[USCC] Response to Reilly regarding Adelanto site

[Rufus Chaney]

Dear Ms. Reilly:

I was confused about the site you named and thought it was the case from years ago in which a massive pile of biosolids was accumulated by a contractor on an Indian Reservation site in CA. At that site there may have been some composting, but it was eventually a massive pile and was the subject of a stop action order and all biosolids were eventually removed. Those were Class B. And illegal. But the regulation of biosolids on Indian lands was a legal complication that took some time to work out.

So I looked up the Adelanto site on the web. I found a report from the CA Dept. Health Services, Environmental Health Investigations Branch at http://cc.msnscache.com/cache.aspx?q=3878638985579&lang=en-US&mkt=en-US&FORM=CVRE3
     This letter says the site was in compliance with 503, but that 503 does not regulate gaseous emissions of composting sites. They note apparent violation of particulate dust (PM10) in excess of CA limits to an immediately off site location but noted that populations were distant from the edge of the composting site.

>From this letter, I suspect you have been in contact with anti-biosolids forces in southern CA; the description of the problem in the official letter is different from your description. Most of the singnificant exposures would have been to workers, not to the neighborhood. It was a windrow composting operation, and dusty. Because of dry air in CA, windrows may need to be watered to maintain optimum water content for composting, and for dust control. Well managed sites have water trucks working day and night to keep down dust emissions. During windrow composting operations, pathogens remain for some time because multiple turnings while the piles exceed 55C are required to achieve Class A pathogen reduction. During an official visit, malodor was noted when piles were turned, but not severe malodors.

I have no special information or comment about this site and their operations. They were visited repeatedly by the County/State Health Department, and EPA Regional staff were kept informed. If they are in violation of their requirements, regulatory actions will or have occurred. The official letter I note above was from May 5, 2005. 

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Now, I'd like to address the point you have noted about extreme risk of lethal infections at Hospitals in the US/North America which you suggest result from dispersal of anti-bacterial compounds in biosolids/compost products. And this connects with Mr. McGowans's comments about anti-bacterial compounds in biosolids.

If there is a public health problem from use of anti-bacterial compounds in consumer products, where is the highest exposure and selection of resistant organisms occurring? Surely at the point where concentrations are highest, in our homes and on our bodies. When the anti-bacterials are diluted in wastewater and either biodegraded, metabolized and residues partially accumulated in biosolids, the concentrations are very much lower than in the consumer products.

So, I would reason that if there is a significant risk from use of anti-bacterials in consumer products, the proper action would be to seek the termination of such use. Not to claim risks from anti-bacterial residues in biosolids utilization and composting. When chemicals used in industry or consumer products are found to be unacceptable in the environment, they are prohibited (DDT, PCBs, etc.). Trace levels in biosolids were seldom the important source of exposure which required action, although highly contaminated biosolids were identified and land applications termination until pretreatment or termination of the chemical use improved biosolids quality. Some dangerous chemicals are used in industry which require on site destruction without discharge to the sewers. 

So please don't yell at POTW/biosolids folks or composters about traces of anti-bacterials in composts and biosolids, levels which are readily biodegraded in the soil environment. Focus your attention on production and use of consumer products which contain these compounds. If these compounds do increase the risk of infections in the general population, FDA will eventually act. 

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Now, what about your claim of an adverse effect of biosolids related to hospitals and infections? The concern about hospital infections is well known. Again, the selection of resistant organisms seems to be related to the concentration of organisms in hospitals, and to the intense use of anti-bacterials and bactericidal agents in hospitals. Perhaps incomplete treatments with bactericidal agents causes selection of resistant organisms. And susceptible hosts in the hospital help maintain colonies within hospitals. 

If you follow the logic I have summarized, you should see that hospital infections and deaths are simply not a problem caused by biosolids or composts. The problem you raise is a difficult social issue; some industries manufacture and sell anti-bacterial products for home use; advertizements abound even for sprays to kill airborne bacteria in the home. Both organic anti-bacterials and general bactericidal products are commonly used to remove microbial contaminants in the kitchen and bathroom. Citizens need to be able to clean the surfaces in their homes to remove microbial contamination, so at least some of these will continue in use. If chlorox type cleaner/killers are to be preferred to organic chemicals which leave residues for human exposures, perhaps you can focus on that message rather than your claims that biosolids and composts are dangerous because they contain traces of anti-bacterial compounds.

In my view, this round of discussion of anti-bacterial compounds in biosolids and composts followed the publication of a paper in Environmental Science and Technology and a well crafted press release about triclocarban.. They provided no evidence that the residue of the anti-bacterial in biosolids could comprise a risk, just that it was present. They did not summarize evidence that the compound is readily biodegraded in aerobic soils even though it persisted during anaerobic digestion, a result seen with other xenobiotics and oils. And they failed to note the high exposures which occur at the point of use in the home. I argue that such claims are inappropriate at this stage of research, but such language is important to researchers who are seeking more $ to continue to study trace levels of consumer products in the general environment.

Heidler, J.; Sapkota, A.; Halden, R.U. 2006. Partitioning, Persistence, and Accumulation in Digested Sludge of the Topical Antiseptic Triclocarban during Wastewater Treatment. Environ. Sci. Technol. 40(11):3634-3639.
     "The topical antiseptic agent triclocarban (TCC) is a common additive in many antimicrobial household consumables, including soaps and other personal care products. Long-term usage of the mass-produced compound and a lack of understanding of its fate during sewage treatment motivated the present mass balance analysis conducted at a typical U.S. activated sludge wastewater treatment plant featuring a design capacity of 680 million liters per day. Using automated samplers and grab sampling, the mass of TCC contained in influent, effluent, and digested sludge was monitored by isotope dilution liquid chromatography (tandem) mass spectrometry. The average mass of TCC (mean ( standard deviation) entering and exiting the plant in influent (6.1 ( 2.0 íg/L) and effluent (0.17 ( 0.03 íg/L) was 3737(694 and 127(6 g/d, respectively, indicating an aqueous-phase removal efficiency of 97 ( 1%. Tertiary treatment by chlorination and sand filtration provided no detectable benefit to the overall removal. Due to strong sorption of TCC to wastewater particulate matter (78 ( 11% sorbed), the majority of the TCC mass was sequestered into sludge in the primary and secondary clarifiers of the plant. Anaerobic digestion for 19 days did not promote TCC transformation, resulting in an accumulation of the antiseptic compound in dewatered, digested municipal sludge to levels of 51 ( 15 mg/kg dry weight (2815 ( 917 g/d). In addition to the biocide mass passing through the plant contained in the effluent (3 ( 1%), 76 ( 30% of the TCC input entering the plant underwent no net transformation and instead partitioned into and accumulated in municipal sludge. Based on the rate of beneficial reuse of sludge produced by this facility (95%), which exceeds the national average (63%), study results suggest that approximately three-quarters of the mass of TCC disposed of by consumers in the sewershed of the plant ultimately is released into the environment by application of municipal sludge (biosolids) on land used in part for agriculture."

Regards,

Rufus Chaney
Beltsville, MD