Arsenic in groundwater

ARSENIC IN GROUNDWATER AND ITS IMPACTS ON HUMAN
HEALTH

Group 15. Nguyen Hanh Mai
Vuong Tran Quang
Nguyen Son Tung


CONTENTS

I. Overview

II. Toxic mechanism

III. Impacts on Human health

IV. Conclusion

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OVERVIEW

What is Arsenic?

 Discovered in 2500 BC
 Documented in 1250
 Metalloid
 Notoriously poisonous to multi-cellular life

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OVERVIEW
Properties







Solid
Arsenic exists in compound forms :
Inorganic (minerals)
Organic
Allotropes



gray
yellow
Pure arsenic is not toxic

black

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OVERVIEW

Arsenic contamination of groundwater




Naturally occur, mining techniques increase arsenic
In groundwater :

 80% : H2AsO4- (pH~7), HAsO42- (pH>7)
 20% : H3AsO3
 Arsenic poisoning of drinking water affects 137 million people in more than
70 countries

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OVERVIEW
Distribution

0.01 mg/L, WHO 2004, Drinking water quality guidelines for Arsenic

6


OVERVIEW
Distribution

0.05 mg/L, QCVN 09:2008/BTNMT

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TOXIC MECHANISM
Exposure Pathways



Primary exposure pathway : Ingestion (water and food)



Minor pathway : Dermal absorption

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TOXIC MECHANISM
Distribution in body






Absorbed from the gastrointestinal tract
and lungs
Widely distributed in most tissues of the
organisms
Great concentrations : liver, kidney,
lungs, skin

Small concentrations : bone, muscles, hair,
nails

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TOXIC MECHANISM
Coagulation of proteins

Highly concentrated As attacks to bond of sulfur group preserving
structure of order 2 or 3

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TOXIC MECHANISM

Interfere activities of enzymes

As

3+

attacks –SH groups of enzymes

H 2O

HS
R'

As O

S
R'

+
HS

As
S

R

R

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TOXIC MECHANISM

Prevention of ATP production

Energy producing enzymes is inhibited by producing complex compounds with As



Normal process :

2322OHC – CHOH – CH-OPO2 + PO4  OCOPO2 - CHOH – CH-OPO2 + OH

 ATP



Process affected by As :

2322OHC – CHOH – CH-OPO2 + AsO4  OCOAsO2 - CHOH – CH-OPO2 + OH

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IMPACTS ON HUMAN HEALTH

Skin lesions

Blackfoot disease

Hepatomely, Cirrhosis

Chronic

altered heme

Exposure

Bone marrow

Nausea, Gastrointestinal

depression

distress, Diarrhoea

Anaemia &
IMPACTS

metabolism

Leucopoenia
Acute Exposure

Sensory loss
Peripheral neuropathy,
Encepalopathy

Diabetes
Proximal tubule

Cardiac arrhythmias

degeneration , Papillary ,
Coritical necrosis

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IMPACTS ON HUMAN HEALTH
Chronic Exposure

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IMPACTS ON HUMAN HEALTH
Acute Exposure

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IMPACTS ON HUMAN HEALTH
Chronic Oral Reference Exposure Level





Study : Tseng et al., 1968; Tseng, 1977




Critical effects : Hyperpigmentation, keratosis, and possible vascular complications





NOAEL : 0.009 mg/L (0.0008 mg/kg.day)






Average exposure : 0.0008 mg/kg.day for NOAEL group

Study population : >40,000 residentially exposed individuals
Exposure method : Drinking water (residential exposures)

LOAEL : 0.17 mg/L (0.014 mg/kg.day)

Exposure continuity : Not applicable
Exposure duration : Lifetime

Human equivalent concentration : 0.0008 mg/kg.day for NOAEL group
Oral reference exposure level : 0.3 µg/kg bw.day

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IMPACTS ON HUMAN HEALTH
Health Risk Assessment

Assumption : Thanh Xuan District 12/2012
C = 40x10 µg/L = 0.4 mg/L
ED = 60 years
CR = 2.0 L/day
BW = 60 kg
EF = 7 day/week
AT = 60 years



 High risk

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CONCLUSION






Widely distributed, mostly in South and Southeast Asia (include Vietnam)
Greatly affect : 137 million people (only in 2007)
Cause 19 different acute and chronic diseases
High risk to have cancer (HQ = 125)

 Spread this issue and find more solutions to reduce Arsenic in
groundwater

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REFERENCES
1.

Lenny H.E.Winkel, Nguyen Thi Ha. Arsenic Pollution of Groundwater in Vietnam Exacerbated by Deep Aquifer Exploitation for more than a Century. Proceedings of National
Academy of Sciences (January 25, 2011). Volume 108, No.4 : 1246-1251

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Batch 2A (December 2000). Determination of Noncancer Chronic Reference Exposure Levels. A-8 – A-28
Obinaju (May 20, 2009). Mechanisms of Arsenic Toxicity and Carcinogenesis
R.N.Ratnaike. Acute and Chronic Arsenic Toxicity. Postgraduate Medical Journal (2003) 79:391-396
Dipankar Chakraborti. Status of Groundwater Arsenic Contamination in the State of West Bengal, India: A 20-year Study Report. Molecular Nutrition & Food Research (2009).
53:542-551

7.

Amitava Mukherjee. Arsenic Contamination in Groundwater : A Global Perspective with Emphasis on the Asian Scenario. Journal of Health, Population and Nutrition (June
2006). 24(2):142-163

8.

Md. Khalequzzaman. Assessment of Arsenic Contamination of Groundwater and Health Problems in Bangladesh. International Journal of Environmental Research and Public
Health (2005). 2(2):204-213

9.
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13.

Wikipedia : Arsenic. Available at (Accessed December 9, 2012)

Wikipedia : Arsenic contamination of groundwater. Available at (Accessed December 9, 2012)
WHO (2004). Drinking Water Quality Guidelines for Arsenic
QCVN 09:2008/BTNMT
Tran Thi Thanh Huong, Le Quoc Tuan. Co che gay doc Arsen va kha nang giai doc arsen cua vi sinh vat. Workshop on Environment and Sustainable Development, Con Dao
National Park (June 2010)

14.

Le Huy Ba. Doc hoc moi truong (tap 2), Chuong 7

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THANKS
FOR LISTENING!

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