Nitrates in ground­wa­ter

Agri­cul­tur­al activ­i­ty is one of the most impor­tant neg­a­tive fac­tors affect­ing the qual­i­ty of ground­wa­ter, espe­cial­ly for shal­low ground­wa­ter that is prac­ti­cal­ly unpro­tect­ed from pol­lu­tion.

A sig­nif­i­cant por­tion of nitro­gen com­pounds intro­duced with fer­til­iz­ers is not absorbed by plants, and is instead car­ried away from the soil by rain or irri­ga­tion, ulti­mate­ly end­ing up in ground­wa­ter. As a result, in agri­cul­tur­al areas, the con­cen­tra­tion of these sub­stances in shal­low ground­wa­ter steadi­ly increas­es.

The rel­e­vance of these prob­lems for Euro­pean coun­tries led to the adop­tion of Coun­cil Direc­tive 91/676/EEC of 12 Decem­ber 1991 con­cern­ing the pro­tec­tion of waters against pol­lu­tion caused by nitrates from agri­cul­tur­al sources (Nitrate Direc­tive). Ter­ri­to­ries of a num­ber of states were declared vul­ner­a­ble to nitrate pol­lu­tion.

In Ukraine, where 70% of the ter­ri­to­ry is agri­cul­tur­al land, the issue of ground­wa­ter pol­lu­tion with nitrates is par­tic­u­lar­ly acute. With­in agro-land­scapes, it has a con­tin­u­ous nature. The high­est lev­els of nitrate con­tent are typ­i­cal for low-water south­ern regions, but even in the north­ern part of Ukraine, the nitrate con­tent in the water of the absolute major­i­ty of wells exceeds the reg­u­la­to­ry indi­ca­tor of 50 mg/dm3.

Anom­alous­ly high nitrate pol­lu­tion is asso­ci­at­ed with man­i­fes­ta­tions of water-nitrate methe­mo­glo­bine­mia, the symp­toms of which are headaches, dizzi­ness, short­ness of breath, nau­sea, and skin cyanosis. This dis­ease is more com­mon in peo­ple liv­ing in rur­al areas and con­sum­ing well water, but it is par­tic­u­lar­ly dan­ger­ous for chil­dren under 3 years of age. Unfor­tu­nate­ly, cas­es of infant mor­tal­i­ty due to res­pi­ra­to­ry cen­ter block­age caused by water-nitrate methe­mo­glo­bine­mia still occur. For exam­ple, in April 2018, in the Hlukhiv dis­trict of the Cherni­hiv region, a fatal case was record­ed when a 4‑month-old baby who was fed mix­tures based on water from a well died from nitrate poi­son­ing. The nitrate con­tent in the water was 800 mg/dm3!

For the sake of fair­ness, it should be not­ed that such exces­sive­ly high nitrate lev­els in water are of a local­ized nature and are caused more by con­t­a­m­i­na­tion of the water intake facil­i­ties than by the aquifer. Typ­i­cal­ly, such cas­es are the result of fail­ure to com­ply with hygiene require­ments dur­ing the con­struc­tion and oper­a­tion of wells.

Over­all, the qual­i­ty of ground­wa­ter in Ukraine neces­si­tates the need to restore its mon­i­tor­ing and take mea­sures to switch the pop­u­la­tion to water sup­ply from more pro­tect­ed arte­sian aquifers.