Acute – occurring over a short time, usually minutes to hours.

Acute Exposure – either one or a series of several short-term exposures (or doses) generally lasting less than 24 hours.

Acute Myocardial Infarction (AMI) - heart attack.

Age-Adjusted Rates - a measure that controls for the effects of age differences on health event rates. When comparing across geographic areas, some method of age-adjusting is typically used to control for the influence that different population age distributions might have on health event rates. Age-adjustment may also be used to control for age effects when comparing across several years of data, as the age distribution of the population changes over time.

Air Quality Index (AQI) - the U.S. Environmental Protection Agency (EPA) developed the AQI to communicate to the public daily air quality for five criteria air pollutants: ground-level ozone, particulate matter, sulfur dioxide, carbon monoxide and nitrogen dioxide. The AQI reports how clean or polluted the air is on a given day and whether air quality at a given time poses a risk to health using a color-coded yardstick that runs from zero to 500. More info: https://www.airnow.gov/?city=Newark&state=NJ&country=USA

Ambient Air - any unconfined portion of the atmosphere; outdoor air.

Analyte – a chemical or substance for which a sample (for example water, air, or blood) is measured in a laboratory.

Aquifers - underground geological formations, or groups of formations, that can store or transmit water. Aquifers are sources of groundwater for wells and springs. Common use of the term normally refers to water-bearing formations capable of yielding enough water to provide a usable supply.

Arsenic - a naturally occurring element widely distributed in the earth's crust. In the environment, arsenic is combined with oxygen, chlorine, and sulfur to form inorganic arsenic compounds. Inorganic arsenic compounds are commonly used to preserve wood. Arsenic in animals and plants combines with carbon and hydrogen to form organic arsenic compounds. Organic arsenic compounds are used as pesticides on plants including cotton, fruit and nut trees, turf, and lawns.

Asthma - a serious, chronic lung disease that causes the airways (bronchial tubes) to become narrow and makes it harder to breathe.  Asthma attacks are often caused by environmental triggers, such as pollen, air pollution, mold, dust mites, and tobacco smoke.

Average Annual Count - an average (the mean), over a multi-year period, of the number of specific events which occur each year during that period.

Average Annual Rate - an average (the mean), over a multi-year period, of the rates or proportions seen annually during that period.

Background Level - a concentration of a substance in an environmental medium (air, water, or soil) that occurs naturally and is not the result of human activities. Background level concentrations provide a baseline reference point to evaluate additional human-generated emissions or other changes. 

Behavioral Risk Factor Surveillance System (BRFSS) - a large continuously conducted telephone health survey which enables the Centers for Disease Control and Prevention (CDC), state health departments, and other health agencies to monitor modifiable risk factors for chronic diseases and leading causes of death. More info: https://www.cdc.gov/brfss/  

Birth Defects - an abnormal condition that occurs before or at the time of birth. Birth defects include a wide range of abnormalities with varying levels of impact.  Examples of birth defects include: spina bifida, cleft palate, upper and lower limb deformities.

Body Mass Index (BMI) - a person's weight in kilograms (kg) divided by their height in meters squared.  A BMI below 18.5 is considered underweight, BMI between 18.5 and 24.9 is considered a healthy weight, and BMI between 25 and 29.9 is considered overweight.

Brownfield – as defined under NJ law (N.J.S.A. 58:10B-23.d), any former or current commercial or industrial site that is currently vacant or underutilized and on which there has been, or there is suspected to have been, a discharge of a contaminant.  While this is the definition recognized in state legislation, there are many variations on this definition.  Generally, brownfields are properties that are abandoned or underutilized because of real or perceived contamination.

Cancer - any one of a group of diseases which occur when cells in the body become abnormal and grow or multiply out of control.

Carbon Monoxide (CO) - an odorless, colorless gas that can cause severe illness or death in a matter of minutes if inhaled in high levels. CO is given off when fuel or other materials are burned.

Carbon Monoxide (CO) Poisoning - a disease that reduces the amount of oxygen getting to the brain and vital organs.  As CO gas is inhaled, it decreases oxygen in the blood, leading to headache, dizziness, nausea, and at high concentrations, unconsciousness, or death.

Carcinogens - substances such as radionuclides, asbestos, radon, vinyl chloride, and benzene, that can directly initiate or promote cancer.

Cardiovascular Disease - refers to a group of diseases and conditions affecting the heart and blood vessels, with heart attack and stroke occurring most frequently.  Congestive heart failure, hypertension (also known as high blood pressure), and disease of the arteries, veins, and circulatory system are the other diseases and conditions included in the term cardiovascular disease.

Census - a procedure of systematically acquiring and recording information about the members of a given population.  A census of the U.S. population is taken every ten years to apportion the number of members of the United States House of Representatives for each state.  Census statistics are often used to apportion federal funding for many social and economic programs.  More info: https://www.census.gov/

Census Block - the smallest geographic entity for which the U.S. Census tabulates decennial census data.  Many census blocks correspond to city blocks bounded by streets but blocks in rural areas may include several square miles and have boundaries that are not streets. More info: https://www.census.gov/.

Census Block Group - a unit of U.S. Census geography that is an aggregation of census blocks. A block group is the smallest unit for which the U.S. Census Bureau reports a full range of demographic statistics. There are about 700 residents per block group. A Census block group is a subdivision of a census tract.  More info: https://www.census.gov/.

Census Tract - a combination of census block groups. designed to encompass a population with relatively uniform economic status, living conditions, and some demographic characteristics. Tract boundaries normally follow physical features but may also follow administrative boundaries or other non-physical features.  A census tract usually includes approximately 4,000 residents but can include between 2,500 to 8,000 residents.    

Center for Health Statistics and Informatics (CHS), New Jersey Department of Health - collects, researches, analyzes, and disseminates New Jersey health data and information and serves as a resource to the NJ Department of Health in developing health data policy. More info: https://www.nj.gov/health/chs.

Centers for Disease Control and Prevention (CDC) – a federal public health agency within the U.S. Department of Health & Human Services. More info: https://www.cdc.gov/.

Childhood Lead Poisoning Prevention Program (CLPPP) - a New Jersey Department of Health program to prevent, screen, diagnosis, and treat lead poisoning, including the elimination of sources of poisoning through research and educational, epidemiologic, and clinical activities.

Chronic Effect - an adverse health impact on an organism in which symptoms recur frequently or develop slowly over a long period of time.  The term “chronic” can also apply to exposure and toxicity. The term is usually applied to a condition spanning several weeks, months or years.

Chronic Obstructive Pulmonary Disease (COPD) - a term used to describe progressive lung diseases including emphysema, chronic bronchitis, and non-reversible asthma.

Community Water System (CWS) - a public water system that serves year-round community residents (at least 25 people or at least 15 service connections).

Combined Sewer Overflow (CSO) - discharges of wastewater that exceeds the volume capacity of combined sewer systems that collect rainwater, runoff, domestic sewage, and industrial wastewater into one pipe directly into nearby streams, rivers, and other water bodies. CSOs can contain untreated or partially treated human and industrial waste, toxic materials, and other debris, and often contain high levels of total suspended solids, pathogens, nutrients, oxygen-demanding organic compounds, oil, and grease.  

Concentration - the relative amount of a substance mixed with another substance.  Examples are "five parts per million (ppm) of carbon monoxide in air" or "1 milligram per liter (mg/L) of lead in water."

Confidence Interval (CI) - the confidence interval is the range of probable true values for a statistic.  In general, as a population or sample size increases, the confidence interval gets smaller. Estimates with smaller confidence intervals are referred to as more "precise." Less precise estimates, such as those calculated from small numbers, will have wider confidence intervals.  More info: https://www-doh.state.nj.us/doh-shad/home/ConfidenceInterval.html .  

Contaminant –a biological, chemical, physical or radiological substance that becomes harmful for humans or living organisms, when accidentally or deliberately introduced to air, water, soil or food. Contaminants are also known as pollution in environmental science when referring to pollution on a large scale in relation to humans or living organisms.

Contamination - presence of contaminants in the air, water, or soil.

Criteria Pollutants - six common air pollutants, carbon monoxide, lead, nitrogen dioxide, ozone, particulate matter, and sulfur dioxide that have National Ambient Air Quality Standards established by the U.S. Environmental Protection Agency to define allowable concentrations in ambient air.

County – a level of government between the State and municipalities.  New Jersey has 21 counties that together contain 564 municipalities or administrative entities composed of clearly defined territory (249 boroughs, 52 cities, 15 towns, 244 townships, and 4 villages).

Crude Rate - the number of events (such as deaths) in a specified time interval divided by the number of people at risk for these events (typically, a state or county population) during that same period. This figure is generally multiplied by a constant such as 1,000 or 100,000 to get a number that is easy to read and compare and reported as “per 1,000” or “per 100,000.” Crude rates adjust for differences in population size but not for differences in population characteristics, such as age.

Denominator - the lower portion of a fraction used to calculate a rate or ratio.

Detection limit - the lowest concentration of a single substance that can reliably be distinguished from a zero concentration.

Disease Rate - a measure of how frequently a disease occurs in a population over a specified time interval.

Disinfection Byproducts (DBP) - the result of combining disinfectants like chlorine with organic matter. Disinfectants are added to drinking water to kill or inactivate harmful organisms that cause various diseases. The most commonly-formed DBPs are trihalomethanes (THMs), and haloacetic acids (HAAs).

Drinking Water Standards - regulations set by the USEPA to control the level of contaminants in the nation's drinking water. The regulations also require water monitoring schedules and methods to measure contaminants in water. Primary drinking water standards are legally enforceable standards that apply to public water systems.  Secondary drinking water standards are non-enforceable guidelines for contaminants that may cause cosmetic (e.g., skin discoloration) or aesthetic (e.g., strange odor or color) effects from drinking water.

Emission - pollution discharged into the atmosphere from smokestacks, other vents, and surface areas of commercial or industrial facilities; residential chimneys; and motor vehicles, locomotives, ships, or aircraft.

Environment - air, water, soil, and food and the contaminants found within them.

Environmental Contaminant - a pollutant in the environment.

Environmental Hazard - any condition or situation in the environment which poses a threat to human health or safety.

Environmental Justice - the fair treatment and meaningful involvement of all people regardless of race, color, national origin, or income with respect to the development, implementation, and enforcement of environmental laws, regulations, and policies.

Environmental Protection Agency (EPA) - the U.S. federal agency designated to protect human health and safeguard the natural environment (air, water, and land). EPA provides leadership in the nation's environmental science, research, education, regulation, and assessment efforts. EPA sets national standards for a variety of environmental programs and delegates authority to states and tribes to issue permit and monitor and enforce compliance. More info: https://www.epa.gov/.

Environmental Public Health Tracking (EPHT) - a series of CDC-funded projects promoting the ongoing collection, integration, analysis, interpretation, visualization, and dissemination of standardized data regarding environmental hazards, human exposure, and environmental health surveillance.  EPHT has developed a national EPHT Network which integrate and standardize environmental public health data and information from various monitoring and surveillance systems at the federal, state, and local levels.  More info: https://www.cdc.gov/nceh/tracking/index.html.

Epidemiology - the study of the distribution and determinants of health-related conditions or events in specified populations, and the application of this study to the control of health problems.

Ethnicity - often used synonymously with ancestry and includes concepts of culture, language, and national origin. Ethnic groups are often multi-racial.

Exposed (as in exposed group) - often used to connote a group whose members had contact with a suspected agent or cause of a disease.

Exposure - contact of an organism with a contaminant at a specific concentration for a specific time interval. 

Federal Highway Administration (FHWA) - an agency within the U.S. Department of Transportation that supports State and local governments in the design, construction, and maintenance of the Nation’s highway system (Federal Aid Highway Program) and various federally and tribal owned lands (Federal Lands Highway Program).

Fine Particulate Matter - particles less than 2.5 micrometers (µm) in diameter, also denoted as PM_2.5.

Frequency - the number of times an event occurs in a stated area or population within a stated time interval.

Geographic Information System (GIS) – a computer mapping system that collects, stores, manipulates, analyzes, and visually displays geographic data. For example, GIS can show the concentration of a contaminant within a community in relation to points of reference such as streets and homes.

Groundwater - water supplied by rain or melting snow that infiltrates the earth's surface in the spaces between soil particles and rock surfaces.

Haloacetic acids (HAA5) - byproducts resulting from the disinfection of public water supplies. Haloacetic acids are the sum of the concentrations of mono-, di-, and trichloroacetic acids and mono- and dibromoacetic acids.

Hazard - the potential for harm or an adverse effect.

Health Outcome - a disease or health condition measured or observed in a population or an individual. Also known as a health effect.

Hydrocarbon - a chemical compound consisting only of hydrogen and carbon. Hydrocarbons occur naturally in petroleum, natural gas, coal, and wood, and are emitted into the air when these fuel sources do not burn or burn only partially. Hydrocarbons react in the presence of nitrogen oxides and sunlight to form ground-level ozone. The most tracked hydrocarbons are volatile organic compounds (VOCs).

ICD-9 - International Classification of Disease, 9^th revision - a numbered system for classifying diseases and health conditions published by the World Health Organization and used as an international standard for epidemiological and health management purposes.

ICD-10 - International Classification of Disease, 10^th revision - published in 1990 as an updated version of ICD-9.

Incidence Rate - the frequency with which new cases of illness or disease occur in a population over a specified period of time. This rate is computed as the number of new cases of a disease occurring in a period of time (numerator) divided by the size of the population at risk of becoming a case during that period (denominator) for 1,000 or 100,000 people.

Incidence Rate, Age-Adjusted - controls for the effects of differences in a population’s age distribution. When comparing across geographic areas or time, age-adjusting is typically used to control for the influence that different population age distributions might have on health event rates. Direct age-adjustment weights the age-specific rates observed in a population by the proportion of each age group in a standard population.

Indicator - a quantifiable measure that indicates the status or condition of a topic area for a defined group for a defined time interval.  Indicators are often used to establish a baseline and track progress toward improvement goals.

Indoor Air Pollution - air pollutants that occur within buildings or other enclosed spaces, as opposed to those occurring in outdoor air. Some examples of indoor air pollutants are nitrogen oxides, wood smoke, asbestos, formaldehyde, and carbon monoxide.

Infant Mortality - death of a child younger than one year of age. These deaths are often divided into two groupings: neonatal mortality (death of an infant within the first 27 days of life) and post-neonatal mortality (death of an infant 28 – 364 days old).

Infant Mortality Rate - the number of children in a population who die before their first birthday divided by the number of live births in that population during the same time interval.

International Classification of Diseases (ICD) - diagnostic codes developed and maintained by the World Health Organization (WHO) to classify diseases and signs, symptoms, abnormal findings, complaints, social circumstances and causes of injury or disease. Usually referred to by version number, as in ICD-9 or ICD-10. More info:  https://www.cdc.gov/nchs/icd/icd9cm.htm#:~:text=ICD%2D9%2DCM%20is%20the,10%20for%20mortality%20coding%20started.

Invasive (with respect to cancer) - malignant cancers that have spread from their point of origin when initially diagnosed.

Known Human Carcinogen – a compound for which sufficient evidence exists in epidemiological studies to support a causal association between exposure and cancer.

Lead (Pb) – a natural occurring element and heavy metal found in the earth’s crust. Lead exposure can increase a person’s risk for a range of health issues, including damaging effects to the brain, nervous systems, kidneys, and blood cells.

Leukemia - cancer of the blood or bone marrow, characterized by an abnormal proliferation (production by multiplication) of blood cells, usually white blood cells. Leukemia is a broad term covering a spectrum of cancers.

Likelihood – the chance of something happening.

Low Birth Weight - A baby born with a weight less than 2,500 grams (approximately 5.5 pounds).

Maximum Contaminant Level (MCL) - an enforceable federal water quality standard for a particular substance (such as arsenic, benzene, lead) that the USEPA considers practically and feasibly attainable. In many cases, the MCL is equivalent to the Maximum Contaminant Level Goal (MCLG) established by the USEPA as a non-enforceable public health objective. For carcinogenic contaminants, however, the USEPA determined that it is most likely impossible to completely eliminate the contaminant but does not set an MCL at "zero." Rather, the USEPA sets a level that can be attained, given available technology and resources.

Measure - a quantitative way of determining the magnitude of an indicator for comparison.

Median – the middle value of a distribution above and below which lie an equal number of individual values; a midpoint.

mg/L - milligrams per Liter.

Microgram (µg) - one millionth of a gram (about 3.53 x 10^-8 ounces).

Micrometer (µm, also referred to as micron) - one millionth of a meter (about 3.94 x 10^-5 inches).

Mobile Source - a source of air pollution that moves, such as automobiles, motorcycles, trucks, off-road vehicles, boats, and airplanes.

Mortality - a fatal outcome; death.

Mortality Rate - the number of deaths in a specific population during a specific time interval divided by the size of the population during that same period of time.  The result is often multiplied by a base number, such as 1,000 or 100,000 so that the resulting rate is the number of deaths per 1,000 or 100,000 people.

Municipality - a city, town, or other jurisdiction which typically has its own local government. In New Jersey, as of March 2022, there are 564 municipalities.

Myocardial Infarction (MI, also known as AMI for acute myocardial infarction, and commonly called heart attack) - occurs when blood flow to a section of heart muscle is blocked.

National Ambient Air Quality Standards (NAAQS) – federal air quality standards established by the EPA for six “criteria” pollutants commonly found in outdoor air. EPA calls these pollutants "criteria" air pollutants and regulates them by developing science-based human health (primary) and/or environmental (secondary) standards for setting permissible levels.  More info: https://www.epa.gov/naaqs . 

Natural Sources – non-manmade emission sources, including biological and geological sources, wildfires, and windblown dust.

Neonatal Mortality - death in the first 28 days of life. The leading causes of neonatal deaths are birth defects, disorders due to prematurity and low birth weight, and pregnancy complications.

New Jersey State Health Assessment Data (NJ SHAD) System - a data system maintained by the New Jersey Department of Health which provides access to non-confidential public health indicators, datasets, and information on the health status of New Jerseyans.  More info: https://www-doh.state.nj.us/doh-shad/home/Welcome.html.

Nitrates - compounds of nitrogen and oxygen that can pollute drinking water from contaminated or failing septic tanks or nitrogen-based fertilizer run-off. Once taken into the body, nitrates are converted into nitrites. High nitrate levels in drinking water are a health risk to infants, children, and adults.

Nitric Oxide (NO) - a gas formed by combustion under high temperature and high pressure in an internal combustion engine.  NO is converted by sunlight and photochemical processes in ambient air to nitrogen oxide (NO₂) and is a precursor of ground-level ozone formation.

Nitrogen Dioxide (NO₂) - the result of nitric oxide combining with oxygen in the atmosphere; major precursor of ground-level ozone formation.

Nonattainment area - a geographic area in which the level of a criteria air pollutant persistently exceeds the levels established by the National Ambient Air Quality Standards (NAAQS).

Nonpoint source - diffuse contamination of water that does not originate from a single discrete source (for example excess fertilizers, herbicides and insecticides from agriculture or residential areas).

Numerator - the upper portion of a fraction used to calculate a rate or ratio.

Ozone (O₃) – a highly reactive gas composed of three oxygen atoms. It is both a natural and a man-made product that occurs in the Earth's upper (stratosphere) and lower (the troposphere) atmospheres.  While ozone in the stratosphere provides protection from the sun’s ultraviolet rays, ozone in the troposphere (also called ground-level ozone) is formed through a chemical reaction between nitrogen oxide and volatile organic compounds (VOCs) and is harmful to public health and welfare. Ozone is one of the six pollutants regulated with a National Ambient Air Quality Standard.

Oxides of Nitrogen (NO_x) - the result of photochemical reactions of nitric oxide in ambient air and a major precursor of ground-level ozone formation and acid rain. NO_x are a product of combustion from transportation and stationary sources and are harmful to the lungs, aggravating asthmatic symptoms.

Part per billion (ppb) – a unit of measurement commonly used to express a concentration ratio, as in establishing the maximum permissible amount of a contaminant in water, land, or air. Ppb is the number of units of mass of a contaminate per 1billion units of total mass.

Part per million (ppm) – a unit of measurement commonly used to express a concentration ratio, as in establishing the maximum permissible amount of a contaminant in water, land, or air. Ppm is the number of units of mass of a contaminate per 1 million units of total mass.

Particulates - fine liquid or solid particles such as dust, smoke, mist, fumes, or smog that vary in size, shape, density and electrical charge. See PM₁₀ and PM_2.5.

Pb – abbreviation for the element lead.

pCi/L – picocuries per liter.

Precursor - a compound that participates in a chemical reaction that produces another compound.

PM - Particulate Matter. See PM₁₀ and PM_2.5.

PM₁₀ - particulate matter less than10 micrograms (µg) in diameter which can deposit in upper (larger) air passages in the lungs. PM₁₀ is one of the “criteria” pollutants regulated by a National Ambient Air Quality Standard.

PM_2.5 (also referred to as fine particulate matter) - particulate matter less than 2.5 micrometers (μm) in diameter which can deposit in lower (smaller) air passages in the lungs and even reach the bloodstream. PM_2.5 is one of the “criteria” pollutants regulated by a National Ambient Air Quality Standard.

Point Source – a discrete item from which pollutants are discharged (for example pipes, conduits, wells, smokestacks).

Population Density – a measurement of population per unit area (for example 100 people living within a square mile).

Possible Human Carcinogen – a compound for which there exists limited evidence from animal studies but inadequate or no evidence from human studies to support a causal association between exposure and cancer.

Post Neonatal Mortality - death occurring from one month of age until the first birthday. The leading causes of post neonatal morality include sudden infant death syndrome (SIDS), birth defects, and injuries.

Preterm Birth - a gestation period of less than 37 weeks.

Primary Standard - a pollution limit set by the EPA for a criteria pollutant that is based on human health effects.

Private Well Testing Act (PWTA) - a New Jersey consumer information law that the requires testing and disclosure of water quality during real estate transactions on properties with potable private wells. It requires that landlords test well water for rental properties once every five years. More info: https://www.state.nj.us/dep/watersupply/pw_pwta.html.     

Poverty - thresholds established by the U.S. Census Bureau and determined by pre-tax income excluding capital gains and non-cash benefits such as food stamps that vary by family size and composition. New Jersey further defines poverty as at or below twice the poverty threshold determined by the United States Census Bureau.

Probable Human Carcinogen – a compound for which there exists limited evidence in epidemiological studies and/or sufficient evidence from animal studies to support a causal association between exposure and cancer.

Public Water Systems - provide piped water for human consumption to at least 15 service connections or regularly serve 25 individuals. Community water systems are one kind of public system. All public water systems are subject to government regulation for testing and treatment of contaminants.

Query – a search for data. 

Race (or racial group) - usually refers to the categorization of humans into populations or ancestral groups based on various characteristics.  In terms of health statistics, race generally refers to whether a person is American Indian/Alaskan Native, Asian, Black/African American, Native Hawaiian/Other Pacific Islander, White, or multiple races.

Radon - an invisible, odorless, and tasteless radioactive gas that comes from the breakdown of naturally occurring uranium in soil and rock. Radon can enter homes through openings that are in contact with the ground, such as cracks in foundations, small openings around pipes, and sump pits.

Rate - a measure of new events or occurrences in a population.  The crude rate is calculated as the number of events per time interval divided by the total number of people in the population in the same time interval.

Risk - the chance or probability that a person will be harmed or experience an adverse health effect if exposed to a hazard. It may also apply to situations with property or harmful effects on the environment.

Safe Drinking Water Act (SDWA) - a U.S. federal law that regulates the Nation’s drinking water supply.  More info: https://www.epa.gov/dwreginfo/drinking-water-regulations.                

Secondary standard - a pollution limit set by the EPA for a criteria pollutant that is based on environmental effects such as damage to property, plants, and visibility.

Sex Ratio - the ratio of male to female births.

Singleton - a child born from a pregnancy with a single fetus.

Smoke - created when air combines with the airborne solid and liquid particulate matter, and gases that are emitted when a material undergoes combustion.

Statistically Significant – when the difference between two rates would have occurred by chance less than five times out of 100.  If a difference is statistically significant, it is not likely due to random chance.

Suppression - a statistical method used to report aggregate health data in tables that restricts the release of certain data to protect the identity and privacy of individuals and to avoid the risk of identification of individuals in small population groups.  A suppression rule generally applies only to health data and not environmental data. Different datasets (for example state cancer registry data versus inpatient hospitalization data) use a variety of suppression rules when making non-confidential aggregate data publicly available.    

Surveillance - the ongoing, systematic collection, analysis, tracking, and interpretation of health outcomes which is essential to the planning, implementation, and evaluation of public health.   

Tracking - another word for surveillance and monitoring.

Trihalomethanes (THMs) – a family of disinfection byproducts formed when disinfectants such as chlorine, used to control disease-causing contaminants in drinking water, react with naturally occurring organic matter in the source water.  The primary trihalomethanes of concern are chloroform, dibromochloromethane, bromodichloromethane, and bromoform.

Total Trihalomethanes (TTHMs) - the total amount of trihalomethanes allowed by the EPA in drinking water.

Turbidity - cloudiness or haziness of a fluid caused by large numbers of individual particles that are generally invisible to the naked eye.  The measurement of turbidity is a key test of water quality.

Very Low Birth Weight - a birth weight less than 1,500 grams (approximately 3 pounds 5 ounces).

Very Pre-term Birth - a gestational period less than 32 weeks.

Violation - an activity or an existing condition that does not comply with an environmental law or regulation.

Volatile organic compounds (VOCs) - substances containing carbon and various proportions of other elements, such as hydrogen, oxygen, fluorine, chlorine, bromine, sulfur, and nitrogen that can easily become vapors or gases.  VOCs are commonly found in gasoline, solvents, oil-based paints and inks, and consumer products, such as aerosol spray products.  VOCs react with nitrogen oxides, sunlight, and heat to form ground-level ozone.  Many VOCs are also considered air toxics.

Water Contaminant - a potentially harmful substance that is present in water, resulting from either a biological process or from point source or non-point source pollution.