Pesticide residues in food: investigation of disparities in cancer risk estimates

A global environmental health perspective and optimisation of stress

The phrase "what doesn't kill us makes us stronger" suggests the possibility that living systems have evolved a spectrum of adaptive mechanisms resulting in a biological stress response strategy that enhances resilience in a targeted quantifiable manner for amplitude and duration. If so, what are its evolutionary foundations and impact on biological diversity? Substantial research demonstrates that numerous agents enhance biological performance and resilience at low doses in a manner described by the hormetic dose response, being inhibitory and/or harmful at higher doses. This Review assesses how environmental changes impact the spectrum and intensity of biological stresses, how they affect health, and how such knowledge may improve strategies in confronting global environmental change.

Tumor promoting and co-carcinogenic effects in medium-term rat hepatocarcinogenesis are not modified by co-administration of 12 pesticides in mixture at acceptable daily intake

The purpose of this investigation was to evaluate the possible influence of a mixture of pesticides on medium-term carcinogenesis using improved hepatocarcinogenesis protocols. We performed a 12 commercially available pesticides combination with alachlor, atrazine, carbofuran, chlorpyrifos, diazinon, dicofol, endosulfan, iprodione, mancozeb, maneb, procymidone and rotenone. The mixture was given at 1-fold and 10-fold the acceptable daily intake (ADI) level in a set of Solt-Farber-derived protocols involving diethylnitrosamine, 2-acetylaminofluorene treatments and a partial hepatectomy. Co-carcinogenic effect and promoting activity were evaluated using gamma-glutamyl transpeptidase (GGT) positive altered hepatocyte foci, as well, protein and mRNA levels of glutathione S-transferase P (GSTP) in liver extracts as molecular biomarkers of carcinogenic effects. The pesticide treatments when compared to vehicle treatments always produced the same number of hepatocyte lesions and an equal GSTP expression on liver extracts independently of carcinogenic-protocol utilized. On this base, we concluded that the pesticide mixture evaluated in this report does not have tumor promoting activity or co-carcinogenic effect in the rat medium-term liver carcinogenesis. Altogether these data contribute to the confidence that the ADI represents a safe intake level to mixture of pesticides at dietary exposure.

Allium cepa chromosome aberration and micronucleus tests applied to study genotoxicity of extracts from pesticide-treated vegetables and grapes

The Allium cepa assay is an efficient test for chemical screening and in situ monitoring for genotoxicity of environmental contaminants. The test has been used widely to study genotoxicity of many pesticides revealing that these compounds can induce chromosomal aberrations in root meristems of A. cepa. Pesticide residues can be present in fruit and vegetables and represent a risk for human health. The mutagenic and carcinogenic action of herbicides, insecticides and fungicides on experimental animals is well known. Several studies have shown that chronic exposure to low levels of pesticides can cause birth defects and that prenatal exposure is associated with carcinogenicity. This study evaluated the potential application of plant genotoxicity tests for monitoring mutagens in edible vegetables. The presence of pesticides and genotoxic compounds extracted from 21 treated vegetables and eight types of grapes sampled from several markets in Campania, a region in Southern Italy, was monitored concurrently. The extracts were analysed for pesticides by gas chromatography and high-performance liquid chromatography, and for genotoxicity using two plant tests: the micronucleus test and the chromosomal aberration test in A. cepa roots. Thirty-three pesticides were detected, some of which are not approved. Genotoxicity was found in some of the vegetables and grapes tested. Allium cepa tests proved to be sensitive in monitoring genotoxicity in food extracts. The micronucleus test in interphase cells gave a much higher mutagenicity than the chromosomal aberration test in anaphase-telophase cells.

Risk assessment through dietary intake of total diet contaminated with pesticide residues in Punjab, India, 1999-2002

Forty-six samples each of vegetarian and nonvegetarian total diet consumed from March 1999 to December 2002 by male subjects in the age group of 19-24 years were analyzed to assess their risk through dietary intake with respect to pesticide residues. The results revealed low dietary intake of levels of Sigma-dichlorodiphenyltrichloroethane (DDT) and which were almost comparable to levels reported in developed countries. The results are indicative of contamination of total diet with pesticide residues despite a ban on the use of DDT and restricted use of lindane in agriculture only. Predominance of lindane residues indicates that liquid milk was a main contributory source as it comprises almost 21% to the total diet consumed per day. Concerted efforts by regulatory authorities and emphasis on judicious use of agrochemicals in pest control are required to decrease the burden of these chemicals in food stuffs to levels safe for dietary intake.

Focused interviews with Sudanese Americans: perceptions about diet, nutrition, and cancer

BACKGROUND

This study explored perceptions regarding diet, nutrition and cancer among Sudanese-Americans; and generated information for response options, components to questions, and actual questions for a pre-conceptualized diet, nutrition and cancer-related questionnaire to be used on this population.

METHODS

In a descriptive, qualitative study, data were collected from four focus group discussions with Sudanese-Americans (N = 18).

RESULTS

Most participants were fearful of cancer, associating it with death. Stress, genetics, and pesticides in vegetables were given as major causes of cancer. Fatalism towards cancer pervaded among a few participants. Male participants did not believe that dietary factors could be helpful in cancer prevention, while the females believed fried, fatty, smoked and fast foods could lead to cancer. Factors perceived as influencing food choices included money, cultural traditions and social class. Cultural tradition was perceived as the major barrier to changing food habits. Frying, stewing, grilling, boiling and fermenting were the most common food preparation methods reported.

CONCLUSION

Perceptions regarding dietary practices, nutrition and cancer among Sudanese-Americans, some of which might have been overlooked were identified. The focus groups generated response options, components to questions, and actual questions for a pre-conceptualized diet, nutrition and cancer-related questionnaire to be used on Sudanese-Americans.

[Remarks of the Zurich Discussion Panel on the gene test]

Leider besteht für diesen Artikel keine Zusammenfassung. Als Einstieg stellen wir den Textanfang zur Verfügung. Seit einiger Zeit wird ein Gentest angeboten, mit dem sich angeblich das individuelle Risiko für z.B. Herz-/Kreislauferkrankungen, Thrombosen, Osteoporose, Mammakarzinom oder Schwangerschaftskomplikationen durch die Analyse von 18 genetischen Parametern bzw. deren Polymorphismen erkennen lässt. Anhand der Ergebnisse dieses Tests soll es dann möglich sein, für jede Frau die optimale Hormonsubstitution festzulegen und die individuellen Krankheitsrisiken durch geeignete Massnahmen zu minimieren. Nach der Veröffentlichung einer kurzen Stellungnahme zu diesem Gentest im Addendum der jüngsten Empfehlungen des Zürcher Gesprächskreises zur Hormonsubstitution in ‘Frauenarzt’ 2/2002 gingen verschiedene Kommentare ein. Der Zürcher Gesprächskreis sieht sich deshalb veranlasst, zum Thema Polymorphismen eine ausführliche Stellungnahme abzugeben.

Risk characterization: principles and practice

In the field of risk assessment, characterizing the nature and magnitude of human health or environmental risks is arguably the most important step in the analytical process. In this step, data on the dose-response relationship of an agent are integrated with estimates of the degree of exposure in a population to characterize the likelihood and severity of risk. Although the purpose of risk characterizations is to make sense of the available data and describe what they mean to a broad audience, this step is often given insufficient attention in health risk evaluations. Too often, characterizations fail to interpret or summarize risk information in a meaningful way, or they present single numerical estimates of risk without an adequate discussion of the uncertainties inherent in key exposure parameters or the dose-response assessment, model assumptions, or analytical limitations. Consequently, many users of risk information have misinterpreted the findings of a risk assessment or have false impressions about the degree of accuracy (or the confidence of the scientist) in reported risk estimates. In this article we collected and integrated the published literature on conducting and reporting risk characterizations to provide a broad, yet comprehensive, analysis of the risk characterization process as practiced in the United States and some other countries. Specifically, the following eight topics are addressed: (1) objective of risk characterization, (2) guidance documents on risk characterization, (3) key components of risk characterizations, (4) toxicity criteria for evaluating health risks, (5) descriptors used to characterize health risks, (6) methods for quantifying human health risks, (7) key uncertainties in risk characterizations, and (8) the risk decision-making process. A brief discussion is also provided on international aspects of risk characterization. A number of examples are presented that illustrate key concepts, and citations are provided for approximately 100 of the most relevant papers.

What do animal cancer tests tell us about human cancer risk?: Overview of analyses of the carcinogenic potency database

Many important issues in carcinogenesis can be addressed using our Carcinogenic Potency Database, which analyzes and standardizes the literature of chronic carcinogenicity tests in laboratory animals. This review is an update and overview of our analyses during the past 15 years, using the current database that includes results of 5152 experiments on 1298 chemicals. We address the following: 1. More than half the 1298 chemicals tested in long-term experiments have been evaluated as carcinogens. We describe this positivity rate for several subsets of the data (including naturally occurring and synthetic chemicals), and we hypothesize and important role in the interpretation of results for increased cell division due to administration of high doses. 2. Methodological issues in the interpretation of animal cancer tests: constraints on the estimation of carcinogenic potency and validity problems associated with using the limited data from bioassays to estimate human risk, reproducibility of results in carcinogenesis bioassays, comparison of lifetable and summary methods of analysis, and summarizing carcinogenic potency when multiple experiments on a chemical are positive. 3. Positivity is compared in bioassays for two closely related species, rats and mice, tested under similar experimental conditions. We assess what information such a comparison can provide about interspecies extrapolation. 4. Rodent carcinogens induce tumors in 35 different target organs. We describe the frequency of chemicals that induce tumors in rats or mice at each target site, and we compare target sites of mutagenic and nonmutagenic rodent carcinogens. 5. A broad perspective on evaluation of possible cancer hazards from rodent carcinogens is given, by ranking 74 human exposures (natural and synthetic) on the HERP indes.