St. Helens Chronicle. The St. Helens woman has been missing for two weeks. Her boyfriend, currently in the Lane County jail for other offenses, is now considered a person of interest. Police are currently searching for St. Helens woman, Cheryl Hart, who has been missing for nearly two weeks.
First, there are typically two varieties, or species, of arsenic in water: arsenic 3 and arsenic 5.. This is significant because arsenic 3 is very difficult to remove from water and must be changed or oxidized to arsenic 5 before it can be removed.
The maximum permissible level of arsenic in drinking water is 10 mcg/L. Long-term exposure to arsenic in drinking water at a level of 50 mcg/L has been linked to reduced scores on intelligence tests in children.