INVESTIGATION AT ANACONDA, MONT. 21 



(2) There can be but little doubt that the injury extends beyond 

 the limits mentioned in the preceding paragraph, but this can not be 

 shown by chemical analysis, since the difference in sulphur trioxid 

 content between injured and uninjured trees becomes so small as to 

 be within the limits of experimental error. 



FIRST INVESTIGATION OF INJURY BY SMELTER WASTES 

 AROUND ANACONDA, MONT., 1906-1907. 



A third extremely important study of injury to vegetation and ani- 

 mal life by smelter wastes was conducted by the writer in the country 

 surrounding Anaconda, Mont., and at Washington during the latter 

 part of 1906 and the whole of 1907. In the immediate vicinity of 

 Anaconda the huge Washoe smelter is situated, roasting, when run- 

 ning at full head, from 8,000 to 10,000 tons of ore per day, which 

 ore is said to contain quite large quantities of arsenic. (See PI. V.) 



The plant is situated in a semiarid country, where irrigation is 

 T)racticed, and discharges its tailings and slags into certain of the 

 streams that are used for irrigation purposes. There are therefore 

 three distinct problems to be worked out in connection with the 

 injury caused by the smelter: 



(1) Whether or not the vegetation is injured by reason of the 

 sulphur dioxid and trioxid set free. 



(2) Whether enough arsenic is set free to settle on the surround- 

 ing forage plants to make them unfit for stock. 



(3) Whether the waste when discharged into the irrigation 

 streams renders the water unfit for irrigation purposes and injures 

 the soil to which such water is applied. All of these problems were 

 studied, and definite data bearing thereon obtained. j 



The chemist in this investigation was accompanied by one of the/ 

 foresters of the Department of Agriculture. Samples of soil, foliage" 

 of trees, forage plants, irrigation waters, ores, and of the dump heap 

 were collected and forwarded to the Bureau of Chemistry for chem- 

 ical examination. As in the Tennessee investigation, samples of 

 foliage were collected from those trees which the forester was certain 

 had not died from insect pests, forest fires, crowding, or other com- 

 mon causes of forest destruction. 



A few paragraphs of introduction are necessary in regard to the 

 situation of the smelter and the appearance of the surrounding 

 country. 



LOCATION OF SMELTER AND APPEARANCE OF SURROUNDING 



VEGETATION. 



The Washoe smelter is situated on a high hill toward the southern 

 end of Deer Lodge Valley, which is about 35 miles long and from 4 

 to 6 miles wide. (See PI. VI.) It is located about at the junction 



