Pesticide Poisons the Rhine River

The dumping of a potent insecticide into the Rhine River killed an estimated fifty million fish and led to an international dispute. The disaster led to calls for clearer communications between the Rhine countries and for more stringent pollution controls.

Summary of Event

Large numbers of dead fish were found in the Rhine River on June 19, 1969. The scale of the catastrophe became evident over the next few days, as millions of fish floated to the surface and washed ashore or downstream. It was not immediately apparent what had caused the disaster. Large numbers of scientists in Germany and the Netherlands, as well as on two research ships on the river, went to work to identify the contaminating material. Late in the day of June 24, the material was identified by chemists from the Dutch Institute of Public Health as an insecticide. Within two weeks, the bulk of the material had washed out to sea, leaving in its wake a river virtually devoid of fish. Pesticides
Pollution;West Germany
Hazardous materials
Ecological disasters
[kw]Pesticide Poisons the Rhine River (June 18-26, 1969)
[kw]Rhine River, Pesticide Poisons the (June 18-26, 1969)
Pollution;West Germany
Hazardous materials
Ecological disasters
[g]Europe;June 18-26, 1969: Pesticide Poisons the Rhine River[10280]
[g]Germany;June 18-26, 1969: Pesticide Poisons the Rhine River[10280]
[g]West Germany;June 18-26, 1969: Pesticide Poisons the Rhine River[10280]
[g]Netherlands;June 18-26, 1969: Pesticide Poisons the Rhine River[10280]
[c]Environmental issues;June 18-26, 1969: Pesticide Poisons the Rhine River[10280]
[c]Disasters;June 18-26, 1969: Pesticide Poisons the Rhine River[10280]
[c]Chemistry;June 18-26, 1969: Pesticide Poisons the Rhine River[10280]
[c]Agriculture;June 18-26, 1969: Pesticide Poisons the Rhine River[10280]
Deneke, Diether
Bakker, J. A.

At the time of the incident, the Rhine was already notorious for the extremely polluted state of its waters. This high level of pollution could be attributed to several causes. Flowing a distance of approximately 800 miles through one of the most heavily industrialized regions of Europe, the river was used for the discharge of a variety of substances, including waste from steel mills and coal mines from German industries and tons of salt waste from potash mines in France. In addition, runoff waters from agricultural regions in the Rhine Valley carried agricultural chemicals into the river. At the time, it was taken for granted that more than one thousand foreign substances were present in the river at any given moment, so that the Rhine had earned the dubious distinction of being the longest sewer in Europe. This made identification of any single agent a difficult task.

Another factor contributing both in general to the contamination of the river and specifically to the 1969 insecticide spill was the large concentration of shipping, particularly barges, present at all times on the river. This traffic was indicative of the key role played by European waterways in commerce and transportation.

High pollutant levels had already resulted in the loss of many indigenous species from the river, such as the Rhine salmon. Swimming in the river was generally perceived as an unwise activity.

All these problems were exacerbated by the complicated politics required to establish any uniform international policy to regulate the river. The Rhine flows through or along the borders of Germany, Switzerland, France, and the Netherlands on its way to the North Sea. One result of this situation was that no set of consistent regulatory policies had been established for the Rhine. In addition, there was no clearly defined or generally acknowledged procedure for one country to rapidly notify the others of any incidents on the river that would affect those neighbors downstream.

In this period of lax regulations and poor communications between neighboring parties, the stage was set for an event such as that of June, 1969. On June 19, a Thursday, the first evidence that there had been a mishap appeared in the form of dead fish floating to the surface near Bingen in the Rhineland-Palatinate state of West Germany. Over the next few days, more fish were killed. Later estimates placed the number of dead fish and eels at an astronomical fifty million. By June 24, the effects of the contaminant were noted as far as 200 miles downstream. As the source of the kill drifted downstream, officials and workers in West Germany were trying to determine the point at which it originated. The area in which the kill was first noted was not an industrialized area, ruling out industrial sources. This was confirmed when it was found that no effect was noted in industrial areas farther upstream.

The point at which the material was introduced into the river was determined to be near the city of St. Goar, slightly upstream from Bingen in a part of the country noted for wine production. Such an inconspicuous location caused investigation to shift toward river traffic that had passed through the area on June 18, with speculation being that the material was either deliberately dumped or inadvertently dropped overboard from a passing barge. While this became the generally accepted cause of the spill after subsequent investigation, conclusive identification of the individuals involved was never obtained.

Dutch chemists were the first to identify the material, announcing that it was an insecticide called Endosulfan. While used to spray vineyards and orchards in the area, the large concentration present in the river was consistent with roughly two hundred pounds of the material being spilled, an amount inconsistent with agricultural runoff. This particular material is extremely toxic to fish, which explains the massive quantity of fish killed by a relatively small amount of material compared to normal industrial discharges into the river.

Waterworks in Germany at points downstream from St. Goar rapidly set up tanks stocked with trout to monitor water supplies. Similar steps were taken at reservoirs. Contamination of German drinking-water supplies was not a problem, as drinking water was not drawn directly from the river itself but from reservoirs or groundwater sources near the river.

The only other country directly affected by the spill was the Netherlands. In many ways, the effect on this country was more severe, as several major Dutch cities drew their drinking-water supplies directly from the Rhine rather than from wells or reservoirs. The Netherlands also contains a system of canals to provide both an outlet for the Rhine and protect the countryside from flooding. As a result of poor communications, the Dutch government was not officially notified of the spill until shortly before it reached the border. Purification plants in the Netherlands were rapidly closed off from the river and shipping locks were closed.

The bulk of the insecticide had washed out to sea within a week of the incident. While fish placed in water from the river lived for only seven minutes on the following Monday, within a few days the pesticide level was low enough for fish to survive. The large number of decaying fish in the river caused a brief decrease in the water’s oxygen content, but this rapidly returned to normal as the natural flow of water purged the river. Large numbers of fish were burned as the only practical means of disposal, and it was speculated that several years would be required to restore the river’s population to that existing prior to the spill. Total monetary impact of the event, as a result of both loss of fish and the cost of purification plant shutdowns was estimated to be approximately $1 million. Restoration efforts were initiated rapidly, as the West German government announced the purchase of fish from hatcheries to be placed in the Rhine tributaries on August 29.


Although the International Commission for the Protection of the Rhine International Commission for the Protection of the Rhine had been established in 1963, the 1969 incident showed that apparently no real progress had been made in establishing acceptable guidelines for minimizing pollution in the river and in communicating warnings of hazardous conditions between the countries involved. The Dutch government claimed negligence on the part of the Rhine-North Westphalia government, claiming official warning of the imminent disaster was received scant hours before the contaminant entered its country.

J. A. Bakker, the minister of transport and waterways for the Netherlands, officially announced to Parliament that West Germany would be held responsible under international law for damages resulting from the incident. The West German state agricultural minister, Diether Deneke, responded that a warning had been sent the previous Friday to all relevant German waterworks with the understanding that it would be passed on; however, it was not. The warning was received in time to prevent contamination of drinking-water supplies in the Netherlands. The Dutch were vigorous in their probe as to the identity of the agent as evidenced by the fact that they correctly identified it before any German announcement was made.

The official West German press release on the fish-kill was made on the same date that the secretary-general of the United Nations, in a speech, warned member nations of the growing pollution problem worldwide and called on nations to join forces to decrease air, water, and land pollution. In the immediate wake of the incident, calls for clearer communications between the Rhine countries and for more stringent pollution controls were made. The magnitude of the fish-kill jolted people into the awareness that the next spill could be of a substance more toxic to human life.

Within a year of the incident, the West German government, under the leadership of Chancellor Willy Brandt Brandt, Willy , established a department to spearhead antipollution programs. Stimulus for the formation of this department was a result not only of growing awareness within West Germany but also of the growing antipollution movement in the United States. Plans included construction of several new effluent treatment plants, formation of international antipollution funds, and exploration of alternative methods of solid waste disposal. Other countries were stimulated by the incident to implement similar projects as well as to develop stronger antipollution measures and more effective warning systems. The Netherlands in particular established a program of continual monitoring of the Rhine River at the border to provide rapid warning of potentially hazardous conditions.

Awareness of deliberate dumping of substances into the Rhine was heightened during this period, and this suspicion with respect to the Endosulfan was not without some justification. Within a few months of the Endosulfan incident, several German barge captains and a shipping company owner were tried, convicted, fined, and given jail sentences in Kleve. They were accused of dumping caustic soda into the Rhine rather than in designated areas of the North Sea between 1965 and 1968.

In spite of greater sensitivity to the pollution problem in the Rhine, within two years the river had reached a level of pollution as high as that in 1969. Massive fish-kills occurred in two of the Rhine’s tributaries in May, 1971, and were attributed to both a sharply reduced flow of water as a result of dry weather and high pollutant concentrations resulting from the discharge of an industrial site. Efforts to make legal claims in this case were hampered again by the problem of jurisdiction, making it difficult to claim damages.

Active efforts to reduce the pollution level continued into the mid-1970’s, although the net effect was simply to prevent the level from increasing. An economic recession during this time period also hampered efforts. By 1976, increasing environmental awareness coupled with concern about nuclear power plants resulted in German and French citizens becoming much more active in protesting government policies that were detrimental to the environment. This increased public awareness culminated with the signing of three treaties between the European Economic Community and the Rhine nations in late 1976. The treaties’ goals were to minimize waste discharges into the river and to coordinate international legislation dealing with the river. Over the course of the next decade, real progress was made in improving conditions on the Rhine. Disaster, however, would strike again in the aftermath of a fire in a chemical storage warehouse in Basel, Switzerland, in 1986. Pesticides
Pollution;West Germany
Hazardous materials
Ecological disasters

Further Reading

  • Bierlein, Lawrence. Red Book on Transportation of Hazardous Materials. 2d ed. New York: Van Nostrand Reinhold, 1988. A useful background reference. Discusses United Nations regulations on the transportation of hazardous materials.
  • Cioc, Mark. The Rhine: An Eco-biography, 1815-2000. Seattle: University of Washington Press, 2002. An environmental history of the Rhine River that covers its ecology and biodiversity, engineering projects along the river, environmental regulations, river restoration, and more. Includes maps, a bibliography, and an index.
  • Layman, Patricia E. “Rhine Spills Force Rethinking of Potential for Chemical Pollution.” Chemical and Engineering News (February 28, 1987): 7-11. A well-written article outlining the actions taken by European chemical manufacturers in the immediate aftermath of the Basel spill in 1986. Of particular interest relative to the Endosulfan spill is an overview of legal measures implemented as a result.
  • Pallemaerts, Marc. Toxics and Transnational Law: International and European Regulation of Toxic Substances as Legal Symbolism. Portland, Oreg.: Hart, 2003. Part of the Studies in International Law series, this study analyzes pollution and its regulation as a “transboundary” concern. Includes the introductory chapter “Transboundary Pollution of the Aquatic Environment by Toxic Substances from Industrial Processes and Products: The Problem and Its Perception.”
  • Pearce, Fred. “Greenprint for Rescuing the Rhine.” New Scientist 138 (June 26, 1993): 25-29. An excellent article outlining the history of the Rhine in terms of channel control and industrial development. Describes major changes in the river’s behavior and ecosystem resulting from these pressures. Focuses on the growing awareness that environmental restoration may be a more effective means of restoring the Rhine than merely relying on pollution reduction and legislation.
  • Schwabach, Aaron. “Death Watch on the Rhine.” Business and Society Review, no. 75 (Fall, 1990): 36-40. Written four years after a warehouse fire in Basel caused a major toxic spill into the Rhine. Gives a brief overview of the event and an excellent description of the aftermath. Also includes a partial listing of the 1976 Rhine Treaty and how the governments involved failed to implement the agreements.
  • Shoemaker, Ted. “Impetus for Action.” Science News 96 (July 19, 1969): 64. A brief article giving a concise overview of the 1969 environmental disaster along the Rhine and the immediate aftermath. Includes a good general description of the chemical and physical nature of Endosulfan, the contaminating material identified in the incident.

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