Carol S. Rubin

Antimicrobial residues in animal waste and water resources proximal to large-scale swine and poultry feeding operations

Expansion and intensification of large-scale animal feeding operations (AFOs) in the United States has resulted in concern about environmental contamination and its potential public health impacts. The objective of this investigation was to obtain background data on a broad profile of antimicrobial residues in animal wastes and surface water and groundwater proximal to large-scale swine and poultry operations. The samples were measured for antimicrobial compounds using both radioimmunoassay and liquid chromatography/electrospray ionization-mass spectrometry (LC/ESI-MS) techniques. Multiple classes of antimicrobial compounds (commonly at concentrations of > 100 microg/l) were detected in swine waste storage lagoons. In addition, multiple classes of antimicrobial compounds were detected in surface and groundwater samples collected proximal to the swine and poultry farms. This information indicates that animal waste used as fertilizer for crops may serve as a source of antimicrobial residues for the environment. Further research is required to determine if the levels of antimicrobials detected in this study are of consequence to human and/or environmental ecosystems. A comparison of the radioimmunoassay and LC/ESI-MS analytical methods documented that radioimmunoassay techniques were only appropriate for measuring residues in animal waste samples likely to contain high levels of antimicrobials. More sensitive LC/ESI-MS techniques are required in environmental samples, where low levels of antimicrobial residues are more likely.

Serum follicle-stimulating hormone and luteinizing hormone levels in women aged 35-60 in the U.S. population: the Third National Health and Nutrition Examination Survey (NHANES III, 1988-1994).

OBJECTIVE The objective of this study was to examine age-specific population-based values for serum follicle-stimulating hormone (FSH) and luteinizing hormone (LH) levels in women in the U.S. population. DESIGN Data were collected from a nationally representative cross-sectional health examination survey that included measurements of follicle-stimulating hormone and luteinizing hormone and information from a personal interview. A total of 3388 women aged 35 to 60 years were examined during the third National Health and Nutrition Examination Survey, 1988-1994. RESULTS Among U.S. women aged 35-60 years, median FSH and LH levels began to increase for women in their late 40s and reached a plateau for women in their early 50s. This study supports the previously reported association between serum FSH and age (i.e., serum FSH and LH levels increase with age) and smoking (i.e., current smoking was associated with an increased level of serum FSH). At FSH levels of > or = 15 IU/L or > or = 20 IU/L. 70 and 73% of women, respectively, were postmenopausal. Our study also found an interaction between age and oophorectomy. In addition, the present data suggest that women with only one ovary may have higher FSH levels than women with both of their ovaries. CONCLUSIONS NHANES III provides population-based data that support previously reported associations between serum FSH level and age, smoking, and menopausal status.

Genetic Studies of a Cluster of Acute Lymphoblastic Leukemia Cases in Churchill County, Nevada

Objective In a study to identify exposures associated with 15 cases of childhood leukemia, we found levels of tungsten, arsenic, and dichlorodiphenyldichloroethylene in participants to be higher than mean values reported in the National Report on Human Exposure to Environmental Chemicals. Because case and comparison families had similar levels of these contaminants, we conducted genetic studies to identify gene polymorphisms that might have made case children more susceptible than comparison children to effects of the exposures. Design We compared case with comparison children to determine whether differences existed in the frequency of polymorphic genes, including genes that code for enzymes in the folate and purine pathways. We also included discovery of polymorphic forms of genes that code for enzymes that are inhibited by tungsten: xanthine dehydrogenase, sulfite oxidase (SUOX gene), and aldehyde oxidase. Participants Eleven case children were age- and sex-matched with 42 community comparison children for genetic analyses. Twenty parents of case children also contributed to the analyses. Results One bilalleleic gene locus in SUOX was significantly associated with either case or comparison status, depending on which alleles the child carried (without adjusting for multiple comparisons). Conclusions Although genetic studies did not provide evidence that a common agent or genetic susceptibility factor caused the leukemias, the association between a SUOX gene locus and disease status in the presence of high tungsten and arsenic levels warrants further investigation. Relevance Although analyses of community clusters of cancer have rarely identified causes, these findings have generated hypotheses to be tested in subsequent studies.

Perchlorate exposure from infant formula and comparisons with the perchlorate reference dose

Perchlorate exposure may be higher in infants compared with older persons, due to diet (infant formula) and body weight versus intake considerations. Our primary objective was to quantitatively assess perchlorate concentrations in commercially available powdered infant formulas (PIFs). Secondary objectives were: (1) to estimate exposure in infants under different dosing scenarios and compare them with the perchlorate reference dose (RfD); (2) estimate the perchlorate concentration in water used for preparing PIFs that would result in a dose exceeding the RfD; and (3) estimate iodine intakes from PIFs. We quantified perchlorate levels in three samples (different lot numbers) of reconstituted PIF (using perchlorate-free water) from commercial brands of PIF in each of the following categories: bovine milk-based with lactose, soy-based, bovine milk-based but lactose-free, and elemental (typically consisting of synthetic amino acids). Exposure modeling was conducted to determine whether the RfD might be exceeded in 48 dosing scenarios that were dependent on age, centile energy intake per unit of body weight, body weight percentile, and PIF perchlorate concentration. We obtained three different samples in each of the five brands of bovine- and soy-based PIF, three different samples in each of the three brands of lactose-free PIF, and three different samples in two brands of elemental PIF. The results were as follows: bovine milk-based with lactose (1.72 μg/l, range: 0.68–5.05); soy-based (0.21 μg/l, range: 0.10–0.44); lactose-free (0.27 μg/l, range: 0.03–0.93); and elemental (0.18 μg/l, range: 0.08–0.4). Bovine milk-based PIFs with lactose had a significantly higher concentration of perchlorate (P<0.05) compared with all. Perchlorate was a contaminant of all commercially available PIFs tested. Bovine milk-based PIFs with lactose had a significantly higher perchlorate concentration perchlorate than soy, lactose-free, and elemental PIFs. The perchlorate RfD may be exceeded when certain bovine milk-based PIFs are ingested and/or when PIFs are reconstituted with perchlorate-contaminated water.

Investigation of the relation between self-reported food consumption and household chemical exposures with urinary levels of selected nonpersistent pesticides †

Concerns about pesticide exposure through food consumption have increased during the past several years. The main objective of our study was to determine whether we could use data from the Third National Health and Nutrition Examination Survey (NHANES III) to detect a relation between self-reported food consumption — particularly consumption of fruits, vegetables, and bread products — and urinary levels of pesticides or their metabolites in a population of 978 adults living in the US. A secondary objective was to investigate whether these urine levels differed for people who reported exposure to selected common household chemicals including bug or insect spray, weed killer, and mothballs or crystals. We used monthly food frequency data from the NHANES III, 1988–1994. Urinary pesticide/metabolite levels and information about chemical exposures were taken from the Priority Toxicant Reference Range Study (a component of the NHANES III). Six pesticides or their metabolites were detected in at least 50% of the sample, three of which — 1-naphthol (86.4%), pentachlorophenol (62.5%), and 3,5,6-trichloro-2-pyridinol (82.0%) — were possibly related to food consumption. We were unable to detect a relation between self-reported food consumption and their urinary levels. This may be due more to the limitations of the datasets than to a lack of a relation between food consumption and urine pesticide/metabolite levels. We did find that people who reported recently using selected common chemicals had higher geometric mean urine pesticide/metabolite levels than did people who reported not recently using these chemicals.

Medication-associated diethylene glycol mass poisoning: a review and discussion on the origin of contamination.

Diethylene glycol (DEG), an extremely toxic chemical, has been implicated as the etiologic agent in at least 12 medication-associated mass poisonings over the last 70 years. Why DEG mass poisonings occur remains unclear. Most reports do not contain detailed reports of trace-back investigations into the etiology. The authors, therefore, conducted a systematic literature review on potential etiologies of these mass poisonings. The current available evidence suggests that substitution of DEG or DEG-containing compounds for pharmaceutical ingredients results from: (1) deception as to the true nature of certain ingredients by persons at some point in the pharmaceutical manufacturing process, and (2) failure to adhere to standardized quality control procedures in manufacturing pharmaceutical products intended for consumers. We discuss existing guidelines and new recommendations for prevention of these incidents.

Menstrual function among women exposed to polybrominated biphenyls: A follow-up prevalence study

BackgroundAlteration in menstrual cycle function is suggested among rhesus monkeys and humans exposed to polybrominated biphenyls (PBBs) and structurally similar polychlorinated biphenyls (PCBs). The feedback system for menstrual cycle function potentially allows multiple pathways for disruption directly through the hypothalamic-pituitary-ovarian axis and indirectly through alternative neuroendocrine axes.MethodsThe Michigan Female Health Study was conducted during 1997–1998 among women in a cohort exposed to PBBs in 1973. This study included 337 women with self-reported menstrual cycles of 20–35 days (age range: 24–56 years). Current PBB levels were estimated by exponential decay modeling of serum PBB levels collected from 1976–1987 during enrollment in the Michigan PBB cohort. Linear regression models for menstrual cycle length and the logarithm of bleed length used estimated current PBB exposure or enrollment PBB exposure categorized in tertiles, and for the upper decile. All models were adjusted for serum PCB levels, age, body mass index, history of at least 10% weight loss in the past year, physical activity, smoking, education, and household income.ResultsHigher levels of physical activity were associated with shorter bleed length, and increasing age was associated with shorter cycle length. Although no overall association was found between PBB exposure and menstrual cycle characteristics, a significant interaction between PBB exposures with past year weight loss was found. Longer bleed length and shorter cycle length were associated with higher PBB exposure among women with past year weight loss.ConclusionThis study suggests that PBB exposure may impact ovarian function as indicated by menstrual cycle length and bleed length. However, these associations were found among the small number of women with recent weight loss suggesting either a chance finding or that mobilization of PBBs from lipid stores may be important. These results should be replicated with larger numbers of women exposed to similar lipophilic compounds.

Pesticide exposure resulting from treatment of lice infestation in school-aged children in Georgia

OBJECTIVE The objective of this study was to assess pesticide exposures in children being treated for head lice with either lindane or permethrin (exposed group) and children who did not have a lice infestation and thus were not being treated with chemicals for head lice or scabies (unexposed group). METHODS In 2001, we enrolled 78 children aged 6-10 years old and collected baseline urine samples and demographic information from all the children. We subsequently collected post-exposure urine samples and questionnaire information about lice treatment from the 29 (37%) children (exposed children) who had been diagnosed and were being treated for head lice. Metabolites of the pesticides lindane and permethrin were measured in the samples. RESULTS The mean age of exposed and unexposed children in the study population was 9.3 years and 8.5 years, respectively. Fourteen of the 29 exposed children used prescription lice treatments (i.e., lindane or malathion); 25 of the 29 exposed children used at least one over-the-counter permethrin treatment, either alone or in addition to prescription treatments. Exposed children in both counties had higher urinary pyrethroid metabolite levels in their post-exposure samples compared with their baseline samples. However this difference was only significant in Forsyth County children. CONCLUSIONS The significantly increased post-exposure pyrethroid metabolite levels in the urine of Forsyth County children suggest that the children are exposed to pyrethroid insecticides through the use of lice shampoos.

Use of lead isotope ratios to identify sources of lead exposure in Alaska Natives

OBJECTIVES: Although banned nationwide for waterfowl hunting, lead shot is still used for hunting in regions of Alaska. Consumption of birds hunted with lead shot may be a route of human lead exposure in susceptible populations. The Centers for Disease Control and Prevention (CDC) and Alaskan health officials conducted a cross-sectional exposure assessment and used isotope ratios (IR) to test that assumption. STUDY DESIGN: Cross-sectional exposure assessment study. METHODS: We compared isotopic profiles of blood lead in Alaska Native women from Bethel (n = 10) and Barrow (n = 10) to lead shot samples purchased from the respective regions. To evaluate the source of lead for the buckshot, we evaluated IR profiles for lead mineral and ore from a smelter in Torreon, Mexico, a suspected source of origin for the lead. RESULTS: The lead IRs for the blood lead differed significantly from the lead shot IRs (p > 0.001); thus, lead shot is unlikely to be the sole source of lead exposure of public health significance in participants of this study. Overlap in IRs for the lead shot and blood lead existed for 6 (30%) of the women from Bethel and Barrow; however, no correlation was noted between lead levels and the IRs for the blood lead. IR profiles for lead mineral and ore from Mexico were substantially different from the IRs of lead shot from Alaska, confirming that buckshot in this study is unlikely to originate from the Mexican smelter. CONCLUSIONS: Lead shot from the manufacturer in this study does not appear to be the sole source of lead exposure in most participants; nonetheless, lead shot could yet be a potential source of exposure in some populations, possibly those whose diet consists of game hunted with lead shot.

Operationalizing One Health: Stone Mountain and Beyond

Although the interconnection of humans, animals, and ecosystems has been recognized historically, increasing specialization of professionals in the twentieth century led to decreased communication and collaboration among sectors. In early 2000, a One Health vision of global interconnectedness began gaining in popularity and a series of meetings were held extolling the One Health vision. However, by 2009, detractors were claiming that the One Health approach was indeed all vision and no action. In response to this, international organizations sponsored a carefully planned and structured meeting to construct a way forward that would lead to tangible outcomes. The Stone Mountain meeting, Operationalizing “One Health”: A Policy Perspective—Taking Stock and Shaping an Implementation Roadmap led to the formation of seven multi-national work groups with defined timelines and outputs. The process has garnered increasing participation and support, and the work groups are on track to demonstrate the value added of a One Health approach.