GRIC Environmental Health Service staff members developed a questionnaire and identified agricultural employers whose workers would participate in the interview. The questionnaire was designed to characterize workers at GRIC and included questions about occupational injuries and illnesses.

Investigators gathered information from medical records for past injuries and illnesses related to farming, worker compensation claims and records of accident and injury investigations, and developed an agriculture injury and illness tracking database. Data collection was completed in July and will be evaluated by a qualified statistician. An analysis team will then study the data and release information concerning injury and illness trends to help identify hazards.

The information will be posted on a Web site created on the tribes' intranet to aid in the process of developing community health and safety priorities and interventions, including education, training programs, monitoring and promotion of targeted health services.

For more information about the Gila River Indian Community project, please call Eric Faisst at (602) 528-1226, extension 1089, or e-mail efaisst@gilanet.net.

These chemicals persist longer indoors than in agricultural environments due to diminished or filtered sunlight, reduced moisture and air movement, surface area and lack of soil microorganisms. Measurable dermal, oral and inhalation exposure occurs over a period of weeks to months. However, when used as directed, the systemic exposure levels of household pesticides are well below toxic thresholds based upon the normal experience of consu-mers, and measured dosages of residents are well below toxic levels, according to Robert Krieger, Ph.D., extension toxicologist who directs the Personal Chemical Exposure Program, Department of Entomology at UC Riverside.

Krieger presented "Models and Measures of the Pesticide Exposures in Californians" during the UC Ag Health and Safety Center's May 4 noon seminar. His research involving household and agricultural worker exposure to pesticides has appeared in various publications, including those of the American Chemical Society and the British Occupational Hygiene Society. An important generalization resulting from the studies was that measured aggregate pesticide exposures are substantially less and more persistent than pesticide exposure estimates resulting from default models.

During his noon seminar talk at the Ag Health and Safety Center, Krieger discussed a revealing study conducted with his colleagues at UC Riverside investigating the effects of insecticide use in residences. Researchers monitored human chlorpyrifos exposures following three different types of household pesticide applications--fogger, broadcast and crack-and-crevice. Their initial studies included two successive fogger appli-cations in a 2,000-sq.ft. residence approximately a year apart. Both studies were conducted by biomonitoring a family of eight in Highland, near San Bernardino, Calif. Flea and roach foggers were discharged into six primary unobstructed areas, and the home was ventilated after two hours. The occupants re-entered later in the day.

The researchers performed three post-application situational monitoring studies based upon the interest and cooperation of family members, friends and acquaintances who were familiar with previous exposure studies. Homes were treated by the residents themselves as part of normal pest management activities. The "Poly Fogger" study was conducted by biomonitoring a family of four residing in an 1,800-sq. ft. nylon-carpeted home in Riverside, Calif. The broadcast (indoor and outdoor insect control) situational monitoring of a family of five in Riverside was conducted following treatment of the residence with a broadcast application of diluted aqueous suspension of Spectracide Dursban indoor and outdoor insect control for houseflies and unspecified nuisance insects.

The crack-and-crevice study was conducted by biomonitoring a family of five living in Corona, Calif., that had contracted with a certified pesticide applicator to apply a diluted aqueous suspension of Dursban Pro.

Study results revealed persistence of total residue on carpet that was substantially greater than the persistence of transferable residue. Urine samples showed low-level exposures of family members that lasted for periods of weeks to a month after pesticide use. Children eliminated more trichloro-2-pyridinol (TCP) biomarker than their parents on a kg/body weight/day basis, measured through spot urine specimens corrected for volume by an age-specific creatinine correction.

"Environmental residues may become useful elements of predictive residential exposure models," says Krieger, "but their potential contribution to indirect exposure assessments must include careful determination of residue availability for contact transfer to clothing or skin."

Krieger used environmental data from this study to estimate residential exposure according to established residential exposure assessment standard operating procedures, and found measured exposures to be substantially less than default model estimates assessments. Therefore, experimental and situational monitoring of exposed persons are valuable for meaningful and responsible predictive pesticide exposure model building.

In other studies conducted in 1995 and 1997 involving malathion exposures of strawberry harvesters in Watsonville, Calif., Krieger and his colleagues monitored the mono- and diacids of malathion in urine specimens of workers. Dermal pesticide exposure through hand absorption is well known, but the estimation of the quantitative contribution of hand contact to absorbed dose had been very poorly studied. Krieger reported an almost 50 percent reduction in dermally absorbed malathion in harvesters who used rubber latex gloves, compared to dermal pesticide absorption by bare-handed workers in the same fields. An isopropanol rinse removed about three to 10 times more malathion from workers' gloves than was absorbed by ungloved workers. This finding provides direct evidence of the contribution of hands to absorbed dose. The high pesticide levels recovered from glove rinses make gloves an unreliable dosimeter under most conditions. This finding is not general and requires further study.

Risk reduction in the use of pesticides is an important objective that is defined differently by regulators, manufacturers, product representatives, pest control advisers and operators, pesticide handlers, retailers, consumers and their advocates, and politicians. Usually the issue is exposure rather than the likelihood that a harmful effect will occur. Common exposure reduction strategies include engineering controls, substitution of less toxic products, personal protective equipment, behavioral modification, regulatory and institutional responses, and protective clothing. By developing more accurate personal chemical exposure data, the risk of exposure to chemicals used as pesticides can be reduced. Without modifying pesticide use practices or using "safer" pesticides, more accurate human exposure data can result in risk assessments that are less reliant upon uncertainty and default assumptions that inflate exposure assessments and may misguide development of mitigation measures and people's perception of their well being.

Zoonoses (pronounced zo-eh-NO-sis) are defined as diseases communicable from animals to humans under natural condi-tions. Each year commercial airlines attract 1.5 billion passengers, many of whom travel on international flights. Consequently, a person who is incubating an infectious disease from Africa, for example, can carry that disease into the United States in a day's time. Additionally, a marked increase in worldwide trade augments the opportunity for pathogens to enter our markets through food products and importation of exotic pets.

Chomel presented "Emerging Bacterial Zoonoses" to a group of individuals attending the Center's noon seminar on June 1. "In 1998 an estimated 54 million people worldwide died. Of those deaths, at least 25 percent were caused by infectious diseases," reported Chomel. "Respiratory, viral, tuberculosis and zoonotic infestations are some of the major diseases in humans, and because of advanced technology and economic changes, we are seeing an emergence worldwide of new pathogens and new diseases."

Of the estimated 1,700 organisms that have been identified by scientists as human pathogens, approximately 800 are zoonotic agents. In his talk, Chomel identified the following emerging bacterial zoonoses, which he grouped into two principal categories-food-borne and vector- or insect-born origin. Food-borne pathogens:

"Another important factor leading to the emergence of bacterial zoonoses is our kindness for all creatures on this planet," said Chomel. "In 1996, Miami imported 7,000 mammals (of which 1,000 were rodents). We also imported almost 1 million Iguanas and other various lizards."

The popularity of Iguanas and other pet reptiles has raised the number of salmonella cases in the United States. "We know that 94 to 95 percent of reptiles harbor salmonella in their digestive tracts," said Chomel. "The big problem is that salmonella causes serious illness and death in children and toddlers who come into contact with the pathogen." Chomel cited one tragic death involving a toddler who contracted salmonella after sucking on the finger of his father, who had been petting the family's Iguana. Another reported death of a child involved an individual who placed an Iguana in the bathtub while cleaning its cage and later bathed the children in the contaminated bathtub.

The breakdown of public health measures is also associated with the emergence of infectious diseases. "In the United States, the West Nile disease outbreak was a major warning of the fact that we didn't have good mosquito control in a lot of states, particularly in the eastern part of the country," said Chomel.

New bacterial zoonoses are likely to be identified in the near future with the use of new molecular tools, explained Chomel. Pets are the main source for human infection, and most of these diseases can be easily prevented with good hygiene and common sense.