Industrial and Environmental Risk Clusters in the Gironde Region

Project Overview

This project examines the spatial distribution, concentration, and cumulative nature of industrial and environmental risks in the Gironde region. The analysis focuses on regulated industrial facilities (ICPE), pollutant-emitting installations (IREP), hazardous-material pipelines, and former industrial sites in order to identify zones of heightened environmental pressure.

Research Goals

The objectives of this research are to:

  • Identify and visualise clusters of industrial and environmental risk
  • Highlight communes with high concentrations of hazardous activities
  • Examine spatial relationships between industrial facilities and infrastructure
  • Assess whether higher facility density is associated with greater environmental discharges

Research Questions

The project addresses the following four research questions:

1. Spatial Distribution

How are industrial and environmental risk facilities (ICPE, IREP, and pipelines) distributed across the Gironde region?

2. Clustering and Proximity

Do pollutant-emitting facilities cluster spatially within existing industrial zones and infrastructure corridors?

3. Historical Overlap

Is there a spatial overlap between current pollutant-emitting sites and former industrial activity?

4. Risk Density and Discharges

Do communes with higher densities of ICPE and IREP facilities also report greater environmental discharges?

Research Data

This study relies exclusively on publicly available open-data sources related to industrial risk and environmental infrastructure in the Bordeaux–Gironde region.

Former Industrial Sites (CASIAS)

Geolocated records of former or potentially contaminated industrial sites.
Source: Bordeaux Métropole Open Data
https://datahub.bordeaux-metropole.fr/

Hazardous-Material Pipelines

Spatial data describing underground and above-ground pipelines transporting hazardous fluids.
Source: Bordeaux Métropole Open Data
https://datahub.bordeaux-metropole.fr/

Pollutant-Emitting Industrial Facilities (ICPE and IREP)

National datasets of regulated industrial installations reporting emissions to air, water, or soil.
Source: Géorisques (France)
https://www.georisques.gouv.fr/

Administrative Boundaries

Departmental and communal boundaries used for spatial aggregation and visualisation.
Source: GADM
https://geodata.ucdavis.edu/gadm/

Datasets Used

  • Former industrial sites (historical activity)
  • Hazardous-material pipelines (linear infrastructure)
  • ICPE facilities (regulated industrial installations)
  • IREP facilities (pollutant-emitting installations)

Data Processing and Methods

The analysis includes:

  • Harmonisation of all spatial datasets to Lambert-93 (EPSG:2154)
  • Mapping of all industrial risk layers on a common spatial reference
  • Kernel Density Estimation (KDE) using a 1 km bandwidth to identify industrial hotspots
  • Aggregation of ICPE and IREP facility counts at the commune level
  • Comparison of facility density with total reported environmental discharges

Data Visualisation Overview

The results are presented through five complementary visualisations, each addressing a specific analytical dimension:

  1. Base Map of Industrial Risks
    Displays ICPE facilities, pollutant-emitting installations, former industrial sites, and hazardous-material pipelines to illustrate the overall spatial distribution of risk sources.

  2. Industrial Activity Hotspot Map
    A kernel density map identifying areas of concentrated industrial activity based on the cumulative presence of risk-related installations.

  3. Density versus Discharge Scatter Plot
    Examines the relationship between ICPE + IREP facility density and total reported environmental discharges at the commune level.

  4. Spatial Distribution of Industrial Risk Density
    A choropleth map showing ICPE + IREP facility density per square kilometre by commune, highlighting spatial disparities in industrial concentration.

  5. Cumulative Concentration of Environmental Discharges
    A cumulative line graph illustrating how total environmental discharges accumulate across communes ranked by increasing industrial risk density.

Together, these visualisations provide both spatial and statistical perspectives on industrial risk and environmental pressure.

Question 1: Spatial Distribution

Industrial and environmental risk facilities in the Gironde region exhibit a strongly clustered spatial pattern rather than a uniform distribution.

The base map shows that the Bordeaux metropolitan area forms the dominant industrial core of the region. ICPE installations, pollutant-emitting facilities, former industrial sites, and pipelines are densely concentrated in and around Bordeaux, reflecting its historical role as a major industrial and logistical centre.

Outside this metropolitan core, industrial facilities become increasingly sparse and fragmented. Rural and peripheral communes contain fewer sites and contribute less to overall regional risk. Pipelines generally follow a north–south alignment and intersect the most industrialised zones, reinforcing existing spatial concentrations rather than creating new ones.

Question 2: Historical Overlap

Overlay analysis reveals substantial spatial overlap between current pollutant-emitting installations and former industrial sites.

This overlap is most pronounced in the Bordeaux metropolitan area, where historical industrial land use has persisted through continued operation or redevelopment. Areas with high historical industrial density also tend to exhibit high present-day industrial intensity.

Former industrial sites located outside the metropolitan core are more dispersed and generally associated with lower current emission densities, suggesting partial industrial decline or land-use transition. From a risk perspective, this overlap implies cumulative environmental pressure, where historical contamination may coexist with ongoing emissions.

Question 3: Risk Density and Environmental Discharges

The relationship between industrial concentration and environmental impact is examined using both a scatter plot and a cumulative concentration graph.

The scatter plot relates ICPE + IREP facility density per square kilometre to total reported environmental discharges, with both variables displayed on logarithmic scales. A clear positive association is observed: communes with higher facility densities generally report higher total emissions. High-density communes cluster in the upper-right portion of the plot, indicating both concentrated industrial activity and elevated environmental burden.

However, variability around the regression line indicates that facility density alone does not fully explain emission levels. Some moderately dense communes report disproportionately high discharges due to the presence of large or highly polluting installations, while some high-density communes exhibit comparatively lower emissions, potentially reflecting cleaner technologies or sectoral differences.

The cumulative concentration graph further shows that a relatively small proportion of communes accounts for a large share of total environmental discharges. This confirms that environmental pressure in Gironde is highly concentrated rather than evenly distributed.

Integrated Interpretation

Taken together, the five visualisations demonstrate that industrial and environmental risk in the Gironde region is spatially concentrated, historically structured, and unevenly distributed.

Risk is greatest where industrial density, history land use, and emission intensity intersect. These findings highlight that environmental exposure is cumulative and place-based rather than uniformly distributed, supporting the need for targeted and spatially differentiated environmental risk management.