systemic toxicology

1. Role of toxicological analysis in
biological monitoring
• Presented by Reiam Ameer
• Supervised by dr. ammar ali hussein
• Higher diploma in toxicology
• Baghdad university college of pharmacy

2. Biological monitoring : also termed biomonitoring, is the use of blood, urine, or other
human samples to assess an individual’s state of health, responses to therapeutics, and exposure
to chemicals, or other environmental agents of concern. Biomonitoring is of considerable
potential value to assess military exposures and possible contributions to health outcomes.
two different forms of Biological Monitoring
1.Biological Monitoring of the internal dose (analysis of chemicals or their metabolites in blood
or urine) .
2.Biological Monitoring of the effective dose (haemoglobin adducts in blood and DNA adducts in
blood or urine) .

4. Principal Monitoring Methods
• Biological monitoring of exposure is based on the determination of indicators
of internal dose by measuring:
• the amount of the chemical, to which the worker is exposed, in blood or urine
(rarely in milk, saliva, or fat).
• the amount of one or more metabolites of the chemical involved in the same
body fluids.
• the concentration of volatile organic compounds (solvents) in alveolar air.
• the biologically effective dose of compounds which have formed adducts to DNA
or other large molecules and which thus have a potential genotoxic effect.

5. Analytical methods for the determination of biomarkers of
exposure to phthalates in human urine samples
• This study presents an overview of the analytical methods for the determination of
biomarkers of exposure to phthalates in human urine samples. Phthalates are
nonpersistent chemicals; hence, urine is the ideal matrix for biomonitoring besides
being noninvasive and simple to collect. Phthalate monoesters and oxidative secondary
metabolites are the suitable biomarkers of exposure to short- and long-chain
phthalates, respectively. The determination of urinary phthalate metabolites
significantly reduces the "phthalate blank problem," which arises due to the ubiquitous
presence of this chemical compound in laboratory atmosphere. Sample preparation and
analytical methodologies for the determination of urinary phthalate metabolites by gas
chromatography-mass spectrometry (GC-MS) and liquid chromatography- tandem mass
spectrometry (LC-MS/MS) techniques were discussed. Issues on the validity of urinary
phthalate metabolite data, such as intra- and interpersonal variations, variability in
population subgroups, and variability due to time and type of urine sample collection,
are discussed. Measures to minimize uncertainties associated with urinary phthalate
metabolite concentration are also suggested.

6. General scheme of human biomonitoring of phthalates by
urinary metabolite analysis.

7. The relationship between environmental, biological and
exposure monitoring, and health surveillance

8. Exposure Monitoring
Exposure monitoring is conducted to evaluate workplace health and safety
conditions as they relate to workers' exposures to chemical, physical, and
biological hazards during the time they are in the working environment.
Monitoring assists management in selecting and implementing effective
workplace engineering controls; developing administrative controls; and
selecting, using, and determining the limitations of personal protective
equipment.

9. Health Surveillance
• “Periodic medico-physiological examination of exposed workers withthe objective
of protecting health and preventing disease”

10. environmental monitoring
• When a toxic substance (an industrial chemical, for example) is present in the
environment, it contaminates air, water, food, or surfaces in contact with the skin;
the amount of toxic agent in these media is evaluated via environmental
monitoring.
•Biological Monitoring
• “the measurement and assessment of agents or their metabolites either in
tissues, secreta, excreta, expired air or any combination of hese to evaluate
exposure and health risk compared to an appropriate reference”.

11. Blood, Breath or Urine?
• Breath and urine should be used preferentially
• Accurate breath sampling and analysis using a transportable respiratory mass
spectrometer – not always available
• Breath not always convenient (smokers etc)
• Urine samples affected by:
– Concentration (hydration levels), time of day
– Required commitment to collect samples (24 hours)
– Variability in subjects, metabolism , body weight etc.

13. Setting Up Biological Monitoring
• 1.Purpose of the survey/programme (health surveillance/exposure monitoring?)
• 2.Competent person to manage it (someone who understands the guide/access
to specialist expertise – blood samples)
• 3.Define the strategy
• 4.Consult with employees / representatives
• 5.Discuss and agree programme/survey with employees
• 6.Establish procedures for collection, storage, transport and analysis of samples –
quality assurance
• 7.Establish procedure for feedback, including interpretation of results
• 8.Ensure arrangements in place for acting on the results and evaluation
effectiveness of programme

14. Focused Assessment
• Advantages
• Extended exposure time
• Mobile worker
• Absorption of substance by number of routes
• All sources – occupational and environmental
• Work effort, ventilation, climate factors in quantity absorbed
• Limitations
•Small number of substances Are results from current or historical exposure (Cd and Hg)
• Degree of exposure not organ burden
• Metabolism interferences
• Alcohol
• Smoking

15. Information Required for the Development of
Methods and Criteria for Selecting Biological Tests
• Programming biological monitoring requires the following basic conditions:
1. knowledge of the metabolism of an exogenous substance in the human
organism (toxicokinetics)
2. knowledge of the alterations that occur in the critical organ (toxicodynamics)
3. existence of indicators
4. existence of sufficiently accurate analytical methods
5. possibility of using readily obtainable biological samples on which the
indicators can be measured
6. existence of dose-effect and dose-response relationships and knowledge of
these relationships
7. predictive validity of the indicators.

16. Relationship between exposure, internal dose and
effects
• Knowledge of the relationships between the dose of a substance and the
effect it produces is an essential requirement if a programme of
biological monitoring is to be put into effect. The evaluation of this dose-
effect relationship is based on the analysis of the degree of association
existing between the indicator of dose and the indicator of effect and on
the study of the quantitative variations of the indicator of effect with
every variation of indicator of dose
• With the study of the dose-effect relationship it is possible to identify the
concentration of the toxic substance at which the indicator of effect
exceeds the values currently considered not harmful. Furthermore, in
this way it may also be possible to examine what the no-effect level
might be.

17. Practical Applications of Biological Monitoring
• The practical application of a biological monitoring programme requires
information on
• (1) the behaviour of the indicators used in relation to exposure, especially those
relating to degree, continuity and duration of exposure,
• (2) the time interval between end of exposure and measurement of the
indicators, and
• (3) all physiological and pathological factors other than exposure that can alter
the indicator levels.

18. Advantages of Biological monitoring
1. It helps in assessing exposure and harmful effects of chemical received by a
worker by all routes .i.e. Inhalation through breath, absorption through skin,
intake through mouth etc.
2. Past exposure too diagnosed by the biological monitoring.
3. Exact exposure to individual can be assessed as it is individual sampling method.
4. If any synergistic effect happening can also be diagnosed during monitoring.
5. Recent advance technologies like scalp sampling help in determining long past
drugs intake easily whereas other samplings can not do this.
6. Exposure of worker in total can be determined which means if worker is moving
or working at different stations then biological monitoring can determine exact
amount of exposure.
7. Both workplace and non workplace related exposure can be assessed.

19. Dis advantages of Biological monitoring
1. are usually unable to specify the source of the exposure (occupational or
non-occupational);
2. may not be sufficiently specific to a particular chemical;
3. are not suitable for identification of workplace contaminations in general;
4. may be interfered by other chemicals in the biological medium (e.g.
medications);
5. are not useful at all for the assessment/monitoring of acute and/or local
toxic effects (e.g. irritation);
6. and the provision of samples for biomonitoring may be a burden for
workers (e.g. blood samples).

20. different analytical techniques like
• tandem mass spectrometry
• chromatographic techniques
• chromatography by silica-gel chromatobars
• Ultra-high performance liquid chromatography-tandem mass
spectrometry,
• DNA typing
• capillary electrophoresis
• immunoassays

21. Summary:
• Biological monitoring is a useful adjunct to environmental monitoring
(occupational)
• Measures exposure by ALL routes (how much absorbed)
• Exposes potential failures in control measures particularly where reliance is on
PPE/RPE, also where control adequate
• To evaluate implementation of controls and if improvements have reduced
exposure
• Can provide useful baseline information for long term cumulative exposure
studies
• Limited to specified substances
• Indication of exposure where OEL not exceeded
• Provides reassurance to workers that their personal exposure is under control

23. Case study: Benzene exposure to workers during tunnelling

24. The Problem
• A main tunnel was under construction, as part of upgrades to the Belfast
wastewater and sewers infrastructure, on the site of a former gas works.
• Soil samples had indicated the presence of various volatile organic chemicals, of
which benzene was the major component. Initial monitoring (using both air and
biological sampling) showed that benzene exposure was being well controlled,
however, benzene levels began to rise rapidly; well in excess of the UK workplace
exposure limit.
• This corresponded with a rise in temperature (early May) and workers were
complaining about the heat and were sweating profusely inside their suits. A
small number exhibited signs of what was believed to be heat stress/dehydration.

25. What We Did
• We measured a specific metabolite of benzene called S-phenyl mercapturic acid (SPMA) in a
urine sample from exposed workers. A guidance value (equivalent to an 8-hour exposure at the
workplace exposure limit) allowed us to interpret the results.
• In response to the high temperatures, workers had been provided with additional bottled
water. However, the subsequent series of biological monitoring results showed significant
benzene exposure with 20% of samples exceeding the guidance value for urinary SPMA; in the
worst case by over 10 fold.
• On investigation, it was found that due to the heat and the need to drink water more
frequently, workers had been removing their PPE in the tunnel during work, when leaving the
tunnel at break times, and at the end of their shifts. Some also reported taking off their
respirators to answer their mobile phones.
• A decision was taken to stop working and during this time a chiller was installed to improve
working comfort. PPE was upgraded and changes were made to working practice.
• Work resumed with at least weekly biological monitoring. Prompt analysis and reporting of the
results allowed site management to quickly intervene if biological monitoring indicated a
reduction in exposure control. Following these improvements, a dramatic reduction in SPMA
levels was seen, with only three results out of 432 (0.7%) exceeding the guidance value.

26. Outcome/Benefits
• This case study illustrates the value of biological monitoring in situations where control
of exposure primarily relies on RPE and other PPE. Although air monitoring had
identified 'hot spots' of contamination, the intermittent nature of these pockets of
benzene contamination and the extensive use of PPE meant that it was not sufficient to
assess the risk of exposure.
• Biological monitoring was able to give an integrated measurement of actual systemic
exposure (despite the PPE) and highlight issues with both the PPE and its use.
Furthermore, since biological samples are specific to an individual, it enabled the
identification of any human factors that might influence exposure control.
• The improvements to control measures and working practice, in light of the elevated
biological monitoring results, resulted in significant reductions in worker exposure to
benzene. Thus biological monitoring enabled the job to be completed whilst giving
assurance that the workforce was not being exposed to potentially hazardous levels of
benzene.

27. References:
• Encyclopaedia of occupational health and safety(fourth edition)
• Indian journal occupational &environmental medicine
• iosh.com
• Health and safety executive (case study)