However, several international studies respiratory affliction and general symptoms of the
central nervous system, such as fatigue, headaches and problems with the ability to concentrate among
workers at sewage treatment plants. In a minor recent study from STAMI, these finds are confirmed.
National and international studies report of high levels of bacteria and bacterial endotoxins at waste plants.
Exposure to low grade concentrations of hydrogen sulphide can also be present. All of these agents can cause
inflammation of the respiratory system, and negative symptoms of the central nervous system.

The correlation between exposure and health outcome among workers are less examined, especially among
workers handling waste water, such as work at sewage systems and pumping stations, work in ditches
and transport of sewage sludge and septic waste.
The goal of this study is to determine exposure to biological factors and hydrogen sulphate
in waste water plants with new methods. Furthermore we will investigate the connection between
this exposure, and health outcomes such as lung functions, neuropsychological outcome and makers
for inflammations. In order to study the health outcome over time, we plan a follow-up study
after 3 years. From a preventive point of view, we also wish to study the exposure related
determinants in order to develop practical information for activities to reduce exposure.