The transparency of water depends on the amount of mechanical suspended solids and chemical impurities contained in it. Turbid water is always suspicious in epizootic and sanitary terms. There are several methods for determining the transparency of water.

comparison method. The test water is poured into one cylinder made of colorless glass, and distilled water is poured into the other. Water can be rated as clear, slightly transparent, slightly opalescent, opalescent, slightly turbid, turbid, and highly turbid.

disk method. To determine the transparency of water directly in the reservoir, a white enameled disk is used - the Secchi disk (Fig. 2). When the disk is immersed in water, the depth at which it ceases to be visible and at which it becomes visible again when removed is noted. The average of these two values ​​shows the transparency of the water in the reservoir. In clear water, the disk remains visible at a depth of several meters; in very turbid water, it disappears at a depth of 25-30 cm.

Font method (Snellen). More accurate results are achieved using a flat-bottomed glass calorimeter (Fig. 3). The calorimeter is installed at a height of 4 cm from the standard font No. 1:

The investigated water after shaking is poured into the cylinder. Then they look down through the column of water at the font, gradually releasing water from the calorimeter tap until it becomes possible to clearly see font No. 1. The height of the liquid in the cylinder, expressed in centimeters, is a measure of transparency. Water is considered transparent if the font is clearly visible through a column of water of 30 cm. Water with a transparency of 20 to 30 cm is considered slightly cloudy, from 10 to 20 cm - cloudy, up to 10 cm is unsuitable for drinking purposes. Good clear water after standing does not precipitate.

ring method. Water transparency can be determined using a ring (Fig. 3). To do this, use a wire ring with a diameter of 1-1.5 cm and a wire cross section of 1 mm. Holding the handle, the wire ring is lowered into the cylinder with the investigated water until its contours become invisible. Then, with a ruler, measure the depth (cm) at which the ring becomes clearly visible when removed. An indicator of acceptable transparency is considered to be 40 cm. The data obtained “by the ring” can be converted into indications “by the font” (Table 1).

Table 1

Translation of water transparency values ​​"on the ring" to the value "on the font"

The transparency of water in hydrology and oceanology is the ratio of the intensity of light passing through a layer of water to the intensity of light entering the water. Water transparency is a value that indirectly indicates the amount of suspended particles and colloids in water.

The transparency of water is determined by its selective ability to absorb and scatter light rays and depends on the surface illumination conditions, changes in the spectral composition and attenuation of the light flux, as well as the concentration and nature of living and inanimate suspension. With high transparency, the water acquires an intense blue color, which is characteristic of the open ocean. In the presence of a significant amount of suspended particles that strongly scatter light, the water has a blue-green or green color, characteristic of coastal areas and some shallow seas. At the confluence of large rivers carrying a large number of suspended particles, the color of the water takes on yellow and brown hues. River runoff, saturated with humic and fulvic acids, can cause the dark brown color of sea water.

The transparency (or light transmission) of natural waters is due to their color and turbidity, i.e. the content in them of various colored and suspended organic and mineral substances.

Determination of water transparency is a mandatory component of monitoring programs for the state of water bodies. Transparency is the property of water to let light rays through. Reducing the light flux reduces the efficiency of photosynthesis and, consequently, the biological productivity of watercourses.

Even the purest, free of impurities, waters are not absolutely transparent and completely absorb light in a sufficiently thick layer. However, natural waters are never completely pure - they always contain dissolved and suspended substances. Maximum transparency is observed in winter period. With the passage of the spring flood, transparency noticeably decreases. The minimum transparency values ​​are usually observed in summer, during the period of mass development ("blooming") of phytoplankton.

For Belarusian lakes with a natural hydrochemical regime, the transparency values ​​(according to the Secchi disk) vary from several tens of centimeters

up to 2-3 meters. In places where wastewater enters, especially during unauthorized discharges, transparency can be reduced to several centimeters.

Water, depending on the degree of transparency, is conventionally divided into clear, slightly turbid, medium turbidity, turbid, very turbid (Table 1.4). The measure of transparency is the height of the cable of a certain size Secchi disk lowered into the water.

Table 1.4

Characteristics of waters in terms of transparency

Conclusion: Lakes - reservoirs occupying a natural depression on the earth's surface. There are a number of classifications of reservoirs with stagnant water, the main indicators of pollution of which are the degree of saprobity and trophic status. To classify lakes as one or another water body in terms of saprobity and trophicity, their physical indicators and species composition macrozoobenthos.

The transparency of Lake B. Miassovo for most of the ice-free period fluctuates within 1 3-5 m and only shortly before freezing rises to 6.5 m. In May, after the ice has melted, and in autumn, starting from the end of August, the lowest water transparency is noted. The minimum transparency in spring and autumn depends on the mass development and death of phytoplankton and the entry of allochthonous suspensions into the water during ice melting and intense precipitation. An important role is played by spring and autumn homothermy, which contributes to the mixing and removal of precipitation into the water column.[ ...]

The transparency of water depends on its color and the presence of suspended matter. . substances.[ ...]

The transparency of water is determined using a glass cylinder with a polished bottom (Snellen cylinder). The cylinder is graduated in height in centimeters, starting from the day. The height of the graduated part is 30 cm.[ ...]

The transparency of water for ultraviolet rays is one of its most important properties, thanks to which the decomposition of chemicals in all areas of the environment is possible. Waves of effective length (approximately 290 nm), entering the atmosphere, quickly lose energy and become almost inactive (450 nm). However, such radiation is sufficient to break a number of chemical bonds.[ ...]

The transparency of water depends on the amount of suspended and dissolved mineral and organic substances in it, and in summer - on the development of algae. Closely related to transparency is the color of water, which often reflects the content of dissolved substances in it. Transparency and color of water are important indicators of the state of the oxygen regime of a reservoir and are used to predict fish kills in ponds.[ ...]

The transparency of water determines the amount of sunlight entering the water, and hence the intensity of the photosynthesis process in aquatic plants. In muddy water bodies, photosynthetic plants live only at the surface, and in clear water they penetrate to great depths. The transparency of water depends on the amount of mineral particles suspended in it (clay, silt, peat), on the presence of small animals and plant organisms.[ ...]

The transparency of water is one of the indicative signs of the level of development of life in reservoirs and along with thermals. Chemistry and circulation conditions constitute the most important ecological factor.[ ...]

Clear water and bright sunshine call for baits with a matte surface or a dull color. The splendor of the bait, which scares away fish, can be easily and quickly extinguished by holding it over a piece of burning birch bark.[ ...]

Water transparency ranges from 1.5 m in summer to 9.5 m in winter, and it is much higher near deep lakes.[ ...]

The transparency of water depends on the amount and degree of dispersion of substances suspended in water (clay, silt, organic suspensions). It is expressed in centimeters of water column, through which lines 1 l m thick are visible, forming a cross (definition by “cross”) or font No. 1 (according to Snellen or according to “font”).[ ...]

The transparency of water is one of the main criteria for judging the state of the reservoir. It depends on the amount of suspended particles, the content of dissolved substances and the concentration of phyto- and zooplankton. Affects the transparency and color of water. The closer the color of water to blue, the more transparent it is, and the more yellow, the less transparent it is.[ ...]

Water transparency is a measure of self-purification of open water bodies and a criterion for the efficiency of treatment facilities. For.the consumer, it serves as an indicator of the good quality of water.[ ...]

The color of the water in the lake experiences seasonal fluctuations and is not uniform in various parts lakes, as well as transparency. So, in the open part of the lake. Baikal, with high transparency, the water has a dark blue color, in the area of ​​\u200b\u200bthe Selenginsky shallow water it is grayish-green, and near the river. Selengi - even brown. In Lake Teletskoye, in the open part, the color of the water is green, and near the shores it is yellow-green. The mass development of plankton not only reduces transparency, but also changes the color of the lake, giving it the color of organisms in the water. During flowering, green algae color the lake in green color, blue-greens give it a turquoise color, diatoms yellow, and some bacteria color the lake crimson and red.[ ...]

Less transparent water heats up more near the surface (in the case when there is no intensive mixing of water due to wind or current). More intense heating serious consequences. Since warm water has a lower density, the heated layer seems to "float" on the surface of cold and therefore heavier water. This effect of stratification of water into almost non-mixing layers is called the stratification of a water body (usually a reservoir - a pond or lake).[ ...]

Usually water transparency is correlated with biomass and plankton production. In conditions of different natural areas moderate pops, the lower the transparency, the better, on average, the plankton is developed, i.e. there is a negative correlation. This was pointed out by researchers at the end of the last and the beginning of this century. Further, the study of water transparency makes it possible to delineate the distribution of water masses of various genesis and indirectly judge the distribution of currents in reservoirs with slow water exchange [Butorin, 1969; Rumyantsev, 1972; Bogoslovsky et al., 1972; Vologdin, 1981; Ayers et a.l., 1958].[ ...]

Solid particles and plankton suspended in the water, as well as snow and ice in winter, make it difficult for light to penetrate the water. Only 47% of light rays penetrate through a meter layer of distilled water, and almost no light passes through dark water (for example, marsh lakes) to a depth of more than one meter. Approximately 50 cm ice transmits less than 10% of the light. And if the ice is covered with snow, then only 1% of the light reaches the water. Of the light rays, green and blue penetrate deepest into transparent water.[ ...]

Studies of water transparency of the lake. B. Miassovo were carried out in 1996-1997, the results are presented in fig. 11. Transparency measurements were made on the main measurement vertical using the standard Secchi disk method. The frequency of measurements is monthly.[ ...]

To determine the transparency of water directly in the reservoir, the Secchi method is used: a white enameled disk is lowered on a string into the reservoir; the depth in centimeters is noted at the following moments; a) when the visibility of the disk disappears and b) when the visibility of it appears when it is raised. The average of these two observations determines the transparency of the water in the reservoir.[ ...]

The conditions of illumination in water can be very different and depend, in addition to the strength of illumination, on the reflection, absorption and scattering of light, and many other factors. An essential factor determining the illumination of water is its transparency. The transparency of water in various reservoirs is extremely diverse, ranging from the muddy, coffee-colored rivers of India, China and Central Asia, where an object immersed in water becomes invisible as soon as it is covered with water, and ending with the transparent waters of the Sargasso Sea (transparency 66.5 m), central part Pacific Ocean(59 m) and a number of other places where the white circle - the so-called Secchi disk, becomes invisible to the eye only after diving to a depth of more than 50 m. Naturally, the lighting conditions in different water bodies located even at the same latitudes on the same same depth, are very different, not to mention different depths, because, as you know, with depth, the degree of illumination decreases rapidly. So, in the sea off the coast of England, 90% of the light is absorbed already at a depth of 8-9 m.[ ...]

In the seasonal fluctuations in the transparency of lake waters, winter and autumn maxima and spring and summer minimums are outlined. Sometimes the summer minimum shifts by autumn months. In some lakes, the lowest transparency is due to a large amount of sediment delivered by tributaries during floods and rain floods, in others - the massive development of zoo- and phytoplankton ("blooming" of water), in others - the accumulation of organic substances.[ ...]

The amount of coagulant introduced into the water (mg / l, mg-eq / l, g / m3 or g-eq / m3) is called the coagulant dose. The minimum concentration of coagulant that corresponds to the best clarification or discoloration of water is called the optimal dose. It is determined empirically and depends on the salt composition, hardness, alkalinity of water, etc. The optimal dose of coagulant is considered to be its minimum amount, which during trial coagulation gives large flakes and maximum water transparency after 15-20 minutes. For aluminum sulfate, this concentration usually ranges from 0.2 to 1.0 meq / l (20-100 mg / l) During the flood, the dose of coagulant is increased by approximately 50% - At water temperatures below 4 ° C, the dose of aluminum coagulant is increased almost twice.[ ...]

With the content of suspended solids in the source water up to 1000 mg/l and color up to 150 degrees, clarifiers provide water transparency of at least 80-100 cm on the cross and color not higher than 20 degrees of the platinum-cobalt scale. In this regard, in some cases, clarifiers are used without: filters. Clarifiers are designed round (diameter no more than 12-14 m) or rectangular (the area does not exceed 100-150 m2). Usually clarifiers work without flocculation chambers.[ ...]

Biological processes are an important factor determining the transparency of water in stagnant water bodies. Water transparency is closely related to biomass and plankton production. The better developed plankton, the less water transparency. Thus, the transparency of water can characterize the level of development of life in a reservoir. Transparency has great importance as an indicator of the distribution of light (radiant energy) in the water column, on which photosynthesis and the oxygen regime of the aquatic environment primarily depend.[ ...]

Most of our planet is covered with water. The aquatic environment is a special habitat, since life in it depends on the physical properties of water, primarily on its density, on the amount of oxygen and carbon dioxide dissolved in it, on the transparency of water, which determines the amount of light at a given depth. In addition, the speed of its flow, salinity are important for the inhabitants of the water.[ ...]

For thousands of years, people have tried to get clean water. Several centuries ago, the main efforts of people were aimed at obtaining clear water. Thus, for example, water purification in the early US water systems was mainly to remove silt, and in many cases the reason for the creation of the first public water systems was simply the desire to eliminate dirty channels along streets and roads. Thus, almost until the beginning of the XX century. the danger of contamination through water was not the main argument in favor of establishing public water supply systems. Prior to 1870, there were no water filtration plants in the United States. In the 70s of the XIX century, coarse sand filters were built on the river. Poughkeepsie and R. Hudson, pcs. New York, and in 1893 the same filters were built in Lawrence, pc. By 1897, more than 100 fine sand filters were built, and by 1925 - 587 fine sand filters and 47 coarse sand filters, providing treatment of 19.4 million m3 of water.[ ...]

Primary phytoplankton production correlates with water transparency (Vinberg, 1960; Romanenko, 1973; Baranov, 1979, 1980, 1981; Bouillon, 1979, 1983; Voltenvveider, 1958; Rodhe, 1966; Ahlgren, 1970]. Correlation coefficients d) between transparency , phytoplankton biomass and chlorophyll a content are quite reliable and amount to r = -0.48-0.57 for water bodies of the BSSR [Ikonnikov, 1979]; Estonia - r = -0.43-0.60 [Milius, Kieask, 1982], Poland - r - -0.56, ponds of the state of Alabama r = -0.79 [Almaran, Boyd, 1978]. The average values ​​of the content of chlorophyll "a" and the transparency of water on a white disk for deep lakes are given in Table. 64.[ ...]

An indirect method for determining the transparency of water (optical density) is widely used. Optical density is determined by optoelectric devices - colorimeters and nephelometers, using calibration graphs. A number of photocolorimeters for general industrial purposes (FEK-56, FEK-60, FAN-569, LMF, etc.) are produced, which are used at water treatment plants. However, this type of instrumental control over the content of suspended solids in water is associated with large labor and time costs for the collection and delivery of water samples.[ ...]

Comparison of the zooplankton biomass per unit area with transparency shows that in the water bodies of the tundra, northern and middle taiga, with an increase in the transparency value, the zooplankton biomass per unit area decreases. In lakes of the northern taiga, zooplankton biomass from 7.5 g/m1 with water transparency less than 1 m to 1.4 g/m3; with a water transparency of more than 8 m, in the lakes of the middle tzygi, respectively, from 5.78 g/m2 to 2.81 g/m2.[ ...]

Primary lakes, which arose when natural basins were filled with water, are gradually populated by plants and animals. Young lakes have clean clear water, their bottom is covered mainly with sand, overgrowing is insignificant. Such lakes are called oligotrophic (from the Greek words oligos - "small", and trophe - "food"), i.e. malnourished. Gradually, these lakes are saturated with organic matter. Dying aquatic organisms sink to the bottom, forming silty bottom sediments, and serve as food for bottom-dwelling animals. accumulate in water organic matter secreted by animals and plants and remaining after their death. Increase in the amount in the reservoir nutrients stimulates further development life in a pond.[ ...]

The upper pool of the Uglich hydroelectric power station turned out to be polluted. Despite the high water transparency of 130 cm, filter-feeding invertebrates had a very low density, there was no zebra mussel.[ ...]

For the preparation of high quality masonry mortar 1, the hardness of the water is of great importance. In order to determine the hardness or softness of water at home, heating it dissolves a small amount of crushed soap in it, after cooling the solution remains transparent - the water is soft, in; With some water, the solution becomes covered with a film when cooled. Except in hard water, soap suds do not whip.[ ...]

The average values ​​of ichthyomass in the lakes of the middle taiga zone and in the lakes of the mixed forest zone decrease with increasing transparency (Table 66).[ ...]

Characteristic of rhodanide compounds is a very slight effect on the organoleptic properties of water. Even at concentrations greater than 100 mg/l, none of the testers indicated any noticeable change in the odor of the water; there was no change in color, and water transparency. The ability of thiocyanates to add flavor to water is somewhat more pronounced.[ ...]

The Ukhta River: an average depth of 5 m, a channel with a large number of riffles, on which communities of the genus Sparganium develop. The transparency of the water is up to 4 m, the bottom is silted sands, pebbles, silted pebbles. The temperature in July-August reaches 18°C. Colva River: depth up to 7 m, water transparency up to 0.7 m, sandy bottom, temperature in July-August does not exceed 12°C.[ ...]

The photoelectronic installation for filter washing control (AOV-7 index) operates on the principle of attenuation of the light flux in a layer of water containing suspended solids. The absorption of light is fixed by a photocell connected to an indicating electrical measuring device of the MRSchPr type. The use of a simple phototurbidimetric technique for measuring the transparency of water in this case is acceptable, since the filters are always washed with purified water with a low, almost constant, water color. The primary sensor consists of a flow cell, a hermetically sealed chamber for a photocell, a chamber with an electric light bulb, and an electromagnet with hair brushes that periodically clean the cell window. Secondary device indicating the type of MRSchPr or EPV. Their positional regulators are used to stop washing the filters when the specified water transparency is reached.[ ...]

In general, it is impossible to put an end to the definition of the concept of a small river. Some works are based on the study of the level of development of aquatic organisms. So, Yu.M. Lebedev (2001, p. 154) wrote: “A small river is a watercourse with water transparency to the bottom, the absence of true phytoplankton and adult fish, except for the low-growing local populations of roach, perch, minnow (trout for mountain rivers and grayling for Siberian), and the predominance of animal scrapers in the benthos.”[ ...]

The amount of incident solar radiation absorbed earth's surface, is a function of the absorptive capacity of that surface, i.e., depends on whether it is covered by soil, rock, water, snow, ice, vegetation, or something else. Loose cultivated soils absorb much more radiation than ice or highly reflective rocks. The transparency of water increases the thickness of the absorbing layer, and thus a given water column absorbs more energy than the same thickness of opaque land.[ ...]

Natural E.e. takes place on a millennium scale, it is currently suppressed by anthropogenic EE associated with human activity. EUTROPHICATION (E.) - a change in the state of the aquatic ecosystem as a result of an increase in the concentration of nutrients in the water, usually phosphates and nitrates. With E.v. in plankton, cyanobacteria and algae develop in very large quantities, the transparency of water decreases sharply, and the decomposition of dead phytoplankton consumes oxygen in the near-bottom zone. This sharply impoverishes the species composition of the ecosystem, almost all fish species die, plant species adapted to life in conditions disappear. pure water(salvinia, amphibian buckwheat), and duckweed and hornwort grow en masse. E. is the scourge of many lakes and reservoirs located in densely populated areas.[ ...]

Photo-synthetic release of oxygen occurs when carbon dioxide is taken up by aquatic vegetation (attached, floating plants and phytoplankton). The process of photosynthesis proceeds the more intensively, the higher the water temperature, the more biogenic (nutrient) substances (compounds of phosphorus, nitrogen, etc.) in the water. Photosynthesis is possible only in the presence of sunlight, since in it, along with chemicals light photons are involved (photosynthesis occurs even in non-solar weather and stops at night). The production and release of oxygen occurs in the surface layer of the reservoir, the depth of which depends on the transparency of the water (for each reservoir and season it can be different - from a few centimeters to several tens of meters).[ ...]

This happened with the problem of the color of the sea: in 1921, the origin of the color of the sea was explained simultaneously by Shuleikin (in Moscow) and C. Raman (in Calcutta). The area of ​​work of both authors was reflected in the interpretation of the issue: Raman, who dealt with the crystal clear waters of the Bay of Bengal, gave a theory of the color of the sea, based on the concept of purely molecular scattering of light in water. Therefore, his theory is inapplicable to seas that exhibit strong scattering of light in water.[ ...]

Vaamochka belongs to the firth type of lakes, its depth does not exceed 2-3 m, water transparency is low. Pekulneiskoye is of the fiord type, in the central part of the depth varies from 10 to 20 m, and in the hall. Kakanauts fluctuate within 20-30 m. The lakes Vaamochka and Pekulneyskoye are connected to each other by channels, and through a common mouth, usually washed out in winter, with the Bering Sea. Compared to lake Vaamochka, the role of Pekulneisky in regulating the flow is much higher, since its area exceeds the area of ​​\u200b\u200bthe lake. Vamochka more than four times, and the catchment area is more than half of the total basin area of ​​the system. In this regard, from the beginning of the spring flood to the opening of the mouth, the current in the channels is directed from the lake. Vaamochka to Pekulneyskoye, and after the opening of the mouth, Pekulneyskoye Lake is more influenced by sea tides.[ ...]

In general, the requirements for environmental safety of water resources management are based on the implementation of water use plans developed taking into account the indicated factors and processes that describe the state of aquatic ecosystems. The defining indicators of the state of aquatic ecosystems are: water purity class, saprobity index, species diversity index, and gross phytoplankton production [Assessment of the state..., 1992]. Parameters related to water quality also include such indicators as water transparency, pH value, content of nitrate ions and phosphate ions in water, electrical conductivity, biochemical oxygen demand, etc.[ ...]

The need of ponds for fertilizer is determined by biological, organoleptic and chemical methods. The biological method consists in determining the intensity of photosynthesis in algae by observing the growth of algae in flasks, into which different amounts of fertilizers are applied and the development of algae in them is taken into account. More simply, the need for fertilizers can be determined by the transparency of the water. Fertilizers are applied when the water transparency is more than 0.5 m. The most accurate method is the chemical analysis of water for the content of nitrogen and phosphorus and bringing them to a certain norm.[ ...]

As a result of these factors, the upper layer of the ocean is usually well mixed. It is called so - mixed. Its thickness depends on the season, wind strength and geographical area. For example, in summer in calm weather, the thickness of the mixed layer in the Black Sea is only 20-30 m. And in the Pacific Ocean near the equator, a mixed layer with a thickness of about 700 m was discovered (by an expedition on the research vessel "Dmitry Mendeleev"). From the surface to a depth of 700 m there was a layer of warm and clear water with a temperature of about 27 ° C. This region of the Pacific Ocean is similar in its hydrophysical properties to the Sargasso Sea in the Atlantic Ocean. In winter, the mixed layer on the Black Sea is 3-4 times thicker than the summer layer, its depth reaches 100-120 m. Such a large difference is explained by intense mixing in winter: the stronger the wind, the greater the excitement on the surface and the stronger the mixing. Such a jump layer is also called seasonal, since the depth of the layer depends on the season of the year.[ ...]

For hydrobiology, it is important that the size classification of streams reflect the ecosystem components. From this point of view, foreign studies are extremely interesting, demonstrating that in watercourses of a low order, a transit character prevails, and in more major rivers- accumulative. This approach to classification, although attractive, is not very operational. It has been established that in the upper reaches of the river network, among benthic animals, scrapers predominate, and below they are replaced by gatherers. It is also known that if water transparency exceeds the maximum depth of rivers, then periphyton algae develop in such watercourses, and true plankton is poorly represented. With increasing depths, the ecosystem acquires a planktonic character. Apparently, the latter criterion can be chosen as the boundary between small and larger watercourses. Unfortunately, it is necessary but not sufficient. So, for example, the Zeya in the upper reaches, according to its hydrooptical characteristics, can be classified as small, and its tributary in this section of the Arga, due to the high coloration of the water, is not transparent to the bottom. Therefore, the criterion must be supplemented. As you know, fish live in streams, the depth of which exceeds a certain minimum. For trout ego 0.1 m, for grayling - 0.5, for barbel - 1 m.

Transparency of water according to the Secchi disk, according to the cross, according to the font. Turbidity of water. The smell of water. Water color.

Water transparency

There are suspended solids in the water, which reduce its transparency. There are several methods for determining the transparency of water.

1. According to the disk of Secchi. To measure the transparency of river water, a Secchi disk with a diameter of 30 cm is used, which is lowered on a rope into the water, attaching a weight to it so that the disk goes vertically down. Instead of a Secchi disk, you can use a plate, lid, bowl, placed in a grid. The disk is lowered until it is visible. The depth to which you lowered the disk will be an indicator of the transparency of the water.
2. By the cross. Find the maximum height of the water column, through which the pattern of a black cross is visible on a white background with a line thickness of 1 mm, and four black circles with a diameter of 1 mm. The height of the cylinder in which the determination is carried out must be at least 350 cm. At the bottom of it is a porcelain plate with a cross. The bottom of the cylinder should be illuminated with a 300W lamp.
3. By font. A standard font is placed under a cylinder 60 cm high and 3-3.5 cm in diameter at a distance of 4 cm from the bottom, the test sample is poured into the cylinder so that the font can be read, and the maximum height of the water column is determined. The method for quantitative determination of transparency is based on determining the height of the water column, at which it is still possible to visually distinguish (read) a black font 3.5 mm high and a line width of 0.35 mm on a white background or see an adjustment mark (for example, a black cross on white paper) . The method used is unified and complies with ISO 7027.

Turbidity of the water

Water has increased turbidity due to the content of coarse inorganic and organic impurities in it. The turbidity of water is determined by the gravimetric method, and by a photoelectric colorimeter. The weight method is that 500-1000 ml of turbid water is filtered through a dense filter with a diameter of 9-11 cm. The filter is preliminarily dried and weighed on an analytical balance. After filtering, the filter with sediment is dried at a temperature of 105-110 degrees for 1.5-2 hours, cooled and weighed again. The amount of suspended solids in the test water is calculated from the difference between the masses of the filter before and after filtration.

In Russia, the turbidity of water is determined photometrically by comparing samples of the studied water with standard suspensions. The measurement result is expressed in mg / dm 3 using the main standard suspension of kaolin (turbidity for kaolin) or in MU/dm 3 (turbidity units per dm 3) when using formazin stock standard suspension. The last unit of measurement is also called the Turbidity Unit. according to Formazin(EMF) or in Western terminology FTU (formazine Turbidity Unit). 1FTU=1EMF=1EM/dm 3 .

IN Lately The photometric method for measuring turbidity by formazin has been established as the main one all over the world, which is reflected in the ISO 7027 standard (Water quality - Determination of turbidity). According to this standard, the unit of measure for turbidity is FNU (formazine Nephelometric Unit). Agency for Protection Environment USA (U.S. EPA) and World Organization The World Health Organization (WHO) uses the Nephelometric Turbidity Unit (NTU) for turbidity.

The relationship between the basic turbidity units is as follows:

1 FTU(EMF)=1 FNU=1 NTU

WHO does not standardize turbidity according to indications of health effects, however, from the point of view of appearance recommends that turbidity be no higher than 5 NTU (nephelometric turbidity unit) and, for decontamination purposes, no more than 1 NTU.

Determining the smell of water

Odors in the water can be associated with the vital activity of aquatic organisms or appear when they die - these are natural odors. The smell of water in a reservoir can also be caused by sewage effluents entering it, industrial effluents are artificial odors. First, a qualitative assessment of the smell is given according to the relevant features:

• marsh,
• earthy,
• fish,
• putrefactive,
• aromatic,
• oil, etc.

The strength of the smell is evaluated on a 5-point scale. The flask with a ground stopper is filled 2/3 with water and immediately closed, shaken vigorously, opened and the intensity and nature of the odor are immediately noted.

Determination of water color

A qualitative assessment of the color is made by comparing the sample with distilled water. To do this, separately investigated and distilled water is poured into glasses made of colorless glass, viewed from above and from the side against a white sheet in daylight, color is evaluated as an observed color, in the absence of color, the water is considered colorless.

Transparency of sea water- an indicator characterizing the ability of water to transmit light rays. Depends on the size, quantity and nature of suspended solids. To characterize the transparency of water, the concept of "relative transparency" is used.

Story

For the first time, the degree of transparency of sea water was able to determine the Italian priest and astronomer named Pietro Angelo Secchi in 1865 using a disk with a diameter of 30 cm, lowered into the water on a winch from the shady side of the ship. This method was later named after him. IN this moment there are and are widely used electronic devices for measuring the transparency of water (transmissometers)

Methods for determining the transparency of water

There are three main methods for measuring water transparency. All of them involve the determination of the optical properties of water, as well as taking into account the parameters of the ultraviolet spectrum.

Areas of use

First of all, calculations of water transparency are an integral part of research in hydrology, meteorology and oceanology, the transparency / turbidity index determines the presence of undissolved and colloidal substances of inorganic and organic origin in water, thereby affecting marine environment pollution, and also makes it possible to judge accumulations plankton, turbidity content in water, silt formation. In shipping, the transparency of sea water can be a determining factor in the detection of shallow water or objects capable of causing damage to the vessel.

Sources

• Mankovsky V. I. An elementary formula for estimating the light attenuation index in sea water from the visibility depth of a white disk (Russian) // Oceanology. - 1978. - T. 18 (4). - S. 750–753.
• Smith, R. C., Baker, K. S. Optical properties of the clearest natural waters (200-800 nm)
• Gieskes, W. W. C., Veth, C., Woehrmann, A., Graefe, M. Secchi disc visibility world record shattered
• Berman, T., Walline, P. D., Schneller, A. Secchi disk depth record: A claim for the eastern Mediterranean
• Guidelines. Determination of temperature, smell, color (color) and transparency in wastewater, including treated wastewater, storm water and melt water. PND F 12.16.1-10