Dump Sites


The most important dumpsites in the Baltic Sea are located

  • in the Bornholm Basin
  • in the Southern Gotland Basin and
  • in the eastern Skagerrak

 

Figure 1.1 – Location of the discussed munition dumpsites in the Baltic Sea and Skagerrak. (1) Bornholm dumpsite; (2) Gotland dumpsite; (3) Måseskär dumpsite.

 

Dumpsite in the Bornholm Basin

The Bornholm site is located in the western Baltic, east of the island of Bornholm. Over 35.000 tons of chemical weapons (CW’s) were dumped in water depths ranging between 70 and 120 m. The CW contained an estimated 13.000 tons of toxic agents. Most CW was thrown over board packed in crates or containers, but possibly some ships were also sunk (Helcom 1994, Duursma, E.K. (ed.) 1999).

 

Type of dumped munition


According to the 1994 Helcom report approximately 32000 tons of chemical munitions – containing about 11000 tonnes of chemical warfare agents – were dumped in the Bornholm Basin, east of the isle of Borholm, in water depths ranging from 75 to 95 m (Helcom 1994).

The dumping operations were carried out in 1947 and 1948 on the orders of the Soviet Military Administration in Germany (SMAD). Estimated quantities of munitions and warfare agents were collected from the Russian report submitted to Helcom in 1993 (Helcom 1993a).

According to the Russian figures the munitions dumped in the Bornholm Basin consist mainly of aircraft bombs (72 %) This is of some importance as bombs contain larger amounts of warfare agents and have thinner walls than e.g. artillery shells.

The main types of warfare agents dumped in the Bornholm Basin include mustard gas, Clark I and II, Adamsite and chloroacetophenone (CAP). Most of the munitions contain mustard gas (63 %) and to a lesser extent (31 %) warfare agents containing arsenic (arsenic oil, Clark, Adamsite) (Table 2.1). Based on munitions recovered from the bottom of Wolgast harbour, however, it cannot be ruled out that munitions containing Tabun were also dumped in the Bornholm Basin (Theobald 2001).

Table 2.1 – Types of chemical munitions and quantities of warfare agents dumped in the Bornholm Basin, under control of the former Soviet Union (in tons) (Helcom 1993a).

Types of CM
Mustard gasAs-cont. Adamsite
CAPOthers
Total
Aircraft bombs5.920 906591479-7.896
Artillery shells671-6136-768
High-explosive bombs314----314
Mines 42----42
Encasements80203 693-741050
Smoke grenades--65--65
Containers- 924---924
Drums- -18--18
Total 7.027 20331428515741107


In addition to this amount of 32000 tons, about 200-300 tonnes of CW, discovered after 1952 in the former GDR (East Germany), were dumped east of Bornholm on the orders the East German Authorities between 1952 and 1956 (Helcom 1993c).

Finally, witnesses also report that a further 8000 tons of munitions were dumped in the area east of Bornholm in 1946 on the order of the British Military Administration in Germany (MBAD) (Helcom 1993c). However the latter information was not confirmed by other sources and remains uncertain.

Dumping operation

According to the Helcom 1994 report dumping in the Bornholm Basin was carried out primarily inside a circular area with a radius of 3 nautical miles; the centre of this area is located at 55º21'00N - 15º37'02E (Helcom 1994).

It is known that during transport to the dumping area east of Bornholm munitions were partially thrown overboard while ships were en route. Warfare agents are therefore assumed to be spread over a considerable area along the transport routes (Helcom 1996, Schulz-Ohlberg et al. 2001).

It is generally assumed that the munition dumped east of Bornholm was mainly cast overboard either loose or in containers; the first dumping operations took place while the munitions were still packed in wooden boxes, which sometimes were observed to drift around before sinking to the bottom of the sea (Helcom 1996a).

It is often believed that no complete ships were sunk in Bornholm Basin (Helcom 1996a). However, multibeam and ROV investigations carried out in 2001 have indicated the presence of three shipwrecks. Nevertheless it is not sure if these sunken ships actually transported any war material.

The Bornholm Basin

The Bornholm Basin is an important buffer and accumulation link on the route of the dense salt-water inflow between the Skagerrak and the Gotland Basin (Figure 2.6), and it is the first deep basin where stagnation effects become apparent.

The waters in the Bornholm Basin can be divided into an upper and a lower layer. The upper layer consists primarily of fresh water flowing in from the Baltic Sea with a salinity of 8‰ and reaching down to approx. 50 m. This water flows slowly out of the Baltic Sea. The lower layer originates in the North Sea and on its way to the Bornholm Basin is mixed with water from the upper layer, resulting in a salinity between 9‰ and 23‰. Incoming currents with a salinity of more than 19‰ occur in the period August to April with a mean frequency of every 4-5 years (Helcom 1996a).

More information in WP4: Modelling of migration of toxic compounds and breakdown products 

 



Figure 2.6 – Main currents in the Western Baltic (modified after Emelyanov & Kravtsov 2004). The dashed blue line marks the dumpsite area.

 

Dumpsite in the Southern Gotland Basin (The Gotland Deep)

The Gotland Deep site is located in the central Baltic. At least 2.000 tons of CW was dumped here (some sources mention a total of 40.000 tons) (Duursma, E.K. (ed.) 1999, Granbom, P.P. 1996).

Type of dumped munition

According to the 1994 Helcom report at least 2000 tons of chemical munitions – containing about 1000 tons of chemical warfare agents - were dumped in the Gotland Basin, south-west of Liepaja (Helcom 1994). The dumping operations were carried out in 1947 and 1948 on the orders of the Soviet Military Administration in Germany (SMAD). The estimates of the quantity of munitions and warfare agents were collected from the Russian report submitted to Helcom in 1993 (Helcom 1993a). The main types of warfare agents include mustard gas, Clark I and II, Adamsite and chloroacetophenone (CAP). A detailed overview of the dumped chemical munitions and warfare agents is given in Table 3.1.

Table 3.1 – Types of chemical munitions and quantities of warfare agents dumped in the Gotland Basin, south-west of Liepaja, under control of the former Soviet Union (in tons) (Helcom 1993a)

Types of CWMustard gasAs content AdamsiteCAPOthersTotal
Aircraft bombs512
78
51
41
-
682
Artillery shells58
-
5
3
-
66
High-explosive bombs27
-
-
-
-
27
Mines4
-
-
-
-
4
Encasements7
18
60
-
6
91
Smoke grenades-
-
6
-
-
6
Containers-
80
-
-
-
80
Drums-
-
2
-
-
2
Total608176124
44
6 958

Dumping operation

It is assumed that the munition dumped in the Gotland Basin was cast overboard either loose or in containers.(Helcom 1996a). (Helcom 1996, Schulz-Ohlberg et al. 2001).

According to Helcom the dumping operations in the Gotland Basin, south-west of Liepaja, took place within the following positions: 56º16'N-18º39'E, 56º16'N-18º51'E, 56º20'N-18º55'E, 56º20'N-19º31'E, 56º07'N-19º15'E, 55º56'N-19º15'E, 55º56'N-18º39'E (Helcom 1993c). The dumpsite is located in the southern part of the Gotland Basin, in water depths ranging between 70 and 120 m, north-northwest of the Slupsk channel, which connects the Gotland Basin with the Bornholm Basin.

As was the case for the Bornholm site, the dumpsite boundaries in the Gotland Basin remain rather uncertain. Chemical munitions were most likely spread over a larger area during dumping. Additional spreading of the chemical munitions may furthermore have happened by fishing vessels when trawling. According to the official nautical charts, fishing in the Gotland dumpsite area is not prohibited.

 

Dumpsite in the eastern Skagerrak (Måseskär site)

Måseskär site is located in the eastern Skagerrak, 25 km off the Swedish coast. At least 8 ships were sunk here in a water depths ranging between 180-200 m. According to reports roughly 30.000 tons of toxic agents were dumped (Fonnum, F. 1993, Granbom, P.P. 1996).

Type of dumped munition and mode of dumping operation

Between 1945 and 1947 (possibly up to 1948) at least nine ships - eight naval vessels and one medium-sized cargo vessel - were sunk in the eastern Skagerrak, 8 nautical miles west of the Måseskär lighthouse. The ships were scuttled in water depths ranging roughly between 180 and 230 m.

The dumping operation was carried out on the orders of the British and American occupation forces (Helcom 1994). The quantity of chemical munitions was estimated by Swedish authorities to be approximately 20000 tonnes, among others containing mustard gas; the presence of other types of chemical warfare agents, including nerve gas, was not verified but cannot be ruled out (HELCOM 1993b).

It was confirmed by United Kingdom that ships with chemical munitions were sunk in this area (Helcom 1993i), but no information about quantities and types of chemical munitions could be obtained. Assuming that the ships that were scuttled were loaded to 90 percent of capacity, the total amount of warfare dumped near Måseskär could have been as much as 55000 tons according to some authors (Laurin 1997 and references therein).

Missiaen, T., Paka, V., Emalyanov, E. (2006)
Photos: Shirshov Institute of Oceanology (2006)

 
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At least some
50,000 tonnes
of chemical
weapons were
dumped in the
Baltic Sea.