IIKI’OHT OF CHF,HrlCAL LABOEATOBY 
397 
Poisoxors \Yell Waters 
It is not often that a well water, even though highly contaminated, is found to contain 
sufficient of any single mineral constituent to render it harmful. In Kordofan this 
appears to be not infrequently the case, especially towards the end of the dry season. One 
of these wells, near Nahud, was found to he distinctly poisonous to animals (the water, being 
known to be bad, was only used for animals and washing). A donkey, having drank of the 
water, was seized with severe colic, and died within twelve hours. A sheep was then given 
some of the water and died, suffering from the same symptoms, in an even shorter time. A 
sample of the water was then sent to the Tjaboratories by El Ilimbashi Anderson, S.M.O., 
Kordofan District, with the histoi-y detailed above. On examination the explanation of the 
poisonous character of the water was found to be an exceedingly high proportion of nitrates. 
The quantity of the sample sent was too small to permit of complete analysis, but the 
determinations made were as follows : 
Total solids ... ... ... ... ... 7656-0 parts per million 
Nitrates (NO..,) ... ... ... ... 4428-6 
Chlorides (Cl) ... ... ... ... ... 513-5 
Sulphates (SO^) ... ... ... ... 1298-0 
Carbonates (CO.;) ... ... ... ... 185-0 
Calcium (Ca) ... ... ... ... ... 814-9 
The nitrates are equivalent to 6-5 grammes of nitre 
to the gallon. This is quite sufficient to account for the poisonous effect which was 
observed. 
The smallest lethal dose of potassium nitrate recorded for an adult man is two 
drachms. This would be contained in a little over a quart of the water. 
The water of another well in Kordofan—that near Gebel Schweih- -which in 
Novemher, 1907, contained a proportion of nitrates equivalent to 172 parts of potassium 
nitrate per million, was found in the following May, which is near the end of the dry 
season, to contain as much as 1204 parts per million, a proportion which is probably to be 
regarded as distinctly harmful. 
Limestones and Lime 
per litre, or very nearly an ounce 
Good limestone for lime making is still lacking in many parts of the Sudan. In some 
localities the deposits of root-like masses and nodules are emjrloyed for the purpose, hut 
sometimes with very unsatisfactory results. The attention of those employed in building 
operations should be called to the fact that, as a rule, such lime will give excellent results 
provided it be realised that it is not pure and the mixtures made with it are adjusted 
accordingly j Ac. that they will not permit of the addition of the usual amount of sand 
or Jumira (powdered burned brick). 
On the average these limes contain, after slaking, about 50 per cent, of true slaked 
lime, and rarely as high as 60 per cent. If, therefore, this is allowed for hy a lessened 
addition of sand or hotnra very good results Avill be secured. 
.\n extensive deposit of good crystalline limestone has been found at fehereik, not far 
from Berber and close to the railway, and a special low rate of transport has been granted 
which will permit of its carriage to near-by points. 
.\n analysis of a sample of the deposit gave results as follows: 
Calcium carhonate ... 
Magnesium carhonate 
Ferrous carbonate 
Insoluble in acid (quartz and mica) 
90-02 per cent. 
2-48 
1-70 
6-01 
Total 
Nitrates 
present in 
poisonous 
quantities 
in well water 
Limestones 
and lime 
Good 
crystalline 
deposit 
100-21 
