| #P001 | chemical | health | guideline | Arsenic | drinking water | MAC | 0.01 mg/L | Equivalent to 10 µg/L. This value is the result of a risk management decision, since it exceeds the health-based guideline value. | | high |
| #P002 | chemical | health | recommended | Arsenic | drinking water | treatment_goal | 0.3 µg/L | The concentration of arsenic in drinking water representing an essentially negligible risk. Levels of arsenic in drinking water should be as close as possible to this level. | | medium |
| #P003 | unknown | operational | guidance | Arsenic Practical Quantitation Level (PQL) | drinking water | requirement | 0.003 mg/L | Based on the ability of laboratories to measure arsenic within reasonable limits of precision and accuracy. | | high |
| #P004 | design | treatment | mandatory | Residential Arsenic Treatment Device Certification | drinking water | requirement | 0.01 mg/L | Performance standard for residential scale treatment devices. | Certification criteria for residential devices available to date | high |
| #P005 | operational | treatment | guidance | Municipal-scale treatment arsenic removal capability | drinking water | treatment_goal | 0.001-0.005 mg/L | Removal level achievable by several advanced municipal-scale treatment processes. | Municipal-scale application | high |
| #P006 | operational | treatment | guidance | Small to mid-sized community treatment arsenic reduction | drinking water | treatment_goal | < 0.003 mg/L | Concentrations achievable using alternative processes such as adsorption and membrane systems. | Small to mid-sized communities | high |
| #P007 | chemical | health | guidance | Essentially negligible lifetime cancer risk range | drinking water | requirement | 10-5 to 10-6 dimensionless | The range defined as 'essentially negligible' for estimated lifetime cancer risk associated with arsenic ingestion. | | high |
| #P008 | chemical | unknown | guidance | Arsenic naturally found in waters | drinking water | unknown | 0.001 - 0.002 mg/L | Background levels naturally found in waters, though it may occur in much higher concentrations. | | high |
| #P009 | chemical | unknown | guidance | Arsenic levels in Canadian drinking water | drinking water | unknown | < 0.005 mg/L | Data collected indicate that levels in Canadian drinking water are generally below this threshold. | | high |
| #P010 | chemical | health | guidance | Estimated lifetime risk for arsenic at 0.01 mg/L | drinking water | requirement | 3.0 x 10-5 to 3.9 x 10-4 dimensionless | Based on the incidence of internal (lung, bladder, liver) cancers in individuals in southwestern Taiwan. | Derived by multiplying the unit risk by the MAC | high |