In 30 minutes, the fluorometer rises to 2.45. Nothing to get excited about: When the half cup of fluorescent magenta dye -- poured into the Pomperaug two miles upstream and two hours earlier -- flowed past the previous monitoring station, the reading peaked at just over 4 ppb. "Uh-oh," says Raquel when she takes the next reading. "We're down to 2.301." In another five minutes it is 2.25.
"I guess that was the peak," says Dan, his voice the opposite of a peak, as he clambers out of the streambed. He and Raquel pack up their bottles and log books, the fluorometer, a tape measure, and a flow meter (basically a pair of spinning blades on a stick, used to measure the water's velocity), then drive downstream to do it all again with the boss, at the last of four monitoring stations.
The boss is Allison MacKay, an environmental engineer who specializes in aquatic chemistry at the University of Connecticut. MacKay had risen at four o'clock in the morning and loaded her car with gear, plus the sleepy Dan and Raquel, then drove west to Southbury. By eight, she had poured her dye into the Pomperaug at the point where it receives the Heritage Village effluent. (Invisible to the naked eye, the dye is nontoxic and will degrade in sunlight over three days.) With her grad students MacKay is tracking the dye's progress down a six-mile stretch. The concentration of the dye, read by the fluorometer, will tell her both the rate at which the Pomperaug flows and the rate at which a particular contaminant is diluted as it flows downstream -- two useful bits of information when you're studying the movement of contaminants from a single source. MacKay and her helpers are also taking water samples that will later be analyzed for the presence of the same 82 organic contaminants originally assayed by the USGS.
In a turquoise parka and insulated pants, MacKay kneels on the sandy bank. Her cheeks are pink in the cold air. If there is any fun to be had along a New England river in November, this crew refuses to acknowledge it. There are no observations on flora or fauna, no chitchat, no stone skipping or stick building. MacKay is all business, and her students follow her lead. For eight hours (no lunch break) they collect water and measure the river's depth, width, and velocity.
"The USGS does grab samples," says MacKay, rapidly punching a series of numbers into her calculator and plotting points on a hand-drawn graph. Grab samples are like snapshots, a single moment in a single place in a stream. "Their studies established the presence of drugs in our waterways, but no one in this country has looked at the temporal and spatial distribution or the environmental degradation rates of pharmaceuticals in surface water. That's what I'm doing." Among the factors that influence the compounds' fate are sunlight, temperature, flow rate, microorganisms in the sediment, minerals, and other chemicals in the water. If concentrations of any particular contaminant decrease, MacKay explains, she'll set up controlled lab experiments to see where, when, and how it happened: Was it the sun degrading the compound, a change in temperature, or an organism that might have consumed it? If aquatic life is suffering, she continues, researchers will need to know what concentrations they're being exposed to at different points in the stream.
This stretch of the Pomperaug makes an ideal laboratory for MacKay's study: It is wadeable, and it has only one significant input of both water and prescription compounds -- the Heritage Village treatment plant. The river is also a paradigm of the nation's threatened waterways, of the large- and small-scale changes that our growing population has wrought. Still, to drive the country roads of Southbury and its neighboring villages is to marvel at what hasn't changed in the past 200 years. Well-kept colonial houses still flank water mills; nineteenth-century farm fences decorously sag. The stream banks are, for the most part, intact. Trout congregate in deep pools. Though some of its meanders and oxbows were mechanically straightened more than half a century ago, the river still flows past horse farms and hemlock glades and rolling hills.
One can't help thinking the Pomperaug is privileged to run through a stronghold of the well-to-do. All American rivers are, at some level, endangered, but this one's remaining virtues are particularly obvious. Not only is there plenty worth saving here, there are also plenty of stakeholders eager to do the saving, among them a mild-mannered, semiretired internist named Marc Taylor, who happens to live just a few miles downstream from MacKay's sampling sites.
Taylor is the medical director of the River Glen Health Care Center, where Patricia Reilly lives, but he spends an inordinate amount of time fretting -- in public meetings and in private telephone calls with scientists, politicians, city planners, and conservation groups -- about the health of his river. "I'm concerned about pharmaceuticals in the river because I am a doctor," says Taylor, who speaks in precisely measured sentences, "and because I know these drugs are bioactive." That is, they can enter the bioprocesses of aquatic organisms.
As chairman of the Pomperaug River Watershed Coalition, Taylor has watched with increasing concern as developers cut streets into nearby hillsides, shopping centers supplant farms and orchards, and waves of the elderly flock to four planned communities within the town limits. "As the population of the watershed goes up," says Taylor, sitting in his basement office surrounded by maps of the region, "more groundwater is being pumped. We've got three public water companies drawing water from wells sunk near the Pomperaug." With a few computer keystrokes, Taylor pulls up real-time data from a gauging station on the river. This afternoon's flow is 250 cubic feet per second. Last summer it dropped to 8 cubic feet per second -- one of the lowest flow rates in the river's recorded history. Some small streams in the Pomperaug watershed now completely disappear in the summer.
