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Detection, Occurrence and Fate of Emerging Contaminants in Agricultural Environments Daniel D. Snow1*, David A. Cassada2, Shannon L. Bartelt–Hunt3, Xu Li4, Yun Zhang5, Yuping Zhang5, Qi Yuan5 and J. Brett Sallach5

ABSTRACT:

A review of the literature published in

KEYWORDS: pharmaceuticals, steroid hormones,

2011 including 70 papers on topics ranging from analytical

analytical methods, water and wastewater, agricultural

methods, to occurrence and environmental fate of emerging

environment.

contaminants in agricultural environments is presented. This review is divided into the following sections: Introduction,

Analytical

Methods

for

doi: 10.2175/106143012X13407275694635

Emerging

Contaminants, Passive Samplers and Screening Methods, Steroids

in

Agricultural

Environments,

INTRODUCTION

Veterinary

Nutrients, sediments, and pesticides are well

Pharmaceuticals in Agricultural Environments, Antibiotic

known and extensively studied contaminants impacting

Resistance Genes, and Prions as Emerging Contaminants.

water quality in agricultural environments. These groups of contaminants concentrations

typically in

occur

surface

at

run–off

easily in

measured agricultural

watersheds. Nutrients, especially nitrogen, and pesticides

______________________________________________________ 1

Research Associate Professor and Laboratory Director, Nebraska Water Center, part of the Robert B. Dougherty Water for Food Institute, 202 Water Sciences Laboratory, University of Nebraska, Lincoln, NE 68583–0844; Tel. 402–472–7539; Fax. 402–472–9599; email: [email protected]

have also been shown to impact ground water quality in areas susceptible to contamination. Less well–known are

2

Chemist, Nebraska Water Center, part of the Robert B. Dougherty Water for Food Institute, 202 Water Sciences Laboratory, University of Nebraska–Lincoln, Lincoln, NE 68583–0844; Tel. 402–472–7539; Fax. 402–472–9599; email: [email protected]

environmental impacts of newer classes of contaminants such as pharmaceuticals, steroids, antibiotic–resistance

3

Associate Professor, Department of Civil Engineering, 203B Peter Kiewit Institute, University of Nebraska–Lincoln, Omaha, NE 68182–0178, Tel. (402) 554–3868; Fax. (402) 554–3288; email: [email protected]

genes and prion proteins. These “emerging” contaminants clearly have potential to enter the environment and cause

4

Assistant Professor, Department of Civil Engineering University of Nebraska–Lincoln 844 N. 16th St., N117 SEC Link, Lincoln, NE 68588–6105; [email protected]

known or suspected adverse ecological or human health effects. Release of these contaminants to the environment

5

Graduate Research Assistant, Department of Civil Engineering, University of Nebraska–Lincoln Department of Civil Engineering, Department of Civil Engineering University of Nebraska–Lincoln, 844 N. 16th St., N117 SEC Link, Lincoln, NE 68588–6105

has occurred for quite some time, but methods for their

764 Water Environment Research, Volume 84, Number 10—Copyright © 2012 Water Environment Federation

detection at environmentally–relevant concentrations have

hormones in animal manure or agricultural soil. The

only recently become available.

method consisted of two parts: inverse and integrated

Evaluating the environmental fate and effects of

clean–up

pressurized

liquid

extraction;

and

gas

emerging contaminants includes compounds such as

chromatography–tandem mass spectrometry (GC–MS/MS).

surfactants, antibiotics and other pharmaceuticals, steroid

In pressurized liquid extraction (PLE), the samples were

hormones and other endocrine–disrupting compounds

flushed with heptane to avoid the interference of undesired

(EDCs),

disinfection

matrix and then dealt with internal clean–up PLE to elute

byproducts, new pesticides and pesticide metabolites, and

the steroids. A two step solid phase clean–up (aminopropyl

naturally–occurring algal toxins. Detection of these

and silica gel) was then used to further purified the PLE

contaminants

(water,

extracts. There was a one hour derivatization before the

wastewater, soils and sediments) is particularly challenging

samples were analyzed with GC–MS/MS. The absolute

because of the low detection limits required, the complex

PLE recoveries in this study ranged from 67 to 107 % from

nature of the samples, and difficulty in separating these

0.5 g manure spiked with 50 ng. The development and

compounds from interferences. New extraction and clean–

implementation of a method for simultaneous detection of

up techniques, coupled with improvements in instrumental

five sulfonamides, three tetracyclines, and one macrolide

technologies provide the needed sensitivity and specificity

was accomplished by Pan et al. (2011). Using this method,

for accurate measurement.

126 samples from 21 concentrated animal feeding

fire

retardants,

in

sunscreens,

environmental

matrices

The objective of this paper is to review the

operations (CAFOs) were analyzed.

Concentrations

literature published in 2011 evaluating the detection, fate,

reached as high as 764.4 mg/kg (chlortetracycline) and the

and occurrence of emerging contaminants, with a particular

tetracyclines had detection frequencies between 84.9–

focus on emerging contaminants in agricultural systems.

96.8%, 0.8–51.6 % for sulfonamides, and 4.8% for the

Relevant contaminants are EDCs (particularly hormones

macrolide antibiotic. It was concluded that CAFOs manure

and

may act as a non–specific source of antibiotics in farmlands

anabolic

steroids),

antibiotics

and

other

pharmaceuticals associated with wastewater, antibiotic

and aquatic environments.

resistance genes in bacteria and prions. Studies on

Sixteen

compounds

including

antibiotics,

pesticides and flame retardants are not reviewed unless they

hormones, analgesics, stimulants, antiepileptics, and X–ray

were evaluated in the same study.

contrast media were analyzed from 31 water treatment

Analytical Methods for Emerging Contaminants

facilities in the study by Wang et al. (2011).

Pharmaceutical

detection limits (MDLs) were determined in reagent water

Hansen et al. (2011) developed a novel

and municipal tap water ranging from 0.1 to 9.9 ng/L.

Steroid Analysis.

Method

Hormone

and

analytical method for simultaneous detection of ten steroid

While most concentrations were below the MDL, caffeine


was detected at the highest concentration 224 ng/L. Wang

extraction

et al. (2011) also noted seasonal differences, with higher

cartridges resulted in detection limits of 3.0–5.4 ng/L for

concentrations in the summer than winter. Due to water

each analyte. Results from application of the method to

volume differences, the total loadings into receiving waters

samples from river water near wastewater treatment plants

were similar in both seasons.

(WWTP) are given.

parameters

using

Discovery

DSC–18Lt

Avbersek et al. (2011) combined trimethylsilyl

Lucci et al. (2011) describe a method for clean–

derivatization GC–MS analysis with the ER–Calux®

up and preconcentration of natural and synthetic estrogens

estrogenicity assay into a single protocol to determine

using molecular imprinted polymers (MIPs) as a selective

steroid estrogen concentrations and total estrogenic

solid phase extraction (SPE) medium. Recoveries of >85%

potential (E2 equivalents, EEQ) from the same sample

were obtained for natural estrogens while synthetic

extract. Optimization of the dual method required

estrogens had recoveries of >48%. Detection limits ranged

introduction of a solvent (ethyl acetate) compatible with

from 4.5 to 9.8 ng/L for spiked river and tap water samples.

each phase of analysis. Correlation of results obtained from

Comparisons of MIP results to those obtained using

spiked and unspiked waste water samples (effluent and

commercial C–18 SPE cartridges are discussed.

influent) using each method was given with r2 > 0.92.

Trinh et al. (2011)

describe a derivatization

Detection limits of 0.68 ng(EEQ)/L were obtained for the

method for the gas chromatography mass spectrometry

estrogenicity assay and 0.1–1.4 ng/L for GC–MS.

(GC/MS) analysis of estrogens and androgens in aqueous

Iparraguirre et al. (2011) report on a method

samples. Isotope labelled internal standards were used for

using stir bar solid phase extraction coupled with in–tube

8 of the 12 analytes which provided improved accuracy for

derivatization and thermal desorption GC–MS for analysis

the analysis. Detection limits of 1–5 ng/L were obtained in

of endocrine disruptor analytes in estuaries and wastewater

various aqueous matrices. Results from application of the

effluents and influents. Detection limits of 0.8–74 ng/L

method to surface waters and effluent wastewaters are

were obtained from extraction of 100 mL water samples.

discussed.

Results from optimization studies of various extraction and derivatization

parameters

are

given

along

Zhang et al. (2011) report on the use of a mixed–

with

mode

cation

exchange

(MCX)

SPE

method

for

environmental results obtained from effluent and influent

determination of 31 endrocrine–disruptor compounds in

wastewater using the optimized analytical method.

surface waters with optimized detection by LC–MS/MS in

A capillary liquid chromatography–tandem mass

positive and negative electrospray modes. Detection limits

spectrometry (cLC–MS–MS) method has been reported by

obtained from 1000 mL samples were 0.2–1.9 ng/L for all

Kozlik et al. (2011) for the separation and detection of

analytes with recoveries of 84.4–103.0%.

Results are

estrogens in water samples. Optimization of solid phase


reported from application of the method to surface waters

water fortified with 40 mg/L sulfadiazine and provided

in Shanghai, China.

comparable results to samples analyzed by LC–MS/MS. Steroids in Agricultural Environments

A method for accessing estrogenic activity in surface waters and sediment has been reported by Zhao et

Occurrence and Fate of Steroid Hormones.

al. (2011) combining recombinant yeast estrogen screening

Bevacqua et al. (2011) compared the occurrence of steroid

with GC–MS in negative chemical ionization (NCI) mode.

hormones in municipal biosolids and poultry litter. The

Water samples were extracted using Oasis HLB SPE

analyzed steroids included estrone, 17β–estradiol, estriol,

cartridges and sequentially eluted with methanol and

17α–ethinylestradiol, E1–sulfate, E2–3–sulfate, E2–17–

dichloromethane. Sediment samples were ultrasonically

sulfate, testosterone, and progesterone. The results showed

extracted with ethyl acetate. Results obtained from river

that estrone and progesterone were detected at levels of 2.5

water indicated good correlation between the bioassay and

to 21.7 ng/g dry weight and 2.5 to 470 ng/g dry weight

chemical analysis (R2 > 0.91).

respectively in the samples of limed biosolids collected at a

Passive Samplers and Screening Methods

wastewater treatment plant over a four year period. The

Bartelt-Hunt

et

al.

(2011)

improved

the

average

concentrations

of

estrone,

E1–sulfate

and

application of polar organic chemical integrative samplers

progesterone in poultry litter collected from 12 mid–

(POCIS) for steroid detection in surface waters receiving

Atlantic farms were 41.4, 19.2, and 63.4 ng/g dry weight,

wastewater treatment effluent and agricultural runoff by

respectively.

determining the chemical–specific uptake rates of 16

Gall et al. (2011) analyzed nine steroid hormones

steroids and metabolites, including 11 compounds for

in samples collected from subsurface tile drains and a

which uptake rates were not previously available. The

receiving ditch at a working farm in the Midwestern United

uptake rates of these steroidal compounds were determined

States where animal wastes are applied to agricultural

at 25oC under flowing conditions ranging from 0.19 to 0.65

fields. More than 64% of the samples collected at each

L/d. Uptake rates for pharmaceuticals were also reported.

sampling site contained hormones, among which estrone

Almeida et al. (2011) describe a method for rapid automated

in–situ

monitoring

of

relatively

was detected the most frequently and estriol the least. The

high

synthetic androgens were detected in < 15 % of samples,

concentrations of sulfadiazine used in aquaculture with

which was less frequently than natural androgens

potentiometric sensor based on a tubular electrode and PVC

testosterone and androstendione. The highest concentration

membrane. The detection limit using the optimized flow

of synthetic androgens (168 ng/L) in subsurface tile drains

injection method with the sensor was estimated at 3 µM

was observed during a snowmelt period. In the receiving

(~750 µg/L) and allowed repeatable detection of surface

ditch, the highest concentrations of total estrogens and natural androgens were 87 ng/L and 52 ng/L respectively,


both of which were observed in June, the early

larger possibility that 17α–estradiol will leached from

development period of many aquatic species.

agricultural fields. Based on the results, it was deduced that

By exposing female fathead minnows to the

stereoselective sorption of these two isomers might be

sediment samples collected from three sites within two

associated with aromatic interactions and H–bonding,

agriculturally intense Nebraska watersheds (Bow Creek and

though the sorption appeared to be driven primarily by

the Elkhorn River), Sellin Jeffries et al. (2011) found that

hydrophobic forces.

the hepatic mRNA expression of two estrogen responsive

Bera et al. (2011) investigated the sorption of

genes, estrogen receptor α (ERα) and vitellogenin (Vtg)

17β–estradiol and testosterone in soil without and with

decreased significantly, which indicated the bioavailability

poultry litter. When 3H–estradiol and 14C–testosterone were

of some anti–estrogenic compounds present in the sediment

applied to the soil separately without poultry litter, the

or water matrix. Besides, the lipophilic extracts of the

sorption of estradiol to soil was stable from 2 to 24 h and

sediments were able to induce significant reductions in the

then decreased to 72 h, while testosterone in soil increased

estrogenic reporter activity. Correspondingly, various

from 2 to 48 h and then kept relatively constant thereafter.

steroid hormones were detected in the sediments, including

This difference may result from different transformation

those applied very often in the local beef cattle feedlots (i.e.

rates of the two hormones with different solid–phase

β–trenbolone, α–zearalanol and α–zearalenol). These

affinity. The maximum sorption coefficients (Kd) for the

results suggest that agriculturally utilized steroid hormones

two steroids were 20.2 and 19.6 mL•g–1 respectively.

are able to enter the surrounding watersheds and potentially

When applied together, Kd of 14C–testosterone decreased to

result in the defeminization of aquatic organisms. It is

12.5 mL•g–1 and

possible that the sediment acts as a potential source of anti–

speculated that the competition between the two steroids

estrogenic compounds.

and their metabolites for sorption sites might be responsible

3

H–estradiol 7.4 mL•g–1. It was

Mashtare et al. (2011) investigated the sorption of

for the decrease of sorption. Besides, it was also found that

17α–estradiol and 17β–estradiol on seven surface soils of

poultry litter had different impact on the sorption of the two

various

of

steroids to soil: estradiol sorption increased but testosterone

biodegradation. The results showed that the sorption of

decreased. The reason that resulted in this difference might

estradiol was well correlated to the organic carbon (OC)

be poultry litter slowed down the transformation of the

content of soils, and the average log organic carbon–

parent hormones.

soil

properties,

avoiding

the

impact

normalized distribution coefficients (log Koc, L•kgoc–1)

Mansell et al. (2011) investigated the release and

were 2.97±0.13 for 17α–estradiol and 3.14±0.16 for 17β–

transport of six endogenous steroids from a steer feedlot

estradiol. Typically, the sorption of 17α–estradiol was on

during simulated storm events. Both soil and runoff samples were collected and analyzed for 17α–estradiol,

average 50% less than 17β–estradiol, which indicated


17β–estradiol, estrone, testosterone, androstenedione, and

Rhodobacter, among which Sphingomonas taking up over

progesterone. It was found that only 17α–estradiol,

46% of the total DNA sequence was the dominant species

testosterone, and progesterone were present in fresh

and Rhodobacter was the second most abundant. Besides,

manure,

and

the mineralization pathway of the testosterone was

androstenedione appeared in the surficial soil after two

elucidated based on the degradation products analysis. The

weeks. 17α–estradiol concentration in the surficial soil

products

decreased by about 25%, meanwhile an equivalent of

androstadienedione, and dehydrotestosterone for sure, as

estrone and 17β–estradiol increased. For an additional

well

aging period of 7 days for the soils, the concentrations of

hydroxyandrostadienedione

estrogen and testosterone didn’t change significantly, while

secoandrosta–1,3,5

androstenedione concentrations obviously decreased and

hydroxydehydrotestosterone

progesterone concentrations increased. After a simulated

androstenedione by inference. Within 8 days of incubation,

storm event, the estrogen concentrations in the soil

49–68% of the

remained almost the same, while the concentrations of

and the reaction followed pseudo–first– order reaction

androgens and progesterone decreased by approximately

kinetics with half–lives of 10–143 h.

however,

17β–estradiol,

estrone,

identified

as

included

9α–hydroxy–

androstenedione,

testosterone, or

9α–

3–hydroxy–9,10–

(10)–triene–9,17–dione, or

14

and

9α–

9α–hydroxy–

C–testosterone was mineralized to

14

CO2

85%. Except 17β–estradiol, the other five steroids in the

Khunjar et al. (2011) have evaluated the relative

runoff were present in both the filtered and particle–

roles of ammonia oxidizing and heterotrophic bacteria

associated phases to a level above thresholds for biological

during the transformation of 17α–ethinylestradiol. It was

responses. There was less 17α–estradiol and testosterone,

found that ammonia oxidizing bacteria was only able to

but more estrone, androstenedione, and progesterone

transform 17α–ethinylestradiol, whereas heterotrophs were

detected in the runoff from aged plots than from unaged

capable of mineralizing it as well as its metabolites

plots.

transformed by ammonia oxidizing bacteria. However, the Yang et al. (2011) revealed that Proteobacteria

transformation rate by ammonia oxidizing bacteria was five

played an important role in aerobic degradation and

times greater than that by heterotrophs. The removal of

mineralization of testosterone in manure treatment or land

17α–ethinylestradiol was significantly slowed down if

application. They enriched testosterone degrading culture

ammonia oxidizing bacteria were inhibited, which further

from swine manure by using testosterone as the sole carbon

proved its important role in transforming ethinylestradiol.

and energy source. Six genera of the bacteria were

Besides, two major metabolites were found in ammonia

identified from the enriched culture based on DNA

oxidizing, heterotrophic, and their mixed culture; one of

sequencing

them, sulfo–ethinylestradiol, was largely resistant to further

Comamonas,

results:

Acinetobacter,

Sphingomonas,

Brevundimonas,

Stenotrophomonas,

biodegradation.

and


Writer

et

al.

(2011)b

compared

the

Mao et al. (2011) provided an insight to an

biodegradation and attenuation of 17β–estradiol, estrone,

enzymatic reaction that played an important role in the

17α–ethynylestradiol in three different environmental

transformation

matrices: biofilm, sediment and water. The results showed

conditions. The kinetic behaviors of lignin peroxidase

that biofilm played an important role in the attenuation of

(LiP)–mediated reactions for estone, estradiol, estriol, and

steroidal compounds in surface waters due to both

ethinylestradiol weve investigated with the absence and

biodegradation and sorption processes. The sorption rates

presence of veratryl alcohol (VA), a chemical produced

to both biofilm and sediment was greater (185), which

significantly enhance the reaction efficiency. Then the

potentially resulted in accumulation in biofilm and

quantitative

sediment. In addition, 17β–estradiol was biodegraded more

equations were established by correlating the kinetic

effectively in sediment than in the biofilm and water

parameters with structural features of LiP/substrate binding

matrices. Biodegradation of 17α–ethynylestradiol by the

complexes. The result indicated that binding distance

sediment occurred at later time intervals (70 and 185 d) and

between a phenolic proton of substrate and δN of HIS47’s

was not observed in the biofilm or water matrices.

imidazole ring was very important in adjusting substrate

Another study by Writer et al. (2011a) focused on

of

steroid

structure

hormones

activity

under

relationship

natural

(QSAR)

reactivity toward LiP with and without VA.

the sorption of 17β–estradiol and 17α–ethynylestradiol to

Factors influencing steroid transformation.

biofilm colonized on artificial substrata in surface waters

Lee et al. (2011) evaluated the impacts of humic acid at

by batch experiment. It was found that the sorption was

different concentrations (0, 10, 30, 50 mg C/L) on the

linearly correlated with organic matter content, and the

biodegradation of 17β–estradiol in aqueous phase based on

dominant sorption mechanism might be hydrophobic

batch experiments. Besides 17β–estradiol, estrone was also

partition. The partition coefficients (Kom, L•kg–1) for the

analyzed for each sample and estrogenicity associated with

two steroids were 102.5–2.8 L•kg–1 and 102.5–2.9 L•kg–1,

17β–estradiol removal was estimated with E–screen

respectively. This suggested that steroids could readily sorb

bioassay. It was found that the biodegradation rate of 17β–

to and accumulate in biofilms, which was a potential

estradiol and the formation rate of estrone significantly

exposure pathway for organisms in higher trophic levels.

decreased with the increase of humic acid concentration,

Though various environmental conditions resulted in

while the increasing humic acid level resulted in the higher

differences in

sorption

the composition

of periphyton

and

of

17β–estradiol

from

6%

to

22%.

heterotrophic bacteria of the biofilm, they did not

Correspondingly, the solution without humic acid showed

significantly affect the sorptive properties of the biofilm.

the highest estrogenicity which represented the highest 17β–estradiol removal, and the presence of humic acid


showed slightly higher estrogenicity. Overall, 17β–estradiol

River and analyzed for 22 antibiotics and seasonal

biodegradation mainly accounted for its removal in

variances between June and December. Antibiotic classes

aqueous phase, and the biodegradation was enhanced with

included

the sorption significantly decreased at various HA

fluoroquinoles, sulfonamides, and trimethoprim. Jiang et

concentrations. In addition, the presence of nutrients

al. (2011) found that dominant species varied seasonally

enhanced the biodegradation of 17β–estradiol, which

and that veterinary antibiotics dominated in suburban

suggested that the level of nutrients in natural waters

sampling sites.

should be taken into account in estimating estrogenicity of

detected with frequencies ranging from 5.3 % to 100%.

environmental samples due to complex biodegradation and

chloramphenicols,

macrolids,

All but 4 of the 22 compounds were

Hoa et al. (2011)

sorption processes. Homklin

tetracyclines,

examined the detection of

antibiotics in commonly used in agricultural systems as et

al.

(2011)

evaluated

the

well as urban environments and correlated the results with

biotransformatoion of 17α–methyltestosterone (MT), an

the presence of antibiotic resistant bacteria in these

anabolic androgenic steroid, in sediment with different

environments.

electron acceptors. The results showed that the half–life of

sulfonamides and common macrolides.

MT under aerobic and sulfate–reducing conditions was 3.8

macrolides, including erythromycin (154–2246 ng/l) and

d and 5.3 d, respectively, and the androgenic activity could

clarithromycin (2.8–778 ng/l), were most common in city

eventually disappearance. Under methanogenic condition,

canal sites. Sulfamethazine (475–6662 ng/l) was dominant

the androgenic activity could persist 45 d or longer

in pig farm ponds and sulfamethoxazole (612–4330 ng/l)

although transformation of MT did occur. Besides, MT

was dominant in city canal and aquaculture sites.

The

transformed slowly under iron(III)–reducing condition and

study

but

was hardly transformed with nitrate as electron acceptors. It

concluded that antibiotic–resistant bacteria occurred not

was inferred that the methyl group at the C–17 position

only within contaminated sites but also less contaminated

might account for the hindrance of transformation of MT

sites.

under nitrate–reducing condition. As a result, MT and its metabolites

androgenicity

contamination

patterns,

The detection of 21 antibiotics from six different classes in coastal waters was investigated by Zou et al.

accumulate in the iron(III)–reducing, nitrate–reducing and

(2011). Water samples were taken from the Bahai Bay, six

methanogenic sediments.

contributing rivers, and three aquaculture breeding sites.

Pharmaceuticals

could

specific

They found

potentially

Veterinary

with

showed

In their study, they identified numerous

in

Agricultural

Zou et al. (2011) concluded that areas in the north Bahai

Environments

Bay region, characterized by high density human activity,

Fate and Occurrence. Jiang et al. (2011)

contributed to environmental exposure.

collected water samples from 19 sites along the Huangpu

The higher

concentrations in the river samples than bay samples


revealed the importance of river discharge as an antibiotic

handling a variety of waste sources including households,

source posing ecological risk to the bay.

livestock

Seventeen

common

human

and

veterinary

farms,

manufacturing.

hospitals, They

and

characterized

pharmaceutical the

dominant

antibiotics in four classes (fluoroquinolones, tetracycline,

pharmaceutical contaminant in the influent waste from the

sulfonamides, and macrolides) were investigated by Zhou

different sources. Antibiotics dominated the livestock farm

et al. (2011)in three rivers in northern China. The study

source. Concentrations detected in waste effluent was less

revealed higher concentrations in river sediment of one

consistent between sites and additional variability coming

river (Hai River) than the other two, with norfloxazin,

from sampling periods.

ofloxacin, ciprofloxacin, and oxytetracycline being the

Wei et al. (2011) investigated the prevalence of

most commonly observed at concentrations up to 5770,

ten veterinary antibiotics in animal wastewater and surface

1290, 653, and 652 ng/g, respectively. Sources of exposure

water around large–scale livestock and poultry farms in

were determined to be large cities, feedlots, and fish ponds.

Jiangsu Province of China. All ten compounds investigated

This data was strongly correlated with physicochemical

were detected in the animal wastewater, eight antibiotics

properties (TOC, texture, and pH) of the river sediment.

were detected in pond water, while nine of the ten were

This suggests that sediment properties are important factors

detected in animal farm–effluent and river water samples.

influencing the distribution of antibiotics in aquatic

The

environments.

sulfamethazine (75%), oxytetracycline (64%), tetracycline

The occurrence of human pharmaceuticals, disinfection

by–products

and

other

most

frequently

detected

compounds

were

(60%), sulfadiazine (55%), and sulfamethoxazole (51%).

wastewater

The highest concentrations of the compounds were found in

contaminants in irrigation water was investigated by

the animal wastewaters.

Calderan–Preciado et al. (2011). The use of reclaimed

specific antibiotics were related to animal species revealing

wastewater

a high spatial variation.

for

irrigation

is

becoming

increasingly

Detected concentrations of

important source for crop production, though may

The occurrence of veterinary pharmaceuticals in

inadvertently introduce contaminants to food crops.

lagoons and in groundwater adjacent to confined cattle and

Twenty–six

pharmaceuticals,

swine feeding operations was evaluated by Bartelt–Hunt et

pesticides, estrogens, antioxidants, and disinfection by–

al. (2011a). Pharmaceuticals detected in lagoons at cattle

products were detected in samples of wastewater, river

facilities

water receiving effluent and irrigation water.

sulfathiazole.

chemicals,

including

Occurrence and distribution of pharmaceuticals

detected

in waste treatment facilities was studied by Sim et al. (2011).

included

in

monensin,

erthyromycin,

and

Erthromycin and monensin were also groundwater

underlying

cattle

feeding

operations at concentrations ranging from 75%).

and sul2, which code for dihydropteroate synthases

The effects of manure and pH were examined by

insensitive to sulfonamides, were monitored 60 days after

Strauss et al. (2011), where they tested solute displacement

each manure application. Results show that the resistance

of sulfadimethoxine, sulfamethazine, and sulfamethoxazole

genes increased by up to 3 orders of magnitude in soil

at different pH (5, 6.5, 8.5) with and without manure. They

receiving SDZ–containing manure than in soils receiving

found that recovery of sulfonamides decreased with

SDZ–free manure. It was suggested that elevated sul1 and


sul2 levels in soil were due to the selective pressure exerted

chloramphenicol and tetracycline, 1 to >256 µg/mL for

by bioavailable SDZ in soil.

nalidixic acid and 12 to >256 µg/mL for penicillin. However, no significant correlation was found between

Meyer et al. (2011) compared run–off losses of

antimicrobial resistance and dairy farm age.

pesticides and pharmaceuticals, and steroid hormones in Ibuprofen,

Another study described the antibiotic resistance

sulfamethoxazole, diclofenac, and estrone were detected in

profiles of E. coli isolates from swine manure, lagoon

storm run–off and related to other water quality

effluent, and soils that received the lagoon effluent (Graves

measurements, though the locations of source areas could

et al. 2011). A total of 616 E. coli isolates were obtained

not be established.

from manure, lagoon and soil on a swine farm in North

two

small

watersheds

in

Luxemborg.

Carolina. 60.6% to 91.3% of the isolates harbored genes

Veach and Bernot (2011) report on a study of pharmaceutical levels in 2 streams in central Indiana with

coding

both

streptomycin/spectinomycin

agricultural

and

suburban

land

use.

Twelve

resistance

mechanism (aadA/strA

against and

strB),

pharmaceuticals were detected including acetaminophen,

tetracycline (tetA and tetB), and sulfonamide (sul1). The

caffeine, carbamazepine, cotinine, N,N–diethyl–meta–

authors concluded that the occurrence of specific antibiotic

toluamide

ibuprofen,

resistance genes (ARGs) varied with seasons as well as the

sulfamethoxazole,

environmental conditions of the locations on the swine

(DEET),

sulfadimethoxine, triclosan,

and

gemfibrozil,

sulfamethazine, trimethoprim.

Concentrations

farm.

of

pharmaceuticals were comparable and increased during the

To understand the environmental impact of

winter at both locations and decreased in spring and

antibiotic application in plant agriculture, Walsh and co–

summer. Pharmaceutical levels were not correlated with

workers developed multiplex quantitative PCR (qPCR)

nitrogen isotope analysis of sediment, though the δ15N of

assays for streptomycin (strA, strB, aadA and insertion

sediment was higher in the urban influenced watershed.

sequence IS1133) and tetracycline (tetB, tetM and tetW)

Correlation was sought between the antimicrobial

resistance genes and applied them on orchard soil samples

resistance profiles of Escherichia coli isolates and the age

(Walsh et al. 2011). Among these genes, strB, aadA, tetB

of dairy facilities (Jones et al. 2011). E. coli was isolated

and tetM were detected most frequently. After application

from the topsoil of 11 dairy farms with varying ages (0.5 –

of swine manure, the relative concentration of tetB and

24 years) and the minimum inhibitory concentrations

streptomycin resistance genes in soil decreased, while the

(MICs) of the isolates to antimicrobials were determined

quantity of tetM and tetW either remained at the same level

using E–test strips and gradient plate method. The MICs of

or increased. The occurrence of resistance to heavy metals and

the isolates ranged from 0.75 to >256 µg/mL for

antibiotics were reported for Pseudomonas isolates from


river water and agricultural soils irrigated with wastewater

methicillin resistance gene (mecA) in 71 phage DNA

and groundwater (Malik and Aleem 2011).

This study

samples from livestock fecal wastes/wastewater using

showed that the majority of the Pseudomonas isolates

qPCR. They reported that the abundance of ARGs in the

exhibited resistance to multiple heavy metals and

phage samples ranged from 103 to 104 copies/g of slurry or

antibiotics.

For example, among the 48 Pseudomonas

mL of wastewater for blaTEM, 102 to 103 copies/g or mL

isolates from wastewater–irrigated soil, 87.5% were

for blaCTX–M, and 101 to 103 copies/g or mL for mecA.

resistant to sulfadiazine, 79.1% resistant to both ampicillin

The authors suggested in addition to selective pressure due

and erythromycin, and 20.8% co–resistant to eight heavy

to environmental residue of antibiotics, the ARGs on

metals. In comparison, lower percentages of the isolates

bacteriophages could also contribute to the proliferation of

from groundwater–irrigated soil exhibited resistance to

antibiotic resistance in the environment.

heavy metals and antibiotics.

Munir and Xagoraraki studied the fate of ARGs

Torres–Cortes and co–workers identified and

(tetW, tetO, and sul1) in soil after land application of

characterized novel antibiotic resistance genes in soil

manure and biosolids at two experimental sites (Munir and

(Torres-Cortes et al. 2011).

A functional metagenomic

Xagoraraki 2011). The levels of ARGs in manure and

approach was used to search for novel resistance genes in

biosolids ranged from 108 to 1010 copies/g, much higher

three soil samples by constructing metagenomic libraries

than the background levels of 104–106 copies/g in

and isolating resistant clones. By using this approach, 11

untreated soil.

novel antibiotic resistance genes were identified: 3

and/or biosolids were land applied at the two sites, the

conferring resistance to ampicillin, 2 to gentamicin, 2 to

ARGs in soil appeared to increase at one site but not the

chloramphenicol, and 4 to trimethoprim.

This study

other. It was suggested that the differences of the fate of

indicates that soil bacteria are a reservoir of antibiotic

ARGs at the two sites might be affected by environmental

resistance genes.

conditions and soil types.

In addition, the authors found that a

Over a four–month period after manure

reductase belonging to the dihydrofolate reductase group

Lanthier and co–workers characterized the

conferred resistance to trimethoprim, demonstrating the

antibiotic resistance profile of enterococci species in an

advantage of functional metagenomics in discovering novel

agriculture intensive drainage basin (Lanthier et al. 2011).

antibiotic resistance functions of enzymes.

The authors isolated 1558 enterococci isolates from the

Bacteriophages could be an environmental vector

South Nation River watershed over a 3–year period, and

for the horizontal transfer of antibiotic resistance genes in

determined their virulence and antibiotic resistance using

the environment (Colomer-Lluch et al. 2011). Colomer–

PCR and culture methods, respectively. Results showed

Lluch and co–workers quantified two β–lactam antibiotics

that 28.5% of the isolates were resistant to lincomycin

resistance genes (blaTEM and blaCTX–M) and one

while less than 2% to ciprofloxacin and vancomycin, two


category I antibiotics.

The authors concluded that the

significant correlation was observed between quartz

chance of dispersion of antibiotic resistance via water borne

attachment and selected genes encoding attachment factors.

enterococci in an agricultural drainage basin is small.

Prions as Emerging Contaminants

Graham

led

a

study

to

investigate

the

The prion, or PrPSc, is believed to be the

contribution of various environmental pollutants (i.e.,

infectious agent responsible for prion diseases which are

antibiotic, heavy metals, and organic pollutants) to the

also called transmissible spongiform encephalopathies

emergence of antibiotic resistance in the environment

(TSEs). In recent years, prions have gained increasing

(Graham et al. 2011). The authors collected samples from

attention from the public as an emerging contaminant due

8 locations along the Almendares River in western Havana,

to its fast and facile spread among cervids (chronic wasting

Cuba, where industrial pollution widely exists but

disease, CWD), ovines (scrapie), and bovines (mad cow

antibiotics are only used sparingly. High levels of ARGs

disease, or bovine spongiform encephalopathy, BSE) and

(>10–4 copies/16S rRNA gene) were detected in water and

also because of the relationship between consumption of

sediment of the river, which passes through various land

infected cattle and incidence of human prion diseases such

uses such as urban agriculture and industrial zones.

as Creutzfeldt–Jakob disease (CJD) and others. It is very

Statistical analysis indicated that certain ARGs (tetM, tetO,

likely that soil serves as an important environmental

tetQ, tetW, blaOXA) were correlated to Cu and ampicillin.

reservoir for prions, and soil is though to play an important

Although the study does not give a definitive answer on the

role in indirect transmission of prion diseases among

relative influence of each pollutant on ARG occurrence, it

animals. Direct contact between animals is another major

showed that unregulated pollution has the potential of

route for prion disease transmission in that infectious prions

affecting ARGs.

have been detected in saliva, urine, and blood as well as in

The association between antibiotic resistance and

the central nervous system (CNS).

bacterial attachment was investigated for agricultural E. coli isolates (Liu et al. 2011).

There are many studies in 2011 that provided

Liu and co–workers

more information on the detection of prion in vivo, the

examined 203 E. coli isolates from swine facilities and

development of prions after uptake, and the fate and

found that bacterial attachment to quartz was positively

transport of prions in the environment. These results would

related to combined resistance to 6 antibiotics (i.e.,

be useful for prion disease control and prevention of

amoxicillin, streptomycin, tetracycline, sulfamethazin,

environment contamination by prions.

tylosin and chlortetracycline) but negatively related to

Prion Detection Methods. Currently, the most

combined resistance to 3 other antibiotics (i.e., nalidixic

popular TSEs diagnostic techniques are based on the

acid, kanamycin, and neomycin).

immunodetection of PrPSc by Western blotting (WB),

Surprisingly, no

enzyme–linked

immunosorbent

assay

(ELISA),


and

immunohistochemistry (IHC). They have been applied to a

detection of PrPSc from PASA in urine by combining of

number of studies identifying the existence of prions

SOFIA and PMCA indicated an alternate for antemortem

resistant to proteolysis. However, they are not sufficiently

diagnosis of prion disease.

sensitive to detect prions at extremely low levels.

Although widely used in prion detection, PMCA

This problem has been solved partially by the

detection of human prions in accessible body fluids was

development of a more sensitive method called protein

unsuccessful. For this reason, a highly sensitive assay

misfolding cyclic amplification (PMCA). It is an in–vitro

named ‘real–time QUIC’ (RT–QUIC) for the detection of

technique simulating the conversion and replication of

prion in human cerebrospinal fluid (CSF) was established

cellular prion protein (PrPC) to its infectious isoform

(Atarashi et al. 2011). This method was a combination of

(PrPSc) by repeated incubation and sonication of prion seed

QUIC technology and thioflavin T (ThT) fluorescence dye

and uninfected substrate. This new technique had then been

to monitor amyloid formation which possibly minimized

used widely in the detection of prions in various tissues and

the time necessary for the detection of protease–resistant

excreta which contain trace amount of prions that were

recombinant PrP. RT–QUIC had been successfully applied

unable to be detected by traditional methods (Garza et al.

to the assessment of more than 200 CSF specimens from

2011; Haley et al. 2011; Rubenstein et al. 2011; Terry et al.

Japanese and Australian patients with a more than 80%

2011).

accuracy for the correct diagnosis of CJD. This method Higher efficiency of PrPSc replication was

reported by

could also used for other prions and was able to quantify

Gonzalez-Montalban et al. (2011) by

PASA when combined with an end–point dilution of

modifying the original PMCA technique. The addition of

samples.

small amount of Teflon beads was found to increase the

Occurrence of Prions. Prions have been

conversion of PrPC to PrPSc from ~10% to up to 100% for

detected in the excretions, blood, and birthing matter of

selected prion strains. The sensitivity of prion detection in

CWD positive cervids and scrapie positive animal models,

one PMCA round (24 hours) was observed to increase by 2

environmental surfaces accessible for infected ovine

to 3 orders of magnitude.

animals, and natural aqueous environment. To identify the

Based on the application of PMCA, Rubenstein et

source(s) of infectious prions in the excreta, a study

al. (2011) provided the first report on prion disease–

conducted by

associated seeding activity (PASA) detection of PrPSc

proximate to saliva, urine, and fecal production of 27

from the urine of naturally or preclinical prion–diseased

white–tailed deer exposed to CWD positive/negative

ovine or cervids. Detection was achieved by using the

sources by serial PMCA. PrPCWD–generating activity was

surround optical fiber immunoassay (SOFIA) to measure

detected in a range of tissues and was highest in the

the products of limited serial PMCA. This newly developed

Haley et al. (2011) analyzed the tissues

salivary gland, urinary bladder, and distal intestinal tract.


Deer with highest levels of PrPCWD amplification in the

agents. Okada et al. (2011) analyzed 28 calves exposed to

brain had higher and more widely disseminated prion

5 g of homogenized brainstems confirmed as BSD agents.

amplification in excretory tissues.

Different results for the detection of prion were found in

Improvements on prion detection from ovine

different places in the continuous Peyer’s patch and the

animals were also made. Based on the previous results of

CNS, providing important information for understanding

detection of prions from excreta, blood, and birthing matter

the pathogenesis of BSE. The other study investigated the

of animal models, Terry et al. (2011) identified the

occurrence and distribution of disease–associated prion in

existence of prion in the faeces of sheep naturally infected

three different parts in the small intestine of cattle orally

with classical scrapie by using serial PMCA along with two

exposed to a 1 g or 100 g dose of a titrated BSE brainstem

extraction methods. 7 of 15 sheep in clinical phase and 14

homogenate Stack et al. (2011). Results were relative to the

of 14 sheep in preclinical phase showed amplification of

exposure dose and age, and suggested a very low BSE risk

PrPSc in their feaces, demonstrating that prion could be

from food products containing the jejunum and duodenum

shedded in faeces from a naturally infected host and was a

of cattle slaughtered for human consumption.

likely source of prion contamination in the environment.

To identify the first uptake and replication sites

Besides faeces, prions were also successfully

of prion in the gut, Kujala et al. (2011) reported the

detected in the liver of sheep naturally infected with scrapie

trafficking of prion toward Peyer’s patches of wild type and

and challenged with BSE, at both clinical and preclinical

PrP–deficient

stages of the disease. The result showed that PrPSc

immunofluorescence

accumulated in the liver of 89% of sheep naturally infected

microscopy. At 7–21 day post feeding (dpf), increased PrP

with scrapie and 100% of sheep challenged with BSE

labeling was observed on the plasma membranes of

(Everest et al. 2011). Moreover, in utero vertical

follicular dendritic cells (FDCs) in germinal centres of

transmission of scrapie has also been studied by Garza et

Peyer’s patches from wild type mice, identifying FDCs as

al. (2011). Six fetuses from three natural infected pregnant

the first sites of PrP conversion and replication.

mice and

using

high–resolution

cryo–immunogold

electron

ewes in an advanced clinical stage of scrapie were

Fate and Transport of Prions. Prions can enter

analyzed. For each fetus, samples from amniotic fluid,

the environment through decomposition of infected animal

brain, spleen, ileo–cecal valve and retropharyngeal lymph

carcasses or shedding from pre–clinical or clinical host

node showed amplification after PMCA, suggesting the

animals, and thus will enter the soil matrix or the aqueous

possibility of in utero transmission of scrapie in natural

environment. While prions can bind to soils, the interaction

infected sheep.

of prions with soil was found to be dependent on the

Two studies from Europe and Japan respectively

solvent, aging time, and soil types.

reported detection of prion in cattle orally exposed to BSE


Saunders et al. (2011)c investigated hyper (HY)

al. 2011a; Miles Miles et al. 2011b). Different temperature

strain of transmissible mink encephalopathy (TME)

ranges were utilized to treat prions in water and biosolids

adsorption to soil minerals in different aqueous solutions

for different incubation time periods, and a scrapie cell

including phosphate buffered saline (PBS), sodium

assay was performed to determine prion infectivity and

chloride, calcium chloride, and deionized water. Samples

quantity. Extraction of prions from biosolids was used with

incubated at different time periods were also studied with

4 M urea at 80°C for 10 minutes followed by a membrane

WB and PMCA for replication ability analysis. They found

centrifugation to reduce the concentration of urea.

that adsorption solution chemistry could affect prion

Reduction of infectious prions was reported for prions both

replication

in water and Class B biosolids, with higher reduction in

and

protease–resistance,

especially

after

incubation periods of 30 d or longer. However, soil bound

biosolids.

prions could remain a risk for prion disease transmission

While a lot of effort devoted by researchers to the

after months in the environment.

investigation of fate and transport of prions in soil and

In addition to the previously mentioned factors,

water, concerns on the transmission of prions by aerosols

soil type was suggested to be an important factor on the

arose (Stitz and Aguzzi 2011). Aerosols can originate very

behavior of soil bound prions (Saunders et al. 2011b).

easily in a broad variety of experimental and natural

When adsorbed to soil and soil minerals, HY TME yielded

environmental conditions. They are a virtually unavoidable

a greater–than–one–log decrease in PMCA replication

consequence of the handling of fluids thus complete

efficiency when binding to silty clay loam soil (SCL).

prevention of the generation of aerosols is very difficult.

Clay–

exhibited

Although there is no strong evidence indicating that prions

significantly lower replication efficiencies compared with

are airborne under natural circumstances, a relative study

sand–bound HY. Furthermore, infectivity of SCL–HY was

has reported that mouse scrapie can be efficiently

decreased by a 1.3–log in titer comparing to unbound

transmitted via aerosols (Haybaeck et al. 2011), leading to

control. These data suggested that dominant soil types in

a re–thinking on prion biosafety guidelines in research and

local sites may be a significant determinant in the

diagnostic laboratories due to the potential risk of airborne

environmental transmission of prion diseases. And an

prion transmission.

and

organic

surface–

bound

analysis from Walter et al. (2011)

HY

indicated that 1%

Degradation and Inactivation of Prions. Prions

increase in the clay–sized particle content in soils within

are known to be quite resistant to the conventional

the approximate home range of an individual deer increased

inactivation methods such as proteases, heat, radiation, and

its odds of infection by up to 8.9%.

formalin treatments, although their infectivity can be

Miles et al. evaluated the effect of temperature on

reduced by such treatments. Efficient inactivation options

the fate of prions in water and Class B biosolids (Miles et

may involve incineration, autoclaving, and/or harsh


chemical treatments which are not practical for most

providing a more practical option for the reduction of the

environmental applications. Therefore, more applicable

risk of prion disease transmission via soil or other

degradation and inactivation methods in situ for prions

environmental surfaces.

were explored.

Other than application of mild treatment by

One of the related studies was conducted by Piro

enzyme, two more studies focused on the degradation of

et al. (2011) who assumed that photodegradation of

prions with more environmentally friendly methods.

incorporated polyanions would alter prion infectivity

Johnson et al. (2011) found that acetone extracts of three

because polyanions were indicated as a possible cellular

lichen species (Parmelia sulcata, etc) had the ability to

cofactor necessary for the formation of infectious prions in

degrade prion protein from TSE–infected hamsters, mice,

vitro. To test this hypothesis, synthetic prions were

and deer. Reduction of PrPTSE was reported to be more

produced using a photocleavable, 100–base oligonucleotide

than two logs measured by immunoblots and PMCA.

(PC–oligo). In serial PMCA reactions, PC–oligo was

Additionally, reduced levels in PrPTSE–enriched preps or

incorporated into physical complexes with PrPSc molecules

infected brain homogenates were also found following

resistant to benzonase digestion and then exposed to long

exposure to freshly–collected P. sulcata or an aqueous

wave ultraviolet light (315 nm) which induced degradation

extract of the lichen. Lichen is ubiquitous in the

of PC–oligo into 5 base fragments. However, the bioassay

environment and has strong survival ability in challenging

in hamsters indicated that light–induced photolysis of

ecological niches, its inactivation ability for prions suggests

incorporated PC–oligo did not alter the infectivity of in

a possible source for agents to degrade prions. Observation

vitro–generated prions, which also meant that intact

of proteolysis of a recombinant prion in a lamb brain–

polyanions were not required for the maintenance of prion

amended loamy soil has been reported by Rapp et al.

infectivity.

(2011). In this study, a 15N–labelled recombinant PrP

Saunders et al. investigated the inactivation

(rPrP) was added to soil in which microbial biomass and

efficiency of soil bound prion with a commercially

soil proteolytic activity had been increased by either

purchased prionzyme (Saunders et al. 2011a). HY TME

simultaneous or prior amendment with lam brain. The

was adsorbed to a variety of soil and soil minerals at

majority of the recovered rPrP–N was associated with the

preferred conditions and then was treated with the

soil particles, which drew the conclusion that high content

prionzyme under environmentally relevant conditions

of animal organic matter with the sorption properties of

(22°C, pH 7.4). The amplification efficiency of treated soil

prion protein and stimulation of the soil microbial

samples was compared to controls of known infectious

component were required to predict prion transmission in

titer. Results suggested 104– to > 106–fold decreases in

soil.

soil bound prion infectivity following enzyme treatment,


Terry, L. A. (2011) Detection and localisation of PrPSc in

References

the liver of sheep infected with scrapie and bovine

Almeida, S. A. A.; Amorim, L. R.; Heitor, A. H.; Montenegro, M.

spongiform encephalopathy. Plos One, 6 (5), e19737.

C. B. S. M.; Barbosa, J.; Sa, L. C.; Sales, M. G. F. (2011)

Gall, H. E.; Sassman, S. A.; Lee, L. S.; Jafvert, C. T. (2011)

Rapid automated method for on-site determination of

Hormone

sulfadiazine in fish farming: a stainless steel veterinary

discharges

from

a

midwest

tile-drained

agroecosystem receiving animal wastes. Environ Sci

syringe coated with a selective membrane of PVC serving as

Technol, 45 (20), 8755-64.

a potentiometric detector in a flow-injection-analysis

Garza, M. C.; Fernandez-Borges, N.; Bolea, R.; Badiola, J. J.;

system. Anal Bioanal Chem, 401 (10), 3355-65.

Castilla, J.; Monleon, E. (2011) Detection of PrPres in

Atarashi, R.; Sano, K.; Satoh, K.; Nishida, N. (2011) Real-time

genetically susceptible fetuses from sheep with natural

quaking-induced conversion: A highly sensitive assay for

scrapie. Plos One, 6 (12), e27525.

prion detection. Prion, 5 (3), 150-153.

Gonzalez-Montalban, N.; Makarava, N.; Ostapchenko, V. G.;

Avbersek, M.; Zegura, B.; Filipic, M.; Heath, E. (2011) Integration

Savtchenk, R.; Alexeeva, I.; Rohwer, R. G.; Baskakov, I. V.

of GC-MSD and ER-Calux assay into a single protocol for

(2011)

determining steroid estrogens in environmental samples. Sci.

Highly

efficient

protein

misfolding

cyclic

amplification. Plos Pathog., 7 (2), e1001277.

Total Environ., 409 (23), 5069-5075.

Graham, D.; Olivares-Rieumont, S.; Knapp, C.; Lima, L.; Werner,

Bartelt-Hunt, S. L.; Snow, D. D.; Damon-Powell, T.; Brown, D.

D.;

L.; Prasai, G.; Schwarz, M.; Kolok, A. S. (2011)

Bowen,

E.

(2011) Antibiotic

Resistance Gene

Abundances Associated with Waste Discharges to the

Quantitative evaluation of laboratory uptake rates for

Almendares River near Havana, Cuba. Environmental

pesticides, pharmaceuticals, and steroid hormones using

Science & Technology, 45 (2), 418-424.

POCIS. Environ. Toxicol. Chem., 30 (6), 1412-1420.

Graves, A.; Liwimbi, L.; Israel, D.; van Heugten, E.; Robinson, B.;

Bera, M.; Radcliffe, D. E.; Cabrera, M. L.; Vencill, W. K.;

Cahoon, C.; Lubbers, J. (2011) Distribution of ten antibiotic

Thompson, A.; Hassan, S. (2011) 17beta-Estradiol and

resistance genes in E. coli isolates from swine manure,

Testosterone Sorption in Soil with and without Poultry

lagoon effluent and soil collected from a lagoon waste

Litter. J. Environ. Qual., 40 (6), 1983-1990.

application field. Folia Microbiologica, 56 (2), 131-137.

Bevacqua, C. E.; Rice, C. P.; Torrents, A.; Ramirez, M. (2011)

Haley, N. J.; Mathiason, C. K.; Carver, S.; Zabel, M.; Telling, G.

Steroid hormones in biosolids and poultry litter: A

C.; Hoover, E. A. (2011) Detection of chronic wasting

comparison of potential environmental inputs. Science of the

disease prions in salivary, urinary, and intestinal tissues of

Total Environment, 409 (11), 2120-2126.

deer: Potential mechanisms of prion shedding and

Colomer-Lluch, M.; Imamovic, L.; Jofre, J.; Muniesa, M. (2011)

transmission. J. Virol., 85 (13), 6309-6318.

Bacteriophages Carrying Antibiotic Resistance Genes in

Hansen, M.; Krogh, K. A.; Halling-Sorensen, B.; Bjorklund, E.

Fecal Waste from Cattle, Pigs, and Poultry. Antimicrobial

(2011) Determination of ten steroid hormones in animal

Agents and Chemotherapy, 55 (10), 4908-4911.

waste manure and agricultural soil using inverse and

Everest, S. J.; Ramsay, A. M.; Chaplin, M. J.; Everitt, S.; Stack, M.

integrated clean-up pressurized liquid extraction and gas

J.; Neale, M. H.; Jeffrey, M.; Moore, S. J.; Bellworthy, S. J.;


chromatography-tandem mass spectrometry. Analytical

during the Biotransformation of 17alpha-Ethinylestradiol

Methods, 3 (5), 1087-1095.

and Trimethoprim. Environmental Science & Technology,

Haybaeck, J.; Heikenwalder, M.; Klevenz, B.; Schwarz, P.;

45 (8), 3605-3612.

Margalith, I.; Bridel, C.; Mertz, K.; Zirdum, E.; Petsch, B.;

Kozlik, P.; Bosakova, Z.; Tesarova, E.; Coufal, P.; Cabala, R.

Fuchs, T. J.; Stitz, L.; Aguzzi, A. (2011) Aerosols transmit

(2011) Development of a solid-phase extraction with

prions to immunocompetent and immunodeficient mice.

capillary liquid chromatography tandem mass spectrometry

Plos Pathog., 7 (1), e1001257.

for analysis of estrogens in environmental water samples. J.

Heuer, H.; Solehati, Q.; Zimmerling, U.; Kleineidam, K.; Schloter,

Chromatogr., A, 1218 (15), 2127-2132.

M.; Muller, T.; Focks, A.; Thiele-Bruhn, S.; Smalla, K.

Kujala, P.; Raymond, C. R.; Romeijn, M.; Godsave, S. F.;

(2011) Accumulation of Sulfonamide Resistance Genes in

Kasteren, S. I.; Wille, H.; Prusiner, S. B.; Mabbott, N. A.;

Arable Soils Due to Repeated Application of Manure

Peters, P. J. (2011) Prion uptake in the gut: Identification of

Containing Sulfadiazine. Appl. Environ. Microbiol., 77 (7),

the first uptake and replication sites. Plos Pathog., 7 (12),

2527-2530.

e1002449.

Homklin,

S.;

Ong,

S.

K.;

Limpiyakorn,

T.

(2011)

Lanthier, M.; Scott, A.; Zhang, Y.; Cloutier, M.; Durie, D.;

Biotransformation of 17Î±-methyltestosterone in sediment

Henderson, V.; Wilkes, G.; Lapen, D.; Topp, E. (2011)

under different electron acceptor conditions. Chemo., 82

Distribution of selected virulence genes and antibiotic

(10), 1401-1407.

resistance in Enterococcus species isolated from the South

Iparraguirre, A.; Prieto, A.; Navarro, P.; Olivares, M.; Fernandez,

Nation River drainage basin, Ontario, Canada. Journal of

L.-A.; Zuloaga, O. (2011) Optimisation of stir bar sorptive

Applied Microbiology, 110 (2), 407-421.

extraction and in-tube derivatisation-thermal desorption-gas

Lee, J. H.; Zhou, J. L.; Kim, S. D. (2011) Effects of biodegradation

chromatography-mass spectrometry for the determination of

and sorption by humic acid on the estrogenicity of 17beta-

several endocrine disruptor compounds in environmental

estradiol. Chemo., 85 (8), 1383-1389.

water samples. Anal. Bioanal. Chem., 401 (1), 339-352.

Lin, C.-H.; Lerch, R. N.; Goyne, K. W.; Garrett, H. E. (2011)

Johnson, C. J.; Bennett, J. P.; Biro, S. M.; Duque-Velasquez, J. C.;

Reducing herbicides and veterinary antibiotics losses from

Rodriguez, C. M.; Bessen, R. A.; Rocke, T. E. (2011)

agroecosystems using Vegetative Buffers. J. Environ. Qual.,

Degradation of the disease-associated prion protein by a

40 (3), 791-799.

serine protease from lichens. Plos One, 6 (5), e19836.

Liu, P.; Soupir, M.; Zwonitzer, M.; Huss, B.; Jarboe, L. (2011)

Jones, S.; Burgos, J.; Lutnesky, M.; Sena, J.; Kumar, S.; Jones, L.;

Association of Antibiotic Resistance in Agricultural

Varela, M. (2011) Dairy Farm Age and Resistance to

Escherichia coli Isolates with Attachment to Quartz. Appl.

Antimicrobial Agents in Escherichia coli Isolated from

Environ. Microbiol., 77 (19), 6945-6953.

Dairy Topsoil. Current Microbiology, 62 (4), 1139-1146.

Lucci, P.; Nunez, O.; Galceran, M. T. (2011) Solid-phase

Khunjar, W. O.; Mackintosh, S. A.; Skotnicka-Pitak, J.; Baik, S.;

extraction using molecularly imprinted polymer for selective

Aga, D. S.; Love, N. G. (2011) Elucidating the Relative

extraction of natural and synthetic estrogens from aqueous

Roles of Ammonia Oxidizing and Heterotrophic Bacteria

samples. J. Chromatogr., A, 1218 (30), 4828-4833.


Malik, A.; Aleem, A. (2011) Incidence of metal and antibiotic

in

cattle

orally

infected

with

bovine

spongiform

resistance in Pseudomonas spp. from the river water,

encephalopathy agent. Transbound. Emerg. Dis., 58 (4),

agricultural soil irrigated with wastewater and groundwater.

333-343.

Environmental Monitoring and Assessment, 178 (1-4), 293-

Pan, X.; Qiang, Z. M.; Ben, W. W.; Chen, M. X. (2011) Residual

308.

veterinary antibiotics in swine manure from concentrated

Mansell, D. S.; Bryson, R. J.; Harter, T.; Webster, J. P.; Kolodziej,

animal feeding operations in Shandong Province, China.

E. P.; Sedlak, D. L. (2011) Fate of endogenous steroid

Chemo., 84 (5), 695-700.

hormones in steer feedlots under simulated rainfall-induced

Piro, J. R.; Harris, B. T.; Supattapone, S. (2011) In situ

runoff. Environ. Sci. Technol., 45 (20), 8811-8818.

photodegradation of incorporated polyanion does not alter

Mao, L.; Colosi, L. M.; Gao, S.; Huang, Q. (2011) Understanding

prion infectivity. Plos Pathog., 7 (2), e1002001.

Ligninase-Mediated Reactions of Endocrine Disrupting

Rapp, D.; Richaume, A.; Jame, P.; Rigou, P.; Rezaei, H.; Alcouffe,

Chemicals in Water: Reaction Rates and Quantitative

P.; Chapel, J. P.; Quiquampoix, H.; Potier, P. (2011)

Structure-Activity Relationships. Environmental Science &

Evidence for proteolysis of a recombinant prion protein in a

Technology, 45 (14), 5966-5972.

lamb brain-amended loamy soil. Eur. J. Soil Sci., 62, 607-

Mashtare, M. L.; Khan, B.; Lee, L. S. (2011) Evaluating

616.

stereoselective sorption by soils of 17Î±-estradiol and 17Î²-

Rubenstein, R.; Chang, B.; Gray, P.; Piltch, M.; Bulgin, M. S.;

estradiol. Chemo., 82 (6), 847-852.

Sorensen-Melson, S.; Miller, M. W. (2011) Prion disease

Meyer, B.; Pailler, J.-Y.; Guignard, C.; Hoffmann, L.; Krein, A. (2011)

Concentrations

of

dissolved

herbicides

detection, PMCA kinetics, and IgG in urine from sheep

and

naturally/experimentally infected with scrapie and deer with

pharmaceuticals in a small river in Luxembourg. Environ.

preclinical/clinical chronic wasting disease. J. Virol., 85

Monit. Assess., 180 (1-4), 127-146.

(17), 9031-9038.

Miles, S. L.; Takizawa, K.; Gerba, C. P. (2011a) Survival of

Saunders, S. E.; Bartz, J. C.; Vercauteren, K. C.; Bartelt-Hunt, S.

infectious prions in water. J. Environ. Sci. Heal. A, 46 (9),

L. (2011a) An enzymatic treatment of soil-bound prions

938-943.

effectively inhibits replication. Appl. Environ. Microb., 77

Miles, S. L.; Takizawa, K.; Gerba, C. P.; Pepper, I. L. (2011b)

(13), 4313-4317.

Survival of infectious prions in Class B biosolids. J.

Saunders, S. E.; Shikiya, R. A.; Langenfeld, K.; Bartelt-Hunt, S.

Environ. Sci. Heal. A, 46, 364-370.

L.; Bartz, J. C. (2011b) Replication efficiency of soil-bound

Munir, M.; Xagoraraki, I. (2011) Levels of Antibiotic Resistance

prions varies with soil type. J. Virol., 85 (11), 5476-5482.

Genes in Manure, Biosolids, and Fertilized Soil. J. Environ.

Saunders, S. E.; Yuan, Q.; Bartz, J. C.; Bartelt-Hunt, S. L. (2011c)

Qual., 40 (1), 248-255.

Effects of solution chemistry and aging time on prion

Okada, H.; Iwamaru, Y.; Imamura, M.; Masujin, K.; Matsuura, Y.;

protein adsorption and replication of soil-bound prions. Plos

Murayama, Y.; Mohri, S.; Yokoyama, T. (2011) Detection

One, 6 (4), e18752.

of disease-associated prion protein in the posterior portion

Sellin Jeffries, M. K.; Conoan, N. H.; Cox, M. B.; Sangster, J. L.;

of the small intestine involving the continuous peyer's patch

Balsiger, H. A.; Bridges, A. A.; Cowman, T.; Knight, L. A.;


Bartelt-Hunt, S. L.; Kolok, A. S. (2011) The anti-estrogenic

Walsh, F.; Ingenfeld, A.; Zampicolli, M.; Hilber-Bodmer, M.;

activity of sediments from agriculturally intense watersheds:

Frey, J.; Duffy, B. (2011) Real-time PCR methods for

Assessment using in vivo and in vitro assays. Aquatic

quantitative monitoring of streptomycin and tetracycline

Toxicology, 105 (1-2), 189-198.

resistance genes in agricultural ecosystems. J. Microbiol.

Stack, M. J.; Moore, S. J.; Vidal-Diez, A.; Arnold, M. E.; Jones, E.

Methods, 86 (2), 150-155.

M.; Spencer, Y. I.; Webb, P.; Spiropoulos, J.; Powell, L.;

Walter, W. D.; Walsh, D. P.; Farnsworth, M. L.; Winkelman, D.

Bellerby, P.; Thurston, L.; Cooper, J.; Chaplin, M. J.; Davis,

L.; Miller, M. W. (2011) Soil clay content underlies prion

L. A.; Everitt, S.; Focosi-Snyman, R.; Hawkins, S. A. C.;

infection odds. Nat. Comm., 2, 200.

Simmons, M. M.; Wells, G. A. H. (2011) Experimental

Writer, J. H.; Barber, L. B.; Ryan, J. N.; Bradley, P. M. (2011a)

bovine spongiform encephalopathy: Detection of PrPSc in

Biodegradation and Attenuation of Steroidal Hormones and

the small intestine relative to exposure dose and age. J.

Alkylphenols

Comp. Path., 145, 289-301.

Environmental Science & Technology, 45 (10), 4370-4376.

Stitz, L.; Aguzzi, A. (2011) Aerosols: An underestimated vehicle

by

Stream

Biofilms

and

Sediments.

Writer, J. H.; Ryan, J. N.; Barber, L. B. (2011b) Role of Biofilms

for transmission of prion diseases? Prion, 5 (3), 138-141.

in Sorptive Removal of Steroidal Hormones and 4-

Strauss, C.; Harter, T.; Radke, M. (2011) Effects of pH and

Nonylphenol Compounds from Streams. Environmental

Manure on Transport of Sulfonamide Antibiotics in Soil. J.


Environ. Qual., 40 (5), 1652-1660.

Xu, B. J.; Mao, D. Q.; Luo, Y.; Xu, L. (2011) Sulfamethoxazole

Terry, L. A.; Howells, L.; Bishop, K.; Baker, C. A.; Everest, S. J.;

biodegradation and biotransformation in the water-sediment

Thorne, L.; Maddison, B. C.; Gough, K. C. (2011) Detection

system of a natural river. Bioresource Technology, 102 (14),

of prions in the faeces of sheep naturally infected with

7069-7076.

classical scrapie. Vet. Res., 42, 65.

Yang, Y.-Y.; Pereyra, L. P.; Young, R. B.; Reardon, K. F.; Borch,

Torres-Cortes, G.; Millan, V.; Ramirez-Saad, H.; Nisa-Martinez,

T. (2011) Testosterone-Mineralizing Culture Enriched from

R.; Toro, N.; Martinez-Abarca, F. (2011) Characterization

Swine Manure: Characterization of Degradation Pathways

of novel antibiotic resistance genes identified by functional

and Microbial Community Composition. Environmental

metagenomics


on

soil

samples.

Environmental

Microbiology, 13 (4), 1101-1114.

Zhang, H.-C.; Yu, X.-j.; Yang, W.-c.; Peng, J.-f.; Xu, T.; Yin, D.-

Trinh, T.; Harden, N. B.; Coleman, H. M.; Khan, S. J. (2011)

Q.; Hu, X.-l. (2011) MCX based solid phase extraction

Simultaneous determination of estrogenic and androgenic

combined with liquid chromatography tandem mass

hormones in water by isotope dilution gas chromatography-

spectrometry for the simultaneous determination of 31

tandem mass spectrometry. J. Chromatogr., A, 1218 (12),

endocrine-disrupting compounds in surface water of

1668-1676.

Shanghai. J. Chromatogr., B: Anal. Technol. Biomed. Life

Veach, A. M.; Bernot, M. J. (2011) Temporal variation of

Sci., 879 (28), 2998-3004.

pharmaceuticals in an urban and agriculturally influenced

Zhao, J.-L.; Ying, G.-G.; Chen, F.; Liu, Y.-S.; Wang, L.; Yang, B.;

stream. Sci. Total Environ., 409 (21), 4553-4563.

Liu, S.; Tao, R. (2011) Estrogenic activity profiles and risks


in surface waters and sediments of the Pearl River system in South China assessed by chemical analysis and in vitro bioassay. J. Environ. Monit., 13 (4), 813-821.
