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Bacterial populations within copper mine tailings: long‐term effects of amendment with Class A biosolids
Author(s) -
Pepper I.L.,
Zerzghi H.G.,
Bengson S.A.,
Iker B.C.,
Banerjee M.J.,
Brooks J.P.
Publication year - 2012
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1111/j.1365-2672.2012.05374.x
Subject(s) - tailings , biosolids , amendment , copper mine , environmental science , soil water , microbial population biology , environmental chemistry , environmental engineering , copper , biology , chemistry , soil science , bacteria , law , organic chemistry , political science , genetics
Aim This study evaluates the effect of surface application of dried Class A biosolids on microbial populations within copper mine tailings. Methods and Results Mine tailing sites were established at ASARCO M ission M ine close to S ahuarita A rizona. Site 1 ( D ecember 1998) was amended with 248 tons ha −1 of Class A biosolids. Sites 2 ( D ecember 2000) and 3 ( A pril 2006) were amended with 371 and 270 tons ha −1 , respectively. Site D , a neighbouring native desert soil, acted as a control for the evaluation of soil microbial characteristics. Surface amendment of Class A biosolids showed a 4 log 10 increase in heterotrophic plate counts (HPCs) compared to unamended tailings, with the increase being maintained for 10‐year period. Microbial activities such as nitrification, sulphur oxidation and dehydrogenase activity were also sustained throughout the study period. 16S r RNA clone libraries obtained from community DNA suggest that mine tailings amended with biosolids achieve diversity and bacterial populations similar to native soil bacterial phyla, 10 years postapplication. Conclusion Addition of Class A biosolids to copper mine tailings in the desert south‐west increased soil microbial numbers, activity and diversity relative to unamended mine tailings. Significance and Impact of the Study The amended tailings resulted in a functional soil with respect to microbial characteristics, which were sustainable over a 10‐year period enabling the development of appropriate vegetation.