VESI- JA YMPÄRISTÖHALLINNON JULKAISUJA · vesi- ja ympÄristÖhallinnon julkaisuja 22 heikki pitkÄnen, juhani puolanne, matti pietarila, ain lÄÄne, enn loigu, peep kuslap & tiiu

VESI- JA YMPÄRISTÖHALLINNON JULKAISUJA

22

HEIKKI PITKÄNEN, JUHANI PUOLANNE, MATTi PIETARILA,

AIN LÄÄNE, ENN LOIGU, PEEP KUSLAP & TIIU RAtA

POLLUTION LOAD ON THE GULF OF FINLANDIN 1982—1984

A report of studies under the Finnish-Soviet Working Groupon 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 Boardof Waters and the Environment.

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

VESI- JA YMPÄRISTOHALLINNON JULKAISUJA koskevat tilaukset:Valtion painatuskeskus, PL 516, 00101 Helsinkipuh. (90) 566 01/julkaisutilaukset

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

VAPK Kampin VALTIMO HELSINKI 1988

KUVA 1 LULEHT :.

Julkaisija Julkaisun päivämäräVesi- ja ympäristöhallitus

Tekija(t) (toimielimestä: nimi, puheenjohtaja, sihteeri)

Heikki Pitkänen, Juhani Puolanne, Matti Pietarila. Ain Lääne, Enn Loigu, Peep Kuslap ja Tiiu Raia

Julkaisun nimi (myös ruotsinkielinen)

Suomenlahden kuormitus vuosina 1982-1984

Julkaisun laji Toimeksiantaja Toimielimen asettamispvmTutkimusraportti

Julkaisun osat

Tiivistelmä

Raportissa tarkastellaan Suomenlahteen Suomesta ja Neuvostoliitosta pistemäisistä lähteistä sekä jokienja ilman kautta joutuvan kuorman suuruutta. Työ on tehty suomalais-neuvostoliittolaisen Suomenlahti—työryhmän siantuntijayhteistyönä._ - Suomenlahteen joutui vuosina 1982-1984 keskimäärin& 800 t a fosforia, 130 000 t a typpeä ja 410 000 t a orgaanista ainetta BOD-arvona. Fosforikuorma kasvoi 8 % ja B0D-kuorma 18 vuosiin 1980-1981 verrattuna. Nousu johtui lähinnä virtaamienkasvusta Neuvostoliiton joissa, erityisesti Nevassa. Typen kuormassa ei 1980—luvulla tapahtunuthuomattavia muutoksia. - Esitetyt ravinteiden kuormitusluvut ovat luultavasti aliarvioita. Tämäjohtuu pääasiassa metodologisista vaikeuksista Suomenlahden ilmeisesti merkittävimmän yksittäisenjätevesikuormittajan, Leningradin. aiheuttaman kuormituksen arvioinnissa. — Toteutetuista vesiensuojelutoimenpiteistä huolimatta Suomenlahteen joutuva kokonaiskuorma kasvoi vuosina 1975-1984.Tämä johtui jokien samaan aikaan kasvaneista virtaamista ja lisääntyneistä huuhtoutumista. -

Tulevaisuudessa Suomenlahden kuormitustutkimusta tulee kohdistaa erityisesti haitallisiinaineimiin. ilmaperäiseen kuormitukseen ja jokien tuomien ainemäärien alkuperään ja käyttäytymiseen.Suoraan jokisuistoihin joutuvan kuorman suuruutta tulee mahdollisuuksien mukaan seurata erilläänjokien tuomasta kuormasta.

Asiasanat (avainsanat)

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

Muut tiedot

Sarjan nimi ja numero ISBN ISSN

Vesi- ja ympäristöhallinnon julkaisuja nro 22 951.47-1807-0 0783-327x

Kokonaissivumäärä Kieli Hinta Luottamuksellisuus29 Englanti Julkinen

Jakaja Kustantaja

Valtion painatuakeskus Vesi- ja ympäristöhallitus

4DOCUMENTATION PAGE

Publiehed Date of public.ation

The National Board of Vatere and the Environanent, Finland

Author(s)

Heikki Pitkänen. Juhani Puolanne. Matti Pietarila. Aine Lääne. Enn Loigu, Peep Kuslap and Tiiu Raja

Title of publication

Pellution load on the Gulf of Finland in 1982-1984

Type ef publication Cominissioned by

Research raport

Parte of publication

Abetract

The report presenta estimated figures and discussion on the pollution load discharged into the Gulf

of Finland from direct point aources and via rivera and the atmoaphere. The york has been conpiled as

a co-operation of scientista and experta from Finland and the USSR under the Finnish-Soviet Working

Group on the Protection of the Gulf of Finland. - During 1982-1984 the Gulf of Finland received on en—1 —1 —1

avarage 6 800 t a of phosphorus, 130 000 t a of nitrogen and 410 000 t a of organic matter as

800. The figuree for 800 and phosphorus were 8 and 18 % higher than during 1980-1981. respectively.

The increaee vas largely due to increased water flows in the Soviet rivers, especially in the River

Hava. Disoharges of nitregen did not increase markedly during the l980s. — The present values

probahly undereatimate the actual nutrient loading. mostly due to methodological difficulties in assessing

disohargea from Leningrad which evidently is the moet significant individual anthropogenic source of loading

by the Gulf of Finland. - In apite of water protection measures and improved waste water

treatment in both countries. the total lead to the Gulf ef Finland increased during the period

1975—1984. due te increaaed water fiows of rivera and increased leaching from land. - In the

future it is iepertant to pay attention to diacharges of haraful su’stances and the role of

atmospheric leading. as veli as to the origins and behaviour of riverine diaharges. Direct

ieading discharged into the estuaries should be monitored Beparately from the riverine load

whenever thia is possible.

Keyvords

Poilution lead. nutrients, organic matter. Gulf of Finland. Baltic Sea. monitoring.

Other information

Series (key titia and no.) ISBN ISSN

Publications of the Water and Environeent 951-47-1807-0 0783-327X

Adainiatration no. 22

Pages Language Price Confidentiality

29 English Public

Dietributed by Publisher

Gevexnment Printing Centre The National Beard of Waters

and the Environment, Finland

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7

CONTENT S

Page

1 INTRODUCTION 92 THE GULF OF FINLAND AND ITS CATCHMENT AREA 103 RIVER DISCHARGES 134 DIRECT WASTE WATER LOAD 145 DEPOSITION FROM THE ATMOSPHERE 196 TOTAL DISCHARGES 207 DISCUSSION 238 FUTURE PERSPECTIVES IN DISCHARGE ASSESSMENTS 25REFERENCES 27

9

INTRODUCTION

In 1978 Finland and the USSR exchanged, under the Finnish

Soviet Working Group on the Protection of the Gulf of

Finland, national information on pollution load discharges

into the Gulf of Finland from the years 1975-1976. This

information was compiled as the first loading report

(Finnish-Soviet Working Group 1979). Since then additional

reports have been published for the years 1977-1979 (Fin

nish-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

Finnish-Soviet Commission 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

Academician Fedorov Institute of Applied Geophysics,

Baltic Branch, Estonian SSR and Estonian Water Management

Agency 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 mee

tings held each year. A 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 Ain Lääne, Enn Loigu, Peep

Kuslap and Tiiu Raja from the USSR. The report has been

edited by Heikki Pitkänen and Juhani Puolanne.

10

2 THE GULF OF FINLAND AND ITS

CATCHMENT AREA

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. As the catchment area is

also rather intensively cultivated, it is evident that

the loading entering the Gulf has strongly increased

from ite natural level. As a result 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 inflow from

rivers (Tahle 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. Locai currents

especially near the coast, can to a large extent be

epiained by geomorphological and meteorolog:Lcai factors.

Loading of nutrients and organic matter primarily affect

productivity and oxygen conditions of coastal waters,As a resuit of density stratification and the input of

organic matter from the surface layer, oxygen conditions

in waters near the bottom are, however, oftexi poor in

the deep water of the Gulf. Great amounte of nutrients,

especially phosphate, are enriched in th.is water iayer,Although being excluded frorn the production cycle of the

surface layer, these nutrients can CiSO cause eutrophicati

on under proper weather conditions via upweiling in nearcoastal waters.

11

Figure 1. The drainage basin of the Gulf of Finland.

12

Table 1-. Morphometrical and hydrological data on the Gulf of Finland

(Falkenmark and ?Iikulski 1974).

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 to the Gulf of Finland. The Finnish values

have been extrapolated to correspond to the whole basins.

River Drainage Examined Mean water flow Annual mean flow;

area; km2 part of during investi- km3/a

drainage gation period; 1982 1983 1984

area; % km3/a

F 1 ni and

Virojoki 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

Mustijoki 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

x) The investigation periods are:

Neva 1859 — 1982 Virojoki 1966 — 1980

Luga 1944 - 1982 Kymijoki 1961 — 1980

Narva 1956 - 1982 Koskenkylänjoki 1961 — 1980

Jägala 1942 - 1982 Porvoonjoki 1963 — 1980

Mustijoki 1966 — 1980

Vantaanjoki 1961 - 1980

Karjaanjoki 1961 - 1980

13

3 RIVER DISCHARGES

Mean values of the period 1982-1984 are presented for

organic matter (BOD7, COD), 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 Koskenkylanj 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, sampies 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

countries.

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.

According 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—1

t a 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 inöluded in the river discharges. In the

lower course of the River Kymijoki loads from several

pulp and paper mills are included in the river discharges

as well.

14

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

River Number of analyses during 1982-1984BOD7 COD N P Suspended

solids

Finland:

Virojoki (4) 14 15 15 15Kymijoki 44 58 47 47 59Koskenkylänjoki 18 37 37 40 39Porvoonjoki 32 34 34 34 34Mustijoki (11) 12 12 12 12Vantaa 33 35 35 35 33Karjaanjoki 33 34 33 34 33

USSR:

Neva 101 45 90 36 46Luga 34 30 12 12 18other rivers 12-18 12-18 12-18 12-18 12-18

4 DIRECT WASTE WATER LOAD

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 m3 /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 treatrnent. In indust

ry, water pollution control was implemented by both process

technical measures and external waste water treatrnent.

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.

Additionally, the treated sewage of some 400 000 inhabi

tants living further upstream contributes indirectiy to

the river discharges.

15

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

River BOD7 COD Tot.N N03-N Tot.P P04—P Suspended. 4)soi ids

Finland

Virojoki_ . . 2 200 140 49 9.1 3.7 1 800Kymijoki 30 000 110 000 6 900 2 600 290 65 55 000Koskenkylänjoki 530 3 100 490 260 33 15 9 300porvoonjoki 1 600 5 300 1 500 900 77 42 21 000l4ustijoki .. 4 200 430 . . 29 . . 9 500Vantaa 1 900 7 300 1 500 850 85 45 27 000Karjaanjoki 650 5 000 580 260 23 8.2 3 300The reat 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

USSR

2)Neva 248 000 2 000 000 49 000 21 000 3 200 1 500 800 000Luga 8 900 109 000 7 000 4 800 280 120 17 7003)Narva 35 000 306 000 .. 9 200 670 290 91 700Jägala 1 000 17 500 930 600 30 10 3 000Investigated small

rivere (summarized) 4 800 52 600 4 400 3 000 200 90 21 000The 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 6G0basin of the Gulf of

Finland

1) including the discharges from several pulp and paper sula2) including the discharges from Leningrad. The nutrient values probably underestimate the

actual loading due to methodological difficulties in sonitoring the Rier Neva belowthe City of Leningrad.

3) including the discharges froiu Narva

4) filter pore size 1 m in Finland and 0.45 pm in the USsR

16

The River Kymijoki Ofher rivers

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

77

7

7-

7i7-

7/ J

7-

7U19 72

700m3 s

300200100

jO’

1200

600•- 400- 200

0

26tlO3t cf10)

16c 12

84

L1970 72 74 76 78 80 82 84

0L)

1970 72 74 76 78 80 82 84

17

t Q•1

80000

60000

40000

20000

0

t a•1

4000

2000

t a300000

250000

200000

______

D

150000

100000

50000

0

Figure 2b. River discharges of organic matter (BOD7) andnutrients from the USSR during 1970-1984.

— TflTIIII

.:::::::

.::-:::. flTmd.-.......17

1

.

PO1I.UII ::::::.:.:.:.:

77-79 80-81 82-841970-72 75-76

The River NevQ

The River Narva

WiIfli The River Luga

The River Jägala

Other rivers

18

Table 5. Direct waste water load of organic aatter and nutrientsFinland in 1982-1984.

to the Gulf of

Source Waste water 2007 Tot.N Tot.Pvolume m3/d t/a t/a t/a

Finland

Municipal discharges:

Helsinki area

Kotka—Hamina area

Porvoo area

Other cornmunities

Industrial discharges:

Pulp and paper industry

in the Kotka—Hamina area

Refinery and petrochernical

industry in the Porvoo area

Other industries

USSR

Municipal discharges:

Tallinn

Vlborg

c.

Industrial discharges:

Pulp and paper industry

in Tallinn

in Viborg

Fertilizer industry

in Maardu

Oil-shale induetry

in Kohtla-Järve’)

Total load to the Gulf of

Finland

329 100 3 270 3430 103

27 000 270 140 15

14 100 150 130 5

24 400 470 230 20

Total load from Finland

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 3800 35018 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

140 500 20 370 (2 330+) (146÷)

Total load from the USSR 483 500 40 800 (6 300+) (518÷)

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

including the municipality

19

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. About 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. As 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.

At 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 mullion m3/d (Veiner 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 polluters on the Finnish

coast were the pulp 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 municipal sewer systems. The pulp and paper industry

in Taliinn and Viborg and the fertilizer industry in

Maardu had their separate sewer systems.

5 DEPOSITION FROM THE ATMOSPHERE

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 Inetitute).

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 TOTAL 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

than in the previous report, covering the years 1980-

1981. No great changes took place in the total input of

nitrogen,

Rivers were the main 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. At 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 arnrnonium, discharges of which could not be included

in this report.

It should be ernphasized that iri spite of the water

21

BOD7 Tot.N Tot.P

600

x 1 03t a•

_____

140 7

_________

x103ta1 ••.r””ix103ta1—r-300 i

____

250 100

_____

5

200 80 4

150 60 3

100 40 2

50 20 1

0 0 01980 1982 1980 1982 1980 1982

—81 —81. -81 —84 —81 —84

1 Direct waste water Ioad

Atmospheric Ioad

River dishorges

Figure 3. Total discharge of organic matter (BOD7) andnutrients to the Gulf of Finland in 1980-1981 and 1982-1984.

22

1200t

-1

1100 ———

1000 -

0-c0.

. 800ft.

700

600

12000t a

11000

10000

- r-

9000-

z8000

7000 -

90000t 01

80000

:::: ----.60000 -

1975 — 76 1977 — 79 1980 — 81 1982 — 81.

Figure 4. The total direct pollution load on the Gulfof Finland during 1975-1984. Broken lines refer to somemissing data.

23

protection measures carried out in both countries

(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. Inthe 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 (Pitkänen 1988).

Atmosphere seems to be an outstanding source of pollution,

especially as regards heavy metals. According 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 discharges from

land has been exchanged since the beginning of 1970’s.

After 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

ye-ars 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

monthiy 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 discharges are mainly dependent

on hydrological factors in different years, as leaching

from land islargely dependent on runoff (Figs. 2a, b),

Howewer, discharges are naturally also dependent on point

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 phosphorus

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 (BOD7) and phosphorus remained constant on the

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 Jgala and Neva Rivers.

The BOD7-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. A slight decrease has also taken place

during the early 1980s. On the other hand direct phospho

rus discharges from pulp and paper industry have somewhat

increased. Industrial nitrogen discharges have clearly

25

decreased from Finland due to water protection measuresin oil refinery and petrochemical industries.

The treatment of municipal sewage has become more effectivein the population centres both on the coast and alongthe rivers flowing into the Gulf of Finland from theFinnish territory. Thus, the transport of phosphorusand organic matter have on an average decreased duringthe 1970s and early l9BQs in the Rivers Kymijoki, Vantaaand Porvoonjoki, although trends in water flows havebeen increasing.

During 1975-1984, and more specifically in the early1980’s, some positive development in the direct wastewater load has taken place, although an increased numberof inhabitants have been connected to sewer networks andthe industrial activities in both countries have increased(Fig. 4). Compared with the 2nd and 3rd reports of theWorking Group on the Protection of the Gulf of Finland,

the total direct BOD7 discharges have been reduced by

11 % and phosphorus discharges by 30 %. This reductionis mainly due to the more effective municipal sewagetreatment (especially BOD7 discharges from the USSR andphosphorus discharges from Finland) and some ,changes inindustrial production and the use of water in industries.

However, the increase of the total direct loading of

nitrogen is inevitable, because nitrogen rmoval is notreally practiced.

8 FUTURE PERSPECTIVES IN

DISCHARGE ASSESSMENTS

So far, mainly traditional discharge parametres havebeen used to describe the pollution load entering theGulf of Finland. There is, however, an increasing needto evaluate and monitor the discharges of harmful substances. Moreover, the origins of loads carried by riversneed to be decsribed more exactly.

To increase the availability of the assessment of pollution

26

discharges to the Gulf of Finland, more emphasis shouldbe given in the research activities to at least the following items:

— Discharges of harmful substances. At present, analytical methods for most of the harmful substances arenot sufficient for routine monitoring. Monitoring ofriverine heavy metais began in Finland in 1982 but theresults are stiil tentative, giving only the magnitudeof the loading. Industrial heavy metal discharges aremonitored in both countries, but there is lack of information on municipal discharges in Finland. There isalso an urgent need for knowledge about the dischargesof various halogenated hydrocarbons and petroleum hydrocarbons in river and waste waters as well as in theatmospheric deposition.

- The effect of sampling frequency on the river transportand the annual variation in the transport. Accordingto the recent studies it seems favourable to f ix thetime of sampling according to hydrological conditionsin a river (e.g. Jumppanen and Kolehmainen 1986 , Loiguet al. 1988). Thus high-flow periods should be muchmore frequently sampled than low-flow periods.

- The role of atmospheric inputs. The loading via atmosphere is important as regards nutrients, but it is ofprimary importance as regards heavy metais and otherharmful and toxic substarices. For example, accordingto the rough estimates given in this report, the deposition values of Pb and Cd are about 20-30 times greaterthan the corresponding riverine discharges from Finland.

- Urban runoff. The magnitude and importance is largelyunknown, but it is probably very important for manypollution load parameters.

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

27

and coastal waters change the pollution load originating

from land both quantitatively and qualitatively.

- 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 be 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 Environment Proceedings no. 17 B, 351 p.

Falkenmark, M. & Mikuiski, Z. 1974. Hydrology of the

Baltic 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 air. Mimeographed reports.

Jumppanen, K. & Kolehmainen, 0. 1986. Nutrient discharge

by the River Aurajoki to the Archipelago 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

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Loigu, E., Kuslap, P. & Leisk, U. 1988. Methodological

aspects for evaluation of poilutants 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, A. & 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.

(in print).

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 significance 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).

29

Skakalsky, B.G. 1988. Up-to-date organic and biogenic

loading in the Gulf of Finland from the Neva

basin. In: Daltic Marine Environment Protection

Commission. The Baltic Sea Pollution Load

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1988. Reprint copy of the statements, p. 170-182.

Veiner, H. 1987. Leningradin vesiensuojelu ja sen vaikutus

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Leningrad and its effect on the Gulf of

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