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Surface Water and Sediment

Characteristics

Surface Water

• Discussion restricted to freshwater

• Lentic and Lotic systems

Lentic Systems• Lakes

• Ponds

• Impoundments

• Basins

• Oxbows

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Lentic Systems

• Shoreline pools and mudflats

Lentic Systems• Open water areas of

wetlands

• Bog and fen wetlands– A bog

• a wetland that accumulates peat, a deposit of dead plant material—often mosses, and in a

majority of cases, sphagnum moss

• Acidic water chemistry

– Fens• a wetland usually fed by mineral-rich surface

water or groundwater.

• pH neutral or alkaline water chemistry, with

relatively high dissolved mineral levels but few other plant nutrients.

• They are usually dominated by grasses and sedges, and typically have brown mosses

Lentic Systems

• natural and man-made

• depth varies considerably

3

Lotic Systems

• rivers

• streams

• creeks and

brooks

• ditches

• drainageways

Lotic Systems

• mid-sized rivers have pool and riffle

complexes that alternate, runs and glides

also

• mid-sized and larger rivers meander within

their floodplain, unless ‘managed’ by man

Water Quality

• lentic: oligotrophic vs

eutrophic

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Water Quality

• lotic: head waters

versus downstream

areas

Water Quality

• Relationship to groundwater

– Discharge and recharge

• Water column is location of plankton and

nekton communities

• Chemical characteristics, physical

characteristics, and biological diversity are

indicators of water quality

Water Quality

• Possible contaminants are many:

– metals

– VOCs, SVOCs

– GROs and DROs, oil and grease

– pesticides

– pathogens

– invasive species

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Water Quality – Sampling Considerations

• Lentic systems

tend to be

heterogeneous

vertically and

horizontally

– thermocline

– weight of

contaminants

– zones based

on inflow

Water Quality – Sampling Considerations

• Lotic systems tend to be

more homogeneous

– vertically but not

necessarily horizontally

– except for large rivers

which take on some

characteristics of lentic

systems

• Both lotic and lentic vary

temporally

Sediments

• The ‘bottom’ of lentic and lotic systems

• Rock, sand, silts, detritus, clayey

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Sediments

• Depositional areas

around curves and

slow moving pool

areas tend to

accumulate

sediments, scouring

areas lose

Sediment Quality

The result of

deposition from

the ‘water

column,’

underlying

geology, and

biological

activity

Sediment Quality

• Deposition sources

include materials of

– Biological origin

– Urban stormwater run

off

– Industrial and

municipal discharge

– Erosional materials

• Heavier substances

accumulate

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Sediment Quality

• Location of a community of ‘benthic’

organisms:

– periphyton

– bacteria

– fungi

– microscopic worms

– macroinvertebrates

– fish

Sediment Quality

Sediments are both dynamic and historic

• upper layers subject to resuspension

• lower layers tend to stay put and reveal history of deposition

• temporal variation less than surface water

Why Sample?

• Determine ‘use’

– Chemical characteristics

– Biologic communities

– Available habitat

• Characterize water quality

• Support permit applications

• Locate and delineate pollution release

and/or impact

• Monitor clean up activities

• Other reasons?

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Sampling Methods

• Surface waters

– Direct filling of sample

bottle

– Dipper

– Stainless steel bucket

– Bottle sampler

– Kemmerer and Van

Dorn samplers

Sampling Methods

Sediment Surfaces

• Ponar and Eckman

dredges

– tend to stir up the

bottom that may result

in some loss of fines

from sample

– takes 1-3 l of sample

depending on size

Sampling Methods

Sediment

Surfaces

• Ponar and

Eckman

dredges

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Sampling Methods

Sediment coring devices

• maintains sediment layering of inner core

• takes up to 1.5 l of sample

Decontamination

• Soap and water scrub (alconox and brushes, container)

• Water rinse

• Rinses in acid and/or solvent followed by water rinse

• Deionized water rinse

• Protect against recontamination between sites

• Rinse in site water at next site

Sample PreservationCertain parameters done in the field

• likely to change upon collection

– Temp, DO, pH, conductivity, flow, turbidity

Preservation needs: a function of analyte and analytical method

Field preparation

• Addition of fixatives

• Addition of stablizers

• Addition of dechlorinators

• Filtration followed by addition of stabilizers

• Cooling

• Freezing, uncommon

Lab preparation

• More filtering or fixation may be needed

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Drinking Water

Sources

• Potable Wells

• Raw influent water

• Finished water before leaving plant

• Finished water arriving at tap – required

surveillance for PWS

SamplingFirst draw samples

• Water has been sitting in plumbing

• Possible lead and copper leaching from delivery lines and fixtures

Flushed system

• Measures contaminants in finished water and those picked up on the way to the tap

– VOCs

– Bacteria – coliforms

– Pesticides and other organics

Stormwater

Requirement for “facilities who (1) discharge

to waters of the United States or a

separate municipal sewer system and (2)

engage in industrial activities, including

construction activity of over 5 acres of

land”

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Stormwater

First Flush

• Initial runoff from a site/catchment

following the start of a rainfall event

• As runoff travels over a catchment it will

pick up or dissolve pollutants and the "first

flush" portion of the flow may be the most

contaminated as a result

Effluents and Instream Samples

for Toxicity Tests

Point sources

• Require regular periodic sampling for

toxicity-based on permit requirements and

compliance history

• Industrial discharge

• Municipal discharge

Effluents – Sampling Locations

Final effluent

• End of pipe at or near

discharge point into

water way or entry

into sewer system

• Point before end of

pipe that provides

safer access

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Effluents – Sampling Locations

Final effluent

• Manway

• Flume

Effluents – Sampling

Locations• Pre or post

chlorination

Dechlorination Point at WWTP

Sodium Thiosulfate

Sprayers

Purpose for Sampling

1. Provide samples to initiate laboratory

toxicity tests

2. Analytical laboratory samples for

– conventional pollutants

– priority pollutants

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Collecting Samples for Toxicity

Tests - Effluent

• Almost always a

composite sample

using an automatic

sampling device

– 24-hour time

composite very

common

– flow proportional

composite may be

called for

Collecting Samples for Toxicity

Tests - Effluent• Chlorinated effluent

– collect before the point of chlorination

if possible

– in some cases, the

chlorinated/dechlorinated sample is

taken at the outfall

• Keep samples cool during

collection

• All samples to be collected with

no headspace

• Completed samples may be

transferred to suitable container

for shipment Refrigerated sampler

Collecting Samples for Toxicity

Tests - Effluent

• Effluent toxicity

analysis - sample into

Cubitainers® -

“industry standard”

– One-gallon (typical)

polyethylene plastic

collapsible containers

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Collecting Samples for Toxicity

Tests - Effluent

Volume needed

• Varies - one gallon typical

– more or less depending on type of test to be performed

• Acute test - single sampling event

• Chronic test - three sampling events in seven-day period

Collecting Samples for Toxicity

Tests – Supporting Samples

Upstream or Up-Current

• Grab outside of the zone of influence

• Wade and fill Cubitainers directly

• Serves as diluent or simple background

control in testing

• Volume needed depends on use in test

Collecting Samples for Toxicity

Tests – Supporting Samples

Near-field down-

current sample

Submerged outfall sampled

just before entry

Far-field down-current

grab

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Collecting Samples for Toxicity

Tests – Supporting Samples

Near-field down-current sample

• A grab within the mixing zone

• collected in the middle of the effluent plume– five times the water depth at the point of discharge down-

current or if the water is greater than 4 feet deep, 20 feet down-current from the outfall

• effluent plume determined by temperature, conductivity, visual observation, dye study or other method

• No acute toxicity allowed here

Collecting Samples for Toxicity

Tests – Supporting Samples

Far-field downcurrent grab

• Represents complete mixing of effluent with receiving water

– if rapid and complete mixing, collect midstream at distance five times the width at the point of discharge

– if mixing is not rapid and complete, collect mid-plume down current from the outfall at a point five times the stream width at the point of discharge

• for big rivers 2,500 feet down current

– boat may be needed

• document effluent plume as before

• No chronic toxicity allowed here