Monitoring Results From Public Supply Wells

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Monitoring Results From Public Supply Wells

Eight of the 66 public supply wells tested (12%) exhibited pesticide detections in 2001 and 6 different pesticides were detected in Nassau County public supply wells. TCPA (tetrachloroterephthalic acid), a dacthal metabolite, was the most frequently detected pesticide compound in Nassau County public supply wells, being detected in six of the 66 (9%) public supply wells tested in Nassau County. The detections ranged from 7 ug/L to 17 ug/L. The Maximum Contaminant Level (MCL) for this compound is the generic Unspecified Organic Contaminant (UOC) standard of 50 ug/L.

The 5 other pesticides that were detected in Nassau County public supply wells were: Atrazine, Dibromochloropropane (DBCP), Desethylatrazine, Ethylene dibromide (EDB) and Prometon. Table 1 lists the public supply well, water system and level detected for each detected pesticide in Nassau County.

Table 1 - Summary of Pesticides Detected in
Nassau County Public Supply Wells - 2001

PESTICIDEWELLS(S) DETECTEDLOCATIONLEVEL
(ug/L)
MCL
(UG/L)
AtrazineN-3704WestHempstead W.D.0.193.0
DesethyhtrazineN-9211City of Glen Cove0.0550.0
DBCP
(Dibromachbropropane)
N-9211City of Glen Cove0,110.12
EDB
(Ethylenedibromide)
N-8010Roslyn Water District0.07*0.05
PrometonN-4077W.A. of Western Nassau0.1250.0
TCPAN-10612
N-9211
N-37
N-12639
N-3704
N-10401
Garden City Park W.D.
City of Glen Cove
Sands Point Village
Sands Point Village
West Hempstead W.D.
West Hempstead W.D.
7
17
7
10
6
7
50.0
* Exceeds MCL of 0.05 ug/L established for this compound

Only one of the pesticides detected, Ethylene dibromide (EDB), exceeded the Maximum Contaminant Level (MCL) established for the compound. EDB was detected at a level of 0.07 ug/L in Roslyn Water District's Well # 8 (N-8010), exceeding the 0.05 ug/L MCL established for this compound. This well has a history of EDB detections from water system and NCDH routine monitoring and, since 1998, utilizes granular activated carbon (GAC) filtration.