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The discharge of creosote and pentachlorophenol wastewaters to unlined surface impoundments has resulted in groundwater contamination in the vicinity of a wood-treatment plant near Pensacola, Florida. Total phenol concentrations of 36,000 micrograms per liter have been detected at a depth 40 feet below land surface in a test hole 100 feet south of the overflow impoundment. Phenol concentrations in this same test hole were less than 10 micrograms per liter at a depth of 90 feet below land surface. Samples collected in test holes 1,350 feet downgradient from the surface impoundments and 100 feet north of Pensacola Bay, above and immediately below a clay lens, indicate that phenol contaminated ground water may not be discharging directly into Pensacola Bay. Phenol concentrations exceeding 20 micrograms per liter were detected in samples from a drainage ditch discharging directly into Bayou Chico. Microbiological data collected near the wood-treatment site suggest that an anaerobic methanogenic ecosystem contributes to a reduction in phenol concentrations in ground water. A laboratory study using bacteria isolated from the study site indicates that phenol, 2-methylphenol, and 3-methylphenol are significantly degraded and that methanogenesis reduces total phenol concentrations in laboratory digesters by 45 percent. Pentachlorophenol may inhibit methanogenesis at concentrations exceeding 0.45 milligrams per liter.

Results of a 1983-84 reconnaissance of 15 municipal wastewater treatment plants in Florida indicated that effluent from most of the plants contains trace concentrations of volatile organic compounds. Chloroform was detected in the effluent at 11 of the 15 plants and its common occurrence was likely the result of chlorination. The maximum concentration of chloroform detected in the effluent sampled was 120 micrograms per liter. Detectable concentrations of selected organophosphorus insecticides were also common. For example, diazinon was detected in the effluent at 12 of the 15 plants with a maximum concentration of 1.5 micrograms per liter. Organochlorine insecticides, primarily lindane, were detected in the effluent at 8 of the 15 plants with a maximum concentration of 1.0 micrograms per liter. Volatile compounds, primarily chloroform, were detected in water from monitor wells at four plants and organophosphorus insecticides, primarily diazinon, were present in the ground water at three treatment plants. Organochlorine insecticides were not detected in any samples from monitor wells. Based on the limited data available, this cursory reconnaissance suggests that the organic contaminants commonly occurring in the effluent of many of the treatment plants are not transported into the local ground water.

Water samples from two Hudson River floods in 1977-one originating mainly in shale subbasins that produce high sediment loads, the other in soil-poor, crystalline rock terrane that yields little sediment-were analyzed to evaluate the relationship of iron, manganese, lead, phosphorus, and polychlorinated biphenyls (PCB's) to suspended-sediment concentration. During the flood of high sediment discharge, ratios for all substances studied except PCB's reflected their concentration within the basin regolith. During the flood of smaller magnitude, from the low-sediment crystalline terrane, however, only the ratio for iron correlated with predicted concentrations in the basin, which suggests that the chemical constituents studied were contributed principally from other sources, possibly anthropogenic sources. High lead concentrations in the low-sediment flood were derived from an unidentified, basinwide source whose contribution was relatively insignificant during the flood from the shale area.

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