BAY MINETTE, Ala. — The Baldwin County Commission is waiting for an ADEM review regarding arsenic and vinyl choride traces discovered last year at Magnolia Landfill, but solid waste manager Jim Ransom said Tuesday the contamination source probably is outside the Summerdale site.

Ransom told Baldwin County Commissioners Tuesday that if ADEM accepts a Dec. 22 work plan staff will bring before the Baldwin County Commission an addendum to the master services agreement between Baldwin County and engineers.

If adopted by the Baldwin County Commission, the master services agreement addendum will allow activities related to the stepped-up work plan to commence.

“Statistically significant” levels of arsenic and vinyl chloride were noted last year, but Ransom said the chemicals might be a “naturally occurring phenomenon” and seasonal.

Commissioners ordered continual monitoring to determine more specific extent and content of the groundwater migration.

The county received a letter from the Alabama Department of Environmental Management (ADEM) dated Nov. 17, addressing the results of a March 2011 groundwater monitoring event at the Magnolia Sanitary landfill. The Magnolia Sanitary landfill uses six groundwater monitoring wells for the collection of groundwater samples.

Samples collected from two wells returned a statistically significant increase for arsenic and vinyl chloride.

Ransom said the arsenic may be related to the seasonal rise and fall of groundwater coming into contact with naturally occurring arsenic in the soil.

ADEM officials said the semi-annual groundwater monitoring report in March has been reviewed at the request of the Commission and that corrective measures should be taken.

Ransom said an alternate source study has been submitted to ADEM and that boring samples will begin as soon as approval has been received.