Journal of Toxicology & Environmental Health Part A: Current Issues

French, Alexandra Steiner

doi: 10.1080/009841099158024pmid: 10094244

In the past two decades, concern has been expressed over the potential carcinogenicity of disinfection by-products (DBPs) found in chlorinated drinking water. More recently, research efforts have expanded to include noncancer endpoints as well. The objective of the present studies was to evaluate the potential of bromodichloromethane (BDCM), one of the most prevalent DBPs, to adversely affect immune function in mice and rats following drinking water or gavage exposure. Antigen-specific immunity was assessed as the antibody response to sheep erythrocytes; responses to T-and B-cell mitogens were evaluated as a non-antigen-specific measure of the proliferative potential of splenic and mesenteric lymph node lymphocytes. In consideration of an exposure route relevant to humans, C57BL/6 mice received 0.05, 0.25, or 0.5 g BDCM/L and F344 rats received 0.07 or 0.7 g BDCM/L via drinking water. In order to evaluate the effects of higher doses, animals were administered 50, 125, or 250 mg BDCM/kg/d (mice) or 75, 150, or 300 mg BDCM/ kg/d (rats) via gavage. Under the conditions of these studies, no significant adverse effects on immune function were observed in mice. Despite some changes that were observed in non-antigen-specific immunity in rats, these experiments suggest that the immune system is not a sensitive target organ for BDCM toxicity.

Casey, Ann C.

doi: 10.1080/009841099158033pmid: 10094245

PCBs have been considered to be almost nonvolatile and insoluble in water. However, recent studies have shown the importance of their slight solubility in water and capability to enter the atmosphere and disperse throughout the global environment. This preliminary study was designed to measure uptake and observe any physiological changes in SpragueDawley rats. The PCB product Aroclor 1242 is the major pollutant of the Hudson River, NY, and New Bedford Harbor, MA. The rats were exposed for 30 d to 0.9 mug/m 3 via inhalation and 0.436 mug/g (ppm) in the food. The inhalation of PCBs gave a greater PCB uptake than ingestion. Both routes of administration caused significant serum thyroid hormone elevations. Histopathologic changes were observed in the urinary bladder, thymus, and the thyroid after both exposure regiments. Rearing and ambulation were significantly decreased in both exposure regiments in an open field behavior test.

Broeckaert, F.

doi: 10.1080/009841099158042pmid: 10094246

The objective of this study was to assess the effect of two arsenic-containing particles, coal fly ash (FA) and copper smelter dust (CU), on lung integrity and on the ex vivo release of tumor necrosis factor alpha (TNF- ) by alveolar phagocytes. Particle effects were compared in nonoverload condition on the basis of a low but identical volume load and arsenic content intratracheally instilled in the mouse lung (273 nl/mouse and 186 ng arsenic/mouse; FAL and CUL groups). Other mice received 600 ng arsenic/mouse in amounts of particles leading to different volume loads (FAH and CUH groups: 880 and 273 nl/mouse, respectively). Animals were sacrificed at 1, 6, 30, or 120 d (FAL and CUL groups) or at 6 and 120 d posttreatment (FAH and CUH groups). Biochemical markers and inflammatory cell number and type were analyzed in bronchoalveolar lavage, ex vivo TNF- production by alveolar phagocytes was assessed, and measurement of arsenic lung content and histopathological examinations were performed. Our results show that coal fly ash and copper smelter dust bear distinct inflammatory properties. At the end of the observation period (d 120), the high CU dose (CUH ) produced a fibrotic reaction whereas the high dose of FA particles (FAH ) generated a delayed and persistent lung inflammatory reaction associated with lymphoid noduli. Marked differences in TNFproduction were observed within the CU and FA groups. CU particles, conceivably through their metal content, decreased TNF-production by alveolar phagocytes. Due to their low arsenic content, considerably higher FA particle doses needed to be administered to produce an inhibition of TNF-production. Since high doses of FA (FAH) caused an overload condition, our results do not allow us to decide whether FA-mediated TNF reduction is due to the load administered or to the metallic content.

Yang, Chun-Yuh

doi: 10.1080/009841099158051pmid: 10094247

The possible association between the risk of pancreatic cancer mortality and hardness levels in drinking water from municipal supplies was investigated in a matched casecontrol study in Taiwan. All eligible pancreatic cancer deaths (883 cases) of Taiwan residents from 1990 through 1994 were compared with deaths from other causes (883 controls), and the hardness levels of the drinking water used by these residents were determined. Data on water hardness throughout Taiwan was collected from Taiwan Water Supply Corporation (TWSC). The control group consisted of people who died from other causes and were pair matched to the cancer cases by sex, year of birth, and year of death. The results show that there is a 39% excess risk of mortality from pancreatic cancer in relation to the use of soft water. Trend analyses showed an increasing odds ratio for pancreatic cancer with decreasing levels of hardness in drinking water. This is an important finding for the Taiwan water industry and human health.

doi: 10.1080/009841099158060pmid: N/A