Chemical amendment and phytostabilization of an industrial residue contaminated with Zn and Cd

Abstract

Phytostabilisation of a contaminated soil with heavy metals is considered a very appropriate technology to reduce erosion and dispersion of contaminants. A greenhouse study was conducted to evaluate the effects of both chemical amendments (calcium silicate and brewery sludge), and phytoremediation using the grass Brachiaria decumbens, on an industrial residue contaminated with Zn and Cd (industrial residue). Industrial residue samples placed into 30 L containers were amended with 20% brewery sludge, calcium silicate (2%, 3%), and 20% of brewery sludge + calcium silicate (2.5%, 4%), and were compared to the control treatment (non-amended residue). After pH stabilization, B. decumbens plants were grown on all treatments in order to evaluate the ability of the species to tolerate high Zn and Cd concentrations from the residue. Samples were collected twice, at planting and harvesting, for pH determination and simple extractions with water, sodium nitrate, acetic acid and DTPA. Differences in Zn and Cd concentrations in extracts allowed to estimate the concentrations of these elements in the most likely chemical forms they are found in the residue.

Rehabilitation with forage grasses of an area degraded by urban solid waste deposits

“…The normal range, according toKabata-Pendias & Pendias (1992) is 100 to 400 mg kg -1 . Santos et al (2007) studied phytostabilization by B. decumbens of a contaminated industrial waste (Zn and Cd) treated with different methods: industrial waste (control); industrial waste + 20% sludge; industrial waste + calcium silicate (2%; 3%); and [industrial waste + 20% sludge] + calcium silicate (2.5%; 4%). These authors noted that B. decumbens tolerated Zn and Cd in industrial waste after it had been treated by chemical containment.…”

Vegetable species for phytoextraction of boron, copper, lead, manganese and zinc from contaminated soil

“…Among the few studies available in Brazil, many have been restricted to academics (Carneiro et al, 2001;Coscione and Berton, 2009;Gabos et al, 2009;Marques et al, 2000;Pereira et al, 2007;Romeiro et al, 2006;Santos et al, 2007;Zeittouni et al, 2007). In spite of that, promising species well known in Brazilian agriculture due to its robustness, good climate adaptation, deep root system and good biomass production have not been evaluated.…”

Escória de aciaria na redução da solubilidade e lixiviação de manganês em áreas contaminadas

“…A área está localizada próxima ao aterro de resíduos perigosos, com elevadas concentrações de Mn e outros elementos traço (SANTOS et al, 2007) Foram coletadas amostras das nove pilhas de resíduos, repartindo-se as pilhas em três partes iguais, extraindo-se amostras em três alturas relativas aos terços inferior, médio e superior das pilhas, segundo Norma 10007 (ABNT, 2004a). Essas nove pilhas de resíduos foram agrupadas por semelhanças nas características físicas e químicas (análise granulométrica, pH e teores de Mn no solubilizado), resultando em três grupos de resíduos (G1, G2 e G3) nos quais foram realizados os estudos.…”