An Evaluation of Revegetation Success on Bauxite Residue

Abstract

The current study was undertaken to evaluate the success of a revegetation program on three sites within the Bauxite Residue Disposal Area at the Aughinish Alumina Ltd. refinery. This was achieved by determining botanical diversity, substrate conditions, and plant uptake. Two sites revegetated in 1999, with and without the use of gypsum, were assessed and compared to a site revegetated in 1997. Compared to an initial 6 species used in seeding, a total of 47 species were recorded growing on the three sites with greatest diversity on the 1997 site. There was limited variation in the residue properties of the three treatments indicating that diversity was most influenced by succession and not substrate conditions. Limited available manganese was found in all treatments and significantly lower exchangeable magnesium in the gypsum-amended treatment. Exchangeable sodium, aluminum, and pH in the substrate were not at levels of concern. Appreciable nitrogen, phosphorus, and potassium were found as a result of a fertilizing program. Dominant species in the 1999 treatments, Holcus lanatus and Trifolium pratense, were analyzed for elemental composition. Compared to previous studies, foliar nitrogen, phosphorus, potassium, and calcium were adequate and sodium levels were low. Manganese and magnesium levels were low, and availability should be assessed as part of the monitoring program. Furthermore, the effect of a fertilizing regime on plant uptake and substrate conditions needs to be assessed.

Restauração Florestal de uma Mina de Bauxita: Avaliação do Desenvolvimento das Espécies Arbóreas Plantadas

“…A restauração florestal visa a criação de comunidades sustentáveis e representativas da composição e da diversidade das formações florestais em que a área degradada se insere (Jefferson, 2004;Courtney et al, 2009). Essa medida promove o avanço temporal dos processos ecológicos, da estrutura e da dinâmica sucessional, no sentido de que o novo ecossistema se aproxime em termos ecológicos do ecossistema de referência (Chazdon, 2008;Martins, 2014).…”

The History, Challenges, and New Developments in the Management and Use of Bauxite Residue

“…One particularly effective such rehabilitation project has been carried out using gypsum and manure additions at some former Rio Tinto Alcan owned residue sites in Kirkvine, Jamaica [12]. Very successful rehabilitation trials have been carried out by the University of Limerick and Rusal at the alumina refinery in Aughinish in Ireland which also used gypsum additions to bauxite residue [13,14].…”

Bauxite Residue Safety Disposal and Possibilities to Further Utilization. Part 1. Acid Soils Remediation

“…From thenceforth, the factory accumulated a good experience in processing this type of bauxite and started some projects carried out in its laboratory or in cooperation with other Romanian research -8 -Gheorghe Dobra, Laurentiu Filipescu… Bauxite Residue Safety Disposal and Possibilities to Further Utilization… institutes, trying to find new applications for the well characterized bauxite residue (bauxite residue chemical/mineralogical analysis and physical properties, new measurements of radioactivity, heavy metal content, composition and properties of the minimal processed bauxite residue at the disposal site location, and toxicity/irritation and dermal corrosivity thresholds) [1]. Many studies underlined that the bauxite residue application to any soil is very effective for reducing the phosphorous leaching, improving the pasture growth, ameliorating the soil acidity, increasing the plant metal sorption and decreasing the soluble metals concentration, and above all, the bauxite residue reduces the heavy metals availability [2][3][4][5][6][7]. But, the acid soil rehabilitation with bauxite residue is not just a simple problem of mixing and dispersing.…”

“…It should be avoided the pH values above 8.5-9.0 (promoting some larger increases in the concentrations of aluminium, vanadium and arsenic), as well as the low organic carbon and high clay content (promoting the heavy metal mobilization). This is the reason for the bauxite residue association with other materials rich in organic carbon [1][2][3][4][5][6][7].…”

“…It should be avoided the pH values above 8.5-9.0 (promoting some larger increases in the concentrations of aluminium, vanadium and arsenic), as well as the low organic carbon and high clay content (promoting the heavy metal mobilization). This is the reason for the bauxite residue association with other materials rich in organic carbon [1][2][3][4][5][6][7].Researches concerning the uses of bauxite residue in agriculture could be classified according to their disclosed specific purposes into two main groups: a) deep reshaping of the bauxite residue composition, capping and revegetation; b) change of the soils chemistry by bauxite residue metal immobilization and acid soils remediation. The common strategies for reaching these purposes are including: amendments of gypsum for reducing pH, balancing the sodicity, alkalinity, aluminum toxicity and improving porosity, and amendments of sand, clay or other materials for changing the water holding capacity of bauxite residue, Also, amendments of organic and inorganic fertilizers, supplied for providing minimal mineral nutrition and amelioration of C/N ratio are highly required.…”