Oct., 1920
T H E J0UR;C’AL O F I N D U S T R I A L A N D E N G I N E E R I i Y G C H E M I S T R Y
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I O O per cent as could be expected with methods of this stances present in oak wood: t h e pentosans soluble in character. cold, dilute, sodium hydroxide solution, t h e furfural( 2 ) As compared with other procedures tried, yielding constituent of t h e cellulose, and t h e commaximum yields of cellulose and lignin are obtained, paratively small amount of pentosan, resistant t o t h e with a minimum of impurities or degradation products. alkali treatment b u t dissolved during chlorination. It would appear t h a t t h e first of these is wood g u m (3) Overlapping of constituents is avoided. The (xylan or araban), and t h e second oxycellulose. T h e cellulose was found free from lignin. T h e studies of Konig and Becker have shown t h a t t h e gaseous hydro- last may be due t o more resistant pentosan or t o chloric acid method gives a cellulose-free lignin. T h e pectin. T h e simultaneous presence of galactan and galactan is determined by a method t o o specific t o methoxy groups not due t o lignin suggests t h e latter. T h e present investigation indicates t h a t alkaline include either of these constituents. T h e other constituents are determined in separate successive extrac- digestion is necessary for t h e best results with oak wood, tions and cannot therefore overlap with t h e above and presumably with t h e hardwoods generally. From t h e work done so far, it would appear t h a t t h e conif“residue constituents.” erous woods should be prepared without, and t h e (4) N o substances of importance have been overlooked. I n addition t o constituents specifically named hardwoods with, alkaline digestion. Further work is in:the analysis, woods are known t o contain in greater necessary t o determine whether this rule is generally or less amount: acetic-yielding groups, furfural- applicable. It appears probable t h a t t h e method of yielding groups (pentosans, etc.), methoxy groups, alkaline digestion will be found effective with all cutin, pectin, nitrogenous substances, and ash. A highly colored woods. S U NMlA R Y brief consideration of t h e available d a t a will show t h a t these substances are largely accounted for in t h e I-Methods previously used for t h e analysis of fractions deter mined. coniferous woods were investigated as t o their appliIt has been shown t h a t t h e groups yielding acetic cability t o t h e hardwoods. Oak wood, as a typical acid on hydrolysis are wholly contained in t h e extracts hardwood, was analyzed by suitable modifications of removed i n purifying t h e wood tissue. A study of t h e these methods. with t h e results herein presented. furfural distribution shows t h a t t h e pentosans are fully a-The purification treatment employed for t h e accounted for, partly in t h e alkali-soluble portion a n d tissue of coniferous woods (successive extraction with partly i n t h e chlorination filtrates and washings. benzene and alcohol) was supplemented with digestion T h e balance of t h e furfural yield is from t h e cellulose. in cold water and cold j per cent sodium hydroxide The methoxy distribution shows t h a t these groups are solution. These treatments remove all adventitious largely associated with t h e lignin. Most of t h e substances, b u t do not injure either t h e cellulose or t h e methoxy groups t h a t are not so associated are accounted lignin. for in t h e water- and alkali-soluble portions. A small 3-Lignin was determined by t h e gaseous hydroamount (0.8 per cent), however, is apparently split off chloric acid method recently proposed by Konig and during t h e hydrochloric acid treatment, and this portion is unaccounted for in t h e s u m of constituents. Cutin B ecker. 4-The modified procedure conforms t o t h e requireis absent, as shown by t h e complete solubility of t h e cellulose residue i n 7 2 per cent sulfuric acid. Precise ments of a satisfactory analytical scheme in t h a t i t accounts for all of t h e material of t h e wood, yields t h e information is lacking as t o t h e chemical nature of pectins and their occurrence in woods. I t is known maximum amount of main constituents free from imt h a t pectin contains methoxy, and yields furfural on purities or degradation products, avoids overlapping distillation with hydrochloric acid and mucic acid on of constituents, and overlooks no constituents of imevaporation with nitric acid. T h e presence of galactan, portance. pentosan, and non-lignin methoxy groups in t h e residutl may be taken as a possible indication of pectin. NITRATE CONTENT OF CERTAIN WATERS CONSIDERED If so, i t is largely accounted for i n its above-mentioned BACTERIOLOGICALLY SAFE’ decomposition products. By M. Starr Nichols T h e purified wood tissue after successive treatments WISCOXSINS T A T E LABORATORY O F HYGIENE, U N I V E R S I T Y O F &’ISCONSIX, with t h e four solvents contains only a few t e n t h s of MADISON, WISCOXSIN a per cent of nitrogen and a similar amount of ash. The quantity of nitrate nitrogen permissible in a Presumably these small quantities are distributed potable water has been t h e subject’ of much consideraover t h e constituents cellulose and lignin. S o con- tion and speculation. While every sanitarian has his siderable error can result from neglecting t h e m alto- own quantity standard upon which he bases his judggether ment as t o t h e source and quality of a given water, As has already been noted, t h e composition of t h e each agrees t h a t a large amount of nitrate nitrogen various extracts has not been fully worked out. I n cannot be disregarded. Richards and Woodman2 say, their aggregate, t h e amount of these extracts measures “ I n eastern America nitrates above 0 . j p a r t per million t h e t o t a l amount of adventitious substances, as dis- wouldarouse suspicion, and above j parts per million tinguished from t h e wood substance proper. 1 Presented at the 59th Meeting of the American Chemical Society The distribution of furfural-yielding groups shows St Louis, Mo , April 12 t o 16, 1920. 2 “Treatise on Air, Water, and Food,” 3rd E d , 1811, p 92. t h a t there are probably three forms of these sub-
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T H E J O C R h r A L O F I N D C S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y 1701.
would in most cases prove previous pollution.” Booth’ concludes from his investigation t h a t , “if nitrates are present in water above one part per million, i t may have a n unwholesome source.’’ Stoddart,2 in an article published in 1893 on t h e interpretation of water analyses, maintains “ t h a t natural waters can, a t most, contain b u t from 0.1 t o 0.2 grain of nitrogen per imperial gallon” (approximately 1.4t o 2 . 8 parts per million) “from sources other t h a n animal matter.” Quoting from Ridea13 we find, “Therefore a water which contains over 0.j t o 0.6 part of nitrogen, as nitrates or nitrites i n I O O . O O O , may be certified as dangerous.” On t h e other hand. Kuh14 contradicts these opinions, after working with certain types of denitrifying organisms, by saying, “The presence of nitrates in water is not a n indication of contamination.” DETAILS O F PROCEDURE
The present paper is a report of t h e nitrate-nitrogen findings of 808 (Wisconsin) waters which were found t o be safe bacteriologically. The bacteriological standards were those adopted by t h e Treasury Department of t h e Upited States for drinking water supplied t o t h e public by common carriers i n interstate commerce. The samples were collected in sterilized glass-stoppered bottles from deep wells, shallow wells, springs, and rivers; iced; and shipped t o t h e laboratory in special containers. Drilled wells were arbitrarily considered deep, while those dug and driven were classified as shallow. A sanitary survey of t h e source of t h e water was not made in any regular manner, and only fragmentary d a t a given by t h e local health officer who collected t h e sample were available for comparison. K O correlation of these d a t a with t h e analytical results has been attempted. The nitrate nitrogen was determined by t h e phenoldisulfonic acid method of t h e American Public Health Association,6 using jo cc. of t h e samplp for a determination. A complete list of analyses will not be included in this paper, b u t only such groupings as will give a fair idea of t h e quantities
present.
TABLE I
Well water Spring Fresh pond Driven well Deep well Deep well New wells Well Well Artesian well Spring
NITROGEN AS NITRATES P. p. m. INVESTIGATOR LOCATION Mason Adirondack Mts. 0.28 0 . 0 8 t o Fuller Croton, N. Y.
0 209 Hyde Park, Mass 0 532 Arlington, Mass. 1 25 Cambridge, Mass. 0.3 South Carolina 0 6 Texas 0.0 Lake Winnipeg 1 6 Lyon, N. Y 0.1 Norwich, England 8 0 Alexandria Va 0 3 Rocky Forh, Col 0 13 Wehster Grove, M o . 4 . 0
Mass. State Board of Health Mass. State Board of Health Mass. State Board of Health Richards and Woodman Richards and Woodman Richards and Woodman Booth Thresh Clarke Hillebrand Hillebrand and Howard
“Water Analysis and the Nitrogen Content of Water,” J. A m . Water W o i k s A a s o c , 2! (1915), 61. 2 A n a l y s t , 18 (1893), 293. “Water and Its Purification,“ 2nd Ed., 190%,p. 202. “The Reduction of Nitrates by Denitrifying Bacteria and Its Importance in the Judgment of Waters.” 6 “Standard Methods of Water Analysis,” 1917. 3
4
NO.I O
I n Table I1 are given t h e total results of analyses of 808 waters irrespective of source. TABLE I1 Nitrate Nitrogen P. p. m . 0.00- 1 . 0 1.01- 5 . 0 5.01-10.0 10.01-20.0 20.01-30.0 30.01-40.0 40.01-50.0 50.01-60.0
Number of Waters 475
Percentage 58.8 23.9 12.5 4.4 0.1 0.1 0.1 0.1
193 101 35 1
1 1 1
From these results i t is seen t h a t a water may be entirely safe bacteriologically and yet have exceedingly high nitrates. I n f a c t in each of 140 of these waters there is enough nitrate nitrogen t o prove previous pollution, according t o t h e standard of one author quoted. Bacteriological examinations tell us nothing, therefore, of t h e past history of a bacteriologically safe water, nor do they tell us anything of any-potential danger. I n other words, a bacteriological examination can a t most tell us only whether t h e water sample a t hand does or does not exceed t h e standard in number of certain counts and types of organisms. I n Table 111 t h e analyses are grouped t o show the nitrate-nitrogen findings as related t o the source of t h e supply. Nitrate Nitrogen P. p. m. 0.00- 1 . 0 1.01- 5.0
TABLEI11 ( 7 1 Waters) SPRINGS Number of Waters ’ 35 20
5.01-10.0
13
10.01-20.0
3
20.01-
0
Percentage 49.0 28.0
19.0 4.0 0.0
SHALLOW WELLS (250 Waters) 0.00- 1.0 1.01- 5 . 0 5.01-10.0 10.01-20.0 20.01-30.0 30.01-40.0 40.01-50.0 50.01-60.0
0.00- 1.0 1.01- 5 . 0 5.01-10.0 10.01 20.0
20.01-30.0 30.01-40.0
50.0 24.0 18.0 6.8 0.4 0.0
1 24 60 46 17
1 0 1
0.4 0.4
1
DBEP WELLS(446 Waters) 277 111 42
62.1 24.9
9.4
15 00 1
3.4 0.0 0.2
LAKES(28 Waters
I n order t o compare t h e results of these analyses with analyses of normal waters given by other investigators, a compilation of their respective results is given in Table I.
SOURCE Spring Watershed
12,
0.00-0.1 0.11-0.5 0.51-1.0 1.01-2 .o
15
52.0 40.0 4.0 4.0
11 1 1
RIVERS(13 Waters) 7 5 0 1
54.0 38.0 0.0 8.0
It is t o be seen t h a t low values for nitrate nitrogen, up t o j parts per million, are found in 87 per cent of t h e deep well waters, while even t h e shallow wells and springs show a similar low figure for nitrate nitrogen, in 74 and 7 7 per cent, respectively. I n t h e results for lakes and rivers no high values for nitrate nitrogen are found. SOURCES OF NITRATE NITROGEN
A question naturally arises as t o t h e source of this large amountof nitrogen which is present as nitrate in some ground waters. If it is derived from unpolluted soil leachings, from niter beds, or from nitrogen carried down from t h e atmosphere by rain as nitrates, we should not be a t all concerned. The Rivers Pol-
Oct.,
1920
T H E J O - U R N AL O F I i Y D U S T R I A L A N D E N G I N E E R I - V G C H E M I S T R Y
lutiori Commission,1 after examination of a large number of samples of rain water, found t h e mean amount t o equal 0 . 3 2 p. p. m. nitrate nitrogen. Galez says t h a t no extensive beds of nitrates are t o be found in t h e United States, b u t t h a t small deposits occur in many places throughout t h e country, especially in certain caves. Nitrogen as nitrate occurs in t h e soil in varying quantities, depending upon t h e nature of t h e soil, as well as on t h e time of year, kind of crop, a n d amount of cultivation. I n general, soil contains from 5 t o 2 0 0 p . p. m. of nitrate nitrogen, though Headdon3 found as high as 60,000 p. p. m. in certain brown spots in Colorado soil. N o such soil has been found, t o t h e author’s knowledge, in any other locality in t h e United States. T h a t t h e amount of nitrates varies with t h e depth a t which t h e sample is taken is illustrated by t h e work of King and Whitson,‘ who found t h a t soil under clover and oats showed, in p. p. m. of t h e dry soil, 23.39, 18.33, 9 . 4 7 , and 7.9 for the first, second, third, and fourth foot of soil, respectively. T h a t manure piles, cesspools, cesspits, privies, sewage, and in fact any decaying animal matter .may yield enormous amounts of nitrogen as nitrates is a wellknown fact hardly necessary t o repeat. T h a t ground waters receive large amounts of nitrate nitrogen from t h e soil is not borne out by t h e work of Malpeaux and Lefort’j who found t h a t nitrates plowed t o a depth of I O in. appeared a t t h e end of 11 days in t h e top 3 in., and those plowed t o a depth of 2 0 in. reappeared in one month in t h e top 3 in. They finally con.cluded “ t h a t t h e summer rains never carry t h e nitrates beyond t h e reach of t h e roots of plants.’: Aladjem6 concludes t h a t “in waterlogged soils,” a condition obtaining in many water-bearing strata, “nitrates are decomposed.’’ Ritter7 states t h a t nitrates are reduced by t h e nascent hydrogen formed in the decomposition of peat. Tkachenkos remarks t h a t there was “little leaching of nitrates during t h e rainy periods, and this was not noticeable in any case below 2 5 t o jo cm.” Mendelejeffg gives his opinion t h a t nitric nitrogen loses its oxygen on penetrating into t h e earth. A careful study of wells10 in t h e immediate locality in which Dr. Headden reported 60,000 p. p. m. nitrate nitrogen in t h e soil, previous t o t h e appearance of the niter trouble, failed t o disclose more t h a n a trace of nitrates. T h a t surface waters do not abstract much nitrate from t h e soil is shown by t h e invariably low nitrate content of rivers and lakes a t all seasons of the year. However, by allowing rain water t o drain down through z f t . layers of soil samples contained in John C . Thresh, “Water Supplies,” 2nd E d . , p. 166. U. S. Geological Survey, Bulletin 666-2. 3 Colorado Agricultural Experiment Station, Bulletin 186 (1913). 4 Wisconsin Agricultural Experiment Station, Bullelin 93. 6 “The Circulation of Nitrate in Soils,’’ A n n . Sci. Agvmz., 30 (2). 705. “Production of Alkali in Soils b y Denitrification,” Cairo Sci. J . , 8, 274; through Chem. Abs., 10 (1916), 3128. 7 “Peculiarities o f Nitrate Formation and the Nitrate Content of Moor Soils,” Intern. Mitt. Bodenk., 2 , 411; through Chem. A b s . . 8 (1914). 1180. 8 “Observation on the Formacion and Layer Distribution of Nitrates in Soils, with Different Nitrogen Fertilizers,” Khoziaistvo, 37-40 (1912); Zhuv. O i N u . .4gvon., 14 (1913), 585; Expt. Sta. Recovd, 33 (1915), 422. 8 “Chemistry,” p . 223. l o Walter G. Sackett, “The Nitrifying Efficiency of Certain Colorado Soils,” Colorado Agricultural Experiment Station, Bdleliiz 193, 5 . 1
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percolating pots, Frapsl obtained I I t o 2 0 0 p. p. m. of nitrate nitrogen. It seems possible, therefore, t h a t if a fissure should form in t h e subsoil a t a depth of 2 o r 3 ft., a ground water might be obtained which contained a large amount of nitrates derived from t h e surface soil. I n any event. t h e water so obtained could not be considered safe. I n this connection Stoddart2 describes an experiment in which sewage containing cholera spirilla was passed through a nitrifying bed of coarsely powdered chalk, with t h e result t h a t although t h e organic matter in solution was completely nitrified, the cholera spirilla could be detected in t h e effluent. T h a t t h e character of t h e soil does not have much effect upon t h e quantity of nitrate nitrogen in t h e ground water is indicated b y t h e fact t h a t ground waters in every locality of t h e state, representing soil ranging from the sand and gravel types t o t h e heavy black soil of the marshes, are found with less than I p. p. m . I n more t h a n 7 j per cent of t h e counties t h e low figure for nitrate nitrogen is below 0.1 p. p. m. These facts also oppose t h e theory t h a t there a t e mineral deposits of nitrates from which t h e nitrate nitrogen is derived. The work of W i l l i ~ confirmed ,~ by t h e following example, shows t h a t a well may be potentially dangerous, although safe bacteriologically: Dug well, in basement of a hotel in a small Wisconsin village, protected from surface washings, b u t subject t o possible pollution from outhouses; soil, sandy loam. T h e bacteriological examination showed no B. coli, only 4 bacteria growing at 37O C., and only 13 growing a t 2 0 ° C., but t h e nitrate nitrogen was 60 p. p. m. Judged bacteriologically, this is a n entirely safe water, yet there are few sanitarians who would not condemn t h e supply on t h e nitrate findings. CONCLUSIONS I - h excessive quantity of nitrate nitrogen is not a normal component of safe ground waters. 2-Many difficulties must be surmounted before i t will become possible t o set an accurate standard, b u t from t h e results here presented and from t h e evidence contained in t h e literature, a water containing j or more p. p. m. of nitrate nitrogen should be considered as a potentially dangerous supply until a sanitary survey can be made b y a competent person. 3-The nitrate-nitrogen determination should be included in every ground-water examination. I
RELATIONSHIP OF HYDROGEN-ION CONCENTRATION OF NATURAL WATERS TO CARBON DIOXIDE CONTENT4 By R. E. Greenfield and G. C. Baker STATE W A T E R S U R V E Y DIVISION,U R B A N A > ILLINOIS
The effect of hydrogen-ion concentration upon biological processes has recently been much studied b y biologists. The results indicate t h a t i t is more of a governing factor t h a n is t h e total acid or alkali content. Texas Agricultural Experiment Station, Bullelin 171 (1914), 5. John C . Thresh, “Water Supplies,” 2nd E d . , p. 167. 8 “Value of Nitrate Figure in Determining Fitness of Water for Drinking Purposes,” J . Proc. R o y . SOC.N e w S . W a l e s , 46, 408. 4 Presented a t the 59th Meeting of the American Chemical Society, St. Louis, M o . , April 12 t o 16, 1920. 1
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