The Pacific Ocean Is Polluted With Coffee

An anonymous reader writes in with this excerpt from Inhabitat:"People aren't the only ones getting a jolt from caffeine these days; in a new study published in Marine Pollution Bulletin, scientists found elevated concentrations of caffeine in the Pacific Ocean in areas off the coast of Oregon. With all those coffee drinkers in the Pacific Northwest, it should be no surprise that human waste containing caffeine would ultimately make its way through municipal water systems and out to sea – but how will the presence of caffeine in our oceans affect human health and natural ecosystems?"

Comments

Metabolites and half lifes

[icebike]

Wiki says

Caffeine is metabolized in the liver by the cytochrome P450 oxidase enzyme system (to be specific, the 1A2 isozyme) into three metabolic dimethylxanthines. Further, In healthy adults, caffeine's half-life has been measured with a range of results. Some measures get 4.9 hours, and others are at around 6 hours.

Therefore, it seems unlikely that the source of caffeine in the ocean is from human waste, since the time spent in the gut exceeds the half-life of caffeine, and when metabolized, its no longer caffeine. There is of course still some small remaining un-metabolized caffeine in urine. A liter of espresso may contain as much as 2254 milligrams of caffeine. But when filtered through a human gut 5 to 10 milligrams/liter in urine is unusual, and 15mg/l gets you bounced from most sports programs as a sign of abuse.

It seems far more likely that the coffee poured out by restaurants, offices, and households, and the disposed of grounds being used for compost and gardening are a larger source than what comes out in the urine stream. Also the water Decaffeination processes is the source of the excess caffeine in city sewage, even though caffeine thus recovered can be marketed into the soft drink business, not all small operations bother with that.

Quoting the first linked source:

Caffeine occurrence and concentrations in seawater did not correspond with pollution threats from population density and point and non-point sources, but did correspond with storm event occurrence.

So it seems to me that the caffeine is just as likely entirely natural, perhaps produced in very low quantities by some naturally occurring plants in the predominantly coniferous temperate rain forests of the area, rather than by any human activity or byproduct. Such a low production would leach out into streams and rivers during storms, but not from municipal sewers, and hence would not correspond to population density.

Re:Metabolites and half lifes

[icebike]

Sorry, wiki only says the bit about:

Caffeine is metabolized in the liver by the cytochrome P450 oxidase enzyme system (to be specific, the 1A2 isozyme) into three metabolic dimethylxanthines. Further, In healthy adults, caffeine's half-life has been measured with a range of results. Some measures get 4.9 hours, and others are at around 6 hours

The rest was my posting error.

Re:Metabolites and half lifes

[Dunbal]

Er you missed the part where caffeine is hydrosoluble. Since Wikipedia is no substitute for say, pharmacology classes in medical school, most of your assertions are irrelevant. While caffeine is metabolized by the liver like almost everything else: all small, hydrosoluble molecules are filtered out at the glomerulus and form part of the ultrafiltrate. Water soluble molecules are then not re-absorbed. Therefore while caffeine is metabolized in the liver, it and its metabolites are excreted via the urine. How much caffeine is metabolized and how much is excreted "as is" depends very much on dose, the patient's ability to metabolize it, and any exogenous factors (medication, etc) that could affect the rate at which the liver can break it down.

The liver takes time to metabolize things and like any enzyme dependent process, it can be saturated. The filtration from the kidney however is a physical process. So long as blood flows through it that has caffeine in it, some of that caffeine is going to get filtered out. And because the kidney is pretty good at keeping water-soluble molecules out (you know, things like urea), once it's filtered it stays filtered. Lipid soluble molecules can always find a way to sneak back in on their own, but the other stuff (like say, glucose) ain't getting back in unless there's an active transport system to pull it back in.

Re:Metabolites and half lifes

[Dunbal]

ALL glucose is filtered out by the kidneys. 100% of it. It is then reabsorbed via active transport (actually sodium-glucose cotransport). The reason diabetics urinate glucose is because their blood glucose levels are so high, leading to such a high concentration of glucose in urine, that this saturates the active transport mechanisms. That is why you automatically know that a patient with any glucose in the urine at all has at LEAST a 180mg/dL blood glucose level, as that's the saturation point of the enzyme based transport mechanism.

Very important to remember in biochemistry that you are dealing with living, falliable systems. There are not many concrete reactions like in a test tube since there are so many variables, and also almost all reactions are subject to having their rate limited by enzyme saturation at one point or another.

Re:Amounts

[Namarrgon]

By comparison, an average cup of coffee contains roughly 100mg, or a concentration of 400,000,000 ng/L.

Fish are much more sensitive to some things

[billstewart]

There are chemicals that can kill fish at 3 parts per billion. There are other things like salt that don't bother them as much, but it's really variable.

However, as other people have pointed out, there are lots of other chemicals getting dumped into the water system, including things like cocaine and prozac that have been processed through humans first. With caffeine, humans metabolize it so you wouldn't get much left, but there's all the caffeine in coffee grounds and waste coffee and soda.

And it is Portland.

Re:Amounts

[jkflying]

The paper lists the North Sea as having between 2 and 16 ng/L. Mediterranean was below 5, Hawaii below 10. Guanabara Bay (Rio) was between 137 and 147. Halifax, Pictou, and Cocagne watersheds (Canada) was between 0 and 1400. Jamaica Bay, NY ranged from 0 - 5000 ng/L. So this is actually pretty low compared to what has been measured in other places, but obviously higher than than plain, untouched seawater.

Re:Amounts

[jkflying]

Hey, I'm just quoting the paper. These amounts are referenced from other papers, which may have been using different techniques for measuring the concentrations.
Here's the North Sea one: http://www.sciencedirect.com/science/article/pii/S0021967301005295
Here's the Mediterranean: http://pubs.acs.org/doi/abs/10.1021/es020125z
Here's Hawaii: http://www.sciencedirect.com/science/article/pii/S0025326X10001839

Re:Amounts

[jkflying]

Sorry, there were 2 North Sea references from the same research group, that was the earlier one, here is the later one:
http://www.sciencedirect.com/science/article/pii/S0048969702000645

Re:How come the water don't smell like coffee?

[TheRaven64]

Tea contains tanin, which blocks the absorption of caffeine. This typically means that you get an immediate caffeine kick from coffee, which then wears off, while tea gives you a slower release of a smaller amount over a period of a few hours. Add to that, after regular consumption you build up a tolerance for caffeine and so won't experience any effects (other than withdrawal if you stop having any), but if you regularly drink tea then you won't be used to the sudden jump in caffeine levels. Oh, and much of the effect of caffeine is psychological. A study a few years ago found that people who unknowingly drink decaf also exhibit the symptoms that they expect from coffee, right up until the point that withdrawal kicks in (and, in some people, the withdrawal is so mild that they don't notice).

Re:How come the water don't smell like coffee?

[Anonymous Coward]

Headache/bad headache != migraine headache. I wish people would really stop saying they get migraine headaches all the time. A migraine head ache is one that is at least 3 days long. Unless your headache was at least that long, it was not a migraine. Also usually migraine sufferers have other issues like not seeing too well, super sensitivity to light, sound, or smell. Could be taste but I never met anyone who had that. They also can vomit or have diarrhea or both at the same time from a migraine. I watched a family member have migraines for years. The many trips to the hospital, and that little pill that messed her up as much as the migraine. When you have a headache where the world is vibrating due to your eye sight being affected from the headache for 3-4 weeks, we'll talk. The one day migraine is BS. That is a headache, not a migraine headache.

Caffeine increases the blood flow. Increase blood flow helps with regular headaches. Not migraines. The doctors had me pumped full of caffeine during one test. I was talking 2-3 times as fast. That tape was funny. Did nothing for the headache I had at the time. For other headaches, caffeine works well. Why do you think Excedrin works well for regular headaches.

Another observation: If you actually do get migraines often, see if something near the head or neck is out of alignment or pinched. Most of the heavy migraine sufferers I know had a pinched nerve, out of alignment neck or jaw. Getting those fixed helped slow the frequency of migraines dramatically. Mine issue was my jaw. A tooth came in that hit my lower jaw. That made my jaw not line up correctly. It was off by just a little. Had the tooth taken out. Now I have a few headaches a year instead of a few weeks of no headaches a year.