Environmental Monitoring Midterms

Terms and Definitions

Environmental monitoring

Observation and study of the environment, including the systematic collection of samples from air, water, soil, and biota to understand environmental conditions and support decisions.

UNECE definition of environmental monitoring

Gathering, assessing, and reporting environmental information through continuous or periodic sampling, observation, and analysis, covering natural variation, environmental changes, and human pressures.

Data → information → knowledge → decision

The main progression in environmental monitoring, where collected data are processed into information and knowledge that can guide decisions.

Physical, chemical, and biological parameters

Environmental assessment parameters considered when assessing environmental conditions.

Observation scale

The spatial or temporal scale selected according to the objective of the environmental observation.

Global

Spatial scale covering the Earth, generally more than 10,000 km.

Meso

Spatial scale covering a continent, country, or state, generally more than 100 km.

Intermediate

Spatial scale covering features such as watersheds, rivers, or lakes, generally more than 1 km.

Field

Spatial scale covering an agricultural field or waste site, generally more than 1 m.

Macro

Spatial scale involving animals, plants, or soil, generally more than 1 mm.

Micro

Spatial scale involving small particles, fungi, or bacteria, generally more than 1 μm.

Ultra-micro

Spatial scale involving viruses or molecules, generally more than 1 nm.

Atomic

Spatial scale involving atoms or subatomic particles, generally less than 1 nm.

Geologic

Temporal scale covering more than 10,000 years.

Generation-lifetime

Temporal scale covering approximately 20 to 100 years.

Annual

Temporal scale covering more than 1 year.

Seasonal

Temporal scale covering more than 4 months.

Daily

Temporal scale covering more than 24 hours.

Hourly

Temporal scale covering more than 60 minutes.

Instantaneous

A time scale representing a measurement taken at a particular moment.

Limited observation principle

Because everything cannot be observed everywhere and at all times, enough observations are collected and statistics are used to interpolate and predict the needed conditions.

Environmental heterogeneity

The condition in which environmental characteristics vary across both space and time, making sampling difficult.

Environmental sampling plan

A sampling plan that is careful, cost-effective, and capable of obtaining the most information possible from limited resources.

X-Y plane

The surface dimension of the environment used to study features such as mangrove forests, grasslands, wetlands, ponds, and lakes.

Z dimension

The depth or height dimension used to study the atmosphere upward and the subsurface downward.

Soil sampling

Sampling used to determine properties such as nutrient content.

Geological profiling

Examination of geological layers to study minerals, hazards, and protection requirements.

Atmospheric measurements

Measurements used to study weather conditions and pollutant transport.

Temporal environmental measurements

Measurements that may follow natural daytime, nighttime, seasonal, and yearly cycles or be taken at intervals of seconds, minutes, hours, weeks, or months.

Systematic sampling interval

Sampling performed at definite and predetermined time intervals.

Drinking-water potability test

A water-quality test usually conducted monthly according to the module.

Soil fertility test

A farmland soil test conducted at least once a year according to the module.

Sampling location

The place where environmental samples are collected, determined using statistical considerations about how many samples are needed and where they should be taken.

Random sampling

A sampling approach in which locations are selected randomly and each sampling unit has an equal chance of being chosen; the area may be subdivided when prior studies exist, producing a random data set.

Systematic sampling

A subset of random sampling in which the first location is selected randomly and subsequent locations follow a periodic pattern; it is useful for pollutant distribution maps, contour maps, hot spots, subsurface leaks, and hidden objects.

Grab / Search / Exploratory sampling

A haphazard pollution-monitoring approach in which only one or two samples may be taken, suitable mainly for preliminary investigation, such as measuring total volatile hydrocarbons at the soil surface to locate an underlying pollution source.

Surrogate sampling

A cost-cutting approach that measures one parameter to estimate another, such as estimating Na⁺ and Cl⁻ in soil using electrical conductivity or estimating TDS in water from EC.

Composite (Bulking) sampling

Mixing samples from several locations and/or time points into one representative sample to reduce analysis costs when spatial and temporal variation are not being studied; common in agriculture for average nutrient concentration and soil fertility.

Path Integrated sampling

An approach in which air components are analyzed using open-path infrared (IR) and ultraviolet (UV) spectroscopy.

Time Integrated sampling

Sampling commonly used at weather stations in which ambient-air properties such as wind speed and temperature are measured and reported as averages over a specified interval, such as hourly or daily.

Remote sensing

An approach that acquires a two-dimensional picture of Earth's surface by detecting electromagnetic radiation emitted from the surface.

Destructive sampling

Environmental sampling that removes a sample from its environment, affects environmental integrity, and often produces long-term or irreversible disturbance, such as geological core drilling or removing or sacrificing biological specimens.

Subsurface geologic cores

Destructive samples with major and permanent environmental damage.

Soil cores

Destructive samples causing minor but permanent damage.

Animals and Plants tissue samples

Destructive samples with variable damage that may be reversible.

Water and Air samples

Samples whose disturbance is considered insignificant and reversible.

Nondestructive sampling

Also called noninvasive sampling; uses technology to measure environmental conditions without physically isolating the sample from its environment.

Remote sensing as nondestructive sampling

Uses sensors to detect electromagnetic radiation at liquid-solid or gas-solid interfaces; satellite remote sensing can detect visible, IR, and UV light from Earth's surface.

Direct measurement

Nondestructive measurement using instruments such as electrodes to measure water-quality parameters including pH and EC.

Noninvasive-method caution

Even methods considered nondestructive or noninvasive can modify the environment; for example, electrodes used in geo-resistivity surveys can alter soil properties.

Contaminant

Any foreign substance present in another substance, including something present where it should not be or present at a concentration above the background level; its presence does not automatically mean it causes health effects.

Pollutant

A contaminant that reaches a level at which it begins to produce biological harm; it may be a substance, organism, or energy and can degrade ecosystems or compromise present or future uses.

Water quality parameters

Physical, chemical, biological, bacteriological, and radiological properties used to assess water quality, with selected parameters depending on the intended use of the water.

Ambient water standard

Philippine Clean Water Act of 2004, DENR DAO 2016-08, and DENR 2021-19 as references identified in the module for ambient water.

Drinking-water standard

DOH DAO 2017-10 and the Philippine National Standards for Drinking Water of 2017 as references identified in the module.

Effluent-water standard

DENR DAO 2016-08 and DENR 2021-19 as references identified in the module for effluent water.

Agricultural wastewater-for-reuse standard

DA DAO 2007-26, identified in the module as the relevant reference for agricultural wastewater intended for reuse.

Ambient water monitoring

Monitoring that covers rivers, streams, lakes, ponds, similar water bodies, and marine waters including coastal and offshore waters.

DENR

The agency identified under the Philippine Clean Water Act of 2004 as taking the lead in preparing and formulating water-quality standards; the module identifies DENR DAO 2016-08 and DENR 2021-19 as revisions to water-quality guidelines.

Primary water-quality parameters

Required minimum water-quality parameters for each water body.

Secondary water-quality parameters

Additional parameters used for baseline assessment, Environmental Impact Assessment, and other water-quality monitoring purposes; they are divided into inorganics, metals, and organics.

Inorganics, Metals, Organics

The three divisions of secondary water-quality parameters.

Biochemical Oxygen Demand (BOD)

The amount of oxygen needed by microorganisms to break down organic pollutants in water; measured in mg/L, and used to estimate domestic and industrial waste pollution strength and assess stream pollution at a specific time.

Carbonaceous Biochemical Oxygen Demand (CBOD)

The oxygen used when microorganisms break down carbonaceous organic molecules such as cellulose and sugars into CO₂ and water.

Nitrogenous Biochemical Oxygen Demand (NBOD)

Oxygen demand resulting from decomposition of nitrogenous compounds or proteins. Protein breakdown produces sugars and ammonia; ammonia is converted to nitrate, and nitrate creates an oxygen demand more than four times that associated with an equivalent amount of sugar.

BOD₅

BOD measured by determining oxygen consumption in a water sample at 20°C, in the dark, over a specified period, most commonly 5 days.

True

Increasing BOD means more oxygen is consumed by decomposition, causing dissolved oxygen to decrease.

Chloride

A water-quality parameter associated with dissolved natural salts; important chloride-containing salts include NaCl, KCl, and CaCl₂, and chloride is measured in mg/L.

Chlorides

______ are relatively unreactive and always present in sewage, they can serve as an indicator of fecal contamination in rivers and groundwater; when elevated may also indicate saltwater intrusion into freshwater bodies.

True color

Color produced by compounds dissolved in water; because the compounds are dissolved, the color is not easily removed by sedimentation. Sources may be natural or caused by human activities, such as dissolved products of plant biodegradation producing brownish water.

True color

______ is caused by dissolved compounds, remains after standing, is measured in Pt-Co, and is measured with a spectrophotometer.

Turbidity

______ is caused by suspended particles, can decrease when particles settle, is measured in NTU, and is measured with a turbidity meter or sometimes a Secchi disk.

Platinum-Cobalt units (Pt-Co)

Unit used to express true color in water.

455 nm

Wavelength identified in the module for true-color measurement using a spectrophotometer.

Turbidity

A measure of water clarity caused by suspended particles; high amounts of sediment and clay can make water murky, and is measured in NTU.

Nephelometric Turbidity Units (NTU)

Unit used to measure turbidity or the cloudiness caused by suspended particles in water.

Dissolved Oxygen (DO)

The amount of oxygen dissolved in water, measured in mg/L or percent saturation; oxygen is more soluble in cold water.

Percent oxygen saturation (%)

The amount of oxygen dissolved per liter of water relative to the maximum amount of oxygen that can dissolve at that temperature.

Fast-moving water

Water with greater aeration and more bubbles, usually resulting in greater oxygen input and higher DO.

Non-moving water

Water in which oxygen mostly enters the uppermost layer while deeper layers tend to have low DO because microorganisms decompose organic matter deposited at the bottom and consume oxygen.

Dams and diversion weirs

Structures that can lower DO downstream; water released from the top is usually warmer and has lower DO, while bottom-released water is colder but may still have deficient DO because of decomposition at the bottom.

Cooler or rainy months

Conditions generally associated with higher DO.

Summer/dry season

Season characterized by lower water flow and velocity, generally resulting in lower DO.

Rainy season

Season in which greater rainfall and water flow can increase aeration and bring oxygen from the air, generally increasing DO.

Bacteria and fungi

Organisms that decompose organic matter and consume dissolved oxygen.

Highly vegetated waters

Waters that can become oxygen supersaturated during the day because of photosynthesis but oxygen deficient at night because respiration continues without photosynthetic oxygen production.

Usually occurs in the late afternoon.

Highest DO level

True

Lower altitude has higher atmospheric pressure, which makes it easier for water to dissolve oxygen.

Dissolved and suspended solids

Lower concentrations of ______________ allow more oxygen to dissolve; freshwater generally has higher DO than saltwater, while high salt concentration from strong evaporation can also be associated with low DO.

Nitrate and phosphate

Important nutrients whose excess can stimulate algal growth and contribute to oxygen depletion.

Eutrophication

The process in which excess nutrients increase algae, algae die, bacteria decompose the algae and consume oxygen, causing DO to decrease and potentially producing fish kills.

Organic wastes

These are leaves, dead plants, dead animals, animal manure, and sewage that increase decomposition and oxygen consumption, thereby lowering DO; the size of the DO drop depends on the BOD of the organic material.

Riparian vegetation

Vegetation, especially trees beside a water body, that provides shade, lowers water temperature, and reduces the duration of high temperatures.

Groundwater inflow

Groundwater entering a stream generally has low oxygen and low temperature; it may initially lower stream DO, but its cooling effect can allow more oxygen to dissolve and improve oxygen-dissolving capacity.

8 mg/L DO

The approximate DO level or higher for unpolluted freshwater.

5 mg/L DO

An approximate DO concentration as sufficient for many aquatic organisms.

Horizontal DO variation

Spatial variation in DO commonly found in small, shallow, flowing streams.

Vertical DO stratification

Vertical differences in DO that can occur in larger water bodies.

Fecal coliform

Microscopic bacteria that passed through the intestines of warm-blooded animals; their presence can indicate fecal contamination and possible pathogenic microorganisms.