A Maximum Contaminant Level (MCL) is the highest level of a contaminant that is allowed in drinking water. Two of the 29 primary contaminants are handled somewhat differently in this report. The first exception is lead, which has an Action Level of 15 ug/L. An Action Level is different than an MCL. Since the majority of lead in drinking water is attributed to leaching from the pipes and distribution system, the action required by the Safe Drinking Water regulations centers on corrosion control and public notice. Since the PWTA program requires testing of untreated water, the State's Ground Water Quality Standard (GWQS) is used as a surrogate in the absence of an MCL established under the Safe Drinking Water Act. An exceedance for lead under the PWTA is thus determined by comparing the well test results to the GWQS. The GWQS for lead was lowered from 10 micrograms per liter (µg/l) to 5 µg/l on November 7, 2005.
The second exception is arsenic. The MCL in effect for arsenic when the PWTA was signed was 50 µg/l. The USEPA adopted a new MCL of 10 µg/l on January 22, 2002 (effective February 22, 2002): however, those public water systems required to comply with the new arsenic standard had until January 23, 2006 to do so. For the purposes of the PWTA, the NJDEP used the newly adopted Federal MCL of 10 ug/l for assessing the PWTA results beginning in September 2002. On January 23, 2006, the same date that compliance with the federal MCL became mandatory for certain public water systems, a new State MCL of 5µg/l became effective. After January 23, 2006, 5 ug/l was the MCL used to determine PWTA compliance. This report evaluates the arsenic test results based on 10 µg/l, and the more recent test results based on 5 µg/l.
Primary Contaminants: Protecting Human Health
Primary Drinking Water Standards are established for contaminants that have either an immediate or long-term effect on human health. Based on the results of the 51,028 wells tested between September 2002 and April 2007, 88 percent (%) of the wells “passed” (did not exceed) all of the required primary standards for drinking water. Of the 12 % (6,369) wells that exceeded a primary drinking water standards (“failed”), the most common exceedances were for gross alpha particle activity2 (2,209 wells), arsenic3 (1,445 wells), nitrates (1,399 wells), fecal coliform or E. coli (1,136 wells), volatile organic compounds (VOCs) (702 wells), and mercury4 (215 wells). A summary of the primary contaminant test results is presented in Figure E1.
Secondary Parameters: Measuring Natural Water Quality Characteristics
The PWTA requires testing for three naturally occurring secondary drinking water parameters: pH, iron, and manganese. Secondary drinking water parameters are contaminants that cause aesthetic problems such as corrosivity of plumbing fixtures, and taste and odor problems. Secondary parameters also affect the water’s suitability
The following counties are required to test for gross alpha: Atlantic, Burlington, Camden, Cape May, Cumberland, Gloucester, Monmouth, Ocean, Salem, Mercer, Hunterdon, and Middlesex The following counties are required to test for arsenic: Bergen, Essex, Hudson, Hunterdon, Mercer, Middlesex, Morris, Passaic, Somerset, and Union. The following counties are required to test for mercury: Atlantic, Burlington, Camden, Cape May, Cumberland, Gloucester, Monmouth, Ocean, and Salem.