As part of the Pesticide Monitoring Program, groundwater samples were also collected for inorganic chemical analyses. Of particular interest were the Nitrate and Perchlorate concentrations.
Nine of the 60 (15%) public supply wells sampled in Nassau County exhibited perchlorate detections. The detections ranged from 2 ug/L to 6 ug/L, well below the New York State Department of Health (NYSDOH) Action Level for this compound of 18 ug/L. All detections occurred in the Magothy aquifer, with depths ranging from 298 to 682 feet. Perchlorate was found in the public supply wells from 7 different water systems and 2 water systems, Hicksville Water District and The Town of Hempstead W.S. had detections in two of their wells. Table 2 summarizes the perchlorate detections in Nassau County's public supply wells.
|WATER SYSTEM||LOCAL WELL NO.||NYSDEC WELL NO.||AQUIFER||WELL DEPTH||SAMPLE DEPTH||PERCHLORATE (UG/l)|
|Bethpage Water District||BDG1||N-9561||Magothy||682 ft.||9/26/01||3|
|Garden City Village||13||N-7058||Magothy||440 ft.||9/25/01||3|
|Glen Cove City||Kelly||N-9334||Magothy||298 ft.||8/6/01||3|
|Hicksville Water District||6-2||N-3878||Magothy||428 ft.||10/15/01||5|
|Hicksville Water District||9-1||N-8778||Magothy||590 ft.||10/31/01||2|
|Jericho Water District||13||N-6093||Magothy||606 ft.||10/15/01||2|
|Roslyn Water District||8||N-8010||Magothy||448 ft.||8/14/01||2|
|Town of Hempstead W.S.||B.G.#1||N-8956||Magothy||530 ft.||1/9/02||6|
|Town of Hempstead W.S.||B.G.#2||N-8957||Magothy||584 ft.||1/9/02||2|
The average nitrate concentration found in the 61 public supply wells sampled in 2001 was 2.5 mg/L and no wells exceeded the nitrate MCL of 10.0 mg/L. Well N-3523, "Munsey Park # 8", from the Manhasset-Lakeville Water District had the highest nitrate concentration of 9.8 mg/L. The range of nitrate detections is summarized below.
|NO3 Detection Range||>10 mg/L||5-10 mg/L||0-5 mg/L||ND|
|# PSW Detected||0||15||28||21|