Microbiological contamination of groundwater.pdf


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Ketty Balthazard-Accou, Evens Emmanuel, Momar Diouf, Patrice Agnamey

The scenario highlights the existence of a dumpsite
In order to avoid initially conducting a major campaign
of sampling in different emission sources of oocysts
where leachates are not collected or treated. They
toward the groundwater, we have introduced in the
are in direct contact with the soil and they follow
analysis plan an initial step consisting in working only
the transfer mechanisms toward the groundwater.
on water from the groundwater and that is used by
Latrines and septic tanks, discharging into the
people. This phase aims at detecting Cryptosporidium
unsaturated geological matrix area, are also noted.
oocysts during the two rainy seasons of the year and
Other utilities such as boreholes and wells feeding a
ingestion of water from the aquifer or surface water. The
very usethe
of the
aquiferresults
for water
supply, taken
in from
comparing
different
obtained
in water
family or group of families with water, an urban water
the particular context of the scenario observed, canthe
be an
important
source
of
distribution
of
infectious
groundwater for pathogen selected within the
supply andwaterborne
an individual
sanitation
network
diseases
in the study
area. are also
number zero to 100 liters of water.
presented in this scenario (Figure 1).
In order to avoid initially conducting a major campaign
of number
samplingofinoocysts
differentless
emission
For any
than 1sources
per 100ofliters of
The scenario reproduces the supply mode of drinking
oocysts toward the groundwater, we have introduced
in the
analysisforplan
an initial
step consisting
in
water
intended
human
consumption,
the flowchart
water and working
wastewater
Les Cayes.
only onmanagement
water from theingroundwater
and that
is used bythe
people.
This of
phase
aims at detecting
showcases
absence
Cryptosporidium,
which in
PercolationCryptosporidium
of leachates from
uncontrolled
oocysts
during thedischarge,
two rainy seasons
the year
comparing
the different results
turnofjustifies
theand
absence
of contamination,
thus there
the hydraulic
operation
of
the
effluents
generated
obtained in water from the groundwater
for by
pathogen
selected
within
thefor
number
zero to 100 However,
liters of this
is no
hazard
(risk)
the population.
latrines and
septic tanks, contamination of surface
water.
type of procedure recommends the implementation of
water and the interactions between these aquatic
a microbiological
surveillance
consisting
of
For any number of oocysts less than 1 per 100 liters
of water intended
for human program
consumption,
the
ecosystems
and
groundwater
reflect
the
existence
periodic
characterization
of
Cryptosporidium
oocysts
flowchart showcases the absence of Cryptosporidium, which in turn justifies the absence of
of a risk tocontamination,
human health
may
from(risk)
the for inthethepopulation.
water from
the groundwater.
In contrast, for
thusthat
there
is result
no hazard
However,
this type of procedure
ingestion of
water
from
the
aquifer
or
surface
water.
any
number
of
oocysts
greater
than
or
recommends the implementation of a microbiological surveillance program consisting of equal
periodicto 1 per
The very use
of the aquifer
water supply,oocysts
taken in
liters
water
intended for
human consumption,
characterization
of for
Cryptosporidium
in the100
water
fromof the
groundwater.
In contrast,
for any
recommends
next steps
the particular
context
of thegreater
scenario
number
of oocysts
than observed,
or equal to 1can
per 100the
litersapproach
of water intended
for humanthe
consumption,
the of the
approach
recommends
the next steps
of the evaluation
of biological
to consumer
(Fig .2).
evaluation
ofrisks
biological
riskshealth
to consumer
health
be an important
source
of distribution
of infectious
(Figure
2).
waterborne diseases in the study area.

Figure
2. 2:
Flowchart
developed
implementation
biological
assessment
Figure
Flowchart
developedforforthe
the
implementationofofthe
the
biologicalrisk
risk
assessmentdue
duetoto
presence of Cryptosporidium
oocysts
the presence ofthe
Cryptosporidium
oocysts.
2.3. Identification
of danger
2.3. Identification
of danger

their feces laden with bacteria, viruses and other
parasites into the groundwater; ii) discharge of urban
For the For
microbiological
assessment
of
the microbiologicalrisk
risk assessment
of Cryptosporidium
in drinking
water,
an approach
basedtreatment;
on the
into rivers
without
any prior
iii)
Cryptosporidium
drinking
water, anfactors
approach
based for effluents
analysisin of
the numerous
responsible
potential exposure of Les Cayes groundwater to
the existence of latrines and septic tanks equipped
on the analysis
of the
numerous
factors
responsible
biological
contaminants
has
been developed.
Among these factors : i) cattles wandering freely in the city
a high-risk
flood
for potential
exposure
of Les Cayes
to of with
leading
to a permanent
and groundwater
significant spread
their infiltration
feces ladenwells
with in
bacteria,
viruses
andarea;
other iv) the
disposal
of
sludge
from
latrines
and
septic
on
biological contaminants
has
been developed.
Among
parasites into the
groundwater;
ii) discharge
of urban effluents into rivers without any prior treatment; tanks
iii)
the
floor
of
an
alluvial
formation;
v)
the
existence
of
these factors
: i) cattles
in theequipped
city
the existence
of wandering
latrines and freely
septic tanks
with infiltration wells in a high-risk flood area; iv) the
illegal landfills in an alluvial formation with unprotected
leading to a permanent and significant spread of
54

Aqua-LAC - Vol. 9 - Nº. 1 - Mar. 2017