Gulf of Riga
The catchment area is defined by the drainage basin of the Daugava River extending from Latvia to Belarus and Russia (87 900 km2) and several smaller rivers such as Parnu (5 200 km2), Salaca (3 500 km2), Gauja (8 900 km2) and Lielupe (17 600 km2). The total drainage area of small streams in the coastal areas is some 23 000 km2. The Gulf of Riga is separated from the Baltic Proper by the two islands of Hiumaa (1 225 km2) and Saaremaa (2 650 km2). These islands are important nature reserves and are protected as such.
Pärnu River basin
The Pärnu River basin in Estonia is predominantly agricultural; the main pollution point-sources are the cities of Pärnu and Paide. Pärnu has an old-fashioned wastewater treatment plant, which treats only 65 percent of the total volume of sewage. Pre-treatment of industrial wastewater discharged into the municipal sewage system is practically non-existent. The situation in Paide is similar; about 80 percent of the total municipal sewage bypasses the wastewater treatment station.
In Western Estonia, the next largest city
after Parnu is Haapsalu (population 16
000), which discharges municipal and
industrial (fish processing industry)
wastewater directly to the Baltic Sea. The
existing wastewater treatment plant is
mechanical only and seriously outdated,
Until the Second World War, Haapsalu
was a holiday resort town well known all
over Europe, thanks to the largest deposits
of curative mud in Northern Europe.
Daugava River basin
The two largest cities in the Daugava River basin are Riga, the capital city of Latvia, and Daugavpils. The pollution load originating in these two cities makes up more than 70% of the total municipal wastewater load in Latvia. Altliough both cities have wastewater treatment plants (mechanical treatment only in Daugavpils), they are overloaded by the discharge of industrial wastewaters to the municipal systems, constituting 40-50% of the total amount of wastewater treated. This is in fact one of the characteristic features of municipal sewage systems all over the former USSR. Industrial wastewater is discharged into the municipal sewage systems with little if any pre-treatment, creating severe difficulties, in particular interruption of the processes of biological treatment. In other Latvian cities, wastewater disposal and treatment systems have been built mostly for the local industrial enterprises.
The quality and the level of maintenance of treatment facilities are generally low. In 199 1, completion of the first stage of a new biological wastewater treatment plant in Riga (70-80 percent of total needs), greatly contributed to the reduction of the municipal pollution load. Discharges have been reduced from 35 000 to 1 950 tons/year in BODS and from 58 000 to 3 900 tons/year in COD.
There are several industrial plants in the sub-region, including pharmaceutical, chemical, biochemical and fertilizer plants. While they are often equipped with fairly up-to-date technology, pollution loads are heavy and poorly handled. For instance, the huge Pharmaceutical Industry "Latvbiofarm" in Riga has a wastewater treatment plant, but its capacity is only 25 percent of the actual need. Several types of hazardous waste are generated and all are dumped in nearby forests (groundwater pollution). There are many food processing plants, but most of their machinery is very old and worn out (e.g. yeast factory dating from 1940). Wastewater treatment facilities, if any, are often not functioning and raw wastewater is discharged to the local streams. Although the Vohma meat combine in the Plrnu River basin, for example, has an outdated wastewater treatment plant, the organic load is over twice the original design value.
There is no production of chlorine bleached pulp in Latvia. Pulp is produced in only one integrated pulp and paper mill (Sloka) which discharges its treated effluent to the Lielupe River. The Sloka mill is responsible for 7 670 tons/year of COD discharged to the Baltic Sea. The remaining three mills produce paper only.
The total area of cultivated land in the Latvian part of the catchment area is some 2 000 000 ha (arable land: 1 630 000 ha). Once again, large scale livestock farming is dominant. There are about 30 hog farms with 5000 or more hogs and over 400 farms with 400 or more cattle. Emissions from agriculture and forestry are respectively 40 000 tons/year and 6 500 tons/year in N, and 800 tons/year and 100 tons/year in P.
Rapid eutrophication of the Gulf of Riga. Moreover, the Gulf serves as a huge settlement tank; the rate of deposition of heavy metals is substantial.
Source: The Baltic Sea Joint Comprehensive Environmental Action Programme. Helsinki, 1993. (Balt. Sea Environ. Proc. No. 48), pp. 3-7 - 3-8