Linking past uses of legacy SVOCs with today's indoor levels and human exposure

Development of a supramolecular solvent-based extraction method for application to quantitative analyses of a wide range of organic contaminants in indoor dust

This study investigates the efficacy of supramolecular solvent (SUPRAS) in extracting a diverse spectrum of organic contaminants from indoor dust. Initially, seven distinct SUPRAS were assessed across nine categories of contaminants to identify the most effective one. A SUPRAS comprising Milli-Q water, tetrahydrofuran, and hexanol in a 70:20:10 ratio, respectively, demonstrated the best extraction performance and was employed for testing a wider array of organic contaminants. Furthermore, we applied the selected SUPRAS for the extraction of organic compounds from the NIST Standard Reference Material (SRM) 2585. In parallel, we performed the extraction of NIST SRM 2585 with conventional extraction methods using hexane:acetone (1:1) for non-polar contaminants and methanol (100%) extraction for polar contaminants. Analysis from two independent laboratories (in Norway and the Czech Republic) demonstrated the viability of SUPRAS for the simultaneous extraction of twelve groups of organic contaminants with a broad range of physico-chemical properties including plastic additives, pesticides, and combustion by-products. However, caution is advised when employing SUPRAS for highly polar contaminants like current-use pesticides or volatile substances like naphthalene.

Effects of novel flame retardants tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) and triphenyl phosphate (TPhP) on function and homeostasis in human and rat pancreatic beta-cell lines

Despite the fact that environmental pollution has been implicated in the global rise of diabetes, the research on the impact of emerging pollutants such as novel flame retardants remains limited. In line with the shift towards the use of non-animal approaches in toxicological testing, this study aimed to investigate the effects of two novel flame retardants tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) and triphenyl phosphate (TPhP) in rat (INS1E) and human (NES2Y) pancreatic beta-cell lines. One-week exposure to 1 μM and 10 μM TDCIPP and TPhP altered intracellular insulin and proinsulin levels, but not the levels of secreted insulin (despite the presence of a statistically insignificant trend). The exposures also altered the protein expression of several factors involved in beta-cell metabolic pathways and signaling, including ATP citrate lyase, isocitrate dehydrogenase 1, perilipins, glucose transporters, ER stress-related factors, and antioxidant enzymes. This study has brought new and valuable insights into the toxicity of TDCIPP and TPhP on beta-cell function and revealed alterations that might impact insulin secretion after more extended exposure. It also adds to the scarce studies using in vitro pancreatic beta-cells models in toxicological testing, thereby promoting the development of non-animal testing strategy for identifying pro-diabetic effects of chemical pollutants.

Widespread occurrence of pesticides in low-income housing

BACKGROUND

Low socioeconomic status (SES) residents living in social housing, which is subsidized by government or government-funded agencies, may have higher exposures to pesticides used in indoor residences since pesticides are applied due to structural deficiencies, poor maintenance, etc. OBJECTIVE: To estimate exposure of residents in low-SES social housing built in the 1970s to legacy and current-use pesticides and to investigate factors related to exposures.

METHODS

Twenty-eight particle-phase pesticides were measured in the indoor air of 46 units in seven low-income social housing, multi-unit residential buildings (MURBs) in Toronto, Canada using portable air cleaners deployed for 1 week in 2017. Pesticides analyzed were legacy and current use in the classes: organochlorines, organophosphates, pyrethroids, and strobilurins.

RESULTS

At least one pesticide was detected in 89% of the units with detection frequencies (DF) for individual pesticides of up to 50%, including legacy organochlorines and current-use pesticides. Current-use pyrethroids had the highest DF and concentrations, with the highest particle-phase concentration for pyrethrin I at 32,000 pg/m3. Heptachlor, restricted for use in Canada in 1985, had the highest estimated maximum total air (particle plus gas phase) concentration of 443,000 pg/m3. Heptachlor, lindane, endosulfan I, chlorothalonil, allethrin, and permethrin (except in one study) had higher concentrations than those measured in low-income residences reported elsewhere. In addition to the intentional use of pesticides to control pests and their use in building materials and paints, tobacco smoking was significantly correlated with the concentrations of five pesticides used on tobacco crops. The distribution of pesticides with high DF in individual buildings suggested that pest eradication programs by the building management and/or pesticide use by residents were the major sources of measured pesticides.

IMPACT

Low-income social housing fills a much-needed demand, but the residences are prone to pest infestation and hence pesticide use. We found exposure to at least 1 of 28 particle-phase pesticides in 89% of all 46 units tested, with the highest DF and concentrations for current-use pyrethroids and long-banned organochlorines (e.g., DDT, heptachlor) due to very high persistence indoors. Also measured were several pesticides not registered for use indoors, e.g., strobilurins used to treat building materials and pesticides used on tobacco crops. These results, which are the first Canadian data for most pesticides indoors, show widespread exposure to numerous pesticides.

Three strategy rules of filamentous fungi in hydrocarbon remediation: an overview

Remediation of hydrocarbon contaminations requires much attention nowadays since it causes detrimental effects on land and even worse impacts on aquatic environments. Tools of bioremediation especially filamentous fungi permissible for cleaning up as much as conceivable, at least they turn into non-toxic residues with less consumed periods. Inorganic chemicals, CO2, H2O, and cell biomass are produced as a result of the breakdown and mineralization of petroleum hydrocarbon pollutants. This paper presents a detailed overview of three strategic rules of filamentous fungi in remediating the various aliphatic, and aromatic hydrocarbon compounds: utilizing carbons from hydrocarbons as sole energy, Co-metabolism manners (Enzymatic and Non-enzymatic theories), and Biosorption approaches. Upliftment in the degradation rate of complex hydrocarbon by the Filamentous Fungi in consortia scenario we can say, "Fungal Talk", which includes a variety of cellular mechanisms, including biosurfactant production, biomineralization, and precipitation, etc., This review not only displays its efficiency but showcases the field applications - cost-effective, reliable, eco-friendly, easy to culture as biomass, applicable in both land and any water bodies in operational environment cleanups. Nevertheless, the potentiality of fungi-human interaction has not been fully understood, henceforth further studies are highly endorsed with spore pathogenicity of the fungal species capable of high remediation rate, and the gene knockout study, if the specific peptides cause toxicity to any living matters via Genomics and Proteomics approaches, before application of any in situ or ex situ environments.

Novel halogenated flame retardants in Canadian human milk from the MIREC study (2008-2011)

Novel halogenated flame retardants (NHFRs) have been developed to replace those brominated flame retardants that have been restricted due to their persistence, bioaccumulation potential and toxicity, therefore, it is important to determine whether these replacement products are present at detectable concentrations in Canadians. NHFRs were measured in human milk samples (n = 541) collected from across Canada between 2008 and 2011, which is the first pan-Canadian dataset for these chemicals in human milk. Among the 15 measured NHFRs and eight methoxy-polybrominated diphenyl ethers (MeO-PBDEs), nine NHFRs and two MeO-PBDEs (6-MeO-PBDE 47 and 2-MeO-PBDE 68) were detected at a frequency of more than 9%. Despite benzene, 1,1'-(1,2-ethanediyl)bis [2,3,4,5,6-pentabromo-]/decabromodiphenylethane [DBDPE] being detected less frequently than the other observed NHFRs, its relative contribution to the sum of nine NHFRs was important when it was present. The maximum ΣNHFR concentration in Canadian human milk was 6930 pg g-1 lipid while the maximum ΣMeO-PBDEs was 1600 pg g-1 lipid. While most NHFR concentrations were significantly correlated with each other, no relationships between maternal age, parity or pre-pregnancy BMI were identified with ΣNHFR concentrations in the milk. In contrast, maternal age was significantly correlated with ΣMeO-PBDE concentrations (r = 0.237, p < 0.001). ΣNHFR concentrations were similarly not related to maternal education, although ΣMeO-PBDE concentrations were found to be higher in milk from women who had graduated from trade schools relative to the other education levels considered. NHFR detection frequency and concentrations observed in the Canadian human milk seem to align well with Europe.

Anti-androgenic activity of novel flame retardants in mixtures: Newly identified contribution from tris(2,3-dibromopropyl) isocyanurate (TDBP-TAZTO)

In recent decades, male infertility has been on the rise, largely attributed to exposure to chemicals with endocrine-disrupting properties. The adverse effects of disrupting androgen actions on the development and reproductive health of children and adolescents have been extensively studied. Flame retardants (FRs), used in consumer products to delay flammability, have been identified as antagonists of the androgen receptor (AR), potentially leading to adverse outcomes in male reproductive health later in life. This study examined the interaction of eight novel FRs with the AR, employing an in vitro AR-dependent luciferase reporter gene assay utilizing MDA-kb2 cells. The investigation revealed the anti-androgenic activity of tris(2,3-dibromopropyl) isocyanurate (TDBP-TAZTO), a frequently detected FR in the environment. Furthermore, TDBP-TAZTO contributed to anti-androgenic activity when combined with six other anti-androgenic FRs. The mixture effects were predicted by three commonly employed models: concentration addition (CA), generalized CA, and independent action, with the CA model showcasing the highest accuracy. This suggests that all FRs act through a similar mechanism, as further confirmed by in silico molecular docking, indicating limited synergy or antagonism. Importantly, in the mixtures, each FR contributed to the induction of anti-androgenic effects at concentrations below their individual effective concentrations in single exposures. This raises concern for public health, especially considering the co-detection of these FRs and their potential co-occurrence with other anti-androgenic chemicals like bisphenols. Therefore, our findings, along with previous research, strongly support the incorporation of combined effects of mixtures in risk assessment to efficiently safeguard population health.

Repeated Human Exposure to Semivolatile Organic Compounds by Inhalation: Novel Protocol for a Nonrandomized Study

BACKGROUND

Semivolatile organic compounds (SVOCs) comprise several different chemical families used mainly as additives in many everyday products. SVOCs can be released into the air as aerosols and deposit on particulate matter during use by dispersion, evaporation, or abrasion. Phthalates are SVOCs of growing concern due to their endocrine-disrupting effects. Human data on the absorption, distribution, metabolism, and excretion (ADME) of these compounds upon inhalation are almost nonexistent.

OBJECTIVE

The goal of this study is to develop a method for repeated inhalation exposures to SVOCs to characterize their ADME in humans.

METHODS

We will use diethylhexyl phthalate (DEHP), a major indoor air pollutant, as a model SVOC in this novel protocol. The Swiss official Commission on Ethics in Human Research, Canton de Vaud, approved the study on October 14, 2020 (project-ID 2020-01095). Participants (n=10) will be repeatedly exposed (2 short daily exposures over 4 days) to isotope-labeled DEHP (DEHP-d4) to distinguish administered exposures from background exposures. DEHP-d4 aerosols will be generated with a small, portable, aerosol-generating device. Participants will inhale DEHP-d4-containing aerosols themselves with this device at home. Air concentrations of the airborne phthalates will be less than or equal to their occupational exposure limit (OEL). DEHP-d4 and its metabolites will be quantified in urine and blood before, during, and after exposure.

RESULTS

Our developed device can generate DEHP-d4 aerosols with diameters of 2.5 μm or smaller and a mean DEHP-d4 mass of 1.4 (SD 0.2) μg per puff (n=6). As of May 2023, we have enrolled 5 participants.

CONCLUSIONS

The portable device can be used to generate phthalate aerosols for repeated exposure in human studies.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/51020.

Association between polychlorinated biphenyls exposure and incident type 2 diabetes mellitus: A nested case-control study

BACKGROUND

Previous epidemiological studies indicated that the association between polychlorinated biphenyls (PCB) and type 2 diabetes mellitus (T2DM) was inconclusive.

OBJECTIVE

We investigated the association between PCBs exposure and incident T2DM in a nested case-control study, and further explored the relationship between PCBs and 5-year fasting blood glucose (FBG) changes.

METHODS

Baseline concentrations of seven indicator-PCB (PCB-28, 52, 101, 118, 138, 153, 180) were measured in 1006 pairs of incident T2DM cases and matched controls nested within the Dongfeng-Tongji cohort. Conditional logistic regression models and pre-adjusted residuals method were used to assess the associations between PCBs and incident T2DM. We further computed beta coefficients (βs) of 5-year FBG changes using multivariable generalized linear regression.

RESULTS

Non-dioxin-like PCBs (NDL-PCBs) were significantly associated with higher T2DM incidence after adjustment for all covariates. Significant differences were observed for extreme quartiles comparisons (Q4 vs. Q1) of PCBs except PCB-138, and the incidence of T2DM were 1- to 3-fold higher among those in the highest versus lowest PCBs quartiles. Serum NDL-PCBs were positively associated with changes in FBG (P for overall association ≤0.01). Additionally, triglycerides mediated the associations between PCBs and T2DM incidence.

CONCLUSION

Our findings showed positive associations of NDL-PCBs with incident T2DM and 5-year FBG changes. PCBs increased incident T2DM via lipid metabolic pathways.

Gas-Particle Partitioning of Semivolatile Organic Compounds in a Residence: Influence of Particles from Candles, Cooking, and Outdoors

Semivolatile organic compounds (SVOCs) represent an important class of indoor pollutants. The partitioning of SVOCs between airborne particles and the adjacent air influences human exposure and uptake. Presently, little direct experimental evidence exists about the influence of indoor particle pollution on the gas-particle phase partitioning of indoor SVOCs. In this study, we present time-resolved gas- and particle-phase distribution data for indoor SVOCs in a normally occupied residence using semivolatile thermal desorption aerosol gas chromatography. Although SVOCs in indoor air are found mostly in the gas phase, we show that indoor particles from cooking, candle use, and outdoor particle infiltration strongly affect the gas-particle phase distribution of specific indoor SVOCs. From gas- and particle-phase measurements of SVOCs spanning a range of chemical functionalities (alkanes, alcohols, alkanoic acids, and phthalates) and volatilities (vapor pressures from 10^-13 to 10^-4 atm), we find that the chemical composition of the airborne particles influences the partitioning of individual SVOC species. During candle burning, the enhanced partitioning of gas-phase SVOCs to indoor particles not only affects the particle composition but also enhances surface off-gassing, thereby increasing the total airborne concentration of specific SVOCs, including diethylhexyl phthalate.

A review of critical residential buildings parameters and activities when investigating indoor air quality and pollutants

Indoor air in residential dwellings can contain a variety of chemicals, sometimes present at concentrations or in combinations which can have a negative impact on human health. Indoor Air Quality (IAQ) surveys are often required to characterize human exposure or to investigate IAQ concerns and complaints. Such surveys should include sufficient contextual information to elucidate sources, pathways, and the magnitude of exposures. The aim of this review was to investigate and describe the parameters that affect IAQ in residential dwellings: building location, layout, and ventilation, finishing materials, occupant activities, and occupant demography. About 180 peer-reviewed articles, published from 01/2013 to 09/2021 (plus some important earlier publications), were reviewed. The importance of the building parameters largely depends on the study objectives and whether the focus is on a specific pollutant or to assess health risk. When considering classical pollutants such as particulate matter (PM) or volatile organic compounds (VOCs), the building parameters can have a significant impact on IAQ, and detailed information of these parameters needs to be reported in each study. Research gaps and suggestions for the future studies together with recommendation of where measurements should be done are also provided.

Application of a pharmacokinetic model in characterizing sources of polychlorinated biphenyl exposure and determining threshold daily intakes for adverse health effects in infants and toddlers

Characterization of PCB exposure sources for vulnerable population groups is essential to minimize the health effects of PCB exposure. At the same time, it is important to consolidate the knowledge on threshold intakes of PCBs for infants and toddlers to prevent health effects. We estimated total PCB concentrations from birth to 2 years of age in children from Slovak and Czech populations, which continue to have high PCB concentrations in breast milk. Using a pharmacokinetic (PK) model, we characterized dominant PCB exposure sources and estimated new threshold estimated daily intakes (TEDI) (above which adverse effects cannot be excluded) for postnatal PCB exposure in infants and toddlers. In the PK model, concentrations of seven indicator PCBs in breast milk and cord blood samples from 291 mother-child pairs from the Slovak birth cohort, and 396 breast milk samples from Czech mothers we used, together with their physiological characteristics and PCB concentrations from other exposure sources (food, dust, air). The estimated total PCB concentrations in children's blood at different ages were compared with threshold PCB concentrations of 500, 700 and 1000 ng·g_lipid^-1 in serum proposed by the French Agency for Food, Environmental and Occupational Health & Safety (ANSES) and the German Environment Agency (UBA), above which possible adverse health effects may be expected. We estimated that up to 20.6% of Slovak children and up to 45.7% of Czech children at two years of age exceeded the threshold value of 700 ng·g_lipid^-1 in blood. Mean TEDIs leading to values of 500 ng·g_lipid^-1 in blood for children up to two years ranged between 110 and 220 ng·kg^-1·bw·day^-1, varying according to breastfeeding duration. Breast milk and prenatal exposure contributed to 71%-85% of PCBs exposure at two years of age. In contrast, the contributions of PCBs from dust and indoor air were negligible.

Legacy halogenated organic contaminants in urban-influenced waters using passive polyethylene samplers: Emerging evidence of anthropogenic land-use-based sources and ecological risks

Legacy halogenated organic pollutants, including organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs), remain ubiquitous in the environment and continue to pose potential (eco-)toxicological threats because of their ongoing releases from land-based sources. This study investigated the spatial trends of freely dissolved PCBs and OCPs by polyethylene passive samplers, and provided evidence of their land-use-based sources and ecological risk in an urbanized estuary area of Narragansett Bay. Dissolved Σ₂₉PCB concentrations ranged from 0.01 to 1.37 ng L^-1, and exhibited higher concentrations in the upper, more urban/built-up watershed, and in north coastal areas. Major inputs of PCBs were urban stormwater or treated wastewater that might carry past releases of Aroclors, pigment manufacturing byproducts, and volatilization-associated PCBs from ageing buildings from the Narragansett watershed to the bay. The dioxin toxicity equivalent values of Σ₅PCBs were 8.6E-03 pg L^-1 in water. Dissolved OCP concentrations had similar spatial trends to PCBs and were dominated by DDTs (average 230 pg L^-1), followed by chlordanes (average 230 pg L^-1), and HCB (average 22 pg L^-1). Secondary sources of past usage and historic contamination were expected to re-enter the surface water via atmospheric transport and deposition. The risk quotients of DDE, DDD, DDT and α-Endosulfane showed medium to high ecological risks in the northern area, while chlordane, HCB, oxychlordane, and heptachlor epoxide showed low to negligible risks in all zones. This study presented new insights into the presence, sources and transport of legacy halogenated organic contaminants in an urban estuary's watershed by combining passive samplers and geographic information system (GIS) technology. The approach is promising and could be extended to get better understand of terrestrial pollutant mobilization into estuaries affected by anthropogenic activities.

Indoor exposure to phthalates and polycyclic aromatic hydrocarbons (PAHs) to Canadian children: the Kingston allergy birth cohort

BACKGROUND

Canadian children are widely exposed to phthalates and polycyclic aromatic hydrocarbons (PAHs) from indoor sources. Both sets of compounds have been implicated in allergic symptoms in children.

OBJECTIVE

We characterize concentrations of eight phthalates and 12 PAHs in floor dust from the bedrooms of 79 children enrolled in the Kingston Allergy Birth Cohort (KABC).

METHOD

Floor dust was collected from the bedrooms of 79 children who underwent skin prick testing for common allergens after their first birthday. Data were collected on activities, household, and building characteristics via questionnaire.

RESULTS

Diisononyl phthalate (DiNP) and phenanthrene were the dominant phthalate and PAH with median concentrations of 561 µg/g and 341 ng/g, respectively. Benzyl butyl phthalate (BzBP) and chrysene had the highest variations among all tested homes, ranging from 1-95% to 1-99%, respectively.

SIGNIFICANCE

Some phthalates were significantly associated with product and material use such as diethyl phthalate (DEP) with fragranced products and DiNP and DiDP with vinyl materials. Some PAHs were significantly associated with household characteristics, such as benzo[a]pyrene with smoking, and phenanthrene and fluoranthene with the presence of an attached garage. Socioeconomic status (SES) had positive and negative relationships with some concentrations and some explanatory factors. No significant increases in risk of atopy (positive skin prick test) was found as a function of phthalate or PAH dust concentrations.

Exploring personal chemical exposures in China with wearable air pollutant monitors: A repeated-measure study in healthy older adults in Jinan, China

The health impact of airborne contaminants has been challenging to assess due to current limitations in measurement technologies. The emergence of wearable passive samplers coupled with high resolution mass spectrometry (HR-MS) chemical analysis has enabled comprehensive characterization of personal exposures. We conducted a repeated-measure study among 84 older adults in Jinan, China, as part of the Biomarkers for Air Pollutants Exposure (China BAPE) study. Study objectives were: 1) to characterize the occurrence, magnitude, and distribution of personal exposure to airborne contaminants; 2) to evaluate the temporal variation of chemical exposures across the study population; and 3) to identify behavioral and environmental factors that influence the observed variance in chemical exposures. The FreshAir wristband was worn by participants for three consecutive days each month from September 2018 to January 2019 and collected with paired time-activity logs. Passive air samplers were also deployed in parallel at a local outdoor air monitoring station. Spearman's Rho trend test and trajectory cluster analysis were used to identify exposure trends and variation patterns, respectively. Out of the 70 airborne compounds of potential concern screened, 26 compounds from 10 chemical classes were found to be above detection thresholds across >70% of the study population. Personal exposures were predominantly characterized by nine polycyclic aromatic hydrocarbons (PAHs), four phthalates, three nitroaromatics, and two volatile organic compounds (VOCs). Phthalate personal exposures were positively correlated with outdoor temperatures while the inverse relationship was observed for certain PAHs (p < 0.05). Specifically, dimethyl phthalate (r_s = 0.31) decreased as temperatures declined, while nitrobenzene (r_s = -0.35) and naphthalene (r_s = -0.40) increased as temperatures decreased. Compared to levels measured at the outdoor air monitoring site, personal exposure of phthalates was elevated (p < 0.05) and hexachlorobutadiene was lower across participants (p < 0.01). Personal exposure of these chemicals was further found to be weakly associated with daily duration participants spent outdoors. Individuals formed distinct clusters based on trajectories of chemical exposures across the sampling period (September to January), potentially suggestive of distinct emission sources. In conclusion, we demonstrate the feasibility of characterizing the occurrence and magnitude of personal exposure to airborne chemical contaminants using passive wristband samplers. The temporal variability of these personal exposure profiles was highlighted and with distinct trends identified across different groups of individuals. Future studies will integrate this data with other omics datasets collected from this population of Chinese older adults to investigate associations between exposure profiles and health relevant biomarkers, to provide evidence in feasibility of disease prevention through environmental improvements.

Textile Washing Conveys SVOCs from Indoors to Outdoors: Application and Evaluation of a Residential Multimedia Model

Indoor environments have elevated concentrations of numerous semivolatile organic compounds (SVOCs). Textiles provide a large surface area for accumulating SVOCs, which can be transported to outdoors through washing. A multimedia model was developed to estimate advective transport rates (fluxes) of 14 SVOCs from indoors to outdoors by textile washing, ventilation, and dust removal/disposal. Most predicted concentrations were within 1 order of magnitude of measurements from a study of 26 Canadian homes. Median fluxes to outdoors [μg·(year·home)^-1] spanned approximately 4 orders of magnitude across compounds, according to the variability in estimated aggregate emissions to indoor air. These fluxes ranged from 2 (2,4,4'-tribromodiphenyl ether, BDE-28) to 30 200 (diethyl phthalate, DEP) for textile washing, 12 (BDE-28) to 123 200 (DEP) for ventilation, and 0.1 (BDE-28) to 4200 (bis(2-ethylhexyl) phthalate, DEHP) for dust removal. Relative contributions of these pathways to the total flux to outdoors strongly depended on physical-chemical properties. Textile washing contributed 20% tris-(2-chloroisopropyl)phosphate (TCPP) to 62% tris(2-butoxyethyl)phosphate (TBOEP) on average. These results suggest that residential textile washing can be an important transport pathway to outdoors for SVOCs emitted to indoor air, with implications for human and ecological exposure. Interventions should try to balance the complex tradeoff of textile washing by minimizing exposures for both human occupants and aquatic ecosystems.

Targeted and suspect screening of plasticizers in house dust to assess cumulative human exposure risk

Indoor dust is an important exposure route to anthropogenic chemicals used in consumer products. Plasticizers are common product additives and can easily leach out of the product and partition to dust. Investigations of plasticizers typically focus on a subset of phthalate esters (PEs), but there are many more PEs in use, and alternative plasticizers (APs) are seeing greater use after recognition of adverse health effects of PEs. In this study we use full scan high resolution mass spectrometry for targeted and suspect screening of PEs and APs in house dust and to assess the potential risk of human exposure. House dust samples from Eastern Slovakia were investigated and concentrations of ∑₁₂PEs and ∑₅APs ranged 12-2765 μg/g and 45-13,260 μg/g, respectively. APs were at similar levels to PEs, indicating common usage of these compounds in products in homes. Evaluation of individual compound toxicity combined with human intake via dust ingestion suggested PEs are of lower priority compared to semivolatile organic compounds such as polychlorinated biphenyls due to their lower toxicity. However, cumulative risk assessment (CRA) is a more appropriate evaluation of risk, considering the presences of many PEs in dust and their similar toxic mode of action. CRA based on median toxicity reference values (TRVs) suggested acceptable risks for dust ingestion, however, the wide range of literature-derived TRVs is a large uncertainty, especially for the APs. Use of newer TRVs suggest risk from dust ingestion alone, i.e. not even considering diet, inhalation, and dermal contact. Additionally, screening of full-scan instrumental spectra identified a further 40 suspect PE compounds, suggesting the CRA based on the 12 target PEs underestimates the risk.

Endocrine disrupting potential of replacement flame retardants - Review of current knowledge for nuclear receptors associated with reproductive outcomes

BACKGROUND AND AIM

Endocrine disrupting chemicals (EDCs) constitute a major public health concern because they can induce a large spectrum of adverse effects by interfering with the hormonal system. Rapid identification of potential EDCs using in vitro screenings is therefore critical, particularly for chemicals of emerging concerns such as replacement flame retardants (FRs). The review aimed at identifying (1) data gaps and research needs regarding endocrine disrupting (ED) properties of replacement FRs and (2) potential EDCs among these emerging chemicals.

METHODS

A systematic search was performed from open literature and ToxCast/Tox21 programs, and results from in vitro tests on the activities of 52 replacement FRs towards five hormone nuclear receptors (NRs) associated with reproductive outcomes (estrogen, androgen, glucocorticoid, progesterone, and aryl hydrocarbon receptors) were compiled and organized into tables. Findings were complemented with information from structure-based in silico model predictions and in vivo information when relevant.

RESULTS

For the majority of the 52 replacement FRs, experimental in vitro data on activities towards these five NRs were either incomplete (15 FRs) or not found (24 FRs). Within the replacement FRs for which effect data were found, some appeared as candidate EDCs, such as triphenyl phosphate (TPhP) and tris(1,3-dichloropropyl)phosphate (TDCIPP). The search also revealed shared ED profiles. For example, anti-androgenic activity was reported for 19 FRs and predicted for another 21 FRs.

DISCUSSION

This comprehensive review points to critical gaps in knowledge on ED potential for many replacement FRs, including chemicals to which the general population is likely exposed. Although this review does not cover all possible characteristics of ED, it allowed the identification of potential EDCs associated with reproductive outcomes, calling for deeper evaluation and possibly future regulation of these chemicals. By identifying shared ED profiles, this work also raises concerns for mixture effects since the population is co-exposed to several FRs and other chemicals.

Ecological and human health risk assessment of total petroleum hydrocarbons in surface water and sediment from Woji Creek in the Niger Delta Estuary of Rivers State, Nigeria

This study was designed to assess total petroleum hydrocarbon (THP) concentrations in the surface water and sediment sampled from Woji Creek and to assess potential ecological and human health risk due to petroleum hydrocarbons along the creek. Physicochemical parameters [pH, temperature (T), electrical conductivity (EC), dissolved oxygen (DO), total dissolved solids (TDS)] were in-situ measured from sediment and surface water; hydrological parameters (width, depth and volume) were used to calculate the flow rate (discharge) at different stations of the creek. Trend of TPH in the surface water samples along the creek were as follows: St4 (3.639 ± 1.121 mg/L) > St3 (2.449 ± 0.623 mg/L) > St1 (1.457 ± 0.244 mg/L) > St2 (1.069 ± 0.228 mg/L) > St5 (1.010 ± 0.120 mg/L) Trend of TPH concentration across the creek was as follows: St1 - 8.758 ± 0.697 mg/kg > St3 - 7.675 ± 0.541 mg/kg > St5 - 5.515 ± 0.401 mg/kg > St4 - 5.075 ± 0.363 mg/kg > St2 - 3.162 ± 0.307 mg/kg. Diagnostic indices indicate that the hydrocarbon in the creek was from petrogenic source. Estimation of ecological risk indicated risk in the surface water but not in the sediment. However, human health risk assessment indicated no risk due to human ingestion of the sediment or surface water.

Organochlorine pesticides (OCPs) in air-conditioner filter dust of indoor urban setting: Implication for health risk in a developing country

This preliminary investigation highlights the occurrence of organochlorine pesticides (OCPs) in the indoor environment of a megacity, Lahore, Pakistan using the dust ensnared by air-conditioner filters. The Σ₁₆ OCPs concentration ranged from 7.53 to 1272.87 ng/g with the highest percent contribution by ΣDDT (dichlorodiphenyltrichloroethane; 87.21%) and aldrin (6.58%). The spatial variation of OCPs profile revealed relatively higher concentration from homes near to agricultural and abandoned DDT manufacturing sites. Calculated isomer ratios revealed historic sources of hexachlorocyclohexanes (HCHs) and the fresh input of technical DDT and chlordane by the dwellers. The air conditioner dust was helpful to better understand the health risk in the indoor environment. So far a high lifetime cancer risk (10^-3 ) was predicted for toddlers via accidental ingestion, inhalation, and dermal exposure. Similarly, the non-carcinogenic risk-based hazard quotient was found to be high for toddlers (6.94) and within the permissible limit (<1) for adults.

Emerging investigator series: air conditioning filters as a sampler for semi-volatile organic compounds in indoor and near-building air

Organic compounds like flame retardants (FRs), polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs) and polycyclic aromatic hydrocarbons (PAHs) are consistently found in both indoor and outdoor environments. There are many possible matrices for measurement of these compounds (e.g. indoor dust, air - passive and active air samples), but all methods have limitations, like the heterogeneous distribution of indoor dust, or noisy active air samplers. We used filters from building-wide heating, ventilation and air conditioning (HVAC) units to evaluate levels of PAHs, PCBs, OCPs and NFRs in indoor and outdoor environments, and to evaluate whether this method is feasible for screening semivolatile organic compounds (SVOCs) in indoor and near-building outdoor environments. Detectable levels of FRs, PCBs, OCPs and PAHs were found, demonstrating that HVAC filters do collect SVOCs, with generally higher levels of PAHs in the incoming air filters and higher levels of PCBs, OCPs and FRs in the outgoing air filters. Levels of FRs, PCBs and OCPs in outgoing air were comparable to those measured using conventional active air sampling in the same building. The advantages of using HVAC filters are (1) integrated and homogeneous samples, as the whole building is sampled over typically a long timescale (months), and (2) samples are easy and cheap to collect and do not require prior deployment of samplers. The key disadvantage is that HVAC filters are not designed for analytical chemistry and thus the filter materials can have variable or unknown gas sorption and particle capture, and can have strong matrix effects during analysis.

Investigating the presence of emerging and legacy POPs in European domestic air

Presence of organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and dechlorane plus (DP) were evaluated in indoor domestic air from four European countries (Belgium, Italy, Spain and Portugal). The main pollutants were hexachlorohexanes (sum of α-, β- and γ-HCH; ΣHCHs) and ΣPCBs (sum of PCB-28, 52, 101, 118, 138, 153 and 180), with median concentrations of 366 and 306 pg/m³, respectively. By decreasing order came hexachlorobenzene (HCB; 130 pg/m³), ΣDDXs (sum of DDTs, DDEs and DDDs; 94.4 pg/m³), ΣPBDEs (sum of BDE-17, 28, 47, 66, 99, 100, 153, 154, 183, 206, 207 and 209; 6.08 pg/m³) and DP (0.30 pg/m³). Lower ΣPCBs and ΣDDXs levels were found at Portuguese homes compared to Belgian, Italian and Spanish households. Italian samples presented also lower ΣHCHs concentrations while Spanish homes revealed higher HCB and BDE-209 indoor air concentrations than those obtained in the other countries. ΣHCHs, ΣDDXs and ΣPBDE levels mirrored lindane, dicofol and Penta-, DecaBDE use, respectively. The influence of building characteristics, surroundings and inhabitants habits on pollutant air concentrations was investigated. Data generated were used to conduct a human exposure assessment for toddlers and adults with median (P50) and upper (P95) concentrations. Results indicated that health risk posed by inhalation of ΣPCBs, ΣHCHs, ΣDDXs, HCB, ΣPBDEs and DP were 2 to 5 orders of magnitude lower than oral Reference Dose (RfD) values, and 90 (PCB-28) and 12 (γ-HCH) times lower than Minimal Risk Levels (MRLs) for toddlers at the worst case scenario.

Pet hair as a potential sentinel of human exposure: Investigating partitioning and exposures from OPEs and PAHs in indoor dust, air, and pet hair from China

We investigated the levels, compositions, and partitioning behaviors of organophosphate esters (OPEs) and polycyclic aromatic hydrocarbons (PAHs) in indoor air, dust, and pet hair from North China, as well as their potential exposures for humans and pets. The mean OPE concentrations in the indoor air (n = 19), dust (n = 26), and pet hair (n = 29) samples were 52.1 ng/m³, 3510 ng/g, and 1440 ng/g; while the mean PAH concentrations were 369 ng/m³, 6000 ng/g, and 22.6 ng/g, respectively. The matrix-air partitioning of OPEs and PAHs may reach equilibrium for compounds with octanol-air partition coefficients (logK_oa) between 7 and 11 for dust and logK_oa < 12 for pet hair. Correlation analysis suggested that pet hair could be used as a sentinel for the exposure to certain PAHs, e.g., phenanthrene (PHE) or fluoranthene (FLA), via exposure to indoor air. This work suggests that pet hair may be a better sentinel than air and dust for human exposure to OPEs and PAHs across different indoor microenvironments. Estimated daily intakes (EDIs) to OPEs and PAHs via air inhalation, dust ingestion, and dermal absorption were calculated for children, adults, and pets. The median ΣEDIs for children, adults, and pets were 26.7, 5.40, and 55.0 ng/kg/day for ΣOPEs, and 68.8, 19.1, and 130 ng/kg/day for ΣPAHs, respectively. Air inhalation was the main exposure route to PAHs and OPEs with logK_oa < 10, whereas dust ingestion was the main exposure route to those with logK_oa > 10.

Direct immersion single-drop microextraction of semi-volatile organic compounds in environmental samples: A review

Single-drop microextraction (SDME) techniques are efficient approaches to pretreatment of aqueous samples. The main advantage of SDME lies in the miniaturization of the solvent extraction process, minimizing the hazards associated with the use of toxic organic solvents. Thus, SDME techniques are cost-effective, and represent less harm to the environment, subscribing to green analytical chemistry principles. In practice, two main approaches can be used to perform SDME - direct immersion (DI)-SDME and headspace (HS)-SDME. Even though the DI-SDME has been shown to be quite effective for extraction and enrichment of various organic compounds, applications of DI-SDME are normally more suitable for moderately polar and non-polar semi-volatile organic compounds (SVOCs) using organic solvents which are immiscible with water. In this review, we present a historical overview and current advances in DI-SDME, including the common analytical tools which are usually coupled with DI-SDME. The review also focuses on applications concerning SVOCs in environmental samples. Currents trends in DI-SDME and possible future direction of the procedure are discussed.

A needle trap device method for sampling and analysis of semi-volatile organic compounds in air

Semi-volatile organic compounds (SVOCs), such as phthalates, organophosphates, and polybrominated diphenyl ethers, are emerging as an important class of pollutants that are of serious health concerns. Determining concentrations of these pollutants is of great importance for environmental and exposure studies. In this work, a needle trap device (NTD) method was developed to measure the concentration of SVOCs in air samples. Sorbents were packed in the NTD to capture SVOCs with the aid of a sampling pump. NTD operational parameters, such as desorption temperature, desorption time, and sampling flow rate, were optimized for the target SVOCs. The limit of detection for air sampling by the NTD method ranged between 5 pg and 1 ng, depending on the SVOC compound. The variations in terms of NTD repeatability and reproducibility were lower than 14% for all cases. In addition, the influence of other experimental parameters, such as sampling temperature and humidity, breakthrough volume, NTD storage time, as well as carryover effect were examined. Finally, NTDs were used to determine emissions of gas-phase SVOCs from various consumer products in an emission cell and to collect total airborne SVOC samples (gas and particle phases) in an office. The results of NTD method were in an agreement with data obtained by conventional active sampling methods using Tenax® sorbent tubes and polyurethane foam samplers, but with improvements of relative standard deviation, sensitivity, and sampling time. The results demonstrated that the NTD method is a simple, sensitive, effective, reusable, and inexpensive technique for sampling and analyzing SVOCs in the concentration range from 2 ng m^-3 to 100 μg m^-3 in air.