Reviews of Environmental Contamination and Toxicology

Radiation “refers to a physical phenomenon in which energy travels through space or matter” (Radomyski et el. 1994). Irradiation, as used in food science, is the application of this energy to a specific material, such as food product, with the purpose of increasing storage stability through reduction of microorganisms, elimination of parasites or insects, or blockage of enzyme activity. Irradiation may also used to reduce the risk of foodborne illness. For preservation of foods, the type of radiation applied is referred to as ionizing radiation because it produces electrically charged ions as the energy interacts with target molecules.

The health risks posed by waste products and by the accumulation of certain metals, including cadmium, are of great concern to health agencies and researchers. Cadmium, an element identified in 1817 (Schwarz 1974), is present in nature in low concentrations and is normally bound to Zn, Pb, or Cu. High levels of Cd are associated with sources of industrial emission (Linder 1985; National Research Council 1989), and very steep increases in contamination by this metal have been documented during the 1980s and 1990s (FAO-WHO 1986; Robards and Worsfold 1991; Seiler and Sigel 1988). The extensive use of Cd in industry has lead to widespread contamination, which has mid- and long-term physiopathological effects on the human body.

Ecotoxicological risk assessment provides a measure for adverse ecological effects of chemicals as a function of their concentration in the environment. The risk is commonly expressed as the ratio between the predicted environmental concentration (PEC) and the predicted no-effect concentration (PNEC) (Norton et al. 1992; Van Leeuwen and Hermens 1995). Another approach is to use statistical distributions for PECs and PNECs and to derive maximum acceptable concentrations from the risk associated with the probability of PEC being greater than PNEC. This approach has gone under the name of “distribution-based extrapolation methodology” (Aldenberg and Slob 1993; Forbes and Forbes 1993; Kooijman 1987; Okkerman et al. 1993; Smith and Cairns 1993; Van Straalen and Denneman 1989; Wagner and Løkke 1991.)

Organophosphate (OPs) and organocarbamate (OCs) esters are widely used pesticides. Their inhibition of cholinesterases (ChEs) is a major source of their toxicity. The need for detecting exposure to OPs and OCs has resulted in continuing interest in assaying for ChEs. This paper discusses assay techniques, their usefulness as indicators of exposure, and the problem of detecting adverse effects (Weiss 1990; Wilson et al. 1992a).

The history of agricultural harvesters being clinically poisoned from working in a field following a “recent” organophosphate (OP) insecticide application dates back to their earliest use circa 1950. Initially, the documentation was sporadic case reports (Abrams and Leonard 1950; Ingram 1951; Quinby and Lemmon 1958; Milby et al. 1964). Summaries began to be published beginning in 1974 (Milby et al. 1974; Spear et al. 1975; NIOSH 1976; Gunther et al. 1977; Popendorf and Leffingwell 1982; and Honeycutt et al. 1985).