Biological indicator – Water quality

Eleni Diapouli MSc in Water Resources Management

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Water Framework Directive

The sustainable management of water resources is a tool

to serve the main objective of Directive 2000/60/EC, which

is the protection and the enhancement of the aquatic

environment.

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Sources of Pollution 1/2

Pollution from agriculture (fertilizers, pesticides,

insecticides). They have non-point character and therefore

their management is difficult).

Industrial wastewater (industrial wastewater

treatment plants are usually present only in large

industries).

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Sources of Pollution 2/2

Disposal of liquid and solid waste - household

waste (food scraps, etc).

Products of mining activity (heavy metals, arsenic

e.t.c, harmful chemical compounds).

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Biotic - Biological Indicators

The concept of a Biological Indicator is based on the

determination of the water quality (and correspondingly

the level of eutrophication or the degree of pollution) based

on the organisms living in it.

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They are used:

for detecting changes in the natural environment,

for monitoring the presence of contamination and/or

pollution,

for monitoring progress of environmental rehabilitation and

control substances (e.g drinking water) for the presence of

contaminants.

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Biological indicators should meet the following specifications:

Be easily identified,

Be sensitive to the pressures on the aquatic ecosystem,

React to the pressure in a predictable way,

Predict the disorders that can be prevented with

appropriate management actions,

Have known reactions to natural changes and human

pressures.

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Types of aquatic ecosystems

The main types of aquatic ecosystems are:

1. Ecosystems in coastal waters

- Seas, Lagoons

2. Ecosystems inland

- Lakes

- Rivers, Streams, creeks

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Ecosystem inland

To assess the quality of rivers & lakes different groups of

aquatic organisms are used :

phytoplankton,

Macrophytes (macroalgae, marine phanerogams)

Fish fauna (Rutilus rutilus, Cyprinus carpio, etc.)

Phytobenthos (mainly diatoms),

Macroinvertebrates etc..

The benthic macroinvertebrates are widely used as biotic

indicators for estimating humans interventions on the quality

of surface waters.

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Advantages - Disadvantages

A comparative table is presented below about the advantages

and disadvantages of the use of macroinvertebrates as

biomarkers in flowing waters.

Table: Advantages and disadvantages of using macroinvertebrates as bioindicators in ecosystems watercourses

Advantages Disadvantages

Low mobility Lack of response to all types of contaminants

Large number of species Seasonal changes in their distribution

High degree of sensitivity to various pollutants

Large numbers of samples

Simple and low cost sampling

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Comparative Evaluation of biological quality elements

Characteristics of the groups Macroinvertebrates Diatoms Macrophytes Algae

Fish

Information for life distribution and environmental requirements

+++ +++ ?/++ ?/+ +++

Existence of historical data ++ ?/+ ?/+ ?/+ +++

Long life cycle +++ + +++ ++ +++

Low degree of mobility +++ +++ +++ +++ +

Ability to recognize and easily classification (level of species)

+++ +++ ?/++ ?/++ ++

Ability to recognize and easily classification (family level)

+++ +++ +++ +++ +++

Convenience of sampling method +++ +++ ++ ++ +

Degree of impact on habitat sampling + + + + +

Sensitivity to various types of pollution ++/? +++ +/? + +/?

Indication of long-term changes + ? +/? +/? +

Indication of short-term changes ++ ++ +/? + +/?

+++: strong advantage for this feature as biological quality element. ++: advantage of this feature as a biological quality element. +: this feature is not a significant advantage as biological quality element. ++/?: this feature as a biological quality element is an important advantage in some cases only. +/?: this feature as a biological quality element is an advantage only in certain cases.

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Ecosystem in coastal waters

To assess the quality of coastal waters the following group of

species are used:

phytoplankton

Macrophytes and Angiosperms

Macroinvertebrates

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Conclusions – Classes of quality

Ecological status classes of water quality in accordance with

the Framework Directive:

High quality (undisturbed conditions, micro degraded

conditions)

Good quality (low scale anthropogenic interference, small

deviation from the undisturbed conditions)

Poor quality (large deviation from the undisturbed

conditions, degradation)

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Eutrophication of marine waters

It occurs in ponds or in enclosed shallow bays under certain

conditions,

It is created by increasing the concentration of nutrients

such as nitrates and phosphates,

The movement of water is minimal, bacteria and algae grow

consistently, which leads to increased consumption of

dissolved oxygen and reduction of oxygen production.

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The "green carpet" of eutrophication at Thermaikos gulf, Thessaloniki

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Confront the problem of

eutrophication

Biological treatment of waste,

Control in rural and agricultural runoff.

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Conclusions

1. Assessing the quality of water bodies using biotic indices is

based on a general principle according to which the most

sensitive to pollution species disappear in the early stages of

environmental degradation and the most resistant species

survive. This process leads to the reduction of biodiversity as

pollution increases.

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Conclusions

2. To assess the ecological quality of inland waters benthic

macroinvertebrates are widely used. Other evidence should

also be omitted to assess the state of the rivers, which are the

aquatic flora and fish fauna.

3. Determining the typology of water bodies is a very

important factor for the application of biotic indices and

comparison of results between different indicators.

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Conclusions

4. Basic parameters for the application of a biotic indicator is

the method of sampling and the diversity of habitat.

Thanks for your attention