Key stressors to the biological condition in streams can include increased concentrations of nutrients, dissolved metals, and organic chemicals. To investigate the influence these contaminants might have on stream health in the San Gabriel River Watershed, groups of these analytes were collected simultaneously with the BMI samples. A complete list of measured constituents can be found in the Project QAPP.

To determine if any of the constituents were measured in concentrations that might be of environmental concern, where possible, their concentrations were compared against established regulatory standards.

Click on this link to explore the concentrations of nutrients and metals in the subregions of the watershed.