SU1716400A1 - Method for determining water quality - Google Patents

Abstract

The invention relates to the protection and rational use of reservoirs. The purpose of the invention is to increase express ™, reliability and simplification of the method. A sample of water is taken, the plankton is concentrated by filtration, pigments are extracted with acetone, optical density D of the extract is measured at wavelengths 450.480, 664 nm. Then, the optical density ratio D450 / D480, D480 / D664 is determined. Water quality is judged by a pre-built graphic model. 1 dw., 2 tab. /

Description

The invention relates to the protection and rational use of water bodies, in particular, to methods for assessing the state of water during the flowering period of blue-green algae, which leads to known negative consequences, and can be used in hydrobiology, hydrochemistry, ecology, and development of remote sensing methods. eatrophication of reservoirs, zoning of lakes and reservoirs, monitoring the state of water in places of water use, fish farming, recreation, etc.

To assess the dominance of blue-green algae, a countable-volume method of biomass calculation can be used, which allows determining the contribution of blue-green algae to the total phytoplankton stock. The method is very time consuming and difficult to perform, requires highly skilled.

Closest to the invention is a spectrophotometric method for the determination of phytoplankton pigments, which is used to assess the presence of non-green algae s in relation to chlorophyll b and c to chlorophyll a. The method is based on measuring the optical density of phytoplankton pigment extract in the long-wavelength region at wavelengths of 664, 647 and 630 nm and further calculating the concentrations of chlorophylls a, b, c.

However, this method is used only for the determination of chlorophyll-a. Evaluation of other chlorophylls (b and c) is problematic, especially as assessment of the composition of phytoplankton / To improve the accuracy of determining the concentration of chlorophylls b and c, several analyzes should be made from a single water sample, increase the number of measurements on the instrument, carry out a complex calculation of error-h

about

4 o

about

Stei These techniques significantly increase the cost of working time.

The purpose of the invention is to increase the speed, reliability and simplification of the method.

As a criterion for the dominance of blue-green, the interrelation of optical density ratios of the extract of pigments from plankton at wavelengths of 450.480 and 480, 664 nm is used. This criterion is more reliable because it depends on the ratio of specific absorptions to chlorophylls and carotenoids, which is important for blue-green assessment. In general, the method involves sampling water, concentrating plankton by filtering, removing pigments with acetone, separating the precipitate by centrifuging, measuring the optical density of the extract on any spectrophotometer at 450, 480 and 664 nm, and calculating the optical density ratios at 450, 480 nm and 480, 664 nm, detection using pre-constructed model plots of the degree of dominance of blue-green algae and assessment of the state of water.

The drawing shows model graphs explaining the essence of the method,

In drawing A, a clean zone — the dominance of blue-green is unreliable (less than 50%), biomass does not accumulate, the state of water is satisfactory; B - transition zone - dominance of blue-green more than 50%; in the lower part of the zone, absolute dominance is most likely (about 80-100% of the total biomass), where a sharp deterioration in water quality is possible and it is close to critical; С - critical zone - absolute dominance of sme-green algae (about 100%); in the upper part of the zone, accumulation of large biomass is possible, which degrades the quality of water; in the lower part of the zone, algae can age and die off, and the risk of biological contamination is increasing.

The graphic model was developed theoretically on the basis of known specific absorption coefficients and the most likely for functioning phytoplankton under normal conditions, a combination of the concentrations of the main pigments of blue-green, green and diatom algae. It was found that the ratio of optical density of the extract of pigments at wavelengths of 450, 480 nm (D450 / D480) in combination with the values at wavelengths of 480.664 nm (D480 / D664) can serve as a criterion for the dominance of blue-green algae (by biomass) in phytoplankton. And the contribution of blue-green biomass to phytoplankton can serve as an indicator of the degree of biological contamination of water: with an increase in the degree of dominance to 98-99%, the ecological state of the water body is not disturbed (biomass usually does not exceed 100 g / m3) a long time remains at about 100%, the water quality deteriorates as mass accumulation or algae surges and

decomposing them.

The calculated curves show the relationship of the optical density ratios of the amount of pigments in 90% acetone at wavelengths of 450, 480 nm (D450 / D480) and 480, 664 nm

(D480 / D664) depending on the carotenoid content. The values of D450 / D480 and D480 / D664 were calculated based on the known specific absorption ratios and the most probable ratios of pigment concentrations characteristic of different sections of the algae — blue-green, green, and diatoms. Only those that usually comprise up to 90% of the total concentration and are characterized by the largest value of the ratio D450 / D480 are included in the set of pigments. For diatoms, carotenoids – fucoxanthin: diadinoxanthin: / -carotene were selected in a ratio of 6: 3: 1 and the ratio of hrolophiles with / a was 0.3. For green

yS-carotene and chlorophyll b L / a = 0.3 were taken. For β blue-green, β-carotene and specific xanthophyll with astaxanthin ratios in the ratio 1: 1 are selected (there are no chlorophyll b and c in blue-green). These ratios were introduced into the calculation for individual types of algae and were taken as 100% in the calculations of mixed phytoplankton.

Top 1 shows character

CONNECTION INDICES D450 / D480 AND D480 / D664 FOR

the aforementioned mixture of diatom pigments, a curve of 2-2 1/2 pigments of blue-green plus 1/2 pigments of diatoms, a curve of 3- dl 3/5 of pigments of blue-green plus 1/5

pigments of green and 1/5 of diatoms, curve 4-for blue-green, curve 5 is conditional and designates a zone for young cultures of blue-green and condensed phytoplankton at the beginning of flowering. The listed curves divide zones with varying degrees of dominance of blue-green algae: samples with a blue-green content of less than 50% fall into the area between curves 1-2, usually between 50% between curves 2-3, and between 3-4 mostly about 80-99%, between 4-5 - samples of young cultures of green and phytoplankton, consisting of almost 100% of blue-green. Below curve 5 were samples for old and dying blue-green cultures. There were no natural samples from the zones of biological contamination.

Taking into account the distribution on the model of samples with different degrees of dominance and different levels of blue-green biomass, the following zones were identified: clean zone — blue-green dominance is usually not recorded here, less than 50% of the total biomass, which is characterized by small values; The condition of the water here is considered satisfactory. Transition zone In blue-green, they are usually dominated (more than 50%), the lower part of the zone is marked by a dotted line, where dominance reaches 80-98%; Critical biomass is possible, the trial is based on the fact that zooplankton samples containing mostly blue-green algae during the period of their predominance fall here. Perhaps a sharp deterioration in water quality. Critical zone C was selected based on the materials of blue-green cultures, samples of young cultures fall into the upper part of the zone, and old ones that are decaying fall into the lower part of the zone. It is likely that samples from a hazardous area of biological contamination with blue-green fall into this zone.

The method of monitoring the state of the water was implemented in May at 12 and in July at 11 stations. Water samples with a volume of 0.5 liters in May and 0.25 liters in July were taken from the upper half-meter layer in the lake and delivered to the laboratory. Phytoplankton from each sample was concentrated on membrane filters No. 6 with a diameter of 35 mm from a substrate of glass powder (100 mg) and chalk (100 mg) by filtration through a Plexiglas funnel using a surgical suction pump or a Komovsky pump. Each filter with plankton was placed in a penicillin vesicle, poured with 5 ml of 100% acetone; stopper and shake for about 3 minutes. The contents of the bubbles were transferred quantitatively into plastic centrifuge tubes, washing the sediment from the walls of the bubbles with 5 ml of 90% acetone. The precipitates were separated by centrifugation for 15 minutes at 8,000 rpm in a centrifuge. Over-sedimentary liquids — pigment extracts — were poured into glass tubes. Then the pigment extract was poured into a spectrophotometric cuvette 2 cm long, the optical density was measured on an SF-26 spectrophotometer at wavelengths of 450.480 and 664 nm. The ratio of optical densities was calculated at wavelengths of 450 and 480 nm (D450 / D480) and at wavelengths of 480 and 664 nm (Р4во / 0бб з) on the simplest calculator Electronics MK-42. Checked on a graphical model, in which zone the point falls

the intersections of the values of D450 / D480 and D-qeo / Deoi for each sample, established the degree of dominance, and estimated the condition of the water (see table).

For example, station 10 in May has a ratio of optical densities at wavelengths of 450 and 480 nm, equal to 1.63, at wavelengths of 480 and 664 nm - 0.95. We find the intersection point of these values on the model: looking for 0.95 on the abscissa axis, 1.63 on the ordinate axis.

It falls into zone A between curves 1 and 2. This zone belongs to the area in which blue-greens usually do not dominate and, accordingly, there is no biological pollution of blue-green, the state of water is classified as Pure.

Thus, we analyzed the data for the remaining samples - all points for the ma fall into this zone. All points of July fall into the zone between curves 3 and 4, in which

Blue-greens are dominated by up to 100%, but they do not reach the degree of biological contamination, the state of water is characterized by the category Transition with signs of deterioration in quality.

Formula of the invention

The method of determining the quality of water, including sampling water, concentrating plankton by filtration, extracting pigments with acetone, measuring

the optical density of the obtained extract at three wavelengths, one of which is 664 nm, characterized in that, in order to increase the express ™, the reliability and simplification of the method, the measurement at two

other wavelengths are carried out at 450 nm, 480 nm, the optical density ratio D450 / D480, D480 / D664 is determined, and water quality is judged based on a pre-built graphical model, where D / iso,

D480, 0) 664 are optical densities at 450, 480, 664 nm, respectively.

1 2 3

4 5 6

7 8

9 10 11 12

one...

2

3

four

five

6

7

eight

9

ten

eleven

12

R

/

Hell

Claims (1)

Claim A method for determining water quality, including sampling water, concentrating plankton by filtration, extracting pigments with acetone, measuring the optical density of the obtained extract at three wavelengths, one of which is 664 nm, characterized in that, in order to increase the express ™, reliability and simplification of the method, measurements at two other wavelengths are carried out at 450 nm, 480 nm, the optical density ratio D450 / D480, D480 / D664 is determined and the water quality is judged taking into account the previously constructed graphic model, where D450, 0480, Obb4 - pticheskie density at wavelengths of 450, 480, 664 nm, respectively. Station, No. Optical density, at, nm Attitude 450 ί 480 | 664 D450 / D ago L D48e / D £ 64 1 0.399 May 0.231 0.186 1.72 1.24 2 0.338 0.215 0.198 1,57 1,08 3 0.388 0.249 0.234 1,56 1.06 4 0.327 0.182 0.220 1.49 1.21 5 0.318 0.162 0.201 1,59 1.24 6 0.327 0.217 0.180 1.51 1.20 7 0.295 0.171 0.180 1.72 0.95 8 0,305 0.180 0.162 1,69 1,11 ' 9 0.313 0.195 0.156 '1,60 1.25 10 0.289 0.177 0.186 1,63 0.95 eleven 0.266 0.169 0.169 1,57 1,0 12 0.192 0.121 0,111 1,59 1.09 July 1- 0.234 0.413 0.427 0.365 0.374 0.360 0.488 0.412 100,461 110,401 120.324 cb m <r tn \ o r- ^ co σι 0.201 0.369 0.139 0.288 0.37.1 0,306 0.322 0.253 0.329 0.273 oh si 0.229 0.412 0.312 0.350 0.239 0.378 0.374 0.360 0.252 0.298 0.217 1,161,45 1,121,28 1.151.21 1.131.27 1.141.20 1.161.35 1,181.32 1,181,46 1,221,01 1.111.43 1.121.33 IOM PO & wog WHm / ρ ndu nauiiQUtugim hpheshio apnapishshd