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Criteria of drinking water quality
Criteria, units of measurement
Odour, points
Turbidity, mg/l
Spectral colour, degrees
Aftertaste, points
Hydrogen index, pH value, within the range, units.
Iron, mg/l
Total hardness, mg-equiv/l
Sulphates, mg/l
Solid residue (total mineralization), mg/l
Polyphosphate residue, mg/l
Chlorides, mg/l
Copper, mg/l
Manganese, mg/l
Zinc, mg/l
Chlorophenols, mg/l
Sanitary rules and norms
(State sanitary rules and
norms)
2*
0.5 (1.5)**
20 (35)***
2*
6.5—8.5
0.3
7.0 (10.0)
250 (500)
1000 (1500)
—
250 (350)
1.0
0.1
—
0.0003
Criteria of drinking water
Indices, units of measurement
Amount of bacteria in 1 ml of water (total microbial
number, TMN), CFU /ml
Amount of colibacillus group bacteria (coli-form
microorganisms), i.e. CBGB index, CFU /l
Amount of thermostable colibacilli (fecal coliforms), i.e. FC index, CFU /100 ml
Amount of pathogenic microorganisms, CFU /l
Amount of coli-phages, PFU /l
Parasitologic
Amount of pathogenic intestinal protozoa (cells,
cysts) in 25 l of water
Amount of intestinal helminths (cells, roes, larvae) in
25 l of water
Sanitary rules and
norms (SSRandN)
Maximum 100*
Maximum 3**
Absence ***
Absence ***
Absence ***
Absence
Absence
Children from a certain township present with brittle teeth, malocclusion, dental enamel
erosions, and dental pigmentation that looks life yellow-brown spots. What is the likely
cause of this presentations?
A. High level of nitrates
B. Low level of sulfates in water
C. High level of fluorine in water
D. High level of sulfates in water
E. Low level of fluorine in water
ANSWER: C
The "very mild" (and most common) form of fluorosis, is characterized by
small, opaque, "paper white” areas scattered irregularly over the tooth, covering
less than 25% of the tooth surface.
Severe fluorosis is characterized by brown discoloration and discrete or
confluent pitting; brown stains are widespread and teeth often present a
corroded-looking appearance.
Some of the population of a city district have uneven teeth color. The individuals have
white spots, transverse brown stripes on the incisors. Occurrence of these symptoms is
associated with the quality of drinking water from a deep well. Which of the following
components of water can be the cause of the disease?
A.F
B.Ca
C.Mg
D.J
E.Fe
ANSWER: A
Caries morbidity rate is 89% among residents of a community. It is determined that
fluorine content in water is 0,1 mg/l. What preventive measures should be taken?
A. Water fluorination
B. Tooth brushing
C. Fluorine inhalations
D. Sealant application
E. Introduce more vegetables to the diet
ANSWER: A
In pediatric clinic, located in a rural area, there are 9 children, who simultaneously fell
ill. The following signs were detected: low physical activity, acrocyanosis of the
nasolabial triangle and fingertips, mucosal cyanosis, tachycardia, dyspnea. It was
determined that all the sick children were fed with a formula that was dissolved in the
water taken from a dug well. Laboratory analysis revealed high levels of
methemoglobin in the blood of the children. These sings can be caused by increased
content of a certain element in the water. Name this element.
A. Selenium
B. Lead
C. Methylmercury
D. Nitrates
E. Sulfates
ANSWER: D
Maximum permissible limit 50 mg /l
Examination of a group of persons living on the same territory revealed the following
common symptoms: dark-yellow pigmentation of the tooth enamel, diffuse osteoporosis of
bone apparatus, ossification of ligaments and joints, functional disorders of the central
nervous system. This condition may be caused by the excessive concentration of the
following microelement in food or drinking water:
A. Fluorine
B. Copper
C. Nickel
D. Iodine
E. Cesium
ANSWER: A
According to the report of water quality control, drinking city water has the following
characteristics:
turbidity 1,5 mg/m3, odour 3 points, metallic taste 2 points, pale yellow
colour, colour index 20o, temperature 12o. Which of these factors doesn’t comply with
hygienic requirements?
A. Odour
B. Turbidity
C. Colour index
D. Temperature
E. Taste
ANSWER: A
A military unit stopped for 3-day’s rest in inhabited locality after a long march. The
sanitary-epidemiological reconnai-ssance found several water sources. It is
necessary to choose the source complyi-ng with the hygienic standards for potable
water in the field
A. Artesian well water
B. Spring water
C. River water
D. Rain water
E. Water from melted snow
ANSWER: A
A mineshaft is situated on the territory of homestead land, it is 20 m away from
the house, 10 m - from the toilet and 15 m - from the neighbour’s house.
What is the smallest distance that, according to the sanitary code, should be
established between the well and the source of probable water pollution?
A. 30 m
B. 25 m
C. 20 m
D. 15 m
E. 10 m
ANSWER: A