MA Updates Biosolids Molybdenum Standard
It's official: the Massachusetts biosolids standard for molybdenum (Mo) is now 40 mg/kg. Over the past 16 months, the Department of Environmental Protection (MassDEP) reviewed the science, proposed a draft regulation change this spring, took public comment, and finalized the change effective a week ago. This is based on scientific risk assessment and is consistent with, for example, the standard in New York.
In June 2005, NEBRA brought together stakeholders in a workshop at which research scientists George O'Connor (University of Florida), Gary Van Riper, and Rufus Chaney (USDA) reviewed their work on the risks of molybdenum in soils and molybdenosis in ruminants. Their work showed that the former MassDEP standards for Mo in biosolids - a maximum of 25 mg/kg, and 10 mg/kg if used on land for ruminant feed - were outdated.
The new regulations also contain a requirement that the end user of the biosolids be informed of the small potential risk of molybdenosis under certain conditions.
The new, revised 310 CMR 32.00 "sludge" regulations are available at http://www.mass.gov/eea/agencies/massdep/water/regulations/310-cmr-32-00-land-application-of-sludge-and-septage.html