Human exposure to heavy metals in the vicinity of Portuguese solid waste incinerators--Part 2: biomonitoring of lead in maternal and umbilical cord blood.

As part of environmental health surveillance programs related to solid waste incinerators located near Lisbon and on Madeira Island, human biomonitoring projects have been implemented in Portugal, some of them focused on cross-sectional surveys of heavy metals in blood. One of the general aims of these programs is to provide Portuguese data on the extent and pattern of human exposure to the pollutants potentially released in the stack gases from the incinerators, namely heavy metals. The present investigation reports information specifically on blood lead levels of newborn-mother pairs living in the vicinity of the incinerators under study, as well as of statistically similar participants living outside the exposed area. For Lisbon, lead levels determined at the baseline period (T0), as well as three subsequent evaluations of potential specific impacts of the incinerator (T1, T2 and T3) are described in order to investigate spatial and temporal trends of human exposure to lead. Available data for Madeira, namely lead levels in blood from the study population before the incinerator started operation, is also described. For Lisbon, analyses showed a statistically significant decrease of lead concentrations in maternal (p<0.001) and umbilical cord blood (p<0.001) during the whole monitoring period. Practically "overt" transplacental exposure to lead was observed only in the Lisbon biomonitoring project and for some cross-sectional surveys. Baseline levels for Madeira were the lowest found in all observations already performed in both programs (maternal and umbilical cord mean lead levels of 0.4 microg/dl and 0.3 microg/dl, respectively). No statistical associations have been found between lead levels in blood and age neither for global populations from Lisbon and Madeira nor for specific groups included in the different observational periods.

Human exposure to heavy metals in the vicinity of Portuguese solid waste incinerators--Part 3: biomonitoring of Pb in blood of children under the age of 6 years.

As a part of environmental health surveillance programs related to Portuguese solid waste incinerators (SWI), two biomonitoring projects have been established to investigate additional exposure to lead in children under the age of 6 years living in the vicinity of those facilities. The above-mentioned programs, being the only ones in the country that integrate systematic observations on human exposure to heavy metals, have to provide systematic data from Portuguese regions on the extent and pattern of human exposure to heavy metals, namely to lead. The present paper is the third of a series of papers prepared to accomplish that objective in regards to lead exposure as evaluated by measuring lead levels in children under the age of 6 years. Altogether, 250 children from Lisbon and 247 from Madeira Island have already been involved in the investigation. The present study evaluates spatial and temporal trends of lead exposure, based on comparisons of children's blood lead levels, either stratified by living area (exposed and control groups), or by time of exposure (T0, the baseline time, and T1, after approximately 2 years of regular operation of the facilities). The results obtained correspond to a relatively reduced number of individuals. Possibly for this reason, they are not fully conclusive in relation to whether living in the vicinity of SWI represents an additional risk of higher exposure to lead. Time trends of lead exposure as evaluated by blood lead levels in children also do not show any clear pattern. These conclusions and the fact that altogether around 3% of children from the whole group have blood lead levels >or=10 microg/dl warrant further investigation in order to clarify the contribution of incinerator emissions to the levels of lead in children and to identify alternative sources for preventive purposes, taking into consideration the relevance of even low lead exposure from a public health perspective, mainly in relation to children.

Human exposure to heavy metals in the vicinity of Portuguese solid waste incinerators--Part 1: biomonitoring of Pb, Cd and Hg in blood of the general population.

Human exposure to heavy metals makes it necessary to monitor these elements in the human body if the objective is to relate heavy metal exposure to adverse health effects. In Portugal, biomonitoring projects on heavy metals are being carried out on people living in the vicinity of solid waste incinerators. The projects are being developed in the ambit of two environmental health surveillance programs related to solid waste incineration facilities, one near Lisbon and the other on Madeira Island, that have the main objective of guaranteeing the safeguard of public health in relation to the potential negative impact of incineration processes on human health. These programs are the only ones in the country that integrate a systematic observation of human exposure to heavy metals as determined by the respective body burden in several population groups. Therefore, they are the only ones that are currently able to provide systematic data from Portuguese regions on the extent and pattern of human exposure to this type of pollutants. The present paper is the first of a series of three prepared papers with the objective of presenting and discussing available data. It addresses exposure to lead, cadmium and mercury as determined by their levels in blood of general population adults. Results suggest the effectiveness of source control measures in relation to both incinerators under study, similarly to what has been concluded from previous studies addressing exposure to dioxins. They also show, in relation to the baseline situation, a general significant trend for reduction of exposure to all studied heavy metals. Individuals from Lisbon seem to have a significantly higher body burden of the studied metals than those living in Madeira and, in general, metal exposure in men is significantly higher than in women, with the most relevant exception being the case of higher mercury levels in women, at the baseline and for both communities. Compared with published reference values for similar conditions, blood levels of cadmium, lead, and mercury of the present investigation seem to be relatively higher, in median terms and for extreme values, mainly in the case of cadmium and mercury. In the case of lead the differences are not so marked.