Abandoned Metal Mines Research Articles

The Effect of Exposure Factors on the Concentration of Heavy Metals in Residents Near Abandoned Metal Mines

This study assessed the factors that have an influence on the residents exposed to heavy metals, and we utilized the findings to establish the proper management of abandoned metal mines in the future. For a total of 258 residents who lived close to abandoned mines in Gangwon-province and Gyeonggi-province, the exposure factors and biomarkers in their blood and urine were comparatively analyzed via multiple regression analysis. The blood levels of lead and mercury and the cadmium levels in urine were found to be higher in the study group than that in the average Korean. For the blood levels of heavy metals according to each exposure factor, all of them were found to be significantly higher in both of the group residing for a longer period of time and the group living closer to the source of pollutants. Multiple regression analysis disclosed that all the heavy metals, except lead, in their blood were significantly reduced in proportion to the increased distance of inhabitancy from the mines. Their other biomarkers were within the normal ranges. We found that the distance between the residential village and the mines was a factor that affects the blood level of heavy metals in the villagers. This finding could be an important factor when developing a management model for the areas that surround abandoned metal mines. (ED note: I much like this important study.).

Health Risk Assessment for Residents of Vicinity of Abandoned Mines in Gyeongsangbuk-do, Korea

PP-31-140 Background/Aims: The objective of this study was to evaluate the health risks for residents living at the vicinity of abandoned metal mines in Gyeongsangbuk-do, Korea. The abandoned mine tailings are remnants from an earlier flotation mill and mining operation that was in business from the early 1930 until 1970. Methods: The soil, stream water, drinking water, and crops in and around 2 abandoned mine areas, Woogok and Tohyun, and 2 control areas located in Gyeongsangbuk-do were analyzed for levels of Cd, Pb, Cu, As, and Hg. Potential chronic health effects were evaluated by medical examination. Blood and urine samples were collected for Pb, Cd, and As concentration determinations. Results: Some samples of soil and stream exceeded the Korean standard for soil contamination in farmland and the Korean standard of water contamination in streams, respectively. The amounts of oral intake of heavy metals were less than the acceptable daily intake level recommended by World Health Organization. Urine arsenic levels of the residents in the vicinity of the both abandoned mine sites (geometric mean: 10.07 μg/g Cr, 13.44 μg/g Cr) were significantly higher than that of the residents in the control areas (geometric mean: 8.19 μg/g Cr, 8.73 μg/g Cr). There were no significant differences between the mining and control areas in terms of blood pressure, Hb, BUN, creatinine, SGOT, SGPT, blood sugar, β2-microglobulin, N-acetyl-β-glucosaminidase, bone density, and the prevalence of potential chronic diseases. Conclusion: The results of the assessment suggested that the 2 abandoned mine sites do not pose an apparent health risk to nearby residents. Nevertheless, the elevated urine arsenic levels in the residents of the abandoned mine site suggested that it might be an important source of heavy metals contamination. Therefore, a nationwide evaluation program is needed to assess the potential health risks of residents living in the vicinity of abandoned mine sites.

Blood Lead Level of Residents Living Around 350 Abandoned Metal Mines in Korea

Blood Lead Level of Residents Living Around 350 Abandoned Metal Mines in Korea

Investigation and Risk Assessment of Heavy Metals Contamination around an Abandoned Metal Mine in Korea

Recently, heavy metals contamination of the agricultural soil and crops surrounding mining areas has been identified as one of the most serious environmental problems in South Korea. The Ministry of the Environment in Korea conducted a Preliminary National Environmental Health Survey (PNEHS) in abandoned metal mines in 2007. The priority for a subsequent detailed examination was ranked from the results of PNEHS. The studied mine which was ranked as being of the highest priority is located in the midwestern part of Korea and was operated from 1911 to 1985. In this study, the contamination levels of the heavy metals in the abandoned metal mine were investigated. From the results, the average daily dose (ADD), target hazard quotient (THQ) and target cancer risk of the heavy metals were evaluated. The concentration of arsenic (As) in all of the tailings from the mine was higher than its countermeasure standard of Korea. In particular, the highest concentration of As, 330 mg/kg, was up to 15 times higher than its countermeasure standard. The average concentration of As in agricultural soils was higher than the warning standard of Korea, and higher than its countermeasure standard at six sites. The average concentrations of the analyzed heavy metals in agricultural soil were below the warning standard, but concentrations of cadmium (Cd) and lead (Pb) at 4 sites were higher than its warning standard. The average concentration of As in surface water exceeded the warning standard of Korea. The value of the THQ of As for the tailings was higher than the health protection standard 1. The value of THQ of As for the farmlands was lower than the standard, while the hazard index (HI) of As was higher than the standard. The value of target cancer risk (TCR) of As, <TEX>$6.44{\times}10^{-4}$</TEX>, were higher than the health protection standard of a lifetime risk for TCR at <TEX>$1{\times}10^{-6}$</TEX>. This suggests that the residents around the metal mines are exposed to As pollution with a carcinogenic risk.

Screening risk assessment tools for assessing the environmental impact in an abandoned pyritic mine in Spain

This paper describes a new methodology for assessing site-specific environmental impact of contaminants. The proposed method integrates traditional risk assessment approaches with real and variable environmental characteristics at a local scale. Environmental impact on selected receptors was classified for each environmental compartment into 5 categories derived from the whole (chronic and acute) risk assessment using 8 risk levels. Risk levels were established according to three hazard quotients (HQs) which represented the ratio of exposure to acute and chronic toxicity values. This tool allowed integrating in only one impact category all the elements involved in the standard risk assessment. The methodology was applied to an abandoned metal mine in Spain, where high levels of As, Cd, Zn and Cu were detected. Risk affecting potential receptors such as aquatic and soil organisms and terrestrial vertebrates were assessed. Whole results showed that impact to the ecosystem is likely high and further investigation or remedial actions are necessary. Some proposals to refine the risk assessment for a more realistic diagnostic are included.

Ameliorants to immobilize Cd in rice paddy soils contaminated by abandoned metal mines in Korea

The cadmium (Cd) content of rice grain grown in metal-contaminated paddy soils near abandoned metal mines in South Korea was found to exceed safety guidelines (0.2 mg Cd kg⁻¹) set by the Korea Food and Drug Administration (KFDA). However, current remediation technologies for heavy metal-contaminated soils have limited application with respect to rice paddy soils. Laboratory and greenhouse experiments were conducted to assess the effects of amending contaminated rice paddy soils with zerovalent iron (ZVI), lime, humus, compost, and combinations of these compounds to immobilize Cd and inhibit Cd translocation to rice grain. Sequential extraction analysis revealed that treatment with the ameliorants induced a 50-90% decrease in the bioavailable Cd fractions when compared to the untreated control soil. When compared to the control, Cd uptake by rice was decreased in response to treatment with ZVI + humus (69%), lime (65%), ZVI + compost (61%), compost (46%), ZVI (42%), and humus (14%). In addition, ameliorants did not influence rice yield when compared to that of the control. Overall, the results of this study indicated that remediation technologies using ameliorants effectively reduce Cd bioavailability and uptake in contaminated rice paddy soils.

Removal of zinc by live, dead, and dried biomass of Fusarium spp. isolated from the abandoned-metal mine in South Korea and its perspective of producing nanocrystals

Bioremediation is an innovative and alternative technology to remove heavy metal pollutants from aqueous solution using biomass from various microorganisms like algae, fungi and bacteria. In this study biosorption of zinc onto live, dead and dried biomass of Fusarium spp. was investigated as a function of initial zinc(II) concentration, pH, temperature, agitation and inoculum volume. It was observed that dried, dead and live biomass efficiently removed zinc at 60 min at an initial pH of 6.0 ± 0.3. Temperature of 40 °C was optimum at agitation speed of 150 or 200 rpm. The initial metal concentration (10–320 mg L −1) significantly influenced the biosorption of the fungi. Overall, biosorption was high with 30–60% by dried, live and dead biomass. In addition to this, the potential of Fusarium spp. to produce zinc nanocrystals was determined by transmission electron microscopy, energy-dispersive spectroscopy, X-ray diffraction and fourier transform infrared spectroscopy, which showed that dead biomass was not significantly involved in production of zinc nanocrystals.

Inventory of aquatic contaminant flux arising from historical metal mining in England and Wales

The impact of discharges from abandoned metal and ironstone mines has been a much studied form of aquatic pollution in recent decades. Few attempts however, have been made to accurately determine the overall contaminant mass flux arising from abandoned mine sites at scales above catchment level. Such assessments are critical to determine the significance of former mining to national, regional and ultimately global trace metal flux. This paper presents the most comprehensive national survey to date across England and Wales of the total pollution burden discharged at source from abandoned non-coal mine sites. 338 discharges have been identified (from 4923 known abandoned metal mines) and while concurrent flow and contaminant concentration records are only available for around 30% of these, significant quantities of metals (and As) have been quantified to be discharged. A minimum of 193 tonnes of Zn, 18.5 tonnes of Pb, 0.64 tonnes Cd, 19.1 tonnes of Cu, 551 tonnes Fe, 72 tonnes Mn and 5.1 tonnes As are released in water discharges from abandoned non-coal mines to the surface water environment of England and Wales each year. Precautionary extrapolation of mass fluxes based on the frequency distribution of measured concentration and flow data, for discharges with absent data, suggests that the actual total mass flux for these contaminants could be up to 41% higher. The mass flux of Pb released from mines exceeds that of all currently permitted discharges (e.g. active industrial sites and wastewater treatment works) to surface waters across England and Wales, while those of As, Cd and Zn are of a similar magnitude. These data put into context the enduring legacy of historic mining on the water environment, highlighting its significance relative to more highly regulated polluting sites. Comparison of the figures with estimates of global trace metal flux suggests that the national total identified here is significant on a global scale.

일부 폐금속광산 지역 거주 여성의 요중 비소와 8-hydroxydeoxyguanosine 농도 사이의 관련성

본 연구는 비소에 대한 만성노출이 의심되는 일부 폐금속광산 주변 지역 주민 중 여성들을 대상으로 요중 비소 농도와 산화적 유전자 손상지표인 요중 8-hydroxydeoxyguanosine (8-OHdG) 농도와의 관련성을 평가하기 위해 시행되었다. 충청북도에 위치한 두 폐금속광산 지역 주민 중 여성 165명을 대상으로 요중 비소농도와 요중 8-OHdG의 농도를 측정하고 SPSS 12.0 통계프로그램을 이용하여 분석하였다. 조사 대상자들의 요중 비소농도는 기하평균이 <TEX>$5.65\;{\mu}g/g$</TEX> creatinine으로 나타났으며 요중 비소와 8-OHdG 농도와의 관련성 분석에서는 상관계수 0.399 (p<0.001)의 유의한 상관성을 보였다. 이러한 관련성은 비소노출 농도가 낮은 경우가 노출농도가 높은 경우에 비해 상대적으로 높은 것으로 나타났다. 본 연구의 결과는 요중 8-OHdG 농도가 저농도의 비소에 만성적으로 노출된 여성에서 산화적 유전자 손상을 평가하는 좋은 지표가 될 수 있음을 시사한다. This study examines the relationship between urinary arsenic concentration and urinary 8-hydroxydeoxyguanosine (8-OHdG) concentrations, an index of oxidative DNA damage, among women who live near abandoned metal mines. The sample consisted of 165 residents living near two abandoned metal mines located in Chungbuk Province. Demographic characteristics as well as environmental factors relevant to arsenic exposure were collected through interviews, and urinary arsenic concentrations and urinary 8-OHdG concentrations of the research subjects were measured. The collected data were subsequently analyzed using the statistics program SPSS 12.0. The geometric average of urinary arsenic concentrations among the research subjects was <TEX>$5.65\;{\mu}g/g$</TEX> creatinine. In a correlation analysis between urinary arsenic and 8-OHdG concentrations, the correlation coefficient was significant (p<0.001) at 0.399. This study suggests that urinary 8-OHdG concentrations may be a DNA damage marker for chronic arsenic exposure in women.

Blood and Urinary Cadmium Concentration of Residents around Abandoned Metal Mines in Busan and Gyeongsangnam-do

Blood and Urinary Cadmium Concentration of Residents around Abandoned Metal Mines in Busan and Gyeongsangnam-do

Leachability of Arsenic and Heavy Metals from Mine Tailings of Abandoned Metal Mines

Mine tailings from an abandoned metal mine in Korea contained high concentrations of arsenic (As) and heavy metals [e.g., As: 67,336, Fe: 137,180, Cu: 764, Pb: 3,572, and Zn: 12,420 (mg/kg)]. US EPA method 6010 was an effective method for analyzing total arsenic and heavy metals concentrations. Arsenic in the mine tailings showed a high residual fraction of 89% by a sequential extraction. In Toxicity Characteristic Leaching Procedure (TCLP) and Korean Standard Leaching Test (KSLT), leaching concentrations of arsenic and heavy metals were very low [e.g., As (mg/L): 0.4 for TCLP and 0.2 for KSLT; cf. As criteria (mg/L): 5.0 for TCLP and 1.5 for KSLT].

Abandoned Metal Mine Stability Risk Evaluation

The abandoned mine legacy is critical in many countries around the world, where mine cave-ins and surface subsidence disruptions are perpetual risks that can affect the population, infrastructure, historical legacies, land use, and the environment. This article establishes abandoned metal mine failure risk evaluation approaches and quantification techniques based on the Canadian mining experience. These utilize clear geomechanics considerations such as failure mechanisms, which are dependent on well-defined rock mass parameters. Quantified risk is computed using probability of failure (probabilistics using limit-equilibrium factors of safety or applicable numerical modeling factor of safety quantifications) times a consequence impact value. Semi-quantified risk can be based on failure-case-study-based empirical data used in calculating probability of failure, and personal experience can provide qualified hazard and impact consequence assessments. The article provides outlines for land use and selection of remediation measures based on risk.

Use of Ochre from an Abandoned Metal Mine in the South East of Ireland for Phosphorus Sequestration from Dairy Dirty Water

Ochre found at coal mine drainage sites in the United Kingdom shows a high phosphorus (P) retention capacity with little mobilization of metals. This indicates that ochre has the potential to adsorb P from agricultural wastewaters for possible use as a fertilizer. Little research has focused on the ability of metal mine ochre to sequester P in an environmentally sustainable way. Untreated acid mine drainage from an abandoned copper-sulfur mine in the Avoca-Avonmore catchment in the south east of Ireland results in extensive low-value ochre deposition. In this study, P-amended water (50 mL) was mixed with this ochre (2.5 g) in batch experiments, and a maximum P adsorption capacity, calculated from the Langmuir equation, of between 16 and 21 g P kg(-1) was calculated. However, mobilization of heavy metals from Avoca ochre in distilled, surface, and dirty water batch experiments was observed. This mobilization may inhibit ochre's use in P removal from wastewaters.

Relationship between plant biodiversity and heavy metal bioavailability in grasslands overlying an abandoned mine

Abandoned metal mines in the Sierra de Guadarrama, Madrid, Spain, are often located in areas of high ecological value. This is true of an abandoned barium mine situated in the heart of a bird sanctuary. Today the area sustains grasslands, interspersed with oakwood formations of Quercus ilex and heywood scrub (Retama sphaerocarpa L.), used by cattle, sheep and wild animals. Our study was designed to establish a relationship between the plant biodiversity of these grasslands and the bioavailability of heavy metals in the topsoil layer of this abandoned mine. We conducted soil chemical analyses and performed a greenhouse evaluation of the effects of different soil heavy metal concentrations on biodiversity. The greenhouse bioassays were run for 6 months using soil samples obtained from the mine polluted with heavy metals (Cu, Zn, Pb and Cd) and from a control pasture. Soil heavy metal and Na concentrations, along with the pH, had intense negative effects on plant biodiversity, as determined through changes in the Shannon index and species richness. Numbers of grasses, legumes, and composites were reduced, whilst other species (including ruderals) were affected to a lesser extent. Zinc had the greatest effect on biodiversity, followed by Cd and Cu. When we compared the sensitivity of the biodiversity indicators to the different metal content variables, pseudototal metal concentrations determined by X-ray fluorescence (XRF) were the most sensitive, followed by available and soluble metal contents. Worse correlations between biodiversity variables and metal variables were shown by pseudototal contents obtained by plasma emission spectroscopy (ICP-OES). Our results highlight the importance of using as many different indicators as possible to reliably assess the response shown by plants to heavy metal soil pollution.

Investigation on health effects of an abandoned metal mine.

To investigate potential health risks associated with exposure to metals from an abandoned metal mine, the authors studied people living near an abandoned mine (n=102) and control groups (n=149). Levels of cadmium, copper, arsenic, lead, and zinc were measured in the air, soil, drinking water, and agricultural products. To assess individual exposure, biomarkers of each metal in blood and urine were measured. β2-microglobulin, α1-microglobulin, and N-acetyl-beta-glucosaminidase and bone mineral density were measured. Surface soil in the study area showed 2-10 times higher levels of metals compared to that of the control area. Metal concentrations in the groundwater and air did not show any notable differences between groups. Mean concentrations of cadmium and copper in rice and barley from the study area were significantly higher than those of the control area (p<0.05). Geometric means of blood and urine cadmium in the study area were 2.9 µg/L and 1.5 µg/g Cr, respectively, significantly higher than those in the control area (p<0.05). There were no differences in the levels of urinary markers of early kidney dysfunction and bone mineral density. The authors conclude that the residents near the abandoned mine were exposed to higher levels of metals through various routes.

Preliminary Results: Release of Metals from Acid-Mine Drainage Contaminated Streambed Sediments under Anaerobic Conditions

Many miles of streams in the western U.S are contaminated with acidmine drainage (AMD) from abandoned metal mines. Treatment of these streams may include removal of the existing sediments, with subsequent burial (e.g. in a repository). Burial of previously aerobic sediments may result in release of metals through multiple processes, including reductive-dissolution of metal oxyhydroxides, with concurrent release of previously sorbed metals. This paper discusses preliminary results from a laboratory study examining the release of Cd, Cu, Fe, Mn, and Zn from aerobic streambed sediments collected from an AMDimpacted stream (North Fork Clear Creek, CO). The pH, Eh, and metal release were monitored over twenty-eight days in an anaerobic chamber from sediment slurries prepared using filtered stream water. Additionally, the effect of sediment size was examined by using two size fractions: 2 mm to 63 μm and less than 63 μm. Dissolved Cd, Cu, Fe, and Mn were released and re-sequestered over time from both sediment size fractions. Dissolved Zn, however, demonstrated a continual decrease in concentration over time, relative to the concentration present in the stream water used to prepare the slurries. Releases of Cd, Cu, Fe, and Mn varied for each of the size fractions over time. In the case of Cd and Cu, no further release was observed in either size fraction after one week. Releases of Fe and Mn declined after the first week in the smaller size fraction and after the second week in the larger size fraction. Because of the presence of SO4 in the stream water, it is hypothesized that the metals were re-sequestered as sulfide precipitates. Future studies will include replication, measurement of sulfur species, and the use of surface chemical techniques to examine the solids for the presence of metal oxides and sulfides. Additional

Contamination by Cd, Cu, Pb, and Zn in mine wastes from abandoned metal mines classified as mineralization types in Korea

The objective of this study was to investigate heavy metal contamination and geochemical characteristics of mine wastes, including tailings, from 38 abandoned mines classified as five mineralization types. Mine waste materials including tailings and soils were sampled from the mines and the physical and chemical characteristics of the samples were analyzed. The particle size of tailings was in the range of 10-100 microm. The pH of the waste covered a wide range, from 1.73 to 8.11, and was influenced by associated minerals and elevated levels of Cd, Cu, Pb, and Zn, extracted by a Korean Standard Method (digestion with 0.1 mol L(-1) HCl), which were found in the wastes. Half of the samples contained heavy metals at levels above those stipulated by the Soil Environmental Conservation Act (SECA) in Korea. In addition, extremely high concentrations of the metals were also found in mine wastes extracted by aqua regia, especially those from mines associated with sulfide minerals. Thus, it can be expected that trace elements in mine wastes may be dispersed both downstream and downslope through water and wind. Eventually they may pose a potential health risk to residents in the vicinity of the mine. It is necessary to control mine wastes by using a proper method for their reclamation, such as neutralization of the mine wastes using a fine-grained limestone.

Human Risk Assessment for Heavy Metals and as Contamination in the Abandoned Metal Mine Areas, Korea

Cleanup goals for the contaminated sites are established on the basis of risk assessments and rely on the estimated toxicity of the chemicals of concern (COC). Toxicity estimates are based on bioavailability causing risk of adverse health effects on humans. In this study, bioavailability of As, Cu, Pb and Zn in soil was determined by SBET (Simple Bioavailability Extraction Test), and chemical analysis for groundwater and stream water collected from the abandoned mine areas (Dukeum, Dongil, Dongjung, Myungbong and Songchun mine areas) was conducted. High values of cancer risk for As (1.16x10(-5)) were detected through soil ingestion pathways in the Songchun mine area and assessed through water exposure pathways in the all mines except Dukeum. The hazard index value for As in the Songchun mine area (3.625) exceeded 1.0. The results indicated that the ingestion of As-contaminated soil and water by local inhabitants can pose a potential health threat in these mine areas.

Investigation and risk assessment modeling of As and other heavy metals contamination around five abandoned metal mines in Korea

Tailings, agricultural soils, vegetables and groundwater samples were collected from abandoned metal mines (Duckum, Dongil, Dongjung, Myoungbong and Songchun mines) in Korea. Total concentrations of arsenic (As) and heavy metals (Cd, Cu, Pb and Zn) were analyzed to investigate the contamination level. Several digestion methods (Toxicity characteristics leaching procedure (TCLP), synthetic precipitation leaching procedure (SPLP), 0.1 N/1 N HCl) and sequential extraction analysis for mine tailings were conducted to examine the potential leachability of As and heavy metals from the tailings. The order of urgent remediation for the studied mines based on the risk assessment and remedial goals was suggested. The Songchun mine tailings were most severely contaminated by As and heavy metals. Total concentrations of As and Pb in the tailings were 38,600-58,700 mg/kg (av. 47,400 mg/kg) and 11,800-16,800 mg/kg (av. 14,600 mg/kg), respectively. Agricultural soils having high As concentrations were found at the all mines. Average concentrations of Cd in the vegetables exceeded the normal value at all mines areas, while As only at the Dongjung, Myoungbong, and Songchun mine area. One groundwater sample each from the Dongil and Myoungbong mines, and 4 groundwater samples from the Songchun mine had values above 10 mug/L of As concentration. The TCLP method revealed that only Pb in the Songchun tailings, 6.49 mg/L, exceeded the regulatory level (5 mg/L). Employing the 1-N HCl digestion method, the concentration of As in the Songchun mine tailings, 4,250 mg/kg, was up to 3,000 times higher than its Korean countermeasure standard. Results from the sequential extraction of As in the tailings showed that the easily releasable fraction in the Myoungbong and Songchun mine tailings was more than 30% and the residual fraction was less than 40%. Based on results showing the exposure health risk employing the hazard quotient and cancer risk of As, Cd and Zn, the Dongil mine needs the most urgent remedial action. The concentration reduction factor (CRF) of As in both soil and groundwater follows the order: Songchun>Dongjung>Dongil>Myoungbong>Duckum mine.

Peripheral Arterial Disease and Metals in Urine and Blood

Navas-Acien et al. (2005) recently analyzed the data from the 1999–2000 National Health and Nutrition Examination Survey (NHANES). They suggested that blood lead and blood and urinary cadmium, at levels well below safety standards, were associated with an increased prevalence of peripheral arterial disease (PAD) and that cadmium might partly mediate the detrimental arterial effects of smoking. The authors recognized that their findings needed confirmation and support from mechanistic studies. In line with their suggestion, we analyzed data from 428 participants in the Flemish Study on Environment, Genes, and Health Outcomes (Staessen et al. 1994). As described by Navas-Acien et al. (2005), we included only subjects who were at least 40 years of age and we defined PAD as an ankle brachial index of > 0.9 in at least one leg. Blood lead and blood and urinary cadmium were measured by atomic absorption spectrometry. The geometric mean concentrations were 0.43 nmol/L [5th–95th percentile interval (PI), 0.19–1.03] for blood lead and 11.6 nmol/L (PI, 3.6–31.1) for blood cadmium. The urinary cadmium excretion averaged 11.6 nmol/24 hr (PI, 3.8–35.5). We adjusted for demographic and cardiovascular risk factors. For blood lead and cadmium, the odds ratios of PAD comparing quartiles 2–4 with the lowest quartile were in line with those of Navas-Acien et al. (2005). However, for the 24-hr urinary cadmium excretion the p-value for trend was only 0.72. Urinary cadmium is a more precise biomarker of exposure than blood cadmium, because urinary cadmium reflects lifetime exposure and blood cadmium reflects more recent exposure. Navas-Acien et al. (2005) measured only metal concentrations in spot urine samples (Navas-Acien et al. 2005), whereas we measured the 24-hr excretion of cadmium. We could not demonstrate any relation between cardiovascular disease or the incidence of hypertension in relation to environmental exposure to lead and cadmium (Staessen et al. 2000). We therefore concur with their conclusion that the role of cadmium in the pathogenesis of atherosclerosis needs further research. However, not only are mechanistic studies required but also population studies, for example, that relate pulse wave velocity to biomarkers of cadmium exposure. We currently have similar experiments in progress.