Boyle, John (Anuil Cottage, Bentham Street Ardler-by-Meigle, Perthshire PH12 8SU, GB)
| 1. | A process for degrading a relatively lipophilic hazardous chemical which is susceptible to base hydrolysis, the process comprising contacting the chemical with an effective amount of a water soluble base in an aqueous medium in the presence of an effective amount of a surfactant. |
| 2. | A process according to claim 1, in which the base is soluble to the extent of forming at 200C a saturated aqueous solution which is greater than about 0.lem. |
| 3. | A process according to claim 1 or 2, in which the base is a strong base. |
| 4. | A process according to claim 3, in which the base is an alkali metal hydroxide or ammonium hydroxide. |
| 5. | A process according to claim 4, in which the base is sodium hydroxide. |
| 6. | A process according to any one of the preceding claims, in which the base is used at a concentration of up to about 2% by weight (base: aqueous medium). |
| 7. | A process according to any one of the preceding claims, in which the pH of the aqueous medium during the degradation is above about 10. |
| 8. | A process according to any one of the preceding claims, in which the surfactant is a nonionic surfactant, an anionic surfactant or a blend of nonionic and anionic surfactants. |
| 9. | A process according to claim 8, in which the nonionic surfactant is selected from ethoxylated alkylphenols, ethoxylated aliphatic alcohols, ethoxylated amines, ethoxylated fatty acids and fatty acid esters, ethoxylated alkylolamides, block polymers/copolymers of ethylene oxide and propylene oxide, alkylolamides, ethoxylated/propoxylated alkylphenols or fatty alcohols, ethoxylated vegetable oils and mixtures thereof. |
| 10. | A process according to claim 8 or 9, in which the anionic surfactant is selected from sulphonates, betaines, sulphates, phosphate esters, sulphosuccinates and mixtures thereof. |
| 11. | A process according to any one of the preceding claims, in which the hydrophilelipophile balance (HLB) of the surfactant is above about 8. |
| 12. | A process according to claim 11, in which the HLB of the surfactant is about 12 to 13. |
| 13. | A process according to any one of the preceding claims, in which the hazardous chemical is formulated in an organic carrier and the surfactant has a lipophile portion having affinity for the organic carrier. |
| 14. | A process according to any one of the preceding claims, in which the surfactant is the ethoxylated fatty (aliphatic) alcohol Synperonic 91/6G. |
| 15. | A process according to any one of the preceding claims, in which the surfactant is present at a concentration of up to about 2% by weight. |
| 16. | A process according to any one of the preceding claims, in which the relatively lipophilic hazardous chemical is a synthetic pyrethroid, an avermectin or an organophosphorus compound. |
| 17. | A process according to any one of the preceding claims, in which the base and surfactant are used in amounts sufficient to cause the base hydrolysis reaction to be sufficiently advanced after about twelve hours that the hazardous chemical will then be either absent or present in negligible amounts. |
| 18. | A process according to any one of the preceding claims, when performed in situ on a hazardous pesticidal chemical present in a dipping bath after use of the dipping bath in animal husbandry for dipping the animals. |
| 19. | A kit of parts for use in a process according to any one of the preceding claims, the kit comprising a first container holding as an Acomponent a quantity of the base and a second container holding as a Bcomponent a quantity of the surfactant, together with instructions for adding the A and B components to the hazardous chemical to be degraded. |
| 20. | A kit according to claim 19, in which the base is provided in solid form. |
| 21. | A kit according to claim 19 or 20, in which the surfactant is provided in liquid form. |
| 22. | A process for degrading a synthetic pyrethroid of general formula I wherein: Rl and R2, which may be the same or different, are selected from Cl6alkyl, halo and halosubstituted C,~,alkyl ; R3 and R4 together represent a valence bond (creating a C=C double bond) or may be selected from the same groups as Rl and R2 may be selected from; R5 is selected from hydrogen and cyano; and R6 is selected from in which R7 is selected from hydrogen, halo and cyano, and at a degradation rate of greater than 90% degradation in 12 hours, the pyrethroid being formulated in an organic carrier, the process comprising contacting the pyrethroid with a water soluble base in an aqueous medium in the presence of a surfactant selected from those surfactants having an HLB value above about 8 and a lipophile portion having affinity for the organic carrier in which the pyrethroid is formulated. |
| 23. | A process according to claim 22, in which the base is sodium hydroxide and the surfactant is Synperonic 91/6C. |
| 24. | A kit of parts for use in a process for degrading a synthetic pyrethroid of general formula I wherein: R1 and R2, which may be the same or different, are selected from Cl6alkyl, halo and halosubstituted C16alkyl; R3 and R4 together represent a valence bond (creating a C=C double bond) or may be selected from the same groups as R1 and R2 may be selected from; R5 is selected from hydrogen and cyano; and R6 is selected from in which R7 is selected from hydrogen, halo and cyano, and at a degradation rate of greater than 90% degradation in 12 hours, the pyrethroid being formulated in an organic carrier, the kit comprising a first container holding as an A component a quantity of a watersoluble base and a second container holding as a Bcomponent a quantity of a surfactant, the surfactant being selected from those surfactants having an HLB value above about 8 and a lipophile portion having affinity for the organic carrier in which the pyrethroid is formulated; and the quantities of A and B components being selected to be effective to degrade a predetermined standard quantity of the pyrethroid, together with instructions for adding the A and B components to the pyrethroid to be degraded. |
| 25. | A kit according to claim 24, in which the base is sodium hydroxide and the surfactant is Synperonic 91/6G. |
| 26. | A process according to claim 1, substantially as herein described. |
| 27. | A process according to claim 1, substantially as herein described with reference to the Examples. |
| 28. | A kit of parts for use in a process according to claim 1, substantially as herein described. |
| 29. | A kit of parts for use in a process according to claim 1, substantially as herein described with reference to the Examples. |
Many chemicals are sufficiently hazardous to require some form of degradation before disposal. Such degradation typically involves a chemical reaction which splits the hazardous chemical molecule into relatively harmless smaller molecules.
In the case of hazardous chemicals that are susceptible to base (alkaline) hydrolysis, for example, the degradation can often be conveniently accomplished by addition of a base Such chemicals are characterised by the presence of an electrophilic carbonyl grouping, and include many common pesticides, insecticides, acaricides and agrochemicals.
Base hydrolysis is a potentially useful degradation method for many of the most hazardous pesticides currently in use in animal husbandry, such as synthetic pyrethroids, avermectins and organophosphorus compounds.
In practice, however, this potential has not been fully realised.
Thus, for example, it is known to add slaked lime (calcium hydroxide) into a Diazinon (R) (O,O-diethyl-O- (2-isopropyl-6-methyl-pyrimidin-4-yl) phosphorothioate) dip bath after sheep dipping, to degrade the hazardous pesticide. The lime is added at a rate of about 10 kg per 1000 litres of dip wash (approximately 1% base by weight), mixed thoroughly, covered and allowed to stand for three days. The cover is then removed and the dip wash again thoroughly mixed, re-covered, and left for a further four days (1997/98 NOAH Compendium of Data Sheets for Veterinary Products, pages 125-126). The treated dip wash is then sprayed onto a suitable area of land at a rate of up to 5000 litres per hectare.
In the case of synthetic pyrethroids, Bayer have recommended that Bayticol (R) (flumethrin) should be degraded using 50 kg quicklime (calcium oxide) per 1000 litres of dip wash (approximately 5% base by weight) and left for fourteen days with re-mixing every two to three days. It is recommended that the degraded spent dip wash is then applied to farm land at a maximum rate of 5000 litres/hectare (Leaflet entitled "Safer Dip Disposal" published by Bayer plc, Bury St. Edmunds, UK, May 1996) .
These known degradation methods are time-consuming and troublesome for farmers. Not only do large volumes (e.g.
1000 to 3000 litres) of spent dip wash have to be stored safely for many days, but they have to be regularly re- mixed and inspected. The lime base is poorly water- soluble and tends to sediment out, reducing its effectiveness and leading to handling and disposal difficulties.
Because of these problems, it is still common practice to spray untreated spent dip wash onto any available area of land, on the assumption that natural bacterial degradation of the hazardous chemical will take place.
This is unsatisfactory because of the high toxicity of the hazardous chemical to many organisms.
It is an object of the present invention to provide an improved degradation process which goes at least some way towards overcoming the above disadvantages of known methods.
We have now found that significantly faster degradation speeds can be achieved if a water-soluble base is used in the presence of a surfactant. Without wishing to be bound by theory, it is believed that the surfactant may optimise the contact between the base and the relatively lipophilic hazardous chemical, by causing the hazardous chemical to be dispersed providing a larger surface area of contact between the water and oil phases. The nature
of the emulsion is not believed to be critical; for example, it may be an oil-in-water, water-in-oil, microemulsion or solubilised system.
According to a first aspect of the present invention, therefore, there is provided a process for degrading a relatively lipophilic hazardous chemical which is susceptible to base hydrolysis, the process comprising contacting the chemical with an effective amount of a water-soluble base in an aqueous medium in the presence of an effective amount of a surfactant. The base and surfactant are preferably used in amounts sufficient to cause the base hydrolysis reaction to be completed in a period of less than seven days, preferably less than three days, and more preferably less than two days. It is most preferred that the degradation will be sufficiently advanced after one day, most suitably after twelve hours, that the hazardous chemical will then be either absent or present in negligible amounts.
By "hazardous chemical!! is meant a chemical that cannot legally be disposed of through rivers, watercourses or public drainage or sewerage systems, or cannot be so disposed of without significant risk to aquatic life, at the concentrations in which it is used or at lower concentrations to which it may reasonably be diluted after use.
By relatively lipophilic is meant that the hazardous chemical is poorly soluble or insoluble in water at normal temperatures and is usually formulated in a non- aqueous, e.g. an organic solvent, carrier, which may in turn be provided in another carrier, such as an aqueous suspension.
By "susceptible to base hydrolysis ' is meant that the chemical molecule contains an electrophilic centre at which molecular splitting will take place under nucleophilic hydroxyl attack, resulting in degradation of
the molecule into degradation products which are relatively non-hazardous chemicals.
By "water-soluble base" is preferably meant a base, the saturated aqueous solution of which at 200C is greater than about 0.1M.
The base is preferably a strong base such as an alkali metal (e.g. sodium or potassium) hydroxide or ammonium hydroxide. Other strong bases such as the oxides and hydrides of strongly electropositive metals, such as the alkali metals, may also be used. The concentration of base should preferably be such that the pH remains above about 10 throughout the degradation process, more preferably above about 12 and most preferably about 13.
It is normally sufficient if the degradation process takes place overnight or over a period of a few days; according to the present invention, this can readily be accomplished using concentrations of base up to about 2% by weight (base : aqueous medium), for example, in the range of about 0.1t to about 1% by weight, more suitably about 0.3% to about 0.7% by weight, and most preferably about 0.5% by weight.
The surfactant is suitably selected from known surfactants capable of maintaining insoluble or water- immiscible compounds in dispersed condition in the aqueous medium. The surfactant is present in an amount effective to allow the system to exist as a stable dispersion during the degradation process.
The surfactant may preferably be a nonionic surfactant, an anionic surfactant or a blend of nonionic and anionic surfactants. Conventional cosurfactants may be present, if desired.
Nonionic surfactants include, for example, ethoxylated alkylphenols such as optionally terminally blocked
alkylphenol ethoxylates; ethoxylated aliphatic alcohols; ethoxylated amines; ethoxylated fatty acids and fatty acid esters; ethoxylated alkylolamides; block polymers/copolymers of ethylene oxide and propylene oxide; alkylolamides; ethoxylated/propoxylated alkyl phenols or fatty alcohols; ethoxylated vegetable oils; and mixtures thereof.
Anionic surfactants include, for example, sulphonates such as alkylaryl sulphonates or petroleum sulphonates; betaines; sulphates such as alcohol sulphates or ether sulphates; phosphate esters; suiphosuccinates; and mixtures thereof.
Although nonionic and anionic surfactants are preferred, cat ironic surfactants may also find use in the process of the invention. Cationic surfactants include, for example, quaternised organic ammonium compounds such as tetraalkylammonium salts.
The surfactant should be water-soluble or water-miscible and should not itself represent a significant environmental hazard.
It has been found that the hydrophil e-liphophile balance (HLB) value of the surfactant is related to its effectiveness in the degradation process of this invention. It is preferred that the surfactant should have a relatively high HLB above about 8, more particularly in the general range of about 10 to about 18, for example about 11 to about 15, and most especially about 12 to 13.
A further important criterion in the selection of a suitable surfactant is the affinity of the lipophile (organic) portion of the surfactant molecule for the organic carrier in which the hazardous chemical is formulated. This is essentially governed by the surfactant chemical type.
As surfactants there may be particularly mentioned ethoxylated fatty (aliphatic) alcohols such as Synperonic 91/6G (ICI, UK). Other suitable surfactants include the nonionics Caflon (e.g. Caflon 15QS) and Surfadone (e.g.
Surfadone LP100); the anionics Empigen (e.g. Empigen BB) and Nansa (e.g. Nansa EVM); and the cationics Incroquat (e.g. Incroquat CTC30) and Croquat (e.g. Croquat WKP or Croquat L).
The surfactant may be present at any commercial concentration. At low inclusion rates, the more concentrated the surfactant, the more emulsification of the lipophilic hazardous chemical can take place. On the other hand, an excess of surfactant is wasteful and undesirable from an environmental and cost point of view.
It is normally sufficient if the surfactant is present at a concentration of up to about 2% by weight, for example in the range of about 0.1% to about 1% by weight, more suitably about 0.3% to about 0.7% by weight, and most preferably about 0.3% to about 0.5 by weight.
The degradation process is suitably performed at ambient temperatures, e.g. in the range about 5"C to about 30"C.
While low temperatures should be avoided if possible, the process of the present invention is sufficiently broadly applicable that it will still function effectively at the lower end of the above range. The invention is thus applicable even in midwinter in upland areas of temperate climate zones, where day temperatures may only be a few degrees above freezing.
The process of the present invention is active in degrading synthetic pyrethroids, avermectins and organophosphorus compounds, for example.
The pyrethroids may suitably be represented by the general formula: wherein: R1 and R2, which may be the same or different, are selected from Cl6-alkyl (e.g. methyl, ethyl, propyl, butyl), halo (e.g. fluoro, chloro, bromo, iodo) and halo- substituted C1 6- alkyl; R3 and R4 together represent a valence bond (creating a C--C double bond) or may be selected from the same groups as Rl and R2 may be selected from; R5 is selected from hydrogen and cyano; and R6 is selected from in which R7 is selected from hydrogen, halo and cyano, and and all isomers, derivatives, analogues and mixtures thereof.
There may particularly be mentioned pyrethroids of formula I in which R3 and R4 together represent a valance bond, R6 is
and Rl, R2, RsR RsR and R7 are as follows; R1 .R2 R5R2 R5R2 RsR7 RsR7 Cl Cl H H permethrin CH3 CH3 H H phenothrin Br Br CN H deltamethrfndeltamethrin deltamethrfndeltamethrin Cl Cl ON H cypermethrin Cl CF3 CN H cyhalothrin C1 esl CN F flumethrin Cl Cl CN F cyfluthrin CH3 CH3 CN H cyphenothrin The pyrethroids which include a strongly electron- withdrawing group at RsRs RsRs (e.g. CN)ON) CN)ON) will generally be expected to degrade fast under the process of the present invention.
As avermectins there may be mentioned compounds of general formula: where the broken line indicates a single or a double bond at the 22,23-positions;
RlR1 RlR1 is hydrogen or hydroxy provided that RlR RlR is present only when the broken line indicates a single bond; R2 is Cl6-alkyl (e.g. methyl, ethyl, propyl, butyl), C36-alkenyl (e.g. propenyl, butenyl) or C36-cycloalkyl; R3 is hydroxy, methoxy or =NORM =NORM where R5 is hydrogen or C16 alkyl; R7 is hydrogen, hydroxy or C16-alkyl; and R4 is hydrogen, hydroxy, Cl6-polyalkoxy or in which R6R R6R is hydroxy, amino, mono- or di-CI6-alkylamino or C16-al kanoylamino; and all isomers, derivatives, analogues and mixtures thereof.
There may be particularly mentioned the following avermectins of formula (II) :(II): (II) :(II): abamectin, ivermectin, doramectin, eprinomectin, moxidectin, milbemycin, and all isomers and mixtures thereof.
As organophosphorus compounds there may particularly be mentioned: O-(4-bromo-2,5-dichlorophenyl)-O,O-diethyl0- (4-bromo-2, 5-dichlorophenyl) -0,0-diethyl O-(4-bromo-2,5-dichlorophenyl)-O,O-diethyl0- (4-bromo-2, 5-dichlorophenyl) -0,0-diethyl phosphoro- thioate (bromophos-ethyl); 2-chloro-1- (2, 4-dichlorophenyl) -vinyl2-chloro-1-(2,4-dichlorophenyl)-vinyl 2-chloro-1- (2, 4-dichlorophenyl) -vinyl2-chloro-1-(2,4-dichlorophenyl)-vinyl diethyl phosphate (chlorfenvinphos); <BR> <BR> <BR> <BR> 0,O-diethyl-O-(3,5,6-trichloro-2-pyridyl)phosphoro- thioate (chlorpyrifos); <BR> <BR> <BR> <BR> O,O-diethyl-O- (3-chloro-4-methyl-7-coumarinyl)phosphoro-0,O-diethyl-O-(3-c hloro-4-methyl-7-coumarinyl)phosphoro- O,O-diethyl-O- (3-chloro-4-methyl-7-coumarinyl)phosphoro-0,O-diethyl-O-(3-c hloro-4-methyl-7-coumarinyl)phosphoro- thioate (coumaphos); <BR> <BR> <BR> <BR> O,O-diethyl-O-(2-isopropyl-6-methyl-pyrimidin-4- yl)phosphorothioate (diazonono); <BR> <BR> <BR> <BR> O-2,4-dichlorophenyl-O,O-diethylphosphorothioate O-2,4-dichlorophenyl-O,O-diethylphosphorothioate (dichlofenthion);
2,3-p-dioxanedithiol S,S-bis (O,O,diethylphosphoro- dithioate) (dioxathion); <BR> <BR> <BR> O-ethyl-O- (quinolin-8-yl)-phenylphosphonothioate (oxinothiophos); <BR> <BR> <BR> O,O,O,O-tetraethyl-S,S'-methylenedi(phosphorodithioate) (ethion); 0,0-dimethyl-0-2,4,5-trichlorophenylphosphorothioate (fenchlorphos); <BR> <BR> <BR> O,O-dimethyl-O- (4-dimethylsulfamoylphenyl)phosphoro- thioate (famphur); <BR> <BR> <BR> O,O-dimethyl-O- (4-nitro-m-tolyl)phosphorothioate (fenitrothion); O,O-diethyl-a-cyanobenzylideneamino-oxyphosphonothioate (phoxim); and <BR> <BR> <BR> (E) -O-2-isopropoxycarbonyl-l-methylvinyl-O-methyl- ethylphosphoramidothioate (propetamphos).
It is preferred that the degradation process according to the present invention, when used against pesticides used in animal husbandry, takes place in situ in the dipping bath after the animals have been dipped. For this purpose, the required amount of base is preferably added to the spent dip wash separately from (and preferably after) the required amount of surfactant (as liquid concentrate), and the components then mixed thoroughly (to dissolve the base and disperse the surfactant) , and allowed to stand. The ingredients should be stored in separate containers before use, to avoid base attack on the surfactant itself.
In a second aspect of the present invention, therefore, there is provided a kit of parts for use in the process according to the first aspect of the invention, the kit comprising a first container holding as an A-component a quantity of the base and a second container holding as a B-component a quantity of the surfactant, the nature and quantities of A and B components being selected to be effective to degrade a predetermined standard quantity of a particular hazardous chemical to be degraded, together
with instructions for adding the A and B components to the hazardous chemical to be degraded.
The base is suitably provided in solid form, for example as pellets, granules or small pearls or prills, or as a concentrated solution. The quantity of base is preferably the amount required to treat a convenient amount of hazardous chemical. For example, in the treatment of spent dip wash, one kit may conveniently be of a size to treat 1000 litres of dip wash, and the A- component of the kit may conveniently comprise between about 3 and about 7 kg of base, e.g. about 5 kg.
The surfactant is suitably provided as a concentrate in liquid form. The concentrate suitably contains over about 80% surfactant (organic), with the remainder being solvent to maintain the liquid form. The quantity of surfactant is preferably the amount required to treat the same convenient amount of hazardous chemical. For example, in the treatment of spent dip wash the B- component of a 1000-litre treatment kit may conveniently comprise between about 3 and about 7 litres of surfactant concentrate, e.g. about 5 litres.
In use, the A and B components are added to the hazardous chemical in the aqueous medium and then mixed thoroughly to dissolve the base and to distribute the surfactant.
The aqueous medium is then left for the recommended length of time, as set forth in the instructions accompanying the kit. The recommended length of time will typically be in the range of about 12 to about 48 hours.
The treated aqueous medium, at the end of the recommended length of time, contains the hydrolysis reaction products, the surfactant and the base. It will typically be strongly alkaline, e.g. having a pH in the range of about 10 to about 13. To reduce the pH, it may conveniently be diluted with water and/or mixed with
slurry. It is, however, not necessary for the aqueous medium to be neutralised before disposal; trials have shown that the alkaline medium can be safely disposed of by spraying onto a suitable area of land at a rate of up to 5000 litres of wash per hectare.
The process and kit of the present invention is especially suitable for degrading synthetic pyrethroids at a rate hitherto entirely unknown.
Thus, in one preferred aspect, the invention provides a process for degrading a synthetic pyrethroid of general formula I as defined above at a degradation rate of greater than 90% (preferably substantially 100%) degradation in 12 hours, the process comprising contacting the pyrethroid with a water-soluble base in an aqueous medium in the presence of a surfactant selected from those surfactants having an HLB value above about 8 (more preferably in the range of about 10 to about 18) and a lipophile portion having affinity for the organic carrier in which the pyrethroid is formulated.
In a further preferred aspect, there is provided a kit of parts for use in a process for degrading a synthetic pyrethroid of general formula I as defined above at a degradation rate of greater than 90% (preferably substantially 100%) degradation in 12 hours, the kit comprising a first container holding as an A-component a quantity of a water-soluble base and a second container holding as a B-component a quantity of a surfactant, the surfactant being selected from those surfactants having an HLB value above about 8 (more preferably in the range of about 10 to about 18) and a lipophile portion having affinity for the organic carrier in which the pyrethroid is formulated; and the quantities of A and B components being selected to be effective to degrade a predetermined standard quantity of the pyrethroid, together with instructions for adding the A and B components to the pyrethroid to be degraded.
Many synthetic pyrethroids are conventionally formulated in aromatic hydrocarbon solvents, typically petroleum distillates. It has been found that as A-component sodium hydroxide in an amount leading to about 0.5% by weight (base : aqueous medium) is effective and that as B-component an ethoxylated fatty alcohol such as Synperonic 91/6G in an amount leading to about 0.5% by volume (surfactant concentrate (95%) ; aqueous medium) is effective. Moreover, it is found that the effectiveness is tolerant to extremes of field conditions, for example temperature, poorly calculated concentration of pyrethroid in the dip wash, poorly calculated volume of the dip wash, and fouling of the dip wash by animal faecal matter, urine, fleece lanolin, earth etc.
The following non-limiting examples are included for further illustration of the present invention
Dip washes The data and reported below were obtained following tests on spent ROBUST sheep dip (Robert Young, UK). ROBUST contains as active ingredient the synthetic pyrethroid high-cis cypermethrin (HCC) in an aromatic hydrocarbon solvent and is used to control sheep scab, blowfly strike, lice and ticks.
Spent dip wash remaining after one dipping session typically comprises between about 1000 and about 3000 litres of water and solvent containing HCC at a level of about 100 to about 300 pg/ml.
The following samples were tested: A) A laboratory reconstruction of exceptionally concentrated spent HCC dip wash containing 313.2 Hg/ml HCC; B) A laboratory reconstruction of typical spent HCC dip wash containing 145.5 yg/ml HCC; C1) A sample obtained from an outdoor winter dipping session containing 222.32 pg/ml HCC; C2) A second sample obtained from the same dipping session containing 236.89 Hg/ml HCC; D) A laboratory reconstruction of typical spent HCC dip wash containing 229.89 Hg/ml HCC E) A sample obtained from an outdoor winter dipping session containing about 260 yg/ml HCC.
Test Procedures and Results The following test procedures were employed:
Sample A A laboratory trial, in which NaOH prills, and optionally Synperonic 91/6G concentrate (95%), were added, with thorough mixing at room temperature to dissolve the base and disperse the surfactant, to give concentrations ranging from 0.3% to 1.0% NaOH by weight and 0 to 0.3t Synperonic concentrate by volume. Aliquots of the test medium were withdrawn after 3, 21 and 24 hours and tested for HCC concentration.
The results are shown in Table 1 below: Table 1 I HCC Concentration (ug/ml) Sample Initial 3 hrs 21 hrs 24 hrs l NaOll 1% Synperonic 0.0% 313.2 249.8 85.0 63.0 NaOH 0.5% Synperonic 0.0% 313.2 310.2 218.9 204.2 NaOH 0.5% Synperonic 0.2% 313.2 177.6 ND ND NaOH 0.5% Synperonic 0.3% 313.2 95.6 ND ND NaOH 0.3% Synperonic 0.2% 313.2 269.6 131.1 105.4 ND = not detected (i.e. zero HCC).
Sample B A laboratory trial, in which NaOH prills and Synperonic 91/6G concentrate (95%) were added, with thorough stirring at room temperature to dissolve the base and disperse the surfactant, to give concentrations ranging from 0.4% to 0.5% NaOH by weight and 0.3t to 0.5% Synperonic concentrate by volume. Aliquots of the test medium were withdrawn after 2.5, 4.5 and 6 hours and tested for HCC concentration.
The results are shown in Table 2 below: Table 2 II HCC Concentration (ug/ml) Sample initial 2.5 hours 4.5 hours 6 hours NaOH 0.5% Synperonic 0.5% 145.5 13.9 9.1 ND NaOH 0.4% Synperonic 0.4% 145.5 15.5 12.3 ND NaOH 0.4% Synperonic 0.3% 145.5 37.5 14.7 ND ND = not detected (i.e. zero HCC) Samples C1, C2 and D A three-way comparative trial under field conditions, in which Sample C1 was held in a spent dip bath, Sample C2 was held in a holding tank and Sample D was held in glassware. The trial was performed outdoors in winter at a temperature below 5"C at all times. To each sample, NaOH prills and Synperonic 91/6G concentrate (95%) were added, with thorough stirring, to give an NaOH concentration of 0.5% by weight and a Synperonic concentration of 0.5% Synperonic concentrate by volume.
Aliquots of the test medium were withdrawn every 30 minutes for the first 3.5 hours, then every 60 minutes for the next 2 hours, and finally after 8.5 hours, and tested for HCC concentration.
The results are shown in Table 3 below:
Table 3 il Tine Point (hours) Dip Bath Cl Holding Tank C2 D (ugli) (ug/ml) (ug/ml) 0 222.32 236.89 229.89 0.5 176.80 160.69 186.56 1 125.50 97.59 133.41 1.5 93.12 63.12 105.83 2 64.85 41.64 75.98 2.5 49.52 28.87 60.07 3 32.25 18.71 48.80 3.5 24.94 13.53 41.32 4.5 11.63 6.63 23.34 5.5 8.65 5.38 19.74 8.5 0.00 0.00 6.57 pH Initial 12.74 12.67 12.71 Sample E A trial under field conditions (outdoors in winter) using a standard dip bath, in which bath temperature and pH were monitored in addition to HCC concentration.
The pH and temperature of the spent dip wash in the bath were first measured.
Then NaOH prills and Synperonic 91/6G concentrate (95%) were added to the bath, with thorough stirring, to give an NaOH concentration of 0.5t by weight and a Synperonic concentration of 0.5E Synperonic concentrate by volume.
Aliquots of the test medium were withdrawn after 3.5, 4.5
and 24 hours and tested for pH, temperature and HCC concentration.
The results are shown in Table 4 below: Table 4 1 pH H Temp(OC) Active (ugirni) l 11 Pre Treatmcnt 8.60 6.8 l 11 Initial 13.0 8.7 261.2 I 3.5 Hours 13.28 6.0 40.36 4 5 Hours 13.2 0 24 Hours 13.2 Temperature Dependency A sample of spent ROBUST dip wash (HCC) was obtained from a dipping session conducted under field conditions (outdoors in winter). The sample was split to allow the various trials to be conducted. To each sample Synperonic 91/6G concentrate (95%) was added, with thorough stirring, to give a Synperonic concentration of 0.5% Synperonic concentrate by volume, together with various amounts of NaOH prills to give NaOH concentrations ranging from 0.1% to 0.5% by weight.
The samples were stored either at 2"C or 200C.
Aliquots of the test medium of each sample were withdrawn at the times shown below, and tested for HCC concentration.
The results are shown in Table 5 below, in which the HCC concentrations are expressed as a percentage of the initial concentration (to = 100.0).
Table 5 Degradation at 2°C (Synperonic 91/G at 0.5% level) % Degradation Against initial Initial 1 hr'Ir hr'Ir 2 hrs 4 hrs 6 hrs 8 hrs 24 hrs NaOH0.1% 100.0 93.8 NaOH 0.2% 100.0 91 1 NaOH 0.3% 100.0 67.4 NaOH 0 4%NaOH0A% NaOH 0 4%NaOH0A% 100.0 71.6 58.1 41.1 27.7 20 NaOH 0.5% 100.0 26.7 14.7 6.3 1.7 Degradation at 20°C (Synperonic 91/G at 0.5% level) % Degradation Against Initial Initial I hour 2 hours 3 hours NaOH 04%or% 04%or% 100.0 75 475A 75 475A 61.7 7 | 7 | 47.4 NaOH 0.5% 100.0 16.0 3.7 | | 0.0 Toxicity Studies HCC is highly toxic to aquatic invertebrates. Daphnia magna is commonly used to assess the toxicity of insecticides to this group of organisms and has been used to determine the toxicity of the treated wash. The results are given below: 48 hour LC50 (mg/litre) NOEC (mg/litre) untreated dipwash 1.7 0.5 treated dipwash 1000 630 treated control dipwash 1000 630
LCSo = concentration producing 50% mortality NOEC = concentration having no observable effect treated control dipwash = dipwash initially made up without any HCC Thus, the treated dip wash is approximately 600 times less toxic to Daphnia than the untreated wash and it has the same toxicity as a control dip wash which was originally made up without any HCC and was treated in the same way as real dip wash. Any residual toxicity to Daphnia was probably due to the high pH of the medium.
Surfactant and Clean/Foul Studies Comparative studies have been undertaken on a range of surfactants in place of Synperonic 91/6G, on an HCC degradation system using 0.5t by weight NaOH as well as various control systems (no NaOH). In some cases, the effectiveness of the system against fouled dip washes (i.e. containing faecal and other matter which can absorb both HCC and surfactant and so interfere with the degradation reaction) was also tested. The dip wash was clean unless otherwise stated. The results are shown in Table 6 below: Table 6 % HCC remaining Surfactant* after 24 hours Nonionic Surfactants Caflon 150S (ambient temperature) 0.3% surfactant concentrate with 0.7% NaOH O 0.7h surfactant concentrate with 0.3% NaOH O 0.9% surfactant concentrate with 0.1% NaOH 0
Table 6 (Contd) HCC remaining Surfactant* after 24 hours 0.5% surfactant concentrate with 0.2% NaOH (foul) 11.7 0.5% surfactant concentrate with 0.3% NaOH (foul) 8.8 Caflon 150S (50C) 0.8% surfactant concentrate with 0.2% NaOH 8.8 0.8% surfactant concentrate with 0.2% NaOH (foul) 30.2 0.3% surfactant concentrate with 0.3% NaOH (foul) 21.8 0.3% surfactant concentrate with 0.2% NaOH (foul) 62.3 0.5% surfactant concentrate with 0.3E NaOH (foul) 23.3 Surfadone LP100 (ambient temperature) 0.2% surfactant concentrate with 0.3% NaOH 67.5 0.3% surfactant concentrate with 0.3% NaOH 44.0 0.4h surfactant concentrate with 0.4% NaOH 3.1 0.6% surfactant concentrate with 0.4% NaOH 3.2 Surfadone LP100 (50C) 0.2t surfactant concentrate with 0.3% NaOH 95 5 0.3% surfactant concentrate with 0.3% NaOH 87.0 0.4% surfactant concentrate with 0.4t NaOH 22 2
Table 6 (Contd) HCC remaining Surfactant* after 24 hours 0.6% surfactant concentrate with 0.4% NaOH 2.7 Anionic Surfactants Nansa EVM (ambient temperature) 0.6% surfactant concentrate with 0.4% NaOH 10.5 0.7t surfactant concentrate with 0.5t NaOH 8.2 Nansa EVM (50C) 0.6% surfactant concentrate with 0.4% NaOH 61.9 0 7% surfactant concentrate with 0.5% NaOH 62.6 Cationic Surfactants Incroquat CTC 30 (ambient temperature) 0.8% surfactant concentrate with 0.2% NaOH 31.3 0.6% surfactant concentrate with 0.3% NaOH Incroquat CTC 30 (5°C) 0.6% surfactant concentrate with 0.3% NaOH 6 Croquat L (ambient temperature) 0.6% surfactant concentrate with 0.4% NaOH 13.72 Croquet L (50C) 0.6% surfactant concentrate with 0.4% NaOH 34.3 on on another test day, 9.5% was recorded.
* percentage is percentage of volume of concentrate (usually >90%) added.
Conclusions As a general rule, surfactants of all the three main types can have utility in the process of the present invention. However, only nonionic surfactants appear to
have the ability to withstand the range of adverse conditions found in field conditions, principally low temperatures and fouling of the dip wash by the animals being dipped, and even with those surfactants the use of low base concentrations should be avoided.
The process and kit of the present invention is of broad applicability. It has been found, particularly, that a wide range of base-labile, relatively lipophilic, hazardous chemicals can be degraded under the wide range of field conditions typically encountered, for example temperature, water pH, water hardness, concentration of hazardous chemical, volume of hazardous chemical dispersion, etc. The invention thus demonstrates significant potential for degrading hazardous chemicals from a variety of sources, for example farm animal dipping baths, emulsifiable concentrates, spray compositions, pouron compositions, soluble concentrates, soluble powers and dispersible granules.
The above broadly describes the invention without limitation. Variations and modifications as will be readily apparent to those of ordinary skill in this art are intended to be included within the scope of this description.