IJERD – International Journal of Environmental and Rural Development (2021) 12-1

Research article
erd

Evaluation of Site Contamination from Storage of Fertilizer
I7d
BARRY NOLLER*eThe University of Queensland, St Lucia, Queensland, Australian
Email: b.noller@.uq.edu.aut
Received 14 January 2021

Accepted 18 May 2021 (*Corresponding Author)
4.
Abstract Australia has extensive agricultural
production of crops and livestock production.
Regular fertilizer application maintains
7 production rates of grain crops. Large quantities ofphosphorus-based fertilizers are produced
from phosphate rock by sulfuric acid extraction at2

designated production works at coastal locations and transported by train to distribution points
in selected agricultural areas. Bulk fertilizer
is stored in large sheds adjacent to railway linesw
and large or small trucks then makeo deliveries to farms. When such sites are disused orabandoned, contaminated soil may remainfrom fertilizer constituents. Occasionally fertilizerr
storage sites may have experience accidental
contamination from railway engine or truckdhydrocarbons. The objective of this study
istoexamine
the extent of fertilizer contamination ats
agricultural storage sites, identify environmental risks associated with the handling practices ofstorage sites, and distinguish from other contamination from transport vehicles. Soil samples
were collected at two locations using a grid-base sampling program to identify contaminants.
Following preparation soils were analysed for phosphorus, sulfate, sulfur, petroleumhydrocarbons (aliphatic and aromatic), heavy metals and pesticides using standard procedures.
A ‘within a target area’ was used to assess contamination levels by comparing the 95% Upper
Confidence Limit (UCL) of the average concentration of each analyte of concern against
respective ‘contamination’ criteria for industrial sites; exceedance of the 95% UCL against site
criteria identified contamination. Statistical analysis of the data for different analytes in soil at
fertilizer storage sites showed the relationship between contaminant levels and dispersion overrespective sites and extent of contamination from fertilizer handling activity and other vehiclerelated site contamination. In conclusion accurate estimation of contamination of sites can beprovided using the grid-base sampling approach and 95% Upper Confidence Limit (UCL)
criteria to distinguished transport vehicle-related contamination from phosphate-based fertilizer
on site.
Keywords fertilizer storage, transport vehicles, contamination, risk management

INTRODUCTION
Australia has extensive agricultural production of crops and livestock. Regular fertilizer application has
maintained production rates over many years (Fitzpatrick, 1968). Phosphorus-based fertilizers areproduced by sulfuric acid extraction at Australian coastal production works and transported by train todistribution points. Bulk fertilizer is stored in large sheds adjacent to railway lines and large or small
trucks then deliver to farms. The storage sheds usually have bare soil floors and over periods ofdecades fertilizer levels can build up. The disused or abandoned sites may leave soil contaminated withfertilizer phosphate, sulfate and sometimes sulfur (FMA, 1998). Occasionally fertilizer storage sites
have experienced contamination from railway engine derailment or truck hydrocarbons (NSW EPA,1994). The Australian National Environmental Protection Measure (NEPM) soil contamination
guidelines are risk-based Health and Ecological criteria (Noller, 2020) and some guidelines may be
applicable for assessing fertilizer contamination.

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IJERD – International Journal of Environmental and Rural Development (2021) 12-1

OBJECTIVE
The objective of this study is to examine the extent of fertilizer contamination from phosphate, sulfate
and sometimes sulfur at agricultural storage sites, identify environmental risks associated with thehandling practices of storage sites, and distinguish from other contamination due to transport vehicles.
METHODOLOGY
Soil samples were collected using a grid-base sampling program to identify analytes of concern (NSWEPA, 1995) at two comparative fertilizer storage sites; one location (A) experienced contamination due
to a rail derailment following fertilizer storage ten years earlier and another location (B) was used for
fertilizer only storage for several decades (Noller, unpublished data). Following preparation, soils wereanalysed by Queensland Health Scientific Services laboratory, Coopers Plains, Queensland forphosphorus, sulfate, sulfur, petroleum hydrocarbons (aliphatic and aromatic), heavy metals andpesticides using standard procedures (ANZECC, 1992; NEPM, 1999; NSW EPA, 1994; NSW EPA,1995).
The criteria from the NSW EPA (1998) Guidelines for the NSW Site Auditing Scheme were used,
together with the assessment criteria of the Australian National Environmental Forum health-based soil
investigation Levels for Soil and Groundwater NEPM (1999) at industrial sites. A ‘within a target area’
statistical evaluation was used to assess contamination levels by comparing the 95% Upper Confidence
Limit (UCL) of the average concentration of each analyte against respective ‘contamination’ criteriafor industrial sites; exceedance of 95% UCL against site criteria identified contamination using theassessment criteria of the NSW EPA Sampling Design guidelines (NSW EPA, 1995). “Hotspots” could
be identified when analytical results from individual sites were 250% of the relevant criteria value, andwhen the standard deviation of data was <50% of the criteria.
The 95% upper confidence limit (UCL) of the arithmetic average concentration is calculated usingEq. (1) (NSW EPA, 1995) as follows:
UCL average = x̄ + tα,n-1 x sd/√n(1)UCL average = Upper confidence limit of the arithmetic average concentration of the sampling area atthe 1-α confidence level.
α = The probability that the ‘true’ average concentration of the sampling area might exceed the UCL
average determined by Eq. (1).
n = Number of sample measurements.
n-1 = Ddegrees of freedomx̄ = Arithmetic average of all sample measurements.
tα,n-1 = The test statistic at an α level of significance and degrees of freedom of n-1 obtained from tableof values of Student’s t.
sd = Standard deviation of the sample measurements.
RESULTS AND DISCUSSIONTable 1 gives results for soil sulfate, total phosphorus and elemental sulfur concentrations at the two
fertilizer storage Locations (A and B). Both show extensive soil contamination, compared withcontamination criteria, from sulfate, phosphorus and sulfur (B only) with higher concentrations
observed at Location B due to extensive use over several years. Such contamination is quite different
to low level contamination of agricultural soils (Noller, 2020), but significant over long-term
accumulation in soil (Weissengruber et al., 2018). Comparison of the statistical evaluations using the95% Upper Confidence Limit (UCL) of average concentration of each constituent (NSW EPA, 1995)Ⓒ ISERD56

IJERD – International Journal of Environmental and Rural Development (2021) 12-1and exceedance of 95% UCL against the respective contamination criteria against site criteria(ANZECC, 1992; NEPM, 1999) enabled the following features of ‘hotspots’ to be identified:
••
•
•
•

Location A Sulfate. The difference of samples below the contamination criteria from allsamples showed that 7 sites are contaminated and indicated the extent of the ‘hotspot’ forsulfate.
Location A Total phosphorus. The difference of samples below the contamination criteria fromall samples showed that 13 sites are contaminated and indicated the extent of the ‘hotspot’ fortotal phosphorus and was more extensive than for sulfate.
Location B Sulfate. The difference of samples below the contamination criteria from all
samples showed that 7 sites are contaminated and indicated the extent of the ‘hotspot’ forsulfate.
Location B Total phosphorus. The difference of samples below the contamination criteria fromall samples showed that all 10 sites are contaminated and indicated the extent of the ‘hotspot’
for total phosphorus was also more extensive than for sulfate.
Location B Sulfur. The difference of samples below the contamination criteria from all
samples showed that 2 sites are contaminated and indicated the extent of the ‘hotspot’ forsulfur, was much less than for sulfate.

Table 1 Soil sulfate, total phosphorus and elemental sulfur concentrations at fertilizer sites
Test

SulfateTotal phosphorus
Elemental sulfur
as S (mg/kg)
as P (mg/kg)
as S (mg/kg)
A. Once only storage site (600 m2) followed by train derailment contamination of soil
Number of samples (n-all)
2020
Mean
4509
6132
Range
61-33400
130-25200
SD84586935
Students tα=0.05
1.729
1.729
95% UCL mean
1239
9850
Contamination criteria
2000a2000a
Number of samples
137(n<Contamination criteria)
Mean
527
926
Range
61-1600
130-1700
SD532
631
Students tα=0.05
1.782
1. 943
95% UCL mean
792
1389
Contamination criteria
2000a2000b
B. Storage site (5800 m2 used continuously for 40 y with only fertilizer contamination
Number of samples (n-all)
101010
Mean
28542
10470
3615
Range
520-100100
2400-22700
100-32300
SD33124
7277
10087
Students tα=0.05
1.833
1.833
1.833
95% UCL mean
47756
14691
9466
Contamination criteria
2000a2000b600b
Number of samples
308(n<Contamination criteria)
Mean
11732
225
Range
520-1600
100-500
SD
575
183
Students tα=0.05
2. 353
1. 8603
95% UCL mean
1954345
Contamination criteria
2000a600b
Source: a. ANZECC (1992) and b. NEPM (1999)Ⓒ ISERD

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IJERD – International Journal of Environmental and Rural Development (2021) 12-1

Table 2 Soil sulfate, total phosphorus, cadmium, lead and zinc concentrations at 9 sites,
Location A
Site A(surface 0cm)

Sulfate-S(mg/kg)

Cadmium(mg/kg)

Lead(mg/kg)

Zinc(mg/kg)

33,4005,600
120
19,000
360
160
930
1,200
250

Total
phosphorus-P(mg/kg)
20,800
10,200400
25,200
6,300
4,100
8,600
2,200
1,700

Site 1Site 2Site 3Site 4Site 5Site 6Site 7Site 8Site 9Contamination
criteria

9.7
2.2
<145
4.3
37.7
1.3
1.3

98
43
25790
62
3678
34400

170
160
32
460
220
130220110
240

2,000a2,000b

100b

1500b

35,000b

Source a. ANZECC (1992) and b. NEPM (1999)

Table 3 Soil total petroleum hydrocarbon, polynuclear aromatic hydrocarbons, benzo(a)pyrene,
and organo phosphorus pesticides concentrations at 9 sites, Location A
Site(surface0cm)
Site 1Site 2Site 3Site 4Site 5Site 6Site 7Site 8Site 9Contamination
criteria

Total
petroleumhydrocarbon(mg/kg)
142
194
48336
108
23
46
1367

PolyAromatichydrocarbons(total) (µg/kg)

Benzo(a)pyrene(µg/kg)

2,255
1,460
450
5,330
1,510
320830
255
1,370

2,255
1,460
450
5,330
1,510
320830255
1,370

Organophosphorus
pesticides(µg/kg)<10<10<10<10<10<10<10<10<1028,000b

100,000a

100,000a

10,000a

Source a. NEPM (1999) and b. NSW EPA (1994)

Tables 2 and 3 give comparative data for soil sulfate, total phosphorus, petroleum hydrocarbons(aliphatic and aromatic), benzo(a)pyrene, heavy metals (cadmium, lead and zinc), and organophosphorus pesticide concentrations for 9 sites at Location A with rail derailment contamination being
close to the railway line. Based on historical use of the agricultural storage site (Location A) forfertilizer, the type and concentration of contaminants found should be consistent with storage ofphosphorus-based fertilizers. Therefore the presence of cadmium, lead, zinc, total petroleumhydrocarbon (TPH) and BTEX (all at detection limit; benzene <0.5 mg/kg, toluene <0.5 mg/kg,
ethylbenzene <0.5 mg/kg and xylene <0.5 mg/kg), polyaromatic hydrocarbons (PAHs) comprisingbenzo(g,h,i)perylene, dibenz(a,h)anthracene, indeno(123c,d)pyrene, benzo(a)pyrene, benzo(b+k)
fluoranthene, chrysene, benz(a)anthracene, pyrene, fluoranthene, phenanthrene, fluorene,acenaphthalene, acenaphthene and naphthalene, benzo(a)pyrene itself as a key carcinogen from fuelcombustion, organo phosphorus pesticides, and are inferred collectively as not being consistent withthe presence of phosphate-based fertilizers; cadmium is also present in phosphate rock used in fertilizer
manufacture but is associated with zinc additives used in engine oils.
The data in Tables 2 and 3 is intended to show how fertilizer contamination can be displayed at
the same sites at Location A together with rail derailment contamination. Sulfate and total phosphorus
concentrations (Table 2) are consistent with the identification from Table 1 that some sites at LocationⒸ ISERD58

IJERD – International Journal of Environmental and Rural Development (2021) 12-1

A are contaminated with fertilizer by comparison against the contamination criteria and comprise‘hotspots’. None of the cadmium, lead, zinc, total petroleum hydrocarbon (TPH) and BTEX,
polyaromatic hydrocarbons (PAHs), benzo(a)pyrene or organo phosphorus pesticides (OCPs)
concentrations given in Tables 2 and 3 exceed respective contamination criteria and cannot be
described as ‘hotspots’ at Location A or as being environmentally significant. However, the associationof engine fuel and oil constituents with a rail engine derailment is clear.
CONCLUSION
Accurate estimation of contamination of sites has been demonstrated using the grid-base sampling
approach and 95% Upper Confidence Limit (UCL) criteria to distinguish transport vehicle-related
contamination from phosphorus-based fertilizer at two locations. Statistical analysis of the data fordifferent constituents in soil at the fertilizer storage sites showed the relationship between contaminantlevels and dispersion over respective sites (ANZECC, 1992; NEPM, 1999; NSW EPA, 1994; NSWEPA, 1995). Dispersion of constituents of phosphorus –based fertilizers can distinguish extent ofcontamination during the operational phases of fertilizer handling activity from other vehicle-related
contamination. “Hotspots” were identified when analytical results from individual sites were 250% of
the relevant criteria value, and when the standard deviation of the data set was <50% of the criteria.
ACKNOWLEDGEMENTS
Keith Halford provided assistance with the sampling study.
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FMA. 1998. Code of practice for the storage, handling and transportation of solid ammonium nitrate based
fertilisers. Fertiliser Manufacturers Association (FMA), Peterborough PE2 6XEUK, April 1998.
Fitzpatrick, E.N. 1968. The changing fertiliser industry. Journal of the Department of Agriculture, Western
Australia, Series 4, 9 (12), 554-555.
NEPM. 1999. Guideline on investigation levels for soil and groundwater. National Environment Protection
Measure for Assessment of Site Contamination. National Environment Protection Council, Canberra,Australia.
Noller, B.N. 2020. Environmental effects from contamination of agricultural soils via spraying and dust
application to crops and animals. IJERD International Journal of Environmental and Rural Development, 11(1), 68-73.
NSW EPA. 1994. Guidelines for assessing service station sites. NSW Environment Protection Authority,Chatswood, NSW, Australia.
NSW EPA. 1995. Sampling design guidelines. NSW Environment Protection Authority, Chatswood, NSW,Australia.
NSW EPA. 1998. Guidelines for NSW site auditor scheme. NSW Environment Protection Authority, Chatswood,NSW, Australia.
Weissengruber, L., Moller, K., Puschenreiter, M. and Friedel, J.K. 2018. Long-term soil accumulation ofpotentially toxic elements and selected organic pollutants through application of recycled phosphorus
fertilizers for organic farming conditions. Nutrient Cycling in Agroecosystems, 110, 427-449.

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