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.
Several types of cancer have been linked to arsenic in water. In 2001 the US Environmental Protection Agency lowered the maximum level of arsenic permitted in drinking water from 50 micrograms per liter (ug/L) to 10 ug/L.