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Use of Slaughterhouse Sludge in the Bioremediation of an Oxyfluorfen-Polluted Soil

Abstract

The use of organic matter is a highly accepted environmental practice among scientists for the bioremediation of polluted soils. In this manuscript we study under laboratory conditions the bioremediation capacity of a new biostimulant obtained from slaughterhouse sludge in a soil polluted by the oxyfluorfen at a rate of 4 l ha−1 (manufacturer’s rate recommended) over a 90-day period. We determined its effects on dehydrogenase, urease, β-glucosidase and phosphatase activities, the soil microbial community structure and the evolution of the herbicide in soil. Possibly due to the high content of low molecular weight proteins in the biostimulant, the enzymatic activities were stimulated mainly at the beginning of the experiment. Soil biological parameters were inhibited in oxyfluorfen-polluted soil. At the end of the experiment and compared with the control soil, dehydrogenase, urease, β-glucosidase, and phosphatase activities significantly decreased by 47.8%, 50.5%, 36.4%, and 45.5% in the oxyfluorfen-polluted soil. At 5 days into the experiment, the use of the biostimulant in oxyfluorfen-polluted soils decreased soil enzymatic activities and microbial community inhibition. At the end of the incubation period the oxyfluorfen concentration had decreased by 60% in the polluted soil and amended with biostimulants. These results suggested that the use of this biostimulant with higher amounts of low molecular weight proteins and peptides had a positive effect on the remediating oxyfluorfen-polluted soils. Therefore, this study provides the use of a new biostimulant obtained from slaughterhouse sludge by enzymatic hydrolysis processes used in the bioremediation of a soil polluted by the oxyfluorfen herbicide.

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Use of Slaughterhouse Sludge in the Bioremediation of an Oxyfluorfen-Polluted Soil

Author: Ávila Pozo, Paloma; Parrado Rubio, Juan; Caballero Jiménez, Pablo; Díaz López, Marta; Bastida López, Felipe; Tejada Moral, Manuel
Publisher: Springer
Year: 2021
DOI: 10.1007/s41742-021-00351-z
Source: https://idus.us.es/bitstreams/890eb918-b00e-4068-9c79-492c222f4fc3/download
Vol.:(0123456789)
1 3
In e na ional Jou nal o En i onmen al Resea ch (2021) 15:723–731
h ps://doi.o g/10.1007/s41742-021-00351-z
RESEARCH PAPER
Use o Slaugh e house Sludge in heBio emedia ion
o anOxy luo en‑Pollu ed Soil
PalomaÁ ila‑Pozo1· JuanPa ado2· PabloCaballe o2· Ma aDíaz‑López3· FelipeBas ida3· ManuelTejada1
Recei ed: 5 Janua y 2021 / Re ised: 10 May 2021 / Accep ed: 17 June 2021 / Published online: 25 June 2021
© The Au ho (s) 2021, co ec ed publica ion 2021
Abs ac
The use o o ganic ma e is a highly accep ed en i onmen al p ac ice among scien is s o he bio emedia ion o pollu ed
soils. In his manusc ip we s udy unde labo a o y condi ions he bio emedia ion capaci y o a new bios imulan ob ained
om slaugh e house sludge in a soil pollu ed by he oxy luo en a a a e o 4l ha−1 (manu ac u e ’s a e ecommended)
o e a 90-day pe iod. We de e mined i s e ec s on dehyd ogenase, u ease, β-glucosidase and phospha ase ac i i ies, he soil
mic obial communi y s uc u e and he e olu ion o he he bicide in soil. Possibly due o he high con en o low molecula
weigh p o eins in he bios imulan , he enzyma ic ac i i ies we e s imula ed mainly a he beginning o he expe imen . Soil
biological pa ame e s we e inhibi ed in oxy luo en-pollu ed soil. A he end o he expe imen and compa ed wi h he con ol
soil, dehyd ogenase, u ease, β-glucosidase, and phospha ase ac i i ies signi ican ly dec eased by 47.8%, 50.5%, 36.4%, and
45.5% in he oxy luo en-pollu ed soil. A 5days in o he expe imen , he use o he bios imulan in oxy luo en-pollu ed soils
dec eased soil enzyma ic ac i i ies and mic obial communi y inhibi ion. A he end o he incuba ion pe iod he oxy luo en
concen a ion had dec eased by 60% in he pollu ed soil and amended wi h bios imulan s. These esul s sugges ed ha he
use o his bios imulan wi h highe amoun s o low molecula weigh p o eins and pep ides had a posi i e e ec on he
emedia ing oxy luo en-pollu ed soils. The e o e, his s udy p o ides he use o a new bios imulan ob ained om slaugh-
e house sludge by enzyma ic hyd olysis p ocesses used in he bio emedia ion o a soil pollu ed by he oxy luo en he bicide.
A icle Highligh s
• Oxy uo en he bicide caused a nega i e e ec on soil biological p ope ies
• The applica ion o bios imulan s ob ained by enzyma ic hyd olysis om slaugh e house sludge dec eased he oxic
ac ion o oxy luo en
• The low molecula weigh p o ein o bios imulan s inc eased he deg ada ion o he bicide
The o iginal online e sion o his a icle was e ised due o add
unding no e.
* Manuel Tejada
[email p o ec ed]
1 G upo de In es igación Eda ología Ambien al,
Depa amen o de C is alog a ía, Mine alogía y Química
Ag ícola, E.T.S.I.A. Uni e sidad de Se illa, C a de U e a
km. 1, 41013Se ille, Spain
2 Depa amen o de Bioquímica y Biología Molecula ,
Facul ad de Fa macia, Uni e sidad de Se illa, C/P o . Ga cía
González 2, 41012Se ille, Spain
3 CEBAS-CSIC, Campus Uni e si a io de Espina do,
30100Mu cia, Spain
724 In e na ional Jou nal o En i onmen al Resea ch (2021) 15:723–731
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G aphic abs ac
Keywo ds Slaugh e house sludge· Bios imulan · Soil oxy luo en pollu ion· Soil biological p ope ies
In oduc ion
In he las decades he e has been a no able inc ease in he
amoun o sludge esul ing om slaugh e house was ewa e
ea men , a consequence o he inc ease in mea p oduc ion.
Bouwman e al. (2013) sugges ha by 2050 mea p oduc-
ion will ha e doubled. Consequen ly, i is e y likely ha
he inc ease in he numbe o slaugh e house acili ies o
lead o an inc ease in he olume o slaugh e house sludge
(Bus illo-Lecomp e and Meh a 2015).
Slaugh e house was ewa e has been classi ied by he
Uni ed S a es En i onmen al P o ec ion Agency as was e-
wa e ha m ul o he en i onmen (Al onso-Muniozgu en
e al. 2021) mainly due o i s high con en o o ganic ma e ,
suspended solids, oil and a s and nu ien s (Aziz e al. 2019;
Menegassi e al. 2020).
725In e na ional Jou nal o En i onmen al Resea ch (2021) 15:723–731
1 3
Cu en ly, one o he mos widely used bio emedia ion
echniques among he scien i ic communi y is he applica-
ion o o ganic ma e o pollu ed soil, because i is a e y
cheap, e ec i e echnique ha can be pe o med insi u
(Da in e al. 2018). In hese cases, o ganic ma e educes
he concen a ion o con aminan in he soil ia wo di e -
en pa hways. Fi s ly, his o ganic ma e has he capaci y o
adso b he oxins, dec easing hei concen a ion in he soil
solu ion and consequen ly educing hei oxici y. Second,
he addi ion o his o ganic ma e s imula es he g ow h o
hose mic oo ganisms ha a e ole an o he oxins p esen s
in he soil. In doing so, he mic oo ganisms inc ease he
a e o pollu an deg ada ion and so dec ease hei soil con-
cen a ion (Gómez e al. 2014; Lipczynska-Kochany 2018;
O iz-Bo ella e al. 2021). Howe e , o his o ganic ma e
o be able o s imula e hese soil mic oo ganisms, he e is
a delay, while i is mine alized in o simple o ms ha a e
mo e easily a ailable o he said mic oo ganisms (O iz-
Bo ella e al. 2021).
Using his slaugh e house sludge o manu ac u e new
edaphic bios imulan (BS) ob ained by enzyma ic hyd olysis
p ocesses would, he e o e, ha e impo an socioeconomic
and en i onmen al impac s. On he one hand, he e would be
a solu ion o he accumula ion o his o ganic was e and, on
he o he , he sludges could be o g ea use o bio emedia -
ing pes icide-pollu ed soils.
This s udy was p omp ed o ob ain a new BS ob ained
om slaugh e house sludge o bio emedia e a soil con ami-
na ed wi h he oxy luo en he bicide, which exe s a pe sis-
en oxic e ec on soil biological p ope ies (Gómez e al.
2014; Rod íguez-Mo gado e al. 2014; F anco-And eu e al.
2016; Campos e al. 2019). Ou hypo hesis is suppo ed by
he exis ence o o he BS ob ained by enzyma ic hyd olysis
p ocess om di e en o ganic was es such as sewage sludge,
chicken ea he s, oka a, ice b an, e c. used in he bio e-
media ion o soils pollu ed by a ious pes icides (Gómez
e al. 2014; Tejada e al. 2010, 2011a, b, 2014; Rod íguez-
Mo gado e al. 2014, 2015a; O s e al. 2017). These BS a e
cha ac e ized by p esen ing a high numbe o low molecula
weigh pep ides, amino acids, e c. ha a e easily abso bed
by soil mic oo ganisms, hus accele a ing he deg ada ion o
he pollu an in he con amina ed soil.
The e is an abundan bibliog aphy ha sugges s unde -
s anding he beha iou o any xenobio ic in soil equi es he
s udy o biological pa ame e s (Campos e al. 2019; Wołejko
e al. 2020). This is because hese biological pa ame e s
eac much as e han physical and chemical ones (Kadian
e al. 2012; F anco-And eu e al. 2016; O s e al. 2017).
The e o e, he s udy o soil enzyma ic ac i i ies could be
e y use ul o unde s and he e ec o slaugh e house sludge
on he bio emedia ion o oxy luo en-pollu ed soils.
Wi hin he ame wo k o his hypo hesis, he aims we e:
(1) o ob ain a new bios imulan c ea ed om slaugh e house
sludge ia enzyma ic hyd olysis p ocesses, and (2) o s udy
he e ec i eness o slaugh e house sludge as a BS in he
bio emedia ion o a soil pollu ed by oxy luo en, p incipally
s udying i s epe cussion on he a ge soil’s biochemical
p ope ies.
Ma e ial andMe hods
Cha ac e is ics o O ganic Was es, Soil andHe bicide
The slaugh e house sludge was supplied by he “Ma ade o
del Su ” company, loca ed in Sal e as (Se ille, Spain). This
sludge was subjec ed o wo di e en ea men s o ob ain
wo di e en o ganic p oduc s.
The i s o he ea men s consis ed o concen a ing he
slaugh e house sludge un il eaching a d y ma e alue o
15%, since a his alue, an easily manageable p oduc is
ob ained. This concen a ion was ca ied ou a 75°C wi h
a o a y e apo a o . This i s o ganic compound is called
concen a ed slaugh e house sludge (SS).
The second o ganic compound was ob ained by subjec -
ing he slaugh e house sludge o an enzyma ic hyd olysis
p ocess. The hyd olysis p ocess was pe o med in a bio e-
ac o acco ding o he pH–s a me hodology (Adle -Nissen
1977). Figu e1 shows he condi ions unde which his bio-
chemical p ocess was pe o med. Once he soluble p oduc
was ob ained, i was also concen a ed o 15% a 75°C wi h
a o a y e apo a o . This second o ganic compound is called
BS ob ained om slaugh e house sludge.
Table1 shows he chemical composi ion o bo h o ganic
compounds. The me hodology measu ing each chemical
pa ame e is de ailed in Rod íguez-Mo gado e al. (2015b).
The expe imen al soil used was a Calca ic Regosol (FAO
1989). The soil cha ac e is ics a e shown in Table1. The
analy ical me hods used in de e mining hese soil pa ame e s
a e de ailed in Tejada e al. (2014).
Oxy luo en was used as expe imen al he bicide a a e
o 4l ha−1 ( ecommended applica ion a e). The comme cial
o mula ion Fen en (24% p −1, 240g l−1) was pu chased
om Lainco, S.A (Spain).
Expe imen al Design
Th ee hund ed g ams o d ied soil was mixed wi h oxy luo -
en and ea ed wi h SS a a andom a e o 3% (9g o p od-
uc ) and BS a a a e o 3.9% (11.7g o p oduc ) o apply he
same amoun o o ganic ma e o he soil (5.84g o ganic
ma e pe kg o soil). A non-amended and non-pollu ed soil
was used as con ol. The incuba ion ea men s we e de ailed
in Table2.
Bo h o ganic compounds we e liquid and we e solubi-
lized in dis illed wa e be o e applying.
726 In e na ional Jou nal o En i onmen al Resea ch (2021) 15:723–731
1 3
T iplica e ea men s we e kep in mic ocosms a
25 ± 1°C o 90days. Dis illed wa e was added o each
soil o each 30–40% o i s wa e -holding capaci y and he
mois u e losses we e compensa ed by adding dis illed wa e .
Soil Analysis
Dehyd ogenase, u ease, β-glucosidase and phospha ase
ac i i ies o each ea men we e de e mined in iplica e a
days 5, 10, 20, 35, 55 and 90 using he me hods desc ibed
by Ga cía e al. (1994), Kandele and Ge be (1988), Ei azi
and Taba abai (1988) and Taba abai and B emne (1969).
Fo each expe imen al ea men , mic obial a y acids
we e de e mined in iplica e a days 5 and 90 o he expe i-
men . Es e -linked mic obial a y acids we e ex ac ed
and quan i ied acco ding o he me hodology desc ibed
by Mon es de Oca-Vásques e al. (2020). The a y acids
i15:0, a15:0, i16:0, and i17:0 we e ep esen a i e o he
G am + (G +) bac e ial biomass, whe eas he a y acids
18:1ω c, 18:1ω9 , cy17:0, and cy19:0 we e ep esen a i e
o he G am- (G-) bac e ial biomass (Ba dge e al. 1996;
Dungai e al. 2010). The a y acid 18:2ω6 we e ep esen a-
i e o he ungal biomass (Zelles e al. 1992; Båå h 2003).
A days 5, 10, 20, 35, 55 and 90, he soil oxy luo en
con en was de e mined. Soil oxy luo en was ex ac ed
acco ding o he Anas assiades e al. (2003) me hod. The
me hodology measu ing he he bicide is desc ibed in
Rod íguez-Mo gado e al. (2014). The limi o de ec ion
(LOD) was 0.006mg kg−1 and he limi o quan i ica ion
(LOQ) 0.01mg kg−1.
Fig. 1 Enzyma ic hyd olysis p ocess used o ob aining bios imulan
om slaugh e house sludge
Table 1 Chemical cha ac e is ics and p o ein molecula weigh dis-
ibu ion (mean ± s anda d e o , n = 3) o soil, slaugh e house sludge
and bios imulan ob ained by slaugh e house sludge by enzyma ic
hyd olysis p ocess
Files ollowed by he same le e (s) a e no signi ican ly di e en
acco ding o he Tukey es (p < 0.05)
SS slaugh e house sludge, BS bios imulan ob ained by slaugh e -
house sludge
Pa ame e s Soil SS BS
pH (H2O) 7.6 ± 0.2
Sand (g kg−1)554 ± 28
Sil (g kg−1)134 ± 21
Clay (g kg−1)312 ± 31
D y ma e (%) 15.2a ± 2.1 15.8a ± 1.7
O ganic ma e (g kg−1)18.3b ± 1.8 789a ± 37 649a ± 22
N (g kg−1)0.9b ± 0.2 3.5a ± 1.4 3.0a ± 1.1
P (g kg−1)5.6a ± 2.1 5.4a ± 1.8
K (g kg−1)9.1a ± 2.6 8.9a ± 2.7
S (g kg−1)12.8a ± 3.3 11.7a ± 2.1
Ca (g kg−1)29.4b ± 5.8 15.3a ± 1.6
Mg (g kg−1)1.6a ± 0.4 1.5a ± 0.7
Fe (g kg−1)8.4b ± 1.7 3.0a ± 0.9
Cu (mg kg−1)139a ± 28 85.7a ± 14.3
Mn (mg kg−1)148b ± 14 44.3a ± 13.5
Zn (mg kg−1)510b ± 21 333a ± 18
Pb (mg kg−1)10.6b ± 2.3 5.7a ± 2.0
Ni (g kg−1)10.4a ± 1.7 7.8a ± 1.1
P o ein molecula weigh dis ibu ion (Da)
 > 10,000 77.4b ± 3.4 50.0a ± 2.7
10,000–5000 3.4a ± 1.6 4.8a ± 1.7
5000–3000 2.1a ± 0.5 2.9a ± 1.1
3000–1000 3.8a ± 1.2 5.9a ± 1.3
1000–300 3.3a ± 1.7 6.8a ± 1.6
 < 300 10.0a ± 1.9 29.6b ± 2.4
Table 2 Scheme o he incuba ion ea men s pe o med
(1) C, con ol soil, non-amended and wi hou he bicide
(2) C + SS, soil amended wi h SS and wi hou he bicide
(3) C + BS, soil amended wi h BS and wi hou he bicide
(4) C + Ox, soil non-o ganically amended and wi h he bicide
(5) C + Ox + SS, soil amended wi h SS and wi h he bicide
(6) C + Ox + BS, soil amended wi h BS and wi h he bicide
727In e na ional Jou nal o En i onmen al Resea ch (2021) 15:723–731
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S a is ical Analysis
To de e mine he di e ences be ween he esul s ob ained
o each pa ame e analysed, he da a we e submi ed o
wo-way analysis o a iance (ANOVA) using wo ac o s
( ea men s and sampling ime). This was hen ollowed by
he Tukey pos -hoc es (HSD, p < 0.05). The ANOVA was
pe o med using he S a g aphics Plus 2.1 so wa e package.
Fo he s a is ical analysis, iplica e da a we e used o each
ea men and each day o incuba ion.
Resul s andDiscussion
A e he enzyma ic hyd olysis p ocess and wi h espec o
he SS, he BS showed a signi ican (p < 0.05) dec ease in
he Ca and mic onu ien s concen a ion (Table1). I was
also obse ed ha signi ican changes occu ed in he p o ein
molecula weigh dis ibu ions. In his espec , and compa ed
wi h he SS, he p o eins wi h he highes molecula weigh
(> 1000 KDa) in he new BS dec eased by 35.4%. Also,
and wi h espec o he SS, he 1000–300Da and < 300Da
molecula weigh p o eins in he new BS inc eased signi i-
can ly by 51.5% and 66.2%.
The applica ion o SS and BS signi ican ly (p < 0.05)
s imula ed he soil enzyma ic ac i i ies s udied (Tables3 and
4). Compa ed wi h he C ea men , he applica ion o SS o
he soil p og essi ely inc eased he dehyd ogenase, u ease,
β-glucosidase and phospha ase ac i i ies by 65.7%, 70.3%,
78.8% and 68%, espec i ely. Howe e , he beha io o he
enzyma ic ac i i ies s udied a e applying he BS o he
soils was e y di e en . Dehyd ogenase, β-glucosidase and
phospha ase ac i i ies eached maximum s imula ion 5days
a e he s a o he expe imen , hen g adually dec easing
un il 35days a e he expe imen . F om his da e, he dehy-
d ogenase, β-glucosidase and phospha ase ac i i y began
o inc ease again un il he end o he incuba ion pe iod,
eaching a highe alue han ha ob ained in he con ol
ea men . In his sense, he s imula ion o dehyd ogenase,
β-glucosidase and phospha ase ac i i ies was 54%, 68.6%
and 59.8.
Compa ed wi h he C + SS ea men , a e he appli-
ca ion o he BS o he soil, he beha io o he u ease
ac i i y was e y simila h oughou he incuba ion pe iod
(Table3).
We hink ha he cause o he di e en beha iou in he
wo expe imen al o ganic was es can be due o he di e -
ence in he molecula p o ein weigh dis ibu ion pe cen -
age. Ou esul s highligh ha in bo h o ganic was es he
p o ein size dis ibu ion di e s mainly in sizes o > 1000Da
and < 300Da. The SS has a highe pe cen age o high molec-
ula weigh p o eins, while BS showed a highe pe cen age
o low molecula weigh p o eins. Since he mic oo gan-
isms in he soil canno di ec ly abso b he high molecula
weigh p o eins, o ob ain ene gy hese mic oo ganisms need
o deg ade hem. This mine alisa ion p ocess is usually slow,
and he e o e, mic obial s imula ion in he SS-amended soil
inc eased p og essi ely h oughou he expe imen al pe iod.
Acco ding o Rod íguez-Mo gado e al. (2015b), when
applying BS o he soil, mic oo ganisms di ec ly abso b
hese low molecula weigh p o eins, a ou ing hei s imu-
la ion. The subsequen dec ease in hei enzyma ic ac i i ies
o alues simila o he con ol a day 35 sugges ha by
hen soil mic oo ganisms had al eady consumed hese low
Table 3 E olu ion o
dehyd ogenase and u ease
ac i i ies (mean ± s anda d
e o , n = 3) in soils amended
wi h slaugh e house sludge
(SS) and hyd olysa e
slaugh e house sludge (BS) and
wi h oxy luo en du ing he
expe imen al pe iod
Columns ollowed by he same le e (s) a e no signi ican ly di e en (p > 0.05)
INTF 2-p-iodo-3-ni ophenyl o mazan
Incuba ion days
5 10 20 35 55 90
Dehyd ogenase ac i i y (µg INTF g−1 h−1)
C 2.7b ± 0.6 2.8b ± 0.4 2.5b ± 0.3 2.3b ± 0.2 2.4b ± 0.3 2.3b ± 0.3
C + SS 4.1c ± 0.9 4.9c ± 1.0 5.1c ± 1.2 5.4c ± 1.1 6.1c ± 1.4 6.7c ± 1.5
C + BS 15.2d ± 2.6 6.8c ± 1.7 5.7c ± 0.8 4.2c ± 0.5 4.5c ± 0.8 5.0c ± 1.1
C + Ox 1.3a ± 0.2 1.4a ± 0.3 1.1a ± 0.1 1.4a ± 0.3 1.5a ± 0.2 1.2a ± 0.3
C + Ox + SS 2.7b ± 0.5 3.3b ± 0.8 4.4c ± 1.0 4.7c ± 0.8 4.9c ± 1.1 5.4c ± 0.8
C + Ox + BS 10.3d ± 1.9 5.5c ± 0.7 4.0c ± 0.7 3.7bc ± 0.6 3.7bc ± 0.7 4.1c ± 1.0
U ease ac i i y (µg NH4+ g−1 h−1)
C 1.7b ± 0.2 1.7b ± 0.2 1.8b ± 0.1 1.7b ± 0.2 1.8b ± 0.3 1.9b ± 0.3
C + SS 2.7b ± 0.9 3.2bc ± 0.6 3.7c ± 0.8 4.8c ± 1.0 5.2c ± 0.9 6.4c ± 1.7
C + BS 2.9b ± 1.1 3.4bc ± 0.8 4.0c ± 1.0 4.7c ± 0.8 5.8c ± 0.6 6.9c ± 0.8
C + Ox 0.94a ± 0.13 0.98a ± 0.12 0.91a ± 0.13 0.83a ± 0.17 0.90a ± 0.09 0.94a ± 0.11
C + Ox + SS 1.7b ± 0.6 2.2b ± 0.6 2.9b ± 0.7 3.0b ± 0.8 3.8c ± 0.6 4.5c ± 1.0
C + Ox + BS 2.2b ± 0.4 2.5b ± 0.4 2.7b ± 0.5 2.7b ± 0.6 3.1bc ± 0.8 3.4c ± 0.7

728 In e na ional Jou nal o En i onmen al Resea ch (2021) 15:723–731
1 3
molecula weigh p o eins. The p og essi e inc ease om
day 35 on he soil biochemical ac i i y is a consequence
o he ac ha he BS s ill showed a high numbe o high
molecula weigh p o eins, implying ha , as o his day,
soil mic oo ganisms began o exc e e ex acellula enzymes
o ob ain ene gy. This means ha he e was a p og essi e
inc ease in he soil biochemical ac i i y un il he end o he
incuba ion pe iod.
The soil beha iou o his new BS ob ained om slaugh-
e house sludge di e s g ea ly om ha ob ained om o he
BSs also by enzyma ic hyd olysis using he same enzyme
om sewage sludge, chicken ea he s, ice b ain, condensed
dis illa es o soluble whea , and oka a, which, a e applica-
ion, caused an inc ease in he soil biological ac i i y du -
ing he i s days o incuba ion. Subsequen ly his ac i i y
dec eased and showed a biochemical ac i i y simila o ha
o a non-pollu ed soil (Tejada e al. 2010, 2011b, 2014;
Rod íguez-Mo gado e al. 2015b; O s e al. 2017). This is a
consequence o he ac ha in his ype o BS, he amoun
o low molecula weigh p o eins (< 300Da) was g ea e
han ha ob ained wi h he BS o slaugh e house sludge.
The e o e, when he BS ob ained om he slaugh e house
sludge was applied o he soil, he mic oo ganisms quickly
assimila ed he low molecula weigh pep ides. Once hese
had been abso bed, he mic oo ganisms had o ob ain hei
ene gy om he high molecula weigh p o eins, exc e ing
ex acellula enzymes o deg ade said p o eins.
Tejada and Bení ez (2020) also obse ed ha he bio-
chemical ac i i y was highe in soils amended wi h o ganic
ma e wi h a highe pe cen age o low molecula weigh
pep ides. These au ho s also concluded ha he highe soil
mic obial s imula ion was possibly a consequence o a
highe abso p ion o low molecula weigh pep ides by he
mic oo ganisms.
Applying oxy luo en o non-amended soil caused a sig-
ni ican (p < 0.05) inhibi ion in he soil enzyma ic ac i i ies
du ing he expe imen (Tables2 and 3). A he end o he
expe imen and compa ed wi h he C ea men , dehyd oge-
nase, u ease, β-glucosidase, and phospha ase ac i i ies sig-
ni ican ly dec eased by 47.8%, 50.5%, 36.4%, and 45.5%,
espec i ely (Tables3 and 4).
Applying oxy luo en o non-pollu ed soil caused an
inhibi o y e ec on he soil biochemical ac i i y and mic o-
bial popula ion. These esul s a e in acco dance wi h Nadi-
je e al. (2013), Gómez e al. (2014), F anco-And eu e al.
(2016), Campos e al. (2019) and Wołejko e al. (2020), who
highligh ed he oxic e ec o oxy luo en on soil biochemi-
cal ac i i y.
The applica ion bo h o ganic compounds dec eased he
soil oxy luo en concen a ion (Fig.2). A he end o he
expe imen , he soil oxy luo en had dec eased 44.4% com-
pa ed o he concen a ion a day 5. Applying bo h o ganic
compounds o he pollu ed soil caused a signi ican dec ease
(p < 0.05) in he soil oxy luo en concen a ion. Compa ed
wi h he C + Ox ea men , he oxy luo en concen a ion had
dec eased by 33.3% in he C + Ox + SS ea men and by
60% in he C + Ox + BS ea men .
Gómez e al. (2014) and Rod íguez-Mo gado e al.
(2014) obse ed a signi ican dec ease in he concen a-
ion o oxy luo en a e he applica ion o a ious o ganic
compounds o con amina ed soil. These au ho s obse ed
ha his dec ease was g ea e in soils amended wi h o ganic
ma e wi h a high con en o low molecula weigh p o-
eins, possibly due o he ac ha oxy luo en- ole an soil
Table 4 E olu ion o
β-glucosidase and phospha ase
ac i i ies (mean ± s anda d
e o , n = 3) in soils amended
wi h slaugh e house sludge
(SS) and hyd olyza e
slaugh e house sludge (BS) and
wi h oxy luo en du ing he
expe imen al pe iod
Columns ollowed by he same le e (s) a e no signi ican ly di e en (p > 0.05)
PNP p-ni ophenol
Incuba ion days
5 10 20 35 55 90
β-glucosidase ac i i y (mmol PNP g−1 h−1)
C 1.4b ± 0.2 1.3b ± 0.2 1.3b ± 0.1 1.3b ± 0.2 1.2b ± 0.3 1.1b ± 0.1
C + SS 2.7c ± 0.8 2.9c ± 0.9 3.2c ± 1.2 3.8c ± 0.8 4.4cd ± 1.0 5.2d ± 1.2
C + BS 8.4d ± 1.8 5.9c ± 1.1 3.1c ± 0.6 2.4c ± 0.4 3.0c ± 0.5 3.5c ± 0.8
C + Ox 0.72a ± 0.09 0.79a ± 0.11 0.75a ± 0.08 0.76a ± 0.08 0.74a ± 0.12 0.70a ± 0.14
C + Ox + SS 2.3c ± 0.8 2.2c ± 0.4 2.5c ± 0.2 2.6c ± 0.7 2.9c ± 0.3 3.1c ± 0.8
C + Ox + BS 5.8c ± 0.4 4.1c ± 1.3 2.7c ± 0.3 1.7b ± 0.3 1.9bc ± 0.7 2.1c ± 0.5
Phospha ase ac i i y (µmol PNP g−1 h−1)
C 3.0b ± 1.0 3.3b ± 0.9 3.4b ± 1.2 3.4b ± 1.2 3.2b ± 1.1 3.3b ± 0.9
C + SS 4.9b ± 1.4 5.4b ± 1.7 6.2c ± 1.0 7.5c ± 1.8 8.6c ± 1.4 10.3d ± 2.1
C + BS 20.4d ± 3.1 11.5d ± 2.2 12.7d ± 1.4 7.2c ± 1.8 7.8c ± 1.1 8.2c ± 1.5
C + Ox 1.7a ± 0.4 1.9a ± 0.3 1.8a ± 0.4 1.9a ± 0.2 1.8a ± 0.3 1.8a ± 0.3
C + Ox + SS 4.4b ± 1.1 4.7b ± 1.5 5.2b ± 1.3 6.1c ± 1.0 6.8c ± 1.2 7.2c ± 1.8
C + Ox + BS 15.8d ± 2.0 10.4d ± 2.4 6.4c ± 1.8 4.2b ± 1.4 4.2b ± 1.2 4.6b ± 1.0
729In e na ional Jou nal o En i onmen al Resea ch (2021) 15:723–731
1 3
mic oo ganisms abso b hese pep ides mo e easily, a o ing
hei p oli e a ion in he soil and inc easing he deg ada ion
o said he bicide in soil.
This dec ease in he soil oxy luo en concen a ion caused
a dec ease in he enzyma ic ac i i ies inhibi ion shown in he
C + Ox ea men (Tables3 and 4). Also, he chemical com-
posi ion o bo h o ganic was es in luenced his ac ion di e -
en ly. Fo example, a he end o he expe imen al pe iod and
compa ed wi h he C + Ox ea men , dehyd ogenase ac i i y
had inc eased by 87.7% and 70.7% in he C + Ox + SS and
C + Ox + BS ea men s. U ease ac i i y inc eased by 79.1%
and 72.3% in he C + Ox + SS and C + Ox + BS ea men s.
β-glucosidase ac i i y had inc eased by 77.4% and 66.7% in
he C + Ox + SS and C + Ox + BS ea men s, espec i ely.
Phospha ase ac i i y inc eased by 75% and 60.9% in he
C + Ox + SS and C + Ox + BS ea men s.
The oxy luo en deg ada ion was highe in he BS-
amended soil han wi h SS. The highe pe cen age o low
molecula weigh p o eins (< 300Da) in he BS enabled
he he bicide- ole an mic oo ganisms o he said pep ides
mo e quickly. This s imula ed he mic obial popula ion and
consequen ly led o a g ea e deg ada ion o he he bicide.
The high pe cen age o high molecula weigh p o ein in
SS esul s in a lowe s imula ion in he he bicide- ole an
mic obial popula ion. Consequen ly, o e ime oxy luo en
deg ada ion is slowe han when SS is applied.
Applying he he bicide o non-o ganic amended soil
did no change he mic oo ganisms popula ion du ing he
expe imen al pe iod (Table5). Simila esul s we e ound
by Rod íguez-Mo gado e al. (2014) and Gómez e al.
(2014) in a soil wi h simila physicochemical cha ac e is-
ics and con amina ed wi h he same dose o oxy luo en
du ing a pe iod o 120days.
The applica ion o o ganic ma e o he soil caused an
inc ease in o al bac e ial PLFA and o al ungal PLFA
popula ion. Tian e al. (2017) and Zheng e al. (2021) also
Fig. 2 E olu ion o oxy luo en
(mean ± s anda d e o , n = 3)
in soils du ing he expe imen al
pe iod. Columns ollowed by
he same le e (s) a e no signi i-
can ly di e en (p > 0.05)
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
51020355
59
0
gkgm(ne oul yxO -1)
C+Ox C+Ox+SSC+Ox+BS
aa
aa
a
a
a
a
aa
ab b
ab
ab bbb
c
Table 5 E olu ion o bac e ial
G am+, bac e ial G am−,
o al bac e ial and ungal
PLFAs (nmol g−1), du ing he
expe imen al pe iod
Da a a e he means o h ee samples. Columns (mean ± S.E.) ollowed by he same le e (s) a e no signi i-
can ly di e en (p > 0.05)
T ea men Incuba ion days bac e ial G am+bac e ial G am−To al bac e ial PLFA Fungal PLFA
C 5days 28.1a ± 2.4 18.6a ± 1.8 47.7a ± 3.9 3.1a ± 1.1
90days 28.9a ± 2.0 19.5a ± 2.2 48.4a ± 4.4 2.8a ± 0.9
C + SS 5days 31.4a ± 2.5 24.4a ± 2.0 55.8a ± 4.3 3.8a ± 1.1
90days 49.9b ± 3.1 50.2b ± 2.7 100.1b ± 5.5 5.2b ± 1.2
C + BS 5days 50.2b ± 2.9 30.6ab ± 3.1 80.8b ± 6.3 3.7a ± 1.2
90days 50.0b ± 3.6 38.9b ± 2.2 88.9b ± 5.6 4.0a ± 1.7
C + Ox 5days 29.9a ± 1.3 23.5a ± 1.6 53.4a ± 2.7 3.6a ± 1.1
90days 27.3a ± 2.6 22.9a ± 1.2 50.2a ± 3.6 3.2a ± 0.8
C + Ox + SS 5days 29.8a ± 2.9 25.7a ± 2.6 55.5a ± 5.6 4.0a ± 1.7
90days 47.0b ± 1.6 49.1bc ± 3.3 96.4b ± 4.7 4.8ab ± 1.5
C + Ox + BS 5days 49.3b ± 2.7 30.4ab ± 2.4 79.7ab ± 4.8 4.0a ± 1.0
90days 46.7b ± 2.9 33.8b ± 1.7 80.5b ± 4.5 3.8a ± 1.2
730 In e na ional Jou nal o En i onmen al Resea ch (2021) 15:723–731
1 3
ound an inc ease in mic obial biodi e si y in soils wi h
a high con en o o ganic ma e . These au ho s sugges
ha he applica ion o o ganic ma e o he soil p o ides
subs a es ha can inc ease he o al abundance o PLFA.
When oxy luo en was applied o soils amended wi h
bo h o ganic compounds, he bac e ia and ungi popula-
ion was no di e en om ha obse ed o C + SS and
C + BS ea men s. This ac is possibly due o he ac ha
oxy luo en did no change he mic obial biodi e si y o
he soil, as p e iously men ioned.
Conclusions
Acco ding o he au ho s' knowledge, he main no el y o his
manusc ip is he i s s udy in which bio emedia ion es s ha e
been ca ied ou on soils pollu ed by he oxy luo en he bicide
using slaugh e house sludge, bo h concen a ed and in he o m
o bios imulan s a e subjec ing said sludge concen a ed o
an enzyma ic hyd olysis p ocess. The esul s ob ained in his
expe imen indica ed ha slaugh e house sludge dec eased
he inhibi o y e ec o he oxy luo en on he soil’s biological
p ope ies. Consequen ly, slaugh e house sludge could be con-
side ed as being e y use ul in bio emedying oxy luo en-pol-
lu ed soils. Howe e , he g ea es bio emedia ion e ec s we e
ob ained when he slaugh e house sludge was ans o med in o
a bios imulan by enzyma ic p ocesses ich in low molecula
weigh p o eins. These p o eins a e easily assimila ed by oxic-
ole an soil mic oo ganisms which accele a ed he deg ada-
ion o he he bicide in soil.
Howe e , he bio emedia ion e ec o slaugh e house
sludge should be s udied u he . The ype o con aminan
in he soil, as well he soil p ope ies, a e cha ac e is ics
o be conside ed o u u e s udies o be e unde s and he
e ec o hese o ganic was es on he bio emedia ion o pol-
lu ed soils.
Acknowledgemen s This wo k was suppo ed by he Minis e io de
Ciencia, Inno ación y Uni e sidades (Spain), Plan Nacional I+D+I
wi h e e ence RTI2018-097425-B-100, Jun a de Andalucia (Conse-
je ía de Economía y Educación), P oyec os I+D+i FEDER Andalucía
2014-2020, wi h e e ence US-1263885 and Comisión Eu opea, Ho i-
zon e 2020 wi h e e ence 3052/0048.
Funding Open Access unding p o ided hanks o he CRUE-CSIC
ag eemen wi h Sp inge Na u e.
Decla a ions
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