Transcript
Microbial risk assessment due to municipal solid waste dumps
Vijaya Kiran Mentey, Nishith Desai,
Saifi Izhar(Mentored by: Mira Olson, Rebecca Ives)
Map of Hyderabad
Share of Municipal Employees: 60%
PPP Model: 40% Dumping ground: 340
Acres Distance from
Hyderabad: About 30 Kms
Process of garbage Generation: Street Sweeping & House hold garbage put into containers
Process of garbage Lifting: Using bare hands
Transportation- Loading the truck- No Gloves, No masks - Open transport
COMPOSITION OF GARBAGE Needles, syringes, used condoms, saline
bottles, soiled gloves and other hospital wastes
Contains human excreta, and dead animals Food either decomposed or putrefied Luxury waste such as paper, cardboard,
plastic and heavier organic materials. Hazardous materials such as tube lights, dry
battery cells , nail polish remover, blades, sprays and other miscellaneous items
Why Rag pickers are vulnerable They work, eat, sleep in the vicinity of garbage
dumps. Include infants, young children, women, child -
bearing age and seniors Children are particularly vulnerable to toxins They do not use safety gear such as gloves,
face masks, gum boots etc Collect material from burning garbage – leading
to burns Most of them are illiterate and in need for
employment
Who are at risk Rag pickers Municipal employees engaged in garbage
lifting Population living close to a waste dump
Water supply is contaminated either due to waste dumping or leakage from landfill sites.
They inhale fumes from burning of garbage
HAZARD IDENTIFICATION Based on kind of microorganisms isolated from garbage Prevelant diseases/ ailments/ infections amongst the
rag pickers Based on various surveys, the following were identified
as potential ailments: Respiratory ailments Diarrhea Asthma Pneumonia Dysentery Tuberculosis Skin disease, etc. wounds
HAZARD IDENTIFICATION We also wanted to compare the health risks
for Workers employed by government Daily workers
As well as, the health risk between men and women.
Biological indicators selected for the study
•Pathogenic E.coli
•SalmonellaBACTERIA
•Rhinovirus•RVSVIRUS
EXPOSURE ASSESSMENT
PATHWAYS
Oro-fecal
Ingestion
Touch
Nasal
EXPOSURE ASSESSMENT Dose (ingestion) = (initial microbial load per
100 mg per hour) x (no. of hours exposed) Dose (Hand Transfer) = (Hand Transfer) x
(Mouth Transfer) Where, Hand Transfer = (Initial microbial
concentration on object) x 0.1% Mouth Transfer = (Hand Transfer) x 36%
Dose (nasal) = (initial microbial load) x (Rate of inhalation- m3/ hr) x (no of hours exposed)
DOSE RESPONSE
MICROORGANISM
CONCENTRATIONDOSE VALUE
RISK OF INFECTION RISK OF ILLNESS
MODELLING EQUATIONS
Biological Indicator Models used
alpha N=50
K value References:
Salmonella sp. Beta Poisson 1.75E-01 1.11E+06
Hornick RB, et al. (1966), Hornick RB, et al. (1970)
E. coli O157:H7 Beta Poisson 1.55E-01 2.11E+06
Cornick and Helgerson (2004)
Rhino virus Exponential
1.00Hendley et al., 1972
RSV Exponential 9.98E-05Hall and et al., 1981
Assumptions for point estimates Assumption 1: Initial concentration of viruses in Garbage
was unknown, assumed as 1 PFU/g (Literature cites presence of 10^4 PFU/g of MS2. thus assuming, 1:10,000 dilution for presence of pathogenic viruses to indicator viruses, the assumed initial concentrations were calculated as 1 PFU/g)
Concentration of viruses in air through garbage: 1 log lesser than the concentration in garbage.
Simplified Assumptions: probabilities for bacterial and viral infections were assigned based on the basis of a survey of rag pickers (N=275). The probabilities of infection were assumed to be same for all age group and sex due to non-availability of data however the values may vary for the same. Probability for bacterial infection rate was 0.70. The probability for viral infections was 0.64
Touch transfer: Garbage to hand (0.1%), Hand to mouth (36%)
Total Working hrs:
Groups
Age Biological IndicatorsRoute of entry:
Type of transfer
Conc present in Garbage: (CFU/g; PFU/g, PFU/m3)
Dose value
Risk of infection (r1)
risk of infection(r2)
Risk of Illness
1-r(n)Cumulative risk
Cumulative risk for Bacteria/ Virus
Cumulative Risk of Illness for Bacteria/ Virus
Government 6hr
ALL all age
BACTERIA
Salmonella
Oro-fecal
ingestion 1.52E+063.80E+0
41.63E-01
0.1140598
8.37E-010.1666
0.2671 0.1870touch 1.52E+06
5.47E+02
4.38E-03 0.00306
469.96E-01
E. coliingestion 1.22E+06
3.05E+04
1.18E-01 0.08271
098.82E-01
0.1206touch 1.22E+06
4.39E+02
2.76E-03 0.00193
49.97E-01
VIRUSES
Rhino virus
Oro-fecal
ingestion 1.00E+002.50E-
02 2.47E-02
1.58E-02
9.75E-01 0.0247
0.0250 0.0160touch 1.00E+00
3.60E-04
3.60E-042.30E-
041.00E+00 0.0004
RSVingestion 1.00E+00
2.50E-02
2.49E-061.60E-
061.00E+00 0.0000
touch 1.00E+003.60E-
04 3.59E-08
2.30E-08
1.00E+00 0.0000
MEN
21-30
Rhino virus
Nasal
1.00E-014.34E-
01 3.52E-01
2.25E-01
6.48E-01
0.7169
0.7169 0.4588
31-40 1.00E-014.22E-
01 3.44E-01
2.20E-01
6.56E-01
41-50 1.00E-014.06E-
01 3.34E-01
2.14E-01
6.66E-01
21-30
RSV
1.00E-014.34E-
01 4.33E-05
2.77E-05
1.00E+00
0.000131-40 1.00E-014.22E-
01 4.21E-05
2.70E-05
1.00E+00
41-50 1.00E-014.06E-
01 4.05E-05
2.59E-05
1.00E+00
WOMEN
21-30
Rhino virus
Nasal
1.00E-013.36E-
01 2.86E-01
1.83E-01
7.14E-01
0.6269
0.6270 0.4013
31-40 1.00E-013.42E-
01 2.90E-01
1.85E-01
7.10E-01
41-50 1.00E-013.08E-
01 2.65E-01
1.70E-01
7.35E-01
21-30
RSV
1.00E-013.36E-
01 3.36E-05
2.15E-05
1.00E+00
0.000131-40 1.00E-013.42E-
01 3.41E-05
2.18E-05
1.00E+00
41-50 1.00E-013.08E-
01 3.07E-05
1.97E-05
1.00E+00
Total Working hrs:
Groups Age Biological IndicatorsRoute of entry:
Type of transfer
Conc present in Garbage: (CFU/g; PFU/g, PFU/m3)
Dose value
Risk of infection (r1)
risk of infection(r2)
Risk of Illness
1-r(n)Cumulative risk
Cumulative risk for Bacteria/ Virus
Cumulative Risk of Illness for Bacteria/ Virus
Non-government
10hr
ALL all age
BACTERIA
Salmonella
Oro-fecal
ingestion 1.52E+066.33E+0
42.13E-01
0.1493005
7.87E-010.2167
0.3440 0.2408touch 1.52E+06
5.47E+02
4.38E-03 0.003064
69.96E-01
E. coliingestion 1.22E+06
5.08E+04
1.60E-01 0.112139
78.40E-01
0.1625touch 1.22E+06
4.39E+02
2.76E-03 0.001934 9.97E-01
VIRUSES
Rhino virusOro-fecal
ingestion 1.00E+00 4.17E-02 4.08E-02 2.61E-02 9.59E-01 0.0408
0.0412 0.0263touch 1.00E+00 3.60E-04 3.60E-04 2.30E-04 1.00E+00 0.0004
RSVingestion 1.00E+00 4.17E-02 4.16E-06 2.66E-06 1.00E+00 0.0000touch 1.00E+00 3.60E-04 3.59E-08 2.30E-08 1.00E+00 0.0000
MEN
21-30Rhino virus
Nasal
1.00E-01 7.23E-01 5.15E-01 3.30E-01 4.85E-010.8780
0.8780 0.5619
31-40 1.00E-01 7.03E-01 5.05E-01 3.23E-01 4.95E-0141-50 1.00E-01 6.77E-01 4.92E-01 3.15E-01 5.08E-0121-30
RSV1.00E-01 7.23E-01 7.22E-05 4.62E-05 1.00E+00
0.000231-40 1.00E-01 7.03E-01 7.02E-05 4.49E-05 1.00E+0041-50 1.00E-01 6.77E-01 6.75E-05 4.32E-05 1.00E+00
10hr
WOMEN
21-30
VIRUSES
Rhino virus
Nasal
1.00E-01 5.60E-01 4.29E-01 2.75E-01 5.71E-010.8067
0.8067 0.5163
31-40 1.00E-01 5.70E-01 4.34E-01 2.78E-01 5.66E-0141-50 1.00E-01 5.13E-01 4.01E-01 2.57E-01 5.99E-0121-30
RSV1.00E-01 5.60E-01 5.59E-05 3.58E-05 1.00E+00
0.000231-40 1.00E-01 5.70E-01 5.69E-05 3.64E-05 1.00E+0041-50 1.00E-01 5.13E-01 5.12E-05 3.28E-05 1.00E+00
BOYS
11-20y VIRUSESRhino virus
Nasal
1.00E-01 7.18E-01 5.12E-01 3.28E-01 4.88E-010.7195
0.4605
GIRLS 1.00E-01 5.53E-01 4.25E-01 2.72E-01 5.75E-01BOYS
RSV1.00E-01 7.18E-01 7.16E-05 4.59E-05 1.00E+00
0.0001 0.0001GIRLS 1.00E-01 5.53E-01 5.52E-05 3.53E-05 1.00E+00BOYS
6-10y VIRUSESRhino virus
Nasal
1.00E-01 4.41E-01 3.57E-01 2.28E-01 6.43E-010.5731
0.3668
GIRLS 1.00E-01 4.10E-01 3.36E-01 2.15E-01 6.64E-01BOYS
RSV1.00E-01 4.41E-01 4.40E-05 2.82E-05 1.00E+00
0.0001 0.0001GIRLS 1.00E-01 4.10E-01 4.09E-05 2.62E-05 1.00E+00
BOYS
2-5y VIRUSESRhino virus
Nasal
1.00E-01 3.17E-01 2.71E-01 1.74E-01 7.29E-010.4571
0.2925
GIRLS 1.00E-01 2.94E-01 2.55E-01 1.63E-01 7.45E-01BOYS
RSV1.00E-01 3.17E-01 3.16E-05 2.02E-05 1.00E+00
0.0001 0.0000GIRLS 1.00E-01 2.94E-01 2.94E-05 1.88E-05 1.00E+00BOYS
less than 2 VIRUSESRhino virus
Nasal
1.00E-01 2.13E-01 1.92E-01 1.23E-01 8.08E-010.3380
0.2163
GIRLS 1.00E-01 1.99E-01 1.81E-01 1.16E-01 8.19E-01BOYS
RSV1.00E-01 2.13E-01 2.13E-05 1.36E-05 1.00E+00
0.0000 0.0000GIRLS 1.00E-01 1.99E-01 1.99E-05 1.27E-05 1.00E+00
Bacteria VirusAll
0.187
0.016
0.2408
0.0263
risk of illness from bacteria and virus through Oro-fecal route
Govt. Workers Non-Govt. Workers
Govt. Workers Non-Govt. Workers
Govt. Workers Non-Govt. Workers
Govt. Workers Non-Govt. Workers
All Men Women
0.187
0.2408
0.4588
0.5619
0.40126
0.5163
Cumulative probabilities for risk of illness
gov.
men
risk
of i
nfec
tion
non
gov.
men
risk
of i
nfec
tion
gov.
wom
enris
k of
infe
ction
non
gov.
wom
enris
k of
infe
ction
0.000000
0.100000
0.200000
0.300000
0.400000
0.500000
0.600000
risk of illness
21-30 31-40 41-50
Summary Amongst the bacteria, Salmonella had higher
risk of illness than E. coli Rhinovirus was found to have the highest risk
of illness amongst all the four biological indicators.
The non-government workers at the landfill were at a higher risk.
Women and children were at lower risk than men.
People working for longer hours are affected more.
However, the risk decreases by 99.98% when hand wash is used as an intervention.
Systemic issues for adequate risk management
No adequate data for microbial concentrations in solid wastes
Poor waste handling practices despite of being provided with protective equipment like – Gum boots, Masks, and Gloves
Lack of awareness Lack of training Lack of Human resource
Services to be provided for child rag pickers:
Discourage rag picking by children Raise the minimum age for entry into hazardous work to
18 Define the list of hazardous work Enroll all the rag pickers into schools Encourage NGOs and CBOs to work for children Increase vigilance to do away with children in rag
picking Devote more resources to enforcement of child labor
laws. Provide educational, prevocational, counseling, medical,
recreation and entertainment activities.
THANK YOU
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