There are also health concerns regarding eutrophic waters. So far, there have not been any reports of human illness or death from cyanotoxins from waters in Iowa. Municipalities also can contribute to the problem if they are not conscientious about storm drain management, street cleaning, and similar issues. Although inadequate sewage treatment was a problem, it has been largely corrected. But the number and size of agricultural operations in Iowa, use of fertilizer, and disturbance of soil surfaces means that P losses will be very high compared with normal urban impact.
Producers can keep P out of surface water by managing soil erosion and nutrient losses from runoff.
Improving tillage strategies, such as conservation tillage or no-till, using best management practices such as soil testing, and limiting P applications to soils where testing indicates P deficiencies can help. Buffers, grassed waterways, terraces, repair of erosion control devices, contour tillage, and other means of erosion reduction limit P losses as well. There is a role for P in aquatic systems. It is an essential element for life. Sediment transports P in loosely to tightly bound forms, and it is easy to cleave from particles through chemical or microbial action.