A non-traditional approach to risk assessment of respiratory exposure to outdoor air pollutants

The aim of this study was to verify a non-traditional assessment of respiratory exposure to outdoor air pollutants in industrial areas. The technique involved environmental biological monitoring' using domestic rabbits in the neighborhood of a mercury-producing plant. Rabbits were exposed whole-body to mercury emissions for 6 months in special cages near the plant. Control rabbits were kept using the same schedule outside the polluted area. Potential toxicity was assessed by: (a) measurement of Hg-accumulation in lungs and other body tissues by atomic absorption spectroscopy (AAS); (b) scanning electron microscopy (SEM) of the tracheal surface; and (c) measurement of toxic effects on pulmonary alveolar macrophages (PAM) by a rossette assay (Fc immunoglobulin binding). We found increased Hg concentrations in the lungs, kidneys, liver, heart, brain and bone; changes in the mucosal relief of the trachea, and depression of PAM Fc receptor (FcR) activity to IgG. A 6-month chamber exposure of Wistar rats to the aerosol created from solid particles of the mercury-producing plant revealed the increase of Hg-content in the same body tissues except the brain, and, less intense morphologic changes on the tracheal relief. Biomonitoring using environmental exposure of domestic rabbits might be useful in screening for possible health hazards to the respiratory system from complex outdoor aerosols.

Different growth response of Euglena gracilis to Hg, Cd, Cr and Ni compounds

The toxicity of inorganic mercury, nickel, chromium and cadmium on the unicellular photosynthetic flagellate Euglena gracilis, strain Z (E.g.) has been tested. Under the conditions used each metal impaired the growth rate of E.g., and had a very strong effect on cell motility. The degree of cytotoxicity and motility decreased from mercury iodide to cadmium chloride to cadmium nitrate to potassium dichromate to nickel sulfate. No mutagenic effects of the metals investigated have been observed. Adverse effects of metal compounds can be tested on the eukaryotic species of Euglena gracilis used as an intermediate model system between bacterial and animal model.