Subscriber access provided by The University of Texas at El Paso (UTEP)
Environmental Measurements Methods
Speciation of phosphorus zinc and copper in soil and water dispersible colloid affected by a long-term application of swine manure compost Kosuke Yamamoto, Yohey Hashimoto, Jihoon Kang, and Kazuki Kobayashi Environ. Sci. Technol., Just Accepted Manuscript • DOI: 10.1021/acs.est.8b02823 • Publication Date (Web): 17 Oct 2018 Downloaded from http://pubs.acs.org on October 22, 2018
Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.
is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.
Page 1 of 24
Environmental Science & Technology
1 2
Speciation of phosphorus zinc and copper in soil and water dispersible colloid
3
affected by a long-term application of swine manure compost
4 5 6
Kosuke Yamamoto1), Yohey Hashimoto1)*, Jihoon Kang2), and Kazuki Kobayashi1)
7
1)Tokyo University of Agriculture and Technology
8
2) University of Texas Rio Grande Valley
9
*corresponding author:
[email protected] 10
1 ACS Paragon Plus Environment
Environmental Science & Technology
Page 2 of 24
11 12
Abstract
13
The objective of this study was to investigate the concentration and chemical species of Zn,
14
Cu and P in the bulk soil and water dispersible colloid (WDC) fraction collected from a field
15
where swine manure (SM) compost has been continually applied for 23 years. A filtration
16
and ultracentrifugation process was used to separate and collect WDC (20–1000 nm) from
17
the soil. The continual application of SM increased soil P from 1.6 to 4.5 g kg-1, Zn from 109
18
to 224 mg kg-1 and Cu from 87 to 95 mg kg-1 for 23 years. The continual SM compost
19
application also enhanced the formation of soil WDC in which Zn (215 mg kg-1) and Cu (62
20
mg kg-1) were highly accumulated and P (25 g kg-1) was greater than the bulk soil.
21
According to the result of X-ray absorption spectroscopy (XAS), the continual application of
22
SM compost increased P associated with Fe hydroxides in the soil and WDC fraction. Iron
23
K-edge XAS revealed the dominance of goethite and ferrihydrite in the WDC fraction,
24
suggesting that P were bound to these (oxy)hydroxides. Copper K-edge XAS determined
25
the dominance of Cu(II) associated with humus in the soil and WDC fraction. For Zn
26
species in the SM compost applied soil, hopeite and Zn associated with humus were
27
accumulated in the bulk soil, whereas Zn associated with humus was the primary species in
28
the WDC fraction. Our study suggests that the formation of organic complexes in the WDC
29
fraction could enhance the mobility of Zn and Cu as the repeated application of SM
30
compost continues.
31 32
2 ACS Paragon Plus Environment
Page 3 of 24
33
Environmental Science & Technology
Introduction
34
Accumulation of phosphorus (P) and heavy metals of zinc (Zn) and copper (Cu) is a
35
common issue in soils receiving a large amount of swine manure (SM) and in farms with pig
36
production. Among the various types of livestock, SM or pig slurry contains relatively high
37
levels of Zn and Cu [1] due to the extensive use as veterinary medicinal products in pig
38
production [2]. Therefore, the continual application of SM in the farmland results in the
39
elevation of these elements in soils. Jensen et al. (2018)[2] reviewed the studies of
40
long-term field trial of swine manure applications and found that the annual loading rate of
41
Zn increases linearly to the annual accumulation of Zn in soils with an accumulation rate of
42
0.96 mg kg-1 per year in Denmark. Another monitoring study on pig-slurry applied soils in
43
the entire country of Denmark reported that 45% of all soil samples collected in the entire
44
country exceeded the predicted no-effect concentrations of Zn for soil organisms [3]. The
45
accumulation of Zn in soils receiving manure from piglet production farms may be
46
vulnerable to leaching loss of Zn, particularly in sandy soils [2].
47
The mobility and potential bioavailability of elements in soils depend on their
48
oxidation states and chemical species. According to previous studies using
49
synchrotoron-based X-ray absorption spectroscopy (XAFS), chemical species of elements
50
have been determined in SM and pig slurry mainly as struvite [4] for P, hopeite [4], Zn
51
phosphate [5] and ZnS [6] for Zn and Cu associated with organic matter [5] for Cu. It is
52
largely unknown how the chemical species of elements, particularly Zn and Cu in SM will
53
have been altered in the soil for a decade or even longer time span. Formentini et al. (2017)
54
[6] investigated Zn species in the soil applied continually with pig slurry for 11 years and
55
found that ZnS abundant in pig slurry was not detected in the soil but had been transformed
56
and accumulated as Zn associated with organic matter. A comprehensive study focusing on
57
P, Zn and Cu in SM applied soils is essential because high levels of soil Zn and Cu
58
detrimentally affect activity of phosphatases [7] that may affect P species derived from SM
59
in the long term. Phosphorus, Zn and Cu in soils are interacted each other in their chemical
60
species, eventually impacting mobility and potential availability to biota.
61
Water-dispersible colloid (WDC) being representative of readily mobile colloids with
62
a size range of 1-1000 nm plays a critical role in transport of elements in soils. Previous
63
studies observed a drastic increase of Zn, Cu and P transport in response to the increase of
64
colloidal transport [8, 9]. A notable accumulation of P and Zn was found in the WDC fraction
65
of soil and SM compost, compared with those bulk samples [4, 10]. With the use of
66
synchrotron-based XAFS spectroscopy, these studies revealed the contrasting differences
67
in chemical species of P and Zn between bulk soil and WDC phases, suggesting the
68
relevance of WDC fraction for elucidating mobility and potential bioavailability of elements 3 ACS Paragon Plus Environment
Environmental Science & Technology
69
in soils. Despite the importance of WDC in transport and bioavailability of elements,
70
previous studies have mainly focused on the bulk soil, particulate and dissolved fractions
71
(operationally defined as a
