Laserfiche WebLink
bit high at 1,100 mg/L but not out of ranges associated with mining. There were trace <br />amounts of aluminum (0.65 mg/L), arsenic (0.007 mg/L), barium (0.065 mg/L), lead <br />(0.002 mg/L), manganese (1.2 mg/L), nickel (0.16 mg/L), uranium (0.007 mg/L) and <br />beryllium (0.011 mg/L). Of these metals, only aluminum, iron, manganese and beryllium <br />aze in excess of levels established by the EPA for drinking water. <br />Additionally, there were numerous metals and compounds for which there was "none <br />detected". Nitrate/Nitrate (<6 mg/L), total cadmium (<0.0006 mg/L), copper (<0.025 <br />mg/L), molybdenum (<0.25 mg/L), selenium (<0.001 mg/L), silver (<0.0005 mg/L) and <br />zinc (<0.05 mg/L) all fall into this category. <br />The portal spring water was also tested for various organic constituents as well. The <br />compounds tested for were volatile organic compounds (VOC's) and semi-volatile <br />organic compounds (SVOC's). These include chemicals such as herbicides, pesticides, <br />benzene, toluene, xylene, creosol and all organics with chain lengths less than 20-30 <br />carbons (gasoline, many oils and most organic solvents). These screens resulted in no <br />known organic compounds being detected. The one item of interest, however, was on the <br />SVOC screen. This screen indicated the presence of possible high-molecular weight <br />organic acids. <br />It is these (possible) high-molecular weight acids that are the basis of the theory for the <br />coloration of the Edwards Mine Portal spring. Upon reviewing the laboratory data, a <br />search was conducted in an attempt to determine what, if any, high-molecular weight <br />organic acids might logically be present. The search turned up one possible "suspect" <br />and that "suspect" is humic acid. Humic acid is not one single, discrete organic molecule <br />like benzene, dodecane or ethanol. It is, rather, a name used for a family of related <br />molecules that shaze common features and properties, like azomatic hydrocarbons <br />(unsaturated ring compounds of which there are literally hundreds of individual <br />molecules). Aside note: Although many greases and lubricants ahigh-molecular weight <br />organics, the fact that they are insoluble in water eliminated them from consideration. <br />Although organic acids are called acids, they act nothing like inorganic acids in that they <br />do not completely (or partially, depending on the acid) dissociate in water and form the <br />hydronium ion (H30~. It is the hydronitun ion concentration that determines an acid <br />solution's strength (pH or pKa) and is ultimately responsible for the acid's corrosive <br />properties. Organic acids are very weak "acids" that contain a carboxyl group (- <br />000H). It is the hydrogen in the carboxyl group that has the (very, very limited) ability <br />to dissociate to form the hydronium ion and the complimentary base (-COO"). This is a <br />very limited reaction (as opposed to the instantaneous and complete dissociation of <br />inorganic acids) and quickly forms an equilibrium, which gives rise to a very small (if <br />any) drop in the pH of a solution. Amino acids are organic acids and they are no more <br />corrosive than something like common flour. <br />Besides being extremely interesting, all of this chemistry is important because it means <br />that organic acids are not corrosive, the way inorganic acids are, and they will not, if <br />present in mine waters, produce the characteristics of acid mine drainage (AMD). This is <br />