Abandoned Mine Posts

by Andy McAllister, Watershed Coordinator

Acidity in our streams can come from a variety of sources; some natural and some not. The water in some streams, swamps and wetlands can be naturally acidic due in part, to the breakdown of plant material releasing Tannins or Tannic Acid. Tannins are responsible for the dark root beer-like appearance and slightly lower pH levels of some waterways.

However, very acidic conditions are most often the result of man’s influence on the environment. Two examples of this are Acid Mine Drainage (AMD) and Acid Rain.

Acid Mine Drainage forms principally from something called Iron Pyrite or “Fools Gold” that is associated with most coal deposits. Acid rain on the other hand, is caused by smoke from automobiles, manufacturing emissions, fossil fuel (oil, coal, and gas) combustion, forest fire smoke, and volcanic gases interacting with rain. When fossil fuels are burned they release sulphur dioxide and nitrogen oxides. These substances, when not removed from the emissions, mix with water vapor in the atmosphere to form Sulfuric Acid and Nitric Acid. Generally, rain with a pH lower than 5.5 qualifies as Acid Rain.

Acid rain eventually flows into streams and lakes, and if those streams cannot buffer the increasing acidity with naturally occurring limestone, they become acidic. The acidity causes such toxins as aluminium and other metals to become dissolved in the stream water. Once dissolved in the water, these metals become poisonous to fish and birds. Acidity in also kills trees and slowly eats away at limestone buildings and stone statues.

The byproducts of combustion that contribute to our acid rain find their way to us from other areas of the country “downwind” of Pennsylvania. The clouds form due in part to our mountainous topography wringing out the water from the atmosphere. The moisture-laden air bumps into the ridgetops in Western and Central PA and forms clouds which then release their acid in the form of rainfall. As a result, the coal regions of Pennsylvania get a “double dose” of acid, both in the form of acid rain and in the form of AMD.

Acid rain has been a widely recognized environmental threat in Europe since the 1950s but has only been acknowledged to be an increasing problem in the US since the 1970s. Technological improvements in fossil fuel combusion for powerplants have resulted in significant reductions of Sulfur compounds over the years but similar success in reducing Nitrogen compounds has yet to be realized.

Acid Rain
from Environment Canada

by Jeffrey Gerard, AmeriCorps OSM/VISTA

A new grant program in Pennsylvania will provide chemical analyses to monitor passive abandoned mine drainage treatment systems. The FACTS Grant (”Funding AMD Chemistry in Treatment Systems”) will ease the financial burden on cash-strapped grassroots watershed organizations that have accepted the responsibility of maintaining passive treatment systems.

Pennsylvania has invested heavily in passive technologies to treat the largest water pollution problem in the Commonwealth: abandoned mine drainage (AMD). Regular water sampling and testing is crucial in diagnosing a treatment system’s wellbeing and success. The FACTS Grant puts satisfactory monitoring programs within the reach of the volunteer-based groups by covering the cost of laboratory analyses—hundreds of dollars annually for each system.

In addition to funding the analyses, the FACTS Program streamlines the transfer of test results from laboratories using an Internet repository for water sampling data, called Datashed. Laboratories upload analysis results to Datashed using unique Sample IDs that link each water sample to a specific date, treatment system, and sampling location. Datashed will store the complete history of a passive treatment system, helping to diagnose problems and allowing researchers to study and evaluate various AMD treatment technologies.

The FACTS grant is administered by the Western and Eastern Pennsylvania Coalitions for Abandoned Mine Reclamation. Nonprofit watershed groups, county conservation districts, local governments, and RC&D councils in Pennsylvania can apply to the FACTS Grant program on the Web at http://www.wpcamr.org/facts.

In response to September 13th’s edition of Abandoned Mine Posts, “Filtering in the Field,” a number of experts sent us their advice and experiences about filtering water samples.

George Watzlaf, an Environmental Engineer with the U.S. Department of Energy, clarified that a 0.45 micron filter is used to separate dissolved and suspended elements, meaning the holes are about the size of a single wavelength of light! Our newsletter had also said that acid is consumed if ferrous iron oxygenates into ferric iron en route to the analysis laboratory; this is correct, but Mr. Watzlaf points out that “the oxidized ferric iron will precipitate immediately with the net effect of producing acid.”

Finally, Penn State Professor Emeritus Art Rose notes that filtering can even help determine what mine drainage treatment methods should be employed for a given discharge. If a water sample analysis still shows metals after being filtered, these metals are dissolved and treatment requires chemical treatment before a settling pond. Alternatively, if the water only contains suspended particulates, which the filter removes, a settling pond alone is sufficient.

by Jeffrey Gerard, AmeriCorps OSM/VISTA

Filtering water samples in the field can be a pain in the butt, but it’s also a crucial step in getting the most accurate analysis data.

Filtering involves forcing water through a membrane filled with tiny holes, about 25 microns across (¼ of a human hair). The filter removes suspended solids from the water, and in fact, the weight of the solids caught in the filter is one common analysis parameter: total suspended solids (TSS). Such solids can be virtually invisible to the naked eye, but not dissolved, so they’ll eventually settle out if the sample is left undisturbed.

AMD-impacted water can have tiny bits of iron hydroxide (a.k.a. yellowboy) suspended in it. In a water sample fixed with acid but not filtered in the field, this iron hydroxide will dissolve into the water before it arrives at the laboratory, which will give incorrect test results for metals. Alternatively, in unacidified water samples, dissolved oxygen can cause dissolved ferrous iron to oxygenate into ferric iron en route to the lab. Unless the insoluble ferric iron is filtered out at sampling time, the lab can’t determine how much ferrous vs. ferric iron the water actually contained when it was sampled. Ferrous iron oxygenation also consumes acid, so certain lab acidity or pH measurements will be wrong.

Although filtering water samples eliminates these errors, it requires special equipment and training. Many groups — especially those that rely heavily on volunteers — leave filtering to the analysis laboratory, accepting any inaccuracies that creep in beforehand. Ultimately, the decision to filter relies on a group’s capacity and requirements, and it should be discussed with the chemical analysis lab that receives the water samples.