PCBs, Pollution and Detoxification

Discovery and Initial Response

Early in 1983, sporadic reports of disfigured and dwarfed fish with skin ulcers and tumors, odorous oil slicks in the river, and deformed plants and fruits in the factory yard (Figure 1) were dismissed as "coincidental" occurrences. At the same time, geological preparations for a new water supply disclosed a dump site situated above the proposed water source, this source having been intended to provide sufficient and affordable water to the region through the turn of the century. Greasy, oil-soaked limestone was found to extend well beneath the water table. Public concern over possible long-term health effects due to PCBs absorbed from this water prompted authorities in 1984 to terminate work on the new water system, to start a new project to supply water from distant sources, and to initiate environmental and cross-sectional health surveys.

Eight major dump sites were located. By determining airborne PCB levels, as recovered from pine tree needles, and PCB levels in the downstream river sediment, it was estimated that contamination had spread over some 50 square kilometers, potentially exposing at least 3,000 residents. PCB contents were measured in various fish species along the river (Table 1). The PCB content in one 4year-old trout, measured at 116 mg/Kg (the FDA tolerance limit is 2 mg/Kg), is among the highest reported in the world. The highest river water PCB content, taken in summer 1983, was 600 nanograms/liter (ng/L) at the artesian source of the river, some 4 Km from the plant. This exceeds by 600 fold the US EPA limit of I ng/L for drinking water. The corresponding stream flow rate was 800 L/sec. On a dry weight basis, river sediments at the source contained up to 55 mg/Kg of PCBS. (Brumen et al., 1984; Herlander, 1986; Jugovic, 1987).

Due to the region's karstic limestone geological structure and resultant lack of surface water, residents distant from the river depended on rain water as their main source for drinking. Water was collected from roofs into hand-dug cisterns. The PCB content in the water of these cisterns was 3 to 4 times that permitted by the US EPA. After the cisterns were scrubbed with 70-80 percent ethanol, the PCB content was reduced to the I ng/L level. (Heriander, 1986) As a consequence of the widespread contamination, water was supplied to the inhabitants by tank-trucks until 1988, when a new pipeline brought fresh, clean water from a source 80 kilometers (50 miles) distant. (Pucelj, 1987)

In the food chain, milk, eggs, pork, beef, and poultry were found to contain high amounts of PCBs (Table 1). A 1984 order mandating slaughter of these animals was met with reluctance, and their subsequent confiscation with only partial reimbursement caused public outcry. It took more than a year to settle disputes and remedy the damage caused by these actions. The use of contaminated waters for fishing, bathing, drinking, and watering was banned, and private mills and water-powered saws were shut down in 1984. The financial losses to the owners, resulting from these restrictions, were not reimbursed.

At the impregnating hall, PCB air concentrations exceeded by up to 5.2 times the 8 hour MPC (Maximal Permissive Concentration) of I mg/m3, and TCE levels were 1.6 times higher than the respective MPC of 250 Mg/m3 (ACGIH, 1986; Crnivec et al., 1986).

The factory stopped using PCBs in 1985, temporarily switched to castor oil, and subsequently used a Japanese product with the brand name "PXE" (Pucelj, 1987). Within a year, a double-walled concrete landfill of 300 m , with plastic wall lining and underground safety drains, was erected on the factory yard. The surface layers of the eight major dump sites were excavated to a depth of 60 cm (two ft.) and the material trucked to the landfill, along with other discarded products. This part of the clean-up was concluded in 1987.

Health Consequences

In 1984, the University of Ljubljana, Institute of Occupational, Traffic, and Sports Medicine, and the Committee of Public Health of the Republic of Slovenia initiated a two-year cross-sectional health assessment survey of 284 adults from six villages along the river and within 5 km of the factory. In addition to the 122 males and 162 females of this group, the study included all pregnant and breastfeeding women, and 60 children under 10 years of age from these villages. From the group of 284 adults, a random sample of 62 men and 55 women was selected for further evaluation. As a separate item, this study also evaluated the health status of 21 male workers from the factory impregnating halls (Crnivec et al., 1986).

The mean PCB serum level in residents was 52 micrograms/liter (ug/L), ranging from 5 to 132 ug/L, which is approximately ten times higher than the mean for an unexposed group in Slovenia. The average daily amount of PCBs absorbed by the residents was estimated to be 0.46 milligrams. This exceeds by up to 90 times the proposed action levels for an unexposed population (Crnivec et al., 1986; Landrigan, 1980).

No acute toxic effects, increased prevalence of cancers, or congenital birth defects were detected. However, biochemical abnormalities indicating carbohydrate intolerance and derangements in the metabolism of lipids were evident. Changes found in the histology and ultrastructure of liver biopsy samples obtained both from children and adults were consistent with other published cases of PCB exposure (Landrigan, 1980; Maroni et al., 1981; Nishizumi, 1970).

In accordance with the underlying political objectives leading to the construction of the factory, workers kept their jobs for prolonged periods. The average length of employment at the factory was ten years, and that of direct exposure to PCBs was eight years. The mean PCB level in serum was 430 ug/L, ranging from 22 to 2,200 ug/L (Table II). As found elsewhere (Brown and Jones, 1981; Buser, 1985; Chase et al., 1982; Maroni et al., 1981; Safe, 1984), the range of PCB levels was wide and increased in proportion to the length of employment.

No increased prevalence of cancers was found in these workers. This group did, however, have an enhanced number of cases reporting infertility (Harris et al., 1985). Acute exposures to PCBs were associated with an uncomfortable flu-like syndrome, chloracne eruptions, and, as elsewhere (Kimbrough, 1987; Safe, 1984), serum PCB levels of 1000 ug/L or more.

Biochemical abnormalities found in the workers included elevated enzyme levels ( alkaline pholspatase, serum aspartate aminotransferase, serum alanine aminotransferase and g-glutamic transferase) on "liver function tests", elevated serum lipids (LDL lipoproteins and triacylglycerols), and either carbohydrate intolerance or overt diabetes. Microscopic changes of liver structure were also found. These chemical and morphological changes were similar to those found in inadvertently exposed residents. In none of the groups under study did the abnormalities correlate with the PCB levels.

A pattern of nonspecific symptoms was noted in the majority of the examined persons. When prior medical evaluations were retrieved from several medical institutions, it was noted that the appearance of these symptoms had preceded public awareness of environmental contamination. The onset of complaints in residents, and especially workers, occurred several years before the health survey was initiated.

Clinical complaints reported by the cross-sectional survey as most frequent were diffuse headaches, loss of mental acuity, concentration disabilities, nervousness, sleep disturbances, eye problems (in particular conjunctivitis and light sensitivity), chloracne eruptions and skin rashes, chronic respiratory, gastrointestinal and neurological disturbances (as paresthesia and unexplained pains), joint pains and edematous swelling of the limbs (Table 11). Though present for some time, the self-rated severity of symptoms in individual patients fluctuated considerably over their history and symptom severity also varied between patients. Notable observations derived from this survey were that: (i) No spontaneous reMission of symptoms was reported and (ii) medical treatments directed to particular complaints did not alleviate the problems.

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