Zhukov V., Zaytseva O., Telegin V., Miroshnichenko N.,
Risovanaya L., Chubukin A.
Kharkiv National Medical University, Kharkiv, Ukraine
Influence of some simple ethers on
the water organoleptic properties and sanitary regime of water reservoirs
Chemical
compounds entering the water reservoirs from industry sewage more or less can
give a negative effect on organoleptic properties of water and process of
natural water self-cleaning. The deterioration of the water aesthetic
parameters is the most common cause of population abstinence from water use; it
always leads to water use limitation. Polyoxypropylenpolyols P-5003-AC,
P-373-2-20, P-294-2-35 are widely used in many sectors of the economy as
intermediate and final products. In industrial production of these compounds a
large amount of sewage is produced (50 m3/ton of finished
product); this water inevitably enter the water reservoirs creating serious
difficulties in population supply with good quality water.
The
possibility of transformation and the transformation of each individual
substance to a certain extent depends on the stability of its forms in an
aqueous medium and is defined both by properties of the xenobiotic and by the
aquatic environment. The leading and reliable preventive measure limiting the
entry of xenobiotics in the environment, and particularly in water sources is
their hygienic regulation and substantiation of the forecast of the potential
hazard for warm-blooded animals, and water reservoirs.
The aim of this research was to
examine the effect of polyoxypropylenpolyols P-5003-AC, P-373-2-20, P-294-2-35
on the organoleptic properties of water, sanitary regime of water reservoirs,
and to substantiate the threshold concentrations which do not violate mentioned
indicators.
Material and research methods. As objects of
investigation were: polyoxypropylenpolyols M.M 5000 (P-5003-AC) and M.M 370
(P-373-2-20), as well as oxypropylene amine M.M 290 (P-294-2-35). These
substances are viscous liquids with regulated physical and chemical properties,
well-soluble in water and organic solvents. The ability of xenobiotics
transformation and their stability was investigated with help of direct method
(gas-liquid chromatography) and indirect methods (changes in the observation
dynamics of organoleptic and common sanitary indices). The substances effect on
water organoleptic properties was investigated in compliance with the Ukrainian
National Standards. Odor and taste were determined by a team-based approach in
a well ventilated room. Spring water devoid of odor and flavor was used as
diluent water. Different concentrations were prepared by repeated dilution of
the initial solution. Odor provoking under solution chlorination was done by
doses of active chlorine 0.1, 1.0, 2.0 mg/l. Investigations were performed at
aqueous solutions temperature 20 and 60°C. Compounds effect on the color and
transparency was determined in flat-bottomed cylinders made of colorless glass:
the color of water – by comparing the solutions on a white background with the
original water, and transparency – by mean of reading Snellen’s font through a
column of water solution. Foaming properties were researched according to the
Ukrainian National Standards, the threshold concentration for foaming was
determined by shaking. The influence of substances on the sanitary regime of
water reservoirs was studied by the following indices: biochemical consumption
of oxygen (BCO5, BCO20),
dissolved oxygen content (O2), pH of model reservoir water in
dynamics of observation ; quantification of ammonia NH3, nitrites
(NO2), nitrates (NO3), development and reproduction of
Daphnia, saprophytic and conditionally pathogenic microorganisms, viruses, and
algae. Standard methods underlie determination of the xenobiotics effect on the
sanitary regime of water reservoirs.
Results of researches and their discussion. Studies of the
xenobiotics effect on the organoleptic properties of water and its sanitary
regime was started with evaluation of their stability and transformation in the
aquatic environment. During research it was discovered that substances can be
unchanged for a long time in aqueous solutions. In exposure of solutions with
initial concentration of substances 4 g/l on the 6th month of
monitoring the xenobiotics content exceeded 80% in all cases. The half-life of
substances under exposure of aqueous solutions during a year was not
established with help of direct method of gas-liquid chromatography. Rate of
hydrolytic degradation of xenobiotics depended on their initial concentration.
Thus, when the initial concentration of the compounds was 10 mg/l the content
of xenobiotics in the solutions on the 30th day was 50-65%, whereas at 1000
mg/l it was more than 95%. The high stability of the xenobiotics was confirmed
by indirect methods: evaluation of taste, odor, foaming, and biological tests
on Daphnia. For interpretation of the results we used the following grading of
estimate for substances stability:
short-stable:
original flavor (odor) at 2 points disappears on 1st day, and at 5
points – not later than on 6th days;
relatively
stable: the original flavor (odor) vanishes on 2-3rd day, at 5
points – on 6-7th day;
highly
stable: the original flavor (smell) at 2 points can not be detected on the 4-5th
day, at 5 points – more than on 10th days, and if the original
flavor (odor) is not reduced during 7 days and more.
In 10
days of aqueous solutions exposure the presence of bitter-viscous taste, oil
products odor, and foaming properties at the level of practical threshold were
revealed; it confirmed the high stability of xenobiotics and the need of
effective degree of purification of sewage containing these compounds. Among
the products of the hydrolytic oxidation of xenobiotics hydrocarbons,
aldehydes, ketones, alcohols, ethers, were revealed by gas-liquid chromatography;
it confirmed the free radical mechanism underlying the polyoxypropylenpolyols
transformation. Metabolites of the hydrolytic oxidation are much more toxic and
dangerous for warm-blooded animals. They have a polytropic action.
During
research we discovered that compounds at concentrations greater than
50 mg/l are able to give a bitter-viscous taste, oil products odor, and
foaming properties to aqueous solutions. Induction of smells and tastes under
the chlorination of aqueous solutions at the threshold doses (2 points) was not
observed. Limiting organoleptic indicator of hazard is foaming. The threshold
concentrations for this indicator are determined at levels of 1.0,
5.0, and 1.0 mg/l respectively for the P-5003-AC, P-294-2-35, and P-373-2-20
(Table 1).
Table 1
Effect of polyoxypropylenpolyols on organoleptic
properties of water
|
Organoleptic
properties of water |
Threshold
concentrations, mg/l |
||
|
P-5003-AC |
P-373-2-20 |
P-294-2-35 |
|
|
Taste: |
|
|
|
|
1 point |
44.30±3.20 |
45.60±2.70 |
40.60±4.35 |
|
2 points |
59.60±3.40 |
63.70±4.35 |
56.20±2.80 |
|
Odor: |
|
|
|
|
1 point |
39.60±2.50 |
43.40±3.40 |
47.60±4.20 |
|
2 points |
56.30±2.80 |
62.80±3.50 |
65.40±3.60 |
|
Foaming |
1.0 |
5.0 |
1.0 |
|
Transparency |
No effect up to
100 mg/l |
||
|
Color |
No effect up to
100 mg/l |
||
Among
the large variety of negative effects of hazardous substances and of industrial
sewage on water reservoirs a special attention was given to the study of their
influence on the sanitary regime of water reservoirs and water-use conditions.
During researching of the self-purification processes in the model water
reservoirs we revealed that xenobiotics at concentrations more than
20.0 mg/l increase the biochemical consumption of oxygen (BCO5,
BCO20), decrease the dissolved O2 concentration in water,
inhibit accumulation of NH3, nitrites (NO2), nitrates (NO3);
all these indicate the inhibition of organic substances mineralization, the
toxic effect on growth and reproduction of aquatic organisms – Daphnia,
saprophytic and conditionally pathogenic microorganisms, viruses, and
unicellular algae (Table 2). Xenobiotics at concentrations up to 100 mg/l
do not cause violations of the pH limits (6.5-8.5) regulated by the Rules of
surface waters protection from pollutions. Limiting common sanitary indicator
of hazard was determined according to polyoxypropylenpolyols effect on Daphnia
growth and reproduction.
Table 2
Effect of polyoxypropylenpolyols on sanitary regime of
water reservoirs
|
Indicator |
Threshold
concentration, mg/l |
||
|
P-5003-AC |
P-373-2-20 |
P-294-2-35 |
|
|
BCO5 |
20.0 |
40.0 |
40.0 |
|
Î2 |
20.0 |
40.0 |
40.0 |
|
NH3 |
20.0 |
40.0 |
40.0 |
|
NO2 |
20.0 |
40.0 |
40.0 |
|
NO3 |
20.0 |
40.0 |
40.0 |
|
pH |
No effect up to
100 mg/l |
||
|
Pedinomonas
tenuis |
15.0 |
20.0 |
20.0 |
|
Dunaliellasalina |
10.0 |
15.0 |
15.0 |
|
Daphniamagna |
5.0 |
10.0 |
10.0 |
Conclusions
1.
Polyoxypropylenpolyols P-294-2-35, P-373-2-20, and P-5003-AC are highly stable
compounds which can be undergone to hydrolytic oxidation with difficulty. In
the process of their transformation in the aquatic environment they can form
aldehydes, ketones, alcohols, ethers which are more toxic and dangerous to warm
blooded animals; they have a polytropic mechanism of action, can damage all
organs, systems, and functions of the warm-blooded animal organism.
2.
Xenobiotics in concentration more than 50.0 mg/l are able to give a
bitter- viscous taste, oil products odor, and foaming properties to aqueous
solutions. At concentrations up to 100.0 mg/l these substances do not effect on
the color, transparency, and turbidity of water. Limiting organoleptic
indicator of hazard is foaming. Threshold concentrations are determined at
levels 1.0, 5.0, and 1.0 mg/l respectively for the P-5003-AC, P-294-2-35, and
P-373-2-20.
3.
Polyoxypropylenpolyols P-294-2-35, P-373-2-20 and P-5003-AC at concentrations
more than 20.0 mg/l increase the biochemical consumption of oxygen (BCO5, BCO20),
decrease the dissolved O2 concentration in water, and inhibit
accumulation of NH3, nitrites (NO2), nitrates (NO3),
make the toxic effect on growth and reproduction of aquatic organisms –
Daphnia, saprophytic and conditionally pathogenic microorganisms, viruses, and
unicellular algae; all these indicate unfavorable influence of this group of
compounds on the processes of natural self-purification of water. Limiting
common sanitary indicator of hazard was determined according to xenobiotics
effect on Daphnia. Threshold concentrations for this test are determined at
levels 5.0, 10.0, and 10.0 mg/l respectively for P-294-2-35, P-5003-AC,
P-373-2-20.