ABSTRACT
Limited supply of clean water in urbanizing watersheds creates challenges for safely sustaining irrigated agriculture and global food security. On-farm interventions, such as riverbank filtration (RBF), are used in developing countries to treat irrigation water from rivers with extensive fecal contamination. Using a Bayesian approach incorporating ethnographic data and pathogen measurements, quantitative microbial risk assessment (QMRA) methods were employed to assess the impact of RBF on consumer health burdens for Giardia, Cryptosporidium, rotavirus, norovirus, and adenovirus infections resulting from indirect wastewater reuse, with lettuce irrigation in Bolivia as a model system. Concentrations of the microbial source tracking markers pepper mild mottle virus and HF183 Bacteroides were respectively 2.9 and 5.5 log10 units lower in RBF-treated water than in the river water. Consumption of lettuce irrigated with river water caused an estimated median health burden that represents 37% of Bolivia's overall diarrheal disease burden, but RBF resulted in an estimated health burden that is only 1.1% of this overall diarrheal disease burden. Variability and uncertainty associated with environmental and cultural factors affecting exposure correlated more with QMRA-predicted health outcomes than factors related to disease vulnerability. Policies governing simple on-farm interventions like RBF can be intermediary solutions for communities in urbanizing watersheds that currently lack wastewater treatment.
Subject(s)
Bayes Theorem , Wastewater/virology , Agricultural Irrigation , Giardia , Humans , Norovirus , Risk AssessmentABSTRACT
Viable ova of Ascaris lumbricoides, an indicator organism for pathogens, are frequently found in feces-derived compost produced from ecological toilets, demonstrating that threshold levels of time, temperature, pH, and moisture content for pathogen inactivation are not routinely met. Previous studies have determined that NH(3) has ovicidal properties for pathogens, including Ascaris ova. This research attempted to achieve Ascaris inactivation via NH(3) under environmental conditions commonly found in ecological toilets and using materials universally available in an ecological sanitation setting, including compost (feces and sawdust), urine, and ash. Compost mixed with stored urine and ash produced the most rapid inactivation, with significant inactivation observed after 2 weeks and with a time to 99% ovum inactivation (T(99)) of 8 weeks. Compost mixed with fresh urine and ash achieved a T(99) of 15 weeks, after a 4-week lag phase. Both matrices had relatively high total-ammonia concentrations and pH values of >9.24 (pK(a) of ammonia). In compost mixed with ash only, and in compost mixed with fresh urine only, inactivation was observed after an 11-week lag phase. These matrices contained NH(3) concentrations of 164 to 173 and 102 to 277 mg/liter, respectively, when inactivation occurred, which was below the previously hypothesized threshold for inactivation (280 mg/liter), suggesting that a lower threshold NH(3) concentration may be possible with a longer contact time. Other significant results include the hydrolysis of urea to ammonia between pH values of 10.4 and 11.6, above the literature threshold pH of 10.
Subject(s)
Ammonia/toxicity , Ascaris/physiology , Feces/parasitology , Ovum/drug effects , Sanitary Engineering/methods , Animals , Ascaris/drug effects , Bolivia , Feces/chemistry , Humans , Linear Models , Time Factors , Toilet Facilities , Urine/chemistryABSTRACT
El informe final presentado por el representante de Bolivia al curso regional describe las actividades de el Centro de Aguas y Saneamiento Ambiental (CASA), institucion a la que pertence, en temas como: muestreo de aguas superficiales y suterráneas, muestreo de sitios contaminados, tratrabilidad de aguas residuales y modelación
Subject(s)
Water Purification , Sampling Studies , Surface Waters , Groundwater , Bolivia , BoliviaABSTRACT
En el informe de país elaborado por el representante de Bolivia al curso regional presenta las características ambientales de su país, detallando las cuencas hídricas existentes y la calidad de la mismas. Informa tambien sobre la contaminación tanto en aguas superficiales y subterráneas producida por mercurio, plaguicidas, fertilizantes e hidrocarburos, debido a las actividades industriales, mineras, agrícolas y a la disposición de residuos líquidos domésticos. Por último explica la misión y las actividades realizadas por el Centro de Aguas y Saneamiento Ambiental
Subject(s)
Water Resources , Water Quality , Water Pollution , Bolivia , BoliviaABSTRACT
En el informe de país elaborado por el representante de Bolivia al curso regional presenta las características ambientales de su país, detallando las cuencas hídricas existentes y la calidad de la mismas. Informa tambien sobre la contaminación tanto en aguas superficiales y subterráneas producida por mercurio, plaguicidas, fertilizantes e hidrocarburos, debido a las actividades industriales, mineras, agrícolas y a la disposición de residuos líquidos domésticos. Por último explica la misión y las actividades realizadas por el Centro de Aguas y Saneamiento Ambiental
Subject(s)
Bolivia , Water Pollution , Water Quality , Water Resources , BoliviaABSTRACT
El informe final presentado por el representante de Bolivia al curso regional describe las actividades de el Centro de Aguas y Saneamiento Ambiental (CASA), institucion a la que pertence, en temas como: muestreo de aguas superficiales y suterráneas, muestreo de sitios contaminados, tratrabilidad de aguas residuales y modelación
