Ammonia release into the Mediterranean and coastal cities

[nomadreid]

There is a dispute going on in one of the cities (which will remain nameless for this question, so as not to get political) on the Mediterranean about the following: there are about 120 thousand tonnes of ammonia imported by ship to this city every year (mostly for the production of fertilizer), with a shipment of 10,000 tonnes once a month, docking at this city's port to unload the cargo to the storage facility. The ship carries ammonia to other countries as well, each shipment containing 16,700 tons of liquid ammonia as it comes to this city's ports. The storage facilities have been designed with extra safeguards against earthquakes, small rockets and everything except a direct hit with a large rocket. The problem is that this city is a target for such rockets; the ship would also be in range of the rockets. So people are worried, but the engineers say that the danger is not as much as the press claims. Anyway, it is clearly a danger for the people of the coastal city if there is a direct hit on the tanks, especially around the port, but my question is not about that. Rather, there is the question as to what happens if one or more of the tanks on the ship are hit and its 3,340 tonnes of liquid ammonia spill into the Mediterranean near the city. What would be the resulting danger to the humans of the city, and the marine life?

 

[phinds]

... each shipment containing 16,700 tons of liquid ammonia as it comes to this city's ports.

what happens if one or more of the tanks on the ship are hit and its 3,340 tonnes of liquid ammonia

Seems there would at least be some difference based on which number is correct.

 

[nomadreid]

phinds, thanks for the reply. "Its" refers to one of the tanks (16,700 /5) not to the whole ship. The "or more" was rather poorly placed there. (Also, a typo, as "tons" should have been "tonnes". )

 

[phinds]

Got it. Well, the first thing that comes to mind is that it sure would be tough on the local fishermen.

 

[nomadreid]

The local individual sporting fishermen are located on another beach a long way away from the port, where it is nicer to fish, and they don't usually catch anything anyway. The fishermen (fisherpeople?) who provide the city with fish are in boats the size of my apartment block further out into the Med. But that is a question: whereas more than 0.02 mg/l (ppm) in water is considered harmful, the exposure has to take some time before doing its harm, so that fish in the immediate vicinity of the boat (or, if there were an emergency evacuation of the land-based tanks into the water, which is part of an emergency plan, in the immediate vicinity of the dumping site) would not appreciate it, but the stuff that stayed in the water (not sure how much stays in the water, how much goes out as gas light enough to get out of harm's way of the humans, and how much will go out as vapor that stays around ground level and drifts over to the port city) would get diluted pretty quickly. (As far as humans and the gas/vapor, the debate here goes between assertions that there is no danger to humans, citing the lack of Bhopal-type catastrophes based on ammonia, to assertions that the whole population of the city could die. I have not been able to see the detailed reports that supposedly back up the extreme claims, so I am asking here.)

 

[jim mcnamara]

Ammonia does not spill, at room temperature and air pressure it is a gas. It was used as a poison gas during WWI. It would have some effect on the water, but mostly it would kill everything downwind of the explosion until such time as the aerial concentration fell below the LD₅₀ level. So wind direction is very important. Hazmat procedures for fire departments in the US cover topics like evacuations, etc.

Look at LD₅₀ values as function of atmospheric ppm NH₃ and time of exposure.
Any exposure to people with pre-existing pulmonary conditions, like asthmatics and people with COPD, is cause for alarm.

https://en.wikipedia.org/wiki/Ammonia
Density of ammonia .86/kg/m³ is less than air so it will tend to rise in calm air.

I cannot give you a realistic answer - the result could be minimal, some dead sea birds, or awful if a large beach resort was downwind and this occurred at noon.

 

[jim mcnamara]

This was ammonium hydroxide aqueous solution - hazmat response and evacuation

http://www.azcentral.com/story/news...ona-evacuated-buckeye-ammonia-smell/96148208/

 

[rbelli1]

3,340 tonnes of liquid ammonia going poof would tend to reduce the local temperature quite dramatically. I would expect some amount of liquid ammonia finding its way into the ocean from a ship. What happens when liquid ammonia hits Mediterranean temperature seawater? Does any appreciable amount dissolve before it boils off? It will tend to float with a density of about 66% of seawater.

BoB

 

[jim mcnamara]

The BP of liquid ammonia −33.34 °C, well below normal air temps for the Mediterranean area. Liquid ammonia is not going to Kumbaya along on its way to the gaseous phase. I would expect rapid change of phase.
Except near ground zero, the real danger is not always lethal doses because the vapor diffuses and blows away, but the downwind medical aftershock to healthy pulmonary systems. Unhealthy pulmonary systems are in big trouble. Eye damage is also a concern. That stuff is really nasty. There is some kind of required evacuation perimeter, winds are taken into account. I do not know what that would be anymore. If I ever knew.

I would guess @berkeman has had hazmat training on the whole subject. Hopefully, he can be more definitive than my out of date knowledge.

Try this: https://www.atsdr.cdc.gov/mmg/mmg.asp?id=7&tid=2

 

[nomadreid]

Thanks to all the contributors; I have read the sites provided, and all in all it appears that the local newspapers in the port city described as well as the local politicians and the private firms involved are exaggerating (in opposite directions) the risks and talking through their hats on the certainty they have of the outcomes and the risks. That is, from the information given, it appears that the risks are not negligible, but nonetheless remain incalculable.

 

[256bits]

3,340 tonnes of liquid ammonia going poof would tend to reduce the local temperature quite dramatically. I would expect some amount of liquid ammonia finding its way into the ocean from a ship. What happens when liquid ammonia hits Mediterranean temperature seawater? Does any appreciable amount dissolve before it boils off? It will tend to float with a density of about 66% of seawater.

BoB

Depends on the rate of leakage - ie the size of the "hole" from the tank as to the vapour/ liquid ratio.
A small leak would allow heat transfer for complete vapourization.
Larger leaks would initially vapourize until such time surroundings and the liquid achieve thermal equilibrium at atmospheric temperature. Since the vapour formation continues the pool of liquid can achieve temperatures well below the boiling point at a atm.

Ammonia with water forms NH₄OH, raising the pH of the water, a rapid and exothermic reaction. Boil off of liquid ammonia in water releases a percentage of gaseous form that enters the atmosphere.

The best site for info on release on the ground.
http://www.aristatek.com/newsletter/0602February/TechSpeak.aspx

A study for release on or in water.
Prediction of Hazards of Spills of Anhydrous Ammonia on Water

Exposure guidelines
https://www.epa.gov/aegl/ammonia-results-aegl-program
from
https://www.epa.gov/aegl/access-acute-exposure-guideline-levels-aegls-values#chemicals
if you want to look at other substances.

some more from the CDC, occupational health and emergency response
https://www.cdc.gov/niosh/ershdb/emergencyresponsecard_29750013.html

 

[nomadreid]

Good references, 256bits. Thanks!

 

[256bits]

Thanks to all the contributors; I have read the sites provided, and all in all it appears that the local newspapers in the port city described as well as the local politicians and the private firms involved are exaggerating (in opposite directions) the risks and talking through their hats on the certainty they have of the outcomes and the risks. That is, from the information given, it appears that the risks are not negligible, but nonetheless remain incalculable.

They parties are most likely talking about different risks.
Generically, it is something like this:
The company would be expressing that the chances of a particular size of spill has a certain probability to occur, with larger spills ( such as rupture of the tank ) less likely to occur than smaller spill ( such as a pipe connection failure ).
Newspapers could be attempting to sell papers by expressing the worst possible ever scenario to their readers.
Readers would access the "facts" and conclude that they are not 100% safe and feel unease.
A politician could either side with the company, or the readers, ( and maybe analyze the best choice for re-election, but they are human too so that is not necessarily so ), and frame his/her responses in an applicable manner.

Everyone knows there is a problem, just how big of a problem is the discussion and for everyone to agree upon.

 

[nomadreid]

Newspapers could be attempting to sell papers by expressing the worst possible ever scenario to their readers.
Readers would access the "facts"

Indeed, the problem with assessing the facts is that the newspapers in this Mediterranean country often (as in this case) do not give proper references for their statements. The hullabaloo started when a chemist at a local university made a report to a government body in which, according to him, he "showed" that the whole city was in danger of being killed either by the ammonia in the land-based storage tank, comparing it to an atomic attack, something that the newspapers took up, without giving any specifics, and expanded the danger to include the ships. Since I could not get hold of the original report, I could not judge the basis of his claims (except from some inside information from the engineer who designed the storage tank and who explained to me the construction of the tank, supporting his claim that at least as far as the storage tank was concerned, there was no reason for concern. But he didn't publish his plans for the general public, and he could not comment on the ship's containers.) Between these two positions, the responses on this forum were more nuanced and thus highly welcome.