Trace ele­ments (microele­ments) in ground­wa­ter

The main doc­u­ment reg­u­lat­ing the qual­i­ty of drink­ing ground­wa­ter and deter­min­ing their suit­abil­i­ty for use is the State San­i­tary Rules and Norms DSan­Pin 2.2.4–171-10 “Hygien­ic require­ments for drink­ing water intend­ed for human con­sump­tion”.

These norms reg­u­late the con­tent of a large num­ber of micro­com­po­nents in ground­wa­ter for domes­tic and drink­ing pur­pos­es. Based on the speci­fici­ty of accu­mu­la­tion of these micro­com­po­nents in ground­wa­ter, they can be divid­ed into two groups.

The first group includes ele­ments whose per­mis­si­ble con­cen­tra­tions (PC) are usu­al­ly much high­er than their nat­ur­al (back­ground) con­cen­tra­tions in ground­wa­ter. Such ele­ments include cop­per, molyb­de­num, lead, and chromi­um, whose PC val­ues are 1.0, 0.07, 0.01, 1.0, and 0.05 mg/dm3, respec­tive­ly. These ele­ments gen­er­al­ly do not cre­ate prob­lems in the water sup­ply process, as their con­cen­tra­tions above the PC in ground­wa­ter are rare, only occur­ring in areas of sig­nif­i­cant techno­genic pol­lu­tion or local­ly in waters of min­er­al deposits.

The sec­ond group com­pris­es ele­ments whose PC are close to their back­ground con­cen­tra­tions in ground­wa­ter. These include iron (PC of 0.2 mg/dm3), flu­o­ride (1.5 mg/dm3), beryl­li­um (0.0002 mg/dm3), arsenic (0.01 mg/dm3), stron­tium (7.0 mg/dm3), and man­ganese (0.05 mg/dm3). The rel­a­tive­ly low PC lev­els of these ele­ments can be explained by their organolep­tic prop­er­ties — the abil­i­ty to neg­a­tive­ly affect water taste (iron and man­ganese) and tox­i­co­log­i­cal prop­er­ties (arsenic, beryl­li­um, stron­tium, and oth­ers).

A high (above PC) con­tent of sec­ond group ele­ments most often cre­ates prob­lems when using ground­wa­ter for house­hold and drink­ing pur­pos­es. Their high con­tent is most­ly of nat­ur­al ori­gin and wide­spread.

In Ukraine, for exam­ple, about 50% of wells used for domes­tic and drink­ing water sup­ply con­tain iron in amounts exceed­ing the PC. Ele­vat­ed iron con­tent is often observed in both deep (arte­sian) and shal­low (non-arte­sian) ground­wa­ter hori­zons. The high nat­ur­al con­tent of iron in ground­wa­ter requires appro­pri­ate water treat­ment mea­sures before sup­ply­ing such water to con­sumers.