Question
My neighbor put Compro (sewer sludge) on his lawn this week. He tells me that it has helped to amend the soil pH and helps to bring up really nice grass in the Spring. The only bad thing is it smells really bad. He also puts it as a top dressing on his flower beds. His lawn does look nice, I'm thinking of doing this too. Is Compro considered organic? And is it similar to leafgrow? Also, I have a dog, can the bacteria from the compro hurt my dog? Thanks.

By the way, can I lime at the same time I put down the Compro?

Answer
'Compro' is one of those things you either love or hate.

This dried sewage sludge residue is imported from Washington, DC and Baltimore, MD, for processing.  Treatment includes blending with wood chips, pasteurizing and curing the results.

A New Bay Times Apr. 14, 1999 essay titled 'Down the Drain? Gardeners Love Compro; Foes Say It Stinks' by San Francisco writer Mary Catherine Ball points to a list of impressive Compro customers.  'Critically acclaimed Compro renovated the South Lawn of the White House and the Lawns of Washington's monuments, the State House in Annapolis and Mount Vernon.'

That's not all.  Ball adds, 'The grounds at Camden Yards, Jack Kent Cooke Stadium, the United States Naval Academy Baseball Stadium and BaySox Stadium are also nourished by Compro.'

But as we know, there is a downside here.  As Ball reported, 'Now Compro is in trouble for stinking.'  Those who live in the vicinity of its Silver Spring, MD composting facility -- mind you, no one lived there when it was first built 40 years ago -- have had it up to hear with the smell.

Here's the URL:

www.bayweekly.com/year99/issue7_14/dock7_14.html

Anyway, that's the deal with ComPRO.  There is an odor, and it is truly offensive to some people while others are not bothered by it.  They did stop making it for a while because so many people complained.  That was followed by more complaints that it was no longer available.  So they started up again, with some modifications to the formula, and produced a Biosolids fertilizer designed just for Turfgrass.  They announced it thusly: 'We are confident that you will be delighted with this product.'

And people are. The Maryland Environmental Service continues to do a thriving business in new, improved ComPRO as well as the 'Leafgro' you mention, a compost made from dead leaves and grass clippings:

www.menv.com/content/products/compro.htm

Have you ever sprayed a plot with Fish Emulsion?  That stuff stinks to high heaven even AFTER it's deodorized, but if you get used to it, you don't care.  No matter what this stuff smells like, there are still health questions that are not yet definitively answered.  It's the same questions people ask about ALL Sewage Sludge fertilizer products.  In one place, it's 'Milorganite' -- Milwaukee Organic Nitrogen, sold by the Milwaukee, Wisconsin, Metropolitan Sewage District.  And 'Bay State Fertilizer', produced by the Massachusetts Water Resources Authority.  The biggest issue is over heavy metals.

You should understand that all fertilizers contain heavy metals.  Some are necessary for human or plant health -- Zinc, Iron, Cobalt, Copper, Molybdenum, Manganese and others.

The concern is that these biosolids may have un-healthy, perhaps toxic amounts of pollutants.  Milorganite boasts that it is touted for 'Exceptional Quality' by the U.S. EPA.  Lots of fertilizers on the market don't qualify.  Milorganite, though, can be used on all types of Grass, Trees, shrubs, flowers and vegetable gardens.

Over the past few decades, heavy metal contamination has been a serious issue.  Communities designated as Superfund Sites -- Kellogg, Idaho, which runs a smelter operation; Leadville, Colorado, a mining town; and Palmerton, Pennsylvania -- and Boston, Maryland and Cincinnati were tested and analyzed.

Zinc levels in the hillsides of Palmerton, caused by 80 years of Zinc smelting, were so high, vast sections of the forest were completely defoliated, followed by severe erosion of topsoil.  Microbes vanished from Soil due to heavy metal contamination; as a result, Trees that had been dead for 20 years could not decompose.

Studies also looked at Lead -- 'Pb' in science shorthand.  One you can read is a 1994 presentation by Rufus Chaney, USDA-ARS, 'Soil science issues and bioavailability', delivered during the Palmerton Superfund Site Symposium 1994.  He described numerous investigations into high levels of Lead and Zinc detected in Soil around the world.  One question they had was, Does lead contamination in Soil affect children?

In Bowmanstown, PA, in 1980, a smelter was blamed for lead contamination.  Soil near house foundations showed alarming lead levels, traced to roof runoff of lead from the atmosphere and the flaking of old lead housepaints.

In England, children in two different communities were checked for lead.  Soil in one area, Thornton, was heavily contaminated with lead.  Yet the children in Thornton tested LOWER for lead than the children in another area, Birmingham, where lead was not excessive.

In Aspen, Colorado, Soils in some regions have been found with high lead.  But blood tests of the children of Aspen show their levels remain low.

Further studies may have figured out why.

Children who eat regular meals are able to block absorption of Lead.  In several cases, those who lived smack in the center of chemical hotspots had minimally elevated Lead blood levels.  Children who ate only once a day, usually from low income households, could not ward off a Lead rush because their stomaches did not have Lead-absorbing Phytate, Fiber, Calcium and other minerals.  But the lead levels in their Soils were soaring.

Cadmium and Zinc levels measured in Alfalfa from contaminated Soil at one site were surprisingly low.  Turns out the Soil was too alkaline for much of these metals to be absorbed.  Farmers fertilized and limed to elevate the pH.  Homegrown Radishes grown in Soil across the street from one smelter had been turning Chlorotic for years due to the heavy metal levels in the Soil.  Those who raised livestock added Copper to their diet to block the toxic heavy metals from being absorbed.  

How then do Biosolids-based amendments affect Soil, heavy metal levels, and the plants or vegetables you grow at home?

As you can see, this is not as clear as we'd like.  But there are several things we do know.

One, there's less Lead to worry about in Sludge fertilizers on the market, because there's a lot less Lead in the Sludge.  Un-leaded gas.  Un-leaded paint.  Cans from the supermarket no longer contain lead.  The Sludge used to make these fertilizers are practically lead-free.  And because they are processed to remove Chromium, there's none of that, either.

Two, the laws of Soil chemistry TRAP toxic metals onto Soil particles.  Organic matter in Soil glues them down and high levels of Iron controls bioavailability.  This is one reason biosolids are used in Superfund Soil detox projects:  

www.nic.edu/library/superfund/refdocs/cda0134.pdf

The MWRA lists the heavy metals that are (or aren't) in its Bay State Fertilizer:

www.mwra.state.ma.us/publications/fertilizerbrochure.pdf

Boron.  Copper.  Molybdenum.  Nickel.  Zinc.  Arsenic.  Chromium.  Cadmium.  Lead.  Mercury.  Selenium.  Note these products are sterilized to destroy pathogens during processing, so there's no concern about catching any weird diseases from them.

Is it Organic?

That depends on which state you're growing in.  Fertilizer labels are regulated by state officials, who themselves are members of the Association of American Plant Food Control Officials (aka 'AAPFCO').  And AAPFCO permits them to call their fertilizers 'Organic' even when they contain Urea and Sewage biosolids.  NONE of these are permitted by the National Organic Program (NOP).  Many Organic Gardeners would disqualify a product that is made of Urea or Sewage.  And while the NOP signs off on Compost, it forbids use of Sewage Sludge, or any Biosolids for that matter, or Urea.

Still, there's that matter of the smell.

Gardening rumors held that the odor of Milorganite qualified it as n effective Deer repellent.  Cornell University gave it a try:

cwmi.css.cornell.edu/milorganite.pdf

The very aroma that turns off Deer may turn your Dog on.  If your Dog should eat any, it's way less unhealthy than some of the other things s/he probably ingests during the week.  I use one of these on my Lawn; it contains none of the chemical Salts that concentrated products have, and I think it's good to use a variety of amendments.  The odor subsides with time and exposure to the elements.  But I also monitor research activity.  You never know.

THE LONG ISLAND GARDENER