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Assessment of nonoccupational exposure to DDT in the tropics and the north: relevance of uptake via inhalation from indoor residual spraying.

Ritter R, Scheringer M, MacLeod M, Hungerbühler K - Environ. Health Perspect. (2011)

Bottom Line: Inuits and the general population in the tropics have similar concentrations.Inhalation exposure explains most of the difference in concentration between the highly exposed and the general population in the Tropics.Continued monitoring of time trends and DDE to DDT ratios in the Tropics and in the North is needed to identify a possible slowdown in concentration decline and the influence of ongoing DDT use.

View Article: PubMed Central - PubMed

Affiliation: Safety and Environmental Technology Group, ETH Zurich, Zurich, Switzerland.

ABSTRACT

Background: People who live in dwellings treated with indoor residual spraying (IRS) of DDT [1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane] for disease-vector control in the tropics and indigenous populations in the Arctic who consume marine mammals experience high nonoccupational exposure to DDT. Although the use of DDT in IRS is rising, the resulting nonoccupational exposure is poorly characterized.

Objectives: We have provided a comparative assessment of exposure to DDT and its metabolites in the general population of the tropical and northern regions and in highly exposed populations in these regions.

Methods: We compiled > 600 average or median DDT concentrations from the peer-reviewed literature, representing > 23,000 individual measurements in humans, food, air, soil, and dust. We use Monte Carlo sampling of distributions based on these data to estimate distributions of population- and route-specific uptake. We evaluate our exposure estimates by comparing them with biomonitoring data.

Results: DDT concentrations are highest in people living in IRS-treated houses and lowest in the northern general population, differing by a factor of about 60. Inuits and the general population in the tropics have similar concentrations. Inhalation exposure explains most of the difference in concentration between the highly exposed and the general population in the Tropics. Calculated exposure levels are consistent with human biomonitoring data.

Conclusions: Nonoccupational inhalation exposure is a relevant exposure pathway for people living in homes treated by IRS of DDT. Continued monitoring of time trends and DDE to DDT ratios in the Tropics and in the North is needed to identify a possible slowdown in concentration decline and the influence of ongoing DDT use.

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Related in: MedlinePlus

Results of the integrated exposure assessment representing the period of 1995–2008. Boxes represent median (central line) and 25th and 75th percentiles; whiskers mark 5th and 95th percentiles. (A) Daily uptake of ∑DDT from different exposure routes. (B) Total daily uptake resulting from combination of route-specific uptakes shown in (A). (C) Measured and modeled concentrations of ∑DDT in humans. Modeled distributions in (C) were calculated from total uptakes shown in (B). Because of efficient uptake of ∑DDT via the dietary and inhalation routes, our results, presented as uptakes, closely reflect intakes. References for empirical data are given in the Supplemental Material, Tables 1 and 7 (doi:10.1289/ehp.1002542).
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f2-ehp-119-707: Results of the integrated exposure assessment representing the period of 1995–2008. Boxes represent median (central line) and 25th and 75th percentiles; whiskers mark 5th and 95th percentiles. (A) Daily uptake of ∑DDT from different exposure routes. (B) Total daily uptake resulting from combination of route-specific uptakes shown in (A). (C) Measured and modeled concentrations of ∑DDT in humans. Modeled distributions in (C) were calculated from total uptakes shown in (B). Because of efficient uptake of ∑DDT via the dietary and inhalation routes, our results, presented as uptakes, closely reflect intakes. References for empirical data are given in the Supplemental Material, Tables 1 and 7 (doi:10.1289/ehp.1002542).

Mentions: Total uptake of ∑DDT is highest in the THEP, about equal in the TGP and NHEP, and lowest in the NGP (Figure 2B, Table 2). The total uptake in the THEP exceeds the total uptake in the TGP by about a factor of 5, and total uptake in the NHEP exceeds uptake in the NGP by a factor of 12.


Assessment of nonoccupational exposure to DDT in the tropics and the north: relevance of uptake via inhalation from indoor residual spraying.

Ritter R, Scheringer M, MacLeod M, Hungerbühler K - Environ. Health Perspect. (2011)

Results of the integrated exposure assessment representing the period of 1995–2008. Boxes represent median (central line) and 25th and 75th percentiles; whiskers mark 5th and 95th percentiles. (A) Daily uptake of ∑DDT from different exposure routes. (B) Total daily uptake resulting from combination of route-specific uptakes shown in (A). (C) Measured and modeled concentrations of ∑DDT in humans. Modeled distributions in (C) were calculated from total uptakes shown in (B). Because of efficient uptake of ∑DDT via the dietary and inhalation routes, our results, presented as uptakes, closely reflect intakes. References for empirical data are given in the Supplemental Material, Tables 1 and 7 (doi:10.1289/ehp.1002542).
© Copyright Policy - public-domain
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3094425&req=5

f2-ehp-119-707: Results of the integrated exposure assessment representing the period of 1995–2008. Boxes represent median (central line) and 25th and 75th percentiles; whiskers mark 5th and 95th percentiles. (A) Daily uptake of ∑DDT from different exposure routes. (B) Total daily uptake resulting from combination of route-specific uptakes shown in (A). (C) Measured and modeled concentrations of ∑DDT in humans. Modeled distributions in (C) were calculated from total uptakes shown in (B). Because of efficient uptake of ∑DDT via the dietary and inhalation routes, our results, presented as uptakes, closely reflect intakes. References for empirical data are given in the Supplemental Material, Tables 1 and 7 (doi:10.1289/ehp.1002542).
Mentions: Total uptake of ∑DDT is highest in the THEP, about equal in the TGP and NHEP, and lowest in the NGP (Figure 2B, Table 2). The total uptake in the THEP exceeds the total uptake in the TGP by about a factor of 5, and total uptake in the NHEP exceeds uptake in the NGP by a factor of 12.

Bottom Line: Inuits and the general population in the tropics have similar concentrations.Inhalation exposure explains most of the difference in concentration between the highly exposed and the general population in the Tropics.Continued monitoring of time trends and DDE to DDT ratios in the Tropics and in the North is needed to identify a possible slowdown in concentration decline and the influence of ongoing DDT use.

View Article: PubMed Central - PubMed

Affiliation: Safety and Environmental Technology Group, ETH Zurich, Zurich, Switzerland.

ABSTRACT

Background: People who live in dwellings treated with indoor residual spraying (IRS) of DDT [1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane] for disease-vector control in the tropics and indigenous populations in the Arctic who consume marine mammals experience high nonoccupational exposure to DDT. Although the use of DDT in IRS is rising, the resulting nonoccupational exposure is poorly characterized.

Objectives: We have provided a comparative assessment of exposure to DDT and its metabolites in the general population of the tropical and northern regions and in highly exposed populations in these regions.

Methods: We compiled > 600 average or median DDT concentrations from the peer-reviewed literature, representing > 23,000 individual measurements in humans, food, air, soil, and dust. We use Monte Carlo sampling of distributions based on these data to estimate distributions of population- and route-specific uptake. We evaluate our exposure estimates by comparing them with biomonitoring data.

Results: DDT concentrations are highest in people living in IRS-treated houses and lowest in the northern general population, differing by a factor of about 60. Inuits and the general population in the tropics have similar concentrations. Inhalation exposure explains most of the difference in concentration between the highly exposed and the general population in the Tropics. Calculated exposure levels are consistent with human biomonitoring data.

Conclusions: Nonoccupational inhalation exposure is a relevant exposure pathway for people living in homes treated by IRS of DDT. Continued monitoring of time trends and DDE to DDT ratios in the Tropics and in the North is needed to identify a possible slowdown in concentration decline and the influence of ongoing DDT use.

Show MeSH
Related in: MedlinePlus