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(table) Concentrations and detection frequencies of compounds in ground water

[ug/L, micrograms per liter; --, no value available; MDL, method detection limit; MRL, minimum reporting level; NA, not available]


						  	      Median
				     Percentage   Detection   concen-	  Maximum     Human	   Percentage 	    Agricultural
				     of wells     threshold   tration of  concen-     health	   of wells	    pesticide
			   Trade     with	  MDL or MRL1 detections  tration     criteria2	   over health	    usage
Compound		   name	     detections   (ug/L)      (ug/L)	  (ug/L)      (ug/L)	   criteria	    rank3
--------		   -----     ----------   ----------  ----------  -------     --------	   -----------	    ------------
						  	     HERBICIDES
Atrazine		AAtrex		 45	     0.001	0.017	   0.97	       3 (mcl)		0		28
Simazine		Princep	  	 12	     0.005	0.008      0.011       4 (mcl)		0		47
Metribuzin		Lexone, Sencor	 10	     0.004	0.013      0.028     200 (ha)		0		12
Metolachlor		Dual		 10	     0.002	0.003      0.009     100 (ha)		0		25
Alachlor		Lasso	  	  6	     0.002	0.006	   0.008       2 (mcl)		0		17
EPTC	    		Eptam, Eradicane  6	     0.002	0.006	   0.012      --	       --		 5
2,4-D			several	   	  4	     0.035	0.275	   0.54	      70 (mcl)		0		16
Diuron			Karmex, Direx	  2	     0.02	 --        2.0	      10 (ha)		0		20
Bromacil4       	Hyvar, Urox B	  2	     0.035	 --        1.8	      90 (ha)		0		--
Ethalfluralin		Sonolan	  	  2	     0.004	 --        0.09	      --    	       --		53
2,4-DB			none	  	  2	     0.035	 --        0.06	      --	       --		40
Bentazon		Basagran	  2	     0.014	 --        0.07	      20 (ha)		0		26
Prometon4		Pramitol	  2	     0.018	 --        0.005     100 (ha)		0		--
Linuron	        	Lorox, Linex	  2	     0.002	 --        0.001      --	       --		30

						 	    INSECTICIDES
Dieldrin		Panoram D-31	  4	     0.001	0.01       0.013       0.002 (rsd)	4	    discontinued

					     		DEGRADATION PRODUCTS
Desethylatrazine	   none		 37	     0.002	0.007      0.12	      --	       --		NA
2,6-diethylanaline	   none	  	  4	     0.003	0.004      0.008      --	       --		NA
p,p'-DDE		   none	  	  2	     0.006	 --        0.001       0.1 (rsd)	0		NA

				       		 FUMIGANTS AND ASSOCIATED COMPOUNDS
1,2-dichloropropane5,6	    none	  12	      0.2	 0.25        0.5	5 (mcl)		 0	     discontinued
1,2,2-trichloropropane5,7   none	   8	      0.2	 0.26        0.55      --	       --		 NA
EDB8			Bromofume	  7	     0.04	0.31        1.1	       0.05 (mcl)	5	    discontinued
1,2,3-trichloropropane5	   none	  	  6	     0.2	0.5	    1.0	      --	       --		NA
1,3-dichloropropane5	   none	  	  2	     0.2	 --	    0.5	      --	       --		NA
Bromoform		   none	  	  2	     0.2	 --	    0.12      --	       --		NA

1The MDL is reported for the herbicides, insecticides, and degradation products; the MRL is reported for the fumigants. 2Human health criteria are either the maximum contaminant level (MCL), set by the EPA to be the maximum concentration allowed in drinking water, the lifetime health advisory level (HA), which is the maximum concentration in drinking water that would not cause adverse human health effects, excluding cancer (based on a 150-pound adult consuming about 2 quarts of water per day for 70 years), or the risk-specific dose (RSD), which is the concentration that corresponds to an increase of a 1 in one million chance of developing cancer. 3Calculated from the amount of pesticide applied to irrigated row crops in the study area in tons per year out of 103 pesticides 4Nonagricultural herbicide 5Many of the chlorinated propanes are by-products of manufacturing 1,3-dichloropropene and may be present in 1,3-dichloropropene- based formulations such as Telone II and D-D 92. 61,2-dichloropropane was an active ingredient in some nematocide formulations (Telone, Shell D-D) until it was discontinued in 1976. 7Values for this compound are estimated. 8EDB(1,2-dibromoethane) was analyzed for in 41 wells.

Any use of trade names is for descriptive purposes only and does not imply endorsement by the U.S. Government.


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