July 31, 2013

Roman Bioarchaeology Carnival XXXI

All your Roman bioarch news for the month of July, with quite a lot of finds coming from England this month...

Finds and Features

Shrine burial from Rutland, England (BBC)
  • July - CSI: Italian Renaissance (Smithsonian Magazine). This article profiles the work of Gino Fornaciari.  His work is largely on Medieval Italian remains, but the entire article is worth a read.  His findings over the years are truly amazing!
Skeleton from Gloucester (BBC)
  • 31 July - Roman Skeletons Discovered in Gloucester (BBC News). Not much in the way of reporting on this one yet; hopefully we'll get more details soon, as this cemetery found outside of Gloucester is being heralded as "one of the most significant finds in the city in the past 30 years." It's unclear how many skeletons have been recovered (in addition to the 40 or so found decades ago) and how many have yet to be excavated.
Follow-Ups
Articles
Day of Archaeology
  • 26 July - This year's Day of Archaeology has a number of entries tagged with Roman and/or Osteology, so click through and check them all out while you're waiting for next month's Roman Bioarch Carnival!

July 24, 2013

3D Printing is as bad as... Using an electric frying pan.

We're still working on 3D printing here, a grad student and I, and I'm still very pregnant, so today's story from Gizmodo oh-so-helpfully freaked the hell out of me and likely all 3D printing hypochondriacs around the world: "3D Printing Indoors Is as Bad For You as Smoking a Cigarette Inside".  If anything will get me to read a scientific article about atmospheric pollution, that title will.

I followed the links in the Gizmodo story to Phys.org's article, "3D Printers Shown to Emit Potentially Harmful Nanosized Particles."  This is not my favorite site for scientific news, as it's often full of press releases disguised as reporting and poorly-reported scientific articles.   So, after reading at Phys.org that "The emission rates were similar to those measured in previous studies of several other devices and indoor activities, including cooking on a gas or electric stove, burning scented candles, operating laser printers, or even burning a cigarette," I had to go read the scientific article.

In the study, accepted for publication in the journal Atmospheric Environment, Stephens, Azimi, El Orch, and Ramos studied the concentrations of ultra-fine particles (UFPs) in a 45 cubic meter office with a combination of five 3D printers variously running and variously printing in ABS and PLA (the two major types of plastic filament on the market).  They measured the UFPs in the room at baseline/period 1 (with printers off overnight), period 2 (two printers running for 20 minutes using PLA), period 3 (2 printers with PLA and three with ABS, each running for 20 minutes), and then once they turned the printers off (period 4). The authors admit that their study design is not perfect: after all, there's no real way to compare the differential effects of printing with PLA versus ABS.  And they don't note which brand(s) of 3D printers were used.

Figure 2 from Stephens et al. (in press)
Anyway, the results are interesting.  Figure 2 from the article shows a massive spike in the concentration of UFPs when the five printers were running.  (However, they did start from a higher baseline than zero.)  Considering they simply added three printers with ABS in this period, it would seem that ABS -- which has to be printed at higher temperatures and is known to be toxic, whereas PLA is biocompatible and made largely of corn -- is a major problem in 3D printing indoors.  UFPs, the authors note, "deposit efficiently in both the pulmonary and alveolar regions of the lung, as well as in head airways" and are "associated with adverse health effects, including total and cardio-respiratory mortality."

So UFPs are bad.  But what about the concentration of them in a standard-size office?  Well, Stephens and colleagues write that:
Several recent studies have also reported size-resolved and/or total UFP emission rates from a variety of other consumer devices, appliances, and activities such as laser printers, candles, cigarettes, irons, radiators, and cooking on gas and electric stoves.
Now go back and read what Phys.org editorialized -- that the authors were directly comparing the UFP concentration they measured to all of these things unfavorably.  But they didn't do anything of the sort.  They go on in the very next sentence to write that (emphasis mine):
Unfortunately, it is not straightforward to compare our results directly to results from many of these studies because they have varied in both their minimum and maximum measured particle sizes, as well as in their definition of UFPs. However, Buonanno et al. (2009) reported total UFP emission rates over the same size range as ours measured during various cooking activities. For comparison, our estimate of the total UFP emission rate for a single PLA-based 3D printer (1.9-2.0×1010 #/min) was similar to that reported during cooking with an electric frying pan (1.1-2.7×1010 #/min). The same 3D printer utilizing a higher temperature ABS feedstock had an emission rate estimate (1.8-2.0×1011 #/min) similar to that reported during grilling food on gas or electric stoves at low power (1.2-2.9×1011 #/min), but approximately an order of magnitude lower than gas or electric stoves operating at high power (1.2-3.4×1012 #/min).
Alrighty, then.  Phys.org wildly misinterpreted fairly straightforward prose, and Gizmodo picked it up without checking the original source article.

This post isn't to say that 3D printing is superduper awesome for your health.  There are clearly very few studies that have actually attempted to measure this outcome, in spite of the boom in 3D printing in the last year or so.  The authors rightly conclude: 
...both [PLA and ABS] can be characterized as “high emitters” of total UFPs. These results suggests [sic] caution should be used when operating some commercially available 3D printers in unvented or inadequately filtered indoor environments. Additionally, more controlled experiments should be conducted to more fundamentally evaluate aerosol emissions from a wider arrange [sic] of desktop 3D printers and feedstocks.
Unfortunately, this doesn't answer my question, which is... Am I harming myself or my unborn baby by running one or two MakerBots in my office?  I could probably run a printer in the fume hood in the forensic anthropology lab to be extra safe, and I'll likely cut way back on my 3D printing until after the baby's born.  But considering I wasn't printing a whole lot to begin with -- thanks, MakerBot, for making 3D printing rather difficult! -- and knowing how little time I've run each of the printers in the last year, it doesn't seem to be a high risk to my health or to the baby's.  Something to think about, though, if you are into or want to get into 3D printing.

Reference:

B. Stephens, P. Azimi, Z. El Orch, T. Ramos (2013). Ultrafine Particle Emissions from Desktop 3D Printers Atmospheric Environment DOI: 10.1016/j.atmosenv.2013.06.050.

July 1, 2013

Roman Bioarchaeology Carnival 30

Oddly, not a lot happened this month in the world of Roman bioarchaeology.  Maybe everyone's gearing up to find or report on new things in July and August.  (There was a ton of Medieval cemetery news this month; wonder if that's the next big frontier in bioarchaeology?)

News and Finds
  • 12 June.  Iron Age tombs in Serbia were discovered during construction.  A bit outside the purview of Roman bioarch, but interesting nonetheless.
    Iron Age tomb from Serbia (credit)
  • 16 June.  A Roman tombstone from Oxfordshire (England) is going on display.  It dates to 79 AD and records the passing of an Italian-born soldier Lucius Valerius Geminus.
79 AD tombstone from Oxfordshire (credit)
  • 28 June. Evidence of 2000-year-old Famine Found in Jerusalem. (Discovery News)  Archaeologists think that three cooking pots and an oil lamp are evidence of food that was squirreled away by Jewish residents of Jerusalem during its siege by the Romans around 66 AD.  I wonder if there's any osteological evidence of the famine from skeletons in the area?
  • 28 June. Skeleton family set for field reburial. (Daventry Express)  Six skeletons (female, three males, an adolescent, and an infant) were found during routine excavations in 2004 in Nether Heyford (Northamptonshire, UK).  They apparently date to the 5th-6th centuries, which is a just post-Roman time period without a lot of skeletal evidence in England.  Archaeologists think the "family" might have been of foreign origin; they are keeping teeth for future DNA work, but the remainder of the skeletons will be reburied this week.
  • 27 June. In search of the lost city (El Pais). A Visigothic cemetery outside of Madrid (c. 5th-8th centuries AD, so just post-Roman) is apparently slated for destruction because it has "no significance."  Archaeologists, however, want more time to look for the settlement that they assume is associated with this large (c. 1,500 burials!) cemetery.
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