I was at a program for Coastal Studies this weekend - run as part of Johns Hopkins CTY effort. Part program for kids, seminars for parents and a way for schools to get exposure. One presentation on the effects of Nitrogen on coastal marine envioronments was quite interesting.
You've probably heard, too much Nitrogen/fertilizer/waste runoff changes marine environments. "Active" Nitrogen is necessary for plants to grow but too much causes problems. Runoff into water leads to more algae, less grasses, eventually leading to large algae blooms, dieoffs and anoxic conditions where O2 levels are so depleted that no life can be supported in that area. A marine environment conducive to a wide variety of marine life - vital to some fisheries - is killed off and replaced with a far more "damaging" one when there is too much Nitrogen in the water. This is an issue in Long Island Sound, Chesapeake Bay and - new to me - a large area in the Gulf off the coast of LA. There is a HUGE "Dead Zone" resulting from the Mississippi run-off. You also see effects in ponds and lakes, and rivers. more....
This problem occurs when excess fertilizer, animal waste and human waste (TREATED and non-treated) is introduced into the environment. Excess Nitrogen - in an active (non bonded N2 gaseous form) was the problem discussed in the presentation I attended.
This is a relatively recent problem (in the last 50 years) due to the HUGE increases in fertilizer use after WWII. This occurred as a by-product of munitions production (ammonium nitrate) - hence the close relationship between fertilizer/explosives - nitrates.
The chemical industry is now able to produce large amounts of nitrates (in comparison to the use of animal waste or mining of guano - bird excrement deposits) for fertilizer, and increase food production there are other issues at work here.
Farmers tend to OVERUSE fertilizer - and the recommended levels are already high since companies wish to sell MORE fertilizer, not less. A 25% reduction of fertilizer use would reduce excess nitrates in the water substantially but have little effect on crop yields but the "better safe than sorry" attitude predominates.
Of course, under current regulations, farmers tend to OVERPRODUCE as well. So we have farmers who, in a distorted system, use too much fertilizer to produce too much product.....and are paid NOT to produce even more.
A rational approach would be to cut back fertilizer use in agriculture. You'd have lower costs and eventual pollution (in well water as well). But how do you do this? Picture the outrage if government tried to regulate this. The US doesn't want more food grown!!!!
The use of fertilizers in suburban areas is a touchy one but one than has a measurable effect. Lawns - and golf courses in particular - have a bvery real impact since overuse here is worse than on farms. Local communities have hit the "it's MY yard, I can do what I want" attitude adn legal defense when they have tried to regulate this.
Waste is another huge issue. Animal waste from chickens and pigs is a HUGE issue in the Chesapeake Bay area and te Carolinas. Leakage, breaks or overflows of waste ponds have caused huge damage. This waste is produced by industrial scale animalproduction and is a far larger issue than increasing nitrogen levels in water.
Human waste is another - and even larger - contributor of Nitrogen to waterways. Waste leaking from septic systems is an expected source but TREATED waste is an even larger issue. While cities treat human waste for bacteria, they do NOT "de-Nitrify" theis waste stream. It IS possible to treat this waste stream so that active Nitrogen is removed and turned back to N2, but this happens rarely. Few communities are aware of this issue and take any action on it. There are additional costs involved, nominal - a few dollars per year per person - and existing plants CAN be retrofitted to do thsi but there is little will to do so (and apparently no governmental requirements to do so). A few shore communities, looking to preserve their beaches have takens these measures but they are few and far between.
The current farming environment is geared towards petrochemical fertilizer use and production. The "system" in place produces more food than we use under normal conditions. We are "using up" farmland under current production techniques.
A reduction in production and fertilizer use could cut down on this pollution. Treatment of waste - human and animal - would be wise as well. But the focus is solely on profit and production cost - not the larger effects of all this. We are seeing large scale environmental impacts from a variety of behavior on man's part. Yet we are NOT looking at ALL of these on a large scale level to see ALL the results.
Ironically, thre is evidence that man - in the past - has managed "sustainable farming" in some areas that today require large amounts of fertillizer in the short term (and are STILL not sustainable and must be abandoned - e.g. Amazonian Rain Forest). It seems like it is time for a re-think on how we manage agriculture.
It seems that a more rational approach is needed by government but - with a shortage of scientists and engineers in government - the focus is on "business". Frankly, few people pay attention to these issues - until there's a huge problem caused by such neglect. Of course the current Administration's denigration of "science" doesn't help. Some may feel "the Rapture" is coming and none of this matters..... I, however, would like a "Plan B" which deals with continued long term occupation of the planet by my descendents.... in a livable environment.