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
| PESTICIDE | WELLS(S) DETECTED | LOCATION | LEVEL
(ug/L) | MCL
(UG/L) |
|---|
| Atrazine | N-3704 | WestHempstead W.D. | 0.19 | 3.0 |
| Desethyhtrazine | N-9211 | City of Glen Cove | 0.05 | 50.0 |
DBCP
(Dibromachbropropane) | N-9211 | City of Glen Cove | 0,11 | 0.12 |
EDB
(Ethylenedibromide) | N-8010 | Roslyn Water District | 0.07* | 0.05 |
| Prometon | N-4077 | W.A. of Western Nassau | 0.12 | 50.0 |
| TCPA | N-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.