- Methodologies, models, and materials for predictable
removal of pathogens from stormwater during distributed
This project aims to design a bioinfiltration system for removal of
pathogens from stormwater.
To achieve this objective, experiments are conducted in laboratory and
field (1) to identify the key processes that remove or remobilize
bioinfiltration system during stormwater infiltration, (2) to test the
pathogen removal capacity of geomedia such as biochar and iron filings
environmentally relevant conditions,
and (3) to develop model that predict the removal pathogens under intermittent infiltration of stormwater.
- Factors affecting bacterial persistence in water exposed
The project aims to determine the effects of water and bacterial
characteristics on the persistence of bacteria in sunlit ocean waters.
This knowledge is being used to create models of bacterial
Current work uses Staphylococcus aureus and Enterococcus faecalis as
Past work has focused on all types of enteric bacteria. We are using
transcriptomics to better
understand bacterial stress response to photo-stress.
- Through-beach transport of fecal indicator bacteria (FIB). This project focuses on understanding a process by which FIB attached to beach sands can be washed from the sands and potentially enter the coastal ocean via through-beach transport. The project employs a combination of field studies at a beach in Monterey, CA and laboratory based column experiments coupled with computer modeling to understand the detachment and transport kinetics of FIB during this process. This project exclusively used beach sands naturally contaminated with FIB and focused on the mobilization and transport of those FIB under transient saturated-unsaturated conditions typically observed in sands at the land-sea interface.
- Predictive models of beach water quality for the California coast.
This project uses statistical and data-driven models to predict beach
water quality along the California coastline. The study aims at
developing an early warning system of beach pollution to assist
beach management and protect public health. The work is in
Heal the Bay and produces daily Nowcasts for 5
beaches in southern California. The Nowcast system is being
expanded to 20 beaches over the next 3 years.
- Using next-generation sequencing to investigate factors
influencing changes in microbial communities along the
We are working with colleagues to explore how sea spray interacts with
sand to transport microorganisms between the sand and the sea.
- Monitoring the marine environment with environmental DNA
(eDNA) - Obtaining a census of marine life is important to
understand changes in marine ecosystems that result from stressors
such as overfishing, ocean acidification, hypoxia, pollution, and
biological invasions. Traditional monitoring of marine fish and
invertebrate biodiversity and resources is largely dependent on
capture or observational methods, which are often destructive,
invasive, expensive and time-consuming. Marine organisms are
constantly shedding tissue cells and waste into water; these contain
the organisms’ unique DNA signatures. By sequencing environmental
DNA (eDNA) or by detecting species-specific eDNA sequences through
quantitative PCR in marine waters, we believe that we can obtain a
census of marine life present in the water mass. The goal of the
proposed work is to explore the feasibility of using the sequences
of eDNA in marine waters to characterize the distribution,
diversity, and abundance of the organisms present.
- Environmental detection and health risks of enteric pathogens in low-income communities
We are continually undertaking work to investigate the occurrence of
pathogens in water, in the environment, and on hands of individuals in
developing countries. We are interested in their sources, fate, and
transport, and the implications of their presence on health
risk. Current projects are focused on Bangladesh. Previous work was
carried out in Kenya and in Tanzania, as well as Papua New Guinea.
- Quantitative microbial risk assessment
We use QMRA to investigate various microbial pollution scenarios to
better understand how hazards might give rise to illness. We are
particularly interested in using QMRA to set health-based risk thresholds
for microbial source tracking molecular markers.
- Citizen science and coastal water quality
We are collaborating with a social scientist to better understand the attributes of good citizen scientists. This project involves human subjects and field work along the California coast.
- Environmental detection of soil-transmitted helminths in rural Kenya
We have developed a new method to detect soil-transmitted helminth eggs in soil. We are currently using this method to assess the impact of a sanitation intervention on contamination of household soil with soil-transmitted helminth eggs. We are also interested in exploring soil consumption (or geophagy) as a transmission pathway for soil-transmitted helminth infection in young children.