Analytical Methodology Development
What is this project and why are we doing it?
Program staff work closely with the MDH Public Health Laboratory (PHL) to better understand the analytical challenges posed by contaminants and ensure methods are available to test for contaminants in water. One recent example occurred when MDH lowered the health based guidance for 1,2,3-Trichloropropane (1,2,3-TCP) (PDF:98KB/7 pages) from 40 parts per billion (ppb) to 0.003 ppb. Analytical methods at the MDH PHL for measuring 1,2,3-TCP in water were not able to detect 1,2,3-TCP at this low level. Past monitoring for 1,2,3-TCP used detection limits that were higher than 0.003 ppb, typically around 4 ppb. Therefore, it was unclear if there were concentrations of 1,2,3-TCP in water in Minnesota between 4 ppb and 0.003 ppb.
CEC program staff coordinated with the PHL to find an analytical method that could measure 1,2,3-TCP at or below 0.003 ppb. It turned out to be more efficient and cost-effective to locate a certified outside laboratory that could meet MDH’s requirements. Arrangements were made to send samples through the PHL to the outside laboratory. CEC program staff coordinated with staff from the Minnesota Department of Agriculture (MDA), the Minnesota Pollution Control Agency (MPCA), and other MDH programs to choose sampling locations. Groundwater samples were collected from four agricultural monitoring wells, one closed landfill monitoring well, and eight non-community public wells. These samples were analyzed by a laboratory in California that could measure 1,2,3-TCP at 0.0007 ppb, well below the MDH guidance value.
What were some key outcomes?
Long-term outcomes from this coordination will include increased capacity at the PHL to develop analytical methodologies and to analyze water samples for contaminants of emerging concern, including those collected by other state agencies. In the case of 1,2,3-TCP, it was not found at levels above 0.0007 ppb in any of the samples.
How will MDH use this information?
In the case of 1,2,3-TCP, because of the limited number of samples collected, the question still remains as to whether 1,2,3-TCP is in Minnesota groundwater at levels of concern. MDH anticipates more sampling at other locations and will continue to coordinate with staff from MDA, MPCA, and the PHL as applicable.