Dietary characterizations in a study of human exposures in the Lower Rio Grande Valley .1. Foods and beverages

The Lower Rio Grande Valley Environmental Study (LRGVES), a cooperative effort between various federal and state agencies, responded to concerns of the local community about possible adverse health effects related to environmental conditions. The LRGVES pilot project, conducted during the spring and summer of 1993, was designed as a range-finding or scoping study to evaluate multiple forms of exposure to nine Valley residents in preparation for possible expanded studies. Potential dietary exposures were characterized by the use of food diaries and questionnaires and the collections and analysis of foods, beverages, and drinking water consumed by the participants. This publication describes the results obtained for foods and beverages. Results for drinking water are described in a companion publication. A duplicate-diet collection procedure was used to obtain food and beverage samples. Participants prepared duplicate portions of solid foods and beverages which were composited separately over a 24-h period. A broad-based analytical approach was taken. The duplicate-diet composites and additional local food items were analyzed for numerous pesticides, industrial chemicals, polycyclic aromatic hydrocarbons (PAHs), toxic and essential elements, natural toxins, and specific nutrients. While it is not possible to quantify long-term exposures from the results observed during two brief sampling periods, many insights were gained regarding the general levels of nutrients and chemical residues in foods and beverages ingested by the Valley population. Of the more than 200 pesticides potentially detectable by the methods used, 38 were found at levels typical of those reported for foods in the U.S. The most common were DDE and other environmentally persistent pesticides and high-use pesticides. None of the residue findings approached USFDA violative levels for individual food items. However, concentration of lindane and dieldrin found in participants' 24-h composite diets exceed the USEPA's health-based standards for long-term exposures, Several other areas were identified that either required intervention to mitigate exposures or the need for further investigation. Concentration of lead in the 24-h diets of many of the participants were above those typically seen in the U.S. Another notable finding far local foods was a high level (399 mg/kg) of polychlorinated biphenyl compounds (PCBs) in a carp caught from a local irrigation canal and intended for consumption. Subsequent sampling confirmed PCB contamination of bottom fish. Several local waters were closed to fishing, Levels of nutrients in 24-h diet composites suggested participants' need to increase their intakes of calories, carbohydrates, and many essential vitamins as well as to reduce intakes of fat and salty food. Published by Elsevier Science Ltd.