Dietary Intake Contributed the Most to Chlorinated Paraffin Body Burden in a Norwegian Cohort.

Determining the major human exposure pathways is a prerequisite for the development of effective management strategies for environmental pollutants such as chlorinated paraffins (CPs). As a first step, the internal and external exposure to CPs were quantified for a well-defined human cohort. CPs in participants' plasma and diet samples were analyzed in the present study, and previous results on paired air, dust, and hand wipe samples were used for the total exposure assessment. Both one compartment pharmacokinetic modeling and forensic fingerprinting indicate that dietary intake contributed the most to body burden of CPs in this cohort, contributing a median of 60-88% of the total daily intakes. The contribution from dust ingestion and dermal exposure was greater for the intake of long-chain CPs (LCCPs) than short-chain CPs (SCCPs), while the contribution from inhalation was greater for the intake of SCCPs than medium-chain CPs (MCCPs) and LCCPs. Significantly higher concentrations of SCCPs and MCCPs were observed in diets containing butter and eggs, respectively (p < 0.05). Additionally, other exposure sources were correlated to plasma levels of CPs, including residence construction parameters such as the construction year (p < 0.05). This human exposure to CPs is not a local case. From a global perspective, there are major knowledge gaps in biomonitoring and exposure data for CPs from regions other than China and European countries.

Human Exposure to Chlorinated Paraffins via Inhalation and Dust Ingestion in a Norwegian Cohort.

Very-short- (vSCCPs, C6-9), short- (SCCPs, C10-13), medium- (MCCPs, C14-17), and long-chain chlorinated paraffins (LCCPs, C>17) were analyzed in indoor air and dust collected from the living rooms and personal 24 h air of 61 adults from a Norwegian cohort. Relatively volatile CPs, i.e., vSCCPs and SCCPs, showed a greater tendency to partition from settled indoor dust to paired stationary indoor air from the same living rooms than MCCPs and LCCPs, with median logarithmic dust-air partition ratios of 1.3, 2.9, 4.1, and 5.4, respectively. Using the stationary indoor air and settled indoor dust concentrations, the combined median daily exposures to vSCCPs, SCCPs, MCCPs, and LCCPs were estimated to be 0.074, 2.7, 0.93, and 0.095 ng/kg bw/d, respectively. Inhalation was the predominant exposure pathway for vSCCPs (median 99%) and SCCPs (59%), while dust ingestion was the predominant exposure pathway for MCCPs (75%) and LCCPs (95%). The estimated inhalation exposure to total CPs was ∼ 5 times higher when the personal 24 h air results were used rather than the corresponding stationary indoor air results in 13 paired samples, indicating that exposure situations other than living rooms contributed significantly to the overall personal exposure. The 95th percentile exposure for CPs did not exceed the reference dose.

Complex Mixtures of Chlorinated Paraffins Found in Hand Wipes of a Norwegian Cohort.

Up to 18000 ng of total chlorinated paraffins (CPs) was found in hand wipes of individual adult participants in a Norwegian cohort study (n = 60), with a geometric mean (SD) value of 870 (2700) ng. The CPs covered a wide range of alkane chain lengths from C7 to C48 with variable chlorine substitution. Complex mixtures of very-short-chain (vSCCPs, C<10), short-chain (SCCPs, C10-13), medium-chain (MCCPs, C14-17), and long-chain (LCCPs, C>17) CPs were found, contributing on average 0.3%, 20%, 58%, and 22%, respectively, of the total CPs. Significant positive correlations were found between CP levels and factors related to the indoor environment and product use, including living in a house/apartment built before the ban of SCCPs, having a sofa, the number of TVs in the home, and owning a car, which mirrors CP usage as flame retardants and/or plasticizers in consumer products. Compared to previous studies of other organic contaminants in hand wipe samples from the same cohort, CPs were the most abundant flame retardants. This is the first report of CPs in hand wipes, and dermal exposure based on these data suggested that hand contact could be an important human exposure pathway for LCCPs.

Multiple pathways of human exposure to poly- and perfluoroalkyl substances (PFASs): From external exposure to human blood.

Exposure to PFASs may result in adverse health effects. This study aimed to characterise the exposure to PFASs from diet, house dust, indoor air, and dermal contact and the relative contribution from different external exposure pathways to human serum concentrations. Daily intakes of 18 perfluoroalkyl acids (PFAAs) and 12 PFAA precursors from diet, dust ingestion, inhalation of indoor air and dermal absorption were estimated using a comprehensive dataset comprising 61 adults from the Oslo area, Norway. Concentrations of PFAAs and PFAA precursors in house dust, indoor air, hand wipes, foods and drinks were utilised to estimate the daily intakes. Perfluorooctanesulfonate (PFOS) was the predominant PFAS in serum for this study group. On a median level, perfluorooctanoate (PFOA) contributed most to the total estimated daily intake of PFAAs, with a median intake of 280 (range: 72-1810) pg·kg bw-1·day-1, covering both direct and indirect (precursors) exposure. Out of this, only 3% (range: <1-48%) of the total PFOA intake came from indirect exposure. Dietary exposure from ingestion of food and drinks was in general the predominant exposure pathway, followed by exposure from ingestion of house dust, inhalation of indoor air, and dermal absorption, but considerable variations were observed among individuals. House dust ingestion and indoor air inhalation contributed most to the total intakes for some participants, for which most of them were among the 20% participants with the highest total estimated intakes. Some statistical significant associations between concentrations of PFASs measured in serum and estimated intakes were observed. Measured serum concentrations and modelled serum concentrations based on external exposure estimates were in the same order of magnitude for PFOS, PFHxS, PFOA, and PFNA, but only PFOA concentrations were comparable, 1.9 and 2.0 ng mL-1 for observed and modelled serum concentrations, respectively. The estimated daily intakes of PFASs in this study were lower than the health-based guidance values, e.g. the tolerable weekly intakes derived by EFSA. This study underlines the importance of performing studies considering multiple exposure pathways on an individual basis.

Serum concentrations of legacy and emerging halogenated flame retardants in a Norwegian cohort: Relationship to external exposure.

Sixty-one serum samples from a Norwegian cohort were analyzed for 43 emerging and legacy halogenated flame retardants (HFRs). BDE-47, -153, -197 and -209 were detected in >56% of the samples with median concentrations of 0.23, 1.0, 0.64 and 1.5 ng/g lipid, respectively. BDE-49, -85, -99, -100, -154, -206, -207, -208 as well as HBB, syn- and anti-DDC-CO, OBTMPI, DBDPE, α-HBCDD and TBBPA were also detected in some serum samples (detection frequencies of 2-36%). Other tri-octaBDEs, TBP-AE, α- and ß-DBE-DBCH, BATE, pTBX, αß-TBCO, PBBz, TBCT, PBT, PBEB, DPTE, EH-TBB, BTBPE, BEH-TEBP, HCDBCO, ß- and γ-HBCDD were below the limits of detection (mLOD). Concentrations of individual BDE congeners detected in this study were within the range from previous European studies. Positive correlations were seen between concentrations of BDE-47 in dust and BDE-153 in serum, between BDE-153 in dust and BDE-153 in serum, and between BDE-153 masses in handwipes and BDE-47 concentrations in serum (Spearman's rank, 0.29 < r < 0.43). Associations between the number of phones/mobiles, numbers of electronic equipment per person in the home and the consumption of specific food categories (such as soups/spices/sauces and alcoholic beverages) with BDE-47 and -153 serum levels were confirmed by multivariate linear regression analyses. The measured median serum level of BDE-47 was slightly over-predicted by a factor of 5.5 whereas other BDE congeners were under-predicted by factors of 13-6000 when compared to serum concentrations predicted from external exposure media (inhalation, dermal uptake, dietary intake from duplicate diet and dust ingestion) using a simple one compartment pharmacokinetic (PK) model. BDE-153 was not detected and BDE-197 not analyzed in food so no dietary intake assessments for these could be made, which may partially explain the discrepancies between their measured and predicted serum concentrations. Overall, our results suggest that exposure via diet is the most important exposure pathway for BDE-47 and -209, with diet being responsible for more than 96% of the total daily intake of these two BDEs in the Norwegian cohort.

Human exposure pathways to organophosphate flame retardants: Associations between human biomonitoring and external exposure.

Organophosphate flame retardants (PFRs) have largely replaced the market of polybrominated diphenyl ethers (PBDEs). Concerns about PFR contamination and its impact on human health have consequently increased. A comprehensive investigation on the human exposure pathways to PFRs is to be endeavoured. This study investigated the occurrence of PFR metabolites in human urine, serum and hair, correlating them with external exposure data that was presented in our previous studies. Participants from Oslo (n = 61) provided a set of samples, including dust, air, handwipes, food, urine, serum and hair. Associations between PFR metabolites analyzed in the biological samples and the PFRs in environmental samples were explored. Different sampling strategies for dosimeters (e.g. floor/surface dust, personal/stationary air) were also compared to understand which is better for predicting human exposure to PFRs. Seven out of the eleven target PFR metabolites, including diphenyl phosphate (DPHP) and bis(1-chloro-2-propyl)-1-hydroxy-2-propyl phosphate (BCIPHIPP), were frequently detected (DF > 30%) in urine. DPHP was the most frequently detected metabolite in both serum and hair. Several PFR metabolites had higher levels in morning urine than in afternoon urine. Floor dust appeared to be a better proxy for estimating PFR internal exposure than surface dust, air, and handwipes. Some PFRs in handwipes and air were also correlated with their metabolites in urine and hair. Age, beverage consumption and food consumption were negatively associated with DPHP levels in urine. Discrepancies observed between the external and internal exposure for some PFRs call for further investigation on PFR bioaccessibility and clearance.

Hand Wipes: A Useful Tool for Assessing Human Exposure to Poly- and Perfluoroalkyl Substances (PFASs) through Hand-to-Mouth and Dermal Contacts.

The indoor environment contributes considerably to human exposure to poly- and perfluoroalkyl substances (PFASs). This study estimated the human exposure to PFASs from the indoor environment through hand-to-mouth and dermal contacts using hand wipes. An analytical method was developed to determine 25 PFASs in hand wipe samples collected as a composite sample from both hands of 60 adults. Polyfluoroalkyl phosphate esters (PAPs) were the predominant PFASs in the hand wipe samples (medians between 0.21 and 0.54 ng per sample). Positive and significant correlations were observed between PAPs, perfluorooctanesulfonate (PFOS), and perfluorooctanoate (PFOA) in hand wipes. Low frequency of daily hand washing (≤8 times day-1) was associated with 30-50% higher concentrations of PFOS, PFOA, and 8:2diPAP in hand wipes. Further, significant correlations between paired hand wipes and house dust samples were observed for PFOS, PFOA, and 6:2diPAP. Also, a significant correlation between PFOS in hand wipes and EtFOSE in indoor air was found. This finding indicates either a common source of exposure or a transformation of EtFOSE to PFOS in the environment or on the hands. The contributions of direct and indirect exposure to perfluoroalkyl acids (PFAAs) showed that PFOA contributed the highest exposure to adults via hand-to-mouth and dermal contacts, followed by PFOS. The median of estimated daily intakes via hand-to-mouth and dermal contacts (for hands only) for PFOA were 0.83 and 0.50 pg·kg bw-1·day-1, respectively. This study gives a first indication that PFAS concentrations in hand wipes can be used as a proxy for the exposure to PFASs from indoor environments, but further studies are needed to confirm this.

Dried blood spots for reliable biomonitoring of poly- and perfluoroalkyl substances (PFASs).

Dried blood spot (DBS) sampling has gained attention in several scientific areas because of the low sampling burden. The study aimed to develop a method for the determination of poly- and perfluoroalkyl substances (PFASs) in DBS using a standardized blood volume. The DBS method using a simple methanol extraction followed by online solid phase extraction-ultra high performance liquid chromatography-tandem mass spectrometry quantification was validated. Only 30 µL of blood is required. Based on the measurements of DBS dispersed areas from known blood volumes (20-70 µL), the blood volume on a 3 mm diameter DBS subsample was calculated to be 3.3 µL (median, n = 708 measurements, 59 adults). Strong correlations of PFAS concentrations between finger prick DBSs and venous whole blood samples (n = 57) were found (rho 0.72-0.97, p < 0.0001). Also, Passing-Bablok regressions and Bland-Altman plots demonstrated good agreements of PFAS concentrations in finger prick DBSs and venous whole blood samples. This finding indicates that the DBS method was satisfactory, and allows straightforward analysis of PFASs in DBS without hematocrit correction. This DBS method is reliable for accurate determination of PFASs and has a high potential for use of self-collected DBS in large-scale biomonitoring studies as well as for archived DBS samples.

Assessment of dermal exposure to halogenated flame retardants: Comparison using direct measurements from hand wipes with an indirect estimation from settled dust concentrations.

There are few studies estimating dermal exposure to halogenated flame retardants in adults. To fill this gap, sixty-one hand wipe samples were collected from a Norwegian adult cohort using gauze pads immersed in isopropanol. BDE-47, BDE-209, bis(2­ethyl­hexyl)­3,4,5,6­tetrabromophthalate (BEH-TEBP) and decabromodiphenylethane (DBDPE) were the most frequently detected chemicals. The highest median mass in hand wipes was that of sumEHFR (570 ng), followed by sumHBCDD (180 ng) and sumPBDE (2.9 ng). The high EHFR level was mainly driven by tetrabromobisphenol A (TBBPA) which accounted for 77% of the total mass. Positive and significant correlations were observed between FR levels in hand wipes and settled dust (0.26 < r < 0.56, p < 0.05), as well as between FR levels in hand wipes and the number of electronic consumer products at home (0.27 < r < 0.40, p < 0.05). Significant bivariate associations with number of laptops/tablets and phones/mobiles were further confirmed by multivariate linear regression analyses. Dermal exposure was estimated using the levels measured in handwipes. The estimated median dermal exposure was 2600, 840 and 6.2 pg/kg bw/d for sumEHFR, sumHBCDD and sumPBDE, respectively. Further, we compared these results with the dermal exposure as estimated indirectly by utilizing previously reported FR levels in settled dust collected from the residences of the same studied cohort. With the indirect approach, higher dermal exposures to sumPBDE but lower exposures to sumEHFR and sumHBCDD were observed compared to the direct dermal exposure estimated via hand wipes. Comparable exposure estimates between hand wipes and the indirect method were obtained for α­, ß­tetrabromoethylcyclohexane (DBE-DBCH), DBDPE, BDE-28, -35, -49, -99, -153, 154, and -183. For other individual HFRs, the exposure estimates obtained from the two approaches were significantly different (Mann-Whitney U test, p < 0.05). Both methods gave similar dermal exposure estimates for many individual FRs. However, it is important to be aware of the value and limitations of each method when using them to estimate human exposure.

Distribution of Novel and Well-Known Poly- and Perfluoroalkyl Substances (PFASs) in Human Serum, Plasma, and Whole Blood.

Currently, there is limited knowledge on the distribution of poly- and perfluoroalkyl substances (PFASs) in different blood matrices, particularly for novel PFASs such as polyfluoroalkyl phosphate esters (PAPs) and perfluoroalkyl phosphonates (PFPAs). To explore this, serum, plasma, and whole blood from 61 adults in Oslo, Norway were collected. The largest number of PFASs were detected in whole blood. For PAPs and PFPAs, the highest frequencies of detection and concentrations were observed in plasma. PAPs contributed to 8% of total PFASs in plasma (median, 0.81 ng mL-1). Perfluorohexylphosphonate (PFHxPA) was the dominant PFPA, regardless of blood matrix. The relative composition profiles of PFASs in blood matrices differed. For some specific PFASs such as perfluorooctanesulfonamide (PFOSA) and perfluorohexanoate (PFHxA), the highest concentrations were observed in whole blood. The PFAS concentration ratios varied between blood matrices, depending on the compounds. However, similar ratios were observed for 6:2 polyfluoroalkyl phosphate diester (6:2diPAP) as well as well-known PFASs such as perfluorooctanesulfonate (PFOS) and perfluorooctanoate (PFOA). Besides the determination of 25 PFASs in human blood, this study also lead to better understanding of biomonitoring data from different blood matrices, which is key knowledge for performing both exposure assessments and epidemiological studies.

Estimating human exposure to perfluoroalkyl acids via solid food and drinks: Implementation and comparison of different dietary assessment methods.

BACKGROUND: Diet is a major source of human exposure to hazardous environmental chemicals, including many perfluoroalkyl acids (PFAAs). Several assessment methods of dietary exposure to PFAAs have been used previously, but there is a lack of comparisons between methods. AIM: To assess human exposure to PFAAs through diet by different methods and compare the results. METHODS: We studied the dietary exposure to PFAAs in 61 Norwegian adults (74% women, average age: 42 years) using three methods: i) by measuring daily PFAA intakes through a 1-day duplicate diet study (separately in solid and liquid foods), ii) by estimating intake after combining food contamination with food consumption data, as assessed by 2-day weighted food diaries and iii) by a Food Frequency Questionnaire (FFQ). We used existing food contamination data mainly from samples purchased in Norway and if not available, data from food purchased in other European countries were used. Duplicate diet samples (n=122) were analysed by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) to quantify 15 PFAAs (11 perfluoroalkyl carboxylates and 4 perfluoroalkyl sulfonates). Differences and correlations between measured and estimated intakes were assessed. RESULTS: The most abundant PFAAs in the duplicate diet samples were PFOA, PFOS and PFHxS and the median total intakes were 5.6ng/day, 11ng/day and 0.78ng/day, respectively. PFOS and PFOA concentrations were higher in solid than liquid samples. PFOS was the main contributor to the contamination in the solid samples (median concentration 14pg/g food), while it was PFOA in the liquid samples (median concentrations: 0.72pg/g food). High intakes of fats, oils, and eggs were statistically significantly related to high intakes of PFOS and PFOA from solid foods. High intake of milk and consumption of alcoholic beverages, as well as food in paper container were related to high PFOA intakes from liquid foods. PFOA intakes derived from food diary and FFQ were significantly higher than those derived from duplicate diet, but intakes of PFOS derived from food diary and FFQ were significantly lower than those derived from duplicate diet. We found a positive and statistically significant correlation between the PFOS intakes derived from duplicate diet with those using the food diary (rho=0.26, p-value=0.041), but not with the FFQ. Additionally, PFOA intakes derived by duplicate diet were significantly correlated with estimated intakes from liquid food derived from the food diary (rho=0.34, p=0.008) and estimated intakes from the FFQ (rho=0.25, p-value=0.055). CONCLUSIONS: We provide evidence that a food diary or a FFQ-based method can provide comparable intake estimates to PFOS and PFOA intakes derived from a duplicate diet study. These less burdensome methods are valuable and reliable tools to assess dietary exposure to PFASs in human studies.

Human Exposure to Legacy and Emerging Halogenated Flame Retardants via Inhalation and Dust Ingestion in a Norwegian Cohort.

In this study, we estimated human exposure to polybrominated diphenyl ethers (PBDEs), hexabromocyclododecanes (HBCDDs), and several emerging flame retardants (EFRs) via inhalation and dust ingestion. Sixty indoor stationary air samples, 13 personal air samples, and 60 settled dust samples were collected from a Norwegian cohort during winter 2013. PBDEs showed the highest median concentration in dust (1200 ng/g), followed by EFRs (730 ng/g) and HBCDDs (190 ng/g). The PBDE concentrations in dust were mainly driven by BDE-209 and those of EFRs by bis(2-ethylhexyl) tetrabromophthalate. EFRs predominated in stationary air samples, with 2-ethylhexyl 2,3,4,5-tetrabromobenzoate and 4-(1,2-dibromoethyl)-1,2-dibromocyclohexane having the highest median concentrations (150 and 25 pg/m3 (sum of α- and ß-isomers), respectively). Different profiles and concentrations were observed in personal air samples compared to the corresponding stationary air samples. In relation to inhalation exposure, dust ingestion appears to be the major exposure pathway to FRs (median total exposure 230 pg/kg bw/d, accounting for more than 65% of the total exposure) for the Norwegian cohort. The calculated exposure due to air inhalation was substantially lower when the stationary air concentrations were used rather than personal air concentrations (43 pg/kg bw/d versus 130 pg/kg bw/d). This suggests that other exposure situations (such as outdoors or in offices) contributed significantly to the overall personal exposure, which cannot be included by using only a stationary air sampling technique. The median and 95th percentile exposures for all target FRs did not exceed the reference dose.

Assessment of dietary exposure to organohalogen contaminants, legacy and emerging flame retardants in a Norwegian cohort.

Polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), polybrominated diphenyl ethers (PBDEs), emerging halogenated flame retardants (EHFRs) and organophosphate flame retardants (PFRs) were detected in 24h duplicate diet samples from a Norwegian cohort (n=61), with concentrations ranging from

Legacy and alternative flame retardants in Norwegian and UK indoor environment: Implications of human exposure via dust ingestion.

Indoor dust has been acknowledged as a major source of flame retardants (FRs) and dust ingestion is considered a major route of exposure for humans. In the present study, we investigated the presence of PBDEs and alternative FRs such as emerging halogenated FRs (EHFRs) and organophosphate flame retardants (PFRs) in indoor dust samples from British and Norwegian houses as well as British stores and offices. BDE209 was the most abundant PBDE congener with median concentrations of 4700ngg-1 and 3400ngg-1 in UK occupational and house dust, respectively, 30 and 20 fold higher than in Norwegian house dust. Monomeric PFRs (m-PFRs), including triphenyl phosphate (TPHP), tris(chloropropyl) phosphate (TCPP) and tris(2-chloroethyl) phosphate (TCEP) dominated all the studied environments. To the best of our knowledge, this is the first report of isodecyldiphenyl phosphate (iDPP) and trixylenyl phosphate (TXP) in indoor environments. iDPP was the most abundant oligomeric PFR (o-PFR) in all dust samples, with median concentrations one order of magnitude higher than TXP and bisphenol A bis(diphenyl phosphate (BDP). iDPP and TXP worst-case scenario exposures for British workers during an 8h exposure in the occupational environment were equal to 34 and 1.4ngkgbw-1day-1, respectively. The worst-case scenario for BDE209 estimated exposure for British toddlers (820ngkgbw-1day-1) did not exceeded the proposed reference dose (RfD) (7000ngkgbw-1day-1), while exposures for sum of m-PFRs (Σm-PFRs) in British toddlers and adults (17,900 and 785ngkgbw-1day-1 respectively) were an order of magnitude higher than for Norwegian toddlers and adults (1600 and 70ngkgbw-1day-1).

Comprehensive Study of Human External Exposure to Organophosphate Flame Retardants via Air, Dust, and Hand Wipes: The Importance of Sampling and Assessment Strategy.

We compared the human exposure to organophosphate flame retardants (PFRs) via inhalation, dust ingestion, and dermal absorption using different sampling and assessment strategies. Air (indoor stationary air and personal ambient air), dust (floor dust and surface dust), and hand wipes were sampled from 61 participants and their houses. We found that stationary air contains higher levels of ΣPFRs (median = 163 ng/m(3), IQR = 161 ng/m(3)) than personal air (median = 44 ng/m(3), IQR = 55 ng/m(3)), suggesting that the stationary air sample could generate a larger bias for inhalation exposure assessment. Tris(chloropropyl) phosphate isomers (ΣTCPP) accounted for over 80% of ΣPFRs in both stationary and personal air. PFRs were frequently detected in both surface dust (ΣPFRs median = 33 100 ng/g, IQR = 62 300 ng/g) and floor dust (ΣPFRs median = 20 500 ng/g, IQR = 30 300 ng/g). Tris(2-butoxylethyl) phosphate (TBOEP) accounted for 40% and 60% of ΣPFRs in surface and floor dust, respectively, followed by ΣTCPP (30% and 20%, respectively). TBOEP (median = 46 ng, IQR = 69 ng) and ΣTCPP (median = 37 ng, IQR = 49 ng) were also frequently detected in hand wipe samples. For the first time, a comprehensive assessment of human exposure to PFRs via inhalation, dust ingestion, and dermal absorption was conducted with individual personal data rather than reference factors of the general population. Inhalation seems to be the major exposure pathway for ΣTCPP and tris(2-chloroethyl) phosphate (TCEP), while participants had higher exposure to TBOEP and triphenyl phosphate (TPHP) via dust ingestion. Estimated exposure to ΣPFRs was the highest with stationary air inhalation (median =34 ng·kg bw(-1)·day(-1), IQR = 38 ng·kg bw(-1)·day(-1)), followed by surface dust ingestion (median = 13 ng·kg bw(-1)·day(-1), IQR = 28 ng·kg bw(-1)·day(-1)), floor dust ingestion and personal air inhalation. The median dermal exposure on hand wipes was 0.32 ng·kg bw(-1)·day(-1) (IQR = 0.58 ng·kg bw(-1)·day(-1)) for ΣTCPP. The selection of sampling and assessment strategies could significantly affect the results of exposure assessment.

A fast and sensitive method for the simultaneous analysis of a wide range of per- and polyfluoroalkyl substances in indoor dust using on-line solid phase extraction-ultrahigh performance liquid chromatography-time-of-flight-mass spectrometry.

A fast and sensitive method for simultaneous determination of 18 traditional and 6 alternative per- and polyfluoroalkyl substances (PFASs) using solid-liquid extraction (SLE), off-line clean-up using activated carbon and on-line solid phase extraction-ultrahigh performance liquid chromatography-time-of-flight-mass spectrometry (on-line SPE-UHPLC-TOF-MS) was developed. The extraction efficiency was studied and recoveries in range the 58-114% were obtained. Extraction and injection volumes were also optimized to 2mL and 400µL, respectively. The method was validated by spiking dust from a vacuum cleaner bag that had been found to contain low levels of the PFASs in focus. Low method detection limits (MDLs) and method quantification limits (MQLs) in the range 0.008-0.846ngg(-1) and 0.027-2.820ngg(-1) were obtained, respectively. For most of the PFASs, the accuracies were between 70 and 125% in the range from 2 to100ngg(-1) dust. Intra-day and inter-day precisions were in general well below 30%. Analysis of a Standard Reference Material (SRM 2585) showed high accordance with results obtained by other laboratories. Finally, the method was applied to seven indoor dust samples, and PFAS concentrations in the range 0.02-132ngg(-1) were found. The highest median concentrations were observed for some of the alternative PFASs, such as 6:2-diPAP (25ngg(-1)), 8:2-diPAP (49ngg(-1)), and PFOPA (23ngg(-1)), illustrating the importance of inclusion of new PFASs in the analytical methods.

Innovative determination of polar organophosphonate pesticides based on high-resolution Orbitrap mass spectrometry.

The determination of compounds showing a very low molecular weight (i.e. < 200 Da) can be complicated when low-resolution mass spectrometry is used in the selected-reaction monitoring mode, since the possible number of product ions is reduced and the obtained reactions are not selective enough to overcome background noise and/or matrix interferences. In this study, the use of high-resolution mass spectrometry based on Exactive Orbitrap was applied for the determination of a group of polar organophosphonate pesticides and transformation products (TPs), which show the aforementioned features, in agricultural soils. Namely, glyphosate, glufosinate, ethephon and their TPs, aminomethyl phosphonic acid (AMPA), 3-methylphosphinicopropionic acid, N-acetyl-glufosinate and 2-hydroxyethylphosphonic acid were analyzed. The [M-H](-) ions 168.00564, 180.04202, 142.96593, 110.00016, 151.01547, 222.05259 and 124.99982 were used, respectively, for the detection and identification of the compounds. Confirmation was carried out by using accurate mass measurements of ion fragments for each compound, from neutral losses of CO(2), H(2)O and H(2)CO (formaldehyde). Furthermore, the recently reported tool, relative isotopic mass defect (RΔm), was also used to support the confirmation protocol. The optimized method was fully validated at low levels, including the estimation of a not commonly used parameter: the limit of confirmation (LOC). This LOC is expressed as the lowest concentration of compound that can be confirmed using a fragment or the RΔm, and it ranged from 10 to 50 µg kg(-1) for all compounds. All the data was obtained in a single injection. Finally, the method was applied to real soil samples, and glyphosate and AMPA were found at 265 µg kg(-1) and 105 µg kg(-1), respectively.

Comparison of several extraction procedures for the determination of biopesticides in soil samples by ultrahigh pressure LC-MS/MS.

A new procedure has been proposed for the determination of biopesticides (nicotine, sabadine, veratridine, rotenone, azadirachtin, cevadine, deguelin, spynosad D, and pyrethrins) and piperonyl butoxide in agricultural soils. Several extraction procedures such as solid-liquid extraction using mechanical shaking, sonication, pressurized liquid extraction, and modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) have been tested, obtaining better results when QuEChERS procedure without further cleanup steps was applied. The determination of the compounds was carried out by ultra high pressure liquid chromatography coupled to tandem mass spectrometry, using methanol and aqueous solution of ammonium formate 5 mM as mobile phase. The method was validated for all compounds at concentrations ranging from 10 to 100 µg/kg and recoveries ranged from 68 to 116%, except for nicotine and sabadine, with recoveries lower than 50%. Precision was estimated through intra- and inter-day studies, obtaining intra-day precision lower than 20% for most of the compounds, and inter-day precision was lower than 25%. Limits of detection and quantification were also estimated, obtaining limits of quantification equal or lower than 10 µg/kg. Finally, the method was applied to the analysis of 20 real agricultural soil samples and no biopesticide residues were found over the limit of quantification.

Evaluation of soil contamination in intensive agricultural areas by pesticides and organic pollutants: south-eastern Spain as a case study.

A comprehensive survey of the occurrence and fate of pesticides and organic contaminants in soils from an intensive agricultural area devoted to horticultural production in plastic-based greenhouses has been performed to determine if the operation under integrated pest management practices has contributed to reduce the levels of these compounds. Almería province (south-eastern Spain) was selected for the case study. 38 agricultural soil samples (each sample corresponds to an independent private greenhouse) of areas working under integrated pest management (IPM) programs have been analyzed in order to evaluate their contamination fate. Sampling was designed to cover an area of about 400 km(2). Pesticides, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), phenolic compounds and di-(2-ethylhexyl)phthalate (DEHP) were monitored. The obtained results were compared to other studies reported in Spain and Europe. Among relevant persistent pesticides, DDTs and endosulfans were mainly found and the results indicated historical application, although recent application of endosulfan was rarely detected. PAHs were also found but to a lesser extent and derived from pyrogenic sources. DEHP levels were considerably higher in comparison to the other monitored analytes. The evaluation revealed that despite the use of IPM programs, pesticide and organic contaminants are still being detected in this type of agricultural soil, although at relatively low concentration levels. In general, the contamination rate was similar or lower in comparison to other agricultural areas from nearby regions or countries. However, further monitoring studies should be carried out to establish the possible reduction in contamination by the selected compounds.

Application of a quick, easy, cheap, effective, rugged and safe-based method for the simultaneous extraction of chlorophenols, alkylphenols, nitrophenols and cresols in agricultural soils, analyzed by using gas chromatography-triple quadrupole-mass spectrometry/mass spectrometry.

Due to the different physico-chemical properties of phenols, the development of a methodology for the simultaneous extraction and determination of phenolic compounds belonging to several families, such as chlorophenols (CPs), alkylphenols (APs), nitrophenols (NTPs) and cresols is difficult. This study shows the development and validation of a method for the analysis of 13 phenolic compounds (including CPs, APs, NTPs and cresols) in agricultural soils. For this purpose, a quick, easy, cheap, effective, rugged and safe (QuEChERS)-based procedure was developed, validated and applied to the analysis of real samples. A derivatization step prior to the final determination by gas chromatography (GC) coupled to a triple quadrupole analyzer operating in tandem mass spectrometry (QqQ-MS/MS) was performed by using acetic acid anhydride (AAA) and pyridine (Py). The optimized procedure was validated, obtaining average extraction recoveries in the range 69-103% (10microgkg(-1)), 65-98% (50microgkg(-1)), 76-112% (100microgkg(-1)) and 76-112% (300microgkg(-1)), with precision values (expressed as relative standard deviation, RSD)< or =22% (except for 4-chlorophenol) involving intra-day and inter-day studies. Furthermore, 15 real soil samples were analyzed by the proposed method in order to assess its applicability. Some phenolic compounds (e.g. 2,4,6-trichlorophenol or 4-tert-octylphenol) were found in the samples at trace levels (<10microgkg(-1)).