The original purpose of the Regional Stream Sediment Geochemical Mapping data set was national general geochemical mapping and the basic assessment of environmental state. Other uses are, for example, the assessment of changes in environmental state and determination of the baseline concentrations of stream sediments.

The coordinates of the samples have been determined from 1:20 000 base maps or from smaller scale maps. Stream width, the flow rate, surrounding land-use and the sediment type at the sample site have been observed in the field. Other data are based on chemical analyses done in the laboratory.

Field observations are coded as follows:

Material

MU mud

LJ gyttja

X no data

Width of flow (stream) is given in metres.

The flow rate is estimated using a four degree scale:

1 standing water

2 clear flow

3 rapid flow

4 dry river bed

Surrounding land-use is coded as follows:

H clear cut area

M forest, bush

N meadow, uncultivated field

P cultivated field

S mire

T dense habitation

X unknown

Sediment/terrain type

HK sand

KA rock, boulder field, rock field

MR till

SA clay, silt

TU peat

XX unknown

Kansantl

X Additional determinations (mycobacteria) have been analysed from the sample at the National Institute for Health and Welfare (THL).

In Regional Stream Sediment Geochemical Mapping samples were collected using a (nylon) sieve cloth frame with a 0.06 mm mesh size over a distance on several dozen metres. The sample size was ca. 0.5 l. The coarsest mineral matter was removed by decanting and coarse organic matter was removed by sifting with a plastic sieve (ca. 2 mm mesh size). The samples were dried at a temperature of 60°C and ground fine with a plastic-bladed cutter. Finally, the samples were sieved to less than two mm grain size prior to chemical analysis. Detailed sampling descriptions are given in Lahermo et al. (1996) and for the year 2000 by Gregorauskiene et al. (2000).

The samples were analysed in the laboratory of Geological Survey of Finland (GTK) in Otaniemi. The laboratory is accredited in accordance with TO25 (EN ISO/IEC 17025).

The samples were dissolved in concentrated nitric acid in a microwave oven (US EPA 3051A) and analysed with an inductively coupled plasma mass spectrometer (ICP-MS) and with a plasma atomic emission spectrometer (ICP-AES). Mercury was determined with a cold vapour method. Carbon, hydrogen and nitrogen were determined using a LECO analyser.

In Regional Stream Sediment Geochemical Mapping samples were collected using a (nylon) sieve cloth frame with a 0.06 mm mesh size over a distance on several dozen metres. The sample size was ca. 0.5 l. The coarsest mineral matter was removed by decanting and coarse organic matter was removed by sifting with a plastic sieve (ca. 2 mm mesh size). The samples were dried at a temperature of 60°C and ground fine with a plastic-bladed cutter. Finally, the samples were sieved to less than two mm grain size prior to chemical analysis. Detailed sampling descriptions are given in Lahermo et al. (1996) and for the year 2000 by Gregorauskiene et al. (2000).

The samples were analysed in the laboratory of Geological Survey of Finland (GTK) in Otaniemi. The laboratory is accredited in accordance with TO25 (EN ISO/IEC 17025).

The samples were dissolved in concentrated nitric acid in a microwave oven (US EPA 3051A) and analysed with an inductively coupled plasma mass spectrometer (ICP-MS) and with a plasma atomic emission spectrometer (ICP-AES). Mercury was determined with a cold vapour method. Carbon, hydrogen and nitrogen were determined using a LECO analyser.

The samples were analysed in the laboratory of Geological Survey of Finland (GTK) in Otaniemi.

The field data have been combined with analytical results via a field code by using the SPSS program.

Aineisto