5.1.1 Toxicity
In general, there are three distinct routes by which toxic substances can enter the body; via the digestive organs, via the skin, via inhalation. Uptake through the respiratory organs is the result of inhalation of toxic substances and is the most important hazard to human life to be considered. Uptake through the skin and via the digestive organs is not considered a serious hazard to responders at sea but could be relevant on board the ship in distress with chemicals on board.
Toxicity by inhalation
The toxicity by inhalation is the ability of a material to cause damage to living tissue above the water surface, impairment of the central nervous system, severe illness, or in extreme cases death when inhaled. An appreciable number of the wide range of industrial chemicals regularly transported by sea could form poisonous gas plumes if released to the environment. The presence of such plumes would pose a considerable threat to all those in the area.
For most substances, maximum exposure limits are set, such as the MAC value and the TLV value. MAC stands for Maximum Acceptable Concentration, and is an indicator of effects of long-term exposure. In an atmosphere with concentrations below the MAC value, a worker is able to work full workweeks of 8-hour days without experiencing adverse effects of the exposure. Thus, substances with a concentration lower than the MAC value will not be dangerous to anymore. TLV (Threshold Limit Value) has a similar definition but is more commonly used in the United States.
The GESAMP profile lists mammalian toxicity in columns C1, C2 and C3. In case of a toxic environment, the only way to avoid the adverse effects is by using the correct personal protection equipment.
Toxicity by ingestion
A substance can also be toxic by ingestion. Generally this contact route is not very relevant for spill responders. It can however be more important when a substance is spilled near a location where there is a lot of tourism (swimming).
Toxicity by skin absorption
Like toxicity by ingestion, toxicity by skin absorption is also not immediately relevant to responders at sea case of a spill. But could be a treat on board of the distress vessel.
For most substances dermal toxicity is linked to toxicity by ingestion, in the sense that substances that are toxic by ingestion are also toxic by skin adsorption, and substances that are not toxic by ingestion are also not toxic by skin adsorption.
