Nitrous oxide production of heavy metal contaminated soil
Arsenic (As), lead (Pb), copper (Cu) and zinc (Zn) can be found in large concentrations in mine spills of central and northern Mexico. Interest in these heavy metals has increased recently as they contaminate drinking water and aquifers in large parts of the world and severely affect human health, b...
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Published in | Soil biology & biochemistry Vol. 38; no. 5; pp. 931 - 940 |
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Main Authors | , , , , , , |
Format | Journal Article |
Language | English |
Published |
Oxford
Elsevier Ltd
01.05.2006
New York, NY Elsevier Science |
Subjects | |
Online Access | Get full text |
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Summary: | Arsenic (As), lead (Pb), copper (Cu) and zinc (Zn) can be found in large concentrations in mine spills of central and northern Mexico. Interest in these heavy metals has increased recently as they contaminate drinking water and aquifers in large parts of the world and severely affect human health, but little is known about how they affect biological functioning of soil. Soils were sampled in seven locations along a gradient of heavy metal contamination with distance from a mine in San Luis Potosí (Mexico), active since about 1800 AD. C mineralization and N
2O production were monitored in an aerobic incubation experiment. Concentrations of As in the top 0–10
cm soil layer ranged from 8 to 22,992
mg
kg
−1, from 31 to 1845
mg
kg
−1 for Pb, from 27 to 1620
mg
kg
−1 for Cu and from 81 to 4218
mg
kg
−1 for Zn. There was a significant negative correlation between production rates of CO
2 and concentrations of As, Pb, Cu and Zn, and there was a significant positive correlation with pH, water holding capacity (WHC), total N and soil organic C. There was a significant negative correlation (
P<0.05) between production rate of nitrous oxide (N
2O) attributed to nitrification by the inhibition method in soil incubated at 50% WHC and total concentrations of Pb and Zn, and there was a significant positive correlation (
P<0.05) with pH and total N content. There was a significant negative correlation (
P<0.05) between the production rate of N
2O attributed to denitrification by the inhibition method in soil incubated at 100% WHC and total concentrations of Pb, Cu and Zn, and a significant positive correlation (
P<0.01) with pH; there was a significant positive correlation (
P<0.05) between the production of N
2O attributed to other processes by the inhibition method and WHC, inorganic C and clay content. A negative value for production rate of N
2O attributed to nitrifier denitrification by the inhibition method was obtained at 100% WHC. The large concentrations of heavy metals in soil inhibited microbial activity and the production rate of N
2O attributed to nitrification by the inhibition method when soil was incubated at 50% WHC and denitrification when soil was incubated at 100% WHC. The inhibitor/suppression technique used appeared to be flawed, as negative values for nitrifier denitrification were obtained and as the production rate of N
2O through denitrification increased when soil was incubated with C
2H
2. |
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Bibliography: | http://dx.doi.org/10.1016/j.soilbio.2005.08.007 ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0038-0717 1879-3428 |
DOI: | 10.1016/j.soilbio.2005.08.007 |