In the founding years of the University of Siegen, the use of polychlorinated biphenyls, or PCBs for short, was standard building practice. At the beginning of the 2000s, the first information about the use of these building materials at the university became known, and individual parts of the building therefore have elevated PCB levels. With regard to PCBs, health impairments cannot be ruled out if high concentrations are ingested over a long period of time.
The responsibility for removal lies with the Bau- und Liegenschaftsbetrieb (BLB) NRW as the owner of the buildings and the University of Siegen as the employer.
Although there is no acute health risk due to the measured values, the university is taking the concerns seriously and is acting together with the BLB to protect and inform students and employees in the best possible way. This includes continuous measurements and transparency, measures to reduce PCB levels as well as individual advice and services.
On this portal you will find extensive information on PCBs, the situation at the University of Siegen and preventive measures to reduce exposure in affected rooms.
Information on PCB
PCB is the abbreviation for "polychlorinated biphenyls", a large group (the 209 different substances are referred to as "congeners") of aromatic compounds that are difficult to break down and are polychlorinated. Due to their special properties such as high heat and chemical resistance, low vapor pressure, low flammability and low electrical conductivity, they have been used in a wide variety of technical applications in the past.
The majority of PCBs were used in insulating and hydraulic fluids in so-called closed systems. However, they were also used in insulating and sealing compounds, additives in paints and varnishes to improve spreadability and as impregnating and flame retardant agents (open systems).
The use of PCBs in open systems has been banned in Germany since 1978, and there has been a general ban on their manufacture and use in Germany since 1989. However, these substances have accumulated in the environment through years of use and due to their longevity and are constantly ingested by humans. The majority of PCB intake (60-90%) occurs through food, especially animal fats.
To a lesser extent, PCBs are also absorbed through the air. Outdoor air pollution in urban areas is around 100 ng/m3. However, indoor air pollution can be higher if PCB sources are present. These can be present in joint materials and sealants, flame retardants or plasticizers in plastics that were used in buildings up to 1978. Typical building materials containing PCBs are
- Building separation joints
- Movement joints between precast concrete elements
- Glass connection joints on windows
- Connection joints (windows, door frames)
- Paint and adhesives
- Ceiling tiles (with plasticizers or flame retardants)
- Cable sheathing.
With regard to the urgency of measures for permanently used rooms, recommendations have been made which are listed in the NRW PCB guideline:
- Values below the so-called precautionary value of 300 ng/m3 in indoor air are to be regarded as tolerable in the long term.
- In a concentration range between 300 and 3,000 ng/m3 , the PCB source must be tracked down and eliminated in the medium term, taking proportionality into account. In the meantime, the PCB concentration must be reduced by regular ventilation and thorough cleaning with a target value 300 ng/m3.
- If the intervention value of 3,000 ng/m3 is exceeded, acute health hazards must be assumed that require immediate measures, with a target value 300 ng/m3.
- In addition, there has been a limit value for dioxin-like PCBs since 2007. If the levels exceed the value of 10 ng PCB 118 / m³ air (PCB 118 is an indicator PCB for dioxin-like PCBs), exposure-reducing measures are required in accordance with the Ad Hoc Working Group Indoor Air Hygiene Commission of the Federal Environment Agency and the highest state health authorities.
The listed concentration ranges are based on the assessment of the body's PCB intake during a 24-hour stay in the rooms concerned. With a standard working time of eight hours, this results in an acceptable exposure value of 900 ng/m³. In seminar rooms, the average length of stay is usually significantly lower.
When evaluating the results of indoor air measurements, it should be noted that PCB concentrations are highly temperature-dependent. In the summer months, significantly higher levels are recorded.
Personal factors such as body weight, metabolism and time spent in a contaminated room are also decisive in assessing the risk to an employee.
Biomonitoring studiescan provide information on the individual exposure situation.
can provide information.
The effects of long-term inhalation of PCBs on health have not yet been fully clarified scientifically. Possible dose-dependent effects on the nervous system, immune system, hormone balance, skin, liver, metabolism and cancer development are suspected from accidents with high-dose PCBs and animal experiments.
Special precautions apply to pregnant women, people with chronic illnesses and immunosuppressed persons. Anyone who belongs to this group of people and regularly spends long periods of time in the affected parts of the building is asked to contact Department 1.1 - Occupational Health and Safety. The contact person is Andrea Mahle, e-mail: andrea.mahle@zv.uni-siegen.de, extension: -Employees who have worked in highly contaminated areas for many years can also seek advice here.
Situation at the University of Siegen
The majority of the buildings on the Adolf Reichwein Campus were constructed in the 1970s. During this time, building materials containing PCBs were generally used in their construction, and consequently some of these buildings still contain PCBs today.
Together with the SU, the University of Siegen has taken measures to protect students and staff in the best possible way. This includes partially removing contaminated areas from use. Furthermore, remediation measures have been carried out in which PCB sources have been removed. This has minimized the potential risk.
Individual rooms on the Adolf Reichwein Campus still have PCB levels of more than 300 ng/m³ (so-called precautionary value, based on a 24-hour exposure period). Individual rooms in building section D on the Emmy Noether Campus are also affected.
The PCB concentration in indoor air is highly dependent on the respective outdoor and indoor temperatures. The higher the temperature, the higher the measured values tend to be. This also means that the orientation of the rooms towards the sun can have a decisive influence.
Technically ventilated rooms (e.g. lecture halls) also have significantly lower levels of PCBs, as the constant exchange of air can reduce the PCB concentration, sometimes considerably. Rooms that have not been used for a longer period of time generally show higher levels of air pollution.
Furthermore, the room contamination is significantly influenced by the quantity and concentration of the PCB-contaminated materials brought in (primary sources) - and by how much of the contamination has been transferred to the fixtures and fittings (e.g. old curtains, cupboards, etc...) (secondary contamination).
Overall, it should be noted that ventilation and cleaning have a strong influence on PCB room concentrations (see also Prevention).
In order to obtain an overview of the type and extent of contamination in the workrooms, the Bau- und Liegenschaftsbetrieb (BLB) has been commissioning and carrying out indicative indoor air measurements since 2004.
In accordance with the PCB guideline
regular control and clearance measurements are carried out in all affected areas throughout the year.
The University of Siegen provides transparent information about the measured pollutant levels and publishes them on the PCB information portal.
PCB remediation has been and continues to be carried out on the basis of investigations carried out continuously since 2004.
There have been several PCB remediation projects in the university area in recent years: Among other things, the transition areas between the PB-C and PB-A parts of the building on the Paul Bonatz Campus have been successfully remediated.
Remediation concepts are always drawn up individually and on the basis of the indoor air measurements and solid samples collected.
In addition to technical and structural solutions to reduce indoor air pollution, there is also the option of preventative short-term measures. In addition to regular ventilation of the rooms, cleaning (see also under prevention) has proven to be particularly effective, as regular cleaning prevents dust from accumulating in the long term.
The PCB-contaminated areas are cleaned regularly by the university. Additional special cleaning is carried out during the lecture-free periods.
Users are also advised to ventilate regularly. The success of these measures is checked in regular control measurements.
On 02.10.2018 at 10:00 a.m. a PCB information event took place in the Alfred-Schaber-Hörsaal (PB-I 001) at the University of Siegen. For legal reasons, the recording of the event is only available on the university intranet. Here you can find the video recording.
Students and employees who have questions about PCBs can contact the Occupational Health and Safety Department at any time (contact person is Andrea Mahle, e-mail: andrea.mahle@zv.uni-siegen.de
extension 4711)
Employees and students who spend long periods of time in rooms with elevated PCB levels every working day can also have their individual exposure situation determined by PCB biomonitoring (see Prevention section ).
Prevention
It has been found that the most effective short-term measure is regular and extensive ventilation of the contaminated rooms. This can significantly reduce PCB exposure. This is also reflected in the low levels of contamination in technically ventilated rooms.
Regular shock and cross ventilation has proven to be particularly effective.
The technical rule for workplaces 3.6 - Ventilation gives the following recommendation for shock ventilation:
- Shock ventilation is defined as the brief (approx. 3 to 10 minutes), intensive exchange of air to remove loads from workspaces.
- Shock ventilation should be carried out at regular intervals as required. Recommended reference values are
- Office room after 60 min
- Meeting room after 20 min
- The minimum duration of shock ventilation depends on the temperature difference between inside and outside and the wind. The following guide values can be assumed:
- Summer: up to 10 min (taking into account the outside temperature)
- Spring/autumn: 5 min
- Winter: 3 min
- If possible, the ventilation time should be approx. 15 minutes at the start of room use.
Due to the surface structure, PCB easily combines with dust. Regular, thorough cleaning reduces long-term deposits. The university's cleaning staff have been instructed accordingly and the cleaning cycle has been adapted.
Before moving out of PCB-contaminated rooms, files, books and inventory are freed from old dust by a cleaning company if necessary.
Special precautions apply to pregnant women and women of childbearing potential as well as people with chronic illnesses and immunosuppressed persons. People who belong to this group and who regularly spend long periods of time in the affected parts of buildings should seek advice from the occupational health and safety department. An individual solution can then be developed together.
To date, there is no reliable evidence of a teratogenic effect in humans. However, based on the results of animal experiments, it must be assumed that there may be negative effects on the unborn child. Exposure of infants via breast milk cannot be ruled out if the precautionary value of 300 ng PCB per m³ of indoor air is exceeded.
The Maternity Protection Act prohibits pregnant women and nursing mothers from working in jobs where they are exposed to harmful effects from substances that are hazardous to health. Harmful effects from PCBs can be assumed if the precautionary value of 300 ng PCB per m³ of indoor air is exceeded - based on a 24-hour exposure period.
The University of Siegen takes the protection of its female employees and students even more seriously: if they work and study in contaminated parts of the building, they are asked to contact the Occupational Safety Department. As soon as knowledge of a pregnancy is available, the necessary measures can be agreed on a case-by-case basis.
Many different criteria must be taken into account when assessing the risk of exposure to PCBs in rooms. In addition to the level of indoor air pollution and the length of time spent in the premises, personal factors such as age, weight, type of activity and physiological characteristics also play a role.
The individual exposure situation of affected employees in the above-mentioned parts of the building can be determined by PCB biomonitoring.
In human biomonitoring, human body fluids and tissues are examined to determine their exposure to pollutants, in this case PCBs. The concentration of the congeners PCB 28, 52, 101, 138, 153 and 180 in blood plasma is measured.
As the concentration of the congeners in blood plasma, especially PCB 28, 52 and 101, is very low and in the range of ng/l (1 billion nanograms is 1 gram), only a few laboratories can carry out a reliable test. It is important that blood sampling and sample processing are standardized.
The University of Siegen has commissioned the Institute of Occupational Medicine and Social Medicine at RWTH Aachen University to carry out the tests.
Those affected can contact Andrea Mahle (e-mail: andrea.mahle@zv.uni-siegen.de).
