Health outcomes in populations living close to landfill sites

Lars Jarup, David Briggs,

Cornelis de Hoogh, Christopher Hurt,

Tina Kold Jensen, Sara Morris,

Jon Wakefield and Paul Elliott

The Small Area Health Statistics Unit (SAHSU), Department of Epidemiology and Public Health, Imperial College

Modelling exposures from landfill sites: Methods and issues

Cornelis de Hoogh, David Briggs, Christopher Hurt,

Lars Jarup and Paul Elliott

The Small Area Health Statistics Unit (SAHSU), Department of Epidemiology and Public Health, Imperial College

Background Excess risk of adverse birth outcomes and certain

cancers have been reported, primarily in the USA (hazardous waste sites) Low birthweight (Goldberg et al, 1995; Kharazzi et al, 1997;

Berry and Bove, 1998) Stillbirth (Kharazzi et al, 1997) Congenital anomalies (Geschwind et al, 1992, Croen et al, 1997) Mallin, 1980 (bladder cancer) Goldberg et al, 1995 (several cancers including liver) Willams et al, 1998 (brain cancer)

Background Two recent European and UK studies

EUROHAZCON (1998) neural tube, cardiac and vascular defects decrease in risk by distance, BUT several landfills in “reference area” not

accounted for

Nant-y-Gwyddon (2000) increased risk of malformations also before

site opening

Aims Primary objectives: to test the hypotheses

that living near a landfill site is associated with excess risk of congenital anomalies, stillbirth, low birthweight or very low birthweight

Secondary objective: to test the hypothesis that living near a landfill site is associated with an excess risk of certain cancers

Industrial emissions

Vehicle emission

s

Mineral dusts

Solid wast

eWaste handlin

g

Atmospheric dispersion

Animal/bird dispersion

Drainage/ Leaching

Runoff

Gaseous emission

s

Aqueous emission

s

Soil contaminatio

n

Dermal

contact

Ingestion

Water pollution

Inhalation

Prior land use

Excavation

Waste disposa

l

Capping/

restoration

After-

use

Plant uptake

Click for larger picture

Analyses Effects of socio-economic status and other

explanatory variables urban-rural differences

maternal age (for abdominal wall defects)

Landfill sites classified as receiving ‘special’ (hazardous) or ‘non-special’ waste

Periods before and after opening of landfill sites Poisson regression

99% confidence intervals

Study area

“Exposed” population defined as living within 2 km from a landfill site 80% of the national population

Likely limit of dispersion (WHO 2000) 1 - 2 km depending on pathway

Study period

DATA ISSUES

Landfill data

• Point locations only

• Locational errors in point co-ordinates (< 1000 metres+)

• Landfill sites evolve/change over time

• Incomplete data on opening/closing dates, waste types

• Inconsistencies in reported operating dates and waste types

Health/denominator data

• Reporting errors and inconsistencies

• Changes in coding

• Socio-economic data at ED level only (1991 census)

• Postcodes = points to represent areas (<1 km + approximation inrural area)

• Errors in reported postcodes (<100 metres +)

Nr of landfill sites per 5 x 5 km21

2

3 - 4

5 - 8

9 - 68

Nr of landfill sites per 5 x 5 km21

2

3 - 4

5 - 8

9 - 68

Click for larger picture

6 Exclude

2 Operatingyes

no

no

no

no

Is the landfill open at this moment?

Was the landfill site closed earlier dur ing the study period?

Was the landfill site closed beforethe start of the study period?

Was the landfill site opened later dur ing the study period?

Was the landfill site opened after the end of the study period?

Start postcode

3 Closedyes

4 Excludeyes

5 Beforeyes

yes

Has there ever been a landfill site within buffer distance??

yes

no 1 Reference

Resi dual postcodes 8 ExcludeResidual postcode

7 Exclude

no

Incomplete data yes

6 Exclude

2 Operatingyes

no

no

no

no

Is the landfill open at this moment?

Was the landfill site closed earlier dur ing the study period?

Was the landfill site closed beforethe start of the study period?

Was the landfill site opened later dur ing the study period?

Was the landfill site opened after the end of the study period?

Start postcode

3 Closedyes

4 Excludeyes

5 Beforeyes

yes

Has there ever been a landfill site within buffer distance??

yes

no 1 Reference

Resi dual postcodes 8 ExcludeResidual postcode

7 Exclude

no

Incomplete data yes

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Landfills data 19,196 sites in Great Britain

9,631 sites were excluded closed before 1982 or opened after 1997

inadequate data

9,565 sites included in study 774 special waste sites

7,803 non-special waste sites

19,196 landfill sites x 1.6 million postcodes x 16 years x 2 lag periods = 1011 buffering operations!

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

0 - 9 10 - 19 20 - 29 30 - 39 40 - 49 50 - 59 60 - 69 70 - 79 80 - 89 90 - 100

Pe rcentage Urban

Ra

tio

: e

xp

os

ed

/un

ex

po

se

d

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

< 0 0 - 1 1 - 2 2 - 3 3 - 4 4 - 5 5 - 6 6 - 7 > 7

Air quality index (NOx, PM10, SO2 and Benzene)

Ra

tio

of

ex

po

se

d/u

ne

xp

os

ed

po

pu

lati

on

Click for larger picture

31.533.235.2Excluded

24.432.443.1Unexposed

35.334.230.4Exposed

Most deprived

Intermediate

Most affluent

Exposure by socio-economic status

Results - congenital anomalies

Results - stillbirth and birth weights

Results - stillbirth and birth weights

Results – cancers

Click for larger picture

Discussion The largest study to report on the

possible association between residence near landfill and health outcomes

Deprivation adjustment may incompletely account for individual-level characteristics associated with risk of congenital anomalies and cancers

Need to take account of the complexity of the system, and data limitations, in using GIS for exposure assessment

80% of population live within 2km of a landfill site

No causal mechanisms currently available to explain our findings

Alternative explanations possible data artefacts residual confounding

Further understanding of the potential toxicity of landfill emissions and possible exposure pathways is needed in order to help interpret the epidemiological findings

Conclusion

References Elliott P, Briggs D, Morris S, de Hoogh C,

Kold Jensen T, Maitland I, Richardson S, Wakefield J, Jarup L. Risk of adverse birth outcomes in populations living near landfill sites. BMJ 2001;323:363-8.

http://www.bmj.com/ http://www.doh.gov.uk/whatsnew/index.html