On March 22, 2019 a memorandum was issued by the Maine Department of Environmental Protection requiring all biosolids programs with licenses for beneficial use to both test for PFOA, PFOS and PFBS in their biosolids and to suspend any application of biosolids, including biosolids composts until after sampling and analysis confirm concentrations are less than DEP screening standards, or alternative requirements are met for cumulative loadings per Chapter 419 section 5. The following information is intended to supply basic factual information concerning these materials and how they relate to LAWPCA biosolids programs.
LAWPCA has been supplying biosolids to DEP licensed and permitted farm application sites since at least 1987 and supplied compost to customers for nearly 30 years. These programs have provided nutrients and other soil benefits and LAWPCA expects to continue to supply approximately 8,500 cubic yards of these materials to farms into the future.
PFAS compounds are a group of compounds in which fluorine atoms are bonded to carbon chains(the number of carbon atoms varies and with the number of carbon atoms in the chain, the properties also show considerable variation). They were developed in the early decades of the 20th century for their properties of shedding or repelling water and most fats and oils.
PFAS compounds have been widely used in consumer products (Teflon cookware, stain and fire retardants used in clothing, carpets and furniture, food packaging, ski wax, fire fighting foams, and even dental floss).
It is believed that over 99% of people worldwide have measurable levels of PFAS in their blood, and although production of the most common PFAS compounds (including the 3 targeted by the DEP memorandum) have been phased out of production in the United States (and many, but not all, countries) the presence of these compounds is still common worldwide. In any case, the levels measured in human blood has been decreasing. Data showed average combined PFAS and PFOA levels in human blood in the United States was 35 ppb in 1999 and 8 ppb in 2012.
Treatment plants do not use PFAS compounds in our treatment plants, nor do these facilities produce PFAS – treatment plants essentially reflect the chemical profiles of the communities they serve.
The state of the science regarding PFAS compounds is unsettled and rapidly expanding. This is true of analytical methods, health effects, and treatment technology. Much of this is due to the very small concentrations being considered – generally in the tens of parts per trillion(ppt) (one ppt in terms of time is 1 second in 31,700 years or in terms of volume, 1 drop of water in 20 Olympic swimming pools)
The US EPA issued a Health Advisory for two of the most common PFAS compounds combined (PFOA and PFOS) of 70 parts per trillion in drinking water. In the supporting documentation EPA stated numerous times that the advisory was not intended to be a limit or intended to be used to set limits for drinking water or any other media.
In 2018 Maine DEP set screening standards for PFAS in Chapter 418 Beneficial Use of Solids wastes. In Appendix A of that Chapter, included in the 165 compounds for which standards are list are PFBS at 1.9 mg/kg (ppb) dry weight, PFOS at 0.0052 mg/kg, and PFOA at 0.0025 mg/kg. These standards were set at one-half the risk standard used by the Department for clean up sites contaminated with hazardous substances.
Currently there is no EPA approved method for analyzing PFAS in any media other than drinking water. commercial laboratories have made various modifications to the approved drinking water method in order to analyze for PFAS in other media such as blood, food, biosolids and soils, however the possible error in these methods, as determined by “surrogate recoveries” has been as high as 150%.
Health effects from exposure to PFAS compounds are “probable links” and “correlations have been found” between PFAS compounds and health effects, but at this time causation has not been proven.
In one of the most often cited studies of people exposed to high levels of PFAS compounds from a manufacturing plant in Parkersburg, West Virginia, “probable links” to high cholesterol, ulcerative colitis, thyroid disease, testicular and kidney cancers were found. No link was found to hypertension or other cancers although other studies have claimed linkages to those other conditions.
Because these compounds have been so widely used as flame retardants/stain repellants in carpets and upholstery, one of the highest common sources of exposure to PFAS is through indoor dust. In a 2008 study by Stynar and Lindstrom, household dust from three daycare operations in the United States had an average concentrations of 142 ppb PFOA and 201 ppb PFOS.
LAWPCA is aware of the issues reported at the Stoneridge farm in Arundel, Maine and LAWPCA does not believe that the PFAS concentrations found in the groundwater and forage at this site was a result of applying municipal biosolids. More information on that site and PFAS in general may be found at the website of the North East Biosolids and Residuals Association: nebiosolids.org