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Changes in content of six trace elements in scales of the bream Abramis brama from the Mozhaisk Reservoir over a quarter century

Сведения об участнике
ФИО
Голубцов Александр Серафимович
ФИО (на английском языке)
GOLUBTSOV Alexander Serafimovich
Название организации
Институт проблем экологии и эволюции животных им. А.Н. Северцова РАН - ИПЭЭ РАН
Информация о докладе
Вид доклада
Устный доклад
Секция
Биоиндикация и химический анализ в экологическом мониторинге
Название доклада
Changes in content of six trace elements in scales of the bream Abramis brama from the Mozhaisk Reservoir over a quarter century
Соавторы доклада (ФИО, организация, город, страна)
Пельгунова Любовь Андреевна, Институт проблем экологии и эволюции животных им. А.Н. Северцова РАН - ИПЭЭ РАН, Москва, Россия; Салтыкова Елена Александровна, Институт проблем экологии и эволюции животных им. А.Н. Северцова РАН - ИПЭЭ РАН, Москва, Россия; Соколова Екатерина Леонидовна, Институт проблем экологии и эволюции животных им. А.Н. Северцова РАН - ИПЭЭ РАН, Москва, Россия; Скоморохов Максим Олегович, Институт проблем экологии и эволюции животных им. А.Н. Северцова РАН - ИПЭЭ РАН, Москва, Россия; Демидова Татьяна Борисовна, Институт проблем экологии и эволюции животных им. А.Н. Северцова РАН - ИПЭЭ РАН, Москва, Россия
Аннотация
Content of 11 trace elements in scales of the bream (Abramis brama) from the Mozhaisk Reservoir
collected in the second half of the 1980s were compared to the current values. Concentrations of
three elements studied changed severalfold during the past quarter
century: that of strontium has decreased, and those of barium and lead have increased. Short-term variations
of heavy metal contents have proved to be smaller than the observed longterm differences. We believe that these longterm differences adequately reflect the changes that have occurred in the Mozhaisk Reservoir.
Ключевые слова
trace elements, heavy metals, pollution, fresh waters, long-term dynamics, bream
Введение

In contrast to organic compounds, trace elements do not undergo transformation in aquatic food webs and leave biological cycle very slowly. Among trace elements, arsenic, cadmium, chromium, lead and mercury are regarded as the most dangerous toxicants [1]. Some trace elements (such as copper and zinc) are vitally important essential nutrients required for various biochemical and physiological functions. However, extra supply of these micro-nutrients can be toxic to organisms.

Bioconcentration of different trace elements in aquatic organisms can exceed environmental concentrations by orders of magnitude [2]. These elements enter fish organism through direct consumption of water and food as well as via nondietary routes such as uptake through absorbing epithelia [2,3]. Different organs and tissues of fish accumulate trace elements at different rates [4]. For understandable reasons, data about long-term dynamics of content of trace elements in aquatic organisms from the particular body of water are extremely scares in literature [5].

This study was aimed at the comparison of content of some trace elements in scales of the bream (Abramis brama) collected for age and growth rate investigations from the Mozhaisk Reservoir (Moscow District) in the late 1980s with the modern values in order to estimate the long-term ecotoxicological trends in this body of water.

Методы и материалы

Sample of the 1980s consists of 54 specimens (standard length, SL 166-403 mm) collected from November 1986 to September 1989. Modern material includes 45 specimens (SL 206-358 mm) collected in May-November 2015 and eight specimens (SL 260-301 mm) collected in May 2016. Scale samples (200-500 mg) were dissolved fuming nitric acid in the high-pressure microwave MARS (USA) at a maximum pressure of 800 psi at 240º C. The samples were analyzed as solutions using X-ray fluorescence spectroscopy with a spectrometer PicoTax TXRF (Bruker AXS, Germany) with a monochromatic radiation and optics for total reflection.

All manipulations were performed in disposable plastic utensils with extra-pure chemicals. Selenium was used as an internal standard (five mcg of selenium, GSO 7340-96, was injected into each sample). Since statistical distributions of most parameters studied deviated from normal, non-parametric methods were used.

Полученные результаты

For each fish sample data on the content of 11 trace elements – titanium (Ti), chromium (Cr), manganese (Mn), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), arsenic (As ), strontium (Sr), barium (Ba), and lead (Pb) – were simultaneously obtained. Contents of four of these elements (Ti, Co, Ni and As) was evaluated only for some specimens, because their content in other specimens did not exceed the threshold of spectrometer sensitivity (1 pg/kg). Data on these four elements are not considered in the present communication.

The remaining seven elements (Cr, Mn, Cu, Zn, Sr, Ba and Pb) were detected in the scales of all specimens studied. For most of these elements (excluding Mn) the content in the bream scales significantly changed over a quarter of century (Table 1). Content of two elements (Cr and Ba) decreased, while content of four elements (Cu, Zn, Sr, and Pb) increased.

Table 1. Content of seven trace elements (mg / kg of dry weight) in scales of the bream (Abramis brama) from the Mozhaisk Reservoir collected in 1986-1989 (n = 54) and 2015-2016 (n = 53).

Trace elements

1986-1989

2015-2016

p

median

min-max

median

min-max

Cr

20.45

3.07-189.30

12.70

1.66-65.70

< 0.0008

Mn

22.5

5.19-98.24

19.0

11.40-57.90

0.186

Cu

7.04

0.31-55.41

8.78

3.19-51.30

< 0.05

Zn

53.9

1.12-392.6

151.3

45.0-237.7

< 0.0001

Sr

150.0

99.5-276.6

37.8

32.1-69.7

< 0.0001

Ba

1.82

1.08-5.12

13.06

8.18-22.10

< 0.0001

Pb

0.24

0.06-1.95

2.94

0.74-7.02

< 0.0001

Notes: p - significance level of Mann-Whitney U-test; in 2015-2016 for Cu n = 51 and for Pb n = 52.

Surely, there are short-term fluctuations in the content of trace elements. For example, the subsamples of 1986-1987 (n = 23) and 1988-1989 (n = 31) differed in Zn content (medians 2.72 and 98.9 mg/kg of dry weight, Mann-Whitney U-test: p < 0.0005), no difference in content of other elements was found. Between seasonal subsamples of 2015 significant differences in the content of six elements were revealed (Table 2). Short- and long-term differences in content of Cr, Cu and Zn appeared to be quite comparable in magnitude. For three elements (Sr, Ba and Pb), the observed short-term fluctuations were substantially smaller than the long-term differences.

Table 2. Content of seven trace elements (mg / kg of dry weight) in scales of the bream (Abramis brama) from the Mozhaisk Reservoir collected in July 2015 (n = 20) and October-November 2015 (n = 18).

Trace elements

July

October-November

p

median

min-max

median

min-max

Cr

16.42

 6.31-41.50

7.20

2.13-65.70

< 0.02

Mn

19.46

11.90-54.03

17.16

11.98-37.80

0.409

Cu

6.23

3.92-9.13

19.84

11.7-47.10

< 0.0001

Zn

168.75

45.0-211.8

133.05

124.4-194.8

< 0.0001

Sr

38.49

       32.4-41.2

33.62

29.8-55.0

< 0.0001

Ba

13.95

11.8-18.1

11.73

10.00-18.2

< 0.005

Pb

3.02

2.31-4.89

2.26

0.74-7.02

< 0.228

Notes: p - significance level of Mann-Whitney U-test; for Cu in July n = 19 and October-November n = 17.

Заключение

It is reasonable to suggest that a decrease of Sr content, as well as an increase of Ba and Pb content reflect real changes occurring in the Mozhaisk Reservoir during a quarter of century. Increase in the level of Pb is of special ecotoxicological importance. Until 2010, the Mozhaisk Reservoir had the special status as a source for drinking water supply, but recently this status was withdrawn and the use of motor boats was allowed. Perhaps a sharp increase of lead concentration is caused by these circumstances. Strontium and barium penetrate into aquatic ecosystems mainly with terrestrial runoff and possibly their concentrations in fish tissues are determined by factors that act far beyond the borders of the Mozhaisk Reservoir.

In conclusion, we emphasize that the studies of fish scales and bone collections obtained earlier for the age and growth investigations and kept preserved in some ichthyological laboratories from previous decades, can be a effectively used in the studies long-term dynamics of trace elements in food webs of the targeted bodies of water.

Цитируемая литература
1. Tchounwou, P. B., Yedjou, C. G., Patlolla, A. K., Sutton, D. J. 2012. Heavy metal toxicity and the environment. EXS, 101:133–164. doi: 10.1007/978-3-7643-8340-4_6.
2. Алабастер Д., Ллойд Р. 1984. Критерии качества воды для пресноводных рыб. М.: Легк. и пищ. пром-сть, 344 с.
3. Brown D.A., Bay S.M., Hershelman G.P. 1990. Exposure of scorpionfish (Scorpaena guttata) to cadmium: effects of acute and chronic exposures on the cytosolic distribution of cadmium, copper and zinc. Aquatic Toxicology, 16 (4): 295–310.
4. Попов П.А., Андросова Н.В., Аношин Г.Н. 2002. Накопление и распоределение тяжелых и переходных металлов в рыбах Новосибирского водохранилища. // Вопросы ихтиологии. Т. 42. № 2. С. 264–270.
5. Johansen, P., Hansen, M.M., Asmund, G., Nielsen, P.B. 1991. Marine organisms as indicators of heavy metal pollution - Experience from 16 years of monitoring at a lead zinc mine in Greenland. Chemistry and Ecology, 5: 35–55.
Благодарности
This study was supported by the Russian Foundation for Basic Research (project № 15-29-02772).
Название, авторы, резюме (на английском языке)

Changes in content of six trace elements in scales of the bream Abramis brama from the Mozhaisk Reservoir over a quarter century

 

А.S. Golubtsov, L.А. Pelgunova, Е.А. Saltykova, Е.L. Sokolova,

М.О. Skomorokhov, Т.B. Demidova

 

Content of 11 trace elements in scales of the bream (Abramis brama) from the Mozhaisk Reservoir
collected in the second half of the 1980s were compared to the current values. Concentrations of
three elements studied changed severalfold during the past quarter
century: that of strontium has decreased, and those of barium and lead have increased. Short-term variations
of heavy metal contents have proved to be smaller than the observed longterm differences. We believe that these longterm differences adequately reflect the changes that have occurred in the Mozhaisk Reservoir.