arsenic contamination and mitigation in cambodia dr. mickey sampson resource development...

Arsenic Contamination and Mitigation

in Cambodia

Dr. Mickey Sampson

Resource Development International- Cambodia

Wells tested in Kandal

Estimated Population ImpactedUsing 2004 Census data for usage rates

Approximately 102,600 are exposed to arsenic in their drinking water

Sources of Error• People did not report accuratly their source in the census• Education has impacted sources• Better sources now available

Arsenicosis

Mitigation

Approaches

Education is Vital

InfotainmentKaraoke

Methods of Mitigation

• Alternate Water Supply/Sources– Surface Water– Rainwater– Hand Dug Wells (Rope Pumps)

• Removal Technologies– Iron Oxide Co-precipitation– Alumina Hydroxides– Highly technical Media/membranes

Surface Water

Concerns:• Very prone to pathogen contamination• Only available in some areas/season

Water must be treated for Pathogens before use• Boiling (problem storage)

• Ceramic Filter (Availability and proper use)

• Chemical Treatment (taste, cost, amebas)

Rainwater Harvesting

• Weather Dependent

• High cost of storage containers

• Storage Capacity

• Safe Storage

Best Option is when coupled with a well used for sanitation

Rainwater Harvesting

40,000 liters

Hand Dug Wells

• Initial Studies show water is significantly better chemically

• Is available in most high risk areas

• Water is more prone to Pathogenic contamination

• Protecting the source may help

0 20 40 60 80 100

46-70

21 - 45

0 - 20

Wel

l Dep

th (

m)

Number of Wells

As <= 10 ppb

10 < As <= 50 ppb

As > 50 ppb

Rope Pump

Removal Technologies

Nails

Sand Layer

Gravel Layers

Modified BioSand Filter or Kachan

0

50

100

150

200

250

300

350

400

450

Jul Aug Sep Oct

Month

Ars

en

ic C

on

cen

trati

on

(p

pb

)

Filter#1-in

Filter #1-out

Filter #2-in

Filter #2-out

Filter #3-in

Filter #3-outCambodian National Standard

77.2%

84.7%

85.5%

25.7%

45.4%

72%

13.2%

43%

46.7%

70.4%

25.2% 78%

Three different wells were part of the study. We found removal rates varied significantly as did the chemical content in each.

Average overall removal was 39.5%, 47.8% and 75.2%

Arsenic Removal vs. Phosphorus

y = 0.3507x - 0.4634

R2 = 0.7587

0.0%

10.0%

20.0%

30.0%

40.0%

50.0%

60.0%

70.0%

80.0%

90.0%

0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00

Fe / P Ratio

Ars

enic

Rem

oval

%

\

Removal Technologies

• Only used as a last resort

• Technologies need further testing and evaluation

• Systems need to be low maintenance and inexpensive

Piped Water

Thank you

www.rdic.org