Community health workers (promotores de salud) have the ability to empower communities to mitigate negative health outcomes. Current training efforts in environmental topics are lacking. This project addressed this gap by developing 4 transferable training modules on environmental health. By applying a series of surveys, interviews, and trainings, we evaluated their relevance. Partners provided favorable feedback for 3 of the 4 modules. It was also learned that the development method could be improved by engaging technically trained promotores de salud in the role of co-creators. This project has implications for environmental justice communities as it can lessen information disparities.
PMID: 11764852;Abstract:
Development of environmentally benign approaches to remediation of metal-contaminated soils and sewage sludges are needed to replace currently used techniques of either landfilling or metal extraction using caustic or toxic agents. We report results from four application technologies that use a metal-chelating biosurfactant, rhamnolipid, for removal of metals or metal-associated toxicity from metal-contaminated waste. The four applications include: 1) removal of metals from sewage sludge; 2) removal of metals from historically contaminated soils; 3) combined biosurfactant/phytoremediation of metal-contaminated soil; and 4) use of biosurfactant to facilitate biodegradation of the organic component of a metal-organic co-contaminated soil (in this case the biosurfactant reduces metal toxicity). These four technologies are nondestructive options for situations where the final goal is the removal of bioavailable and leachable metal contamination while maintaining a healthy ecosystem. Some of the approaches outlined may require multiple treatments or long treatment times which must be acceptable to site land-use plans and to the stakeholders involved. However, the end-product is a soil, sediment, or sludge available for a broad range of land use applications.
PMID: 12676702;PMCID: PMC154800;Abstract:
One limitation of employing lux bioreporters to monitor in situ microbial gene expression in dynamic, lab. oratory-scale systems is the confounding variability in the luminescent responses. For example, despite careful control of oxygen tension, growth stage, and cell number, luminescence from Pseudomonas putida RB1353, a naphthalene-degrading lux bioreporter, varied by more than sevenfold during saturated flow column experiments in our laboratory. Therefore, this study was conducted to determine what additional factors influence the luminescent response. Specifically, this study investigated the impact of temperature, pH, and initial cell number (variations within an order of magnitude) on the peak luminescence of P. putida RB1353 and the maximum degradation rate (Vmax) during salicylate and naphthalene catabolism. Statistical analyses based on general linear models indicated that under constant oxygen tension, temperature and pH accounted for 98.1% of the variability in luminescence during salicylate catabolism and 94.2 and 49.5% of the variability in Vmax during salicylate and naphthalene catabolism, respectively. Temperature, pH, and initial substrate concentration accounted for 99.9% of the variability in luminescence during naphthalene catabolism. Initial cell number, within an order of magnitude, did not have a significant influence on either peak luminescence or Vmax during salicylate and naphthalene catabolism. Over the ranges of temperature and pH evaluated, peak luminescence varied by more than 4 orders of magnitude. The minimum parameter deviation required to alter lux gene expression during salicylate and naphthalene catabolism was a change in temperature of 1°C, a change in pH of 0.2, or a change in initial cell number of 1 order of magnitude. Results from this study indicate that there is a need for careful characterization of the impact of environmental conditions on both the expression of the reporter and catabolic genes and the activities of the gene products. For example, even though lux gene expression was occurring at ∼35°C, the luciferase enzyme was inactive. Furthermore, this study demonstrates that with careful characterization and standardization of measurement conditions, the attainment of a reproducible luminescent response and an understanding of the response are feasible.
PMID: 12727237;Abstract:
Electric fields and currents have been shown to be capable of disinfecting drinking water and reducing the numbers of bacteria and yeast in food. However, little research has been conducted regarding the effectiveness of electric fields and currents in the inactivation of viruses. The objective of this study was to compare the ability of bacteria and bacteriophage to survive exposure to direct electric current in an electrochemical cell, where they would be subject to irreversible membrane permeabilization processes, direct oxidation of cellular/viral constituents by electric current, and disinfection by electrochemically generated oxidants. Suspensions of the bacteria Escherichia coli and Pseudomonas aeruginosa and bacteriophage MS2 and PRD1 at both high (approximately 1×106CFU or PFU/mL) and low (approximately 1×103CFU or PFU/mL) population densities were exposed to currents ranging from 25 to 350mA in 5s pulses. Post-exposure plaque counts of the bacteriophage were proportionally higher than bacterial culturable counts at corresponding current exposures. E. coli and MS2 were then exposed to 5mA for 20min at both high and low population densities. The inactivation rate of E. coli was 2.1-4.3 times greater than that of MS2. Both bacteria and bacteriophage were more resistant to exposure to direct current at higher population densities. Also, amelioration of inactivation within the electrochemical cell by the reducing agent glutathione indicates the major mechanism of inactivation in the electrochemical cell is disinfection by electrochemically generated oxidants. The implications of these results are that technologies relying upon direct current to reduce the numbers of microbes in food and water may not be sufficient to reduce the numbers of potentially pathogenic viruses and ensure the safety of the treated food or water. © 2003 Elsevier Science Ltd. All rights reserved.
