3.4.2.2 Waste Pollution
The United Nations Conference on Environment and Development
(1992) pointed out that rapid urbanization and demographic concentration have
shocking implications for shelter and sanitation, and especially the disposal
of wastes. Waste is responsible for the transmission of agents of infectious
disease from human and animal excreta, the breeding of disease vectors, and
exposure to toxic chemicals in human and animal excreta (WHO 2006).
Port-au-Prince is the perfect example of this statement. Waste production and
disposal outweigh the institutional, structural, and managerial capacity of
institutions in charge. Two problems arise from waste collection in
Port-au-Prince. First, the collection of waste is absent in slums due to
inaccessibility to the narrow streets and alleys (World Bank 2005). Second,
where it occurs, waste collection is not reliable. For instance, a lack of
fuel or money to buy it, broken or lack of vehicles, and employees' strikes
may cause waste to store up for days, even weeks, spreading all over the
streets, blocking vehicle transport, and giving off offensive smells. In fact
the garbage is fully exposed to the air and the wind, along with mosquitoes,
cockroaches, and rodents facilitating the spatial propagation of the
pollutants. No less shocking is the presence of hogs in some neighborhoods
streets where waste is dumped.
Though these factors could not be accounted in the determination
of waste incidence, we assumed that the spatial extent of this hazard is
inversely proportional to the proximity to the sources. The waste collection
network was digitized based on information gathered from SMCRS (Service
Metropolitain de Collecte des Résidus Solides). The geometry of the
network being linear, we had to consider whether the hazard manifests across
the network or in dumping at specific points. However, no such information was
available: the collection locations may change at any time and, in spite of the
presence of some established posts along the network, there is no way to
control the emergence of new unplanned ones. After calculating the Euclidean
distance of the waste network feature, the resulting raster was divided into 4
classes from 0 to 400 meters with increment of 100 between each threshold.
To take into consideration the inaccessibility of some areas to
waste collection, neighborhoods located at least 400 meters from the waste
collection network were also integrated into the model. In low-to-medium
residential areas where mostly people of middle economic class or above reside,
some private services ensure the pick up of garbage. But people living in
high-to-extremely high density housing neighborhoods may be struggling to get
rid of waste, may have used non-hygienic or non-conventional ways to eliminate
their garbage (for instance burning, or depositing it in the streets when it
rains, or dumping it into the channels) , and consequently create a hazard for
human's health. Those areas away from the network were given values in
reference to the housing density. Then, both distances less than 400 meters
and greater 400 meters were summed.
Regarding the sanitation aspect of the neighborhoods, it would
not be reasonable to assume that the waste network conditions are uniform
everywhere. For instance, in areas involved with intensive commercial
activities like informal markets places, waste production is far much greater
than in areas with little activity. The waste network at La Saline does not
weigh against Lalue's circuit. This consists of a different aspect influencing
waste accumulation and conditions. Based on this evidence a raster that stands
for waste conditions was created and was integrated into the waste factor
determination.
Furthermore, elevation was believed to play a role in
neighborhoods' exposure to waste effects. On one hand, waste from upslope is
carried down by wastewater from the canals and by runoff; on the other hand, in
the absence of an efficient collection system, waste accumulates in lower
elevation and is mixed with water from artificial ponds and obstructed canals.
The same rationale illustrated for the pollution from traffic vehicle may be
also true for waste: better air circulation in higher elevation acts as barrier
to attenuate the pollution's impact of the garbage.
The different factors were aggregated using weights of 0.5, 0.3
and 0.2 for distance from waste collection network, conditions, and elevation
respectively. Once again those weights were personally chosen since I could
not access any example in the literature review for the study area. The result
was standardized to values comprised from 1 to 4 as displayed in Table 2.
Waste Risks = 0.5*Distance + 0.3*(Network conditions) +
0.2*Elevation
Table 2: Pollution from
Waste - Risk Levels
|
Levels
|
Low
|
Moderate
|
High
|
Very High
|
|
Range of values
|
0 - 1
|
1 - 2
|
2 - 3
|
3 - 4
|
|
Reclassified values
|
1
|
2
|
3
|
4
|
| 
