Basis values for trace elements in groundwater sampled in national and provincial monitoring networks (LMG; PMG; LMB; Veluwe springs)
Basiswaarden voor spoorelementen in het grondwater van Nederland; gegevens uit landelijke en provinciale meetnetten (LMG; PMG; LMB; sprengen Veluwe)
26 May 2012, PDF |
43 pages |
Meinardi CR , Groot, MSM , Prins HF
RIVM Report 714801028
Basic groundwater values are concentrations in natural aerial deposition, multiplied by condensation factors derived from evapotranspiration in the actual landscape. They can serve as reference values for limit values and also for determining anthropogenic influences on groundwater. Groundwater basic values and basic values for atmospheric deposition in the Netherlands were derived from groundwater with long travel times in the soil, sampled in the national (LMG) and provincial groundwater monitoring networks (PMG). Groundwater from areas with natural vegetation, having resided a large time in a sandy soil, is discharged by the Veluwe sprengen, where investigations included the analysis of 50 trace elements. Comparison of the concentrations of trace elements in groundwater with travel times of more than 50 years under natural vegetation and those in Veluwe sprengen water showed the effects of variations in evapotranspiration, leading to different condensation factors. Human activities (acidification) cause high concentrations of metals in groundwater with short travel times under natural vegetation. Other trace elements and most major compounds have the highest concentrations in recent groundwater under agriculture (fertiliser). The national target levels for groundwater in LMG and PMG are often exceeded for Cd, Cu, Ni, Pb and Zn and, notably, for groundwater with the shortest travel times in the soil of both agricultural grounds and areas with natural vegetation. Recently infiltrated groundwater was observed in the National Soil Monitoring Network (LMB). Results indicated an increased aerial deposition of metal elements on natural vegetation showing a south to north trend over the Netherlands. Areas with intensive husbandry, sampled in LMB, show increased values for As and total-P, the concentrations of the other elements being only slightly higher if compared to normal agricultural soils.