Engrais minéraux

Abstract

Mineral fertilizers are intended to correct soil deficiencies in inorganic nutrients, especially nitrogen, but also phosphorus and potassium. The most common are the so-called NPK that typically consist of ammonium nitrate, phosphorus and potassium salts. Intentional ingestion of a concentrated liquid fertilizer can result in severe poisoning because of the high potassium concentration of these formulations. Except for a few cases of dermatitis and dust-induced mucosal irritation, very few adverse effects have been reported in the occupational setting. Some fertilizers that contain calcium cyanamide can cause an antabuse reaction. Excessive use of mineral fertilizers lead to the contamination of underground water by nitrates, non volatile and highly hydrosoluble compounds that are subsequently found in drinking water. Nitrates have been claimed to cause methaemoglobinemia in newborns and cancer in the general population, especially of digestive tract. Recent data on their disposition as well as results of experimental and epidemiological studies conducted during the past 30 years show that their toxicity had been largely overestimated. Methaemoglobinemia in the newborn is actually related to a microbiological contamination of the drinking water. No causal link between long-term consumption of nitrate-rich drinking water and cancers in the general population could be demonstrated. Several collective expert reports concluded on the safety of nitrates and the inadequacy of current regulations. Recent in vitro investigations indicate that a physiological role of nitrates in humans as biocides is likely.