Biomonitoring California measures chemicals with potential health or exposure concerns. For many of these chemicals, there is not enough information to know what levels found in people will cause health issues. However, for four metals: arsenic, cadmium, lead, and mercury, we have a better understanding of the levels that could harm health. We call these “levels of concern” (LOCs).
Follow-up for elevated levels of metals
Study participants with levels above the LOCs receive early notification and personalized guidance. This follow-up is done before the standard mailing of results materials sent to all participants and can include:
- additional laboratory analyses, such as speciation of arsenic
- notification about potential health concerns
- follow-up surveys to help participants and staff identify and reduce potential sources of exposure
- referral to public health staff or clinicians for follow-up, including home visits and additional testing
Why we have LOCs
LOCs provide context for individual results and summary statistics for our studies. They also help inform our framework for following up with study participants.
Our LOCs are mostly adopted from values used by the Centers for Disease Control and Prevention (CDC). We also consider the latest guidance and recommendations from other federal agencies as well as state and local partners and update our LOCs when needed.
Metals in urine and blood: LOCs and follow-up actions
| Urine metals | Level of concern | Notification letter | Phone contact (includes survey of possible exposure sources) |
|---|---|---|---|
| Total arsenic | ≥ 50 µg/L | ✓ | Only if also above inorganic arsenic LOC |
| Inorganic arsenic | ≥ 20 µg/L | ✓ | ✓ |
| Cadmium | > 3 µg/g creatinine | ✓ | ✓ |
| Mercury | ≥ 10 µg/L | ✓ | ✓ |
| Blood metals | Level of concern | Notification letter | Phone contact (includes survey of possible exposure sources) |
| Cadmium | ≥ 5 µg/L | ✓ | ✓ |
| Lead | 4.5 to < 9.5 µg/dL | ✓ | ✓ |
| Lead | ≥ 9.5 µg/dL | Follow-up by the CDPH Occupational Lead Poisoning Prevention Program (OLPPP) | |
| Mercury | ≥ 5.8 µg/L | ✓ | ✓ |
For more information
Biomonitoring California Protocol for Following up on Elevated Levels of Urinary Arsenic
