Report to /
Rapport au :
Environmental Services Committee /
Comité des services de l’environnement
and Council / et au Conseil
26 March 2002 / le 26 mars 2002
Submitted by / Soumis par : Dick Stewart, General
Manager /Directeur Général People Services Department/ Services aux citoyens
Contact/Personne-ressource : Dr. Robert Cushman, Medical
Officer of Health /
Médecin
chef
Public Health and Long-Term Care / Santé publique
et des soins de longue durée
724-4122 ext.
23684
Robert.Cushman@city.ottawa.on.ca
|
Ref No: ACS2002-PEO-HEA-0004 |
SUBJECT: A
Review of Land Application of Biosolids in the City of Ottawa
OBJET
: Un examen de l’épandage des biosolides
sur le sol dans la Ville d’Ottawa
REPORT RECOMMENDATIONS
That
the Environmental Services Committee and Council approve that:
1.
The
Medical Officer of Health recommends continuing land application of biosolids
in the City of Ottawa with implementation of proposed Best Management
Practices;
2.
To
ensure optimum program management, TUPW staff will undertake a yearly review of
the Biosolids Land Application Program starting at the end of the 2002 land
application season;
3. The Medical
Officer of Health will continuously monitor new and emerging scientific
literature on biosolids and report back to TUPW staff and Council accordingly.
RECOMMANDATIONS DU RAPPORT
Que le Comité des services de
l’environnement et le Conseil municipal approuvent que :
1. le médecin chef en
santé publique recommande de continuer l’épandage des biosolides sur le sol
dans la Ville d’Ottawa en mettant en oeuvre les meilleures pratiques de gestion
proposées;
2. le personnel de
TSTP effectue un examen annuel du Programme d’épandage des biosolides sur le
sol à partir de la fin de la saison d’épandage de 2002 afin d’assurer une
gestion optimale dudit programme;
3. le médecin chef en
santé publique se tienne informé, de façon continue, de toute nouvelle
documentation concernant les biosolides et fasse rapport au personnel de TSTP
ainsi qu’au Conseil municipal en conséquence.
In
December 2001, Ottawa City Council instructed the Medical Officer of Health to
retain experts to conduct a scientific review of the safety of spreading
biosolids on farmland, and to develop standards for land application of
biosolids that meet or exceed current Province of Ontario guidelines.
Biosolids,
also called sewage sludge, are a byproduct of the sewage treatment process at
Ottawa’s R.O. Pickard Environmental Centre.
They are formed by separating solids from wastewater and by conversion
of soluble organic pollutants to biomass.
These solids are then stabilized, which reduces the concentration of
pathogens (disease-causing organisms).
The
R.O. Pickard Environmental Centre produces roughly 40,000 wet tonnes of
biosolids every year – or four truckloads a day. Approximately 20,000 tonnes are spread on local farm fields
free-of-charge for use as a fertilizer alternative to farmers. Because biosolids cannot be spread in winter
and there is no local storage facility, the remaining tonnes are exported to
composting facilities and other re-use options outside the City.
Biosolids
contain nutrients including nitrogen and phosphorus, and for that reason the
material enriches soil and improves crops.
Currently, demand from farmers for biosolids surpasses supply. Members of the public have raised concerns
about potential human health and environmental risks of applying biosolids to
land. The current wastewater treatment
does not completely eliminate pathogens or all of the pollutants in the raw
sewage, which includes waste from industry.
Research on the subject is ongoing, particularly with regard to
substances that may be found in biosolids such as pathogens, some metals,
estrogenic hormones, pharmaceuticals and flame retardants called PBDEs.
Of
the biosolids generated at the 50 largest sewage treatment plants in Canada,
approximately 45 per cent, or 2 million tonnes per year (on a dry weight basis)
are applied to land. In Ontario,
biosolids have been spread on farmland for several decades. Last year, the City
of Ottawa’s Biosolids Program spread on 27 farm sites, representing less than
one percent of the City’s total agricultural acreage. Note that five years must
pass before a second spreading takes place on a site, and repeats to date are
rare.
Ottawa’s
current biosolids program was approved in 1997 and underwent an extensive
review and update in 2001. This review
entailed many public consultations.
Under the updated plan, staff recommended that the existing program
continue in the short term.
As
a result, Ottawa City Council accepted the Biosolids Management Plan Update in
December 2001. The recommendations of
the Management Plan update were the following:
·
Continue to manage the
disposal of municipal biosolids consistent with the principle of beneficial reuse
·
Develop multiple end
uses
·
Develop a biosolids
Environmental Management System
·
Strengthen the Sewer
Use Control Program
·
Initiate further
research into key areas
·
Develop a Biosolids
Management Public Awareness and Communication Plan that provides ongoing
information about the Biosolids Management Plan
At
the same time, Council directed the Medical Officer of Health to retain experts
to conduct a scientific review of the safety of spreading biosolids, then
present the analysis and new standards to the Environmental Services
Committee. Meanwhile, no biosolids
would be applied to agricultural land until the Medical Officer of Health’s
report was received.
The
Medical Officer of Health hired the services of Apedaile Environmental
Management and CH2M Hill Canada Limited because they had done previous work on
this issue. They were assigned to
compile current literature on health aspects of biosolids, interview
researchers, and develop – in consultation with City Staff - Ottawa-specific
Best Management Practices. To assist
the Medical Officer in his determinations, a third party expert (Dr. Donald
Cole, M.D., an environmental health specialist at the University of Toronto)
was brought in for his advice on the project.
More details on this can be found below.
DISCUSSION
Throughout
history, societies have struggled to find ways of coping with human waste.
Every resident of Ottawa helps produce what eventually ends up at the sewage
treatment plant, making this a community issue. Biosolids will not disappear – they need to be placed somewhere
in a manner that has the least negative impact on public health and the
environment. Beneficial re-use of
biosolids can be regarded as a long-term means of promoting a sustainable city.
Because
biosolids contain many substances and are applied to a complex environment,
uncertainties exist, and these uncertainties will likely exist for years to
come. New concerns will no doubt arise,
as land application is a developing practice that is subject to an increasing
amount of research. Therefore, using
the words ‘safe’ or ‘unsafe’ to describe the use of biosolids is simplistic and
unwise. Instead, any assessment of a
biosolids program should be based on the potential for benefits and the
management of potential risks.
To
ensure optimum management, staff of the Transportation, Utilities and Public
Works Department (TUPW) will undertake an annual review of the Biosolids Land
Application Program starting directly after the end of the 2002 application
season. The review will monitor
compliance of the Best Management Practices and propose changes if
required. Furthermore, the Medical
Officer of Health will continuously monitor new and emerging scientific
literature on biosolids and report back to TUPW staff and Council accordingly. In this way, the public can be assured that
practices are based on the latest research findings and that protection of
public health remains paramount.
Below
is a brief summary of the full review conducted by Apedaile Environmental
Management and CH2M Hill Canada Limited.
Please refer to the full report, entitled “Health Aspects of
Biosolids Land Application,” for a more
detailed examination. The report
contains three main sections – 1)Methodology
2)Scientific Review 3) Best
Management Practices.
Methodology
Project
staff compiled and documented research on the health effects of biosolids. The starting point for this work was a
literature review commissioned by the Water Environment Association of Ontario
(WEAO), which was completed in April 2001.
The WEAO report looked at the full range of contaminants in biosolids
and identified which groups of contaminants should be the focus for further
study. These groups then became the
focus for the Apedaile/CH2M Hill investigation. In total, 168 articles were compiled and read for the final
report.
Project
staff also interviewed nine biosolids researchers/experts, representing
different views, to provide context to the published work and to discuss
emerging issues. The researchers were
asked about implications of their research for municipalities spreading
biosolids. Transcripts of these
interviews are included in the full report.
Best
Management Practices were developed for Ottawa’s program. During public consultation for the Biosolids
Management Plan Update in 2001, a recurring theme was lack of confidence in the
existing guidelines.
Lastly,
environmental health expert Dr. Donald Cole advised on the project from
beginning to end. He visited Ottawa in
March to meet with the Medical Officer of Health and members of the project
team for a full day to review scientific rationale for determining Best
Management Practices. Dr. Cole gave
regular feedback throughout the process.
An associate professor of community medicine/epidemiology in the Faculty
of Medicine at the University of Toronto, he has extensive experience in the
field of environmental health as a medical doctor, scientist, and educator.
All
tasks were completed during a three-month period from January to the end of
March 2002.
Scientific Review
The project team examined different kinds of studies
on the health effects of biosolids, providing a variety of perspectives.
Research ranged from epidemiological cohort studies (e.g. comparing the health
of exposed and unexposed farmers) to the fate of specific biosolids
contaminants such as estrogenic hormones.
The report identified the research challenges of
determining the potential health effects (if any) to biosolids, as in many
other areas of environmental epidemiology.
Specialists in the field range from engineers to microbiologists, all
studying different aspects of biosolids application. “The result is that none of the papers reviewed addressed all
components, given that the constituents of different forms of biosolids may
vary substantially, as do methods of application (and hence exposures) and
health outcomes of relevance (e.g. infection versus irritation),” the report
states. In general, few studies gave
consideration to exposures other than biosolids that might confound the
biosolids-health effects relationship.
Further, the group of relevant studies on exposure to biosolids included
both heterogeneous population (sewage treatment plant workers, neighbouring
application sites) and heterogeneous study designs”.
Still, it was encouraging to note that biosolids in
Ottawa are applied more cautiously than in other North American jurisdictions
where much of the research was done.
Disagreement among scientists was evident in the
scientific review. For instance, the
WEAO report recommended further investigation of several unregulated metals
such as silver, thallium and lead, but in an interview with the project team,
Dr. Rufus Chaney (U.S Department of Agriculture) argued that high applications
of these metals will have little effect on soil composition. “Until you have reason to believe that there
is a risk to humans from the highest transfer pathway, you shouldn’t be
regulating it,” he said. Other experts
are more cautious. Ellen Harrison of
the Cornell Waste Management Institute, speaking about a recommendation made by
her group regarding land application of sewage sludge stated, “It was a
cautionary statement. It did not say don’t do it, it simply said if you are
going to do it, make sure (you) get test results, apply clean sludges, more
conservative soil values”.
Most Best Management Practices listed in the report
exceed current provincial standards or create a new practice. The goal of implementing best practices is
to protect health, to adapt a more cautionary approach than what is suggested
in provincial guidelines, and to improve communication with the public.
These
goals will be realized by:
·
Limiting public
exposure of biosolids
·
Placing more
restrictions on biosolids use
·
Providing detailed
instructions on procedures
·
Improving testing,
monitoring and training
·
Implementing a
comprehensive approach
·
Better
information-sharing
Several of the proposals are already being practiced
in Ottawa and should continue. These include well monitoring and nearby
resident notification. Other proposals,
such as caution signs around fields, more detailed complaint protocols, and
rapid incorporation of biosolids into soil represent more significant changes
to the City’s program. If adapted,
these best practices would be considered among the most stringent in North
America.
Of
the 27 farm sites spread last year in Ottawa, there was one documented health
complaint – members of a family living close to a biosolids stockpile
complained of diarrhea, headaches, dry eyes and dry throat. After investigating the matter, Public
Health identified no health hazard. Results of the City’s well testing and
stool sampling were negative.
Nevertheless, the complaint did raise concerns about the proximity of
stockpiles to neighbouring residents.
The proposed Best Management Practices address two issues here. First, unlike provincial guidelines, the
Practices specify separation distances from stockpiles to residences and
population centres. Second, they
institute a formal complaint process.
Limiting Public Exposure
Current provincial guidelines restrict biosolids spreading to within 50-450 metres from a residential area. (A residential area is defined as seven or more adjacent residences on 1.5 acres maximum lots). However, the BMPs maintain a separation distance of at least 450 meters for residential areas and other places such as schools, multiunit residences, retirement homes and centres of employment. Separation from a well is at least 90 metres in the BMPs, whereas current provincial guidelines allow for a separation distance of 15-90 metres, depending on the well type. BMPs propose that stockpiles, which are not addressed in the province’s guidelines, should be located at least 450 m from an individual residence. Hauling trucks need to be inspected and tarped. Biosolids inadvertently tracked onto public roadways should be removed immediately.
Placing More Restrictions
According to the proposed best practices, farmers should wait at least one year after biosolids application before growing non-root vegetable crops, five years before growing root vegetable crops, and five years before using the land as pasture. The provincial guidelines are weaker, allowing for pastureland after only two to six months. The BMPs prohibit application in areas subjected to frequent flooding and during times of disruptive wind conditions – two problems not addressed by the provincial guidelines. Incorporating (mixing) biosolids into the soil should be done within two hours of application rather than allowing 24 hours.
The Best Management Practices explain how soil depth and field size should be measured, what should be included in a site plan. Protocols responding to complaints, well contamination, public health incidents, spills and violations are covered in the BMPs, but not addressed in the provincial guidelines.
While
not required by the Province, site inspection by a qualified party, independent
of the contractor, is included as a BMP.
Monitoring the quality of pre-application biosolids should be done every
two weeks, somewhat more frequently than what the Province suggests. The BMPs also require testing of wells
before and after biosolids application, and soil pH testing within four months
prior to spreading. The BMPs provide
direction on how and when to measure soil depth. Training of staff and contractors is also included.
A Comprehensive Approach
Controlling
pollutants entering the waste treatment plant is an important part of the
biosolids program. Two programs are
already in place - The City’s current “Take It Back” program for unused
medications, and continuing efforts to strengthen the Industrial Sewer Use
Control program.
Better Information Sharing
Currently,
the landowner signs an application form simply indicating consent. The BMP involves a more detailed consent,
indicating a full understanding of crop restrictions, waiting periods, site
plans and nutrient amounts. Where the
landowner differs from the farm operator, the farm operator must also sign the
consent. Under BMPs, residents within
450 metres of the spreading site are notified between two to eight weeks before
spreading. Information about the
biosolids program should be made easily available for public inspection, and
signs indicating the use of biosolids need to be posted around fields. None of
the above practices exists under provincial guidelines.
If
Council approves the above practices, the City’s biosolids land application
program will begin immediately by implementing all the health-related BMPs as
well as practices regarding separation distances and incorporation. BMPs already in place will continue. All efforts will be made for the remainder
of BMPs to be implemented within four to six weeks of Council approval.
RURAL IMPLICATIONS
The issue is of concern to all residents of Ottawa, but particularly to
those who live in rural areas. Rural residents live closest to lands applied
with biosolids, and farmers use biosolids as a fertilizer alternative for their
crops.
The
Biosolids Management Plan Update (2001) involved extensive public consultation,
giving Ottawa residents many opportunities to provide input. There were two open houses, followed by a
workshop and a public meeting, then an extended period of public input after
release of the plan, which was made available through client service centers
and rural libraries. The Biosolids
Management Plan Update Public Advisory Committee met six times. The Medical Officer of Health also met with
the community group Health Dangers of Urban Use of Pesticides (HDUUP) in Dec. 2001 to discuss the biosolids issue. Public
input received from the above sessions was considered in the preparation of
this report to Committee. Prescribed
time constraints did not allow for new consultations.
Ongoing
efforts are underway to better interact with the public to respond to the
community’s needs. Examples of these efforts
include development of an electronic registry for biosolids complaints that
will be made accessible to the public, and the initiation of a pilot Biosolids
Environmental Management System that incorporates significant public input.
The project methodology was presented to the Environmental Advisory
Committee on March 14. A presentation
scheduled for the Agricultural and Rural Affairs Advisory Committee on March 26
was cancelled on account of inclement weather.
FINANCIAL IMPLICATIONS
The Best Management
Practices recommended by the Medical Officer of Health, in consultation with
TUPW and other experts, will increase the program operating costs of the
Utilities Branch of TUPW. It is
expected that an additional $100,000 in operating costs will result in the
areas of enforcement, site selection procedures (investigation, assessment and
review), and documentation/information management. This amount was not identified in the 2002 operating budget, TUPW
will try to accommodate the increased cost.
TUPW will identify this amount as a 2003 budget pressure.
ATTACHMENTS
Document
1 – Executive Summary, Health Aspects of Biosolids Land Application
(Full
report on file with the City Clerk.)
TUPW
staff will move to implement all health-related BMPs immediately, as well as
practices regarding separation distances and incorporation. Every effort will be made to implement all
other BMPs within four to six weeks after spreading begins.
TUPW
staff will resume land application of biosolids with their contractors.
Health Aspects of Biosolids Land Application
Prepared for
City of Ottawa
March 2002
Prepared under the direction of the Medical Officer of Health by:
Erik Apedaile, P.Ag.
Environmental Management Services
1622 Pullen Ave
Ottawa, Ontario
K1G 0N7
CH2M HILL Canada Limited
1101 Prince of Wales Drive
Suite 330
Ottawa, Ontario
K2C 3W7
Dr. Donald Cole, M.D.
Department of Public Health Sciences
Faculty of Medicine
University of Toronto
12 Queen’s Park Crescent West
Toronto, Ontario
M5S 1A8
University
of Toronto
Department of Public Health Sciences
Faculty of Medicine, McMurrich Building
12 Queen’s Park Cres West
Toronto, Ontario M5S 1B8
Tel 416/946-7870
Fax 416/ 978-8299
donald.cole@utoronto.ca
1 April, 2002
Medical Officer of Health
City of Ottawa
495 Richmond Road
Ottawa, ON
|
Subject: |
Health Aspects of
Biosolids Land Application |
Dear Dr. Cushman:
Based on the information collected in the report “Health Aspects of Biosolids Land Application” (March 2002), as a qualified community medicine specialist and independent reviewer, I support your recommendation to continue with the practice of biosolids land application.
I am making this recommendation in the context of the implementation of the Best Management Practices by the City of Ottawa.
Yours truly,
Dr.
Donald Cole, M.D., M.Sc., FRCPC
Associate Professor
Built
in 1961, the Robert O. Pickard Environmental Centre (ROPEC) is one of the
largest wastewater treatment facilities in Canada. The facility treats an
average capacity of 545 million litres of wastewater per day, with a peak
capacity of 1,362 ml/d. It produces about 30 dry tonnes of dewatered biosolids
(approximately 4 truck loads) per day.
In
August 2000, the City initiated its five-year update of the Biosolid Management
Plan. The update included a
comprehensive review of current practices, identification and assessment of
alternatives, and extensive public consultation. The update was based on the
premise that the Province of Ontario is responsible for regulating biosolids
for protecting public health.
In
December 2001, while accepting the recommendations of the Biosolids Management
Plan Update, Ottawa City Council directed the Medical Officer of Health (MOH)
to review the safety of land-applying biosolids and to develop application
standards that meet or exceed the current provincial standards. Specifically,
the MOH was directed to take the following actions:
·
Retain the necessary experts to conduct a
scientific review of the safety of spreading biosolids
·
Recommend interim best management practices for
the City’s biosolids management program
·
Present the expert analysis and the new
standards to the Environmental Services Committee
The
biosolids land application program for Ottawa was suspended pending the outcome
of the MOH’s recommendation.
In
response to Council’s directive, the MOH retained Apedaile Environmental and
CH2M HILL Canada Limited to undertake the following:
Task 1: Search, collect, and summarize the
current literature on health aspects of land-applying anaerobically digested,
dewatered biosolids
Task 2: Interview specialists to provide
scientific and regulatory perspectives on current work in the biosolids area
Task 3: Develop interim best-management practices
based on current practices, research, and experience
The
Medical Officer of Health elected to undertake a 4th Task:
Task 4: The City was to retain a qualified
third-party health specialist for evaluating the information and providing feed
back to the MOH
The
project team recognizes that the issue of human health related to land
application of biosolids is of general
public concern and, while there is a great deal of literature related to this
topic, there also is much disagreement.
Every
attempt has been made to reflect views from across the spectrum on this issue.
The intent of this report was to identify the research and information
available for the sole use of the Medical Officer of Health in his
determination regarding the safety of land application of biosolids for the
City of Ottawa. The opinions and views
expressed in the literature and in interviews are those of the authors and
interviewees and not of the City or its consultants.
The
project focused on collecting health-related information bearing on the type of
biosolids generated at the Pickard Centre and on its land-application
practices. The project team collected scientific literature and abstracts, and
spoke with a series of key contacts and specialists in the field of biosolids
management related to human health issues.
During
the review two key difficulties emerged:
1.
There is a lack of
multi-disciplinary research and biosolids-specific medical data
2.
The vast body of
research related to biosolids and land application required a narrowed field of
focus given the time constraints of this project
To
narrow its focus, the team used a recently published review of literature and
stakeholder groups as a starting point for collecting scientific literature.
This review, Fate and Significance of Selected Contaminants in Sewage
Biosolids Applied to Agricultural Land Through Literature Review and
Consultation with Stakeholder Groups (April
2001) was commissioned by the Water Environment Association of Ontario (WEAO).
The WEAO review examined a broad range of contaminants and divided them into
two groups:
Group
I contaminants: These have sufficient, credible
scientific evidence to demonstrate that they are not a concern in sewage
biosolids
Group
II contaminants: These do not have sufficient, credible
scientific evidence to demonstrate they are not a concern in sewage biosolids
Therefore, the team
focused on the Group II contaminants, namely:
·
Pathogens
·
Unregulated metals
·
Estrogenic hormones and pharmaceutically active
compounds
The team also explored emerging issues (PBDEs and health effects related to odours) and health studies. An overview of the literature in these areas is presented in this review, however, as the WEAO studied noted, all of these areas are in need of further research. The review team developed a database of the literature considered in preparing this report, and collected and collated hard copies of the majority of the literature.
Key
contacts and specialists were selected to represent the breadth of scientific
and regulatory opinion on health aspects of biosolids land application. People
involved in developing and implementing regulations in the United States and
Canada, as well as people from research institutions who have been critical of
the regulations were selected for interviews. In addition, published
researchers were contacted for context and clarification of their published
work. The ability to interview key contacts and specialists was limited by time
and budget.
The
literature and interviews with key contacts and specialists assisted in the
development of a series of interim best management practices (BMPs). One
premise used to develop the interim BMPs was that limiting public contact with
biosolids may mitigate potential public health risks from exposure. In addition, the BMPs sought to respond to
community concerns specific to the City of Ottawa identified during the
Biosolids Management Plan Update public consultation process. The interim BMPs cover all aspects of the
land application program from selecting application sites, the approval
process, and spreading activities, to record keeping and auditing. Emergency
measures and at-source controls also are addressed.
Finally,
in accordance with Task 4, a qualified and independent third party, Dr. Donald
Cole, MD, an expert in community medicine with the University of Toronto, was
retained directly by the Medical Officer of Health. Dr. Cole assessed the information collected in Tasks 1-3 and provided
feedback to the MOH in his determination regarding the safety of biosolids land
application.