Nurturing a Waterways Threat

by Kieran Mulvaney

Originally published in the Raleigh, NC News & Observer on 9/9/97.

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A microscopic organism smaller than the period at the end of this sentence has been tabbed by scientists and Maryland state officials as the killer of tens of thousands of fish in that state's Pocomoke River last month.

Responsible for similar fish kills in North Carolina, Pfiesteria piscicida - known by some as the "cell from hell" - emits a toxin so potent that minuscule amounts have reportedly caused nausea and memory loss, and have weakened the immune systems in people who have come into contact with it.

What has happened in the Pocomoke is the latest development in an ongoing saga. Pfiesteria lies dormant in many of this region's waterways, and unless lessons about what makes it flourish are learned, there could be many other outbreaks throughout Maryland's Eastern Shore and far beyond.

Ever since she and her colleagues at N.C. State University first identified the organism, Dr. JoAnn Burkholder has been trying to draw attention to the fact that pfiesteria thrives in waters laden with nutrient pollution - for example, around sewage outfalls. She argued that unless serious pollution prevention measures were taken, pfiesteria would undergo increasingly frequent periodic population explosions, killing millions of fish and posing a serious human health threat.

Few wanted to listen, but in 1995 that prediction came to fruition. Torrential rainfall washed massive amounts of effluent from hog farms into some of North Carolina's rivers and estuaries, resulting in pfiesteria blooms, huge fish kills and reports of serious illness from many who lived and worked by the water. Even then, some officials continued to dismiss and debunk Burkholder's work.

In comparison, and despite what at times appeared an almost painful reluctance to accept the obvious and admit that pfiesteria was at large in the Pocomoke, Maryland officials have responded with lightning speed to try and address the problem. The fish kill came just days after the state convened a meeting of scientists - including Burkholder - to review the evidence for pfiesteria's involvement in killing fish in the area and to propose solutions.

But in the same way that interest in North Carolina focused on the New, Neuse and Pamlico River estuaries - where pfiesteria struck the hardest - so attention in Maryland has rarely moved beyond the Pocomoke to the broader issues raised by the organism's emergence.

Pfiesteria's presence in the region is not confined to the short stretch of the Pocomoke that was closed following the fish kill. It has been found up and down the Eastern seaboard, from Delaware Bay south to the Gulf of Mexico.

In many coastal rivers and estuaries it is lurking quietly in the sediment, curled up in its harmless cyst form. But, fed enough nutrients, it could turn into its fish-killing form at any time. In recent days, scientists in Florida have identified pfiesteria in the St. John's River, where dead fish have been found covered with lesions.

Unfortunately, nutrient pollution is widespread and growing. Agriculture and animal husbandry, lawn care chemicals, household cleaning products, automobile exhaust and coal-burning power plants all contain or produce nutrient-rich compounds which find their way into our rivers and estuaries, and from there to coastal waters.

Numerous estuaries now receive levels of nitrates 1,000 times greater than a heavily fertilized agricultural field. Nutrient pollution is considered an important contributor to the growth in harmful algal blooms plaguing coastal environments; such blooms have been implicated in the deaths of manatees in Florida, the closure of shellfish beds in Louisiana and the development of "dead zones," areas up to several hundred miles square where all marine life is killed off. Pfiesteria is just the latest and most dramatic symptom of a major problem.

As hog wastes may be largely to blame for creating a nutrient-rich environment for pfiesteria in North Carolina, so attention on the Maryland's Eastern Shore has focused on the poultry industry and the possibility that phosphorous-rich chicken manure has washed into the river. Given the relative lack of industry and small population in the area, it seems a reasonable target of suspicion.

But elsewhere, hog waste or poultry farms may not be necessary to bring pfiesteria to life. We all contribute to nutrient pollution, and we can all play a role in reducing it. We don't have to use fertilizers on lawns. We can choose phosphate-free detergents. Even driving less can help, by reducing tailpipe pollution. Industry, too, can eliminate production methods that result in nitrogen emissions.

All these steps can help. And all may be necessary if we are to prevent recent events in the Pocomoke from being a curtain-raiser to a more widespread emergence of the "cell from hell."