Project 1-358 Bolivia

Partnerships for enhanced engagement in research (PEER) SCIENCE
Cycle 1 (2011 Deadline)

The fate of enteric pathogens in fluids, fields, and food products: on-farm solutions for the safe reclimation of water and nutrients from sewage

PI: Maria de la Mercedes Iriarte Puña, Center for Water and Environmental Sanitation, Universidad Mayor de San Simon (UMSS)

US Partner: James Mihelcic, University of South Florida (USF)

Project Dates: May 2012 - December 2013

Project Overview

Domestic sewage constitutes an important source of water and nutrients for agriculture, especially for water-scarce regions such as Cochabamba, Bolivia, where it is used to irrigate more than 2,000 hectares of crop fields. However, this wastewater contains high concentrations of enteric pathogens, which present serious public health risks to farmers, their families, and consumers of crops. In order to protect public health, effective measures must be taken to reduce exposure to these pathogens. Current policy regulates the quality of wastewater as it leaves the municipal treatment plant. However, the reduction of pathogens can also occur after the treatment plant and on the farm, with engineered social and ecological buffers and health protection measures such as on-farm water storage, indigenous farming techniques, strategic irrigation, and crop-washing. The incorporation of these additional measures extends the limits of conventional wastewater treatment to include stakeholders such as farmers and consumers, effectively making sanitation a more community-managed process.

Taking crop and water samples along the Rocha River, where
some farmers irrigate lettuce and onions indirectly with untreated wastewater

Microscopic observation of parasites from the effluence
from the Rocha River samples

This project looks to measure concentrations of human pathogens in water, soil, and crop samples from six community farms where wastewater is used for irrigation. It will also quantify the differences in pathogen concentrations in the presence and absence of on-farm health protection measures. Specifically, these researchers will measure the specific human pathogens that are responsible for emerging and endemic infectious diseases such as cryptosporidiosis, giardiasis, and helminthiasis. The sampling plan has been designed to measure the effects of different on-farm storage methods, irrigation techniques, and crop washing practices on the survival of pathogens. They will also measure the correlation of the presence of pathogens with traditional water quality indicators such as Escherichia coli. The Center for Water and Environmental Sanitation has developed expertise in laboratory methodologies to detect the above-mentioned pathogens in environmental samples. Their role in this project will be to lead the laboratory analysis component and to provide graduate students who will assist in data collection and field sampling. The U.S. collaborating partner at USF will assist with the design of data collection and sampling techniques in the field. USF graduate students will also collaborate academically with their Bolivian counterparts to collectively publish material and disseminate the results of this study to a broader global audience.

Summary of Recent Activities

Results from sampling efforts in late 2012 indicated the clear impact that the activities of wastewater management system stakeholders on the quality of wastewater used for irrigation. As a follow-up in January 2013, Dr. Iriarte and her students evaluated the condition of a water treatment plant in Arani that is managed by the local farmers who use the water for irrigation. The report on this evaluation, including recommendations on future strategies for operations and maintenance, is being made available to the local community. Another activity undertaken this past quarter was a survey documenting flow rates and source point contamination in the Rocha River. In March, another survey was carried out to document the types of crops being irrigated with wastewater in Arani and Punata. Fortunately, the researchers found that none of the crops being grown this way in the two areas are generally eaten raw. Therefore, it was decided to eliminate crop sampling in these areas to focus on collections of water and soil samples, with crop samples to be taken only along the Rocha River, where farmers are irrigating lettuce and onions indirectly with untreated wastewater. USF PhD student Matthew Verbyla visited Cochabamba in late March and took part in the Rocha sampling efforts.

At the request of Dr. Iriarte, a no-cost extension was recently made on this grant through December 31, 2013, to allow seven additional months to complete the project. Some delays were encountered in acquiring certain test kits and lab reagents that were unavailable in Bolivia and had to be bought from the United States. In addition, due to various reasons, Dr. Iriarte and her team switched some test sites in the lower Cochabamba valley. Instead of focusing on previously selected sites, they will collect samples at two new sites in irrigation areas downstream from Sacaba where the community leadership is more supportive in allowing the researchers access to water sources and fields. Now that the grant extension is in place, Dr. Iriarte will undertake two more sampling campaigns to Arani and Punata and two more to the Rocha River sites. In June 2013 Matthew Verbyla will make a return visit along with U.S. partner Dr. James Mihelcic. Besides meetings and manuscript drafting sessions with the UMSS partners, a highlight of the visit will be the presentation of a short course on integrated wastewater management to be led by Dr. Mihelcic’s colleague Dr. Stewart Oakley. In August or September outreach seminars will be held at each project site (Rocha River, Arani, and Punata) aimed at sharing results of the project with community members and allowing them to ask questions about the meaning of the results.

Sampling point 1, at the entrance of the Arani Wastewater
Treatment Plant, photo courtesy of Dr. Iriarte.

Sampling point 3, effluent of the Punata Wastewater
Treatment Plant, photo courtesy of Dr. Iriarte.