8. HEALTH CONSEQUENCES OF EXPOSURE OF THE HUMAN ORGANISM TO TOXIC SUBSTANCES FROM THE OUTDOOR ENVIRONMENT, BIOLOGICAL MONITORING


8.1 Organization of monitoring activities

Over the period 1994–2003, subsystem V has been materialized in four selected regions, namely Benešov, Žďár nad Sázavou, Plzeň and Ústí nad Labem. Since 2005, biological monitoring has been performed in Ostrava, Prague, Liberec and Zlín (or in Kroměříž and Uherské Hradiště), and includes the monitoring of toxic substances and their metabolites (biomarkers of internal doses), and selected biological changes (biomarkers of biological effects) in the blood and urine of adults (blood donors) and in the breast milk of nursing mothers.

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 were collected by means of a brief questionnaire.

Participating analytical laboratories were subjected to constant quality control of results produced. Inter-laboratory differences have been minimized by defining analyses according to matrix or analyte, respectively. The laboratories involved have had acquired ČIA accreditation. The results on the biomarkers under follow-up are presented in table and box-plot form.

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, the exceeding of those 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 load during a given period. A certain degree of individual variability may be caused by differences in the magnitude of exposure and the individual sensitivity of the human organism to noxae in the environment.

8.2 Factors under follow-up

The basic factors (biomarkers) monitored over the whole monitoring period include toxic metals (cadmium, mercury, lead) and beneficial trace elements (copper, selenium, zinc) in the blood and urine of the adult population. Another significant factor are persisting chlorinated organic substances (indicator congeners of polychlorinated biphenyls – PCBs – and selected chlorinated pesticides) were analyzed in breast milk and on one half of the blood serum samples from adults. In the other half of adult blood serum samples there were monitored levels of the mycotoxin ochratoxin A. The monitoring also included the cytogenetic analysis of human peripheral lymphocytes.

8.2.1 Toxic metals and trace elements

The concentration of cadmium in blood is a biomarker of recent population exposure and is influenced by the smoking habit. The marked significance of tobacco smoking has been repeatedly confirmed also in the Czech adult population, the blood cadmium level in smokers being three times higher that found in non-smokers (Fig. 8.1a). Cadmium levels in the blood of non-smokers in newly followed up cities does not differ from findings obtained in previous periods of monitoring (see Summary Report 2005, http://www.szu.cz/chzp/rep04/szu_05cz.htm). The cadmium concentration in the urine (median 0.33 µg/kg creatinine) does not differ from results obtained in the precious period of monitoring (Tab. 8.1b).

In the course of ten years of monitoring (1994–2003), the concentration of lead in the Czech adult population showed a significant downward trend that led to a re-evaluation (lowering) of reference values. The values of plumbemia in 2005 (Fig. 8.1b) – median value in males 35 µg/L, in females 27 µg/L – does not differ from concentrations found in other cities in the previous period of monitoring (median in males 35 µg/L, in females 25 µg/L).

Likewise, the concentrations of mercury in the blood and urine of adults (Fig. 8.1c; Tab. 8.1a, b) are in conformity with previous monitoring data. Higher values have been demonstrated in females.

Results on the copper content in blood are in line with results obtained in 2003. Higher concentrations have been demonstrated in females (Fig. 8.2a). Likewise, zinc concentrations in the blood of the adult population are in conformity with results obtained in the previous period of monitoring (Fig.8.2b); concentrations of copper and zinc in the urine are presented in Tab. 8.1a, b.

Selenium concentrations in blood found in the year 2005 are in line with results obtained in 2003, exceeding 100 µg/L (Fig. 8.2c) in all the regions under follow-up. Serum concentrations of selenium in the range of 90–150 µg/L are considered to be the optimum. The coefficient 0.8 should be used in calculations of values in whole blood. That means that the saturation of the Czech population with selenium has not reached optimum levels yet. Selenium levels in the urine suggest an increasing trend (Tab. 8.1a, b).

8.2.2 Toxic substances of organic origin

Systematic monitoring was performed in polychlorinated biphenyl (PCB) indicator congeners and selected chlorinated hydrocarbons in breast milk. Results confirm the predominance of PCB congeners 138, 153 and 180, as well as that their levels increase with age. Higher values have been found in the area of Uherské Hradiště (Fig. 8.3a). DDT concentrations with a predominant share of DDE in the resulting value (median 355 µg/kg fat) are comparable with results in other areas found in the year 2003 (Fig. 8.3b). Concentrations of hexachlorobenzene (HCB) in breast milk (median 66 µg/kg fat; Fig. 8.3c) correspond with the long-term gradual declining trend in chlorinated pesticides.

In 2005, PCB indicator congeners and selected chlorinated pesticides have been analyzed also in samples of blood serum. As yet, no temporal series can be drawn for such data; the only previous results having been obtained in the year 2002. The PCB indicator congener concentrations confirm, just as in breast milk samples, the predominance of congeners 138, 153 and 180, as well as regional differences (Fig. 8.4; Tab. 8.2). However, concentrations in blood serum reach higher values than those in breast milk, probably due to the age difference between blood donors and mothers.

Roughly 95 % of the sum of DDT (Tab. 8.2) is represented by its metabolite DDE (median = 493 µg/kg fat). In comparison with the year 2002 (median DDE = 709 µg/kg fat) there is a hint of a downward trend now. The concentration of hexachlorobenzene (HCB) in blood serum in 2005 (median = 97 µg/kg fat; Tab. 8.2) signalizes a certain decrease as against results in the year 2002 (median = 169 µg/kg fat).

The concentration of ochratoxin A in blood serum (median 0.20 µg/L; Tab. 8.3) shows balanced values comparable with those in the literature as regards the general population in other countries. The results are by two orders lower than the value which signalizes a risk of nephropathy (> 10 µg/L serum).

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 to indicate the degree of individual tolerance and compensation capacity through defence mechanisms. Values of chromosomal aberrations, that are significantly higher than reference values for each monitored population group may thus reveal any significantly increased exposure to genotoxic substances from the communal environment. Existing data shows that values for chromosomal aberrations in adult population groups obtained in newly monitored areas of the Czech Republic (Tab. 8.4) confirm the rising trend observed since 2001 (following a transient decline in the years 1994–1999). The causes of that rise have to be carefully analyzed in relation to the level of the exposure load from the environment as well as in relation to the intake of protective substances in a balanced diet.

8.4 Partial conclusions

The results of biological monitoring in newly studied regions are mostly in line with data obtained in the previous period of monitoring as well as with results in other European countries. Concentrations of toxic elements in the blood and urine are stable. Confirmed has been the improving saturation of the adult population with selenium. A downward trend is apparent in the burdening with the group of persistent chlorinated organic compounds (PCB, DDT, HCB).

Results of analyses of indicator PCBs and chlorinated pesticides in blood serum are in continuation of data obtained in the year 2002 and form the basis for a long-term temporal series of data. A significant role in that load plays age and a differing local or individual exposure level in the past.

The rising trend in values of chromosomal aberrations, or a return to values that were usual up to the year 1989, as observed over the past five years, signalizes an increasing load in the Czech population with substances and factors having a genotoxic effect, and that requires a more detailed analysis of the potential causes of that.

Tab. 8.1a Concentration of metals and metaloids in urine of adults, 2005 [µg/L urine]

 

Cd

Pb

Hg

Cu

Zn

Se

Total

N

278

278

278

278

278

278

Me

0.46

4.10

1.60

7.40

357.00

16.00

P95

1.53

12.00

9.30

18.00

844.00

30.00

Vmax

2.90

19.00

60.00

397.00

2,427.00

48.00

Vmin

0.05

0.80

0.03

0.75

14.00

5.60

Prague

N

73

73

73

73

73

73

Me

0.41

4.40

1.80

7.20

337.00

20.00

P95

1.20

10.40

8.30

18.00

756.00

34.00

Vmax

2.70

14.00

19.30

31.00

1,186.00

48.00

Vmin

0.05

0.80

0.03

0.75

14.00

5.60

Liberec

N

62

62

62

62

62

62

Me

0.72

5.40

1.50

8.00

304.00

16.00

P95

1.60

9.90

10.90

16.00

722.00

27.00

Vmax

2.20

16.00

51.00

34.00

2,427.00

35.00

Vmin

0.05

0.80

0.07

3.00

38.00

6.70

Ostrava

N

64

64

64

64

64

64

Me

0.40

5.50

1.30

7.40

407.00

14.00

P95

1.50

13.20

7.70

75.00

852.00

27.00

Vmax

2.00

19.00

12.80

397.00

1,336.00

34.00

Vmin

0.05

0.80

0.10

0.80

109.00

6.30

Kroměříž

N

39

39

39

39

39

39

Me

0.28

2.80

1.80

7.40

408.00

15.00

P95

0.99

6.70

12.00

18.00

838.00

25.00

Vmax

1.50

8.20

14.00

21.00

1,121.00

29.00

Vmin

0.05

0.80

0.03

0.80

101.00

6.70

Uherské Hradiště

N

40

40

40

40

40

40

Me

0.32

2.60

1.50

7.20

484.00

14.00

P95

2.00

4.40

16.00

11.00

939.00

29.00

Vmax

2.90

5.80

60.00

22.00

971.00

33.00

Vmin

0.05

0.80

0.17

0.80

138.00

6.20

Tab. 8.1b Concentration of metals and metaloids in urine of adults, 2005 [µg/g creatinine, range of creatinine content 500–2,800 mg/L]

 

Cd

Pb

Hg

Cu

Zn

Se

Total

N

278

278

278

278

278

278

Me

0.33

3.00

1.30

5.20

275.00

12.00

P95

1.09

10.90

8.00

13.00

533.00

30.00

Vmax

4.90

17.00

41.00

221.00

2,780.00

64.00

Vmin

0.02

0.30

0.02

0.38

12.00

2.80

Prague

N

73

73

73

73

73

73

Me

0.33

3.90

1.50

5.90

289.00

14.00

P95

0.98

10.90

6.60

11.00

518.00

34.00

Vmax

2.60

13.00

8.30

30.00

732.00

64.00

Vmin

0.02

0.30

0.04

0.42

12.00

2.80

Liberec

N

62

62

62

62

62

62

Me

0.54

3.80

1.20

6.30

248.00

13.00

P95

1.32

11.10

8.70

13.00

439.00

27.00

Vmax

4.00

16.00

30.00

26.00

2,780.00

30.00

Vmin

0.02

0.30

0.07

2.00

52.00

3.20

Ostrava

N

64

64

64

64

64

64

Me

0.39

3.50

1.00

4.90

307.00

10.00

P95

1.07

12.90

5.20

46.00

630.00

31.00

Vmax

1.50

17.00

11.40

221.00

759.00

36.00

Vmin

0.02

0.30

0.10

0.40

83.00

2.80

Kroměříž

N

39

39

39

39

39

39

Me

0.17

1.40

1.30

4.20

243.00

8.40

P95

0.62

5.40

5.30

12.00

398.00

18.00

Vmax

0.93

6.40

10.00

13.00

898.00

19.00

Vmin

0.02

0.30

0.02

0.50

54.00

3.10

Uherské Hradiště

N

40

40

40

40

40

40

Me

0.27

1.60

1.10

4.50

319.00

10.00

P95

1.14

4.70

12.00

8.00

512.00

22.00

Vmax

4.90

7.00

41.00

16.00

603.00

31.00

Vmin

0.02

0.30

0.13

0.40

83.00

3.00

Legend for Tables 8.1a, 8.1b:

N – no. of individuals
Me – median
P95 – 95
th percentile
V
max – maximum value
V
min – minimum value

Tab. 8.2 Chlorinated pesticides and polychlorinated biphenyls (PCBs) in blood serum of adults, 2005 [µg/kg fat]

 

HCB

DDTs

PCB153

PCB138

PCB180

PCBs*

Fat content

Total

N

199

203

203

203

203

203

203

Me

97

519

438

188

397

1,760

0.38

P95

630

1,688

1,079

520

1,134

4,543

0.64

Vmax

3,790

5,418

2,280

965

2,210

9,122

1.81

Vmin

4

50

64

13

43

303

0.08

Prague

N

51

52

52

52

52

52

52

Me

123

459

314

145

219

1,153

0.40

P95

654

1,461

922

407

658

3,401

0.58

Vmax

3,790

5,418

1,360

574

1,060

5,068

0.75

Vmin

4

112

85

13

43

303

0.20

Liberec

N

50

50

50

50

50

50

50

Me

68

363

359

146

315

1,394

0.46

P95

298

860

755

356

659

3,205

0.64

Vmax

482

1,688

988

476

936

3,851

0.77

Vmin

23

149

64

34

84

309

0.24

Ostrava

N

47

50

50

50

50

50

50

Me

96

680

545

268

491

2,130

0.29

P95

464

1 923

1,097

565

1,272

4,973

0.56

Vmax

891

3,366

1,740

965

1,480

6,550

0.78

Vmin

8

50

201

87

131

830

0.08

Kroměříž

N

26

26

26

26

26

26

26

Me

104

639

442

186

458

1,887

0.35

P95

771

1,636

659

300

710

2,837

0.62

Vmax

1,450

4,020

750

347

834

3,138

0.72

Vmin

16

259

155

69

147

631

0.22

Uherské Hradiště

N

25

25

25

25

25

25

25

Me

145

725

669

297

634

2,846

0.35

P95

762

1,981

1,722

664

1,852

7,204

0.76

Vmax

931

4,977

2,280

876

2,210

9,122

1.81

Vmin

48

303

324

153

283

1,350

0.13

* Sum of indicator congeners (PCB 153, 138, 180)*1.7

Legend for Table 8.2:

N – no. of individuals
Me – median
P95 – 95
th percentile
V
max – maximum value
V
min – minimum value
HCB – hexachlorobenzene

Blood serum is the clear liquid that is separated by centrifugation from the blood after clotting. It is therefore blood plasma from which fibrinogen and some coagulation factors have been removed.

Tab. 8.3 Concentration of ochratoxine A in blood serum [µg/L]

 

Total

Prague

Liberec

Ostrava

Kroměříž

Uherské
Hradiště

N

202

52

50

50

25

25

Xa

0.20

0.24

0.20

0.21

0.19

0.13

Me

0.20

0.20

0.20

0.20

0.20

0.10

P95

0.40

0.40

0.46

0.40

0.30

0.20

Vmax

2.30

2.30

0.80

0.70

0.70

1.00

Vmin

0.05

0.05

0.05

0.05

0.05

0.05

Tab. 8.4 Chromosomal aberration levels [share of aberrant cells, %]

 

Total

Prague

Liberec

Ostrava

Kroměříž

Uherské
Hradiště

N

381

102

79

100

50

50

Xa

1.81

1.66

2.17

1.81

2.24

1.14

SD

1.31

1.11

1.33

1.25

1.71

0.91

Me

2.00

1.50

2.00

2.00

2.00

1.00

P95

4.00

3.50

4.10

4.00

4.78

2.60

Vmax

9.00

5.00

6.00

5.00

9.00

5.00

Vmin

0.00

0.00

0.00

0.00

0.00

0.00

Legend for Tables 8.3, 8.4:

N – no. of individuals
X
a – arithmetic mean
SD – standard deviation
Me – median
P95 – 95
th percentile
V
max – maximum value
V
min – minimum value


Fig. 8.1a Blood cadmium level in adults, 2005
Fig. 8.1b Blood lead level in adults, 2005
Fig. 8.1c Blood mercury level in adults, 2005
Fig. 8.2a Blood copper level in adults, 2005
Fig. 8.2b Blood zinc level in adults, 2005
Fig. 8.2c Blood selenium level in adults, 2005
Fig. 8.3a Polychlorinated biphenyls in breast milk, 2005 (Sum of indicator congeners PCB 138, PCB 153, PCB 180)
Fig. 8.3b Sum of DDTs in breast milk, 2005
Fig. 8.3c Hexachlorobenzene in breast milk, 2005
Fig. 8.4 Sum of PCBs in blood serum of adults, 2005

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