Ecological and Hygienic Consequences of Reservoir Pollution

v Hygienicnegative consequences:

Ø restriction or full liquidation of water use for population,

Ø health disorders of population (water epidemics, acute and chronic poisonings, the remote effects),

Ø deterioration of sanitary life conditions of population, restriction of settlement development,

Ø accumulation of dangerous levels of toxicants and microbes in fish products,

Ø pollution of contact environments — air, ground, underground waters.

v Ecological negative consequences:

Ø reversible and irreversible changes of hydroecosystems,

Ø decrease of efficiency and biomass of hydroecosystems,

Ø loss of rare and valuable species of hydrobionts,

Ø succession of hydroecosystems.

Basic Directions of Protection of Water Reservoirs from Pollution

These include:

v Administrative-legislative measures (laws, Sanitary Standards, etc.).

v Hygienic measures:

Ø Preventive sanitary inspection

§ project appraisal of industrial and other objects, sewage disposal plants as to observance of MPD (maximum permissible discharges) into reservoirs;

§ Normalization of harmful substances in water.

Ø Current sanitary inspection — the control over content of harmful substances and microbes in reservoir water, control of efficiency of purification and disinfecting water, control of water supply system and observance of norms of water consumption.

v Architectural-planning measures — zones of sanitary protection of water sources.

v Medical monitoring includes studying state of population health depending on quality of reservoir water.

v Ecological monitoring consists in researching the effect of pollution on hydroecosystems and separate hydrobionts. Bioindication, biotesting are carried out.

v Technological measures include application of closed technology, decrease of industrial water consumption, change of technology for decreasing toxicants in effluent, sewage disposal plants for cleaning and disinfecting sewage, etc.

Recommendations for Practical Classes on the Theme

Key Questions:

1.Hygienic characteristics of water supply sources, zone of their sanitary protection.

2.Parameters of quality and pollution of water.

3.Methods of improvement of water quality. Methods of water purification and control over their efficiency.

4.Methods of water disinfection, control over their efficiency.

5.Scheme of water chlorination, its types, disadvantages.

6.Special methods of improvement of water quality.

7.Basic sources of reservoir pollution and ways of their self-purification.

8.Standardization of harmful substances in reservoir water.

9.Basic directions of protection of reservoirs from pollution.

Self Test

1. The amount of residual chlorine in water in norm makes up:

A. 0.1 mg/l

B. 0.2 mg/l

*C. 0.3 mg/l

D. 0.4 mg/l

E. 0.5 mg/l

 

2. Identify the chemical element which salts are applied for water coagulation?

*A. Aluminium

B. Fluorine

C. Silver

D. Iron

E. Copper

Final Testing of Students’ Knowledge

1. At substantiation of size of the 2nd sanitary protection zone of water supply sources the duration of water purification from microbes is taken into account. What period of time is necessary to purify underground water from microbes?

A. 400 days

B. 200 days

C. 50 days

D. 5 days

E. 3 days

 

2. The military unit after a long march has stopped for 3 seasons to have a rest near the inhabited locality. According to the data of sanitary-epidemic investigation some water sources are revealed. It is necessary to choose a source, which to a great extent meets the hygienic requirements to drinking water in field conditions.

A. well water

B. artesian well water

C. river water

D. rain water

E. melted snow

Problem Solving

1. What parameters should testify to reliability of carried out disinfection of water in case of applying a hyperchlorination method?

2. At a distance of 20 m from apartment house there is a mineshaft, which is 10 m from a toilet and 15 m from the neighbouring house. What distance should be according to sanitary norms between the well and a source of possible pollution of water?

3. A typhoid epidemic of water origin after the water pipe failure has been registered in inhabited locality N. What are the main signs characteristic of the water epidemic?

Standard Answers

1. Residual chlorine — 0.5 mg/l, coli titer — 100, coli index — 10

2. 30 m

3. The contingent of ill population lives in the same district and a sharp increase of disease incidence, decrease of disease incidence after liquidation of water pipe failure, epidemic tail are characteristic.

Methodical Recommendations for Students’ Independent Work

During the work the students should carry out laboratory researches to determine residual chlorine in water and estimate needs of researched water in chlorine.