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.