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1.
A major pathway for exposure to many pesticides is through diet. The objectives were to rank pesticides by comparing their calculated daily dietary exposure as determined by EPA's Stochastic Human Exposure and Dose Simulation (SHEDS) to single pesticides for different age groups to acceptable daily intakes (ADI), characterize pesticide trends in exposures over different time periods, and determine commodities contributing to pesticide exposures. SHEDS was applied, using Pesticide Data Program (PDP) (1991–2011) and pesticide usage data on crops from USDA combined with NHANES dietary consumption data, to generate exposure estimates by age group. ADI data collected from EPA, WHO, and other sources were used to rank pesticides based on relativeness of the dietary exposure potential to ADI by age groups. Sensitivity analysis provided trends in pesticide exposures. Within SHEDS, commodities contributing the majority of pesticides with greatest exposure potential were determined. The results indicated that the highest ranking pesticides were methamidophos and diazinon which exceeded 100% of the ADI. Sensitivity analysis indicated that exposure to methamidophos, diazinon, malathion, ethion and formetanate hydrochloride had a marked decrease from 1991–1999 to 2000–2011. Contributions analysis indicated that apples, mushroom, carrots, and lettuce contributed to diazinon exposure. Beans and pepper contributed to methamidophos exposure.  相似文献   

2.
Glyphosate is a herbicide used to control broad-leaved weeds. Some uses of glyphosate in crop production can lead to residues of the active substance and related metabolites in food. This paper uses data on residue levels, processing information and consumption patterns, to assess theoretical lifetime dietary exposure to glyphosate.Initial estimates were made assuming exposure to the highest permitted residue levels in foods. These intakes were then refined using median residue levels from trials, processing information, and monitoring data to achieve a more realistic estimate of exposure. Estimates were made using deterministic and probabilistic methods. Exposures were compared to the acceptable daily intake (ADI)—the amount of a substance that can be consumed daily without an appreciable health risk.Refined deterministic intakes for all consumers were at or below 2.1% of the ADI. Variations were due to cultural differences in consumption patterns and the level of aggregation of the dietary information in calculation models, which allows refinements for processing. Probabilistic exposure estimates ranged from 0.03% to 0.90% of the ADI, depending on whether optimistic or pessimistic assumptions were made in the calculations. Additional refinements would be possible if further data on processing and from residues monitoring programmes were available.  相似文献   

3.
Cypermethrin (CY) is a frequently used class II pyrethroid pesticide, while piperonyl butoxide (PBO) plays a major role in the pesticide formulation of synthetic pyrethroids. Synthetic pyrethroids are metabolized in mammals via oxidation and ester hydrolysis. PBO can prevent the metabolism of CY and enhances its pesticide effect. While this potentiation effect reduces the amount of pesticide required to eliminate insects, it is not clear how this mixture affects mammals. In our in vivo experiment, New Zealand white male rabbits were exposed to low and high doses of CY, PBO, and their combinations, for 4 months. Genotoxicity and cytotoxicity were monitored by measuring binucleated cells with micronuclei (BNMN), micronuclei (MN) and the cytokinesis block proliferation index (CBPI) in lymphocytes. After two months of exposure, a statistically significant increase in the frequency of BNMN was observed for all exposed animals (p < 0.001) in a dose-dependent way. MN were significantly elevated compared to controls (p < 0.001), with high dose groups reaching a 442% increase when co-exposed. BNMN and MN continued to increase after four months. Histopathological examination of lesions showed damage involving inflammation, attaining lymphoplasmatocytic infiltration in the high dose groups. Both CY and PBO cause liver and kidney inflammation and induce genotoxicity.  相似文献   

4.
PurposeExtensive acute and subacute toxicities studies are required to evaluate the toxicological profile of the novel cardiac perfusion imaging tracer 123I-CMICE-013 to support applications for clinical trials.MethodsSprague-Dawley rats and Gottingen minipigs received injections of non-radioactive 127I-CMICE-013 at two dosage levels of 1 and 5 μg/kg, and vehicle buffer as control. In the acute toxicity studies, each animal was injected on two occasions 24 h apart and then underwent a 14-day recovery period; in the subacute study, animals received daily injections for 14 days continuously. The health status and mortality of test animals were monitored daily and body weight, food consumption, physiological and biochemical parameters were measured at various time points during the study. Animals were euthanized at the end of the studies and dissected for pathologic examination of organs and tissues.ResultsThe acute and subacute administrations of injections of the non-radioactive CMICE-013 in rats and minipigs were well tolerated. Little to no dosing-related adverse effects were observed in animal body and organ weights, hematology, coagulation, clinical chemistry, urinalysis, ophthalmoscopy, electrocardiograms, heart rates, blood pressure, macroscopic and microscopic examination of the preserved animal tissues including the brain.ConclusionThe lack of adverse effects from acute and subacute dosing suggest that the CMICE-013 injection solution has a reasonable safety margin within the designed concentration range to be utilized in imaging applications. The dosage level of 5 μg/kg was considered the no adverse effect level for both rats and minipigs based on our acute and subacute studies.  相似文献   

5.
We summarized the findings of toxicity studies on graphene-based nanomaterials (GNMs) in laboratory mammals. The inhalation of graphene (GP) and graphene oxide (GO) induced only minimal pulmonary toxicity. Bolus airway exposure to GP and GO caused acute and subacute pulmonary inflammation. Large-sized GO (L-GO) was more toxic than small-sized GO (S-GO). Intratracheally administered GP passed through the air-blood barrier into the blood and intravenous GO distributed mainly in the lungs, liver, and spleen. S-GO and L-GO mainly accumulated in the liver and lungs, respectively. Limited information showed the potential behavioral, reproductive, and developmental toxicity and genotoxicity of GNMs. There are indications that oxidative stress and inflammation may be involved in the toxicity of GNMs. The surface reactivity, size, and dispersion status of GNMs play an important role in the induction of toxicity and biodistribution of GNMs. Although this review paper provides initial information on the potential toxicity of GNMs, data are still very limited, especially when taking into account the many different types of GNMs and their potential modifications. To fill the data gap, further studies should be performed using laboratory mammals exposed using the route and dose anticipated for human exposure scenarios.  相似文献   

6.
Tembotrione is a triketone herbicide, usually used for post-emergence weed control in corn. Currently, there is little or no published data on its genotoxicity to human cells either in vitro or in vivo. This study evaluated the impact of acute (4 and 24 h) exposure to low concentrations of tembotrione [corresponding to the acceptable daily intake (0.17 μg/mL), residential exposure level (0.002 μg/mL) and acceptable operator exposure level (0.0012 μg/mL)] on human hepatocellular carcinoma cell line HepG2, using biomarkers of oxidative stress, CCK-8 colorimetric assay for cell viability, alkaline comet assay, and cytokinesis-block micronucleus “cytome” assay. Tembotrione applied at concentrations likely to be encountered in occupational and residential exposures induced cytogenetic outcomes in non-target cells despite non-significant changes in the values of oxidative stress biomarkers. We assume that the observed effects were mainly the consequence of impaired metabolic pathways in HepG2 cells due to the inhibition of the enzyme 4-hydroxyphenyl-pyruvate-dioxygenase by tembotrione, which possibly caused a depletion of folate levels leading to excess formation of nuclear buds in the affected cells. Regardless of the fact that tembotrione was previously reported negative for mutations and chromosome aberrations in vitro, our findings call for more precaution in its use.  相似文献   

7.
Mycotoxin producing moulds may contaminate numerous agricultural commodities either before harvest or during storage. A varied diet consisting of different foods may therefore be contaminated with a range of mycotoxins. The aim of the present study was to study concurrent exposure to mycotoxins through urinary multi-biomarker analysis, as well as its possible associations with the diet.Urinary samples from 252 adults, participating in the Swedish national dietary survey Riksmaten 2010–11, were collected together with a 4-day diet record. Concurrent mycotoxin exposure was studied using a multi-biomarker LC-MS/MS method. The results revealed that exposure to mycotoxins is common and concurrent exposure to more than one toxin was found in 69% of the study population. However, when comparing the number of toxins detected with the reported consumption data it was difficult to distinguish food patterns which would indicate an increased risk of exposure to many mycotoxins simultaneously.This is the first study to investigate concurrent mycotoxin exposure and urinary levels of fumonisin B1 (FB1), fumonisin B2 (FB2), nivalenol (NIV), ochratoxin A (OTA), zearalenone (ZEA), α-zearalenol (α-ZOL), β-zearalenol (β-ZOL) and de-epoxydeoxynivalenol (DOM-1) among adults in Sweden.  相似文献   

8.
Octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (CAS Reg. No. 2082-79-3), currently marketed as Irganox 1076 (I-76), is a sterically hindered phenolic antioxidant used in a variety of organic substrates, including those used in the manufacture of food contact articles. In 2012, the US Food and Drug Administration (USFDA), Office of Food Additive Safety (OFAS), initiated a post-market re-evaluation of the food contact applications of I-76. This project aimed to ensure that current dietary exposures from the use of I-76 in food contact articles are accurately captured and the safety assessment considered all relevant and available toxicological information. To accomplish these aims, the USFDA reviewed the available toxicological studies and chemistry information on food contact applications of I-76. Based on this in-depth analysis, a NOAEL of 64 mg/kg-bw/d (female rats) from a chronic rat study and a cumulative estimated dietary intake (CEDI) of 4.5 mg/p/d, was used to calculate a margin of exposure (MOE) of ∼850. We concluded that the previous and current exposure levels provide an adequate margin of safety (MOS) and remain protective of human health for the regulated uses.  相似文献   

9.
The gavage route is often used for the toxicological evaluation of food contaminants. This route does not take into account absorption of the toxicants through the buccal mucosa, as evidenced in dogs for bisphenol A (BPA). Our goal was to determine the functional significance of buccal BPA absorption during dietary exposure. Four ewes received BPA by nasogastric gavage (100 mg/kg) and through food pellets (10 mg/kg), 13 days apart. The time course of serum concentrations of BPA and its main metabolite BPA-G was submitted to non-compartmental analysis. The dietary route led to 3-fold higher bioavailability as compared to gavage. The ratio of BPA-G to BPA concentrations varied greatly over time after the food administration, but not after gavage, suggesting a delayed metabolism of BPA after dietary exposure. The maximum entrance rate of BPA in the systemic circulation, determined by deconvolution analysis, was much higher after dietary administration than after gavage and a biphasic pattern of BPA entry was observed in 3 of the 4 ewes. Our results evidenced a dual mechanism of BPA absorption (buccal and digestive) after dietary exposure and highlight the necessity to take buccal absorption into account when evaluating food contaminants.  相似文献   

10.
Seabuckthorn (Hippophae rhamnoides L.) has been traditionally used as medicine and nutritional supplement for a long period of time. However, information on the systemic toxicity and safety evaluation of seabuckthorn and its extracts is still scarce. The purpose of this study was to evaluate the potential toxicity of seabuckthorn oil by an acute oral toxicity study in mice and a 90-day repeated oral toxicity study in rats. No mortality or signs of toxicity was observed in mice treated with 20 mL/kg body weight seabuckthorn oil in the acute toxicity study. In the subchronic toxicity study, 80 Sprague-Dawley rats (10 animals per sex per treatment group) were administrated with 10, 5, 2.5 and 0 (control) mL/kg body weight of seabuckthorn oil daily for 90 days by gavage. There were no signs of toxicity and treatment-related changes in rats treated with seabuckthorn oil on mortality, body and organ weights, food consumption, blood biochemistry and hematology, gross necropsy and histopathological examinations. Based on the finding of this study, the maximum tolerated dose of seabuckthorn oil was >20 mL/kg for mice for acute toxicity study, and the no-observed-adverse-effect level was 10 mL/kg body weight for both male and female rats for 90-day toxicity study.  相似文献   

11.
Timosaponin BII (TBII), a major steroidal saponin isolated from Anemarrhena asphodeloides Bge., displays a variety of promising pharmacological activities, such as neuroprotection, enhancement of learning and memory, vascular protection and inhibition of platelet aggregation; therefore, it has been developed as a pharmaceutical for prevention or treatment of dementia. Given the safety concerns surrounding timosaponins and the absence of studies on the safety of TBII, the potential toxicity of TBII was evaluated in toxicity and toxicokinetic studies in rats. In the acute oral toxicity study, loose stools were observed in rats receiving 4000 mg/kg, and the symptoms recovered within 1 day. In the 28-day repeated-dose oral toxicity and toxicokinetic study, rats receiving 540 mg/kg showed loose stools and a slight deceleration of body weight growth in both sexes, and the females also showed a slight decrease in food consumption. Moreover, urinalysis indicated reversible treatment-related toxicity in rats receiving 540 mg/kg. The toxicokinetic study demonstrated a dose-dependent increase in systematic exposure to TBII after 28 successive days of oral treatment with TBII. The accumulation coefficients of TBII were 4.35, 1.70 and 1.81, respectively, in rats that received 60, 180 and 540 mg/kg. The no-observed-adverse-effect level (NOAEL) is proposed to be 180 mg/kg.  相似文献   

12.
Urine and serum biomonitoring was used to measure internal exposure to selected dietary estrogens in a cohort of 30 pregnant women. Exposure was measured over a period comprising one-half day in the field (6 h) and one day in a clinic (24 h). Biomonitoring of the dietary phytoestrogens genistein (GEN), daidzein (DDZ) and equol (EQ), as well as the mycoestrogen, zearalenone (ZEN) and its congeners, was conducted using UPLC-MS/MS. Biomonitoring revealed evidence of internal exposure to naturally occurring dietary estrogens during pregnancy. Urinary concentrations of total GEN, DDZ and EQ were similar to levels reported for general adult U.S. population. Measurable concentrations of total (parent and metabolites) GEN, DDZ and EQ were present in 240, 207 and 2 of 270 serum samples, respectively. Six out of 30 subjects had measurable concentrations of unconjugated GEN and/or DDZ in serum between 0.6 and 7.1 nM. Urine to serum total isoflavone ratios for GEN, DDZ and EQ were 13, 47, and 180, respectively. ZEN and its reductive metabolite, α-zearalenol (α-ZEL), were present in pregnant women (11 out of 30 subjects) as conjugates at levels near the limit of quantification. The average total urinary concentration was 0.10 μg/L for ZEN and 0.11 μg/L for α-ZEL.  相似文献   

13.
Koji products have been considered as an effective fermented food consumed in East Asia with many health benefits. Particularly, rice koji with Aspergillus terreus (RAT) has been reported to be able to prevent hyperlipidemia and hepatic steatosis through regulating cholesterol synthesis. Despite its biological activities, there is a lack of comprehensive information to give an assurance of its safety. Therefore, the objective of this study was to perform a series of toxicological studies (repeated dose oral toxicity and genotoxicity) according to test guidelines published by the Organization for Economic Cooperation and Development. Along with acute toxicity study using rats and beagle dogs, a 13-week toxicity study revealed no clear RAT-related toxic changes, including body weight, mortality, hematology, serum biochemistry, organ weight, and histopathology after oral administration at doses of 500, 1000, and 2000 mg/kg BW. The no-observed-adverse-effect level of RAT was considered to be more than 2000 mg/kg BW/day in rats of both genders. In addition, potential genotoxicity was evaluated using a standard battery of tests (Ames test, chromosome aberration assay, and micronucleus assay) which revealed that RAT showed no genotoxicity. Accordingly, these results suggest that RAT is a safe and non-toxic functional food for human consumption at proper dose.  相似文献   

14.
Despite its very low oral bioavailability and rapid elimination, multiple reports of unexpectedly high bisphenol A (BPA) concentrations in the serum of pregnant mothers or cord blood have raised questions about BPA exposures during pregnancy. Thirty healthy pregnant women recruited to the study were evaluated for total BPA exposure over a 30-h period comprising one-half day in the field and one day in a clinical setting. BPA and its metabolites were measured in serum and total BPA was measured in matching urine samples. The mean total exposure was similar to the 50th percentile of exposure for U.S. women and pregnant women in a large North American cohort. Twenty volunteers had total daily exposures equal to or exceeding the U.S. mean, and six volunteers had exposures exceeding the 75th percentile. Women working as cashiers did not have higher total BPA exposure. BPA was detected in some serum samples (0.25–0.51 ng/ml), but showed no relationship to total BPA in corresponding urine samples, no relationship to total BPA exposure, and had unconjugated BPA fractions of 60–80%, consistent with established criteria for sample contamination. We conclude that typical exposures of North American pregnant women produce internal exposures to BPA in the picomolar range.  相似文献   

15.
For agrochemicals tested in a carcinogenicity rodent study, it is often not possible to use the same high dose to achieve maximum tolerated dose (MTDs) without overdosing or insufficiently challenging one gender if significant gender differences are known. Toxicokinetic (TK) data for pesticide FR from a 28-day rat study showed that males required a 3-fold higher external dose compared to females to produce similar internal exposure levels of the parent compound. In the 90-day study, 8%/17% (M/F) decrease in bodyweight gain (BWG) and 15%/15% (M/F) increase in relative liver weights were observed in the 6000 ppm males and 2000 ppm females, respectively. Based on the above TK and toxicity data, different high dose levels were selected for females (1600 ppm) and males (4800 ppm) for a 2-year combined chronic/carcinogenicity study in rats. In the 2-year study, 14%, 13%, 13% and 21% reduction in BWG of males and 10%, 12%, 19% and 20% reduction in BWG of females were observed at weeks 13, 26, 52 and 104, respectively in the highest dose tested. Similar reductions in bodyweight gain in males and females at the different high dose levels clearly demonstrated that appropriate MTDs were reached. Therefore, it is scientifically sound and practical to use TK and toxicity data to use different high dose levels to achieve MTDs for a pesticide with large gender differences.  相似文献   

16.
Although an internationally-adopted in vitro dermal absorption test guideline is available (OECD Test Guideline 428), the replacement of the in vivo approach in North America for pesticide formulations has not occurred due to concern over the reliability and consistency of the in vitro results. A 2012 workshop convened a panel of experts in the conduct of in vitro studies used for pesticide risk assessment, together with North American regulators, to examine techniques for in vitro dermal absorption testing. Discussions led to the recommended “best practices” for the conduct of in vitro dermal absorption studies provided herein. The workshop participants also developed recommendations for reporting study results in order to improve the quality and consistency of the data submitted to regulatory agencies in North America. Finally, a case study is presented that illustrates the use of the “triple-pack” approach; the studies, conducted for the registration of sulfoxaflor, follow the standardized recommendations provided at the workshop. In addressing the concerns of these regulators and of the regulated community, and providing harmonized recommendations to facilitate comparative data analyses, it is anticipated that wider acceptance of in vitro dermal absorption studies alone can be achieved for pesticide risk assessment.  相似文献   

17.
Mycotoxins are secondary metabolites produced by fungi contaminating the food chain that are toxic to animals and humans. Children up to 12 years old are recognized as a potentially vulnerable subgroup with respect to consumption of these contaminants. Apart from having a higher exposure per kg body weight, they have a different physiology from that of adults. Therefore they may be more sensitive to neurotoxic, endocrine and immunological effects. For these reasons, a specific and up-to-date risk analysis for this category is of great interest.In this review, an accurate analysis of the main mycotoxins occurring in food intended for children (deoxynivalenol, aflatoxins, ochratoxins, patulin and fumonisins) is presented. In particular, known mechanisms of toxicity and levels of exposure and bioaccessibility in children are shown. In addition, recent discoveries about the strategies of mycotoxins managing are discussed.  相似文献   

18.
Microbial detoxification of deoxynivalenol (DON) represents a new approach to treating DON-contaminated grains. A bacterium Devosia mutans 17-2-E-8 was capable of completely transforming DON into a major product 3-epi-DON and a minor product 3-keto-DON. Evaluation of toxicities of these DON-transformation products is an important part of hazard characterization prior to commercialization of the biotransformation application. Cytotoxicities of the products were demonstrated by two assays: a MTT bioassay assessing cell viability and a BrdU assay assessing DNA synthesis. Compared with DON, the IC50 values of 3-epi-DON and 3-keto-DON were respectively 357 and 3.03 times higher in the MTT bioassay, and were respectively 1181 and 4.54 times higher in the BrdU bioassay. Toxicological effects of 14-day oral exposure of the B6C3F1 mouse to DON and 3-epi-DON were also investigated. Overall, there were no differences between the control (free of toxin) and the 25 mg/kg bw/day or 100 mg/kg bw/day 3-epi-DON treatments in body and organ weights, hematology and organ histopathology. However, in mice exposed to DON (2 mg/kg bw/day), white blood cell numbers and serum immunoglobulin levels were altered relative to controls, and lesions were observed in adrenals, thymus, stomach, spleen and colon. Taken together, in vitro and in vivo studies indicate that 3-epi-DON is substantially less toxic than DON.  相似文献   

19.
Through their diet, humans are exposed to a wide range of substances with possible adverse effects. Total diet studies (TDS) assess exposure and risk for many single substances or mixtures from the same chemical family.This research aims to identify from 440 substances in the second French TDS, the major mixtures to which the French population is exposed and their associated diet. Firstly, substances with a contamination value over the detection limit were selected. Secondly, consumption systems comprising major consumed foods were identified using non-negative matrix factorisation and combined with concentration levels to form the main mixture. Thirdly, individuals were clustered to identify “diet clusters” with similar consumption patterns and co-exposure profiles.Six main consumption systems and their associated mixtures were identified. For example, a mixture of ten pesticides, six trace elements and bisphenol A was identified. Exposure to this mixture is related to fruit and vegetables consumed by a diet cluster comprising 62% of women with a mean age of 51 years. Six other clusters are described with their associated diets and mixtures. Cluster co-exposures were compared to the whole population.This work helps prioritise mixtures for which it is crucial to investigate possible toxicological effects.  相似文献   

20.
Due to health concerns about safety, three UV-filters (Benzophenone-3, BP3, 10%; Ethylhexyl Methoxycinnamate, EHMC, 10%; Butyl Methoxydibenzoylmethane, BMDBM; 5%) were examined in vitro for absorption on full-thickness pig-ear skin, mimicking human in-use conditions. Kinetic profiles confirmed the rapid permeation of BP3; after the first hour of skin (frozen-stored) exposure to 2 mg/cm2 (W/O sunscreen; recommended but unrealistic amount), about 0.5% of the applied dose passed into the receptor fluid. The absorption rate of filters was higher from W/O than from O/W emulsions. The fresh/frozen-stored skin permeability coefficient (0.83–0.54) for each UV filter was taken into account. Systemic Exposure Dosage of BP3, EHMC, BMDBM for humans as a consequence of (i) whole-body and (ii) face treatment with 0.5 mg/cm2 of W/O sunscreen for 6-h skin exposure followed by washing and subsequent 18-h permeation (a realistic scenario) were estimated to be (i) 4744, 1032 and 1036 μg/kg-bw/day, and (ii) 153, 33 and 34 μg/kg-bw/day, respectively. From Margin of Safety for BP3, EHMC and BMDBM (i) 42, 485 and 192 as well as (ii) 1307; 15,151 and 5882, respectively, only the value of 42 (<100) for BP3 indicated a possible health risk. Escalation of a phobia towards all organic UV filters is undesirable.  相似文献   

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