ABSTRACT
In general, risk assessments of urban soil pollution are prepared by comparing the levels of pollutants with soil quality criteria. However, large urban areas are contaminated with concentrations of pollutants far exceeding the existing soil quality criteria and would consequently be considered to be of potential risk to humans. This is, however, a rather rigid approach, and for risk management purposes it would be desirable to have more than just one level of soil quality criteria. Therefore, a generic risk assessment model was developed for five different use scenarios: child-care centers, kitchen gardens, ornamental gardens, parks, and sports grounds. In each of the scenarios, three different types of expected behavior are described for children and adults, respectively, resulting in different levels of exposure to the pollutants. For risk management purposes, various guidance values can then be derived for each use scenario. Below a lower guidance value, a free use of the area according to the defined use is possible without an unacceptable risk to the public. Above an upper value, a cutoff of the exposure is necessary. In between, the use may be regulated by different types of advice. The model is still preliminary but was, however, used for derivation of guidance values for five commonly found soil pollutants, of which the results for benzo[a]pyrene and lead are presented.
Subject(s)
Environmental Exposure , Soil Pollutants , Urban Health , Adult , Benzo(a)pyrene/adverse effects , Benzo(a)pyrene/analysis , Child , Child Day Care Centers , Crops, Agricultural , Humans , Inhalation Exposure , Lead/adverse effects , Lead/analysis , Practice Guidelines as Topic , Recreation , Risk Assessment , Risk Management , Soil Pollutants/adverse effects , Soil Pollutants/analysis , SportsABSTRACT
Of the six types of congenital pseudarthrosis, Type II is the most common and lends to poorest prognosis. The basic pathology is an aggressive osteolytic fibromatosis. Failures in these patients are due to recurrence of the osteolytic fibromatosis, which can remove living bone or a dead bone graft. Type III cases have a better prognosis. The gross pathology is a bone cyst, and the microscopic findings resemble fibrous dysplasia. After surgical treatment, generally, the older the child the better the prognosis. Recurrences are rare after skeletal maturity.
