As(V)/Cr(VI) Retention on Un-Amended and Waste-Amended Soil Samples: Competitive Experiments

Online Resource

As(V)/Cr(VI) retention on un-amended and waste-amended soil samples: competitive experiments

Ivana M. Rivas-Pérez1, Manuel Conde-Cid2, Juan Carlos Nóvoa-Muñoz2, Manuel Arias-Estévez2, María

J. Fernández-Sanjurjo1, Esperanza Álvarez-Rodríguez1 and Avelino Núñez-Delgado1,*

1Department of Soil Science and Agricultural Chemistry, Engineering Polytechnic School, University of

Santiago de Compostela, Lugo 27002, Spain;

2Department of Plant Biology and Soil Science, Faculty of Sciences, Campus Ourense, University of

Vigo, Ourense 32004, Spain;

*Author to whom correspondence should be addressed; E-Mail: [email protected]; Tel: +34-982-

823-140; Fax: +34-982-823-001.

We used as individual materials a forest soil sample, a vineyard soil sample, pyritic material, finely ground mussel shell, pine bark, oak ash and hemp waste.

The forest soil sample was taken in the A horizon of a soil on granitic rocks, close to the Alcoa aluminum factory (San Cibrao, Lugo Province, Spain). The vineyard soil sample was from the A horizon of a soil on schists, in Sober (Lugo province, Spain). As indicated in Eimil-Fraga et al. (2015), the mineralogical composition of Galician soils on granitic substrates is characterized by variable amounts of quartz, K- feldspar, muscovite, biotite and plagioclase. Macías and Calvo (1992) indicate that the most common minerals present in Galician soils on schist are phyllosilicates 1:1 (mostly as kaolinite) and illite, with presence of inter-stratified illite-vermiculite and traces of Fe oxy-hydroxides. The pyritic material was from a copper mine spoil in Touro (A Coruña Province, Spain). The finely crushed (<1 mm) mussel shell was from the Abonomar S.L. factory (A Illa de Arousa, Pontevedra Province, Spain). Pine bark was a commercial product from Geolia (Madrid, Spain): we used the <0.63 mm particle size fraction after grounding and sieving. Oak ash was from a combustion boiler in Lugo (Spain). The hemp waste was

1 from an enterprise dealing with hemp-derived products, situated in Guitiriz (Lugo Province, Spain): we used the particle size between 0.63-5 mm.

The forest soil sample, the vineyard soil sample and the pyritic material were sampled in a zigzag manner

(0–20 cm depth), taking 10 subsamples to perform each final composite sample. These samples were air dried and sieved through 2 mm in the laboratory. Chemical determinations were carried out on the <2 mm fraction. All determinations were performed in triplicate.

C and N were quantified on 5 g samples using an elemental Tru Spec CHNS auto-analyzer (LECO

Corporation, St. Joseph, MI, USA), as per Chatterjee et al. (2009). A pH-meter (model 2001, Crison,

L’Hospitalet de Llobregat, Barcelona, Spain) was used to measure pH in water (10 g of solid sample, with solid:liquid relation 1:2.5), as well as to determine values corresponding to the point of zero charge

(pHpzc), as per Mimura et al. (2010). A 1 M NH4Cl solution was used to displace the exchangeable cations on 5 g samples, then measuring Ca, Mg and Al by means of atomic absorption spectroscopy, and Na and

K by atomic emission spectroscopy (AAnalyst 200, Perkin Elmer, Boston, MA, USA); the effective cationic exchange capacity (eCEC) was calculated as the sum of these cations. Total P was measured on 1 g samples by means of UV-visible spectroscopy (UV-1201, Shimadzu, Kioto, Japan) after nitric acid

(65%) microwave assisted digestion (Tan, 1996). Total concentrations of Na, K, Ca, Mg, Al, Fe, Mn, as well as As, Cd, Cr, Cu, Ni and Zn, were determined on 1 g samples by using ICP-mass spectrometry

(820-NS, Varian, Palo Alto, CA, USA), after nitric acid (65%) microwave assisted digestion (Nóbrega et al. 2012). Total amorphous Al and Fe (Alo, Feo) were quantified on 1 g samples using ammonium oxalate solutions acidified to pH 3 with oxalic acid (Álvarez et al. 2012). All trials were carried out by triplicate.

The results corresponding to the chemical characterization of the soil samples and by-products assayed are shown in Table S1. Furthermore, the particle-size distribution of forest and vineyard soil samples was determined using the Robinson pipette method. The particle size distribution results were: forest soil sample 65% sand, 20% silt and 15% clay; vineyard soil sample 73% sand, 12% silt and 15% clay. Thus, both soil samples presented the same average clay content, and both had sandy loam texture.

2 Table S1 General characteristics of the soil samples and waste materials assayed (average values for 3 replicates, with coefficients of variation always <5%). Xe: exchangeable concentration of the element; XT: total concentration of the element; Alo, Feo: extracted with ammonium oxalate

Fores Vineyard Pyritic Fine Oak Pine Hemp t soil material shell ash bark waste soil C (%) 4.22 2.94 0.26 11.43 11.65 46.95 36.53 N (%) 0.33 0.23 0.04 0.21 0.21 0.32 2.81

pHwater 5.65 4.48 2.97 9.39 11.31 3.99 8.70

pHpzc 5.53 4.14 3.46 9.94 12.52 4.00 9.00 -1 Cae (cmol(+) kg ) 4.37 1.78 0.36 24.75 95.03 5.38 31.15 -1 Mge (cmol(+) kg ) 0.66 0.24 0.29 0.72 3.26 2.70 3.67 -1 Nae (cmol(+) kg ) 0.33 0.14 0.14 4.37 12.17 0.46 4.19 -1 Ke (cmol(+) kg ) 0.60 0.83 0.24 0.38 250.7 4.60 21.82 -1 Ale (cmol(+) kg ) 1.92 2.28 2.86 0.03 0.07 1.78 <0.001 eCEC (cmol(+) kg-1) 7.88 5.27 3.89 30.25 361.2 14.92 60.83

PT (mg kg-1) 423.9 679.3 606.3 101.5 663.7 <0.01 1935 -1 CaT (mg kg ) 708.5 607.1 603.0 280168 13604 2319 13258 4 -1 MgT (mg kg ) 830.5 5003 8384 980.6 26171 473.6 6987 -1 NaT (mg kg ) 515.1 297.6 412.0 5173 2950 68.92 663.0 -1 KT (mg kg ) 1544 5441 3186 202.1 99515 737.8 10438 -1 AsT (mg kg ) 4.18 3.41 7.0 1.12 8.36 <0.001 0.76 -1 CdT (mg kg ) 0.43 0.14 0.08 0.07 19.93 0.13 0.08 -1 CrT (mg kg ) 18.35 41.44 99.0 4.51 36.28 1.88 8.66 -1 CuT (mg kg ) 15.72 521.1 773.0 6.72 146.33 <0.001 18.06 -1 NiT (mg kg ) 10.69 21.73 5.0 8.16 69.25 1.86 8.03 -1 ZnT (mg kg ) 36.74 49.57 58.0 7.66 853.0 6.98 73.86 -1 MnT (mg kg ) 92.99 305.4 296 33.75 10554 30.19 577.1 -1 AlT (mg kg ) 2267 25664 9624 433.2 14966 561.1 2307 6 -1 FeT (mg kg ) 9486 21284 135157 1855 12081 169.8 2061 -1 Alo (mg kg ) 4275 2003 563.0 178.3 8323 315.0 273.0 -1 Feo (mg kg ) 2333 1239 41860 171.0 4233 74.02 322.2

3 Table S2 pH values of the different suspensions resulting of adding 0 mmol L-1 of As(V) and Cr(VI) to individual materials (Alone), or to these materials amended with other sorbents, after have been shaken, centrifuged and filtered. pH values were determined using a pH-meter (model 2001, Crison, L’Hospitalet de Llobregat, Barcelona, Spain)

pH value Alone With oak ash With pine bark With hemp waste With mussel shell Forest soil 4.28 6.61 4.27 4.22 6.66 Vineyard soil 4.10 6.47 3.94 4.26 6.25 Pyritic material 3.28 7.21 3.64 3.67 5.86 Mussel shell 7.32 12.74 7.14 7.07 Oak ash 13.16 Pine bark 4.33 Hemp waste 7.05

4 References

Álvarez E, Fernández-Sanjurjo MJ, Núñez A, Seco N, Corti G (2012) Aluminium fractionation and

speciation in bulk and rhizosphere of a grass soil amended with mussel shells or lime. Geoderma

173/174:322–329

Chatterjee A, Lal R, Wielopolski L, Martin MZ, Ebinger MH (2009) Evaluation of Different Soil Carbon

Determination Methods. Cr Rev Plant Sci 28:164–178

Eimil-Fraga C, Álvarez-Rodríguez E, Rodríguez-Soalleiro R, Fernández-Sanjurjo MJ (2015) Influence of

parent material on the aluminium fractions in acidic soils under Pinus pinaster in Galicia (NW Spain).

Geoderma 255–256:50-57

Macías F, Calvo R (1992) Pedogeochemical characterization of the soils of Galicia (NW Spain) with

respect to lithological variations. Evidence of a transitional environment between temperate and

subtropical humid domains. Comptes Rendus de l'Académie des Sciences 315:1803–1810

Mimura AMS, Vieira TVA, Martinelli PB, Gorgulho HF (2010) Utilization of rice husk to remove Cu2+,

Al3+, Ni2+ and Zn2+ from wastewater. Química Nova 33(6):1279–1284

Nóbrega JA, Pirola C, Fialho LL, Rota G, de Campos CE, Pollo F (2012) Microwave-assisted digestion

of organic samples: How simple can it become? Talanta 98:272–276

Tan KH (1996) Soil sampling, preparation, and analysis. Marcel Dekker, New York