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Ingestion of soil and dust is a pathway of children's exposure to several environmental contaminants, including lead, pesticides, and fecal contamination. Empirically based estimates of central tendency for soil consumption by children in high-income countries range from 9 to 135 dry mg/day. Using a Monte Carlo simulation, we modeled the mass of soil directly and indirectly ingested per day by rural Bangladeshi children and identified the parameters that influence the mass ingested. We combined data from observations of direct and indirect ingestion among children with measurements of soil mass on the children's hands, mother's hands, and objects to quantify soil ingestion/day. Estimated geometric mean soil ingestion was 162 dry mg/day for children 3-5 months, 224 dry mg/day for children 6-11 months, 234 dry mg/day for children 12-23 months, 168 dry mg/day for children 24-35 months, and 178 dry mg/day for children 36-47 months old. Across all age groups, children placing their hands in their mouths accounted for 46-78% of total ingestion and mouthing objects contributed 8-12%. Direct ingestion of soil accounted for nearly 40% of soil ingested among children 6-23 months old. Sensitivity analyses identified that the parameters most affecting the estimates were the load of soil on the child's hand, the frequency of hand-to-mouth contacts while not eating, and, for children 6-23 months old, the frequency of direct soil ingestion. In a rural, low-income setting, children's soil consumption was substantially more than the estimates for children in high-income countries. Further characterizing soil ingestion of children in low-income contexts would improve assessments of the risks they face from soil-associated contaminants.

Agricultural pesticide use is the highest of any industry, yet there is little research evaluating farmworkers' understandings of the health risks chemical exposure poses. This study examines pesticide education, risk perception, and self-protective behaviors among farmworkers in California's Salinas Valley. Fifty current and former farmworkers were interviewed for this research. Despite several potential barriers to risk communication (e.g., language differences and nonuniform methods of pesticide safety training), the respondents understood many of the potential health consequences of exposure while holding elevated levels of risk perception relative to the general public. They received information on the health effects of pesticide exposure from both grower-based training and personal social networks; however, the respondents continued to participate in unnecessarily risky behaviors. (Contains 3 tables and 2 notes.)

Agricultural pesticide use is the highest of any industry, yet there is little research evaluating farmworkers' understandings of the health risks chemical exposure poses. This study examines pesticide education, risk perception, and self-protective behaviors among farmworkers in California's Salinas Valley. Fifty current and former farmworkers were interviewed for this research. Despite several potential barriers to risk communication (e.g., language differences and nonuniform methods of pesticide safety training), the respondents understood many of the potential health consequences of exposure while holding elevated levels of risk perception relative to the general public. They received information on the health effects of pesticide exposure from both grower-based training and personal social networks; however, the respondents continued to participate in unnecessarily risky behaviors. Keywords: farmworkers; pesticides; risk perception; risk communication; self-protective behaviors

The Food Quality Protection Act of 1996 recognizes that dermal exposure plays a crucial part in the total well-being of individuals. The law requires the Environmental Protection Agency to consider total exposure, including dermal exposure, to obtaoin a complete human health risk model. Dermal route research, however, have largely focused on dermal dose or the uptake or absorption of a chemical through the skin.

The environmental impacts of gas and leachate formation mechanisms in landfills and appropriate control measures to eliminate or minimize these impacts were presented. Gas and leachate migration from landfill boundaries and their release to the environment create serious environmental concerns such as potential health hazards, fires and explosions, damage to vegetation, and global warming. Installation of gas recovery, collection and treatment system and hydraulic barriers were found to help control gas and leachate problems, respectively.

The liquid scintillation energy spectra from the analysis of the radioisotope 232U were obtained for ranges of pH and NaCl concentration, using a variety of scintillation cocktails. Shifts in peak position, as well as variation in peak widths and total counts, were observed for the variables studied. The results suggest that 232U, a narrow energy band [Alpha]-particle emitter, can be analyzed with an energy window significantly more narrow than the instrument full scale. This results in the elimination of much of the incidental background counts associated with additive instrument detection errors in the high-energy region, as well as [Alpha]- and [Beta]-activity of daughter products.

The transport of cadmium and selenite in porous and alumina particles with different particle size was studied. Experiments were performed wherein the rates of cadmium and selenite uptakeof three transition aluminas were measured. The measured values were further analyzed by means of a rate diffusion model. Results indicate that the uptake behavior of the transition aluminas are influenced by their physical and chemical characteristics, such as pore structure, particle size and crystal structure.

Equilibrium surface reactions in selenite were analyzed to gain an insight into the kinetic processes during oxidation. The results showed that selenite is oxidized as a charged surface-adsorbed species and that selenate does not have an adverse effect on surface quality. Oxygen is reduced as a neutral surface-adsorbed species and the rate of oxidation is not a simple function of pH.