Ammonium Ion, Humic Materials, and Trihalomethane Potential in Northeastern Kansas Ground Waters

Abstract

Glacial buried‐valley aquifers serve as primary sources of potable ground water in northeastern Kansas. A long known problem, however, is that a large percentage of well waters in this region exceed the U.S. Environmental Protection Agency (EPA) limits for nitrate (NO−3). A detailed study of the hydrogeology and water quality of the buried valleys has confirmed the nitrate problem and led to a recognition that some well waters with low ( 5 mg/l) NO−3 concentrations have anomalous ( 0.5 mg/l) ammonium ion (NH+4) levels, with an NH+4 range from <0.1 to 4.8 mg/l. The extractable NH+4 concentrations in related glacial sediments range up to approximately 75 mg/kg, and the amounts generally increase from an average of 2 mg/kg in the topsoil downward to bedrock. Migration of brines from subjacent Permian or Pennsylvanian bedrock into the unconsolidated sediments locally may cause desorption of NH+4 and an increase in its levels in the associated ground waters. Numerous test holes drilled in the study area showed a black scum on the fluid and cuttings, which may be from buried humic materials. Recently measured total organic carbon (TOC) contents of the ground waters confirm a significant level in some areas, with a range from 0.1 to 2.4 mg/l as C. Chlorination of water with dissolved organics may lead to production of halogenated compounds. Two public‐water‐supply well waters contained total trihalomethane (TTHM) levels close to the maximum contaminant level (MCL) of 100 /μg/l in chlorinated samples quenched after one week. The presence of NH+4 inhibits the formation of THMs, but it also can give rise to odor and taste problems in the finished water. The inhibition of THM formation by NH+4 is achieved by reactions which compete with the organics for combination with chlorine. These reactions make maintaining appropriate chlorine residuals difficult and also may lead to production of undesirable side products. Present efforts to evaluate the regional water‐quality problems are focused in Nemaha County, Kansas.

Retardation of ammonium and potassium transport through a contaminated sand and gravel aquifer: the role of cation exchange

“…Both NH4+ and N03" are common contaminants that result from pollution caused by fertilizer application and disposal of human and animal wastes (1-8). Dissolved NH4+ can cause taste, odor, and health problems in drinking water supplies (9), and dissolved N03~c an cause methemoglobinemia in infants at concentrations >10 mg/L as N (10). The fate of NH4+ and N03~i n groundwater is largely determined by the microbiology and geochemistry of the subsurface (11).…”

Occurrence and Distribution of Ammonium in Iowa Groundwater

“…Simpkins and Parkin (1993) and Parkin and Simpkins (1995) observed unusually high concentrations of dissolved organic carbon (up to 54 mg/L) in till and loess in central Iowa, which they attributed to degradation of complex organic material (i.e., wood) disseminated in the glacial materials. Denne et al (1984) and Denne et al (1987) studied glacial buried-valley aquifers in northeastern Kansas and found concentrations of TOC from 0.9 to 2.4 mg/L derived from buried humic materials sufficient to sustain relatively high ammonium concentrations (0.5 to 4.2 mg/ L). Larson and Roy (2000) traced high ammonium concentrations in portions of Illinois to the organic-rich, buried Sangamon Geosol developed on Wisconsinan-age deposits.…”

“…In Kansas, Denne et al (1987) observed an extremely strong correlation of high extractable ammonium concentrations measured in interbedded silty clay layers with high ammonium concentrations detected in the adjacent buried channel aquifer. Extractable ammonium concentrations ranged up to 75 kg/kg in the glacial sediments (Denne et al, 1984). In a point-source study of contaminated wastewater discharge into a sandy aquifer, sorbed ammonium represented a large portion of the total nitrogen load in the aquifer and an available pool of ammonium to be released to the aquifer should equilibrium conditions change (DeSimone and Howes, 1998).…”

Trihalomethane formation potential: a tool for detecting non-specific organic groundwater contamination

“…In, contrast, ammonium inhibits the reaction by competing for reaction sites on the organic material (Denne et al, 1984). It may also react directly with chlorine, reducing the concentrations available to react with the organic matter.…”

“…This results in a high bromine incorporation into the THMs and may account for the mutagenic activity of chlorinated waters which cannot be solely ascribed to chloroform (Peters, 1994). However the presence of ammonia at concentrations as low as 1 mg l -1 inhibits haloform formation by competing for reaction sites on the organic molecules (Denne, 1984). Ammonia is generally present at low concentrations in unpolluted groundwater, but is high in domestic wastewater and can be high in landfill leachates (Robinson, 1996;Stuart & Klinck, 1998).…”