Role of Bio Markers In Water Monitoring

Biomonitoring Biological monitoring, or biomonitoring is the use of biological responses to

assess changes in the environment generally changes due to anthropogenic causes.

Biomonitoring programs may be qualitative, semi-quantitative, or quantitative.Biomonitoring is

a valuable assessment tool that is receiving increased use in water quality monitoring programs

of all types.

Biomarkers Biomarkers are species, populations or groups of species, which due to their

variability (biochemical physiological, ethological or ecological) allow the description of an

ecosystem status and reveal as early as possible, the natural or anthropogenic modifications

thereof

Types of Biomonitoring Surveillance before and after a project is complete or before and after a

toxic substance enters the water. The other type of biomonitoring is to ensure compliance with

regulations or guidelines or to ensure water quality is maintained.

Biomonitoring involves the use of indicators, indicator species or indicator communities

Benthic macroinvertebrates

Fish

Algae

Aquatic plants

Sentinel organisms:

Sentinel organisms, or indicator species that accumulate pollutants in their tissues from the

surrounding environment or from food, are important biomonitoring devices

Extreme Uptake

Barnacles Zinc (Zn) Bivalve mollusks Copper (Cu), iron (Fe) manganese Gastropod mollusks

Cu, Zn Isopods, amphipods Cu, Fe, Pb, Zn Polychaetes Cu

Moderate Uptake

Macroalgae (seaweeds) Most metals Mussels other bivalves Metals, metallothioneins

Polychaetes Cadmium (Cd), Pb Decapods (crayfish) Cd, Pb Finfish Cd, Pb

Assessment Assessment

It involves the monitoring of indicators and behavioral changes of organisms.Indicators must

display a biochemical genetic morphological or physiological change. Behavioral indices are

determined by particular species, populations dynamics or community changes.

Levels and Associated Biomonitoring

Measures Individual Genetic mutations Reproductive success Physiology Metabolism Oxygen

consumption Photosynthesis rate Enzyme/protein activation/inhibition Hormones (growth and

development) Disease resistance Tissue/organ damage Bioaccumulation

Population Survival rate or mortality Sex ratio Abundance/biomass Behavior (migration)

Predation rates Population decline/increase

Community Abundance of an organism or organisms

Biomass Density of an organism or organisms Richness (variety) Number of species size classes,

or other functional groups per unit area or volume or per number of individuals

Common Organisms used for Biomonitoring

Invertebrate indicators Increased ratio of aquatic worms (oligochaetes)

Increased ratio of midges (chironomids)

Increase of herbivorous mayflies (ephemeropterans)

Loss of snails, clams, mussels, daphnids, mayflies, midges

Algae

Algal growth is dependent on sunlight and nutrient concentrations. An abundance of algae is

indicative of nutrient pollution Algae are sensitive to some pollutants at levels which may not

visibly affect other organisms in the short term or may affect other communities at higher

concentrations.

Advantages of Algae

Algae have very short life cycles and rapid reproduction. This can also be a disadvantage. Algae

tend to be most directly affected by physical and chemical environmental factors. Sampling is

easy and inexpensive, requires few people and minimally impacts other organisms. Standard

methods exist.

Benthic macroinvertebrates Advantages

Benthic macroinvertebrates are found in most aquatic habitats. There are a large number of

species, and different stresses produce different macroinvertebrate communities Small order

streams often do not support fish but do support extensive macroinvertebrate communities.

Macroinvertebrates generally have limited mobility.Thus they are indicators of localized

environmental conditions. Since benthic macroinvertebrates retain (bioaccumulate) toxic

substances, chemical analysis will allow detection in them where levels are undetectable in the

water resource.

A biologist experienced in macroinvertebrate identification will, be able to determine relatively

quickly whether the environment has been degraded by identifying changes in the benthic

community structure of the water resource. Benthic macroinvertebrates are small enough to be

easily collected and identified. Sampling of macroinvertebrates under a rapid assessment

protocol is easy, requires few people and minimal equipment, and does not adversely affect other

organisms. Macroinvertebrates are the primary food source for recreationally and commercially

important fish.

Disadvantages

Benthic macroinvertebrates do not respond to all impacts. Seasonal variations may prevent

comparisons of samples taken in different seasons. Drifting may bring benthic

macroinvertebrates into waters in which they would not normally occur. Knowledge of drifting

behavior of certain species can alleviate this disadvantage. Certain groups are difficult to

identify to the species level.

Fish

Certain fish species such as salmon, trout, perch and sculpins, are less tolerant of pollution than

others. Bottom dwellers are more tolerant of organic pollution since they are adapted to lower

oxygen levels. Predatory species that use sight to hunt, such as pike, are sensitive to turbid

conditions

Fish Advantages

Fish are good indicators of long-term effects (several years) and habitat conditions. Fish

communities represent a variety of trophic levels; toxic substances tend to biomagnify, and thus

fish community structure reflects community health. Fish are consumed by humans. Fish are

relatively easy to collect and identify. Environmental requirements, life history information and

distribution are well known for most species.

Disadvantages

Motility and migration cause difficulty in pinpointing a pollutant as the cause of abnormalities

in individuals or a population. Monitoring only certain fish species will miss changes in the

benthic community or in other species in the community that over time will affect the fish

species. Fish are not as sensitive as their food (macroinvertebrates) to pollution and monitoring

of fish may not reflect severe changes in the invertebrate community. An assessment of fish

alone will not ensure ecosystem health.

Sampling Techniques

Kick seine

Requires 2 or more people.One person places a four by four feet nylon mesh screen seine is

placed along the bottom at an angle that will allow riffle areas to be easily sampled for benthic

macroinvertebrates. Another individual kicks the stream bottom down to 2 inches to loosen

macroinvertebrates for collection upstream of the net.The net is then removed from the water and

organisms are classified

Sweep nets

Used to sample invertebrates from the water column as well as communities attached to wetland

plants. The nets are at the end of a pole which is placed on the bottom of the water body and

swept up vertically through the water column or swept a standard length of vegetation.

Dredges or core samplers

A specified area is enclosed and sediments and the associated organisms are retrieved. Fast

moving organisms can and do escape. Core samplers are particularly useful in wetlands that are

dry.

Artificial substrates

Plastic plants or other sterile surfaces allow objective sampling and sample collection in

locations that are difficult to sample.Such artificial substrates should remain in place for at least a

month and the average is 8 weeks.

Emergence traps and funnel traps

Nets or funnels placed at or just above the water surface trap adult aquatic insects emerging from

the water.These will not collect benthic organisms such as aquatic worms and snails

Sampling Techniques Sampling time considerations include migration spawning and dispersal.

Nighttime sampling is suggested particularly for catfish and perch.

Electrofishing

A technique which stuns fish allowing them to be caught identified measured and released

quickly. Permits are required. Water body inlets and outlets can be blocked with nets to prevent

fish from escaping the electrical field

Seines Nets

pulled through the water to capture fish.Seines can allow an estimate of species richness. A

mesh size of 1/8 is recommended for fish