Access to safe drinking water has a direct effect on improving human health and their quality of life. One country still struggling with providing access to safe drinking water to all of its population is Panama. Panama's largest indigenous group, the Ngöbe people, is disproportionately affected by lack of access to safe drinking water. One way Panama's Ministry of Health (MINSA) is attempting to increase access to safe drinking water to the Ngöbe people is by disinfecting the water already captured by rural gravity fed water systems constructed within in the Ngöbe-Bugle reservation. This is accomplished using an in-line chlorinator specifically designed to accommodate locally manufactured calcium hypochlorite tablets as a source of chlorine. However, in this study it was hypothesized that the current way MINSA is implementing the in-line chlorinator was ineffective both at educating communities on knowledge of chlorination and in chlorinating water in their water distribution systems. This study investigated MINSA's implementation method and then compared it to a new method of implementation that was based on a newly developed disinfection field guide created by the author of this thesis. The motivation of this study was to improve this process of implementation which could lead to more effective chlorination thereby decreasing illness caused by waterborne pathogens. Each implementation method investigated attempted to disseminate knowledge of chlorination to community members through a seminar. The MINSA seminar was presented by a MINSA health practitioner and a newly developed seminar was presented by this thesis's author. A survey was developed to assess the knowledge of chlorination of community members after they attended a seminar. Results showed that community members who attended the new seminar on average answered 20 of the 22 questions of the administered survey more correctly than community members attending the MINSA seminar. Additionally, based on the average correct response of community members to survey questions, participants in the new seminar answered more questions correctly compared to participants in the MINSA seminar in all sections of the survey, 32% greater in the "General Knowledge" section; 43% greater in the "MINSA Specific" section; and 36% greater over the total survey. This higher score by new seminar participants suggests that the new seminar is better at educating community members on knowledge of chlorination. An assessment of each implementation method to effectively chlorinate the studied community's water distribution systems was also completed. This was done by measuring the free chlorine residual of water leaving the studied community's storage tank and entering the distribution system over one week. These concentration values were multiplied by a calculated chlorine contact time of the studied system's distribution system to determine Ct values. Measured Ct values were compared to literature guidelines that provide information on what Ct values will kill commonly found waterborne pathogens in the region. Calculated Ct values above a critical literature value of 40.0 min-mg/L Cl2 were determined to be effectively chlorinating a system's water. Results showed that when using the MINSA implementation method the required Ct level of 40.0 min-mg/L Cl2 was never met at any time during the week. However when using the new implementation method, the required Ct level of 40.0 min-mg/L Cl2 was met at all points during the week except one when tested on the last day where the Ct value was found to be 35.9 min-mg/L Cl2. These results suggest the new implementation method is more effective at chlorinating rural gravity fed water systems in the region compared to the previous implementation method.

In 2014, the global pesticide industry's projected worth is $52 billion and by 2020, the developing world will make up one-third of the world's chemical production and consumption. Pesticides can have unintended negative consequences for human health and the environment, especially in the developing world where regulations are loose or nonexistent. One country with unrestricted use of pesticides is Panam[aacute], especially in Santa Rosa de Cucunatí. In this indigenous village, small-scale farmers and ranchers spray paraquat, glyphosate, picloram, and 2,4-D at higher elevations than the spring water source of a gravity-fed water system, the river, and the village. The objective of this study was to estimate the concentration of these pesticides in the water system and the river and to perform a human health and ecological risk assessment. Pesticide fate and transport models in the graphical user interface EXAMS-PRZMS Exposure Simulation Shell (EXPRESS), which was developed by the United States Environmental Protection Agency, were used to predict concentrations of the four mentioned pesticides in drinking water and the river using chemical properties, data from Food and Agriculture Organization and Smithsonian Tropical Research Institute, and the author's experience as a Peace Corps Volunteer. The results from Tier I model FQPA Index Reservoir Screening Tool (FIRST) were used to compare immediate and delayed rain events, noting minimal difference. The Tier II PRZM-EXAMS shell provided estimated drinking water concentration (EDWC) profiles. The paraquat profile was much lower than picloram, glyphosate, and 2,4-D, which had almost identical profiles with peak concentrations around 12 ppm and the average annual concentration 100 ppb. Average Daily Dose (ADD) via drinking water was calculated for men, women, and children using model results and compared to the oral reference dose (RfD). ADDs only exceeded the RfD with maximum peak EDWCs, implying low risk. However, RfD was used to calculate a breakpoint concentration, the concentration at which each pesticide presents a risk to the consumer. This was then compared to the maximum peak (highest, i.e. worst-case scenario) and annual (lowest, i.e. best-case scenario) EDWC profiles. In the best-case scenario, glyphosate and picloram did not pose a threat, paraquat posed a moderate threat and 2,4-D posed a high threat, with the concentration exceeding the breakpoint for 90 percent of the years. With respect to the worst-case scenario, all four chemicals posed high threats to the consumer. Individual exposure via consumption of fish from the river was calculated using a calculated bioconcentration (BCF) factor and calculated breakpoint concentrations. For the best case scenario, picloram presented a low risk and 2,4-D presented a high risk but for the worst case, both of these chemicals presented a very high risk. An additive exposure of these two human health pathways found that for the best case scenario, exposure from most of the four chemicals did not approach the RfD. However, for the worst-case scenario the exposures were significantly higher than the oral RfD--therefore, between the lowest and the highest concentrations, the general population is at risk. For the ecological risk assessment, the 96-hour peak profile was compared to the 96-hour lethal dose (LD50); glyphosate posed a high risk to fathead minnows and low risk to bluegills and 2,4-D presented a high risk to fathead minnows, low risk to channel catfish, and very high risk to bluegills. A more general risk assessment compared maximum peak and annual concentrations to the US EPA's aquatic life benchmarks. Glyphosate presented no threat and 2,4-D only presented a threat to plants. For picloram, fish were at very high risk at the chronic level and low risk at the acute level, and plants were at moderate risk. Paraquat presented the most significant threat to aquatic life, exceeding benchmarks for all plants and invertebrates at the chronic level 100 percent of the time. It presented no threat to fish in the best-case scenario, but a high risk for fish at the chronic level in the worst case scenario, as well as very high risk for all invertebrates and plants. Improvements in application and watershed protection as part of a multi-disciplinary approach are proposed in place of technological mitigation strategies. Recommendations for future studies include the development of a developing-world context model and experimental studies in the developing world to compare to model results, where possible.