Health risk assessment of an industrial site contaminated with polycyclic aromatic hydrocarbons using CalTOX, an environmental fate/exposure model.

This paper presents the results of a risk assessment study made using CalTOX, a multimedia, multiple pathway risk assessment model. The case study is based on the Polycyclic Aromatic Hydrocarbon (PAH) soil contamination resulting from the activities of a natural gas power station over a period of 70 years. It describes model characteristics and input parameters such as physico-chemical properties, landscape description, and human exposure factors. Model simulations and risk estimations corresponding to different remedial scenarios in an industrial zone are also presented. These estimations were based on soil contamination by 16 PAHs in the root-zone and vadose-zone layer. Results show that adult exposure (workers) to contaminated soil will lead to a potential health risk of carcinogenic effects, and to no potential risk of non-carcinogenic effects. On the other hand, the addition of 10 cm of clean soil over the contaminated soil (mitigated scenario) decreases the lifetime cancer risk to an acceptable level. The sensitivity analysis showed that the half-life of benzo[a]pyrene in the root-zone soil is the most sensitive parameter and that it contributes significantly to the variability of the cancer risk estimation. In addition, the cancer risk level of the workers exposed to this substance, as estimated by CalTOX (point estimate) in the mitigated and unmitigated scenario, corresponds approximately to the 95th percentile value obtained by means of Monte-Carlo simulations. Finally, CalTOX has proven to be a valuable tool to predict and elaborate scenarios for the risk management of sites contaminated as a result of industrial activities.

Acute and delayed emesis after cisplatin-based regimen: description and prevention.

Lorazepam, dexamethasone and high-dose metoclopramide were given to 54 patients to prevent emesis induced by cisplatin (50-120 mg/m2) on day 1, while prochlorperazine and dexamethasone were administered on days 2 and 3 for control of delayed emesis. Nausea and emesis were recorded from day 1 to day 8. This combination was well tolerated. Prevention on day 1 was complete for 72% of patients and satisfactory (less than or equal to 2 emeses on day 1) in 85%. From days 2 to 8, no emesis, less than or equal to 2 and greater than 2 episodes occurred in 70, 11 and 19%, respectively. Overall control (days 1-8) was complete in 55.5% and satisfactory (less than or equal to 2 emeses on day 1 and/or less than or equal to 2 emeses from days 2 to 8) in 74%. Delayed emesis started on days 2-5. Mean duration was 2.6 days. Delayed nausea or emesis were more frequent when emesis occurred on day 1. Based on data previously reported and on these observations, better ways to prevent delayed events are discussed. Further trials must record systematically delayed side effects.

Gentamicin: use of a programmable calculator to determine dosages from pharmacokinetic data for individual patients.

Gentamicin, an antibiotic frequently used in the treatment of gram-negative infections, has a narrow therapeutic index, so the correct prediction of its serum concentrations is important. Recent studies have emphasized the dubious accuracy of commonly used formulas, and computer programs that provide pharmacokinetic data for individual patients from multiple blood samples have helped to adjust dosages but are expensive. This study tested the applicability of a method using only two blood samples and a programmable calculator to estimate pharmacokinetic parameters for individual patients and adjust dosages to aim at peak and trough serum levels of 6 and 1 micrograms/ml respectively. In the 48 patients with normal renal function this method produced peak serum concentrations of gentamicin within 1 microgram/ml of the desired level in 22 (46%) and therapeutic peak concentrations (between 4 and 10 micrograms/ml) in all the patients. In 10 patients with renal failure it produced peak serum concentrations within 1 microgram/ml of the desired value in 4 and therapeutic serum concentrations in 7. Two patients had peak concentrations below 4 micrograms/ml and one had a peak concentration above 10 micrograms/ml. Two of the three patients whose serum levels were outside the therapeutic range had unstable renal insufficiency. Thus, patients with renal insufficiency need continued monitoring of the serum level of gentamicin, particularly when their renal function is changing.