Cancer risk near a polluted river in Finland

Association between oil spill clean-up work and thyroid cancer: Nine years of follow-up after the Hebei Spirit oil spill accident

In 2007, an unprecedented oil spill occurred in Taean, Korea. Although crude oil contains chemicals that could increase thyroid cancer risk, few studies have examined the long-term effects of oil exposure during clean-up and thyroid cancer incidence. We investigated the long-term thyroid cancer incidence among participants involved in clean-up work. 1798 participants engaged in at least two surveys since the baseline was tracked from 2008 to 2018. Participants reported the days they participated in oil clean-up works and cancer diagnoses. Cox proportional hazard models were used to estimate the hazard ratios between clean-up work duration and thyroid cancer. Over the 9-year follow-up, 30 thyroid cancer cases were diagnosed. A positive association was observed between clean-up duration and thyroid cancer risk. This effect was more pronounced among residents living <50 m from traffic roads. Our results indicate that crude oil clean-up work participation may increase the thyroid cancer risk.

Thyroid nodules coexisting with either cystic or solid breast nodules: a new clue for this association between nodules coming from ultrasonography

Background

Thyroid and breast nodules (BNs) are common, their prevalence varying based mainly on the population (including age, residence in area of different iodine availability) studied and methods used. The coincidence of thyroid and breast diseases remains controversial and the majority of the studies evaluate the association between breast cancer and thyroid disorders. Here we describe our experience of such association in a non-oncological series.

Methods

Between the years 2000 and 2005, 3,372 patients from outpatient clinics were referred for thyroid ultrasonography (US) at our University Hospital; concurrent breast US in the 1,896 women revealed the presence of BNs in 127. The 127 women were divided into two groups, based on the cystic or solid nature of the BN(s).

Results

In 84/127 (66.1%) the single or multiple BN was/were cystic (group 1), while in the remaining 43 (33.9%) the single or multiple BN was/were solid [group 2; 19/43 had one thyroid nodule (TN) and the remaining 24/43 had ≥2 TNs]. When BN were cystic the coexisting TN(s) was/were more likely to be concordant in localization (i.e., right/right or left/left localization) whereas, when the BN were solid, the coexisting thyroid nodule/nodules was/were more likely to be discordant. In women with cystic BNs (CBNs), TNs were more frequently multiple (64% of cases), whereas in cases with solid BNs (SBNs), the frequency of single and multiple TNs was approximately the same. In patients with TNs/CBNs, TNs tend to be subcentimetric and localized in the inferior pole of either thyroid lobe. In patients with TNs/SBNs, TNs tend to be larger and localized in the middle of either thyroid lobe.

Conclusions

In women with BNs associated with TNs, there are interesting differences concerning TNs when patients are stratified based on the cystic or solid nature of the BN.

Cancer and non-cancer excess mortality resulting from mixed exposure to polychlorinated biphenyls and polychlorinated dibenzofurans from contaminated rice oil: "Yusho"

PURPOSE

In 1968, rice oil contaminated with polychlorinated biphenyls and polychlorinated dibenzofurans caused a severe outbreak of food poisoning in Japan and was termed locally as "Yusho" (oil disease). In our previous study, we found that area-based standardized mortality ratios (SMRs) of some diseases were elevated shortly after the incident. This previous study, however, was unable to determine whether these elevated SMRs were a result of other area-specific factors. To overcome this limitation, we obtained mortality data from the 5 years before the incident and conducted an area-based study using vital statistics records dating from 1963 to 2002.

METHODS

The population of Nagasaki Prefecture was set as the reference population for calculating SMRs. We also included data on cause-specific mortality attributable to cancer and expanded the population to encompass two severely exposed areas where contaminated rice oil was distributed (namely Tamanoura and Naru). We also calculated SMRs in the remainder of the Shimo-Goto region, excluding the exposed area, which was used as a comparison area.

RESULTS

Even after considering the time trends in mortality before the incident, mortality due to diabetes mellitus and heart disease, as well as all-cause mortality, was found to be elevated shortly afterward. Additionally, mortalities due to uterine cancer in Tamanoura and leukemia were also elevated at 30-34 and 10-59 years after the event in both exposed areas, respectively. SMRs for leukemia in Tamanoura were as high as 3.0 (95% confidence interval 1.4-6.2) and 2.4 (1.2-4.8) 10-19 years later. In this period, SMRs for leukemia in the comparison area were not elevated.

CONCLUSIONS

Further epidemiological studies are needed regarding this rice-oil, "Yusho" outbreak, especially with regard to cancer and non-cancer mortality.

Development of a spatial stochastic multimedia exposure model to assess population exposure at a regional scale

Analyzing the relationship between the environment and health has become a major focus of public health efforts in France, as evidenced by the national action plans for health and the environment. These plans have identified the following two priorities: - identify and manage geographic areas where hotspot exposures are a potential risk to human health; and - reduce exposure inequalities. The aim of this study is to develop a spatial stochastic multimedia exposure model for detecting vulnerable populations and analyzing exposure determinants at a fine resolution and regional scale. A multimedia exposure model was developed by INERIS to assess the transfer of substances from the environment to humans through inhalation and ingestion pathways. The RESPIR project adds a spatial dimension by linking GIS (Geographic Information System) to the model. Tools are developed using modeling, spatial analysis and geostatistic methods to build and discretize interesting variables and indicators from different supports and resolutions on a 1-km(2) regular grid. We applied this model to the risk assessment of exposure to metals (cadmium, lead and nickel) using data from a region in France (Nord-Pas-de-Calais). The considered exposure pathways include the atmospheric contaminant inhalation and ingestion of soil, vegetation, meat, egg, milk, fish and drinking water. Exposure scenarios are defined for different reference groups (age, dietary properties, and the fraction of food produced locally). The two largest risks correspond to an ancient industrial site (Metaleurop) and the Lille agglomeration. In these areas, cadmium, vegetation ingestion and soil contamination are the principal determinants of the computed risk.

Risk of dying of cancer in the vicinity of multiple pollutant sources associated with the metal industry

BACKGROUND

Population exposure to emissions from multiple industrial sources, though little studied, is an aspect of great interest from an epidemiologic standpoint.

OBJECTIVES

To investigate whether risk of dying due to tumors of the digestive system in populations residing in the vicinity of Spanish metal production and processing installations increases with proximity to a greater number of industrial facilities.

METHODS

An ecologic study was designed to ascertain municipal mortality due to malignant tumors of the digestive system (oral cavity and pharynx, esophagus, stomach, pancreas, liver, gallbladder and colon-rectum) during the period 1994-2003, in Spanish regions with the presence of multiple industrial sources in the metal sector. Population exposure to pollution was estimated on the basis of distance from town of residence to pollution source. Using Poisson regression models, we analyzed: the increased risk of dying of cancer with proximity to a given number of sources; and excess mortality in the vicinity of specific industrial clusters.

RESULTS

The tumor responsible for the greatest number of regions with increased risk in both sexes was liver cancer (78% of the regions, being statistically significant in Valencia (p-value for trend (p trend)=0.001 in both sexes), Madrid (p trend=0.011 in women) and the Basque Country (p trend=0.002 in men)), followed by colorectal and pancreatic cancers (56% of the regions, being statistically significant in both sexes in Valencia (p trend=0.001) and Zaragoza (p trend=0.018) for colorectal cancer; and Valladolid (p trend=0.019 in men) and Barcelona (p trend=0.049 in women) for pancreatic cancer). Valencia was the province that displayed increased risk with the proximity to metal industries for all tumors studied, while the Basque Country was the Autonomous Region that registered a rising risk trend for liver, stomach and colorectal tumors with proximity (≤5 km) to a greater number of sources.

CONCLUSIONS

The results could support the hypothesis that mortality due to certain tumors of the digestive system increases with proximity (≤5 km) to a greater number of metal industry sources. Nevertheless, in this type of ecologic study, conclusions cannot be obtained in terms of cause and effect, nor can individual inferences be made from grouped data.

Feasibility and utility of mapping disease risk at the neighbourhood level within a Canadian public health unit: an ecological study

Background

We conducted spatial analyses to determine the geographic variation of cancer at the neighbourhood level (dissemination areas or DAs) within the area of a single Ontario public health unit, Wellington-Dufferin-Guelph, covering a population of 238,326 inhabitants. Cancer incidence data between 1999 and 2003 were obtained from the Ontario Cancer Registry and were geocoded down to the level of DA using the enhanced Postal Code Conversion File. The 2001 Census of Canada provided information on the size and age-sex structure of the population at the DA level, in addition to information about selected census covariates, such as average neighbourhood income.

Results

Age standardized incidence ratios for cancer and the prevalence of census covariates were calculated for each of 331 dissemination areas in Wellington-Dufferin-Guelph. The standardized incidence ratios (SIR) for cancer varied dramatically across the dissemination areas. However, application of the Moran's I statistic, a popular index of spatial autocorrelation, suggested significant spatial patterns for only two cancers, lung and prostate, both in males (p < 0.001 and p = 0.002, respectively). Employing Bayesian hierarchical models, areas in the urban core of the City of Guelph had significantly higher SIRs for male lung cancer than the remainder of Wellington-Dufferin-Guelph; and, neighbourhoods in the urban and surrounding rural areas of Orangeville exhibited significantly higher SIRs for prostate cancer. After adjustment for age and spatial dependence, average household income attenuated much of the spatial pattern of lung cancer, but not of prostate cancer.

Conclusion

This paper demonstrates the feasibility and utility of a systematic approach to identifying neighbourhoods, within the area served by a public health unit, that have significantly higher risks of cancer. This exploratory, ecologic study suggests several hypotheses for these spatial patterns that warrant further investigations. To the best of our knowledge, this is the first Canadian study published in the peer-reviewed literature estimating the risk of relatively rare public health outcomes at a very small areal level, namely dissemination areas.

Paradoxical increases in serum levels of highly chlorinated PCBs in aged women in clear contrast to robust decreases in dietary intakes from 1980 to 2003 in Japan

OBJECTIVE

Exposure to polychlorinated biphenyls (PCBs) is considered to have culminated between 1950 and 1970 in Japan, and exposure through diet, the major exposure route, has decreased significantly over the last 10 years. The primary goal of the present study was to investigate the long-term trends and congener profiles of serum and dietary levels of PCBs using historical samples.

METHODS

Using banked samples collected in 1980, 1995, and 2003 surveys, we determined the daily intakes and serum concentrations of 13 PCB congeners (#74, #99, #118, #138, #146, #153, #156, #163, #164, #170, #180, #182, and #187) in women.

RESULTS

The total daily PCB intake [ng/day, geometric mean (geometric standard deviation)] decreased significantly from 523 (2.5) in 1980 to 63 (3.2) in 2003. The serum total PCB level (ng/g lipid) in women <40 years of age decreased significantly from 185 (1.8) in 1980 to 68 (1.8) in 2003. In contrast, the level in women >50 years of age increased significantly from 125 (1.7) in 1980 to 242 (1.7) in 2003. Specifically, the serum concentrations of hexa (#138, #146, #153, #156, #163, and #164) and hepta (#170, #180, #182, and #187) congeners increased significantly. A comparison of the serum PCB levels of women born from 1940 to 1953 revealed that their serum total PCB level was significantly higher in the 2003 survey [242 (1.7), n = 9] than in the 1995 [128 (2.0), n = 17] surveys. This increase in the total PCB level was attributable to increases in the hepta congener groups.

CONCLUSION

Present results suggest a decreased rate of elimination of hepta congeners with aging in females, rather than a birth-generation phenomenon.

A decision framework for possible remediation of contaminated sediments in the River Kymijoki, Finland

BACKGROUND, AIM, AND SCOPE

The paper describes the spatial contamination of the River Kymijoki, South-Eastern Finland, and the coastal region of the Gulf of Finland with PCDD/Fs and mercury. The findings of ecotoxicologial and human health studies are also reported, including environmental and human risk assessments. Sediments from the River Kymijoki, draining into the Gulf of Finland, have been heavily polluted by the pulp and paper industry and by chemical industries. A wood preservative, known as Ky-5, was manufactured in the upper reaches of the river between 1940 and 1984 causing severe pollution of river sediments with polychlorinated dibenzo-p-dioxins (PCDD) and dibenzofurans (PCDF). Moreover, the sediments have been polluted with mercury (Hg) from chlor-alkali production and the use of Hg as a slimicide in pulp and paper manufacturing.

MATERIALS AND METHODS

An extensive sediment survey was conducted as well as sediment transport modeling, toxicity screening of sediment invertebrates, and a survey of contaminant bioaccumulation in invertebrates and fish. Studies on human exposure to PCDD/Fs and the possible effects on hypermineralization of teeth as well as an epidemiological study to reveal increased cancer risk were also conducted. An assessment of the ecological and human health risks with a null hypothesis (no remediation) was undertaken.

RESULTS

The sediment survey revealed severe contamination of river and coastal sediments with PCDD/Fs and Hg. The total volume of contaminated sediments was estimated to reach 5x10(6) m3 and hot spots with extremely high concentrations (max 292,000 ng g(-1) or 1,060 ng I-TEQ g(-1) d.w.) were located immediately downstream from the pollution source (approximately 90,000 m3). Sediment contamination was accompanied by changes in benthic assemblages, but direct effects were masked by many factors. The fish showed only slightly elevated PCDD/F levels in muscle, but orders of magnitude higher in the liver compared with reference freshwater sites and the Baltic Sea. The concentrations in human fat did not reveal high human exposure in the Kymijoki area in general and was lower than in sea fishermen. The relative risk for total cancer among farmers was marginally higher (RR=1.13) among those living close to the river, compared with farmers living further away, and the possibility of increased cancer risk cannot be ruled out. A conservative risk assessment revealed that the present probability of exceeding the WHO upper exposure limit of 4 pg WHO-TEQ kg(-1) d(-1) for PCDD/Fs and DL-PCBs was 6%. The probability of exceeding the WHO limit value of 0.23 mug kg(-1) d(-1) for methyl mercury was estimated to be notably higher at 62%. Based on these studies and the estimated risks connected with different remediation techniques a general remediation plan with cost benefit analysis was generated for several sub-regions in the river. Dredging, on-site treatment, and a close disposal of the most contaminated sediments (90,000 m3) was suggested as the first phase of the remediation. The decision regarding the start of remediation will be made during autumn 2008.

CONCLUSIONS

The sediments in the River Kymijoki are heavily polluted with PCDD/Fs and mercury from earlier chlorophenol, chlor-alkali, and pulp and paper manufacturing. A continuous transport of contaminants is taking place to the Gulf of Finland in the Baltic Sea. The highly increased PCDD/F and Hg levels in river sediments pose an ecotoxicological risk to benthic fauna, to fish-eating predators and probably to human health. The risks posed by mercury exceed those from PCDD/Fs and need to be evaluated for (former) chlor-alkali sites and other mercury releasing industries as one basis for remediation decision making.

RECOMMENDATIONS AND PERSPECTIVES

The studies form the basis of a risk management strategy and a plan for possible remediation of contaminated sediments currently under consideration in the Southeast Finland Regional Environment Centre. It is recommended that a detailed restoration plan for the most seriously contaminated areas should be undertaken. Based on current knowledge, the restoration of the whole river is not feasible, considering the current risk caused by the contaminated sediment in the river and the costs of an extensive restoration project. The experiences gained in the present case should be utilized in the evaluation of PCDD/F- and mercury-contaminated sites in other countries. The case demonstrates that the historic reservoirs are of contemporary relevance and should be addressed, e.g., in the national implementation plans of the Stockholm Convention.

Methodologic issues and approaches to spatial epidemiology

Spatial epidemiology is increasingly being used to assess health risks associated with environmental hazards. Risk patterns tend to have both a temporal and a spatial component; thus, spatial epidemiology must combine methods from epidemiology, statistics, and geographic information science. Recent statistical advances in spatial epidemiology include the use of smoothing in risk maps to create an interpretable risk surface, the extension of spatial models to incorporate the time dimension, and the combination of individual- and area-level information. Advances in geographic information systems and the growing availability of modeling packages have led to an improvement in exposure assessment. Techniques drawn from geographic information science are being developed to enable the visualization of uncertainty and ensure more meaningful inferences are made from data. When public health concerns related to the environment arise, it is essential to address such anxieties appropriately and in a timely manner. Tools designed to facilitate the investigation process are being developed, although the availability of complete and clean health data, and appropriate exposure data often remain limiting factors.

Connecting environmental health data to people and policy: integrating information and mobilizing communities for environmental public health tracking

Evaluation of available data is a critical preliminary step in the assessment of local environmental health. As part of a multi-organizational initiative to improve environmental health in the Pittsburgh, Pennsylvania region, the University of Pittsburgh Center for Healthy Environments and Communities (CHEC) interviewed 70 experts in the academic, government, non-profit, and private sectors and reviewed print and electronic resources to characterize environmental and public health data available in the region. The objectives of this undertaking were: to provide a conceptual framework for categorizing data locally on environmental hazards, exposures and health endpoints, to describe and evaluate the types of environmental public health data available nationally and locally, to identify existing endeavors to gather and categorize such data, and to present case studies on the real-life relevance of the availability or lack of availability of environmental health data. The purpose and relevance of this project, the evolution of the methodology, successes and challenges met, and anticipated next steps are presented. This process description and resulting comprehensive report is available to communities, at both the state and local health department level as well as lay community members, engaged in similar endeavors, to characterize their local and regional environmental health landscape. The framework outlined serves as background for a related statewide environmental health project sponsored by the Pennsylvania Department of Health through the Pennsylvania Consortium on Interdisciplinary Environmental Policy (PCIEP) and potentially as a foundation for community-based data evaluation for the National Environmental Public Health Tracking Program.

Health and environment information systems for exposure and disease mapping, and risk assessment

A large number of chemicals are used on a regular basis in modern society. Thousands of new chemicals are added each year, many of which may have toxic properties constituting potential health hazards. Rapid assessment of the risk associated with the use of these chemicals is therefore essential to protect people from exposure to potentially harmful substances. Exposures to chemicals (and physical agents) are typically unevenly distributed geographically as well as temporally. Disease occurrence also shows geographically varying patterns. Geographic information systems (GIS) may be used to produce maps of exposure and/or disease to reveal spatial patterns. Exposure mapping using advanced GIS modeling may enhance exposure assessment in environmental epidemiology studies. Disease maps can be valuable tools in risk assessment to explore changes in disease patterns potentially associated with changes in environmental exposures. Spatial variations in risk and trends related to distance from pollution sources may be studied using software tools such as the Rapid Inquiry Facility, developed by the U.K. Small Area Health Statistics Unit and enhanced in the European Health and Environment Information System project, for an initial quick evaluation of any potential health hazards associated with an environmental pollutant.