Water Chemistry

Water Chemistry is perhaps the most commonly understood water quality parameter understood by the public. Simply put, water is measured for the concentration of different types of chemicals, both naturally occurring and man-made. EPA and it's partners in the States have established criteria for protection of human health and aquatic species. Concentrations above or near these criteria indicate problems with water quality. The Agency utilized two different means to collecting water chemistry information: Collecting grab samples of stream or river water to ship to the analytical laboratory, and obtaining in situ measurements of specific conductance, dissolved oxygen, and temperature.

Grab samples for nutrients, pesticides, polycyclic aromatic hydrocarbons (PAHs), and other pollutants were taken, preserved (if appropriate), placed on ice in coolers and transported at 4°C to the Region 7 laboratory for analysis. Samples were analyzed according to EPA Region 7 SOPs. Chemistry parameters were updated each year to accommodate laboratory changes and based on an assessment of new parameters of interest. In situ (in-stream) measurements were temperature, pH, conductivity, dissolved oxygen and turbidity at the time of the above mentioned grab sample. A Horiba U-10 Water Quality Checker was calibrated prior and used to measure all in situ water quality parameters.

Sediment Chemistry

Water quality is also dependent on sediment chemistry which is closely linked to water column chemistry. Pollutants can become entrained with particulate matter and settle into sediments where aquatic species live, and where they can be re-suspended into the water column.

One 8 ounce grab sample was collected at each monitoring site. Representative samples were collected near each transect with a clean stainless steel sampling spoon. The collected sediment was placed in a foil pie pan and homogenized prior to transferring to a labeled 8 ounce glass container. Samples were placed in coolers on ice and transported to the Region 7 laboratory at 4°C for analysis of pesticides, herbicides, metal and PAHs (transportation related chemicals).