Nutrient load carried by the River Po into the Adriatic Sea, 1968–1987

From the analytical data for orthophosphate phosphorus, nitrates and ammonia collected from 1968-1987 at the closure section of the River Po basin, we have evaluated the increase in the load of nutrients carried into the Adriatic by the largest Italian river. The load of orthophosphate phosphorus increased from 2000 t yr-1 in the years 1968-1970 to 5000 t yr-1 in 1980 and the total mineral nitrogen (nitrate plus ammonia) from 50 000 t yr-1 to 100 000 t yr-1 in the same period. The possible causes of these increases and the effects on the waters of the Northern Adriatic are discussed. © 1989.