Contaminant

MCL (mg/L,

except asbestos)

Method

Detection Limit (mg/L)

Antimony

0.006

Atomic absorption − furnace technique

0.003

Atomic absorption − furnace technique (stabilized temperature)

0.0008⁵

Inductively coupled plasma-mass spectrometry

0.0004

Atomic absorption − gaseous hydride technique

0.001

Arsenic

0.010

Atomic absorption − furnace technique

0.001

Atomic absorption − furnace technique (stabilized temperature)

0.00005⁶

Atomic absorption − gaseous hydride technique

0.001

Inductively coupled plasma-mass spectrometry

0.0014⁷

Asbestos

7 MFL¹

Transmission electron microscopy

0.01

MFL

Barium

2

Atomic absorption − furnace technique

0.002

Atomic absorption − direct aspiration technique

0.1

Inductively coupled plasma arc furnace

0.002

Inductively coupled plasma

0.001

Beryllium

0.004

Atomic absorption − furnace technique

0.0002

Atomic absorption − furnace technique (stabilized temperature)

0.00002⁵

Inductively coupled plasma²

0.0003

Inductively coupled plasma-mass spectrometry

0.0003

Cadmium

0.005

Atomic absorption − furnace technique

0.0001

Inductively coupled plasma

0.001

Chromium

0.1

Atomic absorption − furnace technique

0.001

Inductively coupled plasma

0.007

Inductively coupled plasma

0.001

Cyanide

0.2

Distillation, spectrophotometric³

0.02

Automated distillation, spectrophotometric³

0.005

Distillation, selective electrode³

0.05

Distillation, amenable, spectrophotometric⁴

0.02

UV, distillation, spectrophotometric⁸

0.0005

Micro distillation, flow injection, spectrophotometric³

0.0006

Ligand exchange with

amperometry⁴

0.0005

Mercury

0.002

Manual cold vapor technique

0.0002

Automated cold vapor technique

0.0002

Nickel

No MCL

Atomic absorption − furnace technique

0.001

Atomic absorption − furnace technique (stabilized temperature)

0.0006⁵

Inductively coupled plasma²

0.005

Inductively coupled plasma-mass spectrometry

0.0005

Nitrate (as N)

10

Manual cadmium reduction

0.01

Automated hydrazine reduction

0.01

Automated cadmium reduction

0.05

Ion-selective electrode

1

Ion chromatography

0.01

Capillary ion

electrophoresis

0.076

Nitrite (as N)

1

Spectrophotometric

0.01

Automated cadmium reduction

0.05

Manual cadmium reduction

0.01

Ion chromatography

0.004

Capillary ion

electrophoresis

0.103

Selenium

0.05

Atomic absorption − furnace technique

0.002

Atomic absorption − gaseous hydride technique

0.002

Thallium

0.002

Atomic absorption − furnace technique

0.001

Atomic absorption − furnace technique (stabilized temperature)

0.0007⁵

Inductively coupled plasma-mass spectrometry

0.0003

Footnotes.

¹

"MFL" means millions of fibers per liter less than 10 μm.

²

Using a 2x preconcentration step as noted in USEPA 200.7 (94). Lower MDLs are possible when using a 4x preconcentration.

³

Screening method for total cyanides.

⁴

Measures "free" cyanides when omitting distillation, digestion, or ligand exchange.

⁵

Lower MDLs are possible using stabilized temperature graphite furnace atomic absorption.

⁶

The MDL for USEPA 200.9 (94) (atomic absorption-platform furnace (stabilized temperature)) resulted using a 2x concentration step during sample digestion.  The MDL using direct analyses (i.e., no sample digestion) is higher.  Using multiple depositions, USEPA 200.9 (94) can obtain an MDL of 0.0001 mg/L.

⁷

Using selective ion monitoring, USEPA 200.8 (94) (ICP-MS) is capable of obtaining an MDL of 0.0001 mg/L.

⁸

Measures total cyanides when using UV-digestor and "free" cyanides when bypassing UV-digestor.