Investigate sources of pollution

Finalize the pollutant source investigation spreadsheet for the creek sampling: enter lab results for sites C1 through C8, calculate exceedances against the regulatory thresholds, assign a likely source ranking for each site, and send the file to Priya in environmental compliance with a one-day advisory note on sites exceeding thresholds.

Before I forward the investigation to compliance, make the findings easy to act on: put exceedance counts and the top three contaminants at the top, make thresholds and units obvious next to each result, flag any inconsistent sampling dates or missing chain-of-custody entries, and call out sites where multiple contaminants indicate the same upstream source so Priya can prioritise field follow-up.

Site C5 returned high nitrate and copper simultaneously, which is unusual. I’m worried this indicates a mixed source like agricultural runoff plus illegal disposal, but I don’t know if the lab mixed samples or if the field notes missed a spill. I can’t tell whether to treat it as lab error or a real mixed-source event. What’s the most likely diagnosis and the immediate steps to confirm it before recommending a response to Priya?

We keep wasting days chasing lab results because field teams omit sample times, sampler initials, or site photos; over the past year that added a week to investigations. What one change to the sample intake procedure and one habit for field teams should I implement so future lab results are actionable on arrival and reduce back-and-forth with compliance?