EK
What is Biofilm?
Biofilm (a bacterial film) is a mixture of different micro-organisms that are held together and protected by glue-like materials (carbohydrates)[F1]. The glue-like material that micro-organisms secrete allow them to attach themselves to surfaces. Listeria, Pseudomonas, Bacillus, Escherichia coli and Salmonella are some common micro-organisms found in biofilms.–Over time, bacteria on food contact surfaces (some carrying disease) can form into biofilm. In food production areas, biofilm is a sign that the area is unsanitary and needs to be properly cleaned. Unsanitary food surfaces can contaminate food products and reduce their shelf life. Biofilm in the food industry has high food residue and mineral content. It grows over time and becomes strongly attached to food contact surfaces. The greatest concern is that biofilm may contribute to the production of contaminated products from cross contamination.
Removing Biofilm
If biofilm is a concern in your facility, it’s important to clean and sanitize frequently and thoroughly. It’s also important to work with your chemical supplier to find the right products to remove and eliminate biofilms.—Removal of biofilm is achieved by a combination of four factors: 1) formulations and concentrations of cleaning and sanitizing agents 2) exposure time 3) temperature 4) mechanical activity[F2] The combination of these four things can dissolve biofilm and the organic material it sticks to. [F3]Extensive scrubbing with proper chemicals is important, because any biofilm residue can promote more biofilm growth. Talk to your chemical supplier to find the right system for your facility. The location, age, and history of biofilm formation within your facility will shape the guidelines to these four factors. Biofilm micro-organisms can have a high resistance to chemicals and you need to find the right combination to ensure effectiveness.
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Estimating downwind concentrations of viable airborne microorganisms in dynamic atmospheric conditions.
B Lighthart and
A J Mohr
1. Environmental Research Laboratory, U.S. Environmental Protection Agency, Corvallis, Oregon 97333.
ABSTRACT
A Gaussian plume model has been modified to include an airborne microbial survival term that is a best-fit function of laboratory experimental data of weather variables. The model has been included in an algorithm using microbial source strength and local hourly mean weather data to drive the model through a summer- and winter-day cycle. For illustrative purposes, a composite airborne “virus” (developed using actual characteristics from two viruses) was used to show how wind speed could have a major modulating effect on near-source viable concentrations. For example, at high wind speeds such as those occurring during the day, or with short travel times, near-source locations experience high viable concentrations because the microorganisms have not had time to become inactivated. As the travel time increases, because of slow wind speed or longer distances, die-off modulation by sunshine, relative humidity, temperature, etc., potentially becomes increasingly predominant.
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Allergic reaction to antibiotic residues in foods? You may have to watch what your fruits and veggies eat
Source-American College of Allergy, Asthma and Immunology (ACAAI)
People with food allergies always have to watch what they eat. Now, they may have to watch what their fruits and vegetables eat, as it seems it’s possible to have an allergic reaction to antibiotic residues in food.–An article published in the September issue of Annals of Allergy, Asthma and Immunology, the scientific publication of the American College of Allergy, Asthma and Immunology (ACAAI), examines the case of a 10 year-old girl who had an anaphylactic (severely allergic) reaction after eating blueberry pie. Although she had a medical history of asthma and seasonal allergies, and known anaphylaxis to penicillin and cow’s milk, she wasn’t known to be allergic to any of the ingredients in the pie.–After weeks of testing on both the young girl and a sample of the pie, the article authors decided that what had caused the reaction was a streptomycin-contaminated blueberry. Streptomycin, in addition to being a drug used to fight disease, is also used as a pesticide in fruit, to combat the growth of bacteria, fungi, and algae.–“As far as we know, this is the first report that links an allergic reaction to fruits treated with antibiotic pesticides,” said allergist Anne Des Roches, MD,FRCP, lead study author. “Certain European countries ban the use of antibiotics for growing foods, but the United States and Canada still allow them for agricultural purposes.”-[F4]The authors note that new regulations from the Food and Drug Administration may help to reduce antibiotic contaminants in food, which will help reduce antibiotic resistance and may also help reduce this type of event.–“This is a very rare allergic reaction,” said allergist James Sublett, MD, ACAAI president-elect. “Nevertheless, it’s something allergists need to be aware of and that emergency room personnel may need to know about in order to help determine where anaphylactic reactions may arise. Anyone who is at risk for a life-threatening allergic reaction should always carry epinephrine[F5]. They also need to know how to use their epinephrine [F6]in an emergency situation.”–Story Source–The above story is based on materials provided by American College of Allergy, Asthma and Immunology (ACAAI). Note: Materials may be edited for content and length
Recipe—if one has allergies sustaining a good dose of vitamin C will block or minimize the histamine release which may trigger a allergic response and sustain using nettle leaf or root as tea—utilizing as well pine bark –quercitrin and zinc ( which all would support the bronchrial area and strengthen and support the lungs as well from infection ) also things like feverfew—methionine – and Korean ginseng ( minimize use with young people since it can be overpowering) and aloe vera
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Atmospheric Nanoparticles Impact Health
Nanoparticles are atmospheric materials so small that they can’t be seen with the naked eye[F7], but they can very visibly affect both weather patterns and human health all over the world and not in a good way, according to a study by a team of researchers at Texas A&M University.-Researchers Lin Wang, Renyi Zhang, Alexei Khalizov, Jun Zheng, Wen Xu, Yan Ma and Vinita Lal in the Departments of Atmospheric Sciences and Chemistry say that nanoparticles appear to be growing in many parts of the world[F8], but how they do so remains a mystery.—Their work is published in the current issue of “Nature Geoscience” and was funded by the National Science Foundation and The Welch Foundation. –The team looked at how nanoparticles are formed and their relationship with certain organic vapors responsible for additional growth.–This is one of the most poorly understood of all atmospheric processes, Zhang says. But we found that certain types of organics tend to grow very rapidly. When this happens, they scatter light back into space, and that definitely has a cooling effect sort of a reverse greenhouse effect.’ It can alter Earth’s weather patterns and it also tends to have a negative effect on human health.–Persons with breathing problems, such as those who suffer from asthma, emphysema or other lung ailments, can be at risk, he notes.–Zhang says the team used new methods of measuring nanoparticles and formed new models to determine their impact on atmospheric conditions. These changes on our weather systems appear to be the most dramatic consequences of these nanoparticles, he adds.– Once these form, they can change cloud formations, which in turn can affect weather all over the world, so this can become a global problem to deal with. We’re trying to get a better understanding of these particles work and grow. They can form near areas that have petrochemical plants, such as Houston, which also has high amounts of aerosols from traffic emissions and other numerous factories.[F9] But were still trying to learn how they form and interact with the atmosphere.–Many types of trees and plants also contribute to the formation of nanoparticles[F10], which are natural processes, Zhang says, and certain forms of organic materials can also speed up the development of the particles. But all of these ultimately affect the atmosphere, and very often, cloud formation, where the aerosols scatter light and radiation back into space and provide the seeds of cloud droplets and development.– These nanoparticles are very small about one million times smaller than a typical raindrop, Zhang says. But what they do can have a huge effect on our weather.–Contact: Renyi Zhang at (979) 845-7656� or Keith Randall, News & Information Services, at (979) 845-4644
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Chelant extraction of heavy metals from contaminated soils.
Peters RW.
Author information
Abstract
The current state of the art regarding the use of chelating agents to extract heavy metal contaminants has been addressed. Results are presented for treatability studies conducted as worst-case and representative soils from Aberdeen Proving Ground’s J-Field for extraction of copper (Cu), lead (Pb), and zinc (Zn). The particle size distribution characteristics of the soils determined from hydrometer tests are approximately 60% sand, 30% silt, and 10% clay. Sequential extractions were performed on the ‘as-received’ soils (worst case and representative) to determine the speciation of the metal forms. The technique speciates the heavy metal distribution into an easily extractable (exchangeable) form, carbonates, reducible oxides, organically-bound, and residual forms. The results indicated that most of the metals are in forms that are amenable to soil washing (i.e. exchangeable+carbonate+reducible oxides). The metals Cu, Pb, Zn, and Cr have greater than 70% of their distribution in forms amenable to soil washing techniques, while Cd, Mn, and Fe are somewhat less amenable to soil washing using chelant extraction. However, the concentrations of Cd and Mn are low in the contaminated soil. From the batch chelant extraction studies, ethylenediaminetetraacetic acid (EDTA), citric acid, and nitrilotriacetic acid (NTA) were all effective in removing copper, lead, and zinc from the J-Field soils. Due to NTA being a Class II carcinogen, it is not recommended for use in remediating contaminated soils. EDTA and citric acid appear to offer the greatest potential as chelating agents to use in soil washing the Aberdeen Proving Ground soils. The other chelating agents studied (gluconate, oxalate, Citranox, ammonium acetate, and phosphoric acid, along with pH-adjusted water) were generally ineffective in mobilizing the heavy metals from the soils. The chelant solution removes the heavy metals (Cd, Cu, Pb, Zn, Fe, Cr, As, and Hg) simultaneously. Using a multiple-stage batch extraction, the soil was successfully treated passing both the Toxicity Characteristics Leaching Procedure (TCLP) and EPA Total Extractable Metal Limit. The final residual Pb concentration was about 300 mg/kg, with a corresponding TCLP of 1.5 mg/l. Removal of the exchangeable and carbonate fractions for Cu and Zn was achieved during the first extraction stage, whereas it required two extraction stages for the same fractions for Pb. Removal of Pb, Cu, and Zn present as exchangeable, carbonates, and reducible oxides occurred between the fourth- and fifth-stage extractions. The overall removal of copper, lead, and zinc from the multiple-stage washing were 98.9%, 98.9%, and 97.2%, respectively. The concentration and operating conditions for the soil washing extractions were not necessarily optimized. If the conditions had been optimized and using a more representative Pb concentration (approximately 12000 mg/kg), it is likely that the TCLP and residual heavy metal soil concentrations could be achieved within two to three extractions. The results indicate that the J-Field contaminated soils can be successfully treated using a soil washing technique.
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A Citizen’s Guide to Soil Washing
What is soil washing?
Soil washing is a technology that uses liquids (usually water, sometimes combined with chemical additives) and a mechanical process to scrub soils. This scrubbing removes hazardous contaminants and concentrates them into a smaller volume. Hazardous contaminants tend to bind, chemically or physically, to silt and clay. Silt and clay, in turn, bind to sand and gravel particles. The soil washing process separates the contaminated fine soil (silt and clay) from the coarse soil (sand and gravel). When completed, the smaller volume of soil, which contains the majority of the fine silt and clay particles, can be further treated by other methods (such as incineration or bioremediation) or disposed of according to state and federal regulations. The clean, larger volume of soil is not toxic and can be used as backfill.
A Quick Look at Soil Washing
Separates fine-grained particles (silt and clay) from coarse-grained particles (sand and gravel).
Significantly reduces the volume of contaminated soil.
Is a relatively low-cost alternative for separating waste and minimizing volume required for subsequent treatment.
Is a transportable technology that can be brought to the site.
How does soil washing work?
A simplified drawing of the soil washing process is illustrated in Figure 1. The equipment is transportable so that the process can be conducted at the site. The first step of the process is to dig up the contaminated soil and move it to a staging area where it is prepared for treatment. The soil is then sifted to remove debris and large objects, such as rocks. The remaining material enters a soil scrubbing unit, in which the soil is mixed with a washing solution and agitated. The washing solution may be simply water or may contain additives, like detergent, which remove the contaminants from the soil. This process is very similar to washing laundry. The washwater is drained out of the soil scrubbing unit and the soil is rinsed with clean water. The larger scale soil washing equipment presently in use can process over 100 cubic yards of soil per day. The heavier sand and gravel particles in the processed soil settle out and are tested for contaminants. If clean, this material can be used on the site or taken elsewhere for backfill. If traces of contaminants are still present, the material may be run through the soil washer again or collected for alternate treatment or off-site disposal. Off-site disposal may be regulated by the Resource Conservation Recovery Act (RCRA) or the Toxic Substance Control Act (TSCA).
Figure 1
The Soil Washing Process
The contaminated silt and clay in the washwater settle out and are then separated from the washwater. The washwater, which now also contains contaminants, is treated by wastewater treatment processes so it can be recycled for further use. As mentioned earlier, the washwater may contain additives, some of which may interfere with the wastewater treatment process. If this is the case, the additives must be removed or neutralized by “pretreatment” methods before the washwater goes to wastewater treatment. Once separated from the washwater, the silt and clay are tested for contaminants. If all the contaminants were transferred to the washwater and the silt and clay are clean, they can be used at the site or taken elsewhere for use as backfill. If still contaminated, the material may be run through the soil washing process again, or collected for alternate treatment or off-site disposal in a permitted RCRA or TSCA landfill.
Not All Soil Is Created Equal
Soil is comprised of fine-grained (silt and clay) and coarse-grained (sand and gravel) particles, organic material (decayed plant and animal matter), water, and air. Contaminants tend to readily bind, chemically or physically, to silt, clay, and organic material. Silt, clay, and organic material, in turn, bind physically to sand and gravel. When the soil contains a large amount of clay and organic material, the contaminants attach more easily to the soil and, therefore, are more difficult to remove than when a small amount of clay and organic material is present.
Why consider soil washing?
Soil washing can be used as a technology by itself, but is often used in combination with other treatment technologies. Perhaps the principal use of soil washing is as a volume reduction technique in which the contaminants are concentrated in a relatively small mass of material. The larger the percentage of coarse sand and gravel in the material to be processed (which can be cleaned and perhaps returned to the site), the more cost-effective the soil washing application will be.
Ideally, the soil washing process would lead to a volume reduction of about 90% (which means only 10% of the original volume would require further treatment). Wastes with a high percentage of fine silt and clay will require a larger quantity of material to go on to subsequent, more expensive treatment. These soils may not be good candidates for soil washing.
Soil washing is used to treat a wide range of contaminants, such as metals, gasoline, fuel oils, and pesticides. There are several advantages to using this technology. Soil washing:
· Provides a closed system that remains unaffected by external conditions. This system permits control of the conditions (such as the pH level and temperature) under which the soil particles are treated.
· Allows hazardous wastes to be excavated and treated on-site.
· Has the potential to remove a wide variety of chemical contaminants from soils.
· Is cost-effective because it can be employed as a pre-processing step, significantly reducing the quantity of material that would require further treatment by another technology. It also creates a more uniform material for subsequent treatment technologies.
What Is An Innovative Treatment Technology?
Treatment technologies are processes applied to hazardous waste or contaminated materials to permanently alter their condition through chemical, biological, or physical means. Treatment technologies are able to alter, by destroying or changing, contaminated materials so that they are less hazardous or are no longer hazardous. This may be done by reducing the amount of contaminated material, by recovering or removing a component that gives the material its hazardous properties or by immobilizing the waste. Innovative treatment technologies are those that have been tested, selected, or used for treatment of hazardous waste or contaminated materials but still lack well-documented cost and performance data under a variety of operating conditions.
Will soil washing work at every site?
Soil washing works best when the soil does not contain a large amount of silt or clay. In some cases, soil washing is best applied in combination with other treatment technologies, rather than as a technology by itself.
Removal of contaminants can often be improved during the soil washing process by adding chemical additives to the washwater. However, the presence of these additives may cause some difficulty in the treatment of the used wastewater and the disposal of residuals from the washing process. Costs of handling and managing the additives have to be weighed against the amount of improvements in the performance of the soil washing process.
Where has soil washing been used?
At the King of Prussia site in New Jersey, soil washing was used to remove metal contamination such as chromium, copper, mercury, and lead from 19,000 tons of soil and sludge at a former industrial waste reprocessing facility. The soil washing process was able to clean the materials to meet clean-up goals for eleven metals. For example, chromium levels went from 8,000 milligrams chromium per kilogram of soil (mg/kg) to 480 mg/kg. Table 1 on page 4 lists some of the Superfund sites where soil washing has been selected.
Table 1
Examples of Superfund Sites Where Soil Washing Has Been Selected *
Name of Site
Status**
Medium
Contaminants
Myers Property, NJ
In design
Soil, sediment
Metals
Vineland Chemical, NJ
In design
Soil
Metals
GE Wiring Devices, PR
In design
Soil, sludge
Metals
Cabot Carbon/Koppers, FL
In design
Soil
Semi-volatile organic compounds (SVOCs)
polyaromatic hydrocarbons (PAHs)
metals
Whitehouse Waste Oil Pits
Predesign
Soil, sludge
Volatile organic compounds (VOCs)
PCBs
PAHs
metals
Cape Fear Wood Preserving
Design complete
Soil
Moss American, WI
Predesign
Soil
PAHs, metals
Arkwood, AR
In design
Soil, sludge
For a listing of Superfund sites at which innovative treatment technologies have been used or selected for use, contact NCEPI at the address in the box below for a copy of the document entitled Innovative Treatment Technologies: Annual Status Report (7th Ed.), EPA 542-R-95-008. Additional information about the sites listed in the Annual Status Report is available in database format. The database can be downloaded free of charge from EPA’s Cleanup Information bulletin board (CLU-IN). Call CLU-IN at 301-589-8366 (modem). CLU-IN’s help line is 301-589-8368. The database also is available for purchase on diskettes. Contact NCEPI for details
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How to Clean Out Polluted Soil
One of the biggest challenges a gardener can face is growing plants in polluted soil. Many things can pollute soil, including chemicals that remain from past uses of the ground, flooding, and sewer back-up. If you think your soil is polluted, it is important to conduct a soil test. You can buy a do-it-yourself soil test, but if you are worried about serious contamination, it might be best to have a professional evaluation of the soil.
For heavily polluted or contaminated soil, especially with deadly chemicals, it would be best to dig up the area and dispose of the existing soil, and then replace it with new. This can be very costly, but depending on the level of pollution, may be the only choice.
If you discover that the soil is only moderately polluted, there are ways you can remedy the situation on your own.
Step 1 – Do a Soil Test
Finding out what your soil lacks or has an abundance of is the first thing that must happen so you can take appropriate steps. By knowing this, you will know what to add to make the soil healthier.
Step 2 – Add Organic Materials
One way to improve your soils health is to add organic matter, such as compost, manure, leaves, or grass clippings. Use a tiller of spade to work the matter into the top 6 to 4 inches of soil. By adding the organic material, you will encourage micro organisms to move into your soil, and you will attract worms which act as natural aerators in soil.
Step 3 – Add Nutrients
Depending on the results of your soil test, add lime to lower pH levels or sulfur to raise the pH level. Add fertilizer to increase nitrogen, potassium and phosphorus.
Step 4 – Improve Drainage
If your soil has poor drainage, it will be harder for it to shed it’s toxins. The compost will help with drainage, but you can also add gypsum and coarse sand to soil to make it less dense. Pea gravel may also be used. Work the materials into the soil well.
Step 5 – Bring in the Micro Organisms
You can add your own micro organisms to the soil to help speed the process. Many of the thrive in contaminated soils, and will suck up and metabolize the pollutants for you.
Step 6 – Grow Plants that Clean the Soil
There are several plants that can help clean up the soil. Sunflowers will draw toxins out of the soil with their roots, and have been used for years as natural detoxifiers. Another plant that will help the process by the same method is ferns. Ferns and sunflowers both work as natural leeches, and will suck up many of the chemical pollutants left behind in the soil.
Step 7 – Continue to Work the Soil
Keep the soil tilled, watered, and fertilized. Between the improved drainage, the micro organisms, the pollutant eating plants, and your care of the soil, it will soon be healthy and ready to garden.