Patent Application
20140188495
1. Field of the Invention
The invention relates to a method for assessing and managing health risk of heavy metal pollution.
2. Description of the Related Art
In recent years, more and more heavy metal pollutants are discharged and accumulated in the ecosystem, and accidents of health damage and mass incident caused by heavy metal pollutants occur frequently. Thus, risk assessment and management of heavy metals have been a focus of environmental protection. Extensive studies on the risk assessment and management have been conducted, most of which are focused on one or several pollutants, a single environmental media, or a certain exposure way. However, these studies neglect characteristics of heavy metals, that is, multi-sources, multi-environmental media, multi-exposure routes, and multi-receptors, so that these kinds of risk assessment do not represent a panorama of the potential health risk in a certain population. Differences in risk degrees of different pollutants, and key exposure ways of pollutants are not made clear, so that the management cannot be conducted in the whole process of the health risk.
Furthermore, health damages caused by most of the heavy metal pollutants are chronic and not easily aware; but once health damages appeared, public unrest and dissatisfaction were accompanied, bringing up social contradictions and mass incidents. However, current studies seldom take into consideration of the public perception of heavy metal pollutants. A most prominent problem is that the public perception analysis is separated from the health risk analysis. Take the conventional four steps of health risk assessment in USA as an example, results based on single risk analysis are not effectively applied in the risk management or acceptable by the public; whereas the studies on signal risk perception only represents the public physiological state but does not identify the boundary of risk management because of absence of objective risk data. Therefore, a method capable of combining the risk assessment together with the risk perception and the acceptable risk level from the potential exposure population to achieve a substantive risk management of heavy metal pollution is desired.
In view of the above-described problems, it is one objective of the invention to provide a method for assessing and managing health risk of heavy metal pollution by which the health risk is panoramically analyzed from multi-sources, multi-environmental media, multi-exposure routes, and multi-receptors, the method integrates the risk assessment, the public risk perception, public acceptable risk level, and risk management together to establish a comprehensive risk management.
Principle of the method: system theory for risk analysis to study the whole process of health risk caused by heavy metal pollutants is employed; the characteristics of health risk, that is, multi-sources, multi-environmental media, multi-exposure routes, and multi-receptors, and control demands of the health risk are all considered for development of a method for assessing and managing health risk of heavy metal pollution; the method comprises: a risk assessment, a risk perception analysis, and a risk management, which is also called 4M3R method.
To achieve the above objective, in accordance with one embodiment of the invention, there is provided a method for assessing and managing health risk of heavy metal pollution. The method comprises the steps as follows:
Risk=CDI×SF Formula 1
Advantages of the invention are as follows:
The invention is described hereinbelow with reference to the accompanying drawings, in which:
To further illustrate the invention, experiments detailing a method for assessing and managing health risk of heavy metal pollution are described below. It should be noted that the following examples are intended to describe and not to limit the invention.
A method for assessing and managing health risk of heavy metal pollution was conducted as follows:
1) Investigation and analysis of environmental pollution: a large lead-zinc mine and a vicinage thereof was selected as a study area; a field investigation was conducted, wastes discharged from processes of ore production and transportation were identified as main risk sources, and residents living in the vicinage were identified as a main potential exposure population. Environmental samples comprising the drinking water, atmosphere, indoor air, soil, and food were collected, and concentrations of heavy metals in multiple environmental media were analyzed. A total of 13 heavy metals comprising As, Pb, Cr, an Zn were detected, in which, As was serious polluting, having 60.7 mg/kg of an average concentration in the soil and 9.9×10−3 mg/m3 of a concentration in the air.
2) Population exposure analysis: a population exposure investigation was conducted among 120 residents to know about the exposure parameters of the native people, these exposure parameters comprised: an amount of the drinking water, diet structure, and activity. Exposure ways of the residents comprised: drinking water intake, air intake, dermal exposure via the water and the soil, soil and food intake by mouth. Population exposure doses through different ways were estimated by applying an exposure analysis model disclosed by the US E EPA.
3) Risk assessment and representation: slop factors (SF) of heavy metals, and reference doses were referred from the IRIS database of US EPA. Cancer risk was calculated in compliance with formula 1, and non-cancer risk was calculated in compliance with formula 2 (results are shown in Table 1). Monte Carlo method was employed to conduct sampling calculation to acquire probability distribution of health risk values and contribution rates of different exposure ways.
4) Risk perception and estimate of acceptable level of risk: a questionnaire on public risk perception (shown in Table 2) was designed by employing a psychometric paradigm. The questionnaire was conducted in a form of interview among 240 samples. Public perceptions of health risk of heavy metals were analyzed, and results of acceptable level of risk were represented as a cumulative curve (as shown in
5) Identification of an overall boundary of risk management: for non-cancer risk, 6 heavy metals, i. e., As, Pb, Be, Cd, Sb, and Hg, had a hazard quotient larger than 1, which meant that risk values of these non-cancer risk were unacceptable by the public. For cancer risk, results of the population health risk assessment and public acceptable level of risk were compared, as shown in
6) Identification of priority pollutants: pollutants of cancer risk having a higher risk level than the public acceptable level, and pollutants of non-cancer risk having a higher value than the reference dose are indentified as priority pollutants. Thus, As, Pb, Be, Cd, Sb, and Hg were identified as priority pollutants in the lead zinc mine.
7) Identification a key population and a key managing point: according to risk assessment results of different regions and different population, residents in the vicinage of the lead zinc mine were identified as a key population. From the panorama analysis of population health risk and investigation of population exposure, air intake turned out to be the key exposure way, and 99% above cancer risk of heavy metal pollutants were through air intake. For the non-cancer risk, for example, the non-risk caused by lead, risk analysis was shown in
While particular embodiments of the invention have been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made without departing from the invention in its broader aspects, and therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of the invention.
