Lessons Learned From The Sandoz Disaster

Circled in red is the site of the 1986 Sandoz disaster.
Circled in red is the site of the 1986 Sandoz disaster.

In 1986, on the border of Switzerland and Germany, 1350 tonnes of highly toxic compounds suddenly went up in flames at a warehouse belonging to Sandoz (now part of Novartis). The fire brigade responded promptly and put out the fire in about five hours. But to do so they used millions of liters of water. Due to inadequate catch basins at the factory, 20 tonnes of a pesticide-brew tagged along and flowed into the Rhine. Eventually within a couple of weeks, along a 400 km path, fish and birds were killed, and so were most of the eels in the river. The Ijssel River as far as the Netherlands was affected, even though they closed floodgates. Initially a Sandoz spokesperson had dismissed the 70-km long red slick as “a harmless dyestuff” Understandably the safety director of the company was later pelted with dead eels by protestors.

The most problematic compounds in the mixture released into the river were dinitro-orthocresol, propetamphos and parathion. Until 1991, the first compound was used as a pesticide. It’s toxic to aquatic organisms at low concentrations(0.07 to 5.7 ppm). The latter two are organophosphate pesticides, which are cholinesterase inhibitors and which are also moderately to highly toxic to fish. Parathion, specifically, is lethal after 96 hours of exposure to 50% of fish at concentrations ranging from 0.02 to 2.7 ppm, depending on the species.

As a result of the public outcry from the disaster, the Rhine Action Program came into effect in the following year. It set goals to cut 1985 discharge levels by half. It increased safety regulations for industries. Adequate catch basins had to be set up to prevent leaks into the river. Spawning grounds for salmon had to be restored in the Rhine’s tributaries with the hope of having salmon again in the river by the year 2000. Finally, shoreline ecosystems had to be revived with indigenous species. Fourteen years later, three years ahead of schedule, salmon returned to the Rhine. Nitrates and phosphate levels were cut by 50% and there was a 80 to 100% reduction in some other forms of water pollution.

A second program came into effect in 2001 when the ministers in charge of the Rhine adopted “Rhine 2020“. Here’s an outline of its main goals.

(1)The presence of salmon in the Rhine is still dependent on human intervention. One aim of the new program is to get wild salmon from the ocean to return and to increase population to self-sustaining levels.

(2) A second commendable goal is to keep improving water quality. A number of target values have been set, and currently the elements and compounds whose concentrations are still above desired levels are copper, cadmium, zinc, diurone and benzopyrene. Diurone was a mercury-based diuretic Benzopyrene is a group 1 carcinogen formed from the combustion of oil, wood and tobacco.

(3) Since lowered groundwater tables  pose a problem in parts of Moselle/Saar, the Lower Rhine and the Delta Rhine, in particular in mining zones, Rhine 2020 also aims to protect drinking water in those areas.

Here in Quebec, we have something comparable to the Rhine 2020 program known as the St. Lawrence Action Plan, but unfortunately it does not include specific goals with regard to reducing contaminants. And yet the sediments of the St.Lawrence are moderately contaminated as revealed by this 2012 map:

from http://planstlaurent.qc.ca/en/state_monitoring/overview_of_the_state_of_the_st_lawrence_2014.html#c2747
from http://planstlaurent.qc.ca/en/state_monitoring/overview_of_the_state_of_the_st_lawrence_2014.html#c2747

beluga-whale_458_600x450We also have a serious problem with belugas, whose population in the gulf of the St. Lawrence River has declined from 8000 individuals in 1920 to 886 in 2012,  Hunting of belugas was banned in 1979, yet the species continued to suffer. Although the concentration of many contaminants declined, there was a doubling of PBDE levels in male belugas between 1985 and the 2000s. PBDEs are polybrominated diphenyl ethers, compounds used as flame retardants in many household goods. A number of toxicological studies have demonstrated that exposure to PBDEs may have critical endocrine disrupting effects during fetal development of belugas. Biologists realize that a number of other stress factors are involved, many of which are, however, also caused by mismanagement of the river. For instance, toxins released by some algal blooms could very well be involved. There were also 334 spills involving ships in the St. Lawrence River between February 2002 and November 2012. Meanwhile Environment Canada is at least currently considering prohibition of PBDE compounds.

BMAA and ALS: A Close Look at Eutrophication

The overall equation representing one of life’s ultimate achievements, photosynthesis, is the biggest oversimplification you will find in any basic science book on the planet. It shows water, carbon dioxide and sunlight as reactants and glucose and oxygen as products. It does not hint at the intricate cascade of events that have to transfer electrons from water to carriers to chlorophyll; on to more carriers and other chlorophyll molecules and still more shuttle bus-like molecules and eventually to carbon dioxide and other reactants of the Calvin cycle.

From http://www.biologyreference.com/Ph-Po/Photosynthesis.html
From http://www.biologyreference.com/Ph-Po/Photosynthesis.html

It overlooks the accessory pigments that help chlorophyll capture more energy from the sun. It ignores the components of the membranes that separate hydrogen ion concentrations supplying the voltage needed to make the reaction facilitator, ATP, and all the enzymes that accelerate the entire food-making process of plants.

Reaction rates in chemistry are controlled by their slow intermediary steps. Photosynthesis and subsequent plant growth rates are controlled by the amount of light, which initiates the process; by temperature, which controls the carbon-dioxide fixing rate; by water-availability and by certain limiting ions. In other words, there is usually ample carbon dioxide available, but other minor, yet crucial substances are often scarce and control the growth of both land and aquatic plants. For algae, such limiting ions, mainly phosphate(PO43- and nitrate(NO3) are needed to make those behind the scene-molecules just mentioned: nitrogen-containing enzymes and ATP, which have N-compounds and phosphate, and they are also needed to synthesize genetic material.

But what happens when limiting ions suddenly become available in greater quantities to bodies of water? They cause eutrophication, which is a state of excess plant and algal growth. Although the process can occur naturally, humans are masters at accentuating it. Runoff fertilizer from nearby agricultural activities, sewage and industrial effluents all contain nitrates and phosphates, which directly lead to population explosions of algae, so called algal blooms.


As algal growth goes out of control, light has a harder time penetrating the water and its pH rises, both of which impact certain predators and shore plants. When excess algae die as part of their life cycles, their decomposition consumes dissolved oxygen, killing fish. Such hypoxic events are affecting over 245 000 square kilometers worldwide.

The foul smell of algal blooms is also a sign of more chemistry gone awry. Depending on the algal species that proliferate, eutrophication at times produces toxins that threaten drinking water supplies, recreational swimming and consumption of seafood. More specifically species of a group of photosynthetic bacteria, cyanobacteria,  produce compounds such as an enzyme-binding microcystin and the neurotoxin anatoxin-a, which mimics the neurotransmitter acetylcholine.

One of several microcytins, the LR refers to variant amino acids
One of several microcytins, microcystin-LR— the LR refers to the variant amino acids leucine and arginine.

In Canada, the Federal-Provincial-Territorial Subcommittee on Drinking Water recommends a maximum acceptable concentration of 0.0015 mg/L for total microcystins in drinking water, based on the toxicity of microcystin-LR. That is equivalent to 1.5 parts per billion, attesting to their high toxicity and to the fact that these compounds resist boiling.

Another cyanobacterial neurotoxin , β-methylamino-ʟ-alanine (BMAA), found in contaminated seafood and shellfish, drinking water supplies, and recreational waters—may be a factor in Lou Gehrig’s disease (amyotrophic lateral sclerosis, or ALS) and possibly other neurodegenerative conditions.


The toxin is produced by 95% of the cyanobacteria genera tested, and although it is not one of the 20 amino acids building blocks used by organisms, it does get mistakenly incorporated into proteins.

Accumulation of BMAA in the proteins of nerve cells, which need to last a lifetime, would provide a mechanism for how the toxin might biomagnify. “The problem with neurons is they do not divide, as a general rule, so over time they accumulate damaged proteins, and once they reach a critical level, it causes the cell to undergo apoptosis [cell death],” explains Rachael Dunlop, a researcher with the Heart Research Institute in Sydney, Australia.

Dunlop and others also found that at least in test tubes, a transfer RNA enzyme mistakenly picks up BMAA and incorporates it into proteins. More recently Dunlop and another researcher have mentioned that genes in certain individuals make them more sensitive to BMAA, which unfortunately is not presently screened for in municipal water analyses.


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