RESULTS OF STUDIES OF ECOLOGICAL STATE OF WATERS AND SEA BOTTOM SOILS IN THE AMUR ESTUARY

Aleksandr V. Savelyev

JSC “Russian Ecological Alliance” (“REA-Consulting”), Vladivostok

Abstract: The article is devoted to the study of hydro-chemical characteristics and the content of pollutants in the waters of the Amur Estuary for the period from 1971 to 2008, as well as to the study of granulometric structure and quality of the bottom sediments in the estuary.

Keywords: Amur Estuary, hydrochemistry, pollutants, bottom sediments

  1. PURPOSE OF THE PAPER

In the last decade, a fairly active study of the Sakhalin Island’s shelf has been launched, particularly, within the Amur estuary of the Sea of Okhotsk. Above mentioned work is implemented for conducting geological exploration to assess the prospects for the production of hydrocarbons in this area. As a rule, while doing this the ecological expertise about possible influence on environment is required.  To do this, you need to know the background indicators of the environmental components. The purpose of this paper was to obtain a picture about background (undisturbed) state of the waters and soils of the Amur Estuary for the subsequent identification of the level of anthropogenic influence during geological exploration or any intensive economic activity.

2. DEGREE OF STUDY, SOURCE INFORMATION

Hydro-chemical parameters of the waters in the Amur estuary are presented on the basis of data obtained for individual years in the expeditions of Pacific Oceanographic Institute (POI) [1, 7, 10, 11, 12, 14, 15], in the expeditions of Research Institute of Water and Environmental Problems (IWEP) [16, 22, 23, 25], as well as on the basis of studies from earlier years [4, 21].

The typification of the bottom sediments in the Amur estuary and their granulometric composition are based on the results of observations in the expedition researches of POI [8, 9, 6]:

  • Scientific-research vessel “Academic A. Vinogradov” (1985);
  • Scientific-research vessel “Academic A. Nesmeyanov” (1987, 1990, 1992, 1993);
  • Scientific-research vessel “Academic M. Lavrentyev” (1988,1995);
  • Scientific-research vessel “Marine geophysicist” (1989)
  • Hydrographic vessels “BGK-495”, “BGK-492” (2005, 2006, 2007)

Additionally, information from literary sources was used to describe the lithological features of the Amur estuary [21].

The quality of bottom sediments is presented on the basis of the data given in the literature [2, 5, 12, 13, 17, 18].

3. HYDROCHEMICAL CHARACTERISTICS AND WATER QUALITY

The results of the study of the content of suspended matters in the waters of the Amur estuary are presented in Tables 1, 2, 3, 4. Research of suspended matters was performed at first by expeditions of Far Eastern labor camps (1936, 1940, in the system of Soviet Ministry of Internal Affairs), then by Primorsky Region Agriculture Institute (1971-1972), Far Eastern Regional Hydro-meteorological Research Institute – FERHRI, 1993. Later (1988-89; 2005-2008) the measurements were done during expedition researches of POI and Institute of Water and Ecological Problems (IWEP).

Table 1.Suspended matters’ concentrations in the waters of the Amur estuary according to the results of measurements in different years [21] In parenthesis there are shown average values.
Table 2. Suspended matters’ concentrations in the waters of the Amur estuary, summer of 1973 [4]
Table 3.Suspended matters’ concentrations (mg/dm3) in the waters of the Amur estuary according to the results of measurements in the expeditions of Pacific Oceanographic Institute [7, 10, 12]
Table 4.Suspended matters’ concentrations (mg/dm3) in the waters of the Amur estuary according to the results of measurements made by Institute of Water and Ecological Problems [22]

On average, in one year 23 million tons of suspended sediments with a grain size of 0.0001-0.4 mm are carried into the Amur Estuary with the waters of the Amur River. On the surface and up to the middle of the depth, particles with a diameter of less than 0.05 mm predominate, at the bottom – with a size of more than 0.1 mm. These particles, being in a suspended state, determine the turbidity of the waters in the Amur estuary. In the Estuary itself the water turbidity (suspended matters’ concentration) strongly depends on the water level of the Amur River, the speed of constant currents, tidal phenomena and storm conditions.

According to the available observations, the content of suspended matters (SM) in the waters of the Estuary may vary widely, depending on the area, from 3-114 mg/dm3 in the surface layer to 2-197 mg/dm3 in the bottom layer. The average concentration of SM in the water is 42 mg/dm3 and can increase significantly during a storm. A few observations during periods of severe storms show that the water turbidity in the estuary increases to 600-800 mg / dm3 [4]. Water turbidity reaches the maximum values in August-September, the minimum is observed in March. Tables 5-6 present the results of the study of individual hydro-chemical substances in the waters of the Amur estuary, based on the materials of hydro-chemical surveys of POI 2005-2007 and IWEP 2006, 2008.

Table5. Concentrations of hydro-chemical indicators in the waters of the Amur estuary according to the results of measurements in the expeditions of POI 2005-2007 [11, 14, 15]

Table6. Concentrations of hydro-chemical indicators and pollutants in the waters of the Amur Estuary according to the results of researches made by IWEP [22]

(End of introductory fragment)

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