Effects of dredging at Aratu port in All Saints Bay, Brazil: monitoring the metal content in water and sediments

This work reports the chemical monitoring of saline water and sediments at Aratu port, All Saints Bay, Brazil, when subjected to a deep dragging process (DDP) over a 2-year period (2010-2012). The aim of this work was to detect which metals had possible deleterious effects on the biota. It analyzed percentage of silt + clay and TOC and metal concentrations (As, Cd, Cu, Cr, Ni, Pb, and Zn) before, during, and after the DDP. The determination of metal concentration in sediments used the following techniques: atomic absorption spectrometer with flame, also with hydrate generation, and cold vapor spectrophotometry. The DDP disturbed the concentrations of metals in sediments and water, but 15 months after the DDP, only Cu and Zn were detectable on the bottom saline water, and 20 months after the DDP, only Zn was detectable in water. This fact indicates that these metals were longer available for absorption by the marine biota with probable deleterious effect. Indeed, studies by others during the DDP in Aratu port, indicated the decrease from 50 to 40 of the number of microalgae species identified. On the other hand, in the sediments, 20 months after the DDP, the concentrations of As, Cr, Cu, Pb, and Hg, returned to the original values, but Ni and Zn did not return to their original values. Comparison with studies by others indicated that the sediments from dredging were inappropriate for disposal at sea. This work indicated that the metals Cu, Ni, and Zn are the most deleterious elements to the marine environment.

Incidence of lymphohaematopoietic malignancies in a petrochemical industry cohort: 1983-94 follow up

OBJECTIVES

In response to a previous finding of increased mortality from lymphohaematopoietic (LH) malignancies, this study examines incidence of LH malignancy in a petrochemical industry cohort. Emphasis is on chronic lymphocytic leukaemia (CLL) and on comparisons by period of first employment.

METHOD

The study cohort consists of 8942 employees who were active in the period 1970-92 and alive on 31 December 1982. Record linkage with the Louisiana tumour registry (LTR) provided information on cancer for cases occurring between 1983 and 1994. Standardised incidence ratios (SIR), with the south Louisiana population as a comparison, were computed for all cancers, all LH malignancies and specific LH subtypes. Analyses were conducted for sex and race categories, and by period of first employment, job type, duration of employment, and latency.

RESULTS

672 Cases of cancer were identified, including 59 LH malignancies. Women (n=1169) had an overall cancer SIR below unity and four LH malignancies versus 2.28 expected. Among the 7773 men, those first employed before 1950 had no overall cancer excess, a significant 1.4-fold increase in overall LH malignancies (43 observed versus 30.78 expected), and four CLL cases versus 3.27 expected. Findings for men first employed after 1950 are based on fewer cases, but there was no indication of excesses of overall cancer or LH malignancy. Numbers were too small in the group first employed after 1950 for meaningful analysis of LH malignancy subtypes such as CLL (one case).

CONCLUSION

These findings do not suggest a continuing excess of CLL but do suggest a small increase in incidence of overall LH malignancy for workers first employed before 1950. This may reflect associations with earlier workplace conditions, although work related patterns are mixed. Interpretation is limited by the diverse group of diseases within LH malignancies, and the lack of control for non-work factors other than sex, age, race, and period of diagnosis. This study has a major advantage of more complete and reliable cancer ascertainment compared with the mortality investigation, and shows the feasibility and benefits of using cancer registry incidence data in an occupational cohort study.

A retrospective mortality study of workers in three major U.S. refineries and chemical plants. Part II: Internal comparisons by geographic site, occupation, and smoking history

A cohort of 21,698 U.S. refinery and chemical plant workers was observed for eight years to determine if there were interplant or other variations in causes of mortality. Plant populations in three geographic locations were combined to develop an internal standard for comparing subgroups within the total cohort. At no one geographic site were consistently different rates for all major causes of death observed. The adjusted mortality rates for potentially exposed workers were slightly greater than those for nonexposed workers for most causes examined. Smokers incurred a higher risk of mortality from many causes of death when compared with nonsmokers, regardless of occupational category. After controlling for smoking, there remained a slight excess in mortality for potentially exposed as compared with nonexposed workers.

A retrospective mortality study of workers in three major U.S. refineries and chemical plants. Part 1: Comparisons with U.S. population

A dynamic retrospective cohort study was performed to examine the mortality experience of 21,698 workers at Exxon's refineries and chemical plants in Baton Rouge, La.; Baytown, Tex.; and Bayway/Bayonne, N.J. Included were 15,437 regular employees who worked at least one month during the period Jan. 1, 1970, through Dec. 31, 1977, and 6,261 retirees who were alive as of Jan. 1, 1970. There were 137,702 person-years of observation. Mortality in this total study population was generally lower than that of the U.S. population. Study follow-up was complete for 98.7% of the study population. The standardized mortality ratio for the 3,198 deaths was 91, while that for deaths from all cancers (N = 666) was 94. Certain slightly elevated disease-specific mortality ratios, although not statistically significant, could be of biological importance and merit further review.