I3 EUTROPHICATION Nitrogen and phosphorus loadings to the lake [t yr-1](7, 26) T-N Sources Industrial Domestic Agricultural Natural Total --------------------------------------------------------------- 1960 405.5 1,021.3 2,047.7 1,986.9 5,461.4 1965 677.7 1,313.7 1,783.9 2,014.5 5,789.8 1970 1,281.4 1,821.3 1,804.0 2,033.9 6,940.6 1975 1,407.2 2,585.9 1,733.4 2,104.3 7,830.8 1980 2,089.2 3,248.0 1,726.9 2,131.9 9,196.0 T-P Sources Industrial Domestic Agricultural Natural Total --------------------------------------------------------------- 1960 110.3 88.4 98.4 70.4 367.5 1965 119 200.4 101 71.4 491.8 1970 372 348.7 119.6 72.2 912.5 1975 249 407.6 118.6 74.8 850 1980 371.1 497.4 120.7 75.8 1,065.0