Pesticide Residues in Surface Water and Groundwater - Pesticides: Evaluation of Environmental Pollution - page 273

TABLE 9.5
Maximum Contaminant Levels for Pesticides in Drinking Water Set by EPA

MCL or
TT (μg/L)
Alachlor Chloroacetanilide Herbicide 0 2
Atrazine Triazine Herbicide 3 3
Carbofuran Carbamate Insecticide 40 40
Chlordane Organochlorine Insecticide 0 2
2,4-D Phenoxy Herbicide 70 70
Dalapon Organochlorine Herbicide 200 200
1,2-Dibromo-3-chloropropane — Nematocide 0 0.2
Dinoseb Dinitrophenol Herbicide 7 7
Diquat Desiccant Herbicide 20 20
Endothall Dicarboxylic acid Herbicide 100 100
Endrin Organochlorine Insecticide 2 2
Glyphosate Glycine derivative Herbicide 700 700
Heptachlor Organochlorine Insecticide 0 0.4
Heptachlor epoxide Organochlorine Insecticide 0 0.2
Lindane Organochlorine Insecticide 0.2 0.2
Methoxychlor — Insecticide 40 40
Oxamyl (Vydate) Carbamate Insecticide 200 200
Picloram Pyridinecarboxylic acid Herbicide 500 500
Simazine Triazine Herbicide 4 4
Toxaphene — Insecticide 0 3
2,4,5-TP (Silvex) — Herbicide 50 50
Source: US EPA. 2002. National Primary Drinking Water Regulations. http://water.epa.gov/drink/
contaminants/index.cfm#Organic (accessed 28 January 2011.)
MCLG, maximum contaminant level goal; MCL, maximum contaminant level; TT, treatment technique
(a required process intended to reduce the level of a contaminant in drinking water).

MCLG
(μg/L) Pesticide Chemical Class Activity

In contrast, the levels of pesticides found in drinking water in Canada were quite low. For
example, in the period from 1986 to 2006, from 675 drinking water systems in Canada,
16,166 water samples were tested for 104 pesticides and pesticide degradation products.
Only in four samples the concentrations of atrazine or terbufos exceeded the guideline
values of the Ontario Drinking Water Quality Standards (McInnis 2010).
Because of the complexity of water treatment technology associated with local water
quality conditions and natural treatment systems such as bank filtration (Maeng et al.
2010), it is difficult to establish the standard criteria for defining pesticide-secure water
treatment. In order to achieve an adequate control of pesticides in drinking water, it is also
necessary to know details of their behavior under drinking water treatment conditions.
Water treatment data can be derived from studies providing information on the removal
efficiency of the pesticide and the identification of transformation by-products obtained in
the laboratories, pilot plant and actual water treatment plant monitoring studies.

9.4.1 Water Treatment Technology

Water treatment involves the deliberate addition of numerous chemicals to improve the
safety and quality of the drinking water produced for consumers. The conventional chem-
icals and materials used in water treatment plants and their effect on pesticide removal