Water Monitoring and Contamination Agricultural Water Monitoring... · •Hydrogen peroxide and...

Water Monitoring and ContaminationAgricultural Water

Juan L. Silva, Vladimir Escalante, Taejo Kim, Lorena Luna Guevara, Juan Jose Luna,

Miguel Angel de los Santos

Thank you

• Dr. Alex Castillo, Ms. Cindy Anderson

• PSA

• JIFSAN (Dr Jim Rushing)

• My collaborators and students

2

Outline

• Microbiological water contaminants

• Produce Safety Rule, 21CFR112

• Water microbial indicators and standards

• Agricultural water treatments

– Filtration/suspension

– Conventional

– Oxidation (AOP)

• Conclusions

3

Produce related outbreaks

4

Contamination Routes

5Zhu et al, 2017

Selected outbreaks caused by contaminated water

• S. Muenchen, ice for juice

• S. Javiana y Montevideo, wash water for tomatoes

• S. Saintpaul, jalapenos

• Salmonella, mangos, cold water

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• Shigella, green onions

• Hepatitis, water green onions

• V. cholarae, contaminated water in vegetables

• Cryptosporidium, berries

Harris et al, 2003

2006Spinach contamination with irrigation water?E coli O157.H7 by wild boar– 276 cases, 5 deaths

UC Davis Extension

Agricultural Water

• Agricultural water: water that touches harvestable or edible product or food contact surfaces

• Production Water

– Water used in contact with produce during growth: irrigation, fertigation, foliar sprays, frost protection

• Postharvest Water

– Water used during or after harvest: washing, clean containers

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Potential Sources of Surface Water Contamination

Surface Water Source

Wildlife & Domesticated Animal Feces

ManureApplication/

CompostingOperations

Agricultural Runoff

Septic Tank Leakage

Waste Water Discharge

Urban and Environmental

Runoff

Things We Never Thought

Of

Flooding

10

San Francisco Chronicle, 2017 Purdue U, 2017

Pathogen survival in water

Patógeno

Giardia

Cryptosporidium

Salmonella

Campylobacter

Yersinia

E. coli O157:H7

Frozen

< 1día

> 1 año

> 6 meses

2-8 semanas

> 1 año

> 6 meses

Cold (5oC)

2 meses

> 1 año

> 9 meses

< 2 semanas

> 1 año

> 9 meses

Warm (30oC)

< 3 semanas

< 3 meses

> 6 meses

< 1 semana

< 2 semana

< 3 meses

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12

Higher Risk

Agricultural water P(contamination)

Lower Risk

Public Water Supply

Treated

Surface Water

Open to Environment

Ground Water

Microbiological Testing of Water

• The only way to verify that water after

sanitation treatment is effective

• Typically we evaluate using indicator

microorganisms

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Microbial Water Quality Profile: Survey of Surface Water Sources

§

Source Initial and Annual Testing Requirement

Surface

20 or more times over a period of 2 to 4 years

5 or more samples rolled into profile every year after initial survey

• Profile samples must be representative of use and must be

collected as close in time as practicable to, but before, harvest

Indicator microorganisms in surface and groundwater

• 136 samples of surface water and 143 underground water

• Surface water: total coliforms in 99%, Escherichia coli in

97%, & Clostridium perfringens in 73% of surface water

• Total coliforms in 20%, E. coli <1%, & C. perfringens ND in

groundwater

• The use of land - more significant in the concentrations of

bacterial indicators in water

• Presence of septic systems near the sampling site and

depth of the well may be related to coliforms in

groundwater

Struck et al, 2005 15

Séptic System

Well head

30m from septic system

Possible fecal contamination indicator m.o.

Clostridium perfringens: – spore-forming anaerobe

– feces-specific?

– very (too?) resistant spores (can persist for decades of centuries!)

– may be an indicator for protozoan cysts

Bacteroides spp. and Bifidobacteria spp.:– most plentiful in feces (100X more than FC, FS and E. coli)

– strict anaerobes

– poor survival in the presence of air (oxygen)

– poor detection methods: requires strict anaerobic conditions

– Some Bacteroides species may be human-specific

Rhodococcus coprophilus: – plentiful in feces of some animals

– possible animal fecal contamination indicator

BACTERIA ARE NOT ALWAYS GOOD INDICATORS OF VIRUSES AND PROTOZOANS !

17

Water Microbial Indicators

• WHO international standard:

– 1000 fecal coliform bacteria / 100 ml of water

• Standard recommended by the USA (recreational water EPA)

– Indicator 126 MPN of E. coli / 100 ml water

• Agricultural Water (under FSMA PSR):

– No E coli in hand water, ice, direct contact

– MG <126MPN / 100ml and VUE <410MPN

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Relationship between Total, Fecal

Coliforms, E. coli & Patogenos

Total Coliforms

Fecal Coliforms

Escherichia coli

Salmonella

Parasites

Enterobacter

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Water standards

• Test results must be used to calculate Geometric Means and Statistical Threshold Values to compare to water quality criteria in the FSMA Produce Safety Ruleo The geometric mean (GM) is a log-scale

average, the “typical” value

o The statistical threshold value (STV) is a measure of variability, the estimated “high range” value (approximated 90th percentile)

o In the image to the right, both the GM andthe STV values for the data meet criteria

• Tools are available to assist in calculatingthese values

§

GM

(Typ

ica

l va

lue

)

ST

V

(Hig

h-ra

nge)

Contamination (water) microbial indicators

• Total coliforms:

– drinking, bathing and shellfish water standards

– not feces-specific (environmental sources).

• Fecal coliform ("thermotolerant") (FC):

– detect by growing at elevated temperature of 44-45oCTotal

– ditto coliforms, but less so

• E. coli: the "fecal" coliform

– Detect and distinguish from other total and fecal coliforms by Beta-

glucuronidase activity

– may occur naturally in tropical environments (and possibly elsewhere)

• Fecal Streptocococus (FS):

– Mostly Lancefield group D (and some group Q) streptococci and enterococci

– not feces-specific.

• Enterococci:

– More feces-specific sub-set of FS: Enterococcus faecalis & E. faecium

– EPA guideline for bathing water quality

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Possible sources of pathogens in greenhouses

• Water source

• Tanks / pools that store water

• Pipes (biofilms)

• Waste from plants

• Surfaces

• Workers

• Reused containers

22Wick, Fisher & Harmon, 2008

Relationship between the indicator organism concentration and

the risk of exposure of individuals

Risk

# Indicator m.o.

Sobsey, 201623

Water Treatment Technologies

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Conventional Technologies

• Chemical methods– Coagulation, flocculation, combined with flotation

and filtration, precipitation, ion exchange, electroflotation, electrokinetic coagulation.

• Physical methods– Filtration and membrane filtration processes

(nanofiltration, reverse osmosis, electrodialysis, ...) and adsorption techniques.

• Biological treatments– Biodegradation methods such as fungal

discoloration, microbial degradation, adsorption by microbial biomass (live or dead) and bioremediation systems

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Coagulation

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Floculation

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Factors Influencing Disinfection Efficacy and

Microbial InactivationMicrobe type: Resistance to chemical disinfectants:

• Vegetative bacteria: Salmonella, coliforms, etc.: low

• Enteric viruses: coliphages, HAV, Noroviruses: Moderate

• Bacterial Spores

• Fungal Spores

• Protozoan (oo)cysts, spores, helminth ova, etc.

– Cryptosporidium parvum oocysts

– Giardia lamblia cysts

– Ascaris lumbricoides ova

– Acid-fast bacteria: Mycobacterium spp.

Least

Most

High

Resistance:

Cryptosporidium Removals by Coagulation

(Jar Test Studies)

Coagulant Dose

(mg/L)

Oocyst Removal, % (log10)

Alum 5

1

99.8 (2.7)

87 (0.9)

Iron 6

5

99.5 (2.3)

97 (1.5)

From Sobsey, 2007

Sedimentation y Centrifugation

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Filtration

31lindsay.com

32

Water disinfection

• Chlorine/hipochlorites

• Chlorine dioxide

• Ozone

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Inactivation of Cryptosporidium Oocysts in Water

by Chemical Disinfectants

Disinfectant CT99 (mg-min/L) Reference

Free Chlorine 7,200+ Korich et al., 1990

Monochloramine 7,200+ Korich et al., 1990

Chlorine Dioxide >78 Korich et al., 1990

Mixed oxidants <120 Venczel et al., 1997

Ozone ~3-18 Finch et al., 1994

Korich et al., 1990

Owens et al., 1994

CT99 – Concentration* contact time for 2D reduction

C. parvum oocysts inactivated by low doses of UV radiation: <10 mJ/cm2

Advanced Oxidation Processes (AOP)

35

Science Direct

Water treatment

36Sustainable Sanitation and Water Management Toolbox

Oxidizing substances

• Hydrogen peroxide and other inorganic peroxides• Nitric Acid and Nitrates• Chlorides, chlorate, perchlorate and other analogous

halogenated compounds• Hypochlorite and other hypohalite compounds such

as bleach• Fluorine and other halogens• Ozone• Nitrous oxide (N2O)• Silver oxide• Permanganate salts

37

Radical formation

38www.sbmc.or.jp

Chlorine byproducts breakdown

39

Some applications AOP

40

Avocado Agricultural Water Treatment

41

Water Treatment Pesticide Application

42

ClO2 Effectiveness

43lenntech.com http://isiasistemi.it

Surface wáter- contaminated?

Water remediation at source

• Contaminated wáter can be treated for ag use

• Can use multiple ttreatment steps

– Multiple Filtration (en multi-etapas), irradiación UV,

desinfectanes

– Have to validate to verify their effectiveness

Green onions irrigation using canal water- micro hazards?

Filtration & CL injection for Surface wáter to be

used in drip irrigation

Unidad de Tratamiento del Agua Agricola

Mobile ClO2 wáter treatment unit

Recontamination?

?

Field washing

Hazard?/

Advanced Oxidation Process

54

Ruiz-Aguirre et al, 2017

55

Conclusions

• Water is a contaminant of F & V

• Appropriate indicators for the contaminant

• Treatment can be the only alternative (Agricultural water)

• The treatment has to be appropriate

• PAO can be effective and do not affect the environment

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Muchas gracias

57

Juan L. Silva

jls46@msstate.edu