What ppb refer to regarding water testing

On January 22, 2001, EPA adopted a new standard for arsenic in drinking water of 0.01 mg/l or 10 parts per billion (ppb), replacing the old standard of 50 ppb. Water systems had to meet the new standard by January 23, 2006.

Explanation:

Water testing is a broad description for various procedures used to analyze water quality. Millions of water quality tests are carried out daily to fulfill regulatory requirements and to maintain safety.

Water testing is a broad description for various procedures used to analyze water quality. Millions of water quality tests are carried out daily to fulfill regulatory requirements and to maintain safety.Testing may be performed to evaluate:

Water testing is a broad description for various procedures used to analyze water quality. Millions of water quality tests are carried out daily to fulfill regulatory requirements and to maintain safety.Testing may be performed to evaluate:ambient or environmental water quality – the ability of a surface water body to support aquatic life as an ecosystem. See Environmental monitoring, Freshwater environmental quality parameters and Bioindicator.

Water testing is a broad description for various procedures used to analyze water quality. Millions of water quality tests are carried out daily to fulfill regulatory requirements and to maintain safety.Testing may be performed to evaluate:ambient or environmental water quality – the ability of a surface water body to support aquatic life as an ecosystem. See Environmental monitoring, Freshwater environmental quality parameters and Bioindicator.wastewater – characteristics of polluted water (domestic sewage or industrial waste) before treatment or after treatment. See Environmental chemistry and Wastewater quality indicators.

Water testing is a broad description for various procedures used to analyze water quality. Millions of water quality tests are carried out daily to fulfill regulatory requirements and to maintain safety.Testing may be performed to evaluate:ambient or environmental water quality – the ability of a surface water body to support aquatic life as an ecosystem. See Environmental monitoring, Freshwater environmental quality parameters and Bioindicator.wastewater – characteristics of polluted water (domestic sewage or industrial waste) before treatment or after treatment. See Environmental chemistry and Wastewater quality indicators."raw water" quality – characteristics of a water source prior to treatment for domestic consumption (drinking water). See Bacteriological water analysis and specific tests such as turbidity and hard water.

Water testing is a broad description for various procedures used to analyze water quality. Millions of water quality tests are carried out daily to fulfill regulatory requirements and to maintain safety.Testing may be performed to evaluate:ambient or environmental water quality – the ability of a surface water body to support aquatic life as an ecosystem. See Environmental monitoring, Freshwater environmental quality parameters and Bioindicator.wastewater – characteristics of polluted water (domestic sewage or industrial waste) before treatment or after treatment. See Environmental chemistry and Wastewater quality indicators."raw water" quality – characteristics of a water source prior to treatment for domestic consumption (drinking water). See Bacteriological water analysis and specific tests such as turbidity and hard water."finished" water quality – water treated at a municipal water purification plant. See Bacteriological water analysis and Category:Water quality indicators.

Water testing is a broad description for various procedures used to analyze water quality. Millions of water quality tests are carried out daily to fulfill regulatory requirements and to maintain safety.Testing may be performed to evaluate:ambient or environmental water quality – the ability of a surface water body to support aquatic life as an ecosystem. See Environmental monitoring, Freshwater environmental quality parameters and Bioindicator.wastewater – characteristics of polluted water (domestic sewage or industrial waste) before treatment or after treatment. See Environmental chemistry and Wastewater quality indicators."raw water" quality – characteristics of a water source prior to treatment for domestic consumption (drinking water). See Bacteriological water analysis and specific tests such as turbidity and hard water."finished" water quality – water treated at a municipal water purification plant. See Bacteriological water analysis and Category:Water quality indicators.suitability of water for industrial uses such as laboratory, manufacturing or equipment cooling.

"menstrual cycle is a complex cycle that consists of several processes. order of occurrence of steps in menstrual cycle are as follows:

1. high progesterone levels maintain the endometrium lining of the uterus.

2. endometrium lining breaks down and low levels of estrogen stimulate the pituitary to release fsh and lh.

3. fsh and lh stimulates the follicles to develop and the oocyte to produce estrogen.

4. rising estrogen levels suppress fsh production and development of other follicles.

5. a spike in lh causes follicle to rupture.

6. a breakdown of corpus luteum causes progesterone level to drop."

it is either c or d and i know for sure it is not a or b