3. ORGANIZATION OF THE MONITORING SYSTEM |
3.1 Scope of the Monitoring System
The Monitoring System has been implemented in 30 localities including the capital Prague, selected district cities and the former regional capitals. Not all subsystems of the Monitoring System have been in operation in all cities since, in some cases, representative information could be obtained from a lower number of localities (e.g. dietary exposure and biological monitoring) as well as for economic reasons.
Data on the implementation of different monitoring subsystems and on the quality of the living conditions and of the environment in different localities together with demographic data are summarized in Fig. 3.1 and Tab. 3.1. (Atlas of the Environment and Population Health in the Czech and Slovak Federal Republics, 1992). A positive result is that in the course of six years of routine operation, no changes in the number of participants under monitoring have occurred. This means that the whole system can be considered to be stabilized and regular from the point of view of the scope of the monitoring activities.
3.2 Monitored factors and their limits
A set of factors (pollutants, contaminants, analytes and indicators) have been monitored in the individual subsystems. Their list is based on the respective standards and analyses carried out prior to the actual start of the Monitoring System and was last optimized in the Amendment to the monitoring subsystem projects. The factors, pollutants, contaminants and subsystems intended for monitoring are listed in the Supplement. In addition, the critical parameters or limit values, if established, are given.
For the evaluation of results in the subsystems, several types of limits have been applied. On the one hand, they are limits given in our standards and public notices and on the other hand, they are values adopted from presentations of international institutions (e.g. the World Health Organization), which do not always have to have normative validity in our country. In question are namely exposure limits of the acceptable daily intake type, or recommended daily intake in the evaluation of exposure to contaminants or trace elements from foodstuffs or drinking water, or tolerable internal doses in evaluating the content of toxic substances in biological material. In the course of the existence of the Monitoring System, a natural development in the formulation of these critical quantities has been taking place, just as in the determination of their numerical values, and therefore their changes are reflected in the Special Reports and the Summary Report.
3.3 Information system of the Monitoring System and processing of results
The structure of databases and sets of corresponding computer codes ensure the collection of results at the end users of the information system (measuring laboratories), their transport to the directors of the individual subsystems, and their independent processing according to the requirements of the users of the Monitoring System. The directors archive all original information in separate databases to enable their reprocessing according to other criteria. The databases are designed as standard products allowing data processing to the usual extent. They are compatible with other database systems and allow additional data processing and evaluation if required.
The quantitative data processing is based on the calculation of the parametric sample characteristics (arithmetic and geometric mean, standard deviation) or the nonparametric ones (median, quantile). Most information on pollutant concentrations in an environment showing a statistical distribution closes to the lognormal one are processed in this way. Both the detection limit of the analytical method used and the extreme values due to a specific high burden in a locality or population (so called non-systematic fluctuations) are to be taken into account. If the burden does not show a normal distribution, an arithmetic mean of the values obtained does not reflect the situation appropriately. Therefore it seems more appropriate and more objective to use the nonparametric sample characteristics (median, quantile), thus avoiding any wrong assumptions as for the statistical distribution of the processed data. It should be noted that the calculation of individual statistical characteristics is limited by the number of values in the sample processed. In case of their small numbers, the mean value (mean and median) is presented only.
Nevertheless, the application of the nonparametric characteristics has not yet been generalized. The reason is that some standard or reference data are still presented as arithmetic means, thus giving overestimated values. In the databases of Monitoring System, the characteristics of all types of information are available and one of the goals is to achieve a progressive transition to a nonparametric concept of expressing the results.
In many cases, in a series of values obtained on the concentration of a contaminant (analyte) in some medium (the environment or biological material), there is a greater number of results below the detection limit (so called “negative results” or “trace amounts”). It is difficult to evaluate such a situation quantitatively. As far as a measured concentration being below the detection limit, for the calculation of sample characteristics a value equaling one-half of the detection limit is used. Often, there also occurs a situation in which in a series of values measured there is a greater number of results falling below respective detection limits. Further processing of such data can be loaded with an error, which, from the point of view of the value of exposure, is not substantial because, in principle, it is presented at the bottom of the exposure limit range. In the cases where the number of negative measuring exceeds 50 % of the total number of analyses, such trace amounts are usually described verbally only and a quantitative evaluation of the results is not always performed.
Results presented in previous Summary Reports were accompanied by information on previous years. In the present Summary Report, for greater clarity, previous data are summarized under the term “Range 1994/99” giving the maximum and minimum of mean concentrations or exposure values registered in the years 1994 through 1999 in charts for each specific factor (contaminant). Along with current characteristics (e.g. median and 90% quantile) for the year 1999 one can get an idea of the exposure of the population to individual contaminants during the whole period of routine operation of the Monitoring System.
For this year’s Summary Report, there was carried out for the first time an evaluation of the trends of factors under follow-up in each of the environment components studied in the mentioned period of 1994 through 1999. The evaluation was materialized through the correlation coefficient for an isolated assessment of data series, e.g. on the development of the concentration of a certain contaminant over time, or by analysis of variance in more complicated situations. Evaluations are usually carried out at the 5% level of significance (p < 0.05) if not indicated otherwise. In retrospective, graphic illustrations, a positive or negative trend (a statistically significant rise or fall in values over time) is indicated by a symbol (“+” or “-”) above or below the range of evaluated data. For situations where the hypothesis of random distribution of the values is not ruled out, no symbol is given.
When repeatedly analyzing time correlation of the values, two data sets
are obtained: first for the period 1994 - 1998 and second for the period
1994 - 1999. It is evident that for such a low number of values (five and
six, respectively) evaluated, it can be relatively frequently found that
correlation for the period 1994 - 1998 may not be confirmed for the period
1994 - 1999. This can due to the usual variation of values within the set
evaluated. Another explanation of these differences between the results
consists in the principle of correlation evaluation itself. Estimation
of the correlation coefficient is based on the presumption of a linear
trend of the results evaluated and this presumption may not be correct
in all situations, since decrease of exposure or burden of the population
may not be linear in this phase. Probably, it will approximate exponentially
a value which will represent a limit burden, further decrease of which
will be neither realistic nor necessary from the point of view of the relation
to the exposure limits (about 1 % of the limit). Evaluation taking into
account possible nonlinear courses of exposure or burden of population
in time is foreseen for the next period of monitoring.
3.4 QA/QC system
Quality assurance (QA) and quality control (QA) in analytical laboratories participating in the Monitoring System are components of the activities of the laboratories alone and their supervising organizations (public health services, private laboratories). Information on QA/QC activities of the directors of different subsystems is presented in Special reports. Quality assurance analysis in the laboratories of the Monitoring System is based on the interlaboratory comparison of sample analyses (circular sample analysis), use of reference materials for internal control and regulatory diagram and appropriate keeping of documentation records.
The QA/QC program is supervised by the independent working group, which carries out the special audits. Conclusions of these audits are not commonly published and are intended for participating laboratories to improve their work. The procedures used by the working group induce the laboratory staffs to obtain controllable and comparable results. Communication between the laboratories and QA/QC working group is at a good level and helps in materialization of monitoring activities.
BIOLMON, the Manual for Controls of QA of Analyses for laboratories, written by the extended working group at the beginning of its activities, is a very suitable tool providing guidance for activities of the laboratories. The Manual for Controls of QA (not to be confused with the Manual of Quality for Accreditation Procedures) vectors the laboratory staff for the creation of conditions for their activities to be transparent, for assurance of high quality results, tracing the fate of samples processed in the past and provision of those for possible arbitration procedures. Although simpler than the Manual of QA, the Manual for Controls of QA follows the same principles and provides background data allowing to obtain further certificates of good laboratory practice. The laboratories considered the elaboration of the Manual for Controls of QA as the first step preceding the audit of the working group and, as a rule, are ready to submit it. As many as 99.6 % of the participating laboratories consider this to be helpful for further levels of auditing their good laboratory practice or possible accreditation.
In anticipation of accreditation standards, the QA/QC working group started requiring the standard operation procedures (SOP) for sampling, sample storage and transportation and submission of the results obtained to the Monitoring System Headquarters as an annex to the Manual for Controls of QA. SOP have already been elaborated for sampling and data submission in Subsystems II “Drinking water” and V “Biological Monitoring”. Subsystem IV “Dietary exposure” has been using its SOP from the very beginning of the Monitoring System. Subsystem I “Air” has its SOP partly elaborated and Subsystem III “Noise” uses its own QA/QC system.
Furthermore, the mobile system operated at the National Institute of Public Health within Subsystem I “Air” for measurement of immission concentrations of the major contaminants and some meteorological parameters of outdoor air quality was accredited at the Czech Institute for Accreditation. The QA/QC system needed for materialization of the project “Indoor air quality” was also developed.
In 1999, audits in laboratories involved in measurements of cytotoxicity, biochemical indicators and contaminant contents in selected biological materials were finished. Attention was paid particularly to formal conditions of laboratory activities, such as available staff, area, equipment, sample assurance etc. Both auditing and audited parties gained experience. Possibility of assurance of both internal and external control of laboratory activities was discussed.
Updating of Manual for Controls of QA, neglected by some participating laboratories, was also checked. In conclusion, the heads of the laboratories are recommended to draw attention particularly to the following frequent remarks:
Tab. 3.1 Participants of the System of monitoring the environmental impact on population health
City |
Implementation |
Living |
Environ- |
Code |
Number of inhabi- |
city/ |
|||||
1 |
2 |
3 |
4 |
5 |
district |
city |
|||||
Basic participants: |
|||||||||||
Benešov |
X |
X |
|
X |
X |
A |
3 |
BN |
88.7 |
16.1 |
18.2 |
Brno |
X |
X |
X |
X |
|
C |
3 |
BM |
384.7 |
384.7 |
100.0 |
České Budějovice |
X |
X |
X |
X |
|
B |
4 |
CB |
178.2 |
99.3 |
55.7 |
Děčín |
X |
X |
X |
|
|
C |
5 |
DC |
133.8 |
53.1 |
39.7 |
Havlíčkův Brod |
X |
X |
X |
|
|
A |
2 |
HB |
95.8 |
24.7 |
25.8 |
Hodonín |
X |
X |
|
|
|
A |
4 |
HO |
161.4 |
28.0 |
17.3 |
Hradec Králové |
X |
X |
X |
X |
|
C |
3 |
HK |
161.4 |
99.3 |
61.5 |
Jablonec n/N |
X |
X |
X |
X |
|
B |
4 |
JN |
88.5 |
45.9 |
51.9 |
Jihlava |
X |
X |
X |
|
|
A |
3 |
JI |
109.0 |
52.1 |
47.8 |
Jindřichův Hradec |
|
X |
|
|
|
A |
1 |
JH |
93.8 |
23.1 |
24.6 |
Karviná |
X |
X |
|
|
|
C |
5 |
KI |
284.0 |
66.1 |
23.3 |
Kladno |
X |
X |
X |
|
|
D |
4 |
KL |
150.4 |
71.7 |
47.7 |
Klatovy |
X |
X |
|
|
|
B |
2 |
KT |
88.4 |
23.1 |
26.1 |
Kolín |
X |
X |
X |
|
|
C |
5 |
KO |
95.5 |
30.9 |
32.4 |
Kroměříž |
X |
X |
|
|
|
B |
3 |
KM |
108.7 |
29.9 |
27.5 |
Liberec |
X |
X |
X |
|
|
C |
3 |
LB |
159.4 |
99.8 |
62.6 |
Mělník |
X |
X |
|
|
|
C |
4 |
ME |
94.9 |
19.6 |
20.7 |
Most |
X |
X |
|
|
|
D |
5 |
MO |
119.5 |
70.3 |
58.8 |
Olomouc |
X |
X |
X |
|
|
A |
3 |
OL |
225.7 |
103.4 |
45.8 |
Ostrava |
X |
X |
X |
X |
|
D |
5 |
OS |
322.1 |
322.1 |
100.0 |
Plzeň |
X |
X |
X |
X |
X |
D |
4 |
PM |
168.4 |
168.4 |
100.0 |
Prague |
X |
X |
X |
X |
|
C |
5 |
AB |
1 193.3 |
1 193.3 |
100.0 |
Příbram |
X |
X |
X |
|
|
B |
4 |
PB |
107.6 |
36.9 |
34.3 |
Sokolov |
X |
X |
|
|
|
D |
4 |
SO |
95.0 |
25.8 |
27.2 |
Svitavy |
X |
X |
|
|
|
B |
2 |
SY |
102.5 |
17.4 |
17.0 |
Šumperk |
X |
X |
|
X |
|
A |
2 |
SU |
127.3 |
30.0 |
23.6 |
Ústí n/L |
X |
X |
X |
X |
X |
D |
5 |
UL |
118.7 |
96.5 |
81.3 |
Ústí n/O |
X |
X |
X |
|
|
B |
2 |
UO |
139.3 |
15.2 |
10.9 |
Znojmo |
|
X |
X |
X |
|
B |
2 |
ZN |
114.1 |
36.0 |
31.6 |
Žďár n/S |
X |
X |
X |
X |
x |
A |
2 |
ZR |
125.7 |
24.4 |
19.4 |
Associated participants: |
|||||||||||
Frýdek-Místek |
X |
|
|
|
|
C |
4 |
FM |
228.7 |
62.1 |
27.2 |
Litoměřice |
|
X |
|
|
|
C |
4 |
LT |
114.2 |
25.7 |
22.5 |
Pardubice |
|
X |
|
|
|
C |
4 |
PU |
162.1 |
92.5 |
57.1 |
Remark:
IISŽP - Integrated information system of environment.
City/district - quotient of inhabitants living in the city and in the district.
Codes AB1 - AB10 (A1 - A10 from tech. reasons respectively) are used for individual
districts of Prague.
Evaluation of quality of living conditions and quality of environment,
see Chapter 11.
Number of citizens is actualized at 1. 1. 1999 (Statistical Yearbook
of the CR, 1999).
Fig. 3.1 System of monitoring the environmental impact on population health - Participants