water quality monitoring and assessment - kathmandu … monitoring... · water quality monitoring...

Water Quality Monitoringand

Assessment

Interrelationships betweenthe steps used in monitoring

Chemical Monitoring TechniquesBiomonitoring Techniques

Dr. Subodh Sharma 2

Interrelationships betweenthe steps used in monitoring

What type of monitoring is required?Biological:in-situ/ex situ tests?mortality/sub-lethal tests?whole organisms/sub-organism level?Bio-accumulation studies?biotic indices?Bio-monitors/bio-probes?Chemical:continuous? automatic?manual?What determinands/tests/assays, etc. are required?What level of accuracy is required?What sampling methodology / deployment regime should be used:frequency?time(s) of day?sampling sites?

What information is required to fulfil the aims of the sampling programme?

What decisions are to be made on the basis of these results?

What resources are available?

Strictly define monitoring programme

What is the best way to interpret the results?What is the best way to present the results?

Result output and presentation REVIEW

Dr. Subodh Sharma 3

Chemical Monitoring Techniques

Design of monitoring1. Purpose of Monitoring2. Sampling sites3. Sampling frequency (daily/yearly/seasonal)4. Sampling methodology5. Choice of appropriate analytical

methodology

1.Purpose/Types of monitoringa. Cause and effect monitoringb. Baseline monitoringc. Compliance monitoringd. Inventory monitoring

Station A

Station B

Treatment

2. Sampling sites

Fig. An example of site selectionin cause and effect monitoring

Dr. Subodh Sharma 4


4. Sampling methodologya). Laboratory sample processing

Sample-A1 Litre Sample-B

1 Litre

2 6431 5 7 850ml 120ml 100ml 100ml 100ml 100ml

Filter

Absor-bances

pHCond.Turb.

Freeze Filter/Freeze

Filter/Chill

Filter/Chill

In Lab.

Immediately

Few days/week

Within 3 months

Within 1 yearTN, TP NH4, NO3, Cl, SO4

SO4 Ca, Mg, Na, K

350ml 200ml350ml 100ml 100ml

BOD5 BOD5 Alk. Freeze

Filter/ Freeze

TN, TP NH4, NO3, Cl, SO4

From Smith & McBride 1990

Dr. Subodh Sharma 5

Random sampling.Time weighting Random samplingTime weighting Systematic sampling.


3. Automatic : Automatic samplers are used for the collection of routine samples. Eg, 100 ml. sub-samples collected every 5 h into a single container, with a new sampling vessel selected every 25 h.

2. Continuos : Best used for measuring pH and DO, where manual samplecollection is extremely expensive. Equipment are available for ammonium,temperature, turbidity, and chlorophyll-a is currently being developed.

4. Sampling methodologyb). Sampling Process

1. Manual

Dr. Subodh Sharma 6

Case study from Galaudu Pokhare Khola subwatershed

Dr. Subodh Sharma 7

Objectives of the study

Objective 1:To survey, identify and map potential water sources and sites for water harvesting.

Objective 2: To assess sedimentation problem in the two river systems (Galaundu and Pokhare Khola) and establish relationships between land use, biological indicators and water quality.

Objective 3:To develop management schemes for water harvesting and conservation and for optimising water use.

Dr. Subodh Sharma 8

Study Area

27°40´ to 28°14´ N and 84°0´ to 85°1´ETotal area: 27.09 sq. km.Major rivers: Galaundu and Pokhare KholaPopulation: 5305

Dr. Subodh Sharma 9

Methodology

Temperature, pH, conductivity, and dissolvedoxygen were analyzed on site.

Hardness, inorganic ions, heavy metals(Chromium, Copper, Zinc, Lead and Nickel) wereanalyzed in laboratory.

For the Presence/Absence (P/A) test of bacteria in water, two methods were used, such as HiMedia’s user friendly PA Coliform Test Kit (MS1186) and Hydrogen Sulphide Test using test strip in vials.

Dr. Subodh Sharma 10

Results & Discussion

Stagnant water springs

(Kuwa)18%

Taps45%

Ponds3%

Tanks3%

Streams6%

Running water springs (Dhara)

25%


pH

Minimum 5.63(in taps)

Maximum 11.0 (in stream)


Temperature

Minimum 19.0 deg. Celsius

(in stream)

Maximum 24.8 deg. Celsius

(in pond)


Conductivity

Minimum 3.85 μS/cm.(in taps)

Maximum 975 μS/cm.(in taps)


DO

Minimum 0.10 mg/L.(in dhara)

Maximum 6.20 mg/L.(in taps)


Magnesium

Minimum 0.88 mg/L.(in kuwa)

Maximum 20 mg/L.(in taps)


Calcium

Minimum 3.2 mg/L. (in stream)

Maximum 102 mg/L. (in taps)


N-NO2

Minimum 0.00 mg/L.(in stream)

Maximum 0. 054 mg/L.(in stream)


N-NO3(WHO recommended maximum permissible level is 25 mg/L)

Minimum 0.05 mg/L(in Dhara)Maximum 2.4 mg/L(in Dhara)


ChromiumWHO recommended maximum permissible level is 50 μ g/L)

Minimum 1 μg/L.(in taps)

Maximum 15.8 μg/L.(in Dhara)


Copper

Minimum 2.4 μg/L.(in stream)

Maximum 20 μg/L.(in taps)


ZincWHO recommended maximum permissible level is 3000 μ g/L)

Minimum 28 μg/L.(in Dhara)

Maximum 124 μg/L.(in Spring)


LeadWHO recommended maximum permissible level is 10 μ g/L)

Minimum 1.28 μg/L.(in kuwa)

Maximum 30 μg/L.(in taps)


NickelWHO recommended maximum permissible level is 20 μ g/L)

Minimum 1.54 μg/L.(in taps)

Maximum 54 μg/L.(in stream)


Conclusions and Recommendations

pH values were usually higher in the area studied indicating high calcium contents in water .

At this stage, there appears to be no problem of nitrate indrinking water supply, however source protection toprevent likely contamination from agricultural runoff mustbe given priority.

A proper selection of GI pipes is recommended when used inpublic drinking water systems.

The use of lead pipes in pipelines in the presence of corrosivewaters has resulted in higher lead concentrations at thetap in the area studied.


Bio-monitoring techniques

PRINCIPLES OF BIO-MONITORING:• The first category comprises the Bio-assays (Experimental)

• Eco-toxicological tests, bio-accumulation tests, bio-degradation tests, eutrophication tests.

• The second category comprises the Bio-assessments (Observational)• taxa density, taxa richness, proportion between the communities.

ADVANTAGES:• Biological communities act as continuous monitors.• Biological communities respond to a wide range of different water

quality.LIMITATIONS:

• Specific cause of the change is not identifiable.• A comprehensive assessment demands considerable effort in

sampling.


Use of different taxonomic groupsin bio-monitoring

Bacteria algae Macro-invertebrates

Macro-phytes

fish Birds/mammals

Aquatic zone(water body)

++ - / + ++ - / + ++ +

Riparian zone(banks)

_ - + ++ + ++

Terrestrial zone(floodplains)

_ - + ++ _ ++

- = not suitable + = suitable ++= well suitable


Advantages of using Benthicmacro-invertebrates

Good indicators of localized conditions.Integrate the effects of short-term environmental variations.Easily identifiable to family level.Sampling is relatively easy.Serve as food for fish.Are abundant in most streams.


Advantages of using Fish

Fish are good indicators of long-term effects.Fish community structure is reflective of integrated environmental health.Fishes are at the top of the aquatic food chain and are consumed by humans.Relatively easy to collect and identify.


Advantages of using Algae

Algae are good indicators of short-term impacts.Algae are primary producers.Sampling is easy, inexpensive, requires few people.Relatively standard methods exist for characterizing algal communities.Algal communities are sensitive to some pollutants.


Principal approaches to assess water quality

Saprobic approach• is based on the pollution tolerance of the

indicator species present.Diversity approach uses three components• richness• evenness• abundance

Biotic approach• incorporates quantitative measure of species

diversity with qualitative information on the sensitivity of indicator species.


The Saprobic Index

S = ∑ (s.h)/ ∑hwhere S = Saprobic Index, s = saprobic value for each indicator species,

h = frequency of occurrence of each species.the value of S normally ranges from 1 to 4 for ambient waters.

Major criticisms of saprobic systems:The taxonomy is not far enough advanced.The pollution tolerances of species are very subjective.No information on the community as a whole is provided.


The Diversity Index

H’ = ∑ Νι/Ν log2 Νι/Ν where H’ = index value, N = total number of individuals of all species collected, and Ni= number of individuals belonging to the ith species.

They are strictly quantitative.Relatively independent of sample size.Assumptions made are highly subjective.


Biotic IndicesTrent biotic index

England(1964)

Chandler’s ScoreScotland(1970)

BMWP ScoreUK

(1978)

Modified BMWP Score

UK(1979)

Extended Biotic Index

UK(1978)

Chutter’s Biotic Index

South Africa(1972)

Hilsenhoff’s Biotic IndexUK

(1977)

Hilsenhoff’s ImprovedBiotic Index

USA(1987)

Indice BiotiqueFrance(1968)

Indice Biologiquede Qualite GeneraleFrance(1982)

Indice BiologiqueGlobalFrance(1985)

Belgian Biotic Index

Belgium(1983)NEPBIOS

Nepal(1996)


Comparison betweenTrent and Extended Biotic Index

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Tota

l Site

s

CALCULATED WATER QUALITY ACCORDING TO WOODIWISS, 1978

I I-II II II-III III III-IV IV

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Tota

l Site

s

CALCULATED WATER QUALITY ACCORDING TO WOODIWISS, 1964



Comparison betweentwo French Indices

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Tota

l Site

s

CALCULATED WATER QUALITY ACCORDING TO TUFFERY &

VERNEAUX, 1968


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Tota

l Site

s

CALCULATED WATER QUALITY ACCORDING TO TUFFERY &

DAVAINE, 1970



Comparison betweenFrench and Belgian Biotic

Indices

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Tota

l Site

s

CALCULATED WATER QUALITY ACCORDING TO AFNOR, 1985


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Tota

l Site

s

CALCULATED WATER QUALITY ACCORDING TO DE PAUW &

VANHOOREN, 1983



Comparison between British & American Indices

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Tota

l Site

s

CALCULATED WATER QUALITY ACCORDING TO EXTENCE et al.,

1887


0102030405060708090

Tota

l Site

s

CALCULATED WATER QUALITY ACCORDING TO HILSENHOFF, 1988



Conclusions & Recommendation

Biological assessment methods are an integral part of river water quality monitoring.It is recommended that sampling methods be standardized.Where river conditions permit, benthic macroinvertebrates should be used.Every country should establish its index system.In large rivers colonization samples should be used.Other indicator organisms should also be used.

End of Lecture-3

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