Environmental Science ENSC 2800

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Environmental Science ENSC 2800

• Spring 2003
• General Topic 2
• Water Pollution in California

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Key Water Quality Concerns in California Rivers,
Streams, Lakes and Groundwater

• Toxic chemicals - carcinogens, persistent
  neurotoxins, endocrine disrupters (especially
  pesticides)
• Dissolved salts - chlorides, bromides, etc.
• Plant nutrients principally nitrogen and
  phosphorous
• Suspended sediments and other causes of increased
  turbidity
• Organic carbon - decaying plant substances
• Pathogenic organisms - especially
  cryptosporidium, bacteria
• Nitrogen as nitrates - sewage and fertilizer

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Spotlight on Toxic Chemicals

• A total of 304,424 pounds of carcinogens,
  persistent toxic metals and reproductive toxins
  were known to have been legally discharged into
  California waters in 1997 (from CA Water Plan
  1998).
• Indirect sources add even larger quantities of
  these, principally
• agricultural runoff and drift of pesticides,
• active and historical mine and mine tailing
  drainage,
• urban runoff and urban air pollution deposition,
• industrial and municipal waste discharge,
• oil refining gas distribution and storage
  system leaks and runoff.

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Examples of Toxic Hot Spots

• Uranium mining, weapons testing, and radioactive
  waste storage introduces alpha radiation into the
  Colorado River upstream of diversions to Southern
  California adds to background exposure and body
  load.
• Runoff from the Gambonini mine in Marin Co. can
  add as much as 100 of mercury in a rainy month
  to recipient streams and Tomales Bay (one of 50
  such mines along coastal range).
• Santa Monica - two aquifers had up to 610 ?g/l of
  MTBE - supplied 80 of Santa Monica's water but
  were shut down - State health agency says 14 ?g/l
  is healthy limit.
• caused by at least 43 LUSTS 2 leaky refinery
  pipes.
• had to buy surface water at a cost of 3.5
  million per year.

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Spotlight on Dissolved Salts

• Ocean intrusion - coastal aquifers and
  Sacramento/San Joaquin River Delta.
• Caused by over exploitation of water above
  hydrological and hydrogeological recharge
  potential.
• Point and non-point pollution - Central Valley,
  Southern California, esp. Colorado River Salton
  Sea.
• Caused by returning agriculture drainage water,
  runoff from irrigated fields, runoff from salted
  Sierra roads, wastewater discharge, backwash from
  water softeners.

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Dissolved Salt Hot Spots

• Example - Lower Colorado River has concentrations
  of 736 mg/l - CO water piped to Los Angeles has
  an average of 691 mg/l salt.
• TDS of 500 mg/l is the recommended limit for
  human consumption,
• Example - salt water intrusion to SF Delta brings
  bromides, leading to disinfection byproducts
  (e.g. bromates) known to be carcinogenic and/or
  contributors to miscarriages.
• Requires expensive desalination or supply of less
  salty water to blend and bring concentration down
  prior to use.

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Spotlight on Plant Nutrients

• Fertilizer runoff and human wastewater discharge
  release soluble and bioavailable nitrogen and
  phosphorous to water bodies.
• Algae and other microscopic organisms undergo
  abnormally high population growth process known
  as eutrophication.
• Creates problems of reduced visibility, reduced
  dissolved oxygen (when they die), increased
  temperatures, drinking water tastes and smells,
  disinfection byproducts (e.g. trihalomethanes),
  loss of aesthetics.
• Key problem areas are the SF Delta Lake Tahoe.

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Spotlight on suspended sediments/turbidity

• Soil erosion, wastewater and the growth of
  microorganisms raise turbidity, reduce light
  penetration and increase adsorption of solar
  heat.
• Food chains are affected and levels of tolerance
  are exceeded for sensitive aquatic organisms.
• Dissolved oxygen levels are inversely related to
  water temperature levels.
• Suspended sediments make water treatment more
  necessary, more difficult and more expensive.
• Suspended sediments eventually deposit and cover
  spawning habitats and reduce water depths.

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Sediment/turbidity hot spots

• Sierra and North Coast streams
• subject to logging and development
• erosion seriously affects salmonid species (coho,
  chinook, steelhead).
• SF Delta
• municipal wastewater treatment discharge upstream
  is well over 250 mgd
• introduces more than 200,000 of suspended
  sediments, oxygen demanding wastes and nutrients
  into the river system daily.
• Lake Tahoe
• Nutrient loading leading to algal growth,
  sediment from construction sites, road gritting,
  forest harvesting areas and ski slopes, and other
  sources, have raised turbidity.
• Clarity of this world famous lake, as measured by
  a secchi disk, has fallen rapidly (hence the Keep
  Tahoe Blue stickers!)

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Trinity/Klamath Rivers

• Salmon and Steelhead reproduction depends on
  water quality - eggs incubate 40-60 days in clean
  gravel.
• Increased temp., fine sediments, toxic chemicals
  or lower pH, rapid temp. changes, low dissolved
  oxygen all reduce viability of eggs and raise
  mortality of fry.
• Cutting trees mobilizes sediments from rain
  impact, surface disturbance, runoff from
  roads/skids, disturbed stream banks, debris
  blocked streams.
• Removing trees close to streams increases light
  penetration by removing shade, heating water.
• Fertilizers applied to cut areas leaches to
  streams causing algal growth and pesticides
  dissolve into runoff.

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Spotlight on Pathogens

• Natural contaminants (wild animal feces) and
  pollutants (human and domestic animal feces
  especially cows,dogs).
• Principal sources of pathogenic organisms in CA
  water bodies include
• Accidental releases of untreated sewage - during
  storms because of sewer-storm-drain interties,
  every day because of broken sewer lines and
  leaking septic tanks
• Livestock feedlots from runoff and by dumping
  or overflow of manure heaps/ponds to creeks
• Urban runoff especially pet waste.
• Chlorination does not kill all organisms,
  ozonation does better job - many agencies
  switching (e.g. Alameda County).
• Issue for recreational waters too swimming
  lakes, coastal shallows.

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Pathogen Hot Issues

• Main concern in California is City/County of SF
  which does not filter the majority of its water
  (why SF wants to protect its Peninsula watersheds
  from recreation).
• Also some San Diego Co. beaches are frequently
  polluted bacteriologically.
• Could be a problem everywhere if water treatment
  systems are defective (e.g. Milwaukee 1993 -
  treatment system bypassed, 403,000 ill, 100
  reported dead from Cryptosporidium) E. Coli was
  a problem on and off in Antioch in the 1990s.
• Most common potential diseases - amebiasis,
  campylobacteriosis, cryptosporidiosis,
  giardiasis, hepatitis, shigellosis, salmonella,
  viral gastroenteritis.

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Spotlight on Nitrates

• Nutrients are a problem for their eutrophication
  effects but locally can have health effects when
  found in the form of elevated nitrate levels.
• Use of chemical fertilizer on agricultural lands
  and leaching from cattle feedlots accumulates
  heavy concentrations of soluble nitrates in the
  groundwater below.
• Prolonged exposure to levels above 10 mg/l can
  lead to stomach cancers and blood anemia problems
  especially in children (methemaglobanemia).
• Nitrate removal is very expensive and thus the
  problem is best avoided.
• Key hot spot areas are in the San Joaquin
  (Central Valley) and San Gabriel Valleys
  (Southern Cal).