PowerPointPrsentation

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Miljøbelastning med anthropogene stoffer
Eksempel bly konsekvenser, iagttagelser og
helbred Hans von StorchInstitut für
Küstenforschung, GKSS Forschungszentrum
Kemisk Institut, København, 13 Dezember 2006
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(No Transcript)
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The case of Germany
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Questions

• Is it doable to estimate lead concentrations in
  the atmosphere and in human blood with a simple
  regression-type model?
• What were the levels of lead concentration in
  human blood in Germany in the 196s and 1970s (a
  time for which no measurements are available)?
• How can we design scenarios of lead levels in
  human blood conditional upon alternative
  political regulations?

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Annual gasoline sales and lead emissions in
Germany. Volume of gasoline sold (millions of
liters per year solid) and of leaded gas (after
1985 red crosses) amount of lead added to
gasoline (in tons yellow).
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We have two data sets with time series of lead
concentrations in human blood (LHB), beginning in
the late 1970s. No reliable earlier data about
lead in the human blood in Germany is available.
Data set G (Germany Heinzow, 1998) is
unsystematically collected, with samples at
different locations, different methods, different
age and gender groups. The second data set M
(Münster Human-Probenbank Münster 2002) is
better, as it is derived from a controlled
sampling strategy for groups of students living
in the industrial town of Münster (51.5oN, 7.4oE)
in Nordrhine-Westfalia, close to the Ruhr area
with heavy industry and intensive road traffic.
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Data set G (Heinzow) and M (Münster) with
lead concentration in human blood (in ?g/l). The
G data are split into adults and children.
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Similarity of lead concentration in human blood
sampled in the same year.Based on G and M data.
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Lead concentration in gasoline and in blood in
Germany. Heinzow (G) and Münster (M) data sets.
The lead concentration in 1985 to 1995 is an
"effective" concentration for West Germany, by
proportionally weighting the concentrations in of
leaded (0.015 g/l) and unleaded (0.013 g/l)
gasoline
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Data set G There is a linear relationship
between the mean concentration and the dispersion
of the sample distributions. standard deviation
0.43? mean 3.9, (1) 95 quantile 1.63 ?
mean 10.9 (2)
Scatter diagrams of sample means (horizontal
axis) and sample standard deviations (dots, red)
and 95 quantiles (diamonds, green) in lead
concentrations in human blood in data set G. In
?g/l.
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Data set G According to (1), if the mean blood
concentration is 150 ?g/l, then on average one
sixth of the population will have more than 200
?g/l or less than 100?g/l. This rough estimate is
based on the assumption of a normal distribution,
which is not really valid as the distribution of
lead levels is skewed, with a long tail towards
large values . Thus, it is more appropriate
to use percentiles If the mean concentration is
150?g/l, then according to (2) 5 of the
population may have a concentration of more
than 250 ?g/l.
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Critical Values of Lead Concentration in Human
Blood
Defined by the Human-Biomonitoring-Kommission
in Germany
women in child-bearing age
Category 1 unobstrusive value Category 2 no
health risks are expected but monitoring is
recommended Category 3 health hazards are
possible, clarification and mitigation is needed
Source Krause et al. 1996
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Scatter diagrams of sample means (horizontal
axis) and sample 95 (diamonds) and 90 (dots)
quantiles (vertical axis) in lead concentrations
in human blood in data set M. In ?g/l.
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In case of data set M, the 90 and 95 quantiles
are given. Also in this case, a clear linear
relationship between the mean and the quantiles
is emerging with 90 quantile 1.46 ? mean
2.2 (3) 95 quantile 1.75 ? mean 4.6.
(4) According to (3) and (4), a mean
concentration of 150?g/l is associated with 5
(10) of the population having more than 258 ?g/l
(217 ?g/l) lead in their blood.
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A simple dynamical relationship between three
variables, namely the emission of lead LEt in an
area AE in the year t, the atmospheric
concentration LCt in an area AC in the year t and
the mean concentration of lead in human blood
LHBt in the year t in the area AC. LCt1 ?
LCt ? LEt1 (5) LHBt1 ? LHBt ?
LCt1 ? (6) Equation (6) is equivalent
to (LHBt1 - ?) ? (LHBt - ?) ? LCt1
(7) with ? ?/(1-?). Formulation (7) describes
the dynamics of anomalies LHBt-? relative to a
normal state ? towards which the system
converges as soon as the forcing LCt ceases if
???lt1. For 0 lt ? lt1 the air concentration
approaches ? asymptotically with a time scale of
1/(1-?) if LCt0.
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Estimates of emitted lead in Germany in
tons/year. Dots Linearly interpolated estimates
by Pacyna and Pacyna (2000). Crosses Estimates
based on volume of gasoline sold in West Germany,
according to MWV (1998, 2002)
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Best guess of lead emissions in the 6-grid box AE
surrounding Münster in tons/year. The times with
an estimate from Pacyna is given by a big dot.
The blue time series is used as input in the
reconstruction 1955-1995 of lead concentrations
in the air (5) and in the blood (7).
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Equation 5/6
LCt1 a LCt ß LEt1
LHBt1 ? LBHt d LCt1 e
LC lead concentration in the atmosphere LE
total lead emission LHB lead concentration in
human blood
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Lead concentration LCt in the air, in ng/m3, in
the 50 ? 50 km2 grid cell containing the town of
Münster as simulated in the reconstruction, and
as estimated using the linear model (5) (red)
Münster emissions LEt.
LCt1 ? LCt ? LEt1 (5)
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(LHBt1 - ?) ? (LHBt - ?) ? LCt1 (7) 95
quantile 1.75 ? mean 4.6. (4)
Fit of equation (7) and test of equation (4) for
data set M.. The upper two curves refer to the
95-iles, and the lower two to the means. The
estimated mean curve is derived by using
simulated air concentrations in Münster and the
1981 observed blood level as initial value the
curve for the estimated 95-iles is obtained by
using the estimated means and applying formula
(4).
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Estimated mean, 90ile and 95ile lead
concentrations in human blood in Münster,
according to (6/7) and (3/4 (red solid lines, M).
Additionally the mean level estimated with the
Germany model is given as dotted blue curve (G).
A level of more than 150 ?g/l are considered in
Germany as potentially harmful for children and
women in child-bearing age (HBM 3). For other
adults the limit for serious concern is set to
250 ?g/l.
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Three scenarios of reduction of lead used as
anti-knock in gasoline in Germany. The big black
symbols describe the actual concentrations.
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Scenarios for mean lead concentrations (?g/l)
in human blood, as derived by the Münster model.
Scenario 1 describes an evolution without
regulation (i.e., ongoing use of 0.6 g/l lead in
gasoline in Germany, upper curves). In scenario 2
no unleaded gasoline has been introduced in
Germany in 1985 (middle curves), and in scenario
3, regulation was instituted in Germany already
in 1961 (lower curves).
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Conclusions

• It is possible to reconstruct atmospheric lead
  concentrations and blood lead levels using a
  simple regression model
• It is possible to estimate lead concentrations in
  human blood using only lead emissions
• Reducing the lead content in gasoline was a
  successful environmental policy to limit human
  health risks

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Rest of the world
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USA
After Kitman, Nation 270, March 20, 2000
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May 8, 2001 New Warnings on Lead and Children By
ERIC NAGOURNEY new study raises questions about
whether the current measure used to define lead
poisoning is stringent enough. Lead poisoning has
been redefined over the years, as doctors have
decided that smaller and smaller amounts are
acceptable. It is now considered to occur at 10
micrograms of lead per deciliter of blood. But
researchers told a recent gathering of the
Pediatric Academic Societies of evidence that
even at levels lower than that, lead in the
bloodstream appears dangerous. The primary
researcher, Dr. Bruce Lanphear of the Children's
Hospital Medical Center of Cincinnati, said that
in the children he and his colleagues had
studied, I.Q. declined in those with less than 10
micrograms of lead per deciliter of blood. The
findings, he said, suggest that millions more
children in the United States than previously
suspected may be at risk. "This is clearly a
major public health crisis, and there really is
too much complacency about this as a public
health issue," he said. The researchers studied
276 children born in five hospitals in Rochester,
N.Y., and then kept track of them for five years,
measuring their lead levels and then their I.Q.'s
at age 5. The researchers reported finding an
inverse relationship between I.Q. and lead
levels. Among all the children, they said, there
was an average 5.5 percent reduction in I.Q. for
every 10-microgram increase in lead.
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Lead Use in Gasoline in 1996
Source modified from World Bank 1997
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Thomas and Kwong, 2001
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Blood Lead Levels in Different Cities in 1980s
and 1990s
blood lead level (mg/l)
years of sampling
US- scientists expect health dangers for children
above a blood lead level of 100mg/l.
German experts are convinced there can be health
dangers above 150mgPb/l.
Source World Bank (1997), Heinzow et al. (1998)
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Web-page http//w3g.gkss.de/staff/blei/index.htm
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