Styrene, more dangerous than expected

2000/11/07 Roa Zubia, Guillermo - Elhuyar Zientzia

• Ingurumena

In last week's accident near Normandy, the ship Ievoli Sun issued 6,000 tons of chemical substances to the sea. Of these, one thousand tons of methyl etil ketone and another thousand tons of isopropanol. These two compounds cannot be considered toxic. To be lethal for fish, dosages 3 and 10 g/l are required, respectively. However, it will be necessary to reflect on whether the instant discharges cause ecological imbalances.

The other 4,000 tons are very worrying. In fact, it has remained in the sea a large stain of styrene very used in the manufacture of polymers. Styrene is considered a care compound in any laboratory. In view of how the molecule is, the chemicals assimilate it to carcinogenic substances.

Attack on marine life

It should be noted that a concentration higher than 10 mg/l is lethal for fish. This data is nothing relaxing. At least as if it were oil, the spill has been floating because the styrene is less dense than sea water. This characteristic can be of great help, since the molecule is very volatile and therefore easily detectable. However, this does not mean that it is not a dangerous substance. On the other hand, the molecule is biodegradable. Therefore, it is not considered as one of the most violent pollutants. It has serious consequences, but it is an unsustainable molecule. In fact, in the scale of toxicity from «A» to «D», the styrene «B» has been given.

Another predictable process is polymerization. When this occurs, the reaction produces a solid white. This solid would have the same effects as plastics in the environment. However, polymerization is not easy as it requires other compounds and is usually transported along with inhibitors of this process. In addition, other side reactions may occur due to the action of sunlight. Unexpected ecological consequences can come to light in the long term. The accident of the oil tanker Erika, which occurred a year ago, caused another type of deterioration, undoubtedly more serious. However, the effect of the spill of the Ievoli Sun is not yet known and we know what we will have to expect. For what we analyze, it may be late for some ecosystems.