chlorinated paraffins 
 ( cps ) , also known as polychlorinated n - alkanes ( pcas ) , 
 are complex mixtures of carbon chains 
 of variable length and a variable number of chlorine atoms .
they are 
 currently produced in high volumes ( > 1 million tons year in china alone ) .
concerns are rising 
 regarding their ubiquitous occurrence and high persistence in the 
 environment , including detection in remote 
 areas .
so - called short - chain cps ( sccps ) , 
 cps with carbon chain lengths between 10 and 13 , are under scrutiny 
 as these compounds have a high bioaccumulation potential and are chronically toxic to aquatic organisms .
they 
 are , therefore , classified as substances of very high concern and 
 are listed as key compounds for monitoring in several legislations 
 and guidelines .
they are currently candidates to be designated as 
 persistent organic pollutants ( pops ) under the stockholm convention . 
 in the case of the medium - chain cps ( mccps ) ( c14c17 ) and long - chain cps ( lccps ) ( c18 ) , relevant 
 information on their levels , fates , and potential hazards to the environment 

however , 
 the current restrictions on the use of sccps are expected to result 
 mainly in a replacement by mccps in many applications .
the insufficient data about cps is partly due to 
 limitations regarding 
 the reliability of analytical methods to identify and quantify these 
 compounds . to date , the existing analytical methods for the determination 
 of cps suffer all from serious drawbacks that makes a reliable quantification 
 difficult .
developed 
 a promising instrumental technique to determine sccps , mccps , and 
 lccps in environmental matrices in a single measurement run with a 
 particularly fast method using high resolution mass spectrometry . 

reliable cp exposure data is needed , particularly in regions where 
 the cp levels and fate are still unknown . in australia , for example , 

limited data on cps exists , and the capability of analyzing cps is 
 lacking . until today , only two nonpeer reviewed studies describe the 
 presence of cps in the australian environment .
gillet et al . reported sccps in indoor and outdoor air in 
 melbourne with median concentrations of 52 ng / m and 81 
 ng / m , respectively .
reported sccps , mccps , and lccps in mussels , crabs , and 
 sediments collected near a cp manufacturer in australia .
the levels 
 were , respectively , 2300 g / kg lipid weight ( lw ) , 23  200 
 g / kg lw , and 9300 g / kg lw in mussels , and 64  900 
 g / kg lw , 30  500 g / kg lw and 14  300 g / kg 
 lw in crabs . in the sediment , the concentrations ranged from 61 to 
 440 g / kg dry weight ( dw ) for the sccps ; from 1100 to 16  400 
 g / kg dw for the mccps ; and from 900 to 3190 g / kg dw 
 for the lccps . despite the lack of information , the presence of at 
 least local cp contamination is highly likely .
australia manufactures 
 mccps and lccps ( e.g. , in orica , melbourne ) with ongoing investments 
 for expansion of cp manufacturing facilities . according to a government desktop study
, sccps were imported into australia in large quantities ( e.g. , 360 
 tonnes ) between 1998 and 2000 and were still imported at approximately 
 25 tonnes / year in 2002 .
mccps and lccps were imported into australia 
 in 2002 in even higher quantities at approximately 475 tonnes / year . 

nicnas reported that it is most likely 
 that the use of mccps and lccps in australia have increased due to 
 their replacement of the sccps .
while current information is lacking , 
 to our knowledge , sccp import or use is still permitted in australia . 
 in 2002
sccps were mainly used as lubricants in the australian metal 
 working industry ( 70% ) , and therefore , 
 major releases of cps in australia are thought to be from production , 
 both from spills or facility wash - down , and from industrial usage , 
 either from improper disposal of used metalworking lubricants or carry - off 
 from work pieces .
such releases of cps 
 occur either directly or through wastewater treatments plants ( wwtps ) . as cps are emerging pops , determining the levels 
 of cps near suspected sources ( i.e. , wwtps )
would facilitate a first 
 understanding on their release , presence , and potential risks of these 
 compounds .
therefore , this study aims to determine cps in sewage sludge 
 samples ( also known as biosolids ) from various wwtps in order to allow 
 a first evaluation of sccp , mccp , and lccp levels in australia .
information about the standards , chemicals and 
 suppliers is provided 
 in the supporting information ( si ) of this 
 manuscript .
pooled ( eight subsamples from each 
 wwtp ) sewage sludge samples were collected in 2014 at 15 different 
 wwtps in australia ( figure 1 ) .
the wwtps were located in five of eight states and territories 
 of australia , servicing populations of between 25  000 and 600  000 
 people , representing a combined population of approximately 2.5 million 
 people ( over 10% of the australian population ) .
total cp concentrations in ng / g dry weight measured in the sewage 
 sludge samples from australia .
the lccp values with an r lower than 0.5 are highlighted with red stripes and 
 are semiquantitative values .
( wa = western australia ; nt = northern 
 australia ; sa = south australia ; qld = queensland ; nsw = new south 
 wales ; vic = victoria ; tas = tasmania . after freeze - drying , approximately 
 0.20.3
g of the sewage sludge sample was extracted by pressurized 
 liquid extraction ( ple ) on an ase350 ( dionex , sunyvale , ca ) .
extraction 
 was performed with n - hexane / acetone ( 3:1 , v / v ) at 
 100 c and 1500 psi with a heat- , and static - time of 5 min using 
 three extraction cycles .
cleanup was performed in two steps first 
 with aluminum oxide ( 8% h20 ) and second with silicagel 
 ( 1.5% h20 ) columns .
briefly , 15 g of aluminum oxide ( 8% 
 h20 ) was weighed into a glass column . after washing the 
 aluminum oxide column with 25 ml of n - hexane
, the 
 extracts were brought on top of the column followed by elution of 
 the cps with 170 ml of n - hexane . during the second 
 cleanup ,
1.8 g of silicagel ( 1.5% h20 ) was weighed into 
 a glass column .
the silicagel column was washed with 6 ml of n - hexane before the sample extract was added .
fractionation 
 was performed in two fractions , the first one consisted of 14 ml of n - hexane ( waste fraction ) and the second one of 15 ml 15% 
 diethyl ether in n - hexane ( the cps fraction ) .
the 
 fraction was evaporated under nitrogen and solvent changed to 0.5 
 ml acetonitrile ( acn ) and transferred to an lc - vial followed by addition 
 of 100 l of injection standard c6pcp 
 ( 700 pg/l in acn ) .
measurement of 
 the cps in the australian 
 sewage sludge samples was performed with a slightly adopted analytical 
 method recently developed by bogdal et al .
briefly , without using an analytical column , 10 l of the 
 cleaned sewage sludge extract was directly injected into the qtof - hrms 
 ( triple tof 5600 + sciex , concord , ontario , canada ) running in the 
 negative atmospheric pressure chemical ionization ( apci ) mode .
the 
 injection was performed with an shimadzu nexera hplc system ( shimadzu 
 corp . ,
kyoto , japan ) using acn as eluent with an isocratic flow of 
 250 l / min . to increase the sensitivity of the cp detection 
 in negative apci mode , dichloromethane ( dcm ) at a flow rate of 40 

l / min was used as a dopant and mixed with the eluent just before 
 it entered the ion source ( bogdal et al . , ( 10 ) .
addition of dcm results 
 in an excess cl- ions in the ion source and significantly enhances 
 the formation of [ m+cl]- .
cps were analyzed with the apci - qtof - hrms 
 using the following settings .
the declustering potential ( dp ) was set at 
 90 v , and collision energy ( ce ) of 10 v was used . 

the mass spectrometer was operated in tof - ms mode measuring the full 
 scan range of m / z 2001500 . 

the minimal resolution was 10  000 ( minimum of 7000 is required 
 for the separation of the m / z values 
 of the most important [ m+cl]- ions ) .
external 
 mass calibration was performed with the sciex apci negative calibration 
 solution 5600 , which consist of a mix of known molecular weight polypropylene 
 glycols ( ppgs ) . in total
, 558 m / z ratios were extracted from the full scan mass spectra using multiquant 
 3.0 software ( sciex ) .
the 558 m / z ratios are related to the two most abundant m / z signals of the cp isotope cluster corresponding to the 
 cp congener groups with chain lengths of c10cl4 to c27cl27 ( si table s10 ) .
quantification of 
 the sccps , mccps , and lccps was based on a mathematical algorithm 
 recently applied by bogdal et al . for 
 the quantification of cps in various environmental matrices .
an example of the deconvolution whereby the 
 cp pattern measured in the sludge sample s2 was reconstructed into 
 a linear combination of patterns of cps of the technical mixtures 
 is shown in figure 2 .
as example for the reconstruction , the total mccp concentration 
 in sample s2 is 3150 ng / g dw ,
which is attributed to 1082 ng / g dw 
 mccp 42% cl , 1582 ng / g dw mccp 52% cl , and 486 ng / g dw mccp 57% cl 
 ( table 1 ) . an example 
 of chlorinated paraffins ( sccps , mccps , and lccps ) patterns 
 in sewage sludge sample s2 .
for each chlorinated paraffin group ( sccps , 
 mccps , and lccps ) the measured pattern is given ( a , c , e ) and the 
 reconstructed pattern based on deconvolution of the technical chlorinated 
 paraffin mixtures ( b , d , f ) .
deconvolution of the sccp pattern in 
 the sewage sample was performed with the 51.5% cl , 55.5% cl , and 63% 
 sccp standards , for the deconvolution of the mccp pattern the 42% 
 cl , 52% cl , and 57% cl mccp standards and for the deconvolution of 
 the lccp pattern the 36% cl and 49% cl lccp standards were used .
the 
 goodness of fit ( r ) for the deconvolution 
 is also given .
italic = r lower 
 than 0.5 therefore reported as tentative values . in our study , the variation in response 
 factors observed for sccps , 
 mccps , and lccps were considerable less depending on their chain length 
 and chlorination degree than in the study of bogdal et al . , . therefore ,
the quantification results are also 
 less impacted by the goodness of fit ( r ) between the cp patterns in the technical mixtures and the sample . 
 with their analytical setup , bogdal et al . , tested different technical cp mixtures with known concentration 
 and reported that an r of 0.50 for sccps 
 results in a quantification differences by a factor of 4 from the 
 expected concentration .
for mccps with an r > 0.60 the differences between calculated and expected concentration 
 is a factor of 2 and for the lccps with an r > 0.50 results in an differences of an factor less than 
 1.2 . 
 because in our study the response differences for the sccps , mccps , 
 and lccps were comparable with those reported for mccps and lccps 
 by bogdal et al .
, the differences between 
 calculated and expected concentration here are also estimated to be 
 below a factor of 2 for a r > 0.50 . 

therefore , 
 values with an r < 0.50 are reported 
 as tentative values .
an example of the measured and reconstructed 
 sccp , mccp , and lccp patterns in three sewage sludge samples are provided 
 in the figures 2 and si s5s7 .
three recovery standards , containing 
 all eight commercial cp standards 
 with known concentrations ( 120160 ng absolute , were included 
 in this study and underwent the same treatment as the 15 sewage sludge 
 samples .
acceptable recoveries were observed for all three cp categories 
 with mean sccps , mccps , and lccps recoveries of 79% , 81% , and 92% , 
 respectively ( si tables s3 and s8 ) .
the 
 goodness of fit ( r ) was higher than 0.93 
 for all mixtures .
although acceptable recoveries were observed for 
 the cp categories ( sccps , mccps , lccps ) , the recoveries of the lowest 
 chlorinated cp formulations within a cp category were somewhat low , 
 with recoveries down to 56% for the sccp 51.5% cl , and down to 42% 
 for the mccp 42% cl .
these lower recoveries are related to the somewhat 
 reduced sensitivity of the apci - qtof - hrms for cps with a lower chlorination 
 degree and shorter chain length .
matrix interferences were investigated 
 by spiking four of the analyzed sewage sludge samples with environmentally 
 realistic concentrations of three sccp , three mccp , and two lccp mixtures 
 in the concentration range of 120160 ng absolute .
the mean 
 recoveries of the four sccp , mccp , and lccp - spiked sewage sludge samples 
 ranged from 86 to 123% , and the r was 
 higher than 0.93 , with the exception of the lccp - spiked s2 sample , 
 which had an r of 0.54 ( si tables s3 and s8 ) .
overall , the results of the spiked sewage 
 sludge samples were comparable with the results of the recovery standards 
 which indicate that the results were not influenced by matrix interferences .
the stability of the apci - qtof - hrms was investigated by performing 
 an 8-fold measurement of a cleaned s9 sewage sludge sample ( si table s9 ) . whereas , bogdal et al . , reported that multiple injections are required 
 to obtain a good estimate of the average response factor ( rf ) , in 
 this study an injection standard ( c6 -pcp ) 
 was applied to correct for the variability .
the relative standard 
 deviation ( rsd ) of the injection standard ( c6-pcp ) of the 8-fold sewage sludge sample was 5% .
the rsd of the sum 
 of the cp congeners corrected for the internal standard was 5% , 2% , 
 and 4% , for respectively for the sccps ( 685 ng / g dw ) , mccps ( 3192 
 ng / g dw ) , and lccps ( 960 ng / g dw ) .
the calculated rsds indicate that 
 the variability of the apci - qtof - hrms was low , and by using an injection 
 standard , multiple injections were not needed .
as expected at levels 
 close to the loq ( peak area around 200 counts ) , the rsd went up to 
 a maximum of 46% , and decreased to 20% if the peak area increased 
 10 times and decreased to 5% if the peak area increased 100 times 
 ( si table s10 ) .
one sewage sludge sample 
 ( s12 ) was also extracted , cleaned , and analyzed in duplicate .
comparable 
 levels were observed for this duplicate sample with sccps of < 86 
 and < 60 ng / g dw , mccps of 995 and 1016 ng / g dw , and lccps of 625 
 and 527 ng / g dw ( table 1 ) .
regardless of the effort to reduce background contamination , 
 aluminum 
 oxide was heated to 250 c ; silica was prerinsed with dichloromethane 
 and methanol before use ; and all glassware was rinsed with both n - hexane and acetone prior to use , low cp levels were observed 
 in the two blank samples ( table 1 ) .
the total cp levels observed in the two blanks were 
 up to 16 ng absolute for the sccps , up to 24 ng absolute for the mccps , 
 and up to 0.5 ng absolute for the lccps .
therefore , all cp values 
 observed in the sewage sludge samples were blank corrected , and only 
 the corrected levels higher than 3 times the blank were reported in 
 this study .
all mccp and lccp values observed in the 15 sewage sludge 
 samples were at least 10 times higher than the cp values in the blank . 

for some sccp values , the levels were lower than 3 times the blank 
 and therefore reported as < loq .
the cp patterns observed in the 
 blanks were different from the patterns observed in the sewage sludge 
 samples , which indicates that the contamination is not related to 
 cross - contamination during sample treatment but more likely to another 
 source(s ) ( figures 3 and s1 ) .
the patterns in the blank were 
 mainly dominated by the short chain cps , c10 , and c11 for the sccps 
 and c14 for the mccps .
composition of mccps in the 15 sewage sludge samples and 
 the two 
 blanks ( the composition of the sccps and lccps is given in si figure s1 ) .
composition based on carbon number 
 ( left ) or chlorine number ( right ) .
the chlorination degree of the eight standard technical cp 
 formulations 
 we measured in this study were compared with the stated chlorination 
 degree of the manufacturer ( si table s2 ) .
for the higher chlorinated cp formulations , the calculated chlorination 
 degree was close to the stated chlorination degree .
however , for the 
 lower chlorinated cp formulations , the calculated values were somewhat 
 higher ( sccp ; 51.5% cl , calculated cl 55.9% , mccp ; 42% cl , calculated 
 49.4% cl , lccp ; 36% cl , calculated 41.4% cl ) .
congener patterns of 
 the eight technical cp mixtures are shown in si figures s2s4 .
bogdal et al . , reported that the sensitivity 
 of the apci - qtof - hrms method increased with chain length and chlorination 
 degree .
the authors observed a differences in response by a factor 
 of 50 between the sccp 49% cl and the sccp 70% formulations ; whereas 
 the response of mccp 45% cl and mccp 56% cl formulations differed 
 only by a factor 4 . in our study
we used the same analytical technique , 
 but with different instrumental equipment and adapted instrumental 
 setup conditions .
the differences in sensitivity in our study was 
 less depending on the chain length and chlorine degree .
for example 
 the differences in response between sccp 51.5% cl and sccp 63% cl 
 was only a factor of 1.9 , between mccp 42% and mccp 57% a factor 3.2 , 
 and between lccp 36% cl and lccp 49% a factor of 1.2 .
this indicates 
 that the sensitivity of the apci - qtof - hrms method is influenced by 
 the analytical set up and the instrumental equipment used .
calibration 
 standards were prepared in acn from the eight cp stock 
 solutions and ranged from 0.1 ng/l to 10 ng/l for the 
 sccps and mccps and from 0.05 ng/l to 10 ng/l for the 
 lccps .
the linear range of the calibration curve were determined using 
 the excel linear regression tool .
the linear range of the calibration 
 curve for the sccps and mccps ranged from 0.1 to 10 ng/l ; whereas 
 for the lccp , it ranged from 0.055.0 ng/l with an r > 0.99 . for the sccps , the lowest concentration 
 of the calibration curve , 0.1 ng/l , corresponds to the loq 
 ( 10 times the signal / noise ) , whereas for both the mccps and the lccps , 
 the loq could easily be lowered by a factor of 4 .
however , all sccps 
 and mccps concentrations detected in the sewage sludge samples was 
 above 0.1 ng/l and above 0.05 ng/l for the lccps .
mccps 
 were the dominant cps and were detected in all sludge samples with 
 concentrations ranging from 542 to 3645 ng / g dw ( table 1 ) . in eight of the 15 samples 

sccps were detected with concentrations ranging from < 57 to 1421 
 ng / g dw .
the lccps concentrations ( 116960 ng / g dw ) were comparable 
 to the sccp concentrations ( table 1 ) .
nine of the 15 lccps levels were reported as tentative 
 values due to a deconvolution result with an r < 0.5 .
the results of the total cps ( sum of sccps , mccps , 
 and lccps ) detected in sewage sludge collected at the various wwtps 
 around australia are illustrated in figure 1 .
the highest total cp concentration ( 5880 
 ng / g dw ) were detected in sewage sludge from location s4 in the northern 
 territory of australia .
however , elevated levels were also detected 
 in south - east queensland ( location s2 ; 4416 ng / g dw ) , south australia 
 ( location s9 ; 4737 ng / g dw ) and western australia ( location s13 ; 4567 
 ng / g dw ) .
the total cp concentrations were higher than the mean - , 
 - , -hbcdd concentrations ( 0.11129 ng / g ) and 
 mean bde209 concentrations ( 671340 ng / g dw ) detected in the 
 same sewage sludge samples .
to our knowledge , this is the first time that cps were detected 
 in australian sewage sludge .
the sccp and mccp concentrations observed 
 in the australian sewage sludge were comparable with the sccp and 
 mccp concentrations observed in swedish sewage sludge collected between 
 2004 and 2010 ( median sccps ; 1100 ng / g dw , median mccps ; 3800 ng / g 
 dw ) , czech sludge samples collected in 
 2004 near a chemical company in usti ( sccps ranged from 205 to 396 
 ng / g dw , mccps ranged from 736 to 2301 ng / g dw ) , and swiss sewage sludge collected in 2007 around zrich 
 ( sccp ; 135581 ng / g dw , mccps ; 10708960 ng / g dw ) .
measured only sccps ( 75859 ng / g dw ) in sewage sludge from 
 germany collected in the early 2000s , which were also comparable with 
 the sccp concentrations observed in our study .
higher sccp concentrations 
 were found in municipal and industrial sewage sludge in china with 
 concentrations from 800 to 52  700 ng / g dw .
the highest cp concentrations were found in municipal and 
 industrial sewage sludge from the uk reported by stevens el al .
, with sccp concentrations ranging from 6900 to 
 200  000 ng / g dw and mccps concentrations from 30 to 9700 ng / g 
 and by nicholls et al . , with sum sccp 
 and mccps concentrations ranged from 1800 to 93  100 ng / g dw . 
 these concentrations were up to 200-fold higher than those reported 
 in our study .
only 
 olofsson et al . has reported lccps in 
 sewage sludge samples from sweden with median concentrations of 31  000 
 ng / g dw .
the lccp concentrations were 8-fold higher than the median 
 mccps reported in that study and 28-fold higher than the median sccps 
 in that study .
these concentrations are 300-fold higher than the lccp 
 concentrations observed in australian sewage sludge in this study . 

this may indicate a higher usage and demand of cps in sweden compared 
 to australia .
other reasons for the difference could be a different 
 composition of the technical cp mixtures , or a different treatment 
 of wwtp system . despite the huge challenges and uncertainties 
 in quantification 
 of cps , the order of magnitude differences observed indicate that 
 point sources of cps can be very important . in two studies ,
no correlation was observed between the cp concentration and the 
 wwtp location , treatment capacity and serving population . in our study 

the correlation between the cp concentrations in the sewage sludge 
 samples and the wwtp size ( population ) , geographical location ( southern 
 queensland versus northern queensland ) and sewage sludge treatment 
 ( anaerobic versus aerobic / activated ) was investigated by comparing 
 the cp concentrations ( multiple t test ) .
taken into 
 account the relative small data set , only a significant higher mean 
 cp concentration was observed in the anaerobic treated sewage sludge 
 compared to the aerobic / activated sludge treatment ( p < 0.05 ) .
however , other factors may have influenced this result ; 
 as for example , all anaerobic wwtps were of large size . a more extensive 
 study is needed to draw more solid conclusions regarding cp concentrations 
 and wwtp characteristics .
the carbon and chlorine homologue groups 
 for the sccps , mccps and 
 lccps in the australian sewage sludge are given in figure 3 and si figure s1 . among the sewage sludge samples collected at different 
 locations in australia ,
similar carbon and chlorine homologue patterns 
 were observed for the sccps , mccps , and lccps .
the calculated chlorination 
 degree for the sewage sludge ranged from 57.8 to 63% for the sccps , 
 from 53.5 to 57.5% for the mccps , and from 39.9 to 48.3% for the lccps . 

, who studied the sccp composition in various 
 sewage sludge samples from china and observed similar carbon and chlorine 
 homologue profiles among different wwtps
. however , the sccp homologue 
 pattern observed in the sewage sludge from china was different than 
 the pattern observed in the australian sewage sludge . in the chinese 
 sludge , the sccp homologue groups were dominated by c11 ( 37% ) followed by c10 ( 27% ) and c12 ( 23% ) 
 with cl7 ( 37% ) and cl8 ( 29% ) , whereas in our 
 study the sccp homologue groups were dominated by c13 ( 51% ) 
 followed by c12 ( 24% ) and c11 ( 18% ) with cl7 ( 37% ) and cl6 ( 26% ) . taking into account the different 
 instrumental techniques used , these findings may indicate that the 
 cp composition of the commercial sccp mixtures used in china are different 
 than used in australia .
cps in china are not divided in sccps , mccps , 
 and lccps , but into different technical products .
the most common 
 technical products are cp-42 ( 42% cl ) , cp-52 ( 52% cl ) , and cp-70 ( 70% 
 cl ) .
cp-42 and cp-52 are the most widely produced in china ( over 80% ) 
 in 2005 and contain apparently 34% and 2540% sccps , 
 respectively .
zeng et al . only detected some mccps in sewage sludge from china , and 
 these were at low concentrations , which is in contrast to our study 
 where mccps were dominant .
this may indicate that mccps are probably 
 used in lesser amounts in china compared to australia .
however , in 
 soil and sediment of highly industrial areas in china ( pearl river 
 delta ) , higher mccp levels were observed compared to sccps , and the 
 opposite was observed across more rural areas .
this , together with an increased mccps / sccps ratio in a sediment 
 core in time , suggests an increased usage to mccps in recent years 
 in the pearl river delta .
overall , the 
 carbon homologue group patterns for the sccps and mccps in the australian 
 sewage sludge were more comparable with the patterns found in sewage 
 sludge from the uk and switzerland which were 
 also dominated by c11c13 for the sccps 
 and c14c15 for the mccps . until 
 today , lccps were only reported by olofsson et al . in swedish sewage sludge as total lccp concentration ( median 
 of 31  000 ng / g dw ) and by bogdal et al . in sewage sludge form
the total 
 lccp levels reported by bogdal et al . were only based on the c19c27 congener 
 groups .
the c18 was excluded by bogdal et al . after studying the complete c10-c27 pattern whereby
the technical mccp ( 52% cl ) formulation 
 contained up to 10% of c18 of the lccp congener groups . 

they observed that after subtracting the c18 congener group , 
 the remaining pattern in the sewage sludge was more comparable with 
 the pattern in the technical lccp formulations ( 40 , 49 , and 70% cl ) , 
 which would improve the deconvolution process . in both standard technical 
 lccp mixtures ( 36% cl and 49% cl ) used in this study ,
also the technical standard mccp mixtures ( 42% , 
 52% , and 57% cl ) used in our study contain only up to 1.3% lccps as 
 an impurity .
therefore , lccps could be calculated through deconvolution 
 using only two standard lccp technical mixtures ( 36% cl and 49% cl ) 
 instead of three for the sccps and mccps ( figure 2 ) .
lccp homologue groups in the australian 
 sewage sludge were dominated by c18 ( 30% ) followed by c19 ( 13% ) and c20 ( 10% ) , with cl7 ( 22% ) , 
 cl6 ( 18% ) , cl8 ( 17% ) , and cl4 , cl5 , cl9 ( each 11% ) .
the only two exceptions were 
 sewage sludge sample s4 from the northern territory of australia , 
 which had a pattern dominated by c27 ( 45% ) , and sewage 
 sludge sample s12 from south australia , which was dominated by c23c26 .
no clear explanation could be given , 
 but it may be related to local sources .
the lccps technical mixtures 
 contain mainly c18c20 and almost no 
 long chain lccps ( c21c27 ) .
therefore , 
 samples which are dominated by the longer chain lccps ( c21c27 ) , can not be entirely reconstructed by the 
 lccp technical mixtures .
this explains the low r calculated between the measured and reconstructed pattern 
 for the sewage sludge samples s4 and s12 , which were dominated with 
 the longer chain lccps . for both samples the lccp levels are reported 
 as tentative levels .
this is the first study that applies the 
 promising and particularly 
 fast instrumental technique recently develop by bogdal et al .
, routinely for simultaneously quantifying and 
 profiling sccps , mccps , and lccps in australian sewage sludge . due 
 the toxicity , bioaccumulation potency and persistency sccps are already 
 regulated and phased - out in europe and targeted by the stockholm convention . however , lccps and mccps are hardly regulated and the knowledge 
 about them is poor .
first studies show that the mccp / sccp ratios in 
 sediment , soil , and biota increased in recent years , which may be 
 influenced by the replacement of sccps by mccps .
however , data on mccps and lccps in the 
 environment is rare , and more research is needed to further understand 
 the risk and fate of cps in the environment .
especially , because more 
 than 59% of all the sewage sludge in australia is reused in agriculture 
 and through landfilling , the cps re - enter into the environment .
 to simultaneously quantify and profile 
 the complex mixture of short- , 
 median- , and long - chain cps ( sccps , mccps , and lccps ) in australian 
 sewage sludge , we applied and further validated a recently developed 
 novel instrumental technique , using quadrupole time - of - flight high 
 resolution mass spectrometry running in the negative atmospheric pressure 
 chemical ionization mode ( apci - qtof - hrms ) . without using an analytical 
 column the cleaned extracts 
 were directly injected into the qtof - hrms 
 followed by quantification of the cps by a mathematical algorithm . 
 
 the recoveries of the four sccp , mccp and lccp - spiked sewage sludge 
 samples ranged from 86 to 123% . 
 this apci - qtof - hrms method is a fast 
 and promising technique for routinely measuring sccps , mccps , and 
 lccps in sewage sludge . 
 australian sewage sludge was dominated by 
 mccps with concentrations ranging from 542 to 3645 ng / g dry weight 
 ( dw ) . 
 lower sccps concentrations ( < 571421 ng / g dw ) were 
 detected in the australian sewage sludge , which were comparable with 
 the lccps concentrations ( 116960 ng / g dw ) . 
 this is the first 
 time that cps were reported in australian sewage sludge . 
 the results 
 of this study gives a first impression on the distribution of the 
 sccps , mccps , and lccps in australia wastewater treatment plants ( wwtps ) . 
Introduction
MaterialS
and Methods
Results and Discussion