[The precautionary principle: is it applicable to occupational medicine?]. / Il principio di precauzione: è applicabile in medicina del lavoro?

Precautionary Principle (PP) and its application to environmental and health policy appear in the 70's and from that time is introduced more and more frequently in different international treaties and conferences on environment and health. PP is a risk management policy applied to scientifically uncertain circumstances where it is necessary to act against a potentially harmful risk factor without waiting for more accurate information. When this situation takes place at the workplace, the risk management is an Employer's task. The employer can use different instruments, including the occupational physician's advise, to reach their target. After identification of possible health and safety risk factors and after characterisation of a non-admissible risk for worker's health, the Employer must chose which precautionary actions to take, also in function of economic, technical and judicial needs and restrictions. This action can be the application of measures of "prudent avoidance" through steps such as health surveillance, until more radical measures are taken by using P.P. The Occupational health specialist that is already operating of the work place with characterised and well known risk factors should introduce the instruments, in the health surveillance activities, that may detect possibly adverse effects related to risk factors characterised by scientific uncertainty. This is very important whenever the employers don't have the possibilities or are not sensitive enough to take other kinds of precautionary measures. Moreover, the occupational physician should play an active role also in the risk assessment phase by defining those chemicals or physical agents still characterized by scientific uncertainty.

[Evaluation of the neurotoxic and nephrotoxic effects following long-term exposure to metallic mercury in employed at a chlorine/sodium-hydroxide plant]. / Valutazione degli effetti neurotossici e nefrotossici conseguenti all'esposizione a lungo termine a mercurio metallico dei lavoratori addetti agli impianti Cloro-Soda.

OBJECTIVES: Within the frame work of a wide multicentre study, a sub-study was developed in order to explore the occurrence of early effects on the central nervous system, on the kidney and on the neuro-immune system in the workers of a chloro-alkali production plant exposed to metallic mercury at airborne concentration levels lower than 0.025 mg/m3 (TLV-TWA). They were compared to a control population of employees of the same huge petrochemical plant with different job that did not implicate exposure to mercury vapors. Specifically, the study aimed at revealing the occurrence of early effects on the central nervous system related with mercury exposure, as can be assessed through neurophysiological and neurobehavioral tests. METHODS: The excretion of urinary mercury was measured by atomic absorption spectrometry. The study of renal function was assessed by measurement of the urinary excretion of some high and low molecular weight protein markers (albumin, beta 2-microglobulin, retinol-binding protein, fibronectin, specific proximal tubule brush border antigens, N-acetyl-beta-D-glucosaminidase). The neurobehavioral status of the study subjects was assessed by means of several test parameters (Simple Reaction Time, Color Word Vigilance Test, Symbol Digit, Finger Tapping, Mood Scale of Kjellberg and Iwanowski, Subjective symptoms questionnaire (QSS), Luria Nebraska Motor Scale, Branches Alternate Movement Task and Tremometry). RESULTS: The values of urinary excretion averaged 12 +/- 8 micrograms Hg/g of creatinine for the exposed workers group (n = 38), while for the reference group (n = 34 cases) urinary excretion was statistically lower, averaging 4 +/- 6 micrograms Hg/g of creatinine. Neither the parameters selected for the assessment of renal functions, nor those chosen to probe the neurobehavioral status of the probands revealed statistically reliable differences between the group of exposed workers (length of exposure: range 1-34 years) and the control group. Nevertheless, some minor but still statistically reliable correlations were found between some neurobehavioral parameters and some demographic variables describing the whole group of tested workers, but not to the level of occupational exposure to mercury. CONCLUSIONS: The results of the study confirm the lack of toxic effects of clinical importance on the central nervous system and on the kidney for values of mercury urinary excretion lower than the suggested index of biological exposure (IBE) of 35 micrograms Hg/gram of creatinine.