As we approach the summer beach season, you may sometimes find a “sightseeing” sign indicating that the area is closed. If fecal pollution is suspected, public health officials can perform lab tests on water samples to see if it is safe or not for people to swim in the water.
Although lab methods are available for health officials, the results are not consistent. To help solve this problem, the National Institute of Standards and Technology (NIST) has teamed up with the Environmental Protection Agency (EPA) to develop a reference – known as SRM 2917 Plasmid DNA for EPA- Developed Fecal Indicators – to help ensure accuracy. results in the course for the methods that health officials use.
“The key objectives for the development of NIST SRM 2917 are to help compare the use of inter -ground water quality monitoring methods and the development of a tool. it can be used to establish performance metrics, ”said EPA research geneticist Orin Shanks, who created it. in the development of SRM with NIST researchers. “SRM can also help scientists, administrators and the public evaluate the quality of measurements.”
The EPA is responsible for developing equipment to monitor the quality of freshwater, including beaches, lakes and rivers used for fishing, canoeing, swimming, surfing and with other reasons. Pollution of these waters due to faulty septic systems, leaky lines, sewage discharges, agricultural runoff, leaks from combined systems, wildlife or other improper disposal of animal waste, and misconduct, Shanks said.
People who have been exposed to fecal contamination, whether through the skin or eating water, can get anything from minor illnesses to life -threatening illnesses. Children, the elderly and people with immune systems can be at risk.
Designed to help reduce this problem, NIST SRM 2917 has 13 genetic markers – known as DNA sequences – that can be used to identify a contaminant source or to predict migration. of fecal pollution for example. The SRM is constructed from a plasmid, a small round DNA molecule found in bacteria and other organisms.
The EPA selected genetic markers of SRM, some of which relied on a decade of group research. Genetic markers in plasmid DNA are signs of fecal pollution. “Fecal markers are targets such as bacteria or genetic markers that indicate fecal injury,” said NIST researcher Scott Jackson. “There are 13 genetic markers, some of which can detect human feces, cattle, bird and dog feces. Therefore, we can isolate the fecal sources found in the feces. dirty water. ”
Each genetic marker of SRM interacts with a specific qPCR pathway designed to detect fecal contamination in a fluid sample. A qPCR – quantitative polymerase chain reaction – is a molecular test used to model a DNA model that relies on a single agent to explain the effects. Three of these tests are EPA -approved.
The qPCRs refer to two types of fecal contamination: the first to determine the amount of fecal matter in a sample, and the second to determine the cause of fecal contamination. Two qPCR pathways bind to fecal signaling bacteria, E. coli and Enterococcus, found in the fecal waste of most mammals. The remaining 11 qPCR pathways help identify factors such as human, cattle, dog, pig and bird fecal matter.
“This is a multiuse device. A future office can use this SRM to help determine if bath water is safe and find out what the causes are when fecal pollution occurs,” he said. Shanks.
What makes SRM think is that it has 13 genetic markers on a single piece of DNA, said NIST researcher Jason Kralj. This means that researchers can evaluate multiple qPCR effects from a water sample using a single standard.
The SRM can be used to help reduce the variability of water quality measurements between labs and to aid the lab approval process, which shows that the area is running smoothly. health department in its experiments. Although the SRM was developed to test the quality of fresh water, it can be used to support wastewater management, food monitoring, wastewater monitoring and reporting. On the roads, Shanks said.
A national interlaboratory study was conducted during the development of the SRM. In the future, NIST and EPA will release the results of the study, which is designed to evaluate the performance of SRM at the national level.
“Looking down the road, the mission of this partnership is to guide future organizations in the development of new resources that support the implementation of these practices. designed to protect health and natural resources, ”Shanks said.
DNA testing for fecal contamination
Presented by the National Institute of Standards and Technology
Directions: NIST works with EPA to develop standard for improving fecal contamination measurements in freshwater (2022, April 6) Retrieved 7 April 2022 from https://phys.org/news /2022-04-nist-collaborates-epa-standard- fecal.html
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