Residential proximity to petroleum storage tanks and associated cancer risks: Double Kernel Density approach vs. zonal estimates

Estimates of the global burden of cancer-related deaths attributable to residential exposure to petrochemical industrial complexes from 2020 to 2040

The petrochemical industry is a major industrial emitter of greenhouse gas (CO2) and environmental pollution, posing health risks to nearby communities. Although previous studies have indicated that residents living near petrochemical industrial complexes are at a higher risk of cancer, they have focused on local or regional burdens. This study aimed to estimate the global cancer burden attributable to residential exposure to petrochemical industrial complexes. The geographical coordinates of petrochemical plants and oil refineries were retrieved and verified from published sources. The ArcGIS software and global population data were used to estimate the number of people living within specific distances (exposed population). The exposure time window was framed as ranging from 1992 to 2035, extending to the latest period of the exposure time window for all cancer types to estimate the attributable deaths between 2020 and 2040. The relative risk of cancer was estimated from 15 published studies. Population attributable fraction (PAF) method was used to estimate the risk of cancer attributable to residential exposure and calculate the number of cancer-related deaths. Our findings indicate that >300 million people worldwide will be estimated to live near petrochemical industrial complexes by 2040. The overall global burden of cancer-related deaths was 19,083 in 2020, and it is estimated to increase to 27,366 deaths by 2040. The region with the highest attributable cancer deaths due to exposure is the high-income region, which had 10,584 deaths in 2020 and is expected to reach 13,414 deaths by 2040. Residential exposure to petrochemical industrial complexes could contribute to global cancer deaths, even if the proportion is relatively small, and proactive measures are required to mitigate the cancer burdens among these residents. Enforcing emissions regulations, improving monitoring, educating communities, and fostering collaboration are vital to protecting residents' health.

Assessing the environmental factors affecting the sustainability of Aini Falaj system

This study investigates the spatial distribution patterns and environmental factors influencing the Aini Falaj system in a specific study area. The research findings are presented through the lens of the following four categories: collinearity diagnostics, spatial autocorrelation analysis, kernel density (KD) findings, and multivariate geographically weighted regression (MGWR) analysis. The collinearity diagnostics were applied to examine the interrelationships among 18 independent environmental variables. The results indicate the absence of significant multicollinearity concerns, with most variables showing values below the critical threshold of five for variance inflation factors (VIFs). The selected variables indicate minimal intercorrelation, suggesting that researchers should be confident utilizing them in subsequent modelling or regression analyses. A spatial autocorrelation analysis using Moran's Index revealed positive spatial autocorrelation and significant clustering patterns in the distribution of live and non-functional Aini Falajs. High concentrations of live or dead Falajs tended to be surrounded by neighbouring areas with similar characteristics. These findings provide insights into the ecological preferences and habitat associations of Aini Falajs, thereby aiding conservation strategies and targeted studies. The kernel density (KD) analysis depicted distribution patterns of live and dry Aini Falajs through hotspots and cold spots. Specific regions exhibited high-density areas of live Falajs, indicating favourable environmental conditions or historical factors contributing to their concentrated distribution. Identifying these high-density zones can enhance our understanding of the spatial patterns and potential factors influencing the prevalence and sustainability of Aini Falajs. The multivariate geographically weighted regression (MGWR) models revealed strong associations between the live or dead status of Aini Falajs and environmental factors. The precipitation, topographic wetness index (TWI), aspect and slope exerted positive impacts on the live status, while evaporation, solar radiation, distance to drains and drain density exerted negative influences. Similar associations were observed for the dead status, emphasising the importance of controlling evaporation, shading mechanisms, proper drainage planning and sustainable land-use practices. This study provides valuable insights into the spatial distributions and factors influencing the live and dead status of Aini Falajs, thereby contributing to our understanding of their ecological dynamics and guiding conservation efforts and management strategies.

Marine Air Pollution in Israel: Extent, Proposed Mitigation Targets, Benefits and Feasibility

Marine air pollution is a major contributor to seaports and coastal air pollution, and Israel has yet to seriously confront this issue. This study aimed to update previous marine air pollution estimations in Israel’s two major ports: Haifa and Ashdod. The objectives were to examine technical and regulatory measures to address the problem, to propose mitigation targets and to estimate their potential benefits. Based on a model of emission-calculations that relies on an updated ship-inventory data as well as real-time ships’ location and movement tools, the combined marine NOx, SOx and PM2.5 annual emissions in these ports were found to be 18,415, 15,128 and 1453 tons, respectively. These values are considerably higher than previous estimates, are comparable to the constant pollution emitted at ground level from a 1000-MW coal powered city power plant and are 3–20 times higher than the industrial and land transportation sectors in these cities. Relatively high nickel concentration in PM was found in Israel only relatively adjacent to the Haifa and Ashdod ports. Since high nickel concentration in PM is today mainly associated with marine air pollution, this finding supports the hypothesis that marine air pollution worsens the air quality in these cities. SOx and PM2.5 emissions can be reduced by 78% and 27%, respectively, if Israel enforces the revised International Convention for the Prevention of Pollution from Ships (MARPOL) Annex VI regulations in its territorial waters. While the latter step can achieve external benefits of NIS 518.4 million/year (EUR 132 million/year), additional mitigation actions and local regulations are suggested, focusing on NOx emissions but also on other pollutant criteria. Such actions can achieve further benefits of NIS 274.3 million/year (EUR 70 million/year). Achieving the suggested targets is challenging yet attainable, and their potential benefits will probably outweigh their costs.

The effect of exposure to crude oil on the immune system. Health implications for people living near oil exploration activities

People who reside near oil exploration activities may be exposed to toxins from gas flares or oil spills. The impact of such exposures on the human immune system has not been fully investigated. In this review, research investigating the effects of crude oil on the immune system is evaluated. The aim was to obtain a greater understanding of the possible immunological impact of living near oil exploration activities. In animals, the effect of exposure to crude oil on the immune system depends on the species, dose, exposure route, and type of oil. Important observations included; hematological changes resulting in anemia and alterations in white blood cell numbers, lymph node and splenic atrophy, genotoxicity in immune cells, modulation of cytokine gene expression and increased susceptibility to infectious diseases. In humans, there are reports that exposure to crude oil can increase the risk of developing certain types of cancer and cause immunomodulation.Abbreviations: A1AT: alpha-1 antitrypsin; ACH₅₀: hemolytic activity of the alternative pathway; AHR: aryl hydrocarbon receptor; BALF: bronchoalveolar lavage fluid; COPD: chronic obstructive pulmonary disease; CYP: cytochrome P450; DNFB: 2, 4-dinitro-1-fluorobenzene; G-CSF: granulocyte-colony stimulating factor; IFN: interferon; IL: interleukin; 8-IP: 8-isoprostane; ISG15: interferon stimulated gene; LPO: lipid peroxidation; LTB₄: leukotriene B₄; M-CSF: macrophage-colony stimulating factor; MMC: melanomacrophage center; MPV: mean platelet volume; NK: natural killer; OSPM: oil sail particulate matter; PAH: polycyclic aromatic hydrocarbon; PBMC: peripheral blood mononuclear cell; PCV: packed cell volume; RBC: red blood cell; ROS: reactive oxygen species; RR: relative risk; T_H: T helper; TNF: tumour necrosis factor; UV: ultraviolet; VNNV: Viral Nervous Necrosis Virus; WBC: white blood cell.

Long-term exposure to PM2.5 and its constituents and risk of Non-Hodgkin lymphoma in Denmark: A population-based case-control study

BACKGROUND

Particulate matter (PM) air pollution is a complex mixture and the various PM constituents likely affect health differently. The literature on the relationships among specific PM constituents and the risk of cancer is sparse. In this study, we aimed to evaluate the association of PM_2.5 and its constituents with the incidence of non-Hodgkin lymphoma (NHL) and the two main NHL subtypes.

METHODS

We undertook a nationwide register-based case-control study including 20,847 cases registered in the Danish Cancer Registry with NHL between 1989 and 2014. Among the entire Danish population, we selected 41,749 age and sex-matched controls randomly from the Civil Registration System. We assessed modelled outdoor PM concentrations at addresses of cases and controls with a state-of-the-art multi scale air pollution modelling system and used conditional logistic regression to estimate odds ratios (ORs) adjusted for individual and neighborhood level socio-demographic variables.

RESULTS

The 10-year time-weighted average concentrations of PM_2.5, primary carbonaceous particles (BC/OC), secondary inorganic aerosols (SIA), secondary organic aerosols (SOA) and sea salt were 17.4, 2.3, 7.8, 0.3, and 4.1 μg/m³, respectively among controls. The results showed higher risk for NHL in association with exposure to BC/OC (OR = 1.03; 95% CI: 1.00, 1.07, per interquartile range (IQR)) and SOA (OR = 1.54; 95% CI: 1.13, 2.09, per IQR). The results indicated a higher risk for follicular lymphoma in association with several PM components. Including PM_2.5 (OR = 1.16; 95% CI: 0.98-1.38), BC/OC (OR = 1.05; 95% CI: 0.97-1.14), SIA (OR = 1.44; 95% CI: 0.80-1.08), SOA (OR = 4.52; 95% CI: 0.86-23.83) per IQR.

CONCLUSION

This is the first study on PM constituents and the risk of NHL. The results indicated an association with primary carbonaceous and secondary organic PM. The results need replication in other settings before any firm conclusion can be reached.

Cancer Incidence Trends in the Oil Shale Industrial Region in Estonia

Large oil shale resources are found in Eastern Estonia, where the mineral resource is mined, excavated, and used for electricity generation and shale oil extraction. During industrial activities in the last 100 years, pollutants have been emitted in large amounts, some of which are toxic and carcinogenic. The current study aims to analyse time trends in cancer incidence in the oil shale industry-affected areas and compare them with overall cancer incidence rates and trends in Estonia. We analysed Estonian Cancer Registry data on selected cancer sites that have been previously indicated to have relationships with industrial activities like oil shale extraction. We included lung cancer, kidney cancer, urinary bladder cancer, leukaemia, breast cancer, and non-Hodgkin's lymphoma. A statistically significantly higher lung cancer age-standardized incidence rate (ASIR) was found during the study period (1992-2015) only in males in the oil shale areas as compared to males in Estonia overall: 133.6 and 95.5 per 100,000, respectively. However, there appeared to be a statistically significant (p < 0.05) decrease in the lung cancer ASIR in males in the oil shale areas (overall decrease 28.9%), whereas at the same time, there was a significant increase (p < 0.05) in non-oil shale areas (13.3%) and in Estonia overall (1.5%). Other cancer sites did not show higher ASIRs in the oil shale industrial areas compared to other areas in Estonia. Possible explanations could be improved environmental quality, socio-economic factors, and other morbidities.

A systematic review and meta-analysis of haematological malignancies in residents living near petrochemical facilities

BACKGROUND

The petrochemical industry is a major source of hazardous and toxic air pollutants that are recognised to have mutagenic and carcinogenic properties. A wealth of occupational epidemiology literature exists around the petrochemical industry, with adverse haematological effects identified in employees exposed to 'low' concentrations of aromatic hydrocarbons (benzene, toluene, ethylbenzene, and xylene). Releases from the petrochemical industry are also thought to increase the risk of cancer incidence in fenceline communities. However, this emerging and at times inconclusive evidence base remains fragmented. The present study's aim was to conduct a systematic review and meta-analysis of epidemiological studies investigating the association between incidences of haematological malignancy and residential exposure to the petrochemical industry.

METHODS

Epidemiological studies reporting the risk of haematological malignancies (Leukaemia, Hodgkin's lymphoma, Non-Hodgkin's lymphoma, and Multiple myeloma) were included where the following criteria were met: (i) Cancer incidence is diagnosed by a medical professional and coded in accordance to the International Classification of Diseases; (ii) A clear definition of fenceline communities is provided, indicating the proximity between exposed residents and petrochemical activities; and (iii) Exposure is representative of normal operating conditions, not emergency events. Two investigators independently extracted information on study characteristics and outcomes in accordance with PRISMA and MOOSE guidelines. Relative risks and their 95% confidence intervals were pooled across studies for the four categories of haematological malignancy, using a random effects meta-analysis.

RESULTS

The systematic review identified 16 unique studies, which collectively record the incidence of haematological malignancies across 187,585 residents living close to a petrochemical operation. Residents from fenceline communities, less than 5 km from a petrochemical facility (refinery or manufacturer of commercial chemicals), had a 30% higher risk of developing Leukaemia than residents from communities with no petrochemical activity. Meanwhile, the association between exposure and rarer forms of haematological malignancy remains uncertain, with further research required.

CONCLUSIONS

The risk of developing Leukaemia appears higher in individuals living near a petrochemical facility. This highlights the need for further policy to regulate the release of carcinogens by industry.

Long-term exposure to air pollution and risk of non-Hodgkin lymphoma in Denmark: A population-based case-control study

There is limited evidence regarding a possible association between exposure to ambient air pollutants and the risk of non-Hodgkin lymphoma (NHL). Previous epidemiological studies have relied on crude estimations for air pollution exposure and/or small numbers of NHL cases. The objective of our study was to analyze this association based on air pollution modeled at the address level and NHL cases identified from the nationwide Danish Cancer Registry. We identified 20,874 incident NHL cases diagnosed between 1989 and 2014 and randomly selected 41,749 controls matched on age and gender among the entire Danish population. We used conditional logistic regression to estimate odds ratios (ORs) and adjusted for individual and neighborhood level sociodemographic variables. There was no association between exposure to PM_2.5 , BC, O₃ , SO₂ or NO₂ and overall risk of NHL but several air pollutants were associated with higher risk of follicular lymphoma, but statistically insignificant, for example, PM_2.5 (OR = 1.15 per 5 μg/m³ ; 95% CI: 0.98-1.34) and lower risk for diffuse large B-cell lymphoma (OR = 0.92 per 5 μg/m³ ; 95% CI: 0.82-1.03). In this population-based study, we did not observe any convincing evidence of a higher overall risk for NHL with higher exposure to ambient air pollutants.

Forecasting health effects potentially associated with the relocation of a major air pollution source

Epidemiological studies often focus on risk assessments associated with exposures to specific air pollutants or proximity to different air pollution sources. Although this information is essential for devising informed health policies, it is not always helpful when it comes to the estimation of potential health effects associated with the introduction or relocation of local health hazards. In this paper, we suggest a novel approach to forecasting the morbidity-reduction impact of hypothetical removal of a major air pollution source from a densely populated urban area. The proposed approach is implemented in three stages. First, we identify and measure the strength of association of individual environmental factors with local morbidity patterns. Next, we use the estimated models to simulate the impact of removal of the pollution source under analysis and its replacement by green areas. Using this assessment, we then estimate potential changes in the local morbidity rates by mutually comparing the observed risk surface of disease with the risk surface simulated by modelling. To validate the proposed approach empirically, we use childhood asthma morbidity data available for a major metropolitan area in Israel, which hosts a large petrochemical complex. According to our estimates, relocation of the petrochemical complex in question is expected to result in about 70% drop in the childhood asthma morbidity rate area-wide. To the best of our knowledge, the present study is the first that suggests an operational approach to incorporating epidemiological assessments as an input for urban development plans related to local sources of air pollution.

Spatial identification of environmental health hazards potentially associated with adverse birth outcomes

Reduced birth weight (RBW) and reduced head circumference (RHC) are adverse birth outcomes (ABOs), often linked to environmental exposures. However, spatial identification of specific health hazards, associated with these ABOs, is not always straightforward due to presence of multiple health hazards and sources of air pollution in urban areas. In this study, we test a novel empirical approach to the spatial identification of environmental health hazards potentially associated with the observed RHC and RBW patterns. The proposed approach is implemented as a systematic search, according to which alternative candidate locations are ranked based on the strength of association with the observed birth outcome patterns. For empirical validation, we apply this approach to the Haifa Bay Area (HBA) in Israel, which is characterized by multiple health hazards and numerous sources of air pollution. We identified a spot in the local industrial zone as the main risk source associated with the observed RHC and RBW patterns. Multivariate regressions, controlling for personal, neighborhood, and geographic factors, revealed that the relative risks of RHC and RBW tend to decline, other things being equal, as a function of distance from the identified industrial spot. We recommend the proposed identification approach as a preliminary risk assessment tool for environmental health studies, in which detailed information on specific sources of air pollution and air pollution dispersion patterns is unavailable due to limited reporting or insufficient monitoring.

Risks and burden of lung cancer incidence for residential petrochemical industrial complexes: A meta-analysis and application

BACKGROUND

Lung cancer is one of the most common cancers in the world. Higher incidence of lung cancer may be associated with residential proximity to a petrochemical industrial complex (PIC) due to exposure to various carcinogens, although results from previous epidemiologic studies remain inconclusive. Because disease burden due to residential inequality is a public health and societal concern, this study analyzed published data to estimate lung cancer incidence in association with residential proximity to PICs.

METHODS

We performed a meta-analysis on selected epidemiologic studies that met the following criteria: lung cancer incidence was coded by the International Classification of Diseases; exposure groups were clearly defined as residents living near PICs; and confidence intervals were available or calculable from original articles. We further applied a population attributable factor (PAF) method to estimate disease burden attributable to living near PICs in 22 European Union (EU) countries.

RESULTS

Meta-analysis included six studies with a total of 466,066 residents living near PICs in six countries. Residents living near PICs had a 19% higher risk of lung cancer compared to those who lived farther away (95% CI = 1.06-1.32). By sex, risks were higher and more significant for females (RR = 1.29; 95% CI = 1.09-1.54; P = 0.004) than males (RR = 1.12; 95% CI = 0.95-1.33; P = 0.173). By location, only groups in Europe had a significantly greater risk of lung cancer with exposure to PICs (95% CI = 1.03-1.33; P = 0.019), although groups in other locations showed similar trends. By bona fide observation, observation of residents for at least seven years provided sufficient latency to estimate risk (RR = 1.25; 95% CI = 1.17-1.34; P < 0.001). Regarding burden of lung cancer in 22 EU countries, 494 males and 478 females were attributed to living in the vicinity of a PIC annually.

CONCLUSIONS

Lung cancer incidence is significantly higher in individuals living near PICs. This result provides strong epidemiologic evidence for further policy to regulate potential pollutants near PICs.

HIGHLIGHTS

Higher incident rates of lung cancer for residents living close to petrochemical industry complex.

Environmental risk factors associated with low birth weight: The case study of the Haifa Bay Area in Israel

BACKGROUND

Low birth weight (LBW) is known to be associated with infant mortality and postnatal health complications. Previous studies revealed strong relationships between LBW rate and several socio-demographic factors, including ethnicity, maternal age, and family income. However, studies of association between LBW rate and environmental risk factors remain infrequent.

STUDY METHODS

We retrieved a geo-referenced data set, containing 7216 individual records of children born in 2015 in the Haifa Bay Area in Israel. Using this dataset, we analysed factors affecting LBW prevalence by applying two alternative techniques: analysis of LBW rates in small census area (SCAs) and more recently developed double kernel density (DKD) relative risk (RR) estimates.

RESULTS

In the SCA models, LBW rate was found to be associated with proximity to petrochemical industries (B=-0.26, 95%CI=-0.30, -0.22), road density (B=0.05, 95%CI=0.02, 0.08), distance to the seashore (B=0.17, 95%CI=0.14, 0.22), PM_2.5 (B=0.06, 95%CI=0.04, 0.09) and NO_x (B=0.10, 95%CI=0.06, 0.13) exposure estimates. Although similar factors emerged in the DKD models as well, in most cases, the effects of these factors in the latter models were found to be stronger: proximity to petrochemical industries (B=-0.48, 95%CI= -0.51, -0.30), road density (B=0.05, 95%CI=0.02, 0.08), distance to the seashore (B=0.24, 95%CI=0.21, 0.27), PM_2.5 (B=0.08, 95%CI=0.05, 0.10) and NO_x (B=0.20, 95%CI=0.17, 0.23) exposure estimates. In addition, elevation above the sea level was found to be statistically significant in spatial dependence models estimated for both DKD and SCA rates (P < 0.01).

CONCLUSION

The analysis revealed an excess LBW rate in residential areas located close to petrochemical industries and a protective effect of seashore proximity and elevation above the sea level on the LBW rate. We attribute the latter finding to the moderating effect of elevated seashore locations on outdoor temperatures during the hot summer season.

Kernel density analysis reveals a halo pattern of breast cancer incidence in Connecticut

Breast cancer (BC) incidence rates in Connecticut are among the highest in the United States, and are unevenly distributed within the state. Our goal was to determine whether artificial light at night (ALAN) played a role. Using BC records obtained from the Connecticut Tumor Registry, we applied the double kernel density (DKD) estimator to produce a continuous relative risk surface of a disease throughout the State. A multi-variate analysis compared DKD and census track estimates with population density, fertility rate, percent of non-white population, population below poverty level, and ALAN levels. The analysis identified a "halo" geographic pattern of BC incidence, with the highest rates of the disease observed at distances 5-15 km from the state's major cities. The "halo" was of high-income communities, with high ALAN, located in suburban fringes of the state's main cities.

Mapping outdoor habitat and abnormally small newborns to develop an ambient health hazard index

Background

The geography of where pregnant mothers live is important for understanding outdoor environmental habitat that may result in adverse birth outcomes. We investigated whether more babies were born small for gestational age or low birth weight at term to mothers living in environments with a higher accumulation of outdoor hazards.

Methods

Live singleton births from the Alberta Perinatal Health Program, 2006–2012, were classified according to birth outcome, and used in a double kernel density estimation to determine ratios of each outcome per total births. Individual and overlay indices of spatial models of 136 air emissions and 18 land variables were correlated with the small for gestational age and low birth weight at term, for the entire province and sub-provincially.

Results

There were 24 air substances and land sources correlated with both small for gestational age and low birth weight at term density ratios. On the provincial scale, there were 13 air substances and 2 land factors; sub-provincial analysis found 8 additional air substances and 1 land source.

Conclusion

This study used a combination of multiple outdoor variables over a large geographic area in an objective model, which may be repeated over time or in other study areas. The air substance-weighted index best identified where mothers having abnormally small newborns lived within areas of potential outdoor hazards. However, individual air substances and the weighted index provide complementary information.

A new approach to spatial identification of potential health hazards associated with childhood asthma

RESEARCH BACKGROUND

Childhood asthma is a chronic disease, known to be linked to prolonged exposure to air pollution. However, the identification of specific health hazards, associated with childhood asthma is not always straightforward, due to the presence of multiple sources of air pollution in urban areas. In this study, we test a novel approach to the spatial identification of environmental hazards that have the highest probability of association with the observed asthma morbidity patterns.

METHODS

The effect of a particular health hazard on population morbidity is expected to weaken with distance. To account for this effect, we rank potential health hazards based on the strength of association between the observed morbidity patterns and wind-direction weighted proximities to these locations. We validate this approach by applying it to a study of spatial patterns of childhood asthma in the Greater Haifa Metropolitan Area (GHMA) in Israel, characterised by multiple health hazards.

RESULTS

We identified a spot in the local industrial zone as the primary risk source for the observed asthma morbidity patterns. Multivariate regressions, controlling for socio-economic and geographic variables, revealed that the observed incidence rates of asthma tend to decline as a function of distance from the identified industrial location.

CONCLUSION

The proposed identification approach uses disease patterns as its main input, and can be used by researches as a preliminary risk assessment tool, in cases in which specific sources of locally elevated morbidity are unclear or cannot be identified by traditional methods.

Spatial identification of potential health hazards: a systematic areal search approach

Background and aims

Large metropolitan areas often exhibit multiple morbidity hotspots. However, the identification of specific health hazards, associated with the observed morbidity patterns, is not always straightforward. In this study, we suggest an empirical approach to the identification of specific health hazards, which have the highest probability of association with the observed morbidity patterns.

Methods

The morbidity effect of a particular health hazard is expected to weaken with distance. To account for this effect, we estimate distance decay gradients for alternative locations and then rank these locations based on the strength of association between the observed morbidity and wind-direction weighted proximities to these locations. To validate this approach, we use both theoretical examples and a case study of the Greater Haifa Metropolitan Area (GHMA) in Israel, which is characterized by multiple health hazards.

Results

In our theoretical examples, the proposed approach helped to identify correctly the predefined locations of health hazards, while in the real-world case study, the main health hazard was identified as a spot in the industrial zone, which hosts several petrochemical facilities.

Conclusion

The proposed approach does not require extensive input information and can be used as a preliminary risk assessment tool in a wide range of environmental settings, helping to identify potential environmental risk factors behind the observed population morbidity patterns.

Electronic supplementary material

The online version of this article (doi:10.1186/s12942-017-0078-8) contains supplementary material, which is available to authorized users.

Unconventional oil and gas development and risk of childhood leukemia: Assessing the evidence

The widespread distribution of unconventional oil and gas (UO&G) wells and other facilities in the United States potentially exposes millions of people to air and water pollutants, including known or suspected carcinogens. Childhood leukemia is a particular concern because of the disease severity, vulnerable population, and short disease latency. A comprehensive review of carcinogens and leukemogens associated with UO&G development is not available and could inform future exposure monitoring studies and human health assessments. The objective of this analysis was to assess the evidence of carcinogenicity of water contaminants and air pollutants related to UO&G development. We obtained a list of 1177 chemicals in hydraulic fracturing fluids and wastewater from the U.S. Environmental Protection Agency and constructed a list of 143 UO&G-related air pollutants through a review of scientific papers published through 2015 using PubMed and ProQuest databases. We assessed carcinogenicity and evidence of increased risk for leukemia/lymphoma of these chemicals using International Agency for Research on Cancer (IARC) monographs. The majority of compounds (>80%) were not evaluated by IARC and therefore could not be reviewed. Of the 111 potential water contaminants and 29 potential air pollutants evaluated by IARC (119 unique compounds), 49 water and 20 air pollutants were known, probable, or possible human carcinogens (55 unique compounds). A total of 17 water and 11 air pollutants (20 unique compounds) had evidence of increased risk for leukemia/lymphoma, including benzene, 1,3-butadiene, cadmium, diesel exhaust, and several polycyclic aromatic hydrocarbons. Though information on the carcinogenicity of compounds associated with UO&G development was limited, our assessment identified 20 known or suspected carcinogens that could be measured in future studies to advance exposure and risk assessments of cancer-causing agents. Our findings support the need for investigation into the relationship between UO&G development and risk of cancer in general and childhood leukemia in particular.

Application of the double kernel density approach to the analysis of cancer incidence in a major metropolitan area

RATIONALE

Although cancer is a main cause of human morbidity worldwide, relatively small numbers of new cancer cases are recorded annually in single urban areas. This makes the association between cancer morbidity and environmental risk factors, such as ambient air pollution, difficult to detect using traditional methods of analysis based on age standardized rates and zonal estimates.

STUDY GOAL

The present study investigates the association between air pollution and cancer morbidity in the Greater Haifa Metropolitan Area in Israel by comparing two analytical techniques: the traditional zonal approach and more recently developed Double Kernel Density (DKD) tools. While the first approach uses age adjusted Standardized Incidence Ratios (SIRs) for small census areas, the second approach estimates the areal density of cancer cases, normalized by the areal density of background population in which cancer events occurred. Both analyses control for several potential confounders, including air pollution, proximities to main industrial facilities and socio-demographic attributes.

RESULTS

Air pollution variables and distances to industrial facilities emerged as statistically significant predictors of lung and NHL cancer morbidity in the DKD-based models (p<0.05) but not in the models based on SIRs estimates (p>0.2).

CONCLUSION

DKD models appear to be a more sensitive tool for assessing potential environmental risks than traditional SIR-based models, because DKD estimates do not depend on a priory geographic delineations of statistical zones and produce a smooth and continuous disease 'risk surface' covering the entire study area. We suggest using the DKD method in similar studies of the effect of ambient air pollution on chronic morbidity, especially in cases in which the number of statistical areas available for aggregation and comparison is small and recorded morbidity events are relatively rare.

Persistence of Breakage in Specific Chromosome Bands 6 Years after Acute Exposure to Oil

BACKGROUND

The identification of breakpoints involved in chromosomal damage could help to detect genes involved in genetic disorders, most notably cancer. Until now, only one published study, carried out by our group, has identified chromosome bands affected by exposure to oil from an oil spill. In that study, which was performed two years after the initial oil exposure in individuals who had participated in clean-up tasks following the wreck of the Prestige, three chromosomal bands (2q21, 3q27, 5q31) were found to be especially prone to breakage. A recent follow-up study, performed on the same individuals, revealed that the genotoxic damage had persisted six years after oil exposure.

OBJECTIVES

To determine whether there exist chromosome bands which are especially prone to breakages and to know if there is some correlation with those detected in the previous study. In addition, to investigate if the DNA repair problems detected previously persist in the present study.

DESIGN

Follow-up study performed six years after the Prestige oil spill.

SETTING

Fishermen cooperatives in coastal villages.

PARTICIPANTS

Fishermen highly exposed to oil spill who participated in previous genotoxic study six years after the oil.

MEASUREMENTS

Chromosome damage in peripheral lymphocytes. For accurate identification of the breakpoints involved in chromosome damage of circulating lymphocytes, a sequential stain/G-banding technique was employed. To determine the most break-prone chromosome bands, two statistical methods, the Fragile Site Multinomial and the chi-square tests (where the bands were corrected by their length) were used. To compare the chromosome lesions, structural chromosome alterations and gaps/breaks between two groups of individuals we used the GEE test which takes into account a possible within-individual correlation. Dysfunctions in DNA repair mechanisms, expressed as chromosome damage, were assessed in cultures with aphidicolin by the GEE test.

RESULTS

Cytogenetic analyses were performed in 47 exposed individuals. A total of 251 breakpoints in exposed individuals) were identified, showing a non-uniform distribution in the human ideogram. Ten chromosome bands were found to be especially prone to breakage through both statistical methods. By comparing these bands with those observed in certain exposed individuals who had already participated the previous study, it was found in both studies that four bands (2q21, 3q27, 5q31 and 17p11.2) are particularly sensitive to breakage. Additionally, the dysfunction in DNA repair mechanisms was not significantly higher in oil-exposed individuals than in non-exposed individuals.

LIMITATIONS

The sample size and the possibility of some kind of selection bias should be considered. Genotoxic results cannot be extrapolated to the high number of individuals who participated occasionally in clean-up tasks.

CONCLUSION

Our findings show the existence of at least four target bands (2q21, 3q27, 5q31 and 17p11.2) with a greater propensity to break over time after an acute exposure to oil. The breaks in these bands, which are commonly involved in hematological cancer, may explain the increase of cancer risk reported in chronically benzene-exposed individuals. In addition, a more efficiency of the DNA repair mechanisms has been detected six years after in fishermen who were highly exposed to the oil spill. To date, only this study, performed by our group on the previous and present genotoxic effects, has analyzed the chromosomal regions affected by breakage after an acute oil exposure.

Spatial autocorrelation of cancer incidence in Saudi Arabia

Little is known about the geographic distribution of common cancers in Saudi Arabia. We explored the spatial incidence patterns of common cancers in Saudi Arabia using spatial autocorrelation analyses, employing the global Moran's I and Anselin's local Moran's I statistics to detect nonrandom incidence patterns. Global ordinary least squares (OLS) regression and local geographically-weighted regression (GWR) were applied to examine the spatial correlation of cancer incidences at the city level. Population-based records of cancers diagnosed between 1998 and 2004 were used. Male lung cancer and female breast cancer exhibited positive statistically significant global Moran's I index values, indicating a tendency toward clustering. The Anselin's local Moran's I analyses revealed small significant clusters of lung cancer, prostate cancer and Hodgkin's disease among males in the Eastern region and significant clusters of thyroid cancers in females in the Eastern and Riyadh regions. Additionally, both regression methods found significant associations among various cancers. For example, OLS and GWR revealed significant spatial associations among NHL, leukemia and Hodgkin's disease (r² = 0.49-0.67 using OLS and r² = 0.52-0.68 using GWR) and between breast and prostate cancer (r² = 0.53 OLS and 0.57 GWR) in Saudi Arabian cities. These findings may help to generate etiologic hypotheses of cancer causation and identify spatial anomalies in cancer incidence in Saudi Arabia. Our findings should stimulate further research on the possible causes underlying these clusters and associations.