California Department of Health Services

                 The Environmental Health Investigations Branch
General concerns about biosolid composting and land application:
Environmental Health Investigations Branch / 1515 Clay Street, Suite 1700, Oakland, CA 94612
(510) 622-4500
Internet Address:

May 5, 2005

Mr. Doug
Larkspur Road
Adelanto, CA 92301

Dear Mr.

The Environmental Health Investigations Branch (EHIB) of the Department of Health Services
(DHS) is writing in response to your request for assistance in addressing health concerns
related to operations at the Nursery Products, LLC (hereafter “Nursery Products”) biosolids
(sewage sludge) composting facility in Adelanto, California. In April 2004, you contacted the
federal Agency for Toxic Substances and Disease Registry (ATSDR) for assistance in
addressing potential exposure and health concerns from the facility. DHS works under a
cooperative agreement with ATSDR and is following up on your request.

Since April 2004, DHS staff has spoken with you on several occasions about health concerns
you believe to be related to airborne exposures from Nursery Products. In July 2004, Tivo
Rojas, a Health Educator with DHS, met with you along with other members of the Nursery
Products Citizens Oversight Committee and participated in a tour of the Nursery Products
facility. DHS staff noted that a great deal of dust was being generated during the windrow
(piles of compost) turning process. Some odors were smelled in areas where the windrow
turning was being conducted, but overall odors were characterized as being minimal.

To evaluate potential exposures, DHS staff obtained and reviewed the following

U.S. Environmental Protection Agency (USEPA) Plain English Guide to the EPA Part 503
Biosolids Rule, September 1994;
Nursery Products Annual Report (2004) and February 2005 monitoring results;
San Bernardino County Environmental Health monthly inspection reports (February 2002 -
January 2005);
Final Report: Air Monitoring at the Adelanto Converter Station, Los Angeles Department of
Water and Power, January 12, 2005;
Laboratory report of runoff water from Adelanto Nursery: Los Angeles Department of Water
and Power, March 31, 2005; and
Limited review of the scientific literature as related to biosolids composting and land

General concerns about biosolid composting and land application:

In 1993, the USEPA established regulations (Code of Federal Regulations Title 40, Part 503—
commonly referred to as Rule 503) governing composting and land application of biosolids.
Public health concerns related to these activities are increasing as facilities and land
application sites become more prevalent. In 2002, the National Research Council (NRC) of the
National Academy of Sciences released a report concluding that the potential adverse human
health impact from exposure to biosolids is uncertain and there is a need for the USEPA to
update the scientific basis of Rule 503. The NRC recommended the USEPA conduct additional
studies looking at potential chemicals of concern in sewage sludge that are not currently
regulated. The NRC also recommended that a number of activities be conducted related to
pathogen/disease causing microorganisms (bacteria, viruses, and parasites) standards, as
there is question to whether “current management controls are adequate to maintain minimal
exposure concentrations over an extended period of time.” Rule 503 was implemented without
an evaluation of the health risks from exposure to pathogens. The NRC stressed the need for
USEPA to develop effective ways to monitor specific pathogens and evaluate the potential for
regrowth of pathogens and bacterial toxins (endotoxin and exotoxins) that may occur after the
waste treatment process (NRC, Gattie 2004). Concerns have also been raised about exposure
to volatile chemical emissions, which are not regulated under Rule 503.

In studies discussing potential exposure to pathogen-contaminated dust and runoff water from
land-applied biosolids and composting (biosolids and green/yard waste), the health concerns
reported by the adjacent communities show similar patterns (NRC 2002, Herr 2002).
Symptoms commonly reported include respiratory infections, skin rashes, burning eyes,
burning lungs, difficulty breathing, and gastrointestinal effects. These effects can be more
severe in immunocompromised individuals, individuals with chronic disease, and other
sensitive populations. Similar health effects have been observed in workers at composting and
sewage treatment facilities. In some studies, workers have been shown to have higher rates of
airway mucous membrane complaints, respiratory inflammation, skin rashes, and diseases
involving immunological hypersensitivity reactions (Gattie 2004, Herr 2002). In a cross-
sectional study, researchers investigated effects of bioaerosol (organic dusts - mixtures of air
and microorganisms) polluted outdoor on airways of residents living next to a composting
facility in Germany. Researchers compared self-reported health complaints to measurable
bioaerosol pollution in residential outdoor air. The microorganisms measured in the study
included, total bacteria, molds, thermophilic and thermotolerant actinomycetes. The study
found detectable levels of bioaerosol pollution at a distance of 550 meters (maximum distance
sampled in study), with the highest levels measured closest to the site. All exposure groups,
including residents living the furthest away from the site (> 400-500 meters / ~1/3 mile)
reported higher rates of health complaints compared to the unexposed controls. Researchers
concluded, “this bioaerosol exposure in turn could be associated, as far as concentrations of
bioaerosols and duration of exposure were concerned, with symptoms suggestive of airway
inflammation also reported in respective workplaces” (Herr 2002).

Specific concerns about Nursery Products

In February 2002, Nursery Products was permitted and operations began in November of that
same year. Based on the Nursery Products’ permit, the facility generates/prepares up to 1,440
cubic yards per day of compost. The facility uses green waste and mostly Class B (designation
with respect to pathogens) biosolids in their process. Pathogen levels in Class B biosolids are
partially reduced (~90%) at the sewage treatment plant of origin. Through the composting
process, pathogen levels are further reduced so that the finished product meets Class A
designation. Under Rule 503, if pathogens are below detectable levels, then the biosolids meet
the Class A designation.

DHS is aware that there have been numerous (in the hundreds) community complaints about
odors, flies, and dust due to operations at Nursery Products. There have also been anecdotal
reports of nausea, increases in bloody noses and respiratory effects in school children at
Bradach Elementary School, believed to be due to releases from Nursery Products. According
to county staff, Nursery Products addressed the fly and odor issue by changing their
composting process (J. Adams, San Bernardino County Environmental Health, personal
communication, February 24, 2005). We were also informed that Nursery Products is
relocating its operation at some point this coming summer or fall. It is unclear whether the
current location in Adelanto will be used for storage of composted material.

CDHS reviewed available data (listed above), in an effort to understand whether operations at
the Nursery Products facility could be impacting public health. The first step is to determine
whether there is a pathway for people to be exposed to contaminants from the site. DHS
identified two potential pathways of exposure: 1) airborne releases of contaminants and 2)
dust  surface water runoff.

The only surface water sampling obtained by DHS was collected by the Los Angeles
Department of Water and Power, at the Adelanto Converter Station (ACS) on February 12,
2005 and February 24, 2005. The ACS is located on the adjacent property directly north of
Nursery Products. Six samples of runoff water from four locations on the ACS property were
collected and measured for total coliforms, fecal coliforms, and Escherichia coli (E-coli). The
laboratory analysis revealed high levels of these pathogens in all of the samples—total
coliforms ranged from 300,000 to 1,100,000 MPN/100 ml (most probable number per 100
milliliters of water); fecal coliforms ranged from 50,000 to 800,000 MPN/100 ml, and E-coli
ranged from 50,000 to 280,000 MPN/100 ml.

There are no health-based standards that directly apply to this situation. As a means of
comparison, we reviewed draft water quality standards for pathogens that apply to recreational
waters (places where people swim or are likely to come into contact with water). The DHS Draft
Guidance for Fresh Water Beaches describes bacteria levels that may require posted warning
signs in order to protect public health. The closest scenario provided in the guidelines applies
to storm drain waters adjacent to a “public beach,” which includes rivers, streams, and creeks.
The following table lists the guidelines for “fresh water beaches” and adjacent storm drains
and the range of pathogens detected in runoff water samples collected on the ACS property:


As shown, the levels of pathogens detected in runoff water collected at the ACS exceed
guidelines for fresh water beaches and adjacent storm drains. It is possible that if someone
(most likely ACS employees) were to have come into contact and ingest the runoff water
(during the days and at the locations the samples were collected) they could have experienced
flu like symptoms such as gastrointestinal distress, nausea, and vomiting. Since the facility is
located in an area that is fairly remote with respect to residential populations, it is not likely that
these types of exposures occurred to residents, but possibly to ACS employees.

From May 11, 2004, to October 21, 2004, Applied Measurement Science a consultant hired by
the Los Angeles Department of Water and Power conducted air monitoring at the ACS
property. The main purpose of the air monitoring was to understand the magnitude of dust
impacts from Nursery Products on the ACS property. The air monitoring activities included
collection of meteorological (MET) data (wind patterns), continuous hourly PM 10 (particulate
matter less than 10 microns in aerodynamic diameter) measurements, directional integrated
PM 10 (24 hour or longer periods) when ASC was determined to be downwind of Nursery
Products, conductivity and ionic composition of dust. There were no samples measured for
volatile chemicals. The authors of the report did note that on many days they smelled odors
“immediately upon entering the ACS property on the north side of the site, several hundred
yards from the Nursery Products facility.”

The ACS property is considered downwind of Nursery Products, as the prevailing wind
direction is from the south / south-south west. At the ACS property, the 24-hour average
California Ambient Air Quality Standard of 50 mg/m3 (micrograms per cubic meter air) was
exceeded 74% of the time. At times, hourly concentrations were measured in excess of 1000
mg/m3, with an average hourly PM 10 concentration of 123 mg/m3. The report shows that 68%
of the hourly PM 10 measurements were for sectors originating at Nursery Products. The
average PM 10 concentration at all the other locations (non-downwind) was 48.8 mg/m3.

From a public health perspective, PM 10 is considered among the most harmful of all air
pollutants, that “when inhaled, these particles evade the respiratory system's natural defenses
and lodge deep in the lungs.” (CARB). Potential health effects include exacerbation of asthma,
reduced immune function, bronchitis, and other lung diseases. Sensitive populations (children,
people with chronic disease, the elderly, and exercising adults) are more susceptible to these
effects. According to the California Air Resources Board, recent studies suggest a link
between PM 10 exposure and premature death in people suffering from heart and lung
disease, especially the elderly.

It is not possible to determine whether PM 10 concentrations were elevated in other areas of
Adelanto. The data does show that during the time period measured, operations at Nursery
Products were responsible for generating a great deal of dust. Studies on the global transport
of dust have shown that dust, especially small particles, have the ability to travel great

As mentioned earlier, there is a concern about potential exposure to pathogen-contaminated
dust. There is no site-specific air monitoring data measuring pathogens in dust. The
monitoring data (finished compost and temperature data collected during the composting
process) that is available indicates the facility is in concurrence with requirements under Rule
503 at the time of those sampling/monitoring events. However, while these data may indicate
that the finished compost meets pathogen requirements, it does not rule out the possibility for
pathogens present in pre-composted materials to become airborne on dust and other

Another potential exposure concern relates to inhalation of volatile chemicals. A number of
volatile chemicals, ammonia, hydrogen sulfide, and other sulfur and nitrogen based
compounds are released from composting facilities. Currently, there are no monitoring
requirements for these chemicals under Rule 503. In the Los Angeles area, the South Coast
Air Quality Management District recognized the composting industry as a significant source of
air pollution for criteria air pollutants and adopted measures (regulations) to reduce
composting emissions. The City of Adelanto falls with in the jurisdiction of the Mojave Desert
Air Quality Management District (MDAQMD). The MDAQMD has not adopted any volatile
chemical emission standards associated with composting. Given the numerous odor
complaints documented, it is clear that airborne releases of certain compounds occurred.
However, DHS could not evaluate these exposures and potential health implications due to a
lack of data.

In summary, we could not quantify exposures to site-related compounds due to a lack of data.
However, there is sufficient information both site-related and in the scientific literature to
suggest the possibility for some Adelanto residents (depending on time and location) to have
been exposed to airborne contaminants (volatile chemicals), and dust originating from Nursery
Products. While it is not possible to determine whether the health effects you have
experienced were/are caused by exposures from Nursery Products, some of the symptoms you
have expressed to DHS are consistent with biosolid-related exposures documented in the
scientific literature.

Next Steps

DHS plans to make further inquiry with the various agencies (city, county, state, and federal),
along with experts in the field, to explore ways in addressing public health concerns around
this issue. As acknowledged by the NRC, the USEPA, and other experts in the field, many
uncertainties need to be addressed in understanding the full range of public health issues
associated with land application and composting of biosolids. We recognize that it may take
years to answer these important questions. Thus, we believe it is prudent to explore the
possibility for implementing precautionary measures at the local level.

We will keep you informed of our progress. If you have any questions, please do not hesitate
to call Tracy Barreau (510) 622-4489.


Tracy Barreau, REHS
Senior Environmental Scientist
Environmental Health Investigations Branch

Marilyn C. Underwood, Ph.D.
Acting Chief, Site Assessment Section
Environmental Health Investigations Branch

cc        Ms. Leslie Campbell
  Agency for Toxic Substances and Disease Control
  1600 Clifton Road, MS-E32
  Atlanta, GA 30329

Ms. Libby Vianu
Regional Representative
Agency for Toxic Substances and Disease Control
75 Hawthorne Street, Suite 100, HHS-1
San Francisco, CA 94105

Ms. Jackie Adams
County of San Bernardino
Environmental Health Services Division
385 North Arrowhead Avenue
San Bernardino, CA 92415-0160

Mr. Kevin Murphy
City of Adelanto
Department of Building and Safety
11600 Air Expressway
Adelanto, CA 92301

Ms. Lauren Fondahl
U.S. Environmental Protection Agency
75 Hawthorne Street
San Francisco, CA 94105

Mr. Ron Holtz
Adelanto Converter Station
Los Angeles Department of Water and Power
16800 Aster Road
Adelanto, CA 92301

Blind cc:

Ms. Jennifer Edge
Environmental Services
Los Angeles Department of Water and Power
111 N. Hope Street, Room 1050
Los Angeles, CA 90012
Range of Pathogens
Detected in Runoff
(MPN/100 ml)
Fresh Water Beach
(MPN/100 ml)  
Storm Drain
(MPN/100 ml)  
Total Coliform
300,000 - 1,100,000
1,000 (if ratio of
fecal/total exceed
Fecal Coliform  
50,000 - 800,000
E. coli:
50,000 - 280,000