchlorate was found in 100 real tea samples, and the concentrations ranged from 0.0030 mg kg^-1 to 0.78 mg kg^-1. This accurate, sensitive and rapid method would be suitable for monitoring, risk assessment and source identification of perchlorate in tea.

Interference on Iodine Uptake and Human Thyroid Function by Perchlorate-Contaminated Water and Food

Background: Perchlorate-induced natrium-iodide symporter (NIS) interference is a well-recognized thyroid disrupting mechanism. It is unclear, however, whether a chronic low-dose exposure to perchlorate delivered by food and drinks may cause thyroid dysfunction in the long term. Thus, the aim of this review was to overview and summarize literature results in order to clarify this issue. Methods: Authors searched PubMed/MEDLINE, Scopus, Web of Science, institutional websites and Google until April 2020 for relevant information about the fundamental mechanism of the thyroid NIS interference induced by orally consumed perchlorate compounds and its clinical consequences. Results: Food and drinking water should be considered relevant sources of perchlorate. Despite some controversies, cross-sectional studies demonstrated that perchlorate exposure affects thyroid hormone synthesis in infants, adolescents and adults, particularly in the case of underlying thyroid diseases and iodine insufficiency. An exaggerated exposure to perchlorate during pregnancy leads to a worse neurocognitive and behavioral development outcome in infants, regardless of maternal thyroid hormone levels. Discussion and conclusion: The effects of a chronic low-dose perchlorate exposure on thyroid homeostasis remain still unclear, leading to concerns especially for highly sensitive patients. Specific studies are needed to clarify this issue, aiming to better define strategies of detection and prevention.

Occurrence of perchlorate, chlorate and polar herbicides in different baby food commodities

The incidence of endocrine disruptors, both possible (glyphosate and glufosinate), and demonstrated (perchlorate and chlorate), was estimated in baby food commodities (meat, fish, cheese, vegetable and fruit). Ion-chromatography coupled to high resolution mass spectrometry analysis of the 105 samples did not show traces of glyphosate, glufosinate or their metabolites, while in 10.5% of the samples a quantifiable amount of perchlorate was found. Some samples based on fruit and vegetables revealed a substantial amount of chlorate, especially the preparations that contained carrots and potatoes: five samples were in a concentration range of 40-120 μg kg^-1, while one homogenized pear sample reached 372.2 μg kg^-1. The pure meat samples revealed occasional chlorate appearance, with less than 10 μg kg^-1. This is the first report of chlorate evaluated in various types of baby food and may serve as symptomatic data regarding its occurrence in infant/toddler diets. Therefore, effective monitoring programs and subsequent strict regulations are strongly required.

Safety assessment of the substance (triethanolamine-perchlorate, sodium salt) dimer, for use in food contact materials

The EFSA Panel on Food Contact Materials, Enzymes and Processing Aids (CEP) assessed the safety of the substance (triethanolamine-perchlorate, sodium salt) dimer, FCM substance No 1080, intended to be used as a thermal stabiliser at up to 0.15% w/w in rigid poly(vinyl chloride) (PVC) for repeated use bottles in contact with water. No thermal degradation of the substance is expected during the manufacture of the PVC articles. In water, the substance fully dissociates into triethanolamine, sodium (cations) and perchlorate. Therefore, migration would lead to exposure to triethanolamine and perchlorate and not to the substance itself. Specific migration of perchlorate, ethanolamine, diethanolamine and triethanolamine was tested under repeated use conditions covering the requested uses. After the second and third contacts, perchlorate was detected at ca. 0.3 μg/kg food. Ethanolamine, diethanolamine and triethanolamine were not detected in any of the three contacts at an estimated limit of detection of 0.03 mg/kg food. The available in vitro studies on the substance confirmed the lack of concern for genotoxicity, as anticipated by the dissociation of the substance into authorised non-genotoxic substances. Therefore, the CEP Panel concluded that the substance is not of safety concern for the consumer if used, under the condition requested by the applicant, as an additive at up to 0.15% w/w in rigid PVC for repeated use bottles intended for contact with water. Additionally, the migration of triethanolamine and perchlorate should not exceed the specific migration limits (SMLs) of 50 μg/kg food and 2 μg/kg food, respectively, set in the Regulation (EU) 10/2011. This evaluation also covers acidic foods such as fruit juices that can reasonably be foreseen to be in contact.

Short communication: Effects of electrochemically activated drinking water on bovine milk production and composition, including chlorate, perchlorate, and fatty acid profile

The objective of this study was to assess the effects of electrochemically activated drinking water (ECW) on milk chlorate, milk perchlorate, milk iodine, milk composition, milk fatty acid profile, and overall performance of dairy cows. Ten Red Danish cows in mid-lactation (203 ± 31 d in milk; average ± SD) were chosen from these 2 groups for intensive sampling. The treated group drank water with 4 ppm of ECW (29 mg/L of chlorate of Neuthox, Danish Clean Water A/S, Sønderborg, Denmark). The treatment lasted 60 consecutive days, with milk and water sampling on d 0, 30, and 60. Additionally, milk samples from both the control group and treated group were taken on d 90 to assess if any carry-over effect was present. Interactions between period and milk yield and somatic cell for the full group and period and milk fat content and milk urea nitrogen in the selected animals occurred. Milk yield was not significantly affected by treatments. Milk fat, milk fatty acid profile, chlorate, perchlorate, and iodine contents were not significantly different between treatments. Milk urea increased, whereas β-hydroxybutyrate and somatic cell count decreased significantly in the treated groups. Results showed that at a dosing of 4 ppm of ECW, both chlorate and perchlorate concentrations in milk (<0.002 mg/kg) were low, and no deleterious effects on milk production or milk chemical composition were observed. These data can be of use when assessing the effects of ECW on milk and milk powder chlorate and perchlorate levels and provide a context for assessing the potential for influencing human health under the conditions prevailing on a commercial dairy farm.

LC-ESI-MS/MS determination of oxyhalides (chlorate, perchlorate and bromate) in food and water samples, and chlorate on household water treatment devices along with perchlorate in plants

The results of the validation study of the LC-ESI-MS/MS method for the determination of chlorate (ClO₃^-), perchlorate (ClO₄^-) and bromate (BrO₃^-) in water and food samples are summarized. Towards this, 284 samples of drinking water were analysed, out of which the 69% contained chlorate above the limit of quantitation (LOQ) of 0.01 mg/L, with maximum amount of 1.1 mg/L. Only 6 samples were found to be positive with perchlorate at levels <0.01 mg/L. Bromate was detected in 5 drinking water samples at levels above the LOQ, at concentrations up to 0.026 mg/L. For the validation of the method in food, 108 blank samples were spiked with chlorate and perchlorate for the LC-MS/MS analysis at two levels. In total 247 food samples from the market of 19 different commodities including fruits, vegetables, cereals and wine, were analysed. The maximum concentration of chlorate was found at 0.83 mg/kg in a sample of cultivated mushrooms. The number of samples contaminated with perchlorate was also small, with all the determined concentrations below the LOQ of 0.05 mg/kg. Experiments for the chlorate reduction in drinking water, showed that reverse osmosis treatment is effective in particular with newly installed cartridges. Finally, according to the results of the pilot study when chlorinated water is used for the plant irrigation, accumulation of chlorate is observed, especially in the green parts of the plant. Perchlorate was also detected in leafy samples, although it was not present in the irrigation water.

Dietary Exposure Assessment of Potentially Toxic Trace Elements in Fruits and Vegetables Sold in Town of Kapan, Armenia

Fruits and vegetables grown under the impact of Armenia's mining industry are widely sold in markets of adjacent towns. As the share of fruits and vegetables in Armenians' diet is significant, the present study aims to assess the dietary exposure of potentially toxic trace elements through the intake of fruits and vegetables sold in Kapan town, located in the biggest mining region of Armenia. The concentrations of Cu, Mo, Ni, Cr, Pb, Zn, Hg, As, and Cd in 15 types of fruits and vegetables were determined. Non-carcinogenic and carcinogenic risks were assessed. Although the estimated daily intakes of trace elements for each studied food item did not exceed health-based guidelines values, in case of the combined consumption of fruits and vegetables estimated cumulative daily intakes exceeded reference doses for Cu and Mo. Moreover, carcinogenic risk for the majority of fruits and vegetables exceeded the EPA recommended risk level of 10^-6, indicating adverse health effect to local population. The outcomes of this study can serve as a basis for further research that will consider many other exposure pathways (i.e., inhalation or dermal pathways) in order to ensure the safety of the residents living under the impact of mining industry.

Worldwide occurrence and origin of perchlorate ion in waters: A review

Perchlorate (ClO₄^-) is a persistent water soluble oxyanion of growing environmental interest. Perchlorate contamination can be a health concern due to its ability to disrupt the use of iodine by the thyroid gland and the production of metabolic hormones. Its widespread presence in surface water and groundwater makes the aquatic environment a potential source of perchlorate exposure. However, the amount of published data on perchlorate origins and water contamination worldwide remains spatially limited. Here, we present an overview of research on perchlorate origins and occurrences in water, and the methodology to distinguish the different perchlorate sources based on isotope analysis. All published ranges of isotopic content in perchlorate from different sources are presented, including naturally occurring and man-made perchlorate source types, as well as the effects of isotope fractionation that accompanies biodegradation processes. An example of a case study in France is presented to emphasize the need for further research on this topic.

An Improved, Rapid, and Sensitive Ultra-High-Performance Liquid Chromatography-High-Resolution Orbitrap Mass Spectrometry Analysis for the Determination of Highly Polar Pesticides and Contaminants in Processed Fruits and Vegetables

A rapid, specific, and sensitive method based on quick polar pesticide extraction and ultra-high-performance liquid chromatography coupled to high-resolution mass spectrometry with an Orbitrap analyzer was evaluated. Usually, pesticides were analyzed individually using derivatization or ion-pairing techniques and detection by ion chromatography. We identified and simultaneously quantified 6 highly polar compounds (glyphosate, aminomethyl phosphonic acid (AMPA), phosphonic acid, fosetyl-Al, chlorate, and perchlorate) in 83 processed fruits and vegetables as well as 15 infant foods. Isotopically labeled internal standards ¹⁸O₄-perchlorate, ¹⁸O₃-chlorate, and ¹³C₂¹⁵N-glyphosate were applied to quantify five polar compounds and to compensate for any factor affecting the recovery rates. Only AMPA was quantified using a standard addition approach to compensate for matrix effects. This analytical methodology is fast and reliable, and it is also able to satisfy the strict requirements of infant food analysis.

Perchlorate contamination in Chile: Legacy, challenges, and potential solutions

This paper reviews the unique situation of perchlorate contamination in Chile, including its sources, presence in environmental media and in the human population, and possible steps to mitigate its health impacts. Perchlorate is a ubiquitous water contaminant that inhibits thyroid function. Standards for drinking water range from 2 to 18 µg L^-1 in United States and Europe. A major natural source of perchlorate contamination is Chile saltpeter, found in the Atacama Desert. High concentrations of perchlorate have presumably existed in this region, in soils, sediments, surface waters and groundwaters, for millions of years. As a result of this presence, and the use of Chile saltpeter as a nitrogen fertilizer, perchlorate in Chile has been found at concentrations as high as 1480 µg L^-1 in drinking water, 140 µg/kg^-1 in fruits, and 30 µg L^-1 in wine. Health studies in Chile have shown concentrations of 100 µg L^-1 in breast milk and 20 µg L^-1 in neonatal serum. It is important to acknowledge perchlorate as a potential health concern in Chile, and assess mitigation strategies. A more thorough survey of perchlorate in Chilean soils, sediments, surface waters, groundwaters, and food products can help better assess the risks and potentially develop standards. Also, perchlorate treatment technologies should be more closely assessed for relevance to Chile. The Atacama Desert is a unique biogeochemical environment, with millions of years of perchlorate exposure, which can be mined for novel perchlorate-reducing microorganisms, potentially leading to new biological treatment processes for perchlorate-containing waters, brines, and fertilizers.

Benchmark dose (BMD) modeling: current practice, issues, and challenges

Benchmark dose (BMD) modeling is now the state of the science for determining the point of departure for risk assessment. Key advantages include the fact that the modeling takes account of all of the data for a particular effect from a particular experiment, increased consistency, and better accounting for statistical uncertainties. Despite these strong advantages, disagreements remain as to several specific aspects of the modeling, including differences in the recommendations of the US Environmental Protection Agency (US EPA) and the European Food Safety Authority (EFSA). Differences exist in the choice of the benchmark response (BMR) for continuous data, the use of unrestricted models, and the mathematical models used; these can lead to differences in the final BMDL. It is important to take confidence in the model into account in choosing the BMDL, rather than simply choosing the lowest value. The field is moving in the direction of model averaging, which will avoid many of the challenges of choosing a single best model when the underlying biology does not suggest one, but additional research would be useful into methods of incorporating biological considerations into the weights used in the averaging. Additional research is also needed regarding the interplay between the BMR and the UF to ensure appropriate use for studies supporting a lower BMR than default values, such as for epidemiology data. Addressing these issues will aid in harmonizing methods and moving the field of risk assessment forward.

Endocrine Disrupters and the Safety of Food Chains

Endocrine disrupters (ED) are a heterogeneous group of chemicals including persistent contaminants, pesticides, as well as compounds present in consumer products and natural substances. For most ED, the food chain is a current major exposure route for the general population. ED can enter the food chain through the living environment (e.g., feeds, fertilizers) of food-producing organisms, be directly employed in food production (e.g., pesticides) or be released from food contact materials (such as bisphenol A or phthalates); in addition, the endocrine disruption potential of some natural compounds in edible plants, including the so-called phytoestrogens, should not be overlooked. An exposure assessment has to consider the specific liability of food commodities to contamination with specific ED (e.g., polychlorinated and polybrominated chemicals in lipid-rich foods). The paper discusses the main toxicological research issues in order to support the risk assessment of ED in food chains, including: the potential for additive, 'cocktail' effects (as from multiple pesticide residues); the long-term effects on target body systems (e.g., reproductive, nervous) elicited by exposure during prenatal as well as postnatal life stage windows, and toxicant/nutrient interactions (e.g., thyroid-targeting ED and iodine status). Food safety systems should exploit the available knowledge to improve prevention of long-term risks along the whole food chain.

Dietary exposure assessment to perchlorate in the European population

EFSA performed a human exposure assessment for perchlorate taking into account occurrence data in the EFSA database from samples taken after 1 September 2013. A data set of 18,217 analytical results provided by governmental organisations of 16 European countries was available. Some data were also provided by food business operators. Several food groups were represented in the data set. Relatively high mean middle bound occurrence values were found in dried products, like 'Tea and herbs for infusion' (324 μg/kg) and 'Herbs, spices and condiments' (63 μg/kg), and in some fresh vegetables, like 'Radishes' (117 μg/kg), 'Rocket salad, rucola' (75 μg/kg) and 'Spinach (fresh)' (132 μg/kg). The mean and P95 of exposure to perchlorate across dietary surveys were estimated using chronic and short-term scenarios across different population groups. In the chronic scenario, infants, toddlers and other children showed exposure in the range (minimum lower bound (LB)-maximum upper bound (UB)) 0.04-0.61 μg/kg body weight (bw) per day, while in the older population groups, the range was 0.04-0.19 μg/kg bw per day; similarly, in the young population groups, the P95 of chronic exposure range was 0.09-1.0 μg/kg bw per day, while in the older population groups, it was 0.07-0.34 μg/kg bw per day. 'Vegetable and vegetable products', 'Milk and dairy products' and 'Fruit and fruit products' were found to be important contributors to the exposure across all population groups. Other food groups were relevant for specific population groups. The mean short-term exposure of infants, toddlers and other children was in the range of 0.40-2.3 μg/kg bw per day, while in the older population groups, the range was 0.26-1.3 μg/kg bw per day; similarly, in the young population groups, the P95 short-term exposure range was 0.94-6.5 μg/kg bw per day, while in the older population groups, the range was 0.67-3.6 μg/kg bw per day.

Development and Validation of Ion Chromatography-Tandem Mass Spectrometry-Based Method for the Multiresidue Determination of Polar Ionic Pesticides in Food

An extraction method using acidified methanol based on the quick polar pesticide (QuPPe) method using suppressed ion chromatography coupled to mass spectrometry was developed and validated for the direct analysis of polar pesticides, without the need for derivatization or ion pairing, in cereals and grapes. The method was robust, and results for glyphosate, aminomethyl phosphonic acid (AMPA), N-acetyl-AMPA, glufosinate, 3-methylphosphinicopropionic acid (3-MPPA), N-acetyl glufosinate, ethephon, chlorate, perchlorate, fosetyl aluminum, and phosphonic acid at three concentration levels (typically 0.01, 0.05, and 0.1 mg/kg) were compliant with SANTE/11945/2015 guideline method performance criteria. Cereal-based infant food proved to be a more challenging matrix and validated only for glyphosate, chlorate, and perchlorate at 0.005, 0.01, and 0.05 mg/kg. The developed method enables the multiresidue analysis of 12 ionic pesticides and relevant metabolites in a single analysis. Until now, the analysis of these compounds required several different single-residue methods using different chromatographic conditions. This multiresidue approach offers the possibility of more cost-effective and more efficient monitoring of polar ionic pesticides and contaminants that are of concern to food regulation bodies and consumers.

Fast determination of four polar contaminants in soy nutraceutical products by liquid chromatography coupled to tandem mass spectrometry

An analytical method based on a modified QuPPe (quick polar pesticide) extraction procedure coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS) was evaluated for the determination of four polar compounds (chlorate, fosetyl-Al, maleic hydrazide, and perchlorate) in nutraceutical products obtained from soy. Experimental conditions including extraction such as solvent, acidification, time, and clean-up sorbents were varied. Acidified acetonitrile (1 % formic acid, v/v) was used as extraction solvent instead of methanol (conventional QuPPe), which provides a doughy mixture which cannot be injected into the LC. Clean-up or derivatization steps were avoided. For analysis, several stationary phases were evaluated and Hypercarb (porous graphitic carbon) provided the best results. The optimized method was validated and recoveries ranged between 46 and 119 %, and correction factors can be used for quantification purposes bearing in mind that inter-day precision was equal to or lower than 17 %. Limits of quantification (LOQs) ranged from 4 to 100 μg kg-1. Soy-based nutraceutical products were analyzed and chlorate was detected in five samples at concentrations between 63 and 1642 μg kg-1. Graphical Abstract Analysis of polar compounds in soy-based nutraceutical products.

ENDOCRINOLOGY IN PREGNANCY: Pregnancy and the incidence, diagnosing and therapy of Graves' disease

Thyroid hormones are essential developmental factors, and Graves' disease (GD) may severely complicate a pregnancy. This review describes how pregnancy changes the risk of developing GD, how early pregnancy by several mechanisms leads to considerable changes in the results of the thyroid function tests used to diagnose hyperthyroidism, and how these changes may complicate the diagnosing of GD. Standard therapy of GD in pregnancy is anti-thyroid drugs. However, new studies have shown considerable risk of birth defects if these drugs are used in specific weeks of early pregnancy, and this should be taken into consideration when planning therapy and control of women who may in the future become pregnant. Early pregnancy is a period of major focus in GD, where pregnancy should be diagnosed as soon as possible, and where important and instant change in therapy may be warranted. Such change may be an immediate stop of anti-thyroid drug therapy in patients with a low risk of rapid relapse of hyperthyroidism, or it may be an immediate shift from methimazole/carbimazole (with risk of severe birth defects) to propylthiouracil (with less risk), or maybe to other types of therapy where no risk of birth defects have been observed. In the second half of pregnancy, an important concern is that not only the mother with GD but also her foetus should have normal thyroid function.

Assessing the potential impact on the thyroid axis of environmentally relevant food constituents/contaminants in humans

Occurrence and mode of action of potentially relevant goitrogens in human nutrition and their mode of action (MOA) are reviewed, with special focus on the anionic iodine uptake inhibitors perchlorate (PER), thiocyanate (SCN) and nitrate (NO3). Epidemiological studies suggest persistent halogenated organic contaminants and phthalates as well as certain antimicrobials to deserve increased attention. This also applies to natural goitrogens, including polyphenols and glucosinolates, food constituents with limited data density concerning human exposure. Glucosinolates present in animal feed are presumed to contribute to SCN transfer into milk and milk products. PER, SCN and NO3 are well-investigated environmental goitrogens in terms of MOA and relative potency. There is compelling evidence from biomarker monitoring that the exposure to the goitrogens SCN and NO3 via human nutrition exceeds that of PER by orders of magnitude. The day-to-day variation in dietary intake of these substances (and of iodide) is concluded to entail corresponding variations in thyroidal iodide uptake, not considered as adverse to health or toxicologically relevant. Such normal variability of nutritional goitrogen uptake provides an obvious explanation for the variability in radioactive iodine uptake (RAIU) measurements observed in healthy individuals. Based on available data, a 20 % change in the thyroidal uptake of iodide is derived as threshold value for a biologically meaningful change induced by perchlorate and other goitrogens with the same MOA. We propose this value to be used as the critical effect size or benchmark response in benchmark dose analysis of human RAIU data. The resulting BMDL20 is 0.0165 mg/kg bw/day or 16.5 μg/kg bw/day. Applying a factor of 4, to allow for inter-human differences in toxicokinetics, leads to a TDI for perchlorate of 4 μg/kg bw/day.