Evaluation of extractable elements in artificial substratum made from sewage sludge: Approach to remediation of degraded land in the Arctic

Abstract

AbstractThe Arctic (or subarctic) is characterized by a harsh climate and nutrient‐poor soil; what makes it even harsher in Monchegorsk (67°51′N and 32°48′E) is that metal pollution originating from the Ni–Cu smelting industry has severely damaged the soil and ground vegetation, resulting in formation of an industrial desert (barren ground). A pilot‐scale (4 ha) field test was carried out under such conditions to study how to apply municipal sewage sludge for rehabilitation of degraded land. After sewage sludge had been composted, an artificial substratum made from the compost was introduced to the remediation test field, and then willow, birch and grasses were planted on the substratum. The transformation of the artificial substratum was observed in the test field during 3 years. The portion of Cu in residual form was greater than that in other forms, it is hence considered that Cu has low bioavailability in the artificial substratum. Furthermore, the metal distributions statistically increased in fractions of humic acid (insoluble in water under acidic conditions), so the mobile amounts of Ni and Cu became small.The conclusion drawn from the field survey and analysis of extractable metals indicates that the lost vegetation is being restored even while pollution continues to be discharged from the smelter operation. Copyright © 2008 John Wiley & Sons, Ltd.