Abstract

RUIZ HUERTA, Esther Aurora  and  ARMIENTA HERNANDEZ, María Aurora. Accumulation of arsenic and heavy metals in maize near mine tailings. Rev. Int. Contam. Ambient [online]. 2012, vol.28, n.2, pp.103-117. ISSN 0188-4999.

Arsenic and metals Pb, Zn, Cu, Fe, Cd concentrations were determined in four substrates near mine tailings. After 70 days growth, accumulation of those elements and effects in the development of young maize (Zea mays L.) H-515, raised in greenhouse under controlled conditions (temperature, relative humidity and solar radiation) were also evaluated. Maize planted in substrates (S3 and S4) with higher concentrations of As and metals (Toxic metals and metalloids TMM) showed visible affectations such as: chlorosis, thinner leaves and growth inhibition. Zinc and Pb reached the highest contents among the studied elements in substrates and plants. In substrates, Zn concentrations ranged from 175.2 to 16193 mg/kg, and Pb from 66.5 to 6166 mg/kg. After 70 days growth, Zn concentrations in roots ranged from 54.7 to 3555.4 mg/kg, and Pb from 11.1 to 320.3 mg/kg. In the aerial part Zn contents varied from 30.8 to 519.8 mg/kg and Pb ranged from 3.7 to 38.5 mg/kg. Metal concentrations were also evaluated in 30 days growth maize plants. Zinc contents in roots ranged from 88.9 to 504.8 mg/kg, and Pb from 25.2 to 300.9 mg/kg; in the aerial part concentration ranges were 15.5 to 555.6 mg/kg for Zn, and 2.2 to 10.8 mg/kg for Pb. Generally low translocation (TF) and bioconcentration factors (BF) were determined for all elements. However, TF for Zn and Cd were slightly higher in plants after 30 and 70 days growth, with 0.86 and 0.85 for Cd and 0.82 for Zn in agricultural soils; arsenic had higher TF in all substrates for 70 days growth plants. Differences were also observed in maize development; plants grown in agricultural soils far from tailings showed better growth (46 cm on average) while those grown in tailings had lower growth (24 cm on average). Anatomic characteristics, fresh and dry weight, biomass and number of leaves also presented a similar behavior showing significant differences (p<0.05) among experimental units with S1 presenting the highest values, followed by S2, S3 and S4. Results suggest that TMM in zones close to tailings accumulate and affect young maize plants development, disturb their growth and cause phytotoxic effects that are shown in their appearance.

Keywords : farm soil; translocation factors; bioconcentration factors; greenhouse; phytotoxic effects.

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