pesticide and antibiotic pollution in the mekong delta · pesticide and antibiotic pollution in the...
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Slide 1 Slide 1
Pesticide and antibiotic pollution in the
Mekong Delta
6th WISDOM seminar, 10 – 14 June, 2013 Bonn
Chau, N.D.G., Renaud, F. G., Sebesvari, Z.,
Rosendal, I., Amelung, W
Folie 2 Slide 2
Mekong Deta • 55% of national rice production in 2011
[GSO, 2011]
• 40% of fruits production [Vietnam’s Fruit and
Vegetables association, 2011]
• 60% of fishery production [GSO, 2011]
Increasingly use of pesticides and
antibiotics
Introduction
Risks of exposure to pesticides and antibiotics in water
[Photos : internet]
Folie 3 Slide 3
Main objectives
1. To identify the main pollution sources for pesticides and antibiotics and assess their influence on water quality in the Mekong delta. 2. To link pesticide and antibiotic pollution with human exposure via different drinking water sources 3. To generate GIS based risk maps of drinking water quality by linking hazard (pollution) and exposure (water use for drinking).
Folie 4
Approach
Slide 4
First stage: (August 2011 – March 2012)
Field survey, household interview, expert interview, secondary data
collection
to select study sites, design sample size, sampling frequency and
study compounds
Second stage: (Dec 2011 – May 2013)
Analytical method development
Sampling, sample extraction and analysis
Data treatment and validation
Third stage
Development of GIS risk assessment maps
Folie 5 Slide 5
Study sites
Sampling locations
• Can Tho city and An Giang province
Folie 6 Slide 6
Province Location Land use Soil type Irrigation
Can Tho O Mon
(OM)
Triple paddy rice
crop, fruit tree
Alluvial soil None closed
dyke system
Co Do
(CD)
Double paddy
rice crop, veggies
Slight acid
sulfate soil
None closed
dyke system
Thoi Lai
(TL)
Triple paddy rice
crop
Slight acid
sulfate soil
None closed
dyke system
An Giang Thoai Son
(TS)
Triple paddy rice
crop
Slight acid
sulfate soil
Closed dyke
system
Selected sites for assessment of water
pollution by pesticide use
Study sites
Folie 7 Slide 7
Province Location Land use Soil type Irrigation
Can Tho Co Do
(CD)
Hatchery fish Slight acid
sulfate soil
None closed dyke
system
An Giang Chau Phu
(CP)
Mature catfish
(Pangasius)
Alluvial soil Closed dyke
system
Selected sites for assessment of water
pollution by antibiotic use
Study sites
Folie 8
Results
Slide 8
Folie 9 Slide 9
23
38
54
73
23
6
79
26
68
6 0
80
5
40
75
0
20
40
60
80
100
14 7
83 90
17
30
0
27
67
43
0
20
40
60
80
100
pipe ground rain canal bottled pipe ground rain canal bottled
Thoai Son (n = 29)
Co Do (n = 20) Thoi Lai (n = 34) O Mon (n = 26)
Chau Phu (n = 30)
Percentage of different water sources used by interviewed
households
Folie 10 Slide 10
Types WHO toxic
classification Use (%)
Fenoxaprop-P-ethyl
Herbicide
III 18
Butachlor III 16
Pretilachlor U 63
Azoxystrobin
Fungicide
III 34
Trifloxystrobin III 14
Hexaconazole U 27
Isoprothiolane II 31
Difenoconazole II 83
Propiconazole II 64
Thiamethoxam III 36
Tebuconazole III 10
Quinalphos
Insecticide
III 17
Cypermethrin II 14
Fenobucarb II 19
Fipronil II 38
Selected pesticides
(132 HH)
Folie 11
Selected antibiotics
Slide 11
Use (%) Chemical group
Amoxicillin 18 Penicillins
Ampiciline 12 Penicillins
Cephalexin Monohydrate 6 Penicillins
Chloramphenicol 6 Phenicol
Florfenicol 29 Phenicol
Kanamycin sulfate 6 Aminoglycosides
Spectinomycine 12 Aminoglycosides
Sulfadimethoxin 6 Sulfonamides
Doxycycline 29 Tetracyclines
Oxytetracycline 12 Tetracyclines
Sulfamethoxazole 41 Sulfonamides
Trimethoprim 41 Bacteriostatic antibiotic
Enroflorxacine 47 Fluoroquinolones
(17 HH)
Folie 12
Pesticide pollution
Slide 12
Folie 13
Summary of the residues of pesticides in water for all
samples (n = 270, March 2012 – January 2013)
Slide 13
Compounds Quantification
frequency (%)
Max. conc.
(µg/L)
Median conc.
(µg/L
Butachlor 44.1 0.81 0.25
Pretilachlor 58.9 0.85 0.21
Fenoxapro P ethyl 0 0 0
Propiconazole 27.8 4.76 0.51
Tebuconazole 26.7 1.34 0.34
Hexaconazole 51.5 1.79 0.44
Trifloxystrobin 11.5 0.56 0.15
Isoprothiolane 77.4 8.49 0.47
Difenoconazole 5.2 3.18 1.30
Azoxystrobin 45.9 2.41 0.49
Fenobucarb 70.7 2.18 0.14
Quinalphos 57.4 1.33 0.17
Thiamethoxam 3.0 0.95 0.63
Fipronil 62.2 0.41 0.17
Cypermethrin 0.4 0.77 0.77
EC guideline of the threshold of individual
pesticide in drinking water: 0.1 µg/L
Folie 14 Slide 14
Randomly collected from 84
brands in Can Tho 500 mL bottle 19 L bottle
No. of analyzed samples/ brands 26/ 10 22/ 8
No. of samples contaminated by pesticides 17/26 13/22
Max total pesticide concentration (g/L) 1.38 0.53
Average total pesticides (g/L) 0.42 0.26
No. of samples with individual pesticide residues
Fenobucarb 2 6
Quinalphos 1 1
Butachlor 4
Isoprothiolane 8 6
Pretilachlor 13 3
Fipronil 4
Hexaconazole 3 6
Azoxystrobin 1
No. of samples exceeding EC guideline 0.5 g/L 5 2
Pesticide residues in bottled water
Folie 15
Antibiotic pollution
Slide 15
Folie 16 Slide 16
No.
analyzed
samples
Quantification
frequency (%)
Median
conc.
(µg/L)
Range conc.
(µg/L)
Enroflorxacine 169 38% 0.012 0.001 – 0.081
Sulfamethoxazole 169 78% 0.020 0.001 – 0.239
Trimethoprim 137 84% 0.016 0.001 – 0.330
Summary of the residues of antibiotics in water
(March 2012 to January 2013)
Folie 17
Co Do (n
=24)
Chau Phu 1 (n=31)
Chau Phu 2 (n=29)
Co Do (n
=24)
Chau Phu 1 (n=31)
Chau Phu 2 (n=29)
Co Do (n
=24)
Chau Phu 1 (n=31)
Chau Phu 2 (n=29)
0.00
0.02
0.04
0.06
0.08
0.10
0.12
0.14
Slide 17
µg/L
Enroflorxacine Sulfamethoxazole Trimethoprim
Antibiotic occurrence in Co Do and Chau Phu
0.031
0.012
0.021
0.012 0.014 0.013
0.022
0.017
0.018
p < 0.05
Folie 18
Conclusions
Domestic water: surface water and groundwater are the main sources
Drinking water: surface water is still used (up to 38% of households in
Thoai Son)
Most intensive pesticide use: Thoai Son
Isoprothiolane, fenobucarb and pretilachlor were the 3 most
frequently detected pesticides, median conc. 0.47, 0.14 and 0.17 µg/L,
respectively
Antibiotics: low concentrations, ranging from 0.001 to 0.330 µg/L
93% surface water samples exceed EC guideline for total pesticides
in drinking water (0.5 µg/L)
So far, there are no guidelines for the thresholds of sulfamethoxazole,
trimethoprime and enroflorxacine concentrations in drinking water.
Slide 18
Folie 19
What’s next?
Develop GIS risk maps for drinking water quality
Publiciations on (1) pesticide pollution, and (2)
antibiotic pollution in the Mekong delta
Finish the study on dissipation of some antibiotics
under tropical climate
Slide 19
