Daily intake
(EDI) of plasticizers via dust ingestion or dermal contact was determined
using the following equations29 (link),45 (link) where EDI is the estimated daily intake (ng/kg body weight/day), C is the concentration of a chemical in house dust (ng/g),
IEF is the indoor exposure fraction (hours spent over a day in homes),
DIR is the dust ingestion rate (g/day), BW is body weight (kg), BSA
is body surface area (cm2/day), SAS is the amount of solid
particles adhered onto skin (mg/cm2), and FA is the fraction
of a chemical absorbed through the skin. We assumed a 100% absorption
of chemicals from ingested dust. Due to the lack of experimental and
model data of skin absorption of NPPs, the skin absorption fraction
of NPPs was assumed to be 0.000031 (low exposure) or 0.01025 (high
exposure) according to the experimental data of PAEs (0.000031–0.01025).46 (link) Other parameters included in the equations are
summarized inTable S3 .
The hazard
quotient (HQ) was determined to assess human exposure risks via dust
ingestion and dermal absorption. Only chemicals with a DF of >70%
in at least four of the five regions were included for HQ estimation47 where RfD
represents the reference dose of a target chemical. For an analyte
without an appropriate RfD, its nonobserved-adverse-effect-level
(NOAEL) or lethal dose (LD50) adjusted with an uncertainty
factor was applied (Table S4 ). A hazard
index (HI) was also calculated by summing the HQs for individual analytes.
For a target analyte with a detection frequency (DF) > 70%,
an
LOQ/√2 was assigned to any measurements below the LOQ for statistical
analysis. Statistical analyses and data visualization were conducted
using Origin version 9.0 or PASW Statistics 18.0. Differences among
chemical groups or regions were determined using a Kruskal–Wallis
analyses of variance (ANOVA) followed by a Mann–Whitney test.
Spearman’s correlation analyses were used to determine the
relationships between individual plasticizers in house dust. The level
of significance was set at α = 0.05.
(EDI) of plasticizers via dust ingestion or dermal contact was determined
using the following equations29 (link),45 (link) where EDI is the estimated daily intake (ng/kg body weight/day), C is the concentration of a chemical in house dust (ng/g),
IEF is the indoor exposure fraction (hours spent over a day in homes),
DIR is the dust ingestion rate (g/day), BW is body weight (kg), BSA
is body surface area (cm2/day), SAS is the amount of solid
particles adhered onto skin (mg/cm2), and FA is the fraction
of a chemical absorbed through the skin. We assumed a 100% absorption
of chemicals from ingested dust. Due to the lack of experimental and
model data of skin absorption of NPPs, the skin absorption fraction
of NPPs was assumed to be 0.000031 (low exposure) or 0.01025 (high
exposure) according to the experimental data of PAEs (0.000031–0.01025).46 (link) Other parameters included in the equations are
summarized in
The hazard
quotient (HQ) was determined to assess human exposure risks via dust
ingestion and dermal absorption. Only chemicals with a DF of >70%
in at least four of the five regions were included for HQ estimation47 where RfD
represents the reference dose of a target chemical. For an analyte
without an appropriate RfD, its nonobserved-adverse-effect-level
(NOAEL) or lethal dose (LD50) adjusted with an uncertainty
factor was applied (
index (HI) was also calculated by summing the HQs for individual analytes.
For a target analyte with a detection frequency (DF) > 70%,
an
LOQ/√2 was assigned to any measurements below the LOQ for statistical
analysis. Statistical analyses and data visualization were conducted
using Origin version 9.0 or PASW Statistics 18.0. Differences among
chemical groups or regions were determined using a Kruskal–Wallis
analyses of variance (ANOVA) followed by a Mann–Whitney test.
Spearman’s correlation analyses were used to determine the
relationships between individual plasticizers in house dust. The level
of significance was set at α = 0.05.
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