"Hair" Pollution: How what you eat and breathe affects the composition of hair
Sarah - We're going to do the whole of the hair, rather than sections of the hair, so I'll take it at the bottom of your head. I'll try and cut it in the same region so you're not left with too many spikes.
Azi - I've come to Anglia Ruskin University at the Department of Forensic Science and Chemistry, and I'm joined by Dr Sarah Hall, who's a specialist in looking at heavy metal concentrations in hair.
Sarah - I think that'll do. And there we go. OK?
Azi - Oh, right. So you've got a good lump of my hair. Fantastic!
Sarah - It's a fair amount. Sorry!
Azi - No, no, it's fine.
Sarah - OK. Now I'll do mine. I think that'll do. There we go.
Azi - Where would contamination of heavy metals come from?
Sarah - Well it would come from a number of exposures - atmospheric exposure, maybe from your food, your drinking water - but all hopefully low levels.
Azi - Now, it's quite interesting with me, because I've only actually lived in Cambridge for the past three months, and before that I was living in London.
Sarah - I live in Ely [Cambridgeshire, UK], and I've lived in Ely for ten years, and hopefully we may see a difference between yourself and me living in Ely.
Azi - What sort of things would you expect to be exposed to in Ely?
Sarah - Traditionally, you'd think that there may be some exposure from farming practices, maybe herbicides. Traditionally, arsenic tended to be used in herbicides. But again legislation, and changes in farming practices, mean that we may not see that, but we may see a difference because you lived in a more built-up area.
Azi - Fantastic! Well that sounds really exciting. I was also wondering whether you'd be able to tell the difference between somebody's diet, for example, because I don't eat meat at all. I don't even eat fish! But would my hair show up things that, perhaps, somebody who has a different diet practice would not show up, or the other way around?
Sarah - Actually, I've got a research student who I know is a meat-eater. Let's see if we can talk her into taking a bit of hair.
Azi - Could we, please?
Sarah - Yes.
Azi - Excellent.
. . .
Azi - OK, so now that we've got three bits of hair - one from you, one from me and one from Lata - what are we going to do with them then?
Sarah - Well, first I think we should wash them in a soap solution, just basically to remove any sort of conditioner or any hair product. I'm just going to give these a little stir, and then we're going to put them in the sonicator.
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Sarah - All I'm going to do now is just decant the soap solution off, and then wash the hair with some de-ionised water, then a last wash with some methanol, dry it in a bit of filter paper, and then we should be able to easily cut it into smaller sections and get it into our containers.
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Sarah - I've got your hair in the container now, so I'm just going to add nitric acid and hydrogen peroxide, and then pop it in the oven, as they say. And that's it - just leave them for about four hours to digest. Once they've digested, you've got your metals into solution, which then allows us to do the analysis.
Azi - Lovely. Alright, well, what I'll do is, while we wait for everything to cook, I'll pop across the corridor and have a chat with Dr Karen Scott.
Sarah - Yes, okay. And I'll see you soon.
Azi - Yep, excellent. I'll see you in a bit then.
. . .
Karen - Hi, I'm Dr Karen Scott. I work in the Department of Forensic Science and Chemistry at Anglia Ruskin University, and I'm a Forensic Toxicologist.
Azi - So, you look at all the components that get into people's hair, but how do they actually get there to start with?
Karen - Well, basically, anything that is ingested into your body goes into your bloodstream, and our hair grows from components which are retrieved from the bloodstream. As the hair then grows out of the head, the drugs and other substances bind to melanin within your hair, so something that was there, say, a month ago, a month later will be one centimetre away from the point of start of growth of the hair.
Azi - What can hair tell you about a person?
Karen - It can tell you ethnicity. It can tell you which part of the body it's been taken from. It can't tell you whether the donor is male or female, unless you go down the DNA route. It can give you an indication, obviously, if they've dyed or treated their hair in any way. And also, it can tell us if they've ingested drugs in the past. So there are lots of different things that we can tell from the hair sample.
Azi - Dr. Sarah Hall is actually showing me how she can get heavy-metal exposures from hair samples.
Karen - Yes, so that will give you an idea of things like diet. Most people, when they think of forensics, are thinking of crimes being committed - maybe somebody's been poisoned, or someone's been taking drugs - but we can also look at environmental effects in terms of exposure to chemicals which we shouldn't be exposed to.
Azi - Thank you very much. It's been a pleasure.
. . .
Azi - Well, Dr. Hall, you've been looking at these samples and you've got the analysis, so can we have a look and see what you've got?
Sarah - I have to say, we have no cadmium or lead, but Lata had quite an unusual high concentration of nickel. However, she does tell me that her diet is based on a lot of pulses and lentils, and nickel is found in that sort of food.
Azi - But was there anything to differentiate her meat-eating diet with our vegetarian diet?
Sarah - Well, I tried to look at that, so I was looking at iron - because I thought it would be rich in meat and liver - and zinc is quite a lot found in meat, shellfish, dairy foods and cereals. But it doesn't really show in the results much difference between the meat-eaters and vegetarians, I'm afraid.
Azi - So what about the phosphates? Did we find anything that was different between the three of us that perhaps indicated the levels that you might be exposed to in Ely?
Sarah - No. Actually, I had a lower phosphate level than Lata and yourself. In fact, Lata had a higher phosphorus level than both of us, but it might be because of the diet, because there's a fair amount of phosphorus in red meat and fish. So, that might be the difference between the vegetarian and meat-eaters.
Azi - What else has been interesting?
Sarah - The only thing there was an increase on was copper, and, again, Lata had a higher copper level than we had. Copper is found in shellfish and offal. Lata tells me she doesn't eat too much shellfish, but I think she eats a fair amount of red meat, and maybe offal.
Azi - I think you mentioned that Lata has an Asian background. Is that right?
Sarah - That's correct, yes.
Azi - And I know that some Asian families use copper to serve food on or even to cook food in. Would that have something to do with it?
Sarah - Ah, yes. Well, it could do, because a lot of lead pollution years ago came from cooking implements and drinking vessels that were actually made of lead compounds. So yes, that could be true.
Azi - Excellent. Well, thank you very much. It's been absolutely fascinating, and I'm really thrilled that I'm quite healthy and I can carry on with my healthy vegetarian diet. Thank you.