Evaluation of the chromium bioavailability in tanned

leather shavings using the SMampT sequential extractions

scheme

Lılian Irene Dias da Silva Fernanda Veronesi Marinho Pontes Manuel Castro CarneiroMaria Ines Couto Monteiro Marcelo Dominguez de Almeida and Arnaldo Alcover Neto

Coordenacao de Analises Minerais Centro de Tecnologia MineralndashCETEM Av Pedro Calmon 900 Cidade

Universitaria CEP 21941-908 Rio de Janeiro RJ Brazil

E-mail mmonteirocetemgovbr

ABSTRACT

Tanned leather shavings from Brazilian tanneries were analysed in order to assess the chromiumextractability and bioavailability and consequently its potential release into other environmental compart-ments when the shavings are deposited on landfill sites The conventional SMampT (Standard Measurementand Testing Programme) sequential extractions scheme was applied Also Cr(VI) and Cr(III) concentrationsin the oxidizable fraction were determined The results indicated high total chromium concentrations (104146 and 274) in the samples A B and C respectively A significant quantity of chromium (about 6ndash11of total chromium) was easily released in slightly acidic conditions (step 1) This fraction is the most labileand therefore the most dangerous and bioavailable for the surrounding environment Less chromium (1ndash3 of total chromium) was released in reducing conditions (step 2) whereas about 05ndash3 of totalchromium was strongly associated to the leather shaving structure (residual fractionndashstep 4) andtherefore its release under environmental conditions would be unlikely Most of chromium (about 83ndash92 of the total chromium) was bound to the organic matter as expected since it was released inoxidizing condition (step 3) Part of chromium released in this fraction was also converted into Cr(VI)which is more labile and toxic than Cr(III) Considering the chromium concentrations the sequentiallyextracted fractions may be ordered as follows oxidizable4exchangeable4reducible4residual

Keywords chromium speciation availability extraction tanned leather shavings

1 INTRODUCTION

The major leather production centres in the world are found

in Mexico Brazil Japan South Korea China India and

Pakistan Whereas Korea Japan and Italy import hides from

countries which have a large meat production industry the

South American countries such as Argentina and Brazil

process their own hides The leather industry is prevalent in

Brazil especially in the South in the Rio Grande do Sul

State where more than 50 of Brazilian leather is produced

(Basegio et al 2002)

In the tanning industry raw skin is transformed into

leather by means of a series of chemical and mechanical

processes (Alvarez-Bernal et al 2006 Basegio et al

2002) Skin in tanning process which is the main process

that protects the leather against some environmental effects

such as microbial degradation heat sweat or moisture is

stabilized by using a tannage material such as some mineral

and vegetable-based substances and aldehyde (Erdem and

Ozverdi 2008)

Trivalent chromium salts (in particular chromium sulfate)

are the most widely used tanning substances today About

90 of all hides are tanned with Cr(III) salts Hides that

have been tanned with chromium salts have a good

mechanical resistance an extraordinary dyeing suitability

and a better hydrothermal resistance in comparison with

hides treated with vegetable substances Chromium salts

also have a high rate of penetration into the interfibrillar

spaces of the skins This results in a saving in terms of

production time and a better control of the process (Basegio

et al 2002 Berry et al 2002)

The tanning industry generates substantial quantities of

waste One tonne of wet hide yields only 200 kg of leather

whereas over 600 kg of solid waste or by-product are

Chemical Speciation and Bioavailability (2011) 23(3) 183

wwwchemspecbiocouk

doi 103184095422911X13027118597382

generated Leather shavings constitute 75 of the solid

wastes containing chromium in the tanning process (Erdem

2006)

In the literature there are many studies which convert

tannery wastes to useful products (Basegio et al 2002

Dettmer et al 2010 Erdem 2006 Oliveira et al 2007

Trezza and Scian 2007 Yilmaz et al 2007) However

chromium-tanned leather consisting mainly of shavings

and finished parts is normally disposed on landfill sites

(Ferreira et al 2010 Yilmaz et al 2007) especially in

developing countries because of its low investment and

operational costs (Xiaoli 2007) Therefore solid wastes

from tannery industry deposited on landfill sites require

special attention because of the large amount produced

toxic and hazardous effects and legislative restrictions

(Basegio et al 2002 Berry et al 2002 Trezza and

Scian 2007 Yilmaz et al 2007)

The potential hazard of the wastes deposited on landfill

based on the total metal content is not enough to evaluate

the environmental impact because the chemical state in

which the metals are bound to wastes must be known to

evaluate their mobility and bioavailability (Perez-Lopez

et al 2008) Trace metals in wastes may exist in different

chemical forms or ways of binding

The environmental behavior of chromium depends on its

oxidation state Whereas Cr(III) compounds tend to form

relatively inert precipitates at near-neutral pH Cr(VI)

compounds are strong oxidizers and highly soluble and

therefore more toxic than Cr(III) compounds (Kotas and

Stasicka 2000 Losi et al 1994)

Single and sequential extractions schemes (SES) were

designed in the 1980s in order to assess the reten-

tionyrelease of metals in soil and sediment samples

(Quevauviller 2002 Rauret et al 2000 Prusty et al

2009) Later these procedures were applied to other

matrices Gupta and Sinha (2006) have studied the chemical

fractionation and heavy metal accumulation in a plant

grown on soil amended with tannery sludge using single

extractants Recently Rao et al (2008) have reviewed

extraction procedures applied for soil industrially contami-

nated soil sludge amended soil sewage sludge waste and

road dust and run-off

Sequential extractions procedures are the most used for

the determination of different forms of metals in wastes

such as mining wastes (Clevenger 1990 Marguı et al

2004 Perez-Lopez et al 2008) coal ash (Landsberger

et al 1995) municipal solid wastes (Xiaoli et al 2007)

and untreated industrial wastewater sludge (Kazi et al

2005) Only two works have been found for wastes from

the tannery industry Raju and Tandon (1999) have applied

the Stoverrsquos SES for tannery sludges in order to determine

the distribution of chromium into exchangeable adsorbed

organic carbonate and sulfide forms The sequence of

reagents extraction time and solution solid ratio were as

follows (i) 1 mol L 1 KNO3 16 h 50 1 (ii) 05 mol L 1

KF 16 h 80 1 (iii) 01 mol L 1 Na4P2O7 16 h 80 1 (iv)

01 mol L 1 EDTA 16 h 80 1 (v) and 1 mol L 1 HNO3

16 h 50 1 Chang et al (2001) have evaluated three

extraction tests ie toxicity characteristic leaching proce-

dures single extraction procedure and ASTM methods to

extract metals (Cd Cr Cu Ni Pb and Zn) in various

matrices including leather debris The use of the SMampT

(Standard Measurement and Testing Programme) sequen-

tial extractions scheme as well the chromium speciation in

the oxidizable fraction has not been reported for tanned

leather shavings

The aim of the present work was to study the chromium

concentration potentially bioavailable in tanned leather

shavings The SMampT sequential extractions scheme was

applied for leather shaving samples collected in different

Brazilian tanneries Also chromium species concentrations

in the oxidizable fractions were investigated

2 EXPERIMENTAL

21 Apparatus and operating conditions

The Cr extraction was performed by using a heated water-

bath model 572 (Fisatom Equipamentos Cientıficos Ltda

(Sao Paulo SP Brazil) a centrifuge model CT-6000

(Cientec Equipamentos para Laboratorios Piracicaba SP

Brazil) with 3200 rpm of speed and an orbital shaker

Marconi model MA141 (Piracicaba SP Brazil) A heated

plate Marconi model MA 239 (Piracicaba SP Brazil) was

used to digest the samples for total chromium determina-

tion A flame atomic absorption spectrometer model

SpectrAA 50 B from Varian Inc (Palo Alto CA USA)

was operated under the conditions recommended by the

manufacturer Acetylene (Linde RJ Brazil) and nitrous

oxide (White Martins RJ Brazil) with purities of 997

and 99 were used respectively The chromium hollow

cathode lamp was operated at 7 mA the absorbance

measurements were made at the 3579 nm wavelength and

a slit width of 02 nm was used Absorbance measurements

for determination of Cr(VI) were performed on a spectro-

photometer HACH model DR 5000 (Loveland Colorado

USA) using 1 cm quartz cuvettes and 540 nm of wave-

length

22 Reagents and samples

All solutions were prepared with analytical grade reagents

and ultra-pure water obtained from a reverse osmosis

system model Elix 5 coupled to a Milli-Q Gradient

model from Millipore (Barueri SP Brazil) All glassware

vessels were soaked in 12 (vyv) HNO3 for 24 h and rinsed

thoroughly with distilled water and finally rinsed for the

last time with ultra-pure water Standard stock solutions

containing 1000 mg L 1 Cr(VI) as K2CrO4 was prepared

from Fixanal concentrate (Riedel-de-Haen Seelze

Germany) Intermediate low concentration solutions were

prepared daily by dilution of the corresponding stock

solution with water Glacial acetic acid 997 hydroxyla-

mine hydrochloride ammonium acetate hydrogen peroxide

30 myv nitric acid 65 sulfuric acid 98 diphenilcar-

bazide and acetone were supplied by Vetec Quımica Fina

(Duque de Caxias RJ Brazil) Three tanned leather shaving

samples were collected in different Brazilian tanneries

184 Chromium bioavailability in tanned leather shavings

23 Procedures

The conventional SMampT (Standard Measurement and

Testing Programme) sequential extraction scheme

(Filgueiras et al 2002) is described as follows step 1

(acid-soluble and exchangeable fraction) ndash 20 mL of

011 mol L 1 acetic acid was added to 05 g of sample

without previous treatment in a 50 mL polypropylene

centrifuge tube and shaken for 16 h at room temperature

The phases were separated by centrifugation for 30 min and

the supernatant was separated for chromium determination

About 10 mL of water was added to the residue shaken for

15 min and centrifuged for 30 min The washing was

discarded and the residue was separated for the next step

step 2 (reducible fraction) ndash 20 mL of 01 mol L 1 hydro-

xylamine hydrochoride (adjusted to pH of about 2 by

adding nitric acid) was added to the residue from step 1

and shaken for 16 h at room temperature The phases were

separated by centrifugation for 30 min and the supernatant

was separated for chromium determination The residue was

washed with water as described in step 1 step 3 (oxidizable

fraction) ndash 5 mL of 30 (myv) hydrogen peroxide was

added to the residue from step 2 and occasionally and

manually shaken for 1 h at room temperature After that the

mixture was heated in a water-bath for 1 h at 85C and then

evaporated to almost dryness at 100C Then 5 mL of 30

(myv) hydrogen peroxide were added and the mixture was

heated in a water-bath for 1 h at 85C and then evaporated

to almost dryness at 100C After that 25 mL of 1 mol L 1

ammonium acetate were added and shaken for 16 h at room

temperature The phases were separated by centrifugation

for 30 min and the supernatant was separated for chromium

determination The residue was washed with water as

described in step 1 step 4 (residual fraction) ndash the residue

from step 3 was transferred to a glass beaker with the aid of

20 mL of nitric acid 1 1 Then the beaker was heated until

the residue was dissolved The solution was let to cool at

room temperature transferred to 25 mL volumetric flask

and the flask was filled to the mark with water This

solution was used for chromium determination

To evaluate the validity of the SMampT (Standard

Measurement and Testing Programme) sequential extrac-

tions scheme for Cr in each tanned leather shaving sample

we compared the sum of the chromium concentrations

found in each step with the value of total chromium

concentration The total chromium concentration was deter-

mined by using the procedure described in step 4 except

that about 2 g of sample and a 50 mL volumetric flask were

used

The following procedure was used for chromium(VI)

determination in the oxidizable fraction aliquots of

01 mL (samples A and B) and 5 mL (sample C) of

extracted oxidizable fraction were transferred to a 50 mL

volumetric flask The pH values were adjusted by adding

200 mL (for samples A and B) and 600 mL (for sample C) of

concentrated H2SO4 Then 1 mL of diphenilcarbazide 05

myv (025 g of diphenilcarbazide in 50 mL of acetone) was

added and the flask was filled to the mark with water The

solution was homogenized and let stand for 5 min for colour

development The Cr(III) concentration was calculated by

difference

3 RESULTS AND DISCUSSION

The extractable chromium concentrations in each sequential

extraction step and total chromium concentrations in tanned

leather shaving samples are shown in Table 1 The results

indicated high total chromium concentrations (104 146

and 274) in samples A B and C respectively The sums

of the Cr concentrations found in each step for all samples

were similar to the values of total chromium concentrations

(t-test confidence level of 95) validating the SMampT

scheme

The extracted chromium percent values with respect to

the sum of the four fractions are depicted in Figure 1 A

meaningful quantity of chromium (about 6 ndash 11 of total

chromium) was easily released in slightly acidic condition

A lower chromium fraction (1 ndash 3 of total chromium) was

released in reducing condition The most of chromium

(about 83 ndash 92 of total chromium) was released in

oxidizing condition whereas about 05 ndash 3 of total

chromium was strongly associated with the leather

shaving structure (residual fraction) and therefore its

release under environmental conditions would be unlikely

Considering the chromium concentrations the sequenti-

ally extracted fractions may be ordered as follows

oxidizable4exchangeable4reducible4residual

Table 2 shows the chromium species concentrations in

the oxidizable fraction whereas the chromium species

relative concentrations in this fraction are depicted in

Figure 2 About 48 5 and 09 of chromium of the

oxidizable fractions of the samples A B and C were

Lılian Irene Dias da Silva et al 185

Table 1 Total chromium concentrations and chromium concentrations in the SMampT sequential extraction scheme fractions for tannedleather shaving samples (n frac14 3)

Sample SMampT sequential extraction scheme fractions Total Cr (sum) Total Cr found() ()

Exchangeable Reducible Oxidizable Residual(mg kg 1) (mg kg 1) () (mg kg 1)

A 667+ 33 118+ 11 096+ 003 56+ 8 104+ 003 107+ 002

B 1102+ 21 164+ 37 133+ 004 75+ 18 146+ 001 145+ 004

C 2980+ 100 849+ 12 228+ 002 802+ 103 274+ 003 279+ 005

converted into Cr(VI) respectively The relative chromium

species concentrations in the oxidizable fractions varied

with the chromium concentrations in these fractions This

fact probably occurred because the addition of the oxidative

reagent was constant and not enough to oxidize all the

organic matter and Cr(III) specially in samples with higher

chromium concentrations The evidence of conversion of

Cr(III) into Cr(VI) in step 3 showed the risk of the disposal

of this type of waste in the environment under oxidative

conditions

4 CONCLUSION

High total chromium concentrations (104 146 and 274)

in samples A B and C were found respectively The

SMampS (Standard Measurement and Testing Programme)

sequential extractions scheme applied to evaluate the

potential mobility and the possible transfer of chromium

to the surrounding environment indicated that a significant

amount of chromium (about 6 ndash 11 of total chromium)

was easily released in slightly acidic condition (step 1) This

fraction is the most labile and therefore the most dangerous

and potentially bioavailable for the surrounding environ-

ment A lower chromium fraction (1 ndash 3 of total chro-

mium) was released in reducing condition (step 2) whereas

about 05 ndash 3 of total chromium was strongly associated to

the leather shaving structure (residual fraction ndash step 4) and

therefore its releasing under environmental conditions

would be unlikely Most of chromium (about 83 ndash 92 of

the total chromium) was bound to the organic matter as

expected since it was released in oxidizing condition (step

3) Part of chromium released in this fraction was also

converted into Cr(VI) which is more labile and toxic than

Cr(III) Considering the chromium concentrations the

sequentially extracted fractions may be ordered as

follows oxidizable4exchangeable4reducible4residual

REFERENCES

Alvarez-Bernal D Contreras-Ramos SM Trujillo-Tapia N

Olalde-Portugal V Frias-Hernandez JT and Dendooven L

(2006) Effects of tanneries wastewater on chemical and

biological soil characteristics Appl Soil Ecol 33 269ndash 277

Basegio T Berutti F Bernardes A and Bergmann CP (2002)

Environmental and technical aspects of the utilization of

tannery sludge as a raw material for clay products J Eur

Ceram S 22 2251ndash 2259

Berry FJ Costantini N and Smart LE (2002) Synthesis of

chromium-containing pigments from chromium recovered

from leather waste Waste Manag 22 761ndash 772

Chang EE Chiang PC Lu PH and Ko YW (2001) Compar-

isons of metal leachability for various wastes by extraction and

leaching methods Chemosphere 45 91 ndash 99

Clevenger TE (1990) Use of sequential extraction to evaluate the

heavy metals in mining wastes Water Air Soil Pollut 50

241ndash 254

Dettmer A Nunes KGP Gutterres M and Marcilio NR

(2010) Production of basic chromium sulfate by using recov-

ered chromium from ashes of thermally treated leather J

Hazard Mater 176 710ndash 714

Erdem M (2006) Chromium recovery from chrome shaving

generated in tanning process J Hazard Mater 129 143ndash

146

186 Chromium bioavailability in tanned leather shavings

Figure 1 Chromium fractionation patterns obtained by using the

SMampT sequential extractions scheme applied for tanned leather

shaving samples (n frac14 3)

Figure 2 Chromium species fractionation patterns in the oxidiz-

able fraction obtained by using the SMampT sequential extractions

scheme applied for tanned leather shaving samples (n frac14 3)

Table 2 Concentrations of Cr(VI) found and of Cr(III) calculatedin the oxidizable fraction of the SMampT sequential extractionscheme for tanned leather shaving samples (n frac14 3)

Sample Concentration ()

Cr(VI) found Cr(III) calculated

A 046+ 006 050+ 007

B 018+ 006 115+ 006

C 002+ 001 226+ 003

23 Procedures

The conventional SMampT (Standard Measurement and

Testing Programme) sequential extraction scheme

(Filgueiras et al 2002) is described as follows step 1

(acid-soluble and exchangeable fraction) ndash 20 mL of

011 mol L 1 acetic acid was added to 05 g of sample

without previous treatment in a 50 mL polypropylene

centrifuge tube and shaken for 16 h at room temperature

The phases were separated by centrifugation for 30 min and

the supernatant was separated for chromium determination

About 10 mL of water was added to the residue shaken for

15 min and centrifuged for 30 min The washing was

discarded and the residue was separated for the next step

step 2 (reducible fraction) ndash 20 mL of 01 mol L 1 hydro-

xylamine hydrochoride (adjusted to pH of about 2 by

adding nitric acid) was added to the residue from step 1

and shaken for 16 h at room temperature The phases were

separated by centrifugation for 30 min and the supernatant

was separated for chromium determination The residue was

washed with water as described in step 1 step 3 (oxidizable

fraction) ndash 5 mL of 30 (myv) hydrogen peroxide was

added to the residue from step 2 and occasionally and

manually shaken for 1 h at room temperature After that the

mixture was heated in a water-bath for 1 h at 85C and then

evaporated to almost dryness at 100C Then 5 mL of 30

(myv) hydrogen peroxide were added and the mixture was

heated in a water-bath for 1 h at 85C and then evaporated

to almost dryness at 100C After that 25 mL of 1 mol L 1

ammonium acetate were added and shaken for 16 h at room

temperature The phases were separated by centrifugation

for 30 min and the supernatant was separated for chromium

determination The residue was washed with water as

described in step 1 step 4 (residual fraction) ndash the residue

from step 3 was transferred to a glass beaker with the aid of

20 mL of nitric acid 1 1 Then the beaker was heated until

the residue was dissolved The solution was let to cool at

room temperature transferred to 25 mL volumetric flask

and the flask was filled to the mark with water This

solution was used for chromium determination

To evaluate the validity of the SMampT (Standard

Measurement and Testing Programme) sequential extrac-

tions scheme for Cr in each tanned leather shaving sample

we compared the sum of the chromium concentrations

found in each step with the value of total chromium

concentration The total chromium concentration was deter-

mined by using the procedure described in step 4 except

that about 2 g of sample and a 50 mL volumetric flask were

used

The following procedure was used for chromium(VI)

determination in the oxidizable fraction aliquots of

01 mL (samples A and B) and 5 mL (sample C) of

extracted oxidizable fraction were transferred to a 50 mL

volumetric flask The pH values were adjusted by adding

200 mL (for samples A and B) and 600 mL (for sample C) of

concentrated H2SO4 Then 1 mL of diphenilcarbazide 05

myv (025 g of diphenilcarbazide in 50 mL of acetone) was

added and the flask was filled to the mark with water The

solution was homogenized and let stand for 5 min for colour

development The Cr(III) concentration was calculated by

difference

3 RESULTS AND DISCUSSION

The extractable chromium concentrations in each sequential

extraction step and total chromium concentrations in tanned

leather shaving samples are shown in Table 1 The results

indicated high total chromium concentrations (104 146

and 274) in samples A B and C respectively The sums

of the Cr concentrations found in each step for all samples

were similar to the values of total chromium concentrations

(t-test confidence level of 95) validating the SMampT

scheme

The extracted chromium percent values with respect to

the sum of the four fractions are depicted in Figure 1 A

meaningful quantity of chromium (about 6 ndash 11 of total

chromium) was easily released in slightly acidic condition

A lower chromium fraction (1 ndash 3 of total chromium) was

released in reducing condition The most of chromium

(about 83 ndash 92 of total chromium) was released in

oxidizing condition whereas about 05 ndash 3 of total

chromium was strongly associated with the leather

shaving structure (residual fraction) and therefore its

release under environmental conditions would be unlikely

Considering the chromium concentrations the sequenti-

ally extracted fractions may be ordered as follows

oxidizable4exchangeable4reducible4residual

Table 2 shows the chromium species concentrations in

the oxidizable fraction whereas the chromium species

relative concentrations in this fraction are depicted in

Figure 2 About 48 5 and 09 of chromium of the

oxidizable fractions of the samples A B and C were

Lılian Irene Dias da Silva et al 185

Table 1 Total chromium concentrations and chromium concentrations in the SMampT sequential extraction scheme fractions for tannedleather shaving samples (n frac14 3)

Sample SMampT sequential extraction scheme fractions Total Cr (sum) Total Cr found() ()

Exchangeable Reducible Oxidizable Residual(mg kg 1) (mg kg 1) () (mg kg 1)

A 667+ 33 118+ 11 096+ 003 56+ 8 104+ 003 107+ 002

B 1102+ 21 164+ 37 133+ 004 75+ 18 146+ 001 145+ 004

C 2980+ 100 849+ 12 228+ 002 802+ 103 274+ 003 279+ 005

converted into Cr(VI) respectively The relative chromium

species concentrations in the oxidizable fractions varied

with the chromium concentrations in these fractions This

fact probably occurred because the addition of the oxidative

reagent was constant and not enough to oxidize all the

organic matter and Cr(III) specially in samples with higher

chromium concentrations The evidence of conversion of

Cr(III) into Cr(VI) in step 3 showed the risk of the disposal

of this type of waste in the environment under oxidative

conditions

4 CONCLUSION

High total chromium concentrations (104 146 and 274)

in samples A B and C were found respectively The

SMampS (Standard Measurement and Testing Programme)

sequential extractions scheme applied to evaluate the

potential mobility and the possible transfer of chromium

to the surrounding environment indicated that a significant

amount of chromium (about 6 ndash 11 of total chromium)

was easily released in slightly acidic condition (step 1) This

fraction is the most labile and therefore the most dangerous

and potentially bioavailable for the surrounding environ-

ment A lower chromium fraction (1 ndash 3 of total chro-

mium) was released in reducing condition (step 2) whereas

about 05 ndash 3 of total chromium was strongly associated to

the leather shaving structure (residual fraction ndash step 4) and

therefore its releasing under environmental conditions

would be unlikely Most of chromium (about 83 ndash 92 of

the total chromium) was bound to the organic matter as

expected since it was released in oxidizing condition (step

3) Part of chromium released in this fraction was also

converted into Cr(VI) which is more labile and toxic than

Cr(III) Considering the chromium concentrations the

sequentially extracted fractions may be ordered as

follows oxidizable4exchangeable4reducible4residual

REFERENCES

Alvarez-Bernal D Contreras-Ramos SM Trujillo-Tapia N

Olalde-Portugal V Frias-Hernandez JT and Dendooven L

(2006) Effects of tanneries wastewater on chemical and

biological soil characteristics Appl Soil Ecol 33 269ndash 277

Basegio T Berutti F Bernardes A and Bergmann CP (2002)

Environmental and technical aspects of the utilization of

tannery sludge as a raw material for clay products J Eur

Ceram S 22 2251ndash 2259

Berry FJ Costantini N and Smart LE (2002) Synthesis of

chromium-containing pigments from chromium recovered

from leather waste Waste Manag 22 761ndash 772

Chang EE Chiang PC Lu PH and Ko YW (2001) Compar-

isons of metal leachability for various wastes by extraction and

leaching methods Chemosphere 45 91 ndash 99

Clevenger TE (1990) Use of sequential extraction to evaluate the

heavy metals in mining wastes Water Air Soil Pollut 50

241ndash 254

Dettmer A Nunes KGP Gutterres M and Marcilio NR

(2010) Production of basic chromium sulfate by using recov-

ered chromium from ashes of thermally treated leather J

Hazard Mater 176 710ndash 714

Erdem M (2006) Chromium recovery from chrome shaving

generated in tanning process J Hazard Mater 129 143ndash

146

186 Chromium bioavailability in tanned leather shavings

Figure 1 Chromium fractionation patterns obtained by using the

SMampT sequential extractions scheme applied for tanned leather

shaving samples (n frac14 3)

Figure 2 Chromium species fractionation patterns in the oxidiz-

able fraction obtained by using the SMampT sequential extractions

scheme applied for tanned leather shaving samples (n frac14 3)

Table 2 Concentrations of Cr(VI) found and of Cr(III) calculatedin the oxidizable fraction of the SMampT sequential extractionscheme for tanned leather shaving samples (n frac14 3)

Sample Concentration ()

Cr(VI) found Cr(III) calculated

A 046+ 006 050+ 007

B 018+ 006 115+ 006

C 002+ 001 226+ 003

converted into Cr(VI) respectively The relative chromium

species concentrations in the oxidizable fractions varied

with the chromium concentrations in these fractions This

fact probably occurred because the addition of the oxidative

reagent was constant and not enough to oxidize all the

organic matter and Cr(III) specially in samples with higher

chromium concentrations The evidence of conversion of

Cr(III) into Cr(VI) in step 3 showed the risk of the disposal

of this type of waste in the environment under oxidative

conditions

4 CONCLUSION

High total chromium concentrations (104 146 and 274)

in samples A B and C were found respectively The

SMampS (Standard Measurement and Testing Programme)

sequential extractions scheme applied to evaluate the

potential mobility and the possible transfer of chromium

to the surrounding environment indicated that a significant

amount of chromium (about 6 ndash 11 of total chromium)

was easily released in slightly acidic condition (step 1) This

fraction is the most labile and therefore the most dangerous

and potentially bioavailable for the surrounding environ-

ment A lower chromium fraction (1 ndash 3 of total chro-

mium) was released in reducing condition (step 2) whereas

about 05 ndash 3 of total chromium was strongly associated to

the leather shaving structure (residual fraction ndash step 4) and

therefore its releasing under environmental conditions

would be unlikely Most of chromium (about 83 ndash 92 of

the total chromium) was bound to the organic matter as

expected since it was released in oxidizing condition (step

3) Part of chromium released in this fraction was also

converted into Cr(VI) which is more labile and toxic than

Cr(III) Considering the chromium concentrations the

sequentially extracted fractions may be ordered as

follows oxidizable4exchangeable4reducible4residual

REFERENCES

Alvarez-Bernal D Contreras-Ramos SM Trujillo-Tapia N

Olalde-Portugal V Frias-Hernandez JT and Dendooven L

(2006) Effects of tanneries wastewater on chemical and

biological soil characteristics Appl Soil Ecol 33 269ndash 277

Basegio T Berutti F Bernardes A and Bergmann CP (2002)

Environmental and technical aspects of the utilization of

tannery sludge as a raw material for clay products J Eur

Ceram S 22 2251ndash 2259

Berry FJ Costantini N and Smart LE (2002) Synthesis of

chromium-containing pigments from chromium recovered

from leather waste Waste Manag 22 761ndash 772

Chang EE Chiang PC Lu PH and Ko YW (2001) Compar-

isons of metal leachability for various wastes by extraction and

leaching methods Chemosphere 45 91 ndash 99

Clevenger TE (1990) Use of sequential extraction to evaluate the

heavy metals in mining wastes Water Air Soil Pollut 50

241ndash 254

Dettmer A Nunes KGP Gutterres M and Marcilio NR

(2010) Production of basic chromium sulfate by using recov-

ered chromium from ashes of thermally treated leather J

Hazard Mater 176 710ndash 714

Erdem M (2006) Chromium recovery from chrome shaving

generated in tanning process J Hazard Mater 129 143ndash

146

186 Chromium bioavailability in tanned leather shavings

Figure 1 Chromium fractionation patterns obtained by using the

SMampT sequential extractions scheme applied for tanned leather

shaving samples (n frac14 3)

Figure 2 Chromium species fractionation patterns in the oxidiz-

able fraction obtained by using the SMampT sequential extractions

scheme applied for tanned leather shaving samples (n frac14 3)

Table 2 Concentrations of Cr(VI) found and of Cr(III) calculatedin the oxidizable fraction of the SMampT sequential extractionscheme for tanned leather shaving samples (n frac14 3)

Sample Concentration ()

Cr(VI) found Cr(III) calculated

A 046+ 006 050+ 007

B 018+ 006 115+ 006

C 002+ 001 226+ 003

Erdem M and Ozverdi A (2008) Leaching behavior of chromium

in chrome shaving generated in tanning process and its

stabilization J Hazard Mater 156 51 ndash 55

Ferreira MJ Almeida MF Pinho SC and Santos IC (2010)

Finished leather waste chromium acid extraction and anaerobic

biodegradation of the products Waste Manag 30 1091ndash

1100

Filgueiras AV Lavilla I and Bendicho C (2002) Comparison of

the standard SMampT sequential extraction method with small-

scale ultrasound-assisted single extractions for metal partition-

ing in sediments Anal Bioanal Chem 374 103ndash 108

Gupta AK and Sinha S (2006) Chemical fractionation and

heavy metal accumulation in the plant of Sesamum indicum

(L) var T55 grown on soil amended with tannery sludge

selection of single extractants Chemosphere 64 161ndash173

Kazi TG Jamali MK Kazi GH Arain MB Afridi HI and

Siddiqui A (2005) Evaluating the mobility of toxic metals in

untreated industrial wastewater sludge using a BCR sequential

extraction procedure and a leaching test Anal Bioanal

Chem 383 297ndash 304

Kotas J and Stasicka Z (2000) Chromium occurrence in the

environment and methods of its speciation Environ Pollut

107 263ndash 283

Landsberger S Cerbus JF and Larson S (1995) Elemental

characterization of coal ash and its leachates using sequential

extraction techniques J Radioanalyt Nucl Chem 192 265ndash

274

Losi ME Amrhein C and Frankenberger WT Jr (1994)

Environmental biochemistry of chromium Rev Environ

Contam Toxicol 136 91 ndash 121

Marguı E Salvado V Queralt I and Hidalgo M (2004)

Comparison of three-stage sequential extraction and toxicity

characteristic leaching tests to evaluate metal mobility in

mining wastes Anal Chim Acta 524 151ndash 159

Oliveira LCA Goncalves M Oliveira DQL Guerreiro

MC Guilherme LRG and Dallago RM (2007) Solid

waste from leather industry as adsorbent of organic dyes in

aqueous-medium J Hazard Mater 141 344ndash 347

Perez-Lopez R Alvarez-Valero AM Nieto JM Saez R and

Matos JX (2008) Use of sequential extraction procedure for

assessing the environmental impact at regional scale of the Sao

Domingos Mine (Iberian Pyrite Belt) Appl Geochem 23

3452ndash 3463

Prusty BAK Chandra R and Azeez PA (2009) Chem Spec

Bioavail 21(3) 141ndash 151

Quevauviller Ph (2002) Operationally-defined extraction proce-

dures for soil and sediment analysis Part 3 New CRMs for

trace-element extractable contents Trends Anal Chem 21

774ndash 785

Raju M and Tandon SN (1999) Operationally determined

speciation of chromium in tannery sludges Chem Spec

Bioavail 11 67 ndash70

Rao CRM Sahuquillo A and Sanchez JFL (2008) A review

of the different methods applied in environmental geochem-

istry for single and sequential extraction of trace elements in

soils and related materials Water Air Soil Pollut 189 291ndash

333

Rauret G Lopez-Sanchez J-F Sahuquillo A Barahona E

Lachica M Ure AM Davidson CM Gomez A Luck

D Bacon J Yli-Halla M Muntau H and Quevauviller Ph

(2000) Application of a modified BCR sequential extraction

(three-step) procedure for the determination of extractable

trace metal contents in a sewage sludge amended soil reference

material (CRM 483) complemented by a three-year stability

study of acetic acid and ECTA extractable metal content J

Environ Monit 2 228ndash233

Trezza MA and Scian AN (2007) Waste with chrome in the

Portland cement clinker production J Hazard Mater 147

188ndash 196

Xiaoli C Shimaoka T Xianyan C Qiang G and Youcai Z

(2007) Characteristics and mobility of heavy metals in an

MSW landfill Implications in risk assessment and reclama-

tion J Hazard Mater 144 485ndash 491

Yilmaz O Kantarli IC Yuksel M Saglam M and Yanik J

(2007) Conversion of leather wastes to useful products

Resour Conserv Recy 49 436ndash 448

Lılian Irene Dias da Silva et al 187