Investigation of differences between field and laboratory pH measurements of national atmospheric deposition program/national trends network precipitation samples
Water, Air, & Soil Pollution
By: N. Latysh and J. Gordon
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Abstract
A study was undertaken to investigate differences between laboratory and field pH measurements for precipitation samples collected from 135 weekly precipitation-monitoring sites in the National Trends Network from 12/30/1986 to 12/28/1999. Differences in pH between field and laboratory measurements occurred for 96% of samples collected during this time period. Differences between the two measurements were evaluated for precipitation samples collected before and after January 1994, when modifications to sample-handling protocol and elimination of the contaminating bucket o-ring used in sample shipment occurred. Median hydrogen-ion and pH differences between field and laboratory measurements declined from 3.9 ??eq L-1 or 0.10 pH units before the 1994 protocol change to 1.4 ??eq L-1 or 0.04 pH units after the 1994 protocol change. Hydrogen-ion differences between field and laboratory measurements had a high correlation with the sample pH determined in the field. The largest pH differences between the two measurements occurred for high-pH samples (>5.6), typical of precipitation collected in Western United States; however low- pH samples (<5.0) displayed the highest variability in hydrogen-ion differences between field and laboratory analyses. Properly screened field pH measurements are a useful alternative to laboratory pH values for trend analysis, particularly before 1994 when laboratory pH values were influenced by sample-collection equipment.
Suggested Citation
Latysh, N., and Gordon, J., 2004, Investigation of differences between field and laboratory pH measurements of national atmospheric deposition program/national trends network precipitation samples: Water, Air, & Soil Pollution, v. 154, no. 1-4, p. 249-270, https://doi.org/10.1023/B:WATE.0000022971.59349.fc.
ISSN: 1573-2932 (online)
| Publication type | Article |
|---|---|
| Publication Subtype | Journal Article |
| Title | Investigation of differences between field and laboratory pH measurements of national atmospheric deposition program/national trends network precipitation samples |
| Series title | Water, Air, & Soil Pollution |
| DOI | 10.1023/B:WATE.0000022971.59349.fc |
| Volume | 154 |
| Issue | 1-4 |
| Year Published | 2004 |
| Language | English |
| Larger Work Type | Article |
| Larger Work Subtype | Journal Article |
| Larger Work Title | Water, Air, and Soil Pollution |
| First page | 249 |
| Last page | 270 |