Duplicate Diet Research Articles

Release of lead from bone in pregnancy and lactation

Concentrations and isotope ratios of lead in blood, urine, 24-h duplicate diets, and hand wipes were measured for 12 women from the second trimester of pregnancy until at least 8 months after delivery. Six bottle fed and six breast fed their infants. One bottle feeder fell pregnant for a second time, as did a breast feeder, and each was followed semicontinuously for totals of 44 and 54 months, respectively. Bone resorption rather than dietary absorption controls changes in blood lead, but in pregnancy the resorption of trabecular and cortical bone are decoupled. In early pregnancy, only trabecular bone (presumably of low lead content) is resorbed, causing blood leads to fall more than expected from hemodilution alone. In late pregnancy, the sites of resorption move to cortical bone of higher lead content and blood leads rise. In bottle feeders, the cortical bone contribution ceases immediately after delivery, but any tendency for blood leads to fall may be compensated by the effect of hemoconcentration produced by the postpartum loss of plasma volume. In lactation, the whole skeleton undergoes resorption and the blood leads of nursing mothers continue to rise, reaching a maximum 6–8 months after delivery. Blood leads fall from pregnancy to pregnancy, implying that the greatest risk of lead toxicity lies with first pregnancies.

Estimated daily intake of plasticizers in 1-week duplicate diet samples following regulation of DEHP-containing PVC gloves in Japan

Duplicate hospital diet samples obtained over 1 week in 2001 were analysed to estimate the daily intake of plasticizers and the results were compared with those obtained in 1999. The plasticizers quantified in this study were: dibutyl phthalate, butylbenzyl phthalate (BBP), di(2-ethylhexyl) phthalate (DEHP), diisononyl phthalate (DINP), di(2-ethylhexyl) adipate (DEHA), diisononyl adipate (DINA) and O-acetyl tributyl citrate (ATBC). Dipropyl, dipentyl, dihexyl and dicyclohexyl phthalate were also analysed but not detected. The analytical procedure for this follow-up study was essentially the same as in the previous one. Detection limits were 0.1–15.6 ng g-1 for each plasticizer. One-week duplicate diet samples provided by three hospitals in three remote prefectures of Japan were analysed as individual meals. DEHP was detected at 6–675 ng g-1 in 62 of 63 meals, significantly lower levels compared with those detected in 1999. Levels of DEHA and DINP also decreased. The mean intake of plasticizers estimated from all samples was 160 μg DEHP day-1, 12.5 μg DEHA day-1, 4.7 μg DINP day-1 and 3.4 μg BBP day-1. Levels of DINA were relatively high in meals from one hospital: in those meals, the average daily intake was 1338 μg day-1. Those of ATBC were also higher in meals from another hospital: the average daily intake was 1228 μg day-1. The sources of DINA and ATBC can be cling-film or sausage packaging.

Low-dose growth hormone in adult home parenteral nutrition–dependent short bowel syndrome patients: A positive study

Background & Aims: Controversy surrounds a 3-week treatment with a high-dose (0.14 mg · kg −1 · day −1) growth hormone (GH), glutamine, and high carbohydrate diet in home parenteral nutrition (HPN)-dependent patients with short-bowel syndrome (SBS). This study assessed treatment with low-dose GH in these patients. Methods: Twelve adult HPN-dependent (duration, 7 ± 1 years; mean ± SEM) patients with SBS (small-bowel remnant length, 48 ± 11 cm) who were on an unrestricted hyperphagic diet were randomized in a double-blind, placebo-controlled, crossover study. Patients received daily low-dose GH (0.05 mg · kg −1 · day −1) and placebo for two 3-week periods separated by a 1-week washout period. Net intestinal absorption of macronutrients was assessed using a duplicate diet; nutritional assessment and blood tests were performed. Data from each group were compared using Wilcoxon rank sum test. Results: Treatment with GH increased intestinal absorption of energy (15% ± 5%, P < 0.002), nitrogen (14% ± 6%, P < 0.04), carbohydrates (10% ± 4%, P < 0.04), and fat (12% ± 8%, NS). The increased food absorption represented 37% ± 16% of total parenteral energy delivery. Body weight ( P < 0.003), lean body mass ( P < 0.006), D-xylose absorption ( P < 0.02), insulin-like growth factor 1 ( P < 0.002), and insulin-like growth factor binding protein 3 ( P < 0.002) increased, whereas uptake of GH binding protein decreased ( P < 0.01), without any major adverse effect. Conclusions: Three weeks of low-dose GH significantly improved intestinal absorption in HPN-dependent SBS patients who were on a hyperphagic western diet.

Levels of phytoestrogens, inorganic trace-elements, natural toxicants and nitrate in vegetarian duplicate diets

Vegetarian duplicate diets were collected in summer (16) and winter (19) and were analysed for the levels of 13 phytoestrogens, nitrate, 12 trace elements, two glycoalkaloids and three furanocoumarins. Phytoestrogens were analysed by paired hydrolysed and non-hydrolysed assays. The mean total isoflavone concentration in diets, without hydrolysis, was 14 mg kg −1 in summer and 15 mg kg −1 in winter, corresponding to an overall hydrolysed aglycone concentration of 10 mg kg −1. The tin concentration was higher in winter than in summer diets at 4.6 and 2.2 mg kg −1. The nitrate concentration was 51 mg kg −1 in summer and 45 mg kg −1 in winter. The furanocoumarins psoralen, xanthotoxin and bergapten were present at a combined average concentration of 0.075 mg kg −1. The glycoalkaloid α-chaconine was observed in only one sample at 14 mg kg −1 with an LOD of 0.8 mg kg −1. Only minor compositional differences were observed between the summer and winter diets. Daily intakes were calculated and these values were compared with existing compositional data on food and with the appropriate recommended safe exposure levels. For isoflavones a mean aglycone equivalent intake of 10.5 mg day −1 was calculated. The mean tin intake was significantly higher in winter than in summer at 5.5 and 2.1 mg day −1. Nitrate intake from these diets was 53 mg day −1, if the theoretical liquid portion of diet were considered, the resulting estimated total of 84 mg day −1 is similar to that of the UK average. Other than an increase in tin intake during winter, exposure of vegetarians to individual phytoestrogens, natural toxicants and inorganic trace-elements was comparable to that of the general population. No individual level of any analyte in any single diet sample exceeded recommended intake levels.

Sensitive method for the determination of nitrated polycyclic aromatic hydrocarbons in the human diet.

The presence of nitrated polycyclic aromatic hydrocarbons (nitro-PAHs) as contaminants in foods is nowadays a legitimate cause of concern, as they are reported to be strong direct-acting mutagens and carcinogens that may pose a risk to human health. Nevertheless, their concentrations in foods are in the ultra-trace region. In this study, we present a very sensitive analytical method for the determination of this compound class in complex food matrices. Special emphasis was put on sample extraction and clean up. Recoveries of 75% could be obtained for 1- and 2-nitronaphthalene; for all other compounds investigated the recoveries were >/=94%. The determination of the compounds was performed by gas chromatography-mass spectrometry. The results show that the use of negative chemical ionization (NCI) increases the sensitivity by one order of magnitude in comparison to electron impact ionization (EI) (limits of detection 0.07-0.25 micro g kg(-1) for EI and 0.01-0.02 micro g kg(-1) for NCI). The influence of the sample matrix on the sensitivity of the method is demonstrated with extracts of a sample from a duplicate diet study. Due to the lack of a certified reference material the suitability of the method is demonstrated with pumpkin seed oil that was spiked with nitro-PAHs at two different concentration levels.

Estimation of iron, copper, zinc and manganese intake from duplicate diets provided by hospitals in Poland, 1993-96

Daily intakes of iron (Fe), copper (Cu), zinc (Zn) and manganese (Mn) from whole-day food rations composed by dieticians and collected in hospital canteens in Krakow, Lodz, Olsztyn and Poznan, Poland, in the winters of 1993/94, 1995 and 1996, were determined by atomic absorption spectrometry. The average intake of Fe, 14 mg day-1, was satisfactory for both women and men; 13 mg Zn fulfilled the safe level for women (taken as the recommended minimum level to meet the needs of 97.5% of the population) but it was too low for men, and 1.3 mg Cu corresponded to 65–72% of the safe level set for this microelement in Poland. There is no recommended level set in Poland for Mn, but compared with recommended levels in Germany and the USA, the determined daily Mn intake equal to 3.7 mg should be sufficient. Statistical analysis confirmed higher amounts of Zn and Mn in diets collected in Krakow, higher Cu content in diets from 1996, and lower Mn content in food collected in 1995.

Determination of selenium balance in healthy children by aas-hydride generation and by inaa technique

Total daily Se intake was determined by duplicate diet collection, venous blood samples were taken and urine was collected over 24 h in order to measure selenium input and output in healthy, American and Hungarian children aged 8 to 17 living in Budapest. The American children consumed not only locally processed food. Food samples were weighed, mixed, homogenised and the Se content was determined by Instrumental neutron activation analysis (INAA). The Se concentration of blood, plasma and urine samples was determined by atomic absorption spectrometry-hydride generation (AAS-HG) after wet digestion. Se intake calculated for wet weight was 62±18.5 mg/day in American children. In the Hungarian children the mean Se intake was about 35% less than in the Americans. Se concentrations in plasma were 0.84±0.16, in whole blood 1.13±0.17 mmol l-1 in the Americans, higher than those in healthy Hungarian children (0.64±0.10 and 0.83±0.12 mmol l-1, respectively) of similar age and gender. Urinary Se output calculated ...

Analysis of aggregate exposure to chlorpyrifos in the NHEXAS-Maryland investigation.

As part of the National Human Exposure Assessment Survey (NHEXAS) in Maryland, we collected indoor air, carpet dust, exterior soil, and duplicate diet samples from a stratified random sample of 80 individuals to evaluate aggregate daily exposure, contributions of specific pathways of exposure, and temporal variation in exposure to chlorpyrifos. We collected samples from each participant in up to six equally spaced sampling cycles over a year and analyzed them for chlorpyrifos. We used chlorpyrifos concentrations in each medium and self-reported rates of time spent inside at home, time and frequency of contact with carpet, frequency of contact with soil, and weights of the duplicate diet samples to derive exposure to chlorpyrifos from each medium as well as average daily aggregate exposure (nanograms per day). The mean aggregate daily exposure to chlorpyrifos of 36 measurements obtained from 31 people was 1,390 ng/day (SD, 2,770 ng/day). Exposure from inhalation of indoor air accounted for 84.7% of aggregate daily exposure to chlorpyrifos on average. Chlorpyrifos concentrations in indoor air and carpet dust and the corresponding exposure rates were significantly correlated. Repeated short-term measurements of chlorpyrifos in carpet dust from individual residences were strongly correlated over time (reliability coefficient, R = 0.90), whereas the short-term measurements of chlorpyrifos in indoor air (R = 0.55) and solid food (R = 0.03) had moderate to weak reliability. Exposure to chlorpyrifos through those media and in aggregate based on direct measurements reported in this study can be used to understand better the accuracy of pesticide safety assessments.

Dietary Intake of Essential Minor and Trace Elements from Asian Diets

In view of the limited data available from the Asian region on the daily intake of nutritionally essential trace elements, a study was taken up, as part of a coordinated research project of the International Atomic Energy Agency, to estimate the daily dietary intake and organ content of some selected trace elements of importance in radiation protection, and also in nutrition. Nine Asian countries--Bangladesh, China, India, Indonesia, Japan, South Korea, Pakistan, Philippines, and Vietnam--which represented more than 50% of the world's population, participated in this study. Analysis of about 700 diet samples was carried out for four minor (calcium, potassium, magnesium, and sodium) and eight trace (chromium, cobalt, copper, iron, iodine, manganese, selenium, and zinc) elements using nuclear and other sensitive analytical methods employing neutron activation analysis (NAA), inductively coupled plasma mass spectrometry (ICP-MS), inductively coupled plasma atomic emission spectrometry (ICP-AES), and atomic absorption spectrometry (AAS) techniques. These samples consisted of the total cooked diet, market basket, duplicate diets, and 225 staple foods. Emphasis was placed on the quality assurance and harmonization of the sampling techniques to ensure quality data. Significant inter- and intra-country variations in daily dietary intake of various trace elements were observed. The maximum inter-country variation was observed for iodine intake (factor of more than 45), being highest for Japan and lowest for Pakistan. For iron, an important trace element, the variation between the intakes was by a factor of four being lowest for Vietnam and highest for Pakistan.

Assessment of dietary exposure to ochratoxin A in the UK using a duplicate diet approach and analysis of urine and plasma samples

The approach to assess exposure to ochratoxin A from the diet by the analysis of human plasma and urine samples has been developed. Composite duplicate diet samples from 50 individuals and corresponding plasma and urine samples were obtained over 30 days. Samples were analysed using sensitive methods capable of measuring ochratoxin A at 0.001ng g -1 in food, 0.1ng ml -1 in plasma and 0.01ng ml -1 in urine. Analysis of the foods indicated ochratoxin A levels contributing to an average intake in the range 0.26-3.54ng kg -1 bw day -1 over the 30 days. Ochratoxin A was found in all plasma samples and in 46 urine samples. The correlation between the plasma ochratoxin A levels and ochratoxin A consumption was not significant (95% confidence limit). However, a significant correlation was found between ochratoxin A consumption and the urine ochratoxin A concentration expressed as the total amount excreted. This new work offers the possibility of using ochratoxin A in urine as a simple and reliable biomarker to estimate exposure to this mycotoxin.

Total Fluoride Intake and Urinary Excretion in German Children Aged 3–6 Years

There have only been few investigations comparing total fluoride intake and the fluoride proportion excreted in urine in pre–school children. In addition, the results of available studies are conflicting. Total fluoride intake was assessed in 11 healthy children aged 3–6 years on 2 consecutive days and urinary fluoride excretion was determined. The duplicate–diet approach was used for the assessment of fluoride intake from solid and liquid foods. Fluoride intake from toothbrushing was calculated as the difference between the amount of fluoride in the paste put on the toothbrush and the drinking water (fluoride concentration 0.25 mg/l) used for rinsing vs. the fluoride amounts recovered in the toothpaste spat out and in the rinsing water. Use of fluoridated domestic salt and/or fluoride tablets was recorded. The children’s intake of fluoride from food averaged 202.5±116.2 µg F/day. They swallowed an average amount of 273.9±175.6 µg F/day when brushing their teeth. Daily fluoride ingestion from all sources totalled 930.7±391.5 µg or 53.0±21.4 µg/kg body weight. On average 51.5% of the fluoride ingested was excreted in urine. The wide interindividual variation makes it necessary to evaluate the urinary excretion rate for fluoride in larger study populations with varied fluoride exposure.

Dietary Intakes of Selected Elements from Longitudinal 6-Day Duplicate Diets for Pregnant and Nonpregnant Subjects and Elemental Concentrations of Breast Milk and Infant Formula

As part of a longitudinal investigation into mobilization of lead from the maternal skeleton during pregnancy and lactation, we have determined the daily intake of selected elements (hereafter called micronutrients) for various subjects and compared these intakes with recommended and/or published intakes, especially those of the United States, through the U.S. National Health and Nutrition Examination Survey (NHANES). We also sought to ascertain whether there was any seasonal effect in the diets. Six-day duplicate diets were collected from 15 pregnant and 16 nonpregnant migrants to Australia, 6 pregnant Australian control subjects, and 8 children of nonpregnant migrants (6 to 11 years). Samples of breast milk and infant formula were also analyzed. Blended samples were analyzed by inductively coupled plasma mass spectrometry for the elements Ca, Cu, Fe, Mg, P, K, Na, Zn, Ba, Sr, and Pb. Daily intakes of micronutrients were only about half of the daily intake estimated for non-Hispanic white females and infants in the U.S. NHANES III. Estimates of daily intakes from breast milk were also considerably lower for the migrant and Australian infants compared with the values extracted from tables of food composition and dietary recall for non-Hispanic white infants in the U.S. NHANES III. For example, Ca was a factor of ∼3 times lower, Fe ∼50, and Zn ∼4. We consider our estimates a reliable indication of the daily intakes for several reasons, including the collection of up to nine quarterly collections of 6-day duplicate diets and retention of subjects in a longitudinal prospective study. The low intakes of the essential elements such as Ca, Fe, and Zn in all these population groups are of potential concern from a public health viewpoint.

Contribution of children's activities to lead contamination of food.

This study evaluates the relationship of children's hygiene habits and food-handling behaviors on lead levels on hands and handled foods for toddlers living in lead-contaminated homes. Forty-eight inner city toddlers previously identified as having elevated blood lead levels participated in three consecutive days of designated food-handling activities. During the visits, duplicate diets were obtained, the child handled a banana, a hot dog, and had his/her hands wiped with a moist towelette. In addition, wipe samples were collected from the kitchen floor, and food items were deposited on and subsequently collected from the kitchen floor. All samples were analyzed for lead. The child's caregiver completed a questionnaire, which addressed the child's hygiene and eating behaviors. It was demonstrated that children's contact with residential dust containing lead can transfer lead to food. Both lead in the home and on the children's hands contribute to the contamination of food, and hence potential dietary exposure. Mean lead in handled bananas was 26 microg/kg and on hot dogs 65 microg/kg, and mean lead values on cheese and apple slices that had been on the floor were 119 and 215 microg/kg. In addition, the child's hygiene habits as reported by the parent indicate that lack of basic hygiene patterns within a high lead environment can contribute to children's dietary exposure to lead.

Daily dietary intake of chromium in southern Spain measured with duplicate diet sampling.

We measured daily dietary Cr intake in southern Spain by sampling duplicate diets for seven consecutive days in different population groups. Cr was determined by electrothermal atomization-atomic absorption spectrometry. The samples were mineralized in a digestion block with HNO(3), HClO(4) and V(2)O(5). A total of 161 duplicate diets from twenty-three subjects were analysed, and mean levels of Cr intake ranged from 9.39 to 205.16 microg/d. Mean Cr intake (100 microg/d) was similar to levels found for most other countries, and was within the range recommended by the National Research Council for a safe and adequate daily intake (50-200 microg/d). Chromium intake correlated significantly with energy, protein and carbohydrate intake, and with the daily intake of Zn, Fe, Mg, K, Na, Ca and nicotinic acid in the diets analysed.

Estimation of chromium bioavailability from the diet by an in vitro method

An in vitro method was used to study the dialysable fraction of chromium (Cr) from the diet which simulates human gastric and intestinal digestion. The percentage of dialysed Cr was used to assess the bioavailability. The duplicate diet approach was used to obtain ten different sets of samples each representative of the normal diet consumed in southern Spain. In each case triplicate analysis of Cr was carried out by electrothermal atomization-atomic absorption spectrometry in acid-mineralized samples. The Cr dietary intake ranged from 16 to 117 μg/day, and the dialysable Cr fraction ranged from 0.4% to 1.6%. The Cr absorption was higher for low levels of daily dietary mu intake of Cr (lt; 40 μg) than for levels of 40–80 μg; for mu high levels (> 80 μg) there was an increase in the dialysable fraction. The energy and nutrient intake of these diets was also evaluated.

Eleven phthalate esters and di(2-ethylhexyl) adipate in oneweek duplicate diet samples obtained from hospitals and their estimated daily intake

Plasticizers in duplicate diet samples obtained over 1 week were analysed in order to estimate daily intake. The phthalate esters were as follows: diethyl, dipropyl, dibutyl, dipentyl, dihexyl, butylbenzyl, dicyclohexyl, di(2-ethylhexyl), dioctyl, diisooctyl (mixture of isomers) and diisononyl (mixture). Di(2-ethylhexyl) adipate was also determined. Homogenized samples of composite meals were extracted with acetonitrile, lipids were removed by extraction into n-hexane and the acetonitrile layer was cleaned using FlorisilR and Bondesil PSAR dual layer column. Phthalates were determined by GC/MS (SIM). Phthalate recovery from the fortified food mixture by this method was 62.5–140.8%. Quality assurance as assessed by three laboratories indicated coefficient of variance in the levels of detected phthalates in same lot samples as below 10%. Detection limits were 0.1–23ng/g for each phthalate. One-week duplicate diet samples provided by three hospitals in three remote prefectures of Japan were analysed as individual meals. In all 63 samples, DEHP was present at the highest level among all phthalates in the range 10–4400ng/g. The intake of plasticizers estimated from all samples was 519 μg DEHP/day, 86 μg DEHA/day, 65 μg DINP/day, and 4.7 μg BBP/day. Calculated DEHP in 2-day samples out of 21 days exceeded EU TDI for a person of 50kg body weight (1850 μg per day). Disposable PVC gloves used during the preparation of meals were suspected as the source of the high DEHP content. One-day intake of the other phthalates and DEHA was below 7% of TDI in all cases. High concentrations of DEHP (5990ng/g) was found in baby food used in quality assurance work. The source of contamination was the PVC-tube used during production and was effectively reduced by replacing the tube by one made of stainless steel.

Eleven phthalate esters and di(2-ethylhexyl) adipate in oneweek duplicate diet samples obtained from hospitals and their estimated daily intake

Plasticizers in duplicate diet samples obtained over 1 week were analysed in order to estimate daily intake. The phthalate esters were as follows: diethyl, dipropyl, dibutyl, dipentyl, dihexyl, butylbenzyl, dicyclohexyl, di(2-ethylhexyl), dioctyl, diisooctyl (mixture of isomers) and diisononyl (mixture). Di(2-ethylhexyl) adipate was also determined. Homogenized samples of composite meals were extracted with acetonitrile, lipids were removed by extraction into n-hexane and the acetonitrile layer was cleaned using FlorisilR and Bondesil PSAR dual layer column. Phthalates were determined by GC/MS (SIM). Phthalate recovery from the fortified food mixture by this method was 62.5–140.8%. Quality assurance as assessed by three laboratories indicated coefficient of variance in the levels of detected phthalates in same lot samples as below 10%. Detection limits were 0.1–23ng/g for each phthalate. One-week duplicate diet samples provided by three hospitals in three remote prefectures of Japan were analysed as individual meals. In all 63 samples, DEHP was present at the highest level among all phthalates in the range 10–4400ng/g. The intake of plasticizers estimated from all samples was 519 μg DEHP/day, 86 μg DEHA/day, 65 μg DINP/day, and 4.7 μg BBP/day. Calculated DEHP in 2-day samples out of 21 days exceeded EU TDI for a person of 50kg body weight (1850 μg per day). Disposable PVC gloves used during the preparation of meals were suspected as the source of the high DEHP content. One-day intake of the other phthalates and DEHA was below 7% of TDI in all cases. High concentrations of DEHP (5990ng/g) was found in baby food used in quality assurance work. The source of contamination was the PVC-tube used during production and was effectively reduced by replacing the tube by one made of stainless steel.

Contribution of lead from calcium supplements to blood lead.

We conducted a case-control study to determine the contribution of lead to blood from consumption of calcium supplements approximating the recommended daily intakes over a 6-month period. Subjects were males and females ages 21 to 47 years (geometric mean 32 years) with a geometric mean blood lead concentration of 2.5 microg/dL. They were subdivided into three groups. One treatment group (n = 8) was administered a complex calcium supplement (carbonate/phosphate/citrate) and the other treatment group (n = 7) calcium carbonate. The control group (n = 6) received no supplement. The lead isotopic compositions of the supplements were completely different from those of the blood of the subjects, allowing us easily to estimate contribution from the supplements. The daily lead dose from the supplements at 100% compliance was about 3 microg Pb. Three blood samples were taken at 2-month intervals before treatment to provide background values, and three were taken during treatment. Subjects in the treatment group were thus their own controls. Lead isotopic compositions for the complex supplement showed minimal change during treatment compared with pretreatment. Lead isotopic compositions in blood for the calcium carbonate supplement showed increases of up to 0.5% in the (206)Pb/(204)Pb ratio, and for all isotope ratios there was a statistically significant difference between baseline and treatment (p < 0.005). The change from baseline to treatment for the calcium carbonate supplement differed from that for both the control group and the group administered the complex supplement. Blood lead concentrations, however, showed minimal changes. Variations in blood lead levels over time did not differ significantly between groups. Our results are consistent with earlier investigations using radioactive and stable lead tracers, which showed minimal gastrointestinal absorption of lead in the presence of calcium (+/- phosphorus) in adults. Even though there is no discernible increase in blood lead concentration during treatment, there are significant changes in the isotopic composition of lead in blood arising from the calcium carbonate supplement, indicating a limited input of lead from diet into the blood. Because calcium carbonate is overwhelmingly the most popular calcium supplement, the changes we have observed merit further investigation. In addition, this type of study, combined with a duplicate diet, needs to be repeated for children, whose fractional absorption of lead is considerably higher than that of adults.

Metabolites of Pyrethroid Insecticides in Urine Specimens: Current Exposure in an Urban Population in Germany

Pyrethroids are important insecticides used in agriculture, forestry, horticulture, and in the home. In humans, they are rapidly metabolized and renally eliminated. In numerous studies, pyrethroid metabolites have been detected in urine after occupational exposure to insecticides. In this study, we used a new, reliable, easy, and sensitive analytical method to assess the internal pyrethroid exposure of an urban population without exposure to pyrethoids at home or at work (children and adults). A total of 1,177 persons took part in this investigation, including 331 children under 6 years of age and 247 children between 6 and 12 years of age. None of them reported exposure to pyrethroids at home or at work. Accordingly, the levels of permethrin found in household dust from their homes were lower than expected (median &lt; limit of detection; 95th percentile, 4.8 mg/kg; maximum value, 19 mg/kg). Urine specimens were analyzed for cis-3-(2,2-dibromo-vinyl)-2,2-dimethylcyclo-propanecarboxylic acid (Br(2)CA), cis- and trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane-carboxylic acid (cis-Cl(2)CA and trans-Cl(2)CA), and 4-fluoro-3-phenoxybenzoic acid (F-PBA) using a gas chromatographic method with mass-selective detection. The limit of detection for pyrethroid metabolites was between 0.1 and 0.2 microg/L. trans-Cl(2)CA was detected in 65% of the urine specimens tested, cis-Cl(2)CA was detected in 30%, and Br(2)CA and F-PBA were found in 19% and 16%, respectively, of the urine specimens. The urinary metabolite levels in children did not differ from those in adults, and there was no correlation between the levels of metabolites and indoor exposure to permethrin in household dust. Moreover, no seasonal correlations could be found. The 95th percentile levels in urine specimens were as follows: Br(2)CA, 0.30 microg/L; cis-Cl(2)CA, 0.51 microg/L; trans-Cl(2)CA, 1.43 microg/L; F-PBA, 0.27 microg/L. Background exposure to pyrethroids was found in the general population; it seems to be caused by the uptake of pyrethroids with the diet. This hypothesis needs to be tested in duplicate diet studies combined with biomonitoring. As long as representative data are lacking, however, the rounded 95th percentile values obtained in our study may be used as reference values for pyrethroid metabolites in urine samples from the population in Germany; 95th percentile values for children and adults are as follows: Br(2)CA, 0.3 microg/L; cis-Cl(2)CA, 0.5 microg/L; trans-Cl(2)CA, 1.5 microg/L; and F-PBA, 0.3 microg/L.

Metabolites of pyrethroid insecticides in urine specimens: current exposure in an urban population in Germany.

Pyrethroids are important insecticides used in agriculture, forestry, horticulture, and in the home. In humans, they are rapidly metabolized and renally eliminated. In numerous studies, pyrethroid metabolites have been detected in urine after occupational exposure to insecticides. In this study, we used a new, reliable, easy, and sensitive analytical method to assess the internal pyrethroid exposure of an urban population without exposure to pyrethoids at home or at work (children and adults). A total of 1,177 persons took part in this investigation, including 331 children under 6 years of age and 247 children between 6 and 12 years of age. None of them reported exposure to pyrethroids at home or at work. Accordingly, the levels of permethrin found in household dust from their homes were lower than expected (median < limit of detection; 95th percentile, 4.8 mg/kg; maximum value, 19 mg/kg). Urine specimens were analyzed for cis-3-(2,2-dibromo-vinyl)-2,2-dimethylcyclo-propanecarboxylic acid (Br(2)CA), cis- and trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane-carboxylic acid (cis-Cl(2)CA and trans-Cl(2)CA), and 4-fluoro-3-phenoxybenzoic acid (F-PBA) using a gas chromatographic method with mass-selective detection. The limit of detection for pyrethroid metabolites was between 0.1 and 0.2 microg/L. trans-Cl(2)CA was detected in 65% of the urine specimens tested, cis-Cl(2)CA was detected in 30%, and Br(2)CA and F-PBA were found in 19% and 16%, respectively, of the urine specimens. The urinary metabolite levels in children did not differ from those in adults, and there was no correlation between the levels of metabolites and indoor exposure to permethrin in household dust. Moreover, no seasonal correlations could be found. The 95th percentile levels in urine specimens were as follows: Br(2)CA, 0.30 microg/L; cis-Cl(2)CA, 0.51 microg/L; trans-Cl(2)CA, 1.43 microg/L; F-PBA, 0.27 microg/L. Background exposure to pyrethroids was found in the general population; it seems to be caused by the uptake of pyrethroids with the diet. This hypothesis needs to be tested in duplicate diet studies combined with biomonitoring. As long as representative data are lacking, however, the rounded 95th percentile values obtained in our study may be used as reference values for pyrethroid metabolites in urine samples from the population in Germany; 95th percentile values for children and adults are as follows: Br(2)CA, 0.3 microg/L; cis-Cl(2)CA, 0.5 microg/L; trans-Cl(2)CA, 1.5 microg/L; and F-PBA, 0.3 microg/L.