Berkeley Pit Lake

Jonas, J.P. and Gammons, C.H. (2000) Iron cycling in the Berkeley Pit-lake, Butte, Montana. Abstracts with Programs. The Geological Society of America, 32(5), 13. 

Figure 8.8. Location and depth contours of the Berkeley Pit Lake.

Figure 8.9. / I I of the Berkeley Pit lake as a result of the mixing with an alkaline tailings fluid.

This is no ordinary lake, however, and its microbial inhabitants reflect the unique nature of the lake. Berkeley Pit Lake is located in Butte, Montana, called the richest hill on earth because of the high quality ore bodies that concentrated in this area. While scientists and engineers attempted to remediate the Pit Lake, we initiated a different type of mining venture— mining for microbes. Over the last eight years, we have isolated and studied over 60 fungi and bacteria from the surface waters down to the lake bottom sediments at 720 feet. Last year we were able to access deep Pit Lake sediments as well and have isolated several new microbes not found in the water column. 

To isolate and identify culturable microorganisms from Berkeley Pit lake water and sediment samples. 

Berkeley Pit Lake is our extreme environment. We are confining our studies to microbial life in the Pit for the simple reason that microbes are the predominant, and perhaps sole inhabitants of this toxic lake. Unlike most rivers and lakes in Montana, Berkeley Pit Lake does not harbor trout, grayling or other blue ribbon fish species. Aside from a single water bug photographed resting on the surface of the Pit Lake, and a flock of snow geese that landed on the water and subsequently died, no evidence of macrobial life exists. 

The Berkeley Pit evolved from an open-pit copper mine to an acid mine waste lake in less than twenty years. There are actually many acid lakes worldwide. Some are volcanic crater lakes and include Lake Tiwo Nua Muri Koohi Fah in Flores, Indonesia Crater Lake in Ruahepu. New Zealand Yugama Lake in Japan and Laguna Caliente in Costa Rica. Acid mine pit lakes like the Berkeley Pit Lake and the Phelps Dodge Tyrone Mine in New Mexico owe their existence to anthropogenic activities. 

Scientists at the Montana Bureau of Mines and Geology have conducted much of the characterization of the Berkeley Pit. According to their studies, the shallow water of the Pit Lake - the epilimnion - is separated from the deep water - the hypolimnion — by a chemocline, a zone of rapid chemical and physical change. In Berkeley Pit Lake, the chemocline is between 35 to 50 feet below the lake surface. The epilimnion is characterized by a pH of 2.5 and a temperature of 0°C in winter (ice forms on the surface) to 25°C in summer. Dissolved-metal concentrations in the epilimnion include Cu, 140 mg/L and Zn, 540 mg/L. The hypolimnion is characterized by a pH of 2.5 and an annual temperature of 4.5 °C. Dissolved-metal concentrations in the hypolimnion include Cu, 190 mg/L and Zn, 620 mg/L. Iron(II) Iron(III) ratio in the hypolimnion is 2.5 and in the epilimnion 0.36 [47]. 

The discovery of a relatively rich microbial flora in the rising waters of the Berkeley Pit has provided a new arena for chemical investigation. Until now, the primary concern has been effective remediation of this enormous Superfund site. Ground and surface waters that percolate through Berkeley Pit Lake ultimately enter the... 

Clark Fork River, an important tributary of the Columbia River. Acid mine drainage seriously degrades water quality and threatens the existence of animal and plant populations. The average pH is 2.5, an acidity level toxic to most life forms, both macrobial and microbial. Many cations reach levels well above drinking water standards set by the EPA. A sample of Berkeley Pit lake water analyzed by Inductively Coupled Plasma (ICP) has high levels of Fe+2/Fe+3, Al+, Cu+2, and many other cations. It is also very rich in sulfates, the predominant anionic species present (8500 ppm). Some typical cation levels in Pit water (24) and EPA drinking water standards for these same cations are shown below in Table 1 [48],... 

Table 1. Metal cation levels in Berkeley Pit Lake compared to drinking water standards...

Endophytic microorganisms are not the only neglected population for natural products investigations. Extreme environments have been all but overlooked in drug discovery ventures. Yet clearly these unique environments support unique microbial life. Our attempts to isolate microorganisms from different depths of Berkeley Pit Lake have yielded over sixty culturable, aerobic fungi and bacteria. Microbial secondary metabolites are particularly desirable for the following reasons ... 

Signal transduction enzyme inhibition assays guided the isolation of two novel hybrid polyketide-terpenoid metabolites from a Penicillium sp. growing in the deepest waters (>750 ft) of Berkeley Pit Lake [9], Their structures were deduced by spectroscopic analysis and confirmed by single crystal x-ray analysis on berkeleydione (13). Both compounds inhibited signal transduction enzymes caspase-1 and matrix metalloproteinase-3. Berkeleydione (13) was also active against non-small cell lung cancer in NCI s 60 cell line anti-tumor screen. 

The crude organic extracts of a Penicillium sp. isolated from a depth of 885 ft. were active against Staphylococcus aureus and in the brine shrimp lethality screen. These extracts were further tested using enzyme inhibition assays for two different signal transduction enzymes - matrix metalloproteinase-3 (MMP-3) and caspase-1 (Casp-1). Compounds 13 and 14 were isolated from the chloroform extracts of the broth filtrate of a Penicillium sp. found growing in Berkeley Pit Lake. Berkeleydione (13, 5.5 mg/L) was isolated as a crystalline... 

Mitman, G. G., 1999. A Final Report Biological Survey of the Berkeley Pit Lake System. Mine Waste Technology Program Activity IV, Project 10. USEPA National Risk Management Lab, IAG ID DW89938513-01-0. 

FIGURE 1 Berkeley Pit Lake in Butte (Montana, US) and structure of (—)-berkelic acid. 

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