By Dr Deepu
Arsenic is a semi-metal element in the periodic table. It is
odorless and tasteless. It enters drinking water supplies from natural deposits
in the earth or from agricultural and industrial practices.
Non-cancer effects can include
thickening and discoloration of the skin, stomach pain, nausea, vomiting;
diarrhea; numbness in hands and feet; partial paralysis; and blindness. Arsenic
has been linked to cancer of the bladder, lungs, skin, kidney, nasal passages,
liver, and prostate.
EPA has set the arsenic standard for drinking
water at .010 parts per million (10 parts per billion) to protect consumers
served by public water systems from the effects of long-term, chronic exposure
to arsenic. Water systems must comply with this standard by January 23,
2006, providing additional protection to an estimated 13 million Americans.
EPA proposed arsenic regulations to revise the existing NPDWR on
June 22, 2000 (65 FR 38888), which proposed a Maximum Contaminant Level (MCL)
of 0.005 mg/L (5 μg/L). The October 2000 appropriations bill for EPA amended
the SDWA, directing EPA to promulgate a final arsenic standard no later than
June 22, 2001. The Final Rule, published on January 22, 2001, established the
MCL at 0.01 mg/L (10 μg/L) (40 CFR 141.62(b)(16)). The Rule was to become
effective on March 23, 2001, 60 days after publication. The Rule established
that the 0.01 mg/L (10 μg/L) MCL becomes enforceable on January 23, 2006, and
that the clarifications to compliance and new source contaminants monitoring
regulations become enforceable on January 22, 2004 (40 CFR 141.6(j) & (k)).
Because of the importance of the Arsenic
Rule and the national debate surrounding it related to science and costs, EPA's
Administrator publicly announced on March 20, 2001, that the Agency would
take additional steps to reassess the scientific and cost issues associated
with this Rule. EPA requested that the National Academy of Sciences (NAS)
convene a panel of scientific experts to review the Agency's interpretation and
application of arsenic research, worked with its National Drinking Water
Advisory Council (NDWAC) to review the assumptions and methodologies underlying
the Agency's estimate of arsenic compliance costs, and asked its Science Advisory
Board (SAB) to look at the benefits associated with the Rule. On October 31,
2001, the EPA Administrator announced that the 10 ppb (0.010 mg/L) standard for
arsenic would remain stating that, "the 10 ppb protects public health
based on the best available science and ensures that the cost of the standard
is achievable."
On January 22, 2001
EPA adopted a new standard for arsenic in drinking water at 10 parts per
billion (ppb), replacing the old standard of 50 ppb. The rule became
effective on February 22, 2002. The date by which systems must comply
with the new 10 ppb standard is January 23, 2006.
