Pollution load on the Gulf of Finland in 1982-1984

22

YMPÄRISTÖHALLITUS

56°

HEIKKI PITKÄNEN, JUHANI PUOLANNE, MATTI PIETARILA, AIN LÄÄNE, ENN LOIGU, PEEP KUSLAP & TIIU RAIA

POLLOUTION LOAD ON THE GULF OF FINLAND IN 1982—1924

A reportof studies under the Finnish-Soviet Working Group on the Protection of the Gulf of Finland

O.

VESI- JA

22

HEIKKI PITKÄNEN, JUHANI PUOLANNE. MATTI PIETARILA, AIN LÄÄNE, ENN LOIGU, PEEP KUSLAP & TIIU RAIA

POLLUTION LOAD ON THE GULF OF FINLAND IN 1982—1984

A report of studies under the Finnish-Sovaet Workrng Group on the Protection of the Gulf of Finland

VESI- JA YMPÄRISTÖHALLITUS

The authors are responsible for the text, and it should not be cited as the official opinion of the National Board of Waters and the Environment.

Tekijät ovat vastuussa julkaisun sisällöstä, eikä siihen voida vedota vesi- ja ympäristöhallituksen viraliisena kannanortona.

VESI- JA YMPÄRISTÖHALLI N NON JULKAISUJA koskevat tilaukset:

Valtion painatuskeskus, PL 516, 00101 Helsinki puh. (90) 566 01 /julkaisutilaukset

ISBN 951-47-1807-0 ISSN 0783-327X

VAPK Kampin VALTIMO HELSINKI 1988

Vesi- ja ymphriatöhallitus

Tekij(t) ftoimielimemtä: nimi, puheenjohtaja, sihteeri)

Heikki Pitkänen, Juhani Puolanne, Matti Pietarila. Ain Läne. Enn Loigu. Peep Kuslap ja Tiiu Raja

Julkaisun nimi (myös ruotsinkielinen) Suomenlahden kuormitus vuosina 1982-1984

Julkaisun laji Toimekeiantaja Toisielimen asettamispvm

Tutkimueraportti

Julkaisun osat

Tiivistelmä

Raportissa tarkastellaan Suomenlahteen Suomesta ja Neuvostoliitosta pistemäisistä lähteistä sekä jokien ja ilman kautta joutuvan kuorman suuruutta Työ on tehty suomalais-neuvostoliittolaisen Suomenlahti- työryhmän asiantuntijayhteietyönä

1

— Suomenlahteen joutui vuosina 1982-1984 keskimäärin

6 800 t a foeforia, 130 000 t a typpeä ja 410 000 t a orgaanista ainetta 800 -arvona. Foefori kuorma kasvoi 8 % ja 800-kuorma 18 vuosiin 1980-1981 verrattuna. Nousu johtui lähinnä virtaamien kasvusta Neuvostoliiton joissa erityisesti Nevassa Typen kuormassa ei 1980-luvulla tapahtunut huomattavia muutoksia ^- Esitetyt ravinteiden kuormitusluvut ovat luultavasti aliarvioita Tämä johtuu pääasiassa metodologisista vaikeuksista Suomenlahden ilmeisesti merkittävimmän yksittäisen jätevesikuormittajan, Leningradin, aiheuttaman kuormitukeen arvioinnissa. ^— Toteutetulata vesien—

muojalutoimenpiteistä huolimatta Suomenlahteen joutuva kokonaiskuorma kasvoi vuosina 1975-1984.

Tämä Johtui jokien samaan aikaan kaevaneiata virtaamista ja lisääntyneiatä huuhtoutumista —

Tulevaisuudessa Suomenlahden kuormitustutkimusta tulee kohdistaa erityisesti haitallisiin

aineimiin, ilmaperäiseen kuormitukseen ja jokien tuomien ainemäärien alkuperään ja käyttäytymiseen.

Suoraan jokisuistoihin joutuvan kuorman suuruutta tulee mahdollisuuksien mukaan seurata erillään Jokien tuomasta kuormasta.

Asiasanat (avainsanat)

Kuormitus, ravinteet, orgaaninen aine. Suomenlahti. Itämeri, seuranta.

Muut tiedot

Sarjan nimi ja numero ISEN ISSN

Vesi— Ja ymprimtoha11innon Julkaisuja nro 22 951 47—1807—0 0783—327X

Kokonaissivumäärä Kieli Hinta Luottamuksellisuus

29 Englanti Julkinen

Jakaja Kustantaja

Valtion painatuskeskus Vesi- ja ympäristöhallitus

4

DOCUMENTATION PAGE

Published by

The National Board of Uaters and the Environment. Finland

Date of publication

Authorfs)

Heikki Pitkanen. Juhani puolanne. Matti Pietarila. Aine Lähne. Enn Loigu. Peep Kuslap and Tiiu Raia

Title of publication

Follution load on the Gulf of Finland in 1982-1984

Type of publicatien Commissioned by Research report

Parts of publication

Abstract

The report presenta estlmated figures and discussion on the pollutien load dfscharged Into the Gulf of Finland from direct point sources and via rivers and the atmosphere. The uork has been compiled as a co-operation of scientists and experts from Finland and the USSR under the Finnish-Soviet Working Group on the Frotection of the Gulf of Finland.1- During 1982-1984 the Gulf of Finland received on en average 6 800 t a of phosphorus. 130 000 t a of nitrogen and 410 000 t a of organic matter as BOD. The figures for BOD and phosphorus were 8 and 18 higher than during 1980-1981. respeotively.

The inorease was largely due to increased water flows in the Soviet rivers. especially in the River Hava. Discharges of nitrogen did not increase markedly during the 1980s. ^— The present values

probably underestlsate the actual nutrient loading. mostly due to methodological difficulties in assessing discharges from Leningrad which evidently is the most significant individual anthropogenic source of loading by the Gulf of Finland. ^— In spite of water protection measures and improved waste water

treatment in both countries. the total load to the Gulf of Finland increased during the period 1975—1984. due to increased uater flows of rivere and increased leaching from land. ^- In the future it is important to pay attention to discharges of harsful ^g•O stances ^{and the role of} atmospheric loading. as uell as to the origins and behaviour of riverine disharges. Direct loading discharged into the estuaries should he sonitored separately from the riverine load whenever this is possible.

Keywords

Pollution load. nutrients. organic matter. Gulf of Finland, Baltic Sea. monitoring.

Other inforsation

Series (key title and no.)

Publications of the Water and Environment Adminlstration no. 22

Pages Language

29 English

Distributed by

Government Printing Centre

ISBN ISSN

951—47—1807—0 0763—327X

Price Confidentiality

Pubije

Publisher

The National Board of Waters and the Environment, Finland

PesloMe

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CONTENTS

Page

1 INTRODUCTION

9 2 THE GULF OF FINLAND AND ITS CATCHMENT ÄREÄ 10

3 RIVER DISCHÄRGES 13

4 DIRECT WÄSTE WÄTER LOAD 14

5 DEPOSITION FROM THE ÄTMOS?HERE 19

6 TOTAL DISCHARGES

20 7 DISCUSSION

23 8 FUTURE PERSPECTIVES IN DISCHARGE ÄSSESSMENTS 25 REFERENCES

27

INTRODUCTION

In 1978 Finland and the USSR exchanged, unaer the Finnish Soviet Working Group on the Proteotion of the Gulf of Finland, national information on poliution load discharges into the Gulf of Finland from the years 1975-1976. This information was compiled as the first Ioading report (Finnish-Soviet Working Group 1979). Since then additional reports have been published for the years 1977-1979 (Fin nisli-Soviet Working Group 1981) and for the years 1980- 1981 (Finnish-Soviet Working Group 1984).

This report is the fourth in turn and it has been compiled of the pollution load studies of the Finnish-Soviet Working Group on the Protection of the Gulf of Finland. The Group is one of the three working groups of the Joint Finnisli-Soviet Cornmission on Environmental Protection.

Information for the work has been collected in Finland in the National Board of Waters and the Environment and the Meteorological Institute, and in the USSR in the Äcademician Fedorov Institute of Äpplied Geophysics, Baltic Branch, Estonian SSR and Estonian Water Management Ägency by the Council of Ministries of the Estonian SSR.

The report has been produced in co-operation by experts from both countries, between and during the regular mcc tings held each year. Ä symposium covering the topic and providing an occasion to enhance the exchange of information was arranged in September 1987 in Tallinn.

Responsible for providing the material and for compiling the work are Juhani Puolanne, Heikki Pitkänen and Matti Pietarila from Finland and Äin Lääne, Enn Loigu, Peep Kuslap and Tiiu Raia from the USSR. The report has been edited by Heikki Pitkänen and Juhani Puolanne.

10

2 THE GULF OF FINLAND AND ITS CÄTCHMENT AREÄ

Waters from an area of 421 000 km2 are drained into the Gulf of Finland (Table 1, Fig. 1). The coasts of the Gulf are densely populated and industrialized in both countries around the sea area. Äs the catchment area is also rather intensively cultivated, it is evident that the loading entering the Gulf has strongly increased from its natural level. Äs a resuit of this, effects on the state of the ecosystem are probable both in the coastal and open waters of the Gulf (Baltic Marine Environment Protection Commission 1987).

The Gulf of Finland has a sill-free connection to the Baltic Proper. The sea area is shallow, the average depth being only 38 m. The Gulf, especially the eastern part of it, is affected by a strong freshwater infiow from rivers (Table 2). Surface salinity at the entrance of the Gulf is 6-7 °/ decreasing towards the eastern end with increasing proportion of river water, The average direction of surface currents in the sea area is counter clockwise due to the Coriolis effect, Local currents, especially near the coast, een to a large extent be epiained by geomorphological and rneteorological factors.

Loading of nutrients and organic matter primariiy afiect productivity and oxygen conditions of coastal waters As a result of density stratification and the input of organic matter from the surface layer, oxygen conditions in waters near the bottom are, however, often poor in the deep water of the Gulf. Great amounts of nutrients, especially phosphate, are enriched in this water layer.

Älthough being excluded frorn the roduction cycie of the surface layer, these nutrients een also cause eutrcphicati on under proper weather conditions via upweiling in near coastal waters.

basin of the Gulf of Finland.

Figure 1. The arainage

12

Table 1. Morphometrical and hydrological (Falkenmark and Mikuiski 1974).

data on the Gulf of Finland

Area 29 600 km2

Max depth 123 m

Volume 1 100 km3

Drainage area 421 000 km2

Inflow of river water 117.9 km3/a (1951—60) 108.8 km3/a (1961—70)

Table 2. Data on river basins draining have been extrapolated to correspond to

x) The investigation periods are:

to the Gulf of Finland. The Finnish values the whole basias.

River Drainage Examined Mean water flow Annual mean flow;

area: km2 part of duriny investi- km3/a

drainage gation period: 1982 1983 1964 3 x)

area; km /a

Finland

Vlrojoki 360 96 0.11 0.12 0.13 0.17

Kymijoki 37 200 98 9.57 11.9 10.1 11.9

Koskenkylänjoki 890 51 0.25 0.28 0.24 0.43

Porvoonjoki 1 270 90 0.37 0.44 0.36 0.62

Hustijoki 785 83 0.23 0.24 0.16 0.36

Vantaanjoki 1 690 100 0.52 0.54 0.35 0.72

Karjaanjoki 2 050 96 0.54 0.59 0.54 0.80

USSR

Neva 281 000 100 79.2 97.5 82.3 85.1

Luga 13 200 100 2.81 3.88 3.44 3.35

Narva 56 200 99 10.9 14.6 13.2 10.6

Jägala 1 580 78 0.42 0.42 0.39 0.46

Neva 1859 ^— 1982 Virojoki 1966 — 1980

Luga 1944 ^— 1982 Kymijoki 1961 ^- 1980

Narva 1956 ^- 1982 Koskenkylänjoki 1961 ^- 1980 Jägala 1942 ^- 1982 Porvoonjoki 1963 ^— 1980

Nustijoki 1966 ^- 1980

Vantaanjoki 1961 ^- 1980 Karjaanjoki 1961 - 1980

Mean values of the period 1982-1934 are presented for organic matter (30D7, C0D), nitrogen (tot.N, N03-N), phosphorus (tot.P, P04-P) and suspended solids.

The river Kymijoki in Finland was sampled 44-59 times during 1982-1984, depending on variable (Table 3), The Rivers Koskenkylänj oki, Porvoonj oki, Vantaa and Karj aanj oki were sampled about 12 times a year and the Rivers Virojoki and Mustijoki 4-6 times a year.

In the USSR the River Neva was sampled 36-101 times and the River Luga 12-34 times during 1982-1984, depending on the river and variable (Table 3). In other Soviet rivers, samples were collected 4-6 times a year, during the distinctive hydrological periods. In addition, some small rivers with a total drainage area of 4916 km2 were investigated. Water flow was measured daily in both oountries.

Material transport calculations were based on mean monthly concentrations and mean monthly flows in Finland. In case of missing monthly values, they were replaced by the corresponding mean value for the whole year. In the USSR calculations were based on yearly mean values.

Äccording to the calculations, during 1982-1984 the Gulf of Finland received from rivers, on an average,

5 800 t a of phosphorus, 94 000 t a of nitrogen and 2 800 000 t a of organic matter as COD or 350 000

t a—1 as BOD7 (Table 4, Figs. 2a, b).

When assessing river discharges it should be taken into account that the pollution loads from e.g. Leningrad and Narva, situated immediately upstream of the sampling stations, are included in the river discharges. In the lower course of the River Kymijoki loads from several pulp and paper mills are included in the river äischarges as well.

14

Table 3. The amounts of chemical analyses from sampies taken during 1982-1984

River Number of analyses during 1982-1984

30D7 COD N P Suspended

solids

Finland:

Virojoki (4) 14 15 15 15

Kymijoki 44 58 47 47 59

Koskenkylänjoki 18 37 37 40 39

Porvoonjoki 32 34 34 34 34

Mustijoki (11) 12 12 12 12

Vantaa 33 35 35 35 33

Karjaanjoki 33 34 33 34 33

USSR:

Neva 101 45 90 36 46

Luga 34 30 12 12 18

other rivers 12-18 12-18 12-18 12-18 12-18

4 DIRECT WASTE WATER LOÄD

The amounts of treated or untreated municipal and indust rial waste waters, and the respective loads of BOD7 and nutrients, discharged directly to the Gulf of Finland, are given in Table 5.

The total volume of direct sewage and waste water dischar ges to the Gulf from Finland was close to 600 000 rn3/d, of which 34 % were industrial waste waters. Most of the sewage was biological-chemically treated, In 1983 only 0.6 % of the municipal sewage was treated in individual septic tanks and without centralized treatment. In indust ry, water pollution control was impiemented by botli process technical measures and external waste water treatment.

From the Finnish side, sewage of sorne 970 000 people living mainly in Helsinki and the neighbouring towns were dischar ged through sewers into the Gulf of Finland in 1982-84.

Ädditionally, the treated sewage of sorne 400 000 inliabi tants living further upstream contributes indirectiy to the river discliarges.

Table 4. River dlacharges of organic matter. nutriente and suspended sollde to the Gulf of Finland in 1982-1984 (t/a)

River BOD7 COD Tot.N N03-N Tot.P P04-P Suspended

solids4

Finland

Virojoki1) _.. 2 200 140 49 9.1 3.7 1 800

Kymijoki 30 000 110 000 6 900 2 600 290 65 55 000

Koskenkylänjokl 530 3 100 490 260 33 15 9 300

Porvoonjoki 1 600 5 300 1 500 900 77 42 21 000

Mustijoki _.. 4 200 430 .. 29 . . 9 500

Vantaa 1 900 7 300 1 500 850 85 45 27 000

Xarjaanjoki 650 5 000 580 260 23 8.2 3 300

The reet of the basin 5 300 24 000 4 000 2 600 220 120 62 000

Total 40 000 160 000 16 000 7 500 760 300 190 000

USS R

Neva2) 248 000 2 000 000 49 000 21 000 3 200 1 500 800 000

Luga 3) 8 900 109 000 7 000 4 800 280 120 17 700

Narva 35 000 306 000 .. 9 200 670 290 91 700

Jägala 1 000 17 500 930 600 30 10 3 000

Investigated small

rivera (summarized) 4 800 52 600 4 400 3 000 200 90 21 000

The rest of the basin 17 000 184 000 16 700 10 500 650 310 73 000

Total 315 000 2 670 000 78 000 49 000 5 000 2 300 1 010 000

The whole drainage 350 000 2 800 000 94 000 57 000 5 800 2 600 basin of the Gulf of

Finland

1) including the discharges from several pulp and paper eilis

2) including the discharges from LenIngrad. The nutrfent values probebly underestimate the actual loading due to methodological difficulties iii manitoring the River Neva below the City of Leningrad.

3) includlng the discharges from Narva

4) filter pore size 1 )zm in Finland and 0.45 in the USSR

16

700 m3 s 500

“ 600

300 200 100 0

1200 tQ•1

€

600

.- 400

- 200

0

24 clO3t a w

2 ¹⁶

c 12

8 6 0

Figure 2a. River discharges of organic matter (COD) and nutrients from Finland during 1970-1984.

The Rivec Kymijoki Other tivecs

200000

150000

100000

50000

0

1970—72

The RiverNeva The River Narva

WE[II

L1

75-76 77-79 80—81 82—84

Figure 2b. River discharges of organic matter (3007) and nutrients from the USSR during lg7o-1g84.

ta

t a’

300000

250000

1%

18

Table 5. Direct uaste water load of organic matter and nutriente to the Gulf of Finland in 1982—1984.

Source Waste water 2007 Tot.N Tot.P

volume m3/d t/a t/a t/a

Finland

Hunicipal discharges:

Helsinki area Kotka—Hamina area Porvoo area Other comsunities

Industrial discharges:

Pulp and paper industry in the Kotka-Hamina area Refinery and petroohemiaal industry in the Porvoo area Other industries

Induatrial discharges:

Pulp and paper industry in Tallinn

in Viborg

Fertilizer industry in Maardu

Oil-shale induetry in Xoht1a-Jrve1)

Total load te the Gulf of Finland

3 270 3 430

270 140

150 130

470 230

103 15 5 20 329 100

27 000 14 100 24 400

Total load from Finland

UssR

Municipal discharges:

TalI inn Viborg

394 600 4 160 3 930 143

153 800 14 800 200 34

16 300 310 130 4

31 100 960 28 3

201 200 16 070 358 41

596 000 20 200 4 290 184

325 000 19 700 3 800 350

18 000 800 170 22

343 000 20 500 3 970 372

38 000 16 000 .

39000 3700 1650

28 000 280 100 130

35 500 390 580 16

Totel load from the USSR

140 500 20 370 (2 330+) (146+)

483 500 40 800 (6 300+) (518÷)

1 080 000 61 100 (10 600+) (702+)

including the municipality

On the Soviet side of the Gulf, the corresponding total sewage and waste water volume was close to 500 000 m3/d, of which 29 % were industrial waste waters. Äbout 65 % of the total amount were mechanical-chemically treated and 20 % biologically treated.

Of the municipal waste waters from the Soviet side only the sewage of Tallinn (about 450 000 inhabitants) and Viborg (80 000 inhabitants) were discharged directly to the sea. Äs some 6 million people live near the coast, mainly in Leningrad, the sewage load is mostly included in the river discharges. Since 1985 the treatment plant on Island Belyi (1.5 million m3/d) has been in operation.

Ät present three biological treatment plants are under construction in Leningrad ^- additional treatment plant of 0,25 million m3/d on Island Belyi, Northern treatment plant of 1.5 million m3/d and South-Western treatment plant of 0.5 million m3/d (Velner 1987).

In Finland, most of the smaller industrial plants for food, metal, textile and leather processing were connected to municipal sewage networks. The bigger industrial plants had, in general, their own separate sewer systems.

The most significant industrial poiluters on the Finnish coast were the puip and paper industry in the Kotka-Hamina area and the oil refinery and the petrochemical industry near the town of Porvoo. In addition, the increasing nutrient load from fish farming deserves to be mentioned

(see Pietarila and Ruonala 1988).

In the USSR almost ali industrial plants were connected to municipai sewer systems. The puip and paper industry in Tallinn and Viborg and the fertilizer industry in Maardu had their separate sewer systems.

5 DEPOSITION FROM THE ÄTMOSPHERE

Since 1979 Finland has had one sea station in operation on the island of Haapasaari about 30 km off the town of Kotka for the measurement of airborne deposition. Based

20

on the measured data, the average deposition on the Gulf of Finland was 22 000 tons of total nitrogen and 300 tons of total phosphorus per year in the period 1982- 1984 (Data of the Finnish Meteorological Institute).

The estimates, especially those of nitrogen, are close to those presented for the period 1979-1982 in the earlier report (N 24 000 t a and P : 400 t a). However, the representativeness of these values is very doubtful, on account of only one measuring station for the whole area

According to the values given by the Finnish Meteorological Institute atmospheric loadings of lead and cadmium into the Gulf of Finland were 300 t a and 6.2 t a, respecti vely.

6 TOTÄL DISCHARGES

The total input to the Gulf of Finland during 1982-84 was estimated to about 6 800 t a of phosphorus,

130 000 t a of nitrogen and 410 000 t a of organic matter as BOD7 (Fig. 3). The values of phosphorus were

8 % higher and the values of organic matter 18 % higher then in the previous report, covering the years 1980- 1981. No great changes took plaoe in the total input of nitrogen.

Rivers were the mcm source of both organic matter and nutrients, comprising 85 and 72 * of the total load of phosphorus and nitrogen, respectively, and 85 * of the total load of organic matter, Ät least one half of the riverine nutrients was in inorganic form, thus being directly available for primary production during the productive season, The proportion of inorganic nitrogen is, however, clearly greater, because a part of the nitrogen is discharged into the coastal waters in the form of ammonium, discharges of which could not be included in this report.

It should be emphasized that in spite of the water

21

OlD7 Tot N Tot P

600 x103ta1

J,j 140 7

1

300 ¹

250 100

f

200 80 6

150 60 3

100 40 2

50 20 1

0 0 0

1980 1982 1980 1982 1980 1982

—81 —86 -81 —86 —81 —84

1 1

Figure 3. Total discharge of organic matter (30D7) and nutrients to the Gulf of Finland in 1980-1981 and 1982-

1984.

22

1200

t .4

1100

1000 —

J : ^L••,

700 600

12000

t 0•1

11000

r ^-

•———J

10000

f

cci)

9000

1

z

8000 7000

90000

t o•1

80000

:::

50000

1975 — 76 1977 ^— 79 1980 — 81 1982 ^— 8L

Figure 4. The total direct pollution load on the Gulf of Finland during 1975-1984. Broken lines refer to some missing data.

(Fig. 4), a large amount of the riverine load stiil originates from waste waters, especially in the River Kymijoki in Finland and the River Neva in the USSR. In the three most loaded Finnish rivers (Kymijoki, Vantaa, Porvoonjoki) the proportion of waste water phosphorus is 20-30 % ^{of the} total annual phosphorus transport, and 30-60 % of the summer period transport (Pitkanen 1988)

Ätmosphere seems to be an outstanding source of pollution, especially as regards heavy metais. Äccording to the results presented, inputs of lead and cadmium via atmosphe—

re into the Gulf of Finland are, for example, one order of magnitude higher than inputs via the Finnish rivers.

The atmospheric load of nitrogen is also large, being about 20 % of the total input into the Gulf It seems very likely that atmospheric loading of nitrogen has increased during the recent decades (Järvinen 1986).

7 DISCUSSION

Within the Finnish-Soviet Working Group on the Protection of the Gulf of Finland information on discliarges from land has been exchanged since the beginning of 1970’s Äfter that, analytical methods have been improved and the monitoring of discharges has developed. Therefore the results from the early 1970’s and from the recent years are not directly comparable.

The present figures probably underestimate the actual nutrient loading, mostly due to methodological difficul ties in assessing discharges from Leningrad which evidently is the most significant individual anthropogenic source of loading by the Gulf of Finland (cf. Skakalsky 1988).

In Finland the calculation method of river discharges has changed. Results of the earlier calculations, based on yearly mean values, and the present system, based on rnonthly mean values, are not directly comparable with each other, and therefore the whole Finnish data has

24

been rehandled (Figs. 2a and 3).

The variations in river diseharges are mainly dependent on hydrological factors in different years, as leaching from land is largely dependent on runoff (Figs. 2a, b).

Howewer, disciarges are naturally also dependent on poin-C loading into the rivers. In 1975-1976 the runoff and stream flow were extremely low, whereas in 1977-1979 they were close to the long-term average. In the 1980s the values have been extremely high. This means that despite of decreased waste water loading of pliosphorus and organic matter the calculated total discharges of these substances have increased during 1975-1984.

The effects of various factors with a bearing on material transport in rivers are rather difficult to separate from each other, According to the recent studies it seems that in addition to changes in the point-source waste water loading of rivers, non-point loading from agriculture also affects markedly the nutrient transport of rivers

(Maastik and Mets 1988, Rekolainen and Kauppi 1988).

During 1975-1981 the average total discharges of organic matter (30D7

)

Soviet side. During the 1980s, however, an increase took place, which obviously was largely due to the in creased water flows, Due to water pollution control measures, the proportion of waste water load included in the river discharges has decreased. Considerable reduc tions have been reported, for instance, in the waste water loads into the Jägala and Neva Rivers.

The 30D7-load from pulp and paper industry into the Kymi joki in Finland decreased considerably in the 1970’s (nearly 50 % during 1974-1978), due to water pollution control measures and changes in the volume and quality of production. Ä slight decrease has also taken place during the early 1980s, On the other hand direct phospho rus discharges from pulp and paper industry liave somewhat increased, Industrial nitrogen discharges liave clearly

in oil refinery and petrochemical industries.

The treatment of municipal sewage lias become more effective in the population centres both on the coast and along the rxvers £lowing into the Gulf of Finland from the Finnish territory. Thus, the transport of phosphorus and organic matter have on ari average decreased during the 1970s and early 1980s in the Rivers Kymijoki, Vantaa and Porvoonjoki, although trends in water flows have been increasing.

During 1975-1984, and more specifically in the early 1980’s, some positive development in the drect waste water load has taken place, although an increased number of inhabitants have been connected to sewer networks and the industrial activities in both countries have increased (Fig. 4). Compared witli the 2nd and 3rd reports of the Working Group on the Protection of the Gulf of Finland, the total direct 30D7 discharges have been reduced by 11 % and phosphorus discharges by 30 %. This reduction is mainly due to the more effective municipal sewage treatment (especially 80D7 discharges from the USSR and phosphorus discharges from Finland) and some changes in industrial production and the use of water in industries.

However, the increase of the total direot loading of nitrogen is inevitable, because nitrogen rEmoval is not really practiced.

8 FUTURE PERSPECTIVES IN

DISCHÄRGE ASSESSMENTS

So far, mainly traditional discharge parametres have been used to describe the pollution load entering the Gulf of Finland. There is, however, an increasing need to evaluate and monitor the discharges of harmful substan ces. Moreover, the origins of loads carried by rivers need to be decsribed more exactly.

To increase the availability of the assessment of pollution

26

discharges to the Gulf of Finland, more emphasis should be given in the research activities to at least the follo wing items:

— Discharges of harmful substances. Ät present, analy tical methods for most of the harmful substances are not sufficient for routine monitoring. Monitoring of riverine heavy metais began in Finland in 1982 but the results are stiil tentative, giving only the magnitude of the loading. Industrial heavy metal disoharges are monitored in both countries, but there is lack of infor mation on munioipal discharges in Finland, There is also en urgent need for knowledge about the discharges of various halogenated hydrocarbons and petroleum hydro carbons in river and waste waters as well as in the atmospheric deposition.

— The effect of sampling frequency on the river transport and the annual variation in the transport. According to the recent studies it seems favourable to f ix the time of sampling according to hydrological conditions in a river (e.g. Jumppanen and Kolehmainen 1986 , Loigu et al. 1988). Thus high-flow periods should be much more frequently sampled than low-flow periods.

The role of atmospheric inputs. The loading via atmos phere is important as regards nutrients, but it is of primary importance as regards heavy metals and other harmful and toxic substances. For example, according to the rough estimates given in this report, the deposi tion values of Pb and Cd are about 20-30 times greater than the corresponding riverine discharges from Finland.

- Urban runoff, The magnitude and importance is largely unknown, but it is probably very important for many pollution load parameters.

- The net loading of the open sea, Only estimates of the gross loading of the sea areas are known. Estuarine

from land both guantitatively and gualitatively.

- The origins of the riverine loading. Relatively little is known about the primary sources of riverine substan ces. Especially the role of non-point source loading is largely unknown Recently it has been estimated that 60-70 % of the Finnish riverine nutrient load of the Gulf of Finland is of agricultural origin.

In cases where there are substantial polluters near the river mouths, river discharges should be monitored upstream of point-sources, and loading discharged down stream should lie included in the direct waste water load to the sea.

9 REFERENCES

Baltic Marine Environment Protection Commission, Helsinki Commission 1987. First periodic assessment of the state of the marine environment of the Baltic Sea area, 1980-1985; background document. Baltic Sea Environrnent Proceedings no. 17 5, 351 p.

Falkenmark, M. & Mikuiski, Z. 1974. Hydrology of the Baltio Sea General background to the interna tional project. Water Balance of the Baltic Sea - a Regional Cooperation Project of the Baltic Countries. Project Document no. 1, 51 p.

Finnish-Soviet Working Group on the Protection of the Gulf of Finland 1979, 1981, 1984. Discharges from land and ar Mimeographed reports

Jumppanen, K. & Kolehmainen, 0. 1986. Nutrient discharge by the River Äurajoki to the Ärchipelago Sea Publications of the Water Research Institute no. 68, p. 62-66.

28

Järvinen, 0. 1986. Laskeuman laatu Suomessa 1971-1982 [The quality of wet and dry deposition in Finland in 1971-1982] ^. Vesihallituksen monistesarja no, 424, 142 p.

Cm

Loigu, E., Kuslap, P. & Leisk, U. 1988. Methodological aspects for evaluation of pollutants discharged by rivers. 7th Soviet-Finnish Symposium on the Gulf of Finland, Tallinn, USSR, 10-14 August 1987. Vesi- ja ympäristöhallinnon julkaisuja.

(in print).

Maastik, Ä. & Mets, L. 1988. Assessment of the agricultural pollution load of surface waters. 7th Soviet- Finnish Symposium on the Gulf of Finland, Tallinn, USSR, 10-14 August 1987. Vesi- ja ympäristöhal linnon julkaisuja. (in print).

Pietarila, M. & Ruonala, S. 1988. Industrial waste water loading from Finland into the Gulf of Finland. 7th Soviet-Swedish Symposium on the Gulf of Finland, Tallinn, USSR, 10-14 August 1987. Vesi- ja ympäristöhallinnon julkaisuja.

Cm

Pitkänen, H. 1988. Loading transported to the Gulf of Finland by the Finnish rivers. 7th Soviet-Finnish Symposium on the Gulf of Finland, Tallinn, USSR, 10-14 August 1987. Vesi- ja ympäristöhallinnon julkaisuja. (in print).

Rekolainen, S. & Kauppi, L. 1988. The evaluation of diffuse load and its signifmcance of the total nutrient transport by rivers to the Gulf of Finland from Finland, 7th Soviet-Finnish Symposium on the Gulf of Finland, Tallinn, USSR, 10-14 August 1987. Vesi- ja ympäristöhallinnon jul kaisuja. (in print).

loading in the Gulf of Finland from the Neva basin. In: Baltic Marine EnvironmentProtection Commission. The Baltic Se& Pollution Load Monitoring Symposium, Tallinn, USSR, 5-9 Äpril 1988. Reprint copy of the statements, p. 170-182.

Veiner, H. 1987. Leningradin vesiensuojelu ja sen vaikutus Suomenlahteen [Water pollution control of Leningrad and its effect on the Gulf of

Finland]. Vesitalous 28:1-3. (in Finnish).

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