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Using Pollutant Release and Transfer Register
data for environmental health research
Hackett,
1
C. ;
Campbell,
1
S. ;
Wine,
1
O. ;
Osornio-Vargas,
1
A.
1. Faculty of Medicine and Dentistry, University of Alberta
Introduction
Research Methods
Discussion
Broad searches of the published literature were
performed using “PRTR” and related search terms in
multiple databases of scientific literature as well as
in Canadian Newsstand. Results were included if
they matched one of the three following criteria:
In reviewing the publication record around PRTR
data, several trends can be observed. Few articles
were published until 13 years after the release of the
first set of US TRI data. A greater lag was seen for
health studies, which used more complex methods.
The use of Canada’s NPRI may be hindered by a
similar time lag, as the scientific community
develops methods to use the data and as reporting
requirements and accuracy of reporting stabilize.
The challenges to the use of PRTR data in the
Canadian context may be better understood by
analyzing the use of other nations’ PRTR data.
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Pollutant Release and Transfer Registers (PRTRs) are
national databases of chemical releases reported by
industry to governments. The importance of
pollutants to health is well documented, however
the use of PRTR data to study relationships between
health outcomes and pollution has not been
evaluated. A preliminary literature search found
few published studies that used data from the
Canadian PRTR. Understanding past uses of PRTR
data is important in the evaluation of their
applicability to future health studies.
– Second level
1. Peer-reviewed studies that investigated the
relationship between PRTR data and health
outcome data.
2. Peer-reviewed studies that used PRTR data in
other ways.
3. Canadian media articles referring to the use of
PRTR data.
• Third level
Objectives:
1. To investigate how PRTR data has been used to
date by the scientific community, and
2. To review the challenges to the use of PRTR data
for future Canadian environmental health
research.
– Fourth level
» Fifth level
Many nations’ PRTRs were represented in the literature
search, including Australia, Canada, Japan, Spain, the UK
and the US, but the largest volume related to the United
States’ Toxics Release Inventory (TRI). The literature
search identified 41 health studies, 139 studies using
PRTR data in other ways, and 203 media articles
referencing use of Canada’s NPRI data, of which few
referenced scientific studies.
Country
United States
Canada
Name
Toxics Release
Inventory
To inform
communities about
toxic chemical releases
To support informed
decision-making by
industry, government,
non-governmental
organizations and the
public
1987
682
National Pollutant
Release Inventory
To improve public
understanding
First Data
Chemicals
Tracked (2010)
Health
35
Studies
Other Studies 95
To identify pollution
prevention priorities,
the assessment and
risk management of
chemicals, and air
quality modelling
1993
346
0
A variety of limitations, both in the data and in study
design are apparent in the studies.
30
25
20
15
10
5
0
Both
Location
Volume
Containment
Buffer
Decay
Lags between exposure and health effects were
addressed in some designs by studying fetal and
child health. Some studies addressed the lack of a
toxicity standard by using a variety of toxicityweighting systems. A limitation of many of the
health studies was the use of location or total
volume, neither of which is an accurate proxy for
toxic exposure or potency.
It is difficult to use topography, meteorology and
release rates to model chemical dispersion and
therefore exposure to pollution. The literature
revealed three main methods of studying spatial
associations of pollution and health outcomes, each
with its own limitations. It may be important to
address this in study design by using multiple
methods.
Conclusion
Method of Correlation
Figure 2: Spatial correlation methods used in studies of health
data, divided into the type of PRTR data used
The use of PRTR data in environmental health
research hinges on:
17
Table 1: Comparison of US and Canadian Pollutant Release and
Transfer Registers (PRTRs)
Number of Articles
-
Health data studied included cancer incidence,
population mortality, and birth defects. Most designs
used a containment method, which related health data
and the number of facilities or the volumes of pollutants
released in defined areas. Buffer methods assumed a
uniform exposure in rings around facilities, and decay
methods modeled exposure inversely related to distance
from facilities. 68%, 50% and 100% of the studies using
a containment, buffer and distance decay method,
respectively, found a positive correlation between
pollutant release and negative health outcomes.
Number of Studies
Results
Purpose
Specific data were extracted from each article. Only
articles written in English were included.
One of the greatest challenges in the use of PRTR
data is the limitations of the data itself. Though
PRTRs often lack data from smaller emitters, and
industry may report inaccurately, it is often the
most comprehensive national data available. No
study considered all identified limitations. Some of
the studies addressed some of the limitations
through study design, though this increased the
complexity of the studies and made conclusions
more difficult. Conclusions about the relationship
between health and pollution were also made
difficult due to potential confounding demographic
variables.
90
80
70
60
50
40
30
20
10
0
TRI
NPRI
Year
Figure 1: Total number of articles published using US TRI data
Limitations Identified
Imputable to PRTR data
Lack of non-threshold
emissions reporting (35)
Change in reporting
requirements over time (30)
Estimation errors and
assumptions in data reporting
(28)
Does not track all chemicals in
use (24)
Lack of mobile and/or area
sources (19)
Underreporting of emissions
(19)
Limitations Identified
Imputable to Study Design
Confounding variables (63)
No dispersion modelling to
estimate exposure (50)
Lack of toxicity standard (49)
Aggregation of population
data and exposure (20)
Modified Areal Unit Problem
(14)
Lag time between exposure
and health effects (14)
Table 2: Limitations identified in studies using PRTR data
1. Acknowledgement of the limits of the data,
2. Evaluation of exposure to chemicals, and
3. Correlation between chemical exposure and
health outcome data.
A review of the literature using Pollutant Release
and Transfer Register data revealed that the
scientific community has
found methods to investigate
associations between health
outcomes and pollution.
Though PRTR data is the
most complete pollutant data
available, the limitations of
the data present study design
challenges for environmental
health research.
Associated Press Images,
Image ID: 090110020006
Acknowledgements
Funding for this project was generously provided by the University of Alberta Office of the Provost and VP (Academic) and from an Emerging Research Team Grant administered
jointly by the University of Alberta Faculty of Medicine & Dentistry and Alberta Health Services, Edmonton Region.