Accumulation of gas‐phase methamphetamine on clothing,toy fabrics,and skin oil

To better understand methamphetamine exposure and risk for occupants of former residential clandestine methamphetamine laboratories, we measured the dynamic accumulation of methamphetamine in skin oil, cotton and polyester (PE) clothing, upholstery, and toy fabric (substrates) exposed to 15–30 ppb (91–183 μg/m³) neutral methamphetamine in air for up to 60 days. The average equilibrium partition coefficients at 30% RH, in units of μg of methamphetamine per gram of substrate per ppb, are 3.0 ± 0.2 for a PE baby blanket, 5.6 ± 3.5 for a PE fabric toy, 3.7 ± 0.2 for a PE shirt, 18.3 ± 8.0 for a PE/cotton upholstery fabric, and 1200 ± 570 in skin oil. The partition coefficients at 60% RH are 4.5 ± 0.4, 5.2 ± 2.1, 4.5 ± 0.6, 36.1 ± 3.6, and 1600 ± 1100 μg/(g ppb), respectively. There was no difference in the partition coefficient for a clean and skin‐oil‐soiled cotton shirt [15.3 ± 2.1 μg/(g ppb) @ 42 days]. Partition coefficients for skin oil may be sensitive to composition. ‘Mouthing’ of cloth is predicted to be the dominant exposure pathway [60 μg/(kg body weight*ppb)] for a toddler in former meth lab, and indoor air concentrations would have to be very low (0.001 ppb) to meet the recommended reference dose for children.     

Mono‐, di‐, and trichlorinated biphenyls (PCB 1‐PCB 39) in the indoor air of office rooms and their relevance on human blood burden

Exposure to polychlorinated biphenyls (PCBs) from indoor air can lead to a significant increase in lower chlorinated congeners in human blood. Lower chlorinated congeners with short biological half‐lives can exhibit an indirect genotoxic potential via their highly reactive metabolites. However, little is known about their occurrence in indoor air and, therefore, about the effects of possible exposure to these congeners. We analyzed all mono‐, di‐, and trichlorinated biphenyls in the indoor air of 35 contaminated offices, as well as in the blood of the 35 individuals worked in these offices for a minimum of 2 years. The median concentration of total PCB in the indoor air was 479 ng/m³. The most prevalent PCBs in the indoor air samples were the trichlorinated congeners PCB 31, PCB 18, and PCB 28, with median levels of 39, 31, and 26 ng/m³, respectively. PCB 8 was the most prevalent dichlorinated congener (median: 9.1 ng/m³). Monochlorinated biphenyls were not detected in relevant concentrations. In the blood samples, the most abundant congener was PCB 28; nearly 90% of all mono‐, di‐, and trichlorinated congeners were attributed to this congener (median: 12 ng/g blood lipid).     

From air to clothing: characterizing the accumulation of semi‐volatile organic compounds to fabrics in indoor environments

Uptake kinetics of semi‐volatile organic compounds (SVOCs) present indoors, namely phthalates and halogenated flame retardants (HFRs), were characterized for cellulose‐based cotton and rayon fabrics. Cotton and rayon showed similar accumulation of gas‐ and particle‐phase SVOCs, when normalized to planar surface area. Accumulation was 3–10 times greater by rayon than cotton, when normalized to Brunauer–Emmett–Teller (BET) specific surface area which suggests that cotton could have a longer linear uptake phase than rayon. Linear uptake rates of eight consistently detected HFRs over 56 days of 0.35–0.92 m³/day.dm² planar surface area and mass transfer coefficients of 1.5–3.8 m/h were statistically similar for cotton and rayon and similar to those for uptake to passive air sampling media. These results suggest air‐side controlled uptake and that, on average, 2 m² of clothing typically worn by a person would sequester the equivalent of the chemical content in 100 m³ of air per day. Distribution coefficients between fabric and air (K′) ranged from 6.5 to 7.7 (log K′) and were within the range of partition coefficients measured for selected phthalates as reported in the literature. The distribution coefficients were similar for low molecular weight HFRs, and up to two orders of magnitude lower than the equilibrium partition coefficients estimated using the COSMO‐RS model. Based on the COSMO‐RS model, time to reach 95% of equilibrium for PBDEs between fabric and gas‐phase compounds ranged from 0.1 to >10 years for low to high molecular weight HFRs.     

PCB dechlorination enhancement in Anacostia River sediment microcosms

In situ treatment of PCB contaminated sediments via microbial dechlorination is a promising alternative to dredging, which may be reserved for only the most contaminated areas. Reductive dechlorination of low levels of weathered PCB mixtures typical of urban environments may occur at slow rates. Here, we report that biostimulation and bioaugmentation enhanced dechlorination of low concentration (2.1 mg PCBs/kg dry weight) historical PCBs in microcosms prepared with Anacostia River, Washington, DC, sediment. Treatments included electron donors butyrate, lactate, propionate and acetate (1 mM each); alternate halogenated electron acceptors (haloprimers) tetrachlorobenzene (TeCB, 25 μM), pentachloronitrobenzene (PCNB, 25 μM), or 2,3,4,5,6-PCB (PCB116, 2.0 μM); and/or bioaugmentation with a culture containing Dehalococcoides ethenogenes strain 195 (3 × 10⁶ cells/mL). Dechlorination rates were enhanced in microcosms receiving bioaugmentation, PCNB and PCNB plus bioaugmentation, compared to other treatments. Microcosm subcultures generated after 415 days and spiked with PCB116 showed sustained capacity for dechlorination of PCB116 in PCNB, PCNB plus bioaugmentation, and TeCB treatments, relative to other treatments. Analysis of Chloroflexi 16S rRNA genes showed that TeCB and PCNB increased native Dehalococcoides spp. from the Pinellas subgroup; however this increase was correlated to enhanced dechlorination of low concentration weathered PCBs only in PCNB-amended microcosms. D. ethenogenes strain 195 was detected only in bioaugmented microcosms and decreased over 281 days. Bioaugmentation with D. ethenogenes strain 195 increased PCB dechlorination rates initially, but enhanced capacity for dechlorination of a model congener, PCB116, after 415 days occurred only in microcosms with enhanced native Dehalococcoides spp.     

Polychlorinated biphenyls in indoor dust from urban dwellings of Lahore,Pakistan: Congener profile,toxicity equivalency,and human health implications

This study is the pioneer assessment of the PCBs in indoor dust particles (from air conditioners) of an urbanized megacity from South Asian. The ∑₃₅ PCB concentration ranged from 0.27 to 152.9 ng/g (mean: 24.84 ± 22.10 ng/g). The tri- and tetra-PCBs were dominant homologues, contributing 57.36% of the total PCB concentrations. The mean levels of Σ₈-dioxin-like (DL), Σ₆-indicator PCBs and WHO₂₀₀₅-TEQ for DL-PCBs were 2.22 ± 2.55 ng/g, 9.49 ± 8.04 ng/g and 4.77 ± 4.89 pg/g, respectively. The multiple linear regression indicated a significant correlation of dusting frequency (p = 1.06 × 10–04) and age of the house (p = 1.02 × 10–06) with PCB concentrations in indoor environment. The spatial variation of PCB profile revealed relatively higher concentrations from sites near to illegal waste burning spots, electrical locomotive workshops, and grid stations. Human health risk assessment of PCBs for adults and toddlers through all three exposure routes (ie, inhalation, ingestion, and dermal contact) demonstrated that toddlers were vulnerable to high cancer risk (4.32 × 10⁻⁰⁴), while adults were susceptible from low to moderate levels of risk (3.16 × 10⁻⁰⁵). Therefore, comprehensive investigations for PCBs in the indoor settings, focusing particularly on the sensitive populations with relationship to the electronic devices, transformers, and illegal waste burning sites, are recommended.     

Emission rates and the personal cloud effect associated with particle release from the perihuman environment

Inhalation exposure to elevated particulate matter levels is correlated with deleterious health and well‐being outcomes. Despite growing evidence that identifies humans as sources of coarse airborne particles, the extent to which personal exposures are influenced by particle releases near occupants is unknown. In a controlled chamber, we monitored airborne total particle levels with high temporal and particle‐size resolution for a range of simulated occupant activities. We also sampled directly from the subject's breathing zone to characterize exposures. A material‐balance model showed that a sitting occupant released 8 million particles/h in the diameter range 1‐10 μm. Elevated emissions were associated with increased intensity of upper body movements and with walking. Emissions were correlated with exposure, but not linearly. The personal PM₁₀ exposure increment above the room‐average levels was 1.6‐13 μg/m³ during sitting, owing to spatial heterogeneity of particulate matter concentrations, a feature that was absent during walking. The personal cloud was more discernible among larger particles, as would be expected for shedding from skin and clothing. Manipulating papers and clothing fabric was a strong source of airborne particles. An increase in personal exposure was observed owing to particle mass exchange associated with a second room occupant.     

Seasonality of diffusive exchange of polychlorinated biphenyls and hexachlorobenzene across the air-sea interface of Kaohsiung Harbor, Taiwan

Gaseous and dissolved concentrations of polychlorinated biphenyls (PCBs) and hexachlorobenzene (HCB) were measured in the ambient air and water of Kaohsiung Harbor lagoon, Taiwan, from December 2003 to January 2005. During the rainy season (April to September), gaseous PCB and HCB concentrations were low due to both scavenging by precipitation and dilution by prevailing southwesterly winds blown from the atmosphere of the South China Sea. In contrast, trace precipitation and prevailing northeasterly winds during the dry season (October to March) resulted in higher gaseous PCB and HCB concentrations. Instantaneous air-water exchange fluxes of PCB homologues and HCB were calculated from 22 pairs of air and water samples from Kaohsiung Harbor lagoon. All net fluxes of PCB homologues and HCB in this study are from water to air (net volatilization). The highest net volatile flux observed was + 172 ng m^− 2 day^− 1 (dichlorobiphenyls) in December, 2003 due to the high wind speed and high dissolved concentration. The PCB homologues and HCB fluxes were significantly governed by dissolved concentrations in Kaohsiung Harbor lagoon. For low molecular weight PCBs (LMW PCBs), their fluxes were also significantly correlated with wind speed. The net PCB and HCB fluxes suggest that the annual sums of 69 PCBs and HCB measured in this study were mainly volatile (57.4 × 10³ and 28.3 × 10³ ng m^− 2 yr^− 1, respectively) and estimated yearly, 1.5 kg and 0.76 kg of PCBs and HCB were emitted from the harbor lagoon surface waters to the ambient atmosphere. The average tPCB flux in this study was about one-tenth of tPCB fluxes seen in New York Harbor and in the Delaware River, which are reported to be greatly impacted by PCBs.     

Effects of local point source polychlorinated biphenyl (PCB) contamination on bone mineral density in deer mice (Peromyscus maniculatus)

A former local source of PCBs has contaminated soil and the terrestrial food web at Saglek, Labrador. The relationship between PCB exposure and bone mineral density as an osteoporosis biomarker in deer mice (Peromyscus maniculatus) was investigated at two sites at Saglek: a contaminated Beach and a reference area. Bone mineral density was measured on the femur of twenty-six deer mice using dual-energy X-ray absorptiometry (DXA) technology. Bone mineral density was significantly lower in deer mice from the high exposure site (average whole body ∑PCB = 5769 ng/g wet weight, n = 20) than at the reference site (average whole body ∑PCB = 79.8 ng/g wet weight, n = 7). We used T-scores from the World Health Organization to determine the degree of decreased bone mineral density in exposed mice. Assuming the same biomechanical forces apply as for humans, and using a conservative factor of 1.5 (fracture risk increases 1.5 to 3 fold for every standard deviation decrease in bone mineral density), mice from the contaminated Beach are up to five folds more susceptible to fracture risk than mice from the reference area. Therefore, the PCB concentrations found locally at contaminated military sites such as Saglek are high enough to affect local wildlife.     

Polybrominated diphenyl ethers and polychlorinated biphenyls in indoor dust in Durban,South Africa

Polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) were measured in indoor dust of three microenvironments in Durban, South Africa. The sum of eight PBDEs and three PCBs were quantified by gas chromatography with mass spectral detection. The mean concentrations of ∑_n = 8 PBDEs and ∑_n = 3 PCBs in 10 homes, 11 offices, and 13 university students’ computer laboratories were 1710, 1520, and 818 ng/g, and 891, 923, and 1880 ng/g for PBDEs and PCBs, respectively. The concentration of PCBs found in homes was independent (P = 0.0625) of building construction year. Similarly, no relationship was observed between PCB concentrations and floor type. The concentrations of PBDEs correlated (r = 0.60) with PCB concentrations in homes, thus assuming similar sources. The elevated concentrations of PBDEs and PCBs may have significant implications for human exposure.     

The use of muscle burden in rabbitfish Siganus oramin for monitoring polycyclic aromatic hydrocarbons and polychlorinated biphenyls in Victoria Harbour, Hong Kong and potential human health risk

Muscle concentrations of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) were determined in rabbitfish Siganus oramin collected from Victoria Harbour and its vicinity, Hong Kong from 2004 to 2007. Spatially, relatively higher levels of ∑PAH (1.05-4.26 μg g^− 1) and ∑PCB (45.1-76.9 ng g^− 1) were determined in the central and western sites inside the harbour. Temporally, upward trend of ∑PAH, accompanied with a proportion shift from high molecular weight to low molecular weight PAHs, was detected during the three-year study period, suggesting a heavier marine traffic in Victoria Harbour and its western region. However, human health risk assessment based on five individual PAHs indicated that PAHs in fish muscles posed minimal health risk through consumption. In contrast, a downward trend of ∑PCB was registered as the open use of PCBs has been banned. Despite this, the level of ∑PCB in fish muscles still posed a health risk on the local people who have a high fish consumption rate. While seasonal influences on ∑PAH/∑PCB accumulation in S. oramin seemed to be negligible, our findings in S. oramin were in line with the established PAH and PCB levels in sediments and/or mussels from the harbour, suggesting S. oramin can be used as a model fish species for monitoring PAHs and PCBs in the region.     

Measurements of dermal uptake of nicotine directly from air and clothing

In this preliminary study, we have investigated whether dermal uptake of nicotine directly from air or indirectly from clothing can be a meaningful exposure pathway. Two participants wearing only shorts and a third participant wearing clean cotton clothes were exposed to environmental tobacco smoke (ETS), generated by mechanically “smoking” cigarettes, for three hours in a chamber while breathing clean air from head‐enveloping hoods. The average nicotine concentration (420 μg/m³) was comparable to the highest levels reported for smoking sections of pubs. Urine samples were collected immediately before exposure and 60 hour post‐exposure for bare‐skinned participants. For the clothed participant, post‐exposure urine samples were collected for 24 hour. This participant then entered the chamber for another three‐hour exposure wearing a hood and clothes, including a shirt that had been exposed for five days to elevated nicotine levels. The urine samples were analyzed for nicotine and two metabolites—cotinine and 3OH‐cotinine. Peak urinary cotinine and 3OH‐cotinine concentrations for the bare‐skinned participants were comparable to levels measured among non‐smokers in hospitality environments before smoking bans. The amount of dermally absorbed nicotine for each bare‐skinned participant was conservatively estimated at 570 μg, but may have been larger. For the participant wearing clean clothes, uptake was ~20 μg, and while wearing a shirt previously exposed to nicotine, uptake was ~80 μg. This study demonstrates meaningful dermal uptake of nicotine directly from air or from nicotine‐exposed clothes. The findings are especially relevant for children in homes with smoking or vaping.     

Dermal uptake of phthalates from clothing: Comparison of model to human participant results

In this research, we extend a model of transdermal uptake of phthalates to include a layer of clothing. When compared with experimental results, this model better estimates dermal uptake of diethylphthalate and di‐n‐butylphthalate (DnBP) than a previous model. The model predictions are consistent with the observation that previously exposed clothing can increase dermal uptake over that observed in bare‐skin participants for the same exposure air concentrations. The model predicts that dermal uptake from clothing of DnBP is a substantial fraction of total uptake from all sources of exposure. For compounds that have high dermal permeability coefficients, dermal uptake is increased for (i) thinner clothing, (ii) a narrower gap between clothing and skin, and (iii) longer time intervals between laundering and wearing. Enhanced dermal uptake is most pronounced for compounds with clothing–air partition coefficients between 10⁴ and 10⁷. In the absence of direct measurements of cotton cloth–air partition coefficients, dermal exposure may be predicted using equilibrium data for compounds in equilibrium with cellulose and water, in combination with computational methods of predicting partition coefficients.     

PCDD/Fs and dioxin-like PCBs in home-produced eggs from Belgium: Levels, contamination sources and health risks

This paper discusses the dioxin TEQ levels as determined by the chemically activated luciferase gene expression assay (CALUX) and by HRGC-HRMS in eggs, soils, faeces and kitchen waste samples obtained in the CONTEGG study. The samples were collected in each Belgian province at private homes and in small gardens where chickens are held. The CALUX levels for eggs sampled in autumn were higher than the levels in eggs obtained at the same locations in spring (median values of 5.86 and 4.08 pg CALUX TEQ/g fat, respectively). The total WHO-TEQ levels in eggs, determined by HRGC-HRMS, ranged from 3.29 to 95.35 pg TEQ/g fat in autumn and from 1.50 to 64.79 pg TEQ/g fat in spring. In the soils on which the chickens forage, levels of 2.51-11.35 pg I-TEQ/g in autumn and 2.00-7.86 pg I-TEQ/g in spring were found. The congener pattern of PCDD/Fs in the eggs, soils and faeces was dominated by OCDD, in addition to 1,2,3,4,6,7,8-HeptaCDD, OCDF and 1,2,3,4,6,7,8-HeptaCDF. The predominant dioxin-like PCBs were PCB118, PCB 105 and PCB 156. The dioxin-like PCBs contributed on average 47%, 14% and 20% to the total WHO-TEQ in eggs, soils and faeces, respectively. Kitchen waste samples were very low-contaminated with dioxin-like compounds. The present results showed a good agreement between egg and soil TEQ levels for PCDD/Fs but not for dioxin-like PCBs. This study showed that current soil levels found in some private gardens do not lead to egg levels below the current EU maximal level of 6 pg total TEQ/g fat for dioxins and dioxin-like PCBs. The consumers of the analysed eggs attained 5-79% of the tolerable weekly intake (TWI) of 14 pg TEQ/kg bw for dioxins and dioxin-like PCBs by exposure to their home-produced eggs only.     

Burdens of PBBs, PBDEs, and PCBs in tissues of the cancer patients in the e-waste disassembly sites in Zhejiang, China

This study was conducted to explore the burdens of PBBs, PBDEs, and PCBs among cancer patients living in the e-waste disassembly sites. The contents of 23 PBB congeners, 12 PBDE congeners, and 27 PCB congeners in kidney, liver, and lung samples were measured by GC-MS. The results showed that low-brominated PBBs and PBB153 were the predominant congeners. PBDE47 were the most predominant PBDE congeners. PBDE209 were detected in > 70% of the samples, with geometric means ranging from 64.2 to 113.9 ng g^− 1 lipid. Among the three subfamilies of PHAHs, PCB concentrations were the highest. The detected levels of PHAHs were in the same order of magnitude in the three tissues, which indicated that any of the three tissues could be the suitable indicator for assessing body burdens of PHAHs. PBB contents (181-192 ng g^− 1 lipid) were obviously higher than those reported in the general USA population (3-8 ng g^− 1 lipid). PBDE levels (174.1-182.3 ng g^− 1 lipid) were comparable to those reported in the USA population, but significantly higher than those of the European population. PCBs levels were comparable to those of the European population. The high cancer incidence in the disassembly sites may be related to higher burdens of PBBs, PBDEs, and PCBs in tissues.     

Seasonal variability in environmental tobacco smoke exposure in public housing developments

The risk of tobacco smoking and second‐hand smoke (SHS) exposure combined are the leading contributors to disease burden in high‐income countries. Recent studies and policies are focusing on reducing exposure to SHS in multiunit housing (MUH), especially public housing. We examined seasonal patterns of SHS levels within indoor common areas located on Boston Housing Authority (BHA) properties. We measured weekly integrated and continuous fine particulate matter (PM_2.5) and passive airborne nicotine in six buildings of varying building and occupant characteristics in summer 2012 and winter 2013. The average weekly indoor PM_2.5 concentration across all six developments was 9.2 μg/m³, higher during winter monitoring period (10.3 μg/m³) compared with summer (8.0 μg/m³). Airborne nicotine concentrations ranged from no detection to about 5000 ng/m³ (mean 311 ng/m³). Nicotine levels were significantly higher in the winter compared with summer (620 vs. 85 ng/m³; 95% CI: 72–998). Smoking‐related exposures within Boston public housing vary by season, building types, and resident smoking policy. Our results represent exposure disparities that may contribute to health disparities in low‐income communities and highlight the potential importance of efforts to mitigate SHS exposures during winter when outdoor–indoor exchange rates are low and smokers may tend to stay indoors. Our findings support the use of smoke‐free policy as an effective tool to eliminate SHS exposure and protect non‐smokers, especially residents of MUH.     

Accumulation of polychlorinated biphenyls and organochlorine pesticide in pet cats and dogs: Assessment of toxicological status

PCB and DDT concentrations were determined in the adipose tissue of cats and dogs from Southern Italy. In cats p,p′-DDE was the most abundant DDT component (95.0%), while in dogs these compounds were absent, except in two specimens. PCB concentrations were higher in cats (199.02 ng g^− 1 lipid weight) than in dogs (41.61 ng g^− 1 lipid weight). Also there were inter-specific differences in the contribution of the different congeners to PCBs, although PCB 138, PCB 153 and PCB 180 were the most representative congeners in both species. Animals from one location, Taranto City, had significantly elevated concentrations of dioxin-like PCBs compared to the other locations. Consequently the estimated mean 2,3,7,8-tetrachlorodibenzo-p-dioxin toxic equivalents (TEQs) of coplanar PCBs were higher in these animals (cats: 0.65 pg g^− 1 lipid weight; dogs 0.29 pg g^− 1 lipid weight) than in the other ones (cats: 0.12 pg g^− 1 lipid weight; dogs: 0.001 pg g^− 1 lipid weight).     

Potential for phytoextraction of PCBs from contaminated soils using weeds

A comprehensive investigation of the potential of twenty-seven different species of weeds to phytoextract polychlorinated biphenyls (PCBs) from contaminated soil was conducted at two field sites (Etobicoke and Lindsay) in southern Ontario, Canada. Soil concentrations were 31 μg/g and 4.7 μg/g at each site respectively. All species accumulated PCBs in their root and shoot tissues. Mean shoot concentrations at the two sites ranged from 0.42 μg/g for Chenopodium album to 35 μg/g for Vicia cracca (dry weight). Bioaccumulation factors (BAF = [PCB]_{plant tissue}/[PCB]_{mean soil}) at the two sites ranged from 0.08 for Cirsium vulgare to 1.1 for V. cracca. Maximum shoot extractions were 420 µg for Solidago canadensis at the Etobicoke site, and 120 µg for Chrysanthemum leucanthemum at the Lindsay site. When plant density was taken into account with a theoretical density value, seventeen species appeared to be able to extract a similar or greater quantity of PCBs into the shoot tissue than pumpkins (Curcurbita pepo ssp. pepo) which are known PCB accumulators. Therefore, some of these weed species are promising candidates for future phytoremediation studies.     

Sedimentation of polychlorinated biphenyls (PCBs) in limnic and marine environments

The sedimentation rates of PCBs in two southern Swedish lakes and a coastal bay in the southern Baltic were determined using sediment traps. The rates were similar at the three locations and ranged from 1.2 to 10.9 μg PCBs m⁻² month⁻¹ during summer. The source for PCBs in sedimenting material is probably the atmosphere. PCB concentrations in sedimenting material were higher than those in surface sediment. This may be due to recirculation of sediment-bound PCBs.The reproducibility of collecting by sediment traps was examined by deploying duplicate traps simultaneously. There were no significant differences in PCB concentration of sedimenting material between traps placed in duplicate. Concentrations of PCBs in the different collecting vessel was similar within one trap.     

Potentially harmful secondary metabolites produced by indoor Chaetomium species on artificially and naturally contaminated building materials

The presence of the fungal genus Chaetomium and its secondary metabolites in indoor environments is suspected to have a negative impact on human health and well‐being. About 200 metabolites have been currently described from Chaetomium spp., but only the bioactive compound group, chaetoglobosins, have been screened for and thus detected in buildings. In this study, we used a liquid chromatography high‐resolution mass spectrometry approach to screen both artificially and naturally infected building materials for all the Chaetomium metabolites described in the literature. Pure agar cultures were also investigated to establish differences between metabolite production in vitro and on building materials as well as in comparison with non‐indoor reference strains. On building materials, six different chaetoglobosins were detected in total concentrations of up to 950 mg/m² from Chaetomium globosum along with three different chaetoviridins/chaetomugilins in concentrations up to 200 mg/m². Indoor Chaetomium spp. preferred wood‐based materials over gypsum, both in terms of growth rate and metabolite production. Cochliodones were detected for the first time on all building materials infected by both C. globosum and Chaetomium elatum and are thus candidates as Chaetomium biomarkers. No sterigmatocystin was produced by Chaetomium spp. from indoor environment.     

Variation in residential radon levels in new Danish homes

Radon‐222 gas arises from the radioactive decay of radium‐226 and has a half‐life of 3.8 days. This gas percolates up through soil into buildings, and if it is not evacuated, there can be much higher exposure levels indoors than outdoors, which is where human exposure occurs. Radon exposure is classified as a human carcinogen, and new Danish homes must be constructed to ensure indoor radon levels below 100 Bq/m³. Our purpose was to assess how well 200 newly constructed single detached homes perform according to building regulations pertaining to radon and identify the association between indoor radon in these homes and municipality, home age, floor area, floor level, basement, and outer wall and roof construction. Median (5–95 percentile) indoor radon levels were 36.8 (9.0–118) Bq/m³, but indoor radon exceeded 100 Bq/m³ in 14 of these new homes. The investigated variables explained nine percent of the variation in indoor radon levels, and although associations were positive, none of these were statistically significant. In this study, radon levels were generally low, but we found that 14 (7%) of the 200 new homes had indoor radon levels over 100 Bq/m³. More work is needed to determine the determinants of indoor radon.