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Letters to the Editor
We Respond:We asked Nanette O'Hara, public outreach coordinator for the Tampa Bay Estuary Program to respond: Mr. Womack: Our study will help to determine whether, and to what extent, the fertilizer bans are working. It is our assumption that communities which have a sales ban in place will show a greater reduction in nitrogen; our study is designed to test that hypothesis by measuring nitrogen levels in communities with different fertilizer ordinances (i.e. Hillsborough versus Pinellas). 1. Regarding nitrogen in reclaimed water, the amount varies according to the utility. But, overall, most reclaimed water in our area is not treated as thoroughly as wastewater that is directly discharged to the bay. The City of Tampa's wastewater, for example, is treated to advanced standards which remove more than 96% of the nitrogen prior to discharge to the bay. The City of St. Petersburg's wastewater, which is largely reclaimed for use on golf courses, medians, commercial properties and residential lawns, contains much more nitrogen. By our estimates, a homeowner irrigating twice a week with 0.75 inches of reclaimed water from St. Pete per irrigation would not need to apply any fertilizer at all to the lawn, per IFAS fertilization guidelines. The requirements for direct discharge of wastewater to the bay are much more stringent than those for wastewater that is reused for irrigation. 2. Our estimates indicate that nitrogen from urban fertilizer use comprises about 20% of the nitrogen carried in stormwater runoff to the bay. This is an extremely conservative estimate. Urban fertilizer refers primarily to residential fertilizer (single-family homes, condos, and office/retail complexes). Most of the local governments use very little fertilizer; Pinellas does not fertilize any of its properties anymore, except for athletic fields. Even the Florida Department of Transportation has stopped fertilizing highway medians and shoulders. As far as benchmarks for residential usage of fertilizer, studies conducted in the Wekiva Basin and other areas indicate that fertilizer use is highest in deed-restricted communities and especially in deed-restricted communities served by professional lawn care companies. 3. Our study will help to determine whether, and to what extent, the fertilizer bans are working. It is our assumption that communities which have a sales ban in place will show a greater reduction in nitrogen; our study is designed to test that hypothesis by measuring nitrogen levels in communities with different fertilizer ordinances (i.e. Hillsborough versus Pinellas). After one full year of a use and sales ban in Pinellas County, I can tell you that the overwhelming majority of homeowners are complying. In order for them not to comply they would have to drive to another county to buy fertilizer, and studies conducted by IFAS indicate that people buy fertilizer from the closest available store, NOT one in another county. They simply can't buy fertilizer in Pinellas anymore that is not at least 50% slow-release nitrogen from October - May and 0% nitrogen from June - September. The retail stores are reporting no appreciable decline in sales of fertilizer, and they tell us that their customers are satisfied with the ordinance-compliant products they are offering. The list of compliant products continues to grow and Florida fertilizer companies have been very proactive about producing 50% slow-release N fertilizers and zero N fertilizers to meet demand. The majority of ordinance violations that were issued in Pinellas County (which enforces its ordinance very aggressively) were given to commercial fertilizer applicators. The most common violations were applying fertilizer right before or during a heavy rainfall, and leaving fertilizer granules on roadways and other impervious surfaces or blowing them into ponds or storm drains. However, I personally have worked with several lawn care companies that have been very supportive of the ordinance and pleased that BMP training is now required of all applicators in Florida. 4. Our study is indeed taking samples of nitrogen both in storm water ponds (in cross-sections of neighborhoods where the only source of nitrogen is lawn fertilizer) and in the receiving waters of the bay. We have tracked nitrogen loadings in Tampa Bay for close to two decades and have very good estimates on loads by bay segment as well as at smaller scales. For this study, we are especially interested in measuring nitrogen amounts at a very localized level (thus, storm water ponds) to ensure we are only measuring nitrogen from residential fertilizer and not from any other sources. Because storm water ponds within the bay watershed ultimately drain to the bay, then logically less nitrogen going into those ponds means less nitrogen going to the bay. But, yes, we are monitoring both the ponds themselves and the nearest bay waters they drain to. Our research may not give us all the answers to all the questions, but it will be the first real effort to scientifically quantify and compare the effectiveness of fertilizer ordinances. We know many people are awaiting the outcome of our research.
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