Not so far as I know, sorry.

Perhaps a portable XRF would do this in the field.

Thanks for your reply Milham Sir and Janhvi Mam.

If you see a silvery tint with the unarmed eyes in your samples known to be from an As-bearing substrate it is not a contamination it is an arsenic ore enriched in arsenopyrite [FeAsS] or in rare cases loellingite [FeAs2] both of which might be in the state of being converted into scorodite [ Fe³⁺[AsO₄]·2H₂O ]. In Bangladesh it will not be the case because the As is accommodated into the lattice of Fe sulfides. It is mostly "invisible" As.

I am really fortunate that Harald G. Dill Sir has participated in this discussion and has given a valuable answer from his experience. I am astonished that he has also knowledge about my country's As problem. Thank you Sir. I wish I could get your email to contact further!!!

I have been working and training young couterpart geologists in Dakkha and in the Chittagong Hill Tracks.

To summarize the situation:

Elevated contents of arsenic in the ground- and surface water in India and Bangladesh are the result of a geogen process caused by oscillating redox conditions in one of the strongest tidal regimes on the globe the impact of which can be recognized for quite a long distance landward of the coastline . The Bay of Bengal ranks besides the Bay of Fundy and Bay of St. Malo among the ultra-high tidal regimes . Arsenic has it primary host in Fe sulfides such as pyrite, marcasite, pyrrhotite, bravoite (Ni pyrite) and greigite. These chemical compounds rank among the most widespread minerals and they are very redox –sensitive. One of the most common oxidic As minerals is scorodite known as a hydrated iron arsenate mineral, with the chemical formula FeAsO4·2H2O. There is no equivalent system for Mn which rarely exists as MnS (alabandine). Moreover in the oxidizing regime bivalent Fe and Mn show strongly different stability fields with FeOOH (goethite, lepidocrocite) being very common and MnOOH (manganite) being rather rare. It goes without saying that dependent upon the redox regime Mn and Fe follow up various pathways of evolution particularly during the supergene alteration under near ambient conditions. And as a consequence of this the chemical relationship of iron and manganese (which has more valence states than iron) breaks apart under oxidizing conditions. Arsenic in the arsenate complex is more common to “limonite” than “manganomelane”. It can be present in a loosely-bound way absorbed to these poorly crystalline compounds of “limonite” or present as a true arsenate. This is not the case with equivalent Mn compounds.

H.G.Dill

Sir, could you please let me know with whom are you working in Bangladesh?Is it Bangladesh Atomic Energy Commission?

Not at all.

Dear Mr. Hossein,

As to your question:

I cooperated with the Geological Survey focusing among others on hydrocarbon exploration.

My part was related to sediment mineralogy and chemistry with a strong point on capturing digital data in the field from PIMA to gamma spectroscopy.

I also worked in uranium exploration.

Maybe you know some of the young colleagues (?) to be seen on the photographs

With kind regards

H.G.Dill

Thank You Sir for you response. You kind words really warmed my hearts. Wishing you a long span of time for the sake of Geoscience!

The answer to the question depends on the location, age, and depth, of the sand you are refering to. In the Bengal Basin, As-pollution of groundwater occurs almost exclusively in the grey sands deposited in the last 18 ka (since the last glacial maximum or LGM for short) and not in deeper pre-LGM sands. The post-LGM grey sands once held iron oxides on which As was sorbed. The oxides have been dissolved and the As released to solution. In the upper 5 to 10 m of the the underlying pre-LGM sands, there is a lot more iron oxide, and little has dissolved, so the As remains sorbed to the oxides and groundwater in such sands is not polluted by As. Deeper pre-LGM sands are grey, but host unpolluted groundwater because all the As they used to contain (on deposition) has been flushed away by > 100 ka of groundwater flow.

So, to return to the question, brown sands have groundwater with < 10 ppb As, shallow (< 150m) grey sands SOMETIMES, not always) have groundwater that is polluted by As. Grey sands > 150m deep (and across many parts of the basin > 50m deep) are not polluted by As.

A better way to assess pollution in an area is to look at the colour of stain on the well, buckets used to transoprt water, or the concrete well-completion. Red stain indicated a possibility of As pollution. Black stain indicates no As, but Mn instead.

Further information on colour as a guide to arsenic pollution can be found in

McArthur J.M., Nath B., Banerjee D.M., Purohit R. and Grassineau N. (2011). Palaeosol control on groundwater flow and pollutant distribution: the example of arsenic. Environ. Sci. Technol., 45, 1376–1383. dx.doi.org/10.1021/es1032376.

The presence of pyrite in the sediments of the Bengal Basin has little to do with the arsenic pollution apart from lessening its severity marginally.

See P. Ravenscroft1,2, J.M. McArthur3* and B.A. Hoque4, 5 (2001). Geochemical and Palaeohydrological Controls on Pollution of Groundwater by Arsenic. In: Arsenic Exposure and Health Effects IV. W.R. Chappell, C.O. Abernathy & R. Calderon (Eds), p 53-78, Elsevier Science Ltd. Oxford.

I recommend the PhD thesis of Mohammed Hossain (see attached). Hossain presented a sediment color chart for easy on-site identification of arsenic in sands.

Hossain, M., 2015. Sustainable Arsenic Mitigation - A strategy developed for scaling-up safe water access. Doctoral thesis in Land and Water Resources Engineering, KTH Stockholm, Sweden.

Thanks a lot Marinus Sir..I am really delighted to get it.