PRACTICES ARE CLOSELY
TIED TO THE CENTERPIECE
OF THIS WHOLE
WATER QUALITY PUZZLE...
POLLUTANTS.
SOME WATER POLLUTANTS ARE
EASY TO SEE, LIKE GARBAGE,
BUT THE MOST SERIOUS POLLUTION
PROBLEMS AREN'T AS OBVIOUS:
SEDIMENT, NUTRIENTS,
CHEMICALS, PATHOGENS.
SEDIMENT IS SIMPLY SOIL.
IT'S A VALUABLE RESOURCE
IN A FARM FIELD OR
ALONG A STREAM BANK,
BUT IT BECOMES A MAJOR PROBLEM
WHEN IT'S WASHED INTO WATERWAYS.
AT THE ROOT OF
THE PROBLEM IS EROSION.
>> EROSION OFF OF FARM FIELDS,
CONSTRUCTION SITES
WHERE YOU DON'T HAVE
PROPER SEDIMENT CONTROL
STRUCTURES IN PLACE,
YOU CAN EASILY HAVE
SEDIMENT ERODED OFF
THOSE LANDSCAPE AREAS.
YOU CAN HAVE PASTURE AREAS
THAT ARE OVERGRAZED.
ANIMAL ACCESS, CATTLE ACCESS
DIRECTLY TO STREAMS
WITH ALL THE TRAMPLING
ALONG A STREAM CORRIDOR,
THAT EXPOSES BARE GROUND,
WHICH IN TURN EXPOSES
SEDIMENT TO EROSION.
ALONG ALL OF OUR MAJOR RIVERS,
IF YOU DON'T HAVE
A LOT OF VEGETATION
SORT OF HOLDING
THE SOIL IN PLACE,
STREAM BANKS CAN BE
A MAJOR SOURCE OF SEDIMENT.
>> WHY IS SOIL SO DAMAGING
WHEN IT'S IN WATER?
IT AFFECTS EVERYTHING
FROM THE WAY WATER LOOKS
TO WHAT CAN LIVE IN IT.
SEDIMENT CAN BLOCK SUNLIGHT,
INFLUENCING WHAT TYPES OF
VEGETATION AND SPECIES
CAN THRIVE IN THAT WATER.
SEDIMENT FILLS IN WATERWAYS,
AFFECTING TRANSPORTATION
AND RECREATION,
AND SEDIMENT CAN BE A CARRIER
FOR OTHER POLLUTANTS,
LIKE TOXIC CHEMICALS
WHICH ATTACH TO THE SEDIMENT,
MAKING IT A DOUBLE THREAT.
NEXT ARE NUTRIENTS, WHICH POSE
AN ENTIRELY DIFFERENT PROBLEM.
NITROGEN AND PHOSPHOROUS
ARE NATURAL COMPONENTS OF
MANURE, HUMAN SEWAGE,
AND DECAYING ORGANIC
MATTER LIKE LEAVES.
THEY'RE ALSO PRESENT
IN MANUFACTURED FERTILIZERS.
NUTRIENTS ARE APPLIED TO
FARM FIELDS TO FEED CROPS
AND TO BACKYARD GARDENS.
THEY'RE USED TO GREEN UP
GOLF COURSES AND LAWNS.
THEY BECOME A PROBLEM WHEN
PRECIPITATION WASHES NUTRIENTS
OFF THE LAND AND INTO WATERWAYS.
ONCE THEY'RE IN WATER,
THEY DO WHAT THEY DO ON LAND...
ENHANCE PLANT GROWTH.
>> WHEN WE HAVE TOO MUCH
NITROGEN IN THE WATER,
YOUR WATER TENDS TO TURN GREEN
AND YOU GET A LOT
OF ALGAE BLOOMS.
WHEN THOSE ALGAE BLOOMS FINALLY
DIE AND START TO DECOMPOSE,
THEY TAKE UP ALL THE
OXYGEN IN THE WATER,
SO THERE'S A LOW AMOUNT OF
OXYGEN IN THE WATER,
WHICH CAUSES PROBLEMS
FOR FISH AND PLANTS
BECAUSE THEY NEED THAT OXYGEN.
>> NUTRIENTS AREN'T JUST
DAMAGING TO WATER ECOSYSTEMS;
THEY POSE A REAL RISK TO HUMANS.
NITRATES,
A BYPRODUCT OF NITROGEN,
ARE ESPECIALLY DANGEROUS.
>> WHEN WE HAVE TOO MUCH
NITROGEN IN DRINKING WATER,
BABIES UNDER SIX MONTHS OF AGE
CAN DEVELOP SOMETHING CALLED
BLUE BABY SYNDROME.
THEIR BLOOD CAN'T
CARRY ENOUGH OXYGEN,
AND THAT CAN CAUSE
SOME HEALTH PROBLEMS.
WE MAY HAVE OLDER PEOPLE OR
PEOPLE WHO ARE IN POOR HEALTH
THAT CAN ALSO HAVE THAT PROBLEM.
>> THE RISK IS SO SERIOUS
THAT THE ENVIRONMENTAL
PROTECTION AGENCY, EPA,
TIGHTLY REGULATES THE LEVELS
ALLOWED IN DRINKING WATER.
CHEMICALS ARE ANOTHER
CLASS OF POLLUTANTS.
SOME CHEMICALS COMMONLY
USED IN MANUFACTURING
-- MERCURY, PCBs, LEAD --
ARE TOXIC TO THE
ENVIRONMENT AND HUMANS
WHEN THEY REACH CERTAIN LEVELS.
BECAUSE OF THE HEALTH RISKS
THESE CHEMICALS POSE,
THE EPA CAREFULLY REGULATES
INDUSTRIAL WASTE.
SPECIAL PERMITS GOVERN THE
DISPOSAL OF TOXIC CHEMICALS,
BUT SPILLS, ACCIDENTS,
AND IMPROPER DISPOSAL
MEAN THEY STILL
GET INTO WATERWAYS.
THE PROBLEM ISN'T JUST
INDUSTRIAL EITHER.
THINK OF THE TOXINS
AROUND YOUR OWN HOUSE...
CLEANERS, PAINT THINNERS,
PESTICIDES, OIL.
IMPROPER DISPOSAL
OF JUST ONE GALLON OF OIL
CAN IMPAIR 250,000
GALLONS OF WATER,
ABOUT THE AMOUNT OF WATER
IN THIS POOL.
AGRICULTURE ALSO RELIES
HEAVILY ON CHEMICALS LIKE
HERBICIDES AND PESTICIDES.
THEIR APPLICATION NEEDS TO BE
CAREFULLY CONTROLLED TO PREVENT
CONTAMINATION OF WATER.
THE LIST OF CHEMICALS WE USE
EVERY DAY HAS GROWN FASTER THAN
OUR KNOWLEDGE OF HOW THEY
INTERACT WITH THE ENVIRONMENT.
EMERGING CONTAMINANTS,
A BUZZWORD IN WATER CIRCLES,
LOOKS AT CHEMICALS NOT
TRADITIONALLY TRACKED,
LIKE CAFFEINE,
OVER-THE-COUNTER DRUGS,
ANTIBIOTICS, AND DISINFECTANTS.
A STUDY COMPLETED BY THE
UNITED STATES GEOLOGICAL SURVEY
FOUND LEVELS OF MANY OF
THESE CONTAMINANTS
IN STREAMS ACROSS
THE UNITED STATES.
NOW THE REAL WORK BEGINS
TO SEE WHAT, IF ANY, EFFECTS
THESE CHEMICALS
HAVE ON WATER QUALITY.
PATHOGENS ARE PROBABLY THE MOST
SERIOUS THREAT TO OUR HEALTH.
PATHOGENS ARE DISEASE-CAUSING
BACTERIA AND VIRUSES.
THEY CAN COME FROM HUMAN SEWAGE
OR RAW ANIMAL WASTE.
IF PATHOGENS CONTAMINATE WATER
AND AREN'T ELIMINATED
DURING TREATMENT,
THE TINY ORGANISMS CAN KILL.
>> ONE OF THE REAL RISKS
THAT ANYBODY FACES
WHO TREATS WATER EITHER
TO DRINK OR, AS WE DO,
TO MAKE IN A CONDITION THAT
CAN BE RETURNED TO THE RIVER
SO FISH AND WILDLIFE CAN USE IT
AND OTHER PEOPLE CAN DRINK IT,
IS KILLING CERTAIN KINDS OF
VIRAL INFECTIONS OR BACTERIA.
