Soil additives copper sulfate

The amount of silica in solution is reduced by the addition of metal salts. Thus spraying a rice plant and soil with copper sulfate solution reduced the amount of silica deposited in the leaves (121). This eHect is undoubtedly due to the formation of insoluble copper silicate, which thus rendered the silica unavailable. 

Copper sulfate can be described as a by-product of copper refining that is obtained by crystallization of the weak liquor. The copper sulfate precipitate formed is centrifuged, dried, screened, and finally packaged in bags and drum. However, it is produced in some chemical industries by reacting copper shot with sulfuric acid, air, and water. It is widely used as an insecticide, additive nutrients (for soils that are deficient in copper), copper electroplating, wood preservation, and in petroleum refining. 

The Ti-normalized data emphasize the enrichment in Cu at 10.5 cm (1987), a very striking feature of the MTR data. Associated with the copper peak are corresponding major peaks in S and IRM and lesser ones in Fe, Zn, and As (Zn only shows up as a peak in Ti-normalized plots). We believe these maxima at 10.5 cm are unrelated to power plant emissions. Copper sulfate is commonly added to reservoirs to retard algal growth. The manager of the water department in the town of Spencer, Lowell Hardmann, reported to us that copper sulfate was indeed added to the reservoir, but he did not have information on the exact date. Since Cu is not an element associated with power plant emissions and we know of no other significant Cu source nearby, the most likely explanation is that the copper sulfate additions were made in about 1987 coincident with the peak. The dramatic increase in Cu/Ti for reservoir sediments at 10.5 cm compared to nearby soils (Fig. 12) and rocks (Table 7b) is consistent with this conclusion. 

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