[GreenYes] biosolids http://www.biosolids.state.va.us/concerns.htm

[LWheeler45@no.address]

    Concerns & Risks  
 
    *   _Trace  elements_ 
(http://www.biosolids.state.va.us/concerns.htm#trace)   
    *   _Toxic  chemicals_ 
(http://www.biosolids.state.va.us/concerns.htm#toxic)   
    *   _Pathogens_ (http://www.biosolids.state.va.us/concerns.htm#pathogens) 
   
    *   _Odors_ (http://www.biosolids.state.va.us/concerns.htm#odors)    
    *   _Storm water  run-off_ 
(http://www.biosolids.state.va.us/concerns.htm#storm)   
    *   _Groundwater  contamination_ 
(http://www.biosolids.state.va.us/concerns.htm#groundwater)   
    *   _Truck  traffic_ 
(http://www.biosolids.state.va.us/concerns.htm#truck)  


Despite over 30  years of research which shows that, when conducted according 
to  regulations, the land application of biosolids is safe, concerns remain  
over soil and groundwater contamination from trace elements, toxic  chemicals 
and potentially harmful disease causing organisms (pathogens).  In response to 
these concerns, _EPA_ (http://www.epa.gov/)   conducted a comprehensive risk 
assessment that evaluated the health risk  to the general population as well 
as to a highly exposed individual, such  as a person who would have direct 
contact with biosolids land application  sites for a lifetime. To date, there have 
been no documented negative  human cases where a biosolids program met all 
the federal and state  requirements.  
Finally, odors  associated with the land application of biosolids are 
considered more of a  nuisance than a health problem. Odors are oftentimes the most  
objectionable aspect of biosolids use on neighboring farms. 
_Trace  elements_ (http://www.biosolids.state.va.us/trace.htm)  (heavy 
metals) 
Historically,  industries disposed of their liquid wastes to the sanitary 
sewer system,  Consequently, highly industrialized cities and places with certain 
 industrial activities such as metal plating factories, produces sewage  
sludges with high metal concentrations. However, since the late 1970s,  
pretreatment requirements have been established and implemented to require  such 
facilities to reduce or remove the metal constituents before they  enter the sanitary 
sewer system. This has resulted in significantly  decreased levels of heavy 
metals in biosolids. Between the national  surveys of biosolids in the late 
1970s and the survey from the late 1980s  (both conducted by _EPA_ 
(http://www.epa.gov/) ), the average  lead level decreased from 969 mg/kg to 134 mg/kg. 
Nickel levels decreased  from 135.1 mg/kg to 42 mg/kg, and cadmium levels from 69 
mg/kg to 7 mg/kg.   
Furthermore, _EPA_ (http://www.epa.gov/)  conducted a comprehensive risk  
assessment for pollutants in biosolids that are land applied. The risk  
assessment evaluated risks to human health as well as ecological risks (to  animals and 
plants) through 14 exposure pathways for land application.  Current 
regulations based on the risk assessment, set forth conservative  pollutant limits and 
other requirements that protect public health and the  environment. 
_top of page_ (http://www.biosolids.state.va.us/concerns.htm#top)    
Toxic chemicals 
Certain toxic  chemicals that do not volatilize or decompose during treatment 
may  concentrate in biosolids. Residues from the chemicals have declined over 
 the past 20 years. Benzene for example was detected in 93% of biosolids  
samples in a survey conducted during the late 1970s, but in only 3% of  samples 
from the late 1980s. Detection of persistent pesticides such as  chlordane, 
dieldrin, heptachlor, and hexachlorobenzene were detected in  16% of the 1970s 
samples, but none of the 1980s samples. These declines  are due to pretreatment, 
chemical bans and the phasing out of  chemicals. 
In developing  current regulations, EPA considered about 200 toxic organic 
compounds.  After conducting extensive risk analyses on the 31 that were the 
most  threatening, the agency concluded that they appeared so rarely, or at such  
low concentrations that they did not need regulations. 
_top of  page_ (http://www.biosolids.state.va.us/concerns.htm#top)  
Pathogens 
A major public  health and environmental concern associated with land 
application of  sewage sludge is the effect of pathogens on humans and animals. 
Municipal  wastewater generally contains four major types of human pathogenic  
(disease-causing) organisms: bacteria, viruses, protozoa and helminthes  
(parasitic worms). The potential for exposure diminishes over time as  environmental 
conditions such as heat, sunlight, desiccation, and other  microorganisms 
destroy pathogens that may be present in biosolids.   
In order to be  approved for land application, biosolids must have been 
treated to reduce  the number of pathogenic organisms. There are two classes of 
pathogen  treatment, referred to as Class A and Class B. Class A pathogen 
treatment  is the most rigorous and this biosolids can be applied to any land  
including lawns, gardens and areas freely accessible to the general  public. There 
are no site restrictions so biosolids that meet Class A  standards are treated 
and handled with the same care as regular  fertilizers and soil conditioners. 
Class B biosolids receive less rigorous  treatment. While safe to land apply, 
there are site restriction pertaining  to harvest of plants, use of the land 
for grazing, and public  access. 
_top of  page_ (http://www.biosolids.state.va.us/concerns.htm#top)  
Odors 
Many of the odors  associated with biosolids are reduced during the treatment 
process. As  organic materials breakdown, odors are released. Thus is the 
case with  biosolids, which like other manures, will release odors. The method of 
 biosolids treatment also affects odors. Lime stabilized biosolids will  have 
a slightly sweet ammonia odor. Digested biosolids will have a more  organic 
aroma. In most cases, odors dissipate after several days, similar  to animal 
manures.  
_top of  page_ (http://www.biosolids.state.va.us/concerns.htm#top)  
Storm water runoff 
Biosolids absorbed  to soil particles may runoff from land applied fields 
into nearby streams  and surface waters. In order to prevent water pollution, 
site restrictions  are required. These include maintaining buffers along 
waterways and  surface waters and restricting slopes where biosolids can be applied to 
 less than 15%. [Diagram of buffers] 
_top of  page_ (http://www.biosolids.state.va.us/concerns.htm#top)  
Groundwater  contamination 
The Biosolids Use  regulations required at least 18 inches of soil depth to 
bedrock or  groundwater. In this way, the soil acts as a protective layer to 
filter  nutrients from entering to groundwater. Furthermore, biosolids 
application  rates are limited to the plant available nitrogen, which can be used by  
the crop. In this way, there are no excess nitrates to leach into the  
groundwater.  
Bacteria and  pathogens in biosolids tend to adhere to the biosolids amended 
soils  because of the organic nature of biosolids. This clinging mechanisms  
prevents potentially disease causing organisms from entering the  groundwater 
while keeping them near the surface where sunlight,  temperature, dryness and 
naturally occurring organisms destroy them.   
_top of  page_ (http://www.biosolids.state.va.us/concerns.htm#top)  
Truck traffic 
Biosolids are  delivered to the site in tractor-trailers for cake biosolids 
or tanker  trucks for liquid biosolids. Each tractor-trailer contains 
approximately  20 wet tons of biosolids (15 % - 35 % solids). Application rates 
generally  equate to about one tractor trailer truckload per acre. Therefore a  
fifty-acre field could receive about 50 truckloads of biosolids resulting  in heavy 
truck traffic during the spreading operation. Truckers are  required to abide 
by Virginia Department of Transportation requirements.  Contractors designate 
haul routes which avoid residential roads whenever  possible. Also, land 
application operations usually occur during working  hours when most people are at 
work and school to minimize inconvenience  caused by the trucks.  
_top of  page_ (http://www.biosolids.state.va.us/concerns.htm#top)   
(http://www.biosolids.state.va.us/concerns.htm#top)  
_Contact us!_ (mailto:dlopasic@no.address)   








--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups "GreenYes" group.
To post to this group, send email to GreenYes@no.address
To unsubscribe from this group, send email to GreenYes-unsubscribe@no.address
For more options, visit this group at http://groups.google.com/group/GreenYes
-~----------~----~----~----~------~----~------~--~---