8. BIOLOGICAL MONITORING AND THE RESULTS OF HUMAN EXPOSURE TO TOXIC SUBSTANCES FROM THE ENVIRONMENT
 Summary of basic results in the period 1994–2003

8.1 Organization of monitoring activities

This subsystem comprises the monitoring of toxic substances and their metabolites (biomarkers of internal doses), and selected biological changes (biomarkers of biological effects) in the body fluids and tissue of population groups (adults, children aged 8–10 years, post-puerperal mothers and the deceased) in 4 selected cities: Benešov, Žďár nad Sázavou, Plzeň and Ústí nad Labem, during 1994–2003. Each monitored region comprises 100 subjects from the monitored population group. Basic demographic data and information on lifestyle necessary for estimating population exposure to contaminants have been collected by means of a brief questionnaire. The subsystem is supplemented with monitoring of the mutagenic activity of particulate matter, fraction PM10 in ambient air from the above cities.

Since 2005, biological monitoring has been performed in Ostrava, Prague, Liberec and Zlín.

Participating analytical laboratories were subjected to constant quality control of results produced. Inter-laboratory differences have been minimised by defining analyses according to matrix or analyte, respectively. The laboratories involved have gradually acquired CIA accreditation. The results of the analyses are presented as a graph, showing actual conditions in specific years of monitoring as well as the development of long-term time sequences.

The biological exposure limits of toxic substances in human biological materials have not generally been established for the non-occupationally exposed population. However, for certain hazardous analytes, a so-called maximum tolerable level has been established. Exceeding these values signalises a potential risk to population health. The homogeneity of data and their compatibility with data found in analogous foreign studies along with the continuity of the Monitoring System allows their application for determination of reference values characterising the population burden during a given period. A certain extent of individual variability may be caused by differences in the magnitude of exposure and the individual sensitivity of the human organism to environmental pollution.

8.2 Monitored factors

The factors (biomarkers) monitored over the complete monitoring period include toxic metals (cadmium, mercury, lead) and beneficial trace elements (copper, selenium, zinc) in adult and child blood and urine, and the hair of children. Lead levels were monitored in the teeth of pre-school children. Persisting chlorinated organic substances (indicator congeners of polychlorinated biphenyls – PCBs – and selected chlorinated pesticides) were analysed in breast milk, subcutaneous fat from the deceased, and, in 2002 also the blood sera of adults. Ochratoxin A levels were monitored in adult blood. Cytogenetic analyses of human peripheral lymphocytes in the adults and children were monitored in intervals of 2–3 years. Other analytes were incorporated into the monitoring system in the form of pilot studies. The bacterial mutagenicity of the PM10 fraction of particulate matter in ambient air was likewise monitored.

8.2.1 Toxic metals and trace elements

Cadmium has an exceptionally long biological half-life (15–30 years) and consequent ability to accumulate in the organism. Its dangerous effects include nephrotoxicity and carcinogenicity, and, on interaction with calcium, osteoporosis and osteomalacia. The blood cadmium level is a biomarker of current population exposure and is influenced by the smoking habit. The marked significance of smoking was confirmed in the adult Czech population, where the blood cadmium level was 2–3 times higher than in non-smokers (Figs. 8.1a, 8.1b). A gradual but significant decrease has been observed in the non-smoking population. However, smoking does not have a marked effect on cadmium levels in urine (Tab. 8.1). Higher values have been detected in female urine. In children, the blood and urine concentrations are below the detection limit of the method used in over 50 % of samples.

Neurobehavioral and developmental changes may occur in young children at blood lead values of 100 µg/L or even less; monitoring has not detected such levels. Blood lead levels in the adult Czech population have declined significantly during the monitoring period. This has led to a re-evaluation (decrease) of reference values. Lead levels are higher in men than in women (Figs. 8.2a, 8.2b). Blood lead levels for the Czech population correlate with data for the German population within GerES, and with data from other European states. Blood lead levels in children are lower than adult levels, but do not change significantly in time (Fig. 8.2c). However, the distribution of levels reveals a shift towards lower values: in 2001, 10 % of children had up to 20 µg/L compared to 7 % in 1996, 20–40 µg 70 % compared to 57 %, only 16 % had 40–60 µg in 2001 compared to 28 % in 1996, only 3 % with 60–100 µg compared to 7 % (Fig. 8.2d). Analyses of lead in children’s teeth suggest decreasing population burden by Pb, too (Tab. 8.3).

Of the existing forms of mercury, methyl-mercury has the most serious adverse effects on health due to its neurotoxicity. Mercury levels in blood do not signalise any increased burden in the adult Czech population. Blood and urine mercury levels correlate with data for the German population within GerES, and with other European states (Tab 8.1). In the child population concentrations are roughly halved in comparison to adults (Figs. 8.3a, 8.3b). Higher values are detected in the female population.

Copper is contained in a number of antioxidant enzymes and plays a role in hematopoiesis and lipid metabolism. The effects of copper are determined in relation to zinc and iron content in the organism. Blood copper levels correlate with data for the German population within GerES, and with other European states. A rising trend was observed prior to 1999, after which the concentrations stabilised. Higher concentrations have been detected in mature and juvenile females (Figs. 8.4a, 8.4b). Copper concentrations in urine are shown in Tab 8.1; a rising trend was observed up to 2002.

Selenium is considered to be a trace element with beneficial effects and its antioxidant potential plays a role in protective mechanisms against oxidation stress and resulting disorders promoted by that process (cancer, cardiovascular and endocrine system diseases). The blood, serum or plasma selenium level is an indicator of saturation with this element. Concentration in the range of 90–150 µg/L is considered optimal in blood serum. Blood selenium levels had a significant rising trend among the adult Czech population, although the existing values have not thus far reached optimal saturation (Fig. 8.5a). Blood selenium levels are stable and lower in the child population than in adults (Fig. 8.5b). Selenium levels in urine have a rising tendency in the adult population, although no such trend has been observed in children (Tab. 8.1).

Zinc is likewise an essential element contained in a number of enzymes and plays a role in immune function and antioxidant processes. Blood zinc concentrations in the adult population have stabilised, following an initial increase in 1998 (Fig. 8.6a). In children, blood concentrations have remained unchanged over the years of monitoring (Fig. 8.6b). Mature and juvenile females have lower values than mature and juvenile males. Zinc concentrations in urine are stable (Tab. 8.1).

8.2.2 Toxic substances of organic origin

Systematic monitoring was performed of PCB indicator congeners and selected chlorinated hydrocarbons in breast milk. The results have confirmed the dominance of congeners 138, 153 and 180 which persist in the organism for long periods. Other PCB congener values are over 50 % below the detection limit. Results from the overall monitoring period (1994–2003) indicate a significant increase with age regardless of the chronological order of parturition. The decrease with time recorded in the 1994–2001 period stabilised during 2002–2004. The long-term trend is demonstrated by use of the PCB indicator congener 153 (Fig. 8.7a).

DDT concentrations presented as the sum of DDT and DDE metabolites has a decreasing trend associated with gradual decline in burden, as documented since the end of the 1980s (Fig. 8.7b). Hexachlorobenzene (HCB) concentrations in breast milk have a constant and significant declining trend over the monitoring period (Fig. 8.7c).

Czech population burden from ochratoxin A is at a low level, with median values of 0.1–0.2 µg/L of sera. However, results indicate local differences with significantly higher values in the monitored regions of Benešov and Žďár nad Sázavou, which are more recreational and agricultural regions as opposed to the other, industrial regions.

8.3 Cytogenetic analysis of peripheral lymphocytes

Cytogenetic analysis of peripheral lymphocytes used for biological monitoring of population groups enables the detection of active genotoxic substances in the environment and indication of individual resistance to, and compensation of, genotoxic burden. Values of chromosomal aberrations that are significantly higher than reference values for given monitored population groups may reveal increased exposure to genotoxic substances from the environment.

Existing data shows that values for chromosomal aberrations (CH.A) in adult population groups from four areas in the Czech Republic had a declining trend, as monitored prior to 1999; this is particularly apparent in view of the levels of spontaneous values of 1.77 % in the 1977–1993 period (prior to monitoring) to mean values of approx. 1 %. This declining trend reversed during the last two stages of monitoring in 2001 and 2003, with a return to CH.A values which were common in the 1980s (Tab. 8.4). It is necessary to carefully analyse the causes of this increase, as related to environmental burden and provision of prophylactic substances and balanced diet. It is also unclear if the areas included in the system of biological monitoring during the 1994–2003 period are, as regards cytogenetic analyses, adequately representative for the Czech Republic. The solution to this may be provided by the current monitoring period which started in 2005 in the Prague, Ostrava, Liberec and Zlín regions.

Values of chromosomal aberrations in the child population are generally lower than those for adults; there was a declining tendency for both child and adult populations in the 1994–1996 period, which stabilised in 1999–2001 (Tab. 8.4). Cytogenetic analyses of umbilical blood in the 1994–1995 period revealed mean values of 1.10 %.

8.4 Genotoxic effects of ambient air

Systematic monitoring of the mutagenic activity of airborne particulate matter (PM10) in association with analyses of polycyclic aromatic hydrocarbons in Subsystem I was started at the end of 1996 and since 1997 has been carried out continually at 18-day intervals for 24-hour periods. In view of the significantly higher values demonstrated in winter months, sampling was again limited to two periods: January–March and October–December. The results of mutagenic activity of ambient air have a rising trend in time. The highest mutagenic values detected in samples of Prague air signal deterioration of outdoor air, probably associated with traffic load (Fig. 8.8).

8.5 Partial conclusions

The results of 10 years of biological monitoring reveal a declining trend for the majority of monitored xenobiotics and correlate with data from other European states. In particular, there is a declining trend lead in blood, a confirmed reduction of cadmium and improved saturation by selenium in the adult population. Likewise, there is a declining trend for persistent chlorinated organic substances (PCBs, DDTs, hexachlorobenzene). Burden by these substances is firmly associated with age and variable local or individual exposure in the past. Monitoring of mycotoxins suggests higher exposures in agricultural regions.

The rising trend in values of chromosomal aberrations, including mutagenicity of outdoor air, observed over the past five years indicates increased population burden by genotoxic substances and factors, and requires detailed analysis of the possible causes.

Tab. 8.1 Metal and metaloid levels in urine of adults and children (8–10 years), [µg/g creatinine]

Cadmium

Adults

Children

1996

1998

2000

2002

2003

1996

1997

1998

1999

2000

2002

2003

N

361

367

359

366

363

426

388

357

362

368

349

270

Me

0.62

0.58

0.31

0.40

0.29

DL

DL

DL

DL

DL

DL

DL

P5

0.20

0.25

0.20

0.10

0.10

 

 

 

 

 

 

 

P25

0.24

0.25

0.20

0.18

0.10

 

 

 

 

 

 

 

P75

1.08

1.26

0.71

0.73

0.56

 

 

 

 

 

 

 

P95

3.82

2.91

1.55

1.42

1.34

 

 

 

 

 

 

 


Lead

Adults

Children

1996

1998

2000

2002

2003

1996

1997

1998

1999

2000

2002

2003

N

304

290

330

335

322

426

388

357

362

368

349

270

Me

3.35

2.54

4.42

3.12

2.67

3.76

1.59

1.86

0.27

1.52

3.54

DL

P5

0.72

1.14

1.53

1.02

0.77

0.78

0.16

0.15

0.10

0.13

1.98

 

P25

1.67

1.63

2.38

1.82

1.69

1.43

0.69

0.48

0.16

0.38

2.81

 

P75

6.07

4.23

10.71

6.16

5.95

8.44

3.57

6.39

1.26

3.50

4.57

 

P95

15.46

11.00

35.35

21.09

20.36

17.57

15.13

25.69

8.48

13.01

6.39

 


Mercury

Adults

Children

1996

1998

2000

2002

2003

1996

1997

1998

1999

2000

2002

2003

N

304

290

330

335

322

426

388

357

362

368

349

270

Me

0.79

0.55

0.68

0.53

0.70

0.25

0.38

0.26

0.27

0.35

0.43

0.28

P5

0.08

0.09

0.10

0.05

0.07

0.06

0.04

0.04

0.06

0.07

0.10

0.08

P25

0.40

0.26

0.29

0.14

0.25

0.15

0.18

0.14

0.14

0.16

0.18

0.14

P75

1.55

1.19

1.44

1.72

1.81

0.54

0.85

0.73

0.74

0.83

1.24

0.87

P95

3.87

3.80

5.47

6.45

6.80

2.59

2.49

3.85

2.64

3.15

3.94

4.46


Copper

Adults

Children

1998

2000

2002

2003

1996

1997

1998

1999

2000

2002

2003

N

290

330

335

322

426

388

357

362

368

349

270

Me

6.2

6.0

21.5

14.2

10.0

30.5

35.5

29.9

32.2

41.8

24.1

P5

0.3

2.5

5.7

6.2

1.3

3.9

5.8

13.0

10.7

5.6

5.6

P25

3.5

4.4

13.0

10.1

7.6

17.8

24.6

22.3

22.7

25.2

13.4

P75

16.9

9.0

30.7

20.6

36.4

42.1

50.6

44.2

43.4

58.8

38.7

P95

43.6

18.9

51.9

43.0

150.7

87.5

86.6

74.4

64.8

93.4

74.7


Selenium

Adults

Children

1998

2000

2002

2003

1996

1997

1998

1999

2000

2002

2003

N

290

330

335

322

426

388

357

362

368

349

270

Me

8.20

8.66

15.32

10.99

15.42

12.87

7.15

16.00

18.34

17.68

14.01

P5

2.16

1.51

1.69

1.41

0.93

0.57

2.69

1.44

1.54

4.50

3.67

P25

3.69

4.49

8.58

5.87

1.83

3.47

4.68

5.55

7.30

8.80

10.19

P75

26.09

15.23

22.29

17.74

47.38

29.83

12.38

39.55

37.05

39.87

19.98

P95

50.18

30.85

39.37

32.39

95.00

70.05

44.12

110.38

70.51

126.32

29.20


Zinc

Adults

Children

1998

2000

2002

2003

1996

1997

1998

1999

2000

2002

2003

N

290

330

335

322

426

388

357

362

368

349

270

Me

300

355

375

287

547

323

513

422

402

468

518

P5

71

135

122

54

128

42

58

136

148

112

222

P25

205

242

253

178

370

173

274

278

286

305

376

P75

451

477

532

431

860

524

805

582

535

667

713

P95

707

763

865

698

1,365

874

1,388

922

846

1,013

1,088

Tab. 8.2 Metal and metaloid levels in hair of children (8–10 years), [µg/g]

 

Cadmium

Lead*

Mercury

Copper

Selenium

Zinc

N

343–412

292–412

292–412

292–412

292–412

292–412

Me

0.12–0.20

1.17–2.03

0.14–0.23

9.0–12.0

0.14–0.34

118–134

P5

0.04–0.05

0.49–0.73

0.04–0.09

5.0–8.0

0.10–0.18

49–75

P25

0.07–0.09

0.85–1.32

0.09–0.16

7.0–9.0

0.10–0.26

89–105

P75

0.19–0.34

1.59–2.87

0.20–0.37

12.0–20.0

0.20–0.52

144–171

P95

0.36–0.63

3.19–5.10

0.30–0.84

34.5–73.5

0.37–0.90

179–229

* significantly decreasing trend

Tab. 8.3 Lead levels in deciduous teeth [µg/g]

 

1998

1999

2000

2001

2002

2003

N

179

204

171

142

177

60

Me

0.83

1.31

1.39

0.95

0.74

0.63

P5

0.30

0.55

0.69

0.28

0.32

0.11

P25

0.56

0.85

1.00

0.64

0.56

0.43

P75

1.41

2.04

2.18

1.32

1.24

1.09

P95

2.71

3.37

4.65

2.51

2.37

1.63

Legend for Tables 8.1–8.3:
N – no. of individuals
Me – median
P5 – 5
th percentile
P25 – 25
th percentile
P75 – 75
th percentile
P95 – 95
th percentile
DL – > 50 % of samples under the limit of detection
Limit of detection Cd – 0.3 µg/L
Pb – 7.0 µg/L

Tab. 8.4 Cytogenetic analysis – chromosomal aberrations in blood peripheral lymphocytes of adults and children

Adults

%AB.B.

%AB.B.

%AB.B.

%AB.B.

%AB.B.

1994

1996

1999

2001

2003

N

626

330

366

392

382

AVG

1.40

1.04

1.06

1.26

1.65

P25

0.00

0.00

0.00

0.00

1.00

P75

2.00

2.00

2.00

2.00

2.00

P95

4.00

3.00

3.00

3.00

4.00


Children
8–10 years of age

%AB.B.

%AB.B.

%AB.B.

%AB.B.

%AB.B.

1994

1995

1996

1999

2001

N

351

459

350

338

351

AVG

1.29

1.23

0.92

1.14

1.10

P25

0.00

0.00

0.00

0.00

0.00

P75

2.00

2.00

1.00

2.00

2.00

P95

4.00

4.00

3.00

3.00

3.00

Legend:
%AB.B. – share of aberrant cells
N – no. of individuals
AVG – arithmetic mean
P25 – 25
th percentile
P75 – 75
th percentile
P95 – 95
th percentile

Fig. 8.1a Blood cadmium level in adults – smokers
Fig. 8.1b Blood cadmium level in adults – non-smokers
Fig. 8.2a Blood lead level in adults – males
Fig. 8.2b Blood lead level in adults – females
Fig. 8.2c Blood lead level in children
Fig. 8.2d Distribution of blood lead levels in children, 1996 and 2001
Fig. 8.3a Blood mercury level – adults
Fig. 8.3b Blood mercury level – children
Fig. 8.4a Blood copper level – adults
Fig. 8.4b Blood copper level – children
Fig. 8.5a Blood selenium level – adults
Fig. 8.5b Blood selenium level – children
Fig. 8.6a Blood zinc level – adults
Fig. 8.6b Blood zinc level – children
Fig. 8.7a Polychlorinated biphenyls in breast milk, indicator congener PCB 153
Fig. 8.7b Chlorinated pesticides in breast milk, sum of DDTs
Fig. 8.7c Chlorinated pesticides in breast milk, hexachlorobenzene
Fig. 8.8 Mutagenicity of airborne particulate matter, fraction PM10, winter seasons

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