This document summarizes a health risk assessment for rag pickers conducted in Pipali, India. It finds that: 1) Rag pickers are exposed to high concentrations of pathogens like Staphylococcus aureus through skin contact with waste, inhalation of aerosols, and hand-to-mouth transfer. 2) Risk analysis shows infection risks from S. aureus exceed internationally accepted safe levels through both skin wounds and oral ingestion. 3) While hand washing provides some reduction, barriers like gloves and masks are likely more effective at preventing initial skin contamination and subsequent infection through wounds or ingestion. 4) Rag pickers should be informed of risks and provided affordable protective equipment,

1. Health Risk Assessment for Rag Pickers
QMRA Solid Waste Group
Kelly Baker, Firew Lemma, Shrawan Singh

2. • Demographics
– Mix of men and
women
– Adults and Children
– Predominantly low
Socio economic
status
• End product results
in recyclables that
can be sold

3. Pipali
-Urban
-Tropical climate
-Low-income

4. 0
2
4
6
8
10
TotalConcentration(CFU/g)
Concentration of Microbial Indicators
in Waste at Dump Sites

5. Exposure Route: Unprotected Skin

6. Exposure Route: Eating using
Unwashed hands at the Site

7. Exposure Route: Inhalation of
Aerosolized Matter

8. 0
2
4
6
8
10
TotalConcentration(CFU/g)
Concentration of Microbial Indicators
in Waste at Dump Sites

9. Percentage Distribution of Microbial Indicators
Isolated from Saliva, Urine, Stool, and/or Nasal
Passages of Rag Pickers
0%
20%
40%
60%
80%
100%
Indicators/PathogensObserved
Rag Pickers
Control

10. Staphylococcus aereus
• Gram +
• Environmental ecology
– Resistant to inactivation via UV, desiccation, etc.
• Not always pathogenic
• Pathogenic forms possess virulence genes encoding toxins
that can adhere to cells and inactivate antibodies, enabling
the bacterium to colonize cell surfaces and resist
immunological clearance.
• Acute Disease pathology
– Skin boils
– Respiratory disease (sinusitis)
– Gastrointestinal disease via food poisoning
• Infection of 100,000 organisms sufficient to produce enough
endotoxin to cause food intoxication
• Antibiotic-resistant forms of pathogenic S. aureus (e.g.
MRSA) is a worldwide problem in clinical medicine.

11. Health Profile of Rag Pickers:
Haematological Indicators
0 20 40 60 80 100 120
Haemoglobin(gdL-1)
Wbc(x 109 L-1)
Haematocrit (%)
Neutrophil (%)
Lymphocytes (%)
Monocytes (%)
Eosinophils (%)
Basophils (%)
Control
Rag Pickers

12. Rag Picker Risk Framework
Microbial
Concentration
(cfu/g)
Volume of
waste per day
(g/day)
Total
concentration in
waste/day
(cfu/day)
Transfer efficiency by air to
mouth (TEHS) * Frequency
breaths/day (ƒHM=1)
Duration of 8-12
hours/day at site * 0.75 kg
waste collected/hour * 5
Decay rate
(e(-kt))
Infection
Infection
Infection
Dose-response
(DR =
dose/person)
CFUw/g * Waste collected/day * total volume* e(-kt) = CFU/day * AWC * PW * ƒOS * TEOS = Ds * DRS
= Ds * ƒHM * TEHM = DM * DRG
Dose ingested
hand-to-mouth
in 5 minutes (DO)
Dose inhaled
Dose transferred
object to skin in 5
minutes (DS)
Transfer efficiency
object to skin (TEOS)
Frequency contact
hand-to-mouth (ƒHM)
Transfer efficiency
hands - mouth (TEHM)
Area of hand and
arm contacting
waste (ACO)
= infection skin
= infection gastrointestinal
Probability of
wound (PW =
0.8)
Total area of
hand/arm with
open wound (AWC)
frequency contact object
and skin (ƒOS)
*set to 1 as constant

13. Concentration Equation
Microbial
Concentration
(cfu/g)
Volume of
waste per day
(g/day)
Total
concentration in
waste/day
(cfu/day)
Duration of 8-12
hours/day at site * 0.75 kg
waste collected/hour * 5
Decay rate
(e(-kt))
CFU/g * Waste collected/day * total volume handled per day * e(-kt)
= CFU/day
Where t = ƒ (t | hours at dump site)
CFU/g * 7.5 kg/day * 5 * e(-0.06*t) = CFU (Staphylococcus aereus)/day

14. Subcutaneous Exposure Dose via Fomite to Skin Wound
Total
concentration in
waste/day
(cfu/day)
CFU/day * AWC * 0.8* 1* TEOS = Ds (Dose through wound on skin)
Where AWC = 0.0203 cm2
(AHAND*0.5)+(AARM*0.25)
Dose transferred
object to skin in 5
minutes (DS)
Transfer efficiency
object to skin (TEOS)
Area of hand and
arm contacting
waste (ACO)
Probability of
wound (PW =
0.8)
Total area of
hand/arm with
open wound (AWC)
frequency contact object
and skin (ƒOS)
*set to 1 as constant
CFU/day * AWC * PW * ƒOS * TEOS = Ds (Dose through wound on skin)
Where AWC = AW
ACO
Microbial
Concentration
(cfu/g)
Volume of
waste per day
(g/day)
Duration of 8-12
hours/day at site * 0.75 kg
waste collected/hour * 5
Decay rate
(e(-kt))

15. Gastrointestinal Exposure Dose via Hand-to-Mouth
Total
concentration in
waste/day
(cfu/day)
Dose ingested
hand-to-mouth
in 5 minutes (DO)
Dose transferred
object to skin in 5
minutes (DS)
Transfer efficiency
object to skin (TEOS)
Area of hand and
arm contacting
waste (ACO)
Probability of
wound (PW =
0.8)
Total area of
hand/arm with
open wound (AWC)
frequency contact object
and skin (ƒOS)
*set to 1 as constant
Microbial
Concentration
(cfu/g)
Volume of
waste per day
(g/day)
Duration of 8-12
hours/day at site * 0.75 kg
waste collected/hour * 5
Decay rate
(e(-kt))
Frequency contact
hand-to-mouth (ƒHM)
Transfer efficiency
hands - mouth (TEHM)
Ds (Dose through wound on skin) = * 1 * TEHM = DO (Dose Oral)
Ds (Dose through wound on skin) = * ƒHM * TEHM = DO (Dose Oral)

16. Rag Picker Risk of Subcutaneous and
gastrointestinal infection
Microbial
Concentration
(cfu/g)
Volume of
waste per day
(g/day)
Total
concentration in
waste/day
(cfu/day)
Duration of 8-12
hours/day at site * 0.75 kg
waste collected/hour * 5
Decay rate
(e(-kt))
Infection
Infection
Dose-response
(DR =
dose/person)
Dose ingested
hand-to-mouth
in 5 minutes (DO)
Dose transferred
object to skin in 5
minutes (DS)
Transfer efficiency
object to skin (TEOS)
Frequency contact
hand-to-mouth (ƒHM)
Transfer efficiency
hands - mouth (TEHM)
Area of hand and
arm contacting
waste (ACO)
Probability of
wound (PW =
0.8)
Total area of
hand/arm with
open wound (AWC)
frequency contact object
and skin (ƒOS)
*set to 1 as constant
Ds (Dose through wound on skin) = * ƒ (DR | µ) = RS
(Risk of subcutaneous infection via skin)
Ds (Dose through wound on skin) = * ƒ (DR | µ) = RO
(Risk of gastrointestinal infection via mouth)

17. Assumptions
Parameters Value References
Hours of working 10 hr/day Ray et al., 2004
Waste Handling rate 0.75 kg/hr Ray et al., 2004
Total recyclables Handling 7.5 kg/day Ray et al., 2004
Total waste Handling 5 fold Group assumption
Microbial Decay constant 0.06 Perez-rodriguez, 2013
Size of wound 0.0203 cm2 Group decision
Area of hand and arm adult 4510 cm2 EPA, 2011 edi.
Proportion of arm exposed 0.25 Group assumption
Proportion of hand exposed 0.5 Group assumption
Probability of having a wound 0.8 Ray et al., 2004
Transfer efficiency - fomite to skin 0.67 cfu/cm2 Lopez, et al., 2013
Transfer efficiency – skin to mouth 0.34 cfu/cm2 Ryen et al., 2014
K (median Staph Dose Response from
normal distribution)
8.21*10-8 cfu/cm2 Rose and Hass, 1999
Efficacy of Hand washing with soap 0.99 Luby, 2006

20. Assumed Safe Risk
1.0E-06
1.0E-05
1.0E-04
1.0E-03
1.0E-02
1.0E-01
1.0E+00RiskofInfection(%)

21. Risk due to Staph Exposure in Wounds
1.0E-06
1.0E-05
1.0E-04
1.0E-03
1.0E-02
1.0E-01
1.0E+00RiskofInfection(%)
Considered Safe Limit
Wound Exposure

22. Risk due to Oral Ingestion
1.0E-06
1.0E-05
1.0E-04
1.0E-03
1.0E-02
1.0E-01
1.0E+00RiskofInfection(%)
Considered Safe Limit
Oral ingestion Exposure

23. Risk Mitigation and Policy
• What is the impact of various occupational
interventions on the risk of Staphylococcus
aereus infection among rag pickers by skin,
oral, and respiratory pathways?
– Hand washing or hand sanitizer
– Masks
– Appropriate clothing barriers - footwear and
gloves
• Which might be most effective?

24. Rag Picker Risk Framework
Microbial
Concentration
(cfu/g)
Volume of
waste per day
(g/day)
Total
concentration in
waste/day
(cfu/day)
Duration of 8-12
hours/day at site * 0.75 kg
waste collected/hour * 5
Decay rate
(e(-kt))
Infection
Infection
Dose-response
(DR =
dose/person)
Dose ingested
hand-to-mouth
in 5 minutes (DM)
Dose transferred
object to skin in 5
minutes (DS)
Transfer efficiency
object to skin (TEOS)
Frequency contact
hand-to-mouth (ƒHM)
Transfer efficiency
hands - mouth (TEHM)
Area of hand and
arm contacting
waste (ACO)
= hand washing interventions
= barrier interventions
Probability of
wound (PW =
0.8)
Total area of
hand/arm with
open wound (AWC)
frequency contact object
and skin (ƒOS)
*set to 1 as constant

26. Risk due to Oral Ingestion After
Washing the Exposed Body Parts
1.0E-06
1.0E-05
1.0E-04
1.0E-03
1.0E-02
1.0E-01
1.0E+00RiskofInfection(%)
Considered Safe Limit
Oral ingestion Exposure
Oral ingestion Exposure after Hand
Washing

27. Conclusions - Intervention Impact
• Hand washing with soap: typically 99% effective
– Not likely to prevent infection of wound;
• Exposure of wound to contaminated fomite is immediate
• Could reduce overall contamination on hands if practiced
frequently
– Not effective at preventing oral infection; cfu of
Staphylococcus aereus deposited on hands is still
>100,000cfu/wound
• Barriers like gloves (Not analyzed)
– Act upstream of both exposure pathways by
preventing hand contamination
– % effective

28. Risk Communication
• Rag pickers need to be informed of their occupational
risk of exposure to high concentrations of hazardous
pathogens.
• Waste sites are so contaminated by some organisms
that follow-up hand washing may not be effective.
• Barriers, like the use of gloves (and masks) are far more
likely to prevent skin contamination that can lead to
bacterial entry into wounds and ingestion by mouth.
• Rag pickers need to be provided access to affordable
and comfortable gloves, shoes, and clothing to protect
themselves.

29. Acknowledgments
• Drexel team - Dr. Patrick Gurian
• IITD team – Dr. Kumar
• Mentors – Drs. Nema and Mittal