Table 1.

Quality control data for 11 nutrients by MMI® extraction of NGSA catchment outlet sediment samples (0–10 cm, <2 mm). LLD, Lower Limit of Detection; RSD (Std), Relative Standard Deviation for 22 analyses of laboratory standard SRM-18; RV, Recommended Value; Tolerance, Acceptable range about the Recommended Value; Bias, 100% × Average/Recommended Value; RSD (FD), Relative Standard Deviation for analyses of field duplicates (all FD data had <25% of values <LLD, except for Mo, which had <50% of values <LLD)

ElementLLD (ppm)Average (ppm)RSD (Std)RV (ppm)ToleranceBiasRSD (FD)
Ca101728%17334%100%31%
Cu0.010.6910%0.7024%98%30%
Fe1237%3120%73%50%
K0.124.64%N/AN/AN/A36%
Mg1944%10023%94%39%
Mn0.0050.4706%0.45023%104%43%
Mo0.0050.03611%0.03655%100%57%
Ni0.0050.5146%0.54022%95%36%
P0.10.721%N/AN/AN/A36%
Se0.0020.00785%N/AN/AN/A115%
Zn0.020.594%0.6827%87%50%