Predictors of Beta-Hexachlorocyclohexane blood levels among people living close to a chemical plant and an illegal dumping site

BACKGROUND

Hexachlorocyclohexane is a synthetic chemical with several isomers, including β-Hexachlorocyclohexane (β-HCH). In 2005, a large contamination of crude milk from some bovine farms along the Sacco River (Central Italy) was detected; it was related to the illegal disposal of large quantities of processing waste by a chemical industry of the area. A biomonitoring study, conducted in 2007 on a sample of the residing population, found high values of β-HCH in people living close to the river. These results led to the establishment of a clinical and epidemiological surveillance program on all the exposed population. The aim of the study was to evaluate the determinants of β-HCH blood levels in people living within 1 Km of the Sacco River, focusing on the role of specific foods, body mass index and risk factors not yet identified.

METHODS

The program involved all people living within 1 km of the river. A descriptive analysis of β-HCH blood levels was done in relation to the potential determinants including specific foods. Regression analysis was used to study the association between potential determinants and (natural log) β-HCH haematic concentration. The results were expressed as geometric mean ratios (GMR). To take into account similarities within the families we adjusted for family clustering.

RESULTS

A total of 602 subjects (87.2%) agreed to participate in the surveillance. The β-HCH geometric mean serum concentration was 72 ng/g lipid. The regression analysis showed that being female (GMR: 1.32, 95%CI: 1.14-1.53), elderly (GMR_{> 70yy}: 10.04, 95%CI: 6.65-15.15), obese (GMR: 1.63, 95%CI: 1.28-2.08), eating food of local/own production (GMR 1.47, 95%CI: 1.15-1.88) and using water from private wells (GMR_drink:1.47, 95%CI: 1.00-2.14 and GMR_wash: 1.48, 95%CI: 1.17-1.87) were associated with higher β-HCH values. There was inverse association with breastfeeding (GMR: 0.64, 95%CI: 0.47-0.86). The focus on specific foods showed that the most important factors were eggs and beef.

CONCLUSIONS

The study indicated a greater contamination for older people, and those drinking and washing with water from private wells and consuming locally produced food, especially eggs and beef.

[Malignant mesothelioma in the industrial area of Colleferro]

The study describes the occurrence of pleural and peritoneal malignant mesothelioma in the Colleferro industrial area (Province of Rome, 9 municipalities, population 63,000, period 1993-98) which is the site of a large chemical plant (BPD) producing organic chemicals, acid mixtures, insecticides, explosives and dynamite, and was involved in manufacturing/maintenance of railroad rolling stock. Asbestos was extensively used in these plants in the past. Mesothelioma cases were actively searched from data in files of pathology archives, hospital admission and discharge (records), and death certificates recorded at local health authority register. 23 potential cases were identified for whom clinical charts and pathological slides were reviewed. A multidisciplinary evaluation of all collected information confirmed 18 cases of cyto-histologically proven malignant mesothelioma (pleural/peritoneal ratio of 2.75:1) among residents and/or workers at BPD. The remaining 5 cases were defined as not mesothelioma; however, two were cases of lung cancer (both occupationally exposed to asbestos). All subjects with malignant mesothelioma had been occupationally exposed to asbestos (14 males and 3 females), except one (1 female with domestic exposure). No mesothelioma case was attributable to environmental exposure. Of the 17 cases with occupational asbestos exposure, 15 occurred in BPD workers employed in manufacturing/maintenance of railroad rolling stock (3 cases), general maintenance services (5 cases), or in the armaments sector (7 cases) and 2 in residents but not BPD workers (1 baker, 1 pipefitter). The incidence rate in residents of the 9 municipalities was 5.5 in males and 1.3 in females (standardized on the Italian population x100,000, census 1981). For Colleferro municipality only, the incidence was 10.1 in males and 4.1 in females, which are the highest rates reported so far in Italy. Besides confirming the risk of mesothelioma risk in railroad rolling stock manufacturing and asbestos-insulated pipe maintenance workers, this study identifies a cluster of malignant mesothelioma in explosives production workers.

Cancer mortality among chemical workers in an Italian plant

Objective of this study was to assess the mortality experience of a cohort of chemical workers at a plant located in central Italy. Subjects employed for any time between 1954 and 1970 at the chemical plant were included in the cohort and followed up to June 1991. The workers were classified as having ever/never worked in one of the following work processes: organic chemicals, acid mixtures, cleansing agents and insecticides. Mortality experience of the cohort was compared with that of the regional population by computing SMRs (standardized mortality ratios) and 90% CI (confidence intervals). Vital status was ascertained for 96% of the 505 cohort members. All causes of mortality for the entire cohort were lower than expected (Obs: 176; SMR: 0.90; 90% CI: 0.79-1.03). Analysis by work process revealed an increased mortality for lymphatic and hematopoietic tissue neoplasm in the cleansing agents department (Obs: 3; SMR: 5.00; 90% CI: 1.36-12.9); peritoneum and retropertioneum neoplasm in the organic compounds production (Obs: 2; SMR: 13.33; 90% CI: 2.37-42.0), and bladder cancer in the insecticides process (Obs: 3; SMR: 3.53; 90% CI: 0.96-9.12). Although the study had a low statistical power, the increased cancer risks detected are consistent with previous observations and may be of etiologic interest.

[Mortality study of workers employed in the construction of railway cars in Collefero]

The mortality of 276 workers employed in a facility for the manufacturing and maintenance of railroad equipment has been studied in the town of Colleferro (province of Rome). The cohort was based on the 1968 payrolls, and follow-up was conducted up to 1988. Exposure to asbestos took place both during insulation (performed by specialized companies in the same workplaces where study subjects were operating) and during repair work. Mortality for all causes was lower than expected (45 observed, SMR: 71), while mortality from all neoplasms was consistent with expected figures (21 observed, SMR: 107). An increase for respiratory neoplasms was observed (10 observed, SMR: 138); the increase was statistically significant allowing for 20-30 years of latency (7 observed, SMR: 337).