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Pesticides and Fuels Twenty-eight floodwater sam- ples were analyzed for 47 different pesticide compounds by using a broad-spectrum, low-level, solid-phase extraction and gas chromatography/mass spectropho- tometry analytical method (Zaugg and others, 1995). Minimum detec- tion levels for these compounds vary. Of the 47 pesticide com- pounds, 17 were found in very low but detectable concentrations ranging from 0.4 to 102 nanograms per liter (ng/L) (table 9). The maXl- mum detected concentration was metolachlor in the Neuse River at Smithfield (site 23). Metolachlor, atrazine, and prometon-all herbicides-were the pesticides most commonly detected. Meto- lac hI or was detected in every sample, atrazine in 25 samples, and prometon in 24 samples. Meto- lachlor, carbaryl (an insecticide used on lawns, fruittrees, and pets), malathion (an insecticide used to control insects on fruits, vegetables, and animals), and diazinon (a resi- dential insccticide) were detected in thc grcatest concentrations. The largest number of pesticides were detected in Contcntnea Creek (SIte 3 I), which is a predominantly agri- cultural basin; 13 pesticides were detected at site 3 I. A total of 12 pes- ticide compounds were detected in the Neuse River near Fort Barnwell (site 32). The fewest pesticide com- pounds were detected in the Tar River near Tar River, where only metolachlor was detected, and the Lumber River where only meto- lachlor and atrazine were detected. The highest concentrations of diazinon (an insecticide used to treat lawns and for pest control) was WATERBORNE PATHOGENS Waterborne pathogens are bacteria, viruses, and protozoans that cause diseases in humans and are transmitted by drinking or exposure to contaminated water, Waterborne pathogens are found in nearly all surface-water systems, as well as in many ground-water systems, and gener- ally originate from body fluids and feces of humans and animals. Contamination of surface waters by fecal material is a special con- cern during floods because of failed wastewater-treatment plants, septic systems, and animal waste lagoons. Additional contam- ination may result where flood- waters innundate vast areas of land that may be contaminated by fecal material from wildlife, live- stock, or wastewater spray irriga- tion systems. The presence of certain types of bacteria are used as indicators of fecal contamination. Water-quality regulations regard- ing fecal contamination of surface waters in North Carolina are based on the presence of fecal coliform bacteria, which mayor may not be of fecal origin. The presence of a specific fecal coliform bacterium, Escherichia coli, is direct evidence of fecal contamination. Another type of bacterial indicator of fecal. contamination is fecal streptococcI. Enterococci, which is a type of fecal streptococci, is a more spe- cific indicator of contamination than fecal streptococci. Clostridium perfringens is an enteric bacterium that forms a spore which is more tolerant to environmental conditions than other traditional indicators of fecal contamination. C. perfringens is primarily associated with human waste and is resistant to the chlo- rination process used to disinfect treated wastewater immediately prior to discharge. Consequently, C. perfringens is a useful indica- tor of fecal contamination from point sources, There are more than 100 types of human waterborne viruses. Bacteriophages (or phages) are viruses that infect bacteria and are present wher- ever coliform bacteria are present. A coliphage is a virus that specifically infects and replicates in E. coli bacteria; coliphage is considered to be representative of the transport and survival of viruses in the environment. Bacteriodes fragilis phage has been found only in human feces, is unable to multi- ply in the environment, and is a promising indicator of human fecal pollution. The two most common protozoans implicated in out- breaks of waterborne diseases are Cryptosporidium and Giardia lambia. Cryptosporidium is a parasite that infects many wild and domestic animals, as well as humans, and is highly resistant to disinfectants used to purify drinking water. Giardia is a one-celled, microscopic parasite that lives in the intestines of peo- ple and animals. During the past 15 years, Giardia has become recognized as one of the most common causes of waterborne disease in humans in the United States. This parasite is found in every region of the United States and throughout the world, and is moderately resistant to disinfectants. Two Nlonths of Flooding in Eastern North Carolina. Septembcr-October 1999