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Abstract
Assessment of nanoparticle exposure is not an established routine among occupational hygienists. One of the discussions is about methods of quantification, if we should use number concentration, surface concentration or mass concentration for assessment, this is however also influenced by the access to proper measurement equipment. In this paper we discuss five available methods for exposure assessment. One is the Discmini from Testo, which has the advantage that it could be used for personal measurements, but on the other hand has some limitation according to measurement principles; used for Chimney sweepers. Another is the Nanoscan SMPS from TSI, which not is portable for personal measurements, but still is battery operated and could be moved around at a workplace, Nanoscan SMPS measure particle size distribution; this instrument have been used for logbook measurements among Ferrosilicon alloy workers. Number three is the Scanning Mobility Particle Sizer and the Fast mobility particle sizers from TSI , which is large, power demanding and only useable for stationary measurements, but on the other hand highly demandable for quantification. Number four is the Fast Mobility Particle Sizer, also from TSI, with the advantage of 1 second measurements, used in Ferroalloy industry and among Fire fighters. The fifth is the ELPI instrument from Dekati, which enable collection of samples for subsequent analysis on electron microscope, used in Ferroalloy industry. In this poster we compare type of results and discuss the advantages and disadvantages with the different methods and how useful they are for exposure assessment.

POSSM, the PCB On‐Site Spill Model, is a contaminant transport model developed to predict environmental concentrations associated with a chemical spill. The model predicts daily changes in chemical concentrations on a spill site (e.g., in soil and on vegetation) and losses of chemical due to volatilization, surface runoff/soil erosion, and leaching to groundwater. Spill areas consisting of soil/vegetation and/or an impervious surface (e.g., asphalt and concrete) can be analyzed, as can different spill cleanup practices. POSSM is used to analyze exposure levels associated with a hypothetical capacitor spill. While the model was developed for PCB spills, it is generally applicable to a number of organic compounds.

Complex studies were performed combining macroscopic and biochemical analyzes of selected biomonitors, exposed in exposure systems outdoor with mixtures of pollutants as well as controlled exposure with certain concentrations of pollutants in fumigation chambers. In this study, the following plant species were used as bioindicators: Nicotiana tabacum, Petunia hybrida, Ricinus comunis, Trifolium pretense. The exposure plant samples were compared with control samples of biomonitors maintained under standardized conditions in the climate chamber. Classical methods of biochemistry combined with those of exposure biomonitoring have led to the completion of knowledge about the ways of action of plants to pollution. The analysis of some of the antioxidant compounds that are representing a structural class of chemicals (enzymes) with a wide range of biological functions, with the role of free radical inhibition, was performed. Many of the constituent compounds in certain cell types, also called active compounds, in this case, polyphenols are present in the body of some plant species. Polyphenol's presence in organisms, that are not usually present or are in normal quantities, is caused by stress, (pollution being a stress factor). Large amounts of polyphenols in plants are also given by the presence of pollutants in the environment. Through these extensive combined studies, it has been demonstrated that pollution can be a degenerative factor at the biochemical and physiological level, at the plant tissue level, with irreversible effects.

The method of dietary exposure assessment currently used by the Environmental Protection Agency (EPA), the Dietary Residue Evaluation System (DRES), combines a consumption distribution derived from the United States Department of Agriculture (USDA) 1977‐1978 Nationwide Food Consumption Survey (NFCS) with a single estimate of residue level. The National Academy of Sciences'1' recommended that EPA incorporate both the distribution of residues and the distribution of consumption into their exposure assessment methodology and proposed using a Monte Carlo approach. This paper presents an alternative method, the Joint Distributional Analysis (JDA), that combines the consumption and residue distributions, without relying on random sampling or fitting theoretical distributions like the Monte Carlo method. This method permits simultaneous analysis of the entire diet, including assessing exposure from residues in different foods.

Exposure assessment for food and drink consumption requires the combining of information about people's consumption of products with concentration data sets to provide predictions for chemical intake by humans. In this article, we present a method called nonparametric predictive inference (NPI) for exposure assessment. NPI is a distribution‐free method relying only on Hill's assumption . Effectively, is a postdata exchangeability assumption, which is a natural starting point for nonparametric statistics. For further discussion we refer to works by Hill and Coolen. We illustrate how NPI can be implemented to produce predictions for an individual's exposure based on consumption, body weight, and concentration data. NPI has the advantage that we do not have to assume a distribution to implement it. There may, however, be information available to suggest a distribution for a random quantity. Therefore, we present an NPI‐Bayes hybrid method where this information can be taken into account by using Bayesian methods while using NPI for the other random quantities in the model.