KATHON® WT

WATER TREATMENT MICROBICIDE

Contents

2

Introduction

1 - Performance

2 - Chemical and physical properties

3 - Stability/compatibility

4 - Antimicrobial properties

5 - Comparative efficacy

6 - Application areas

7 - Toxicology and environmental fate

8 - Current regulatory status

9 - References

3

KATHON® WT*,WTE and WTA micro-bicides are high performance, broadspectrum, antimicrobial agents basedon the proven isothiazolone chemistryof Rohm and Haas Company.

They are effective at very low concen-trations in controlling both the plank-tonic and surface growth of bacteria,fungi and algae and have been produ-ced specifically for water treatmentand paper mill applications.

Rohm and Haas Company have develo-ped an unrivalled package of regula-tory approvals and environmental fate,

KATHON® WT :water treatmentmicrobicide

toxicology, and performance data tosupport the use of KATHON® WT inwater treatment applications.

For some years, Rohm and HaasCompany have manufacturedKATHON® WT at facilities approvedaccording to the internationally reco-gnised Quality Standard ISO 9002(equivalent to BS5750 Part 2). Thisreflects the commitment of Rohm andHaas to supply high quality productsfor its customers.

This technical bulletin provides effi-cacy, toxicology and environmentalfate data to allow the safe and effectiveuse of KATHON® WT.

* Unless otherwise specified "KATHON® WT" is used to denote the KATHON® WT group ofbiocides, which includes KATHON® WT, WTEand WTA.

● KATHON® WT microbicides offer numerous outstanding advantages :

Rapid inhibition of growth and macro-molecular synthesis :KATHON® WT causes immediate inhi-bition of growth on coming in contactwith a microorganism. The growthinhibition rapidly becomes irreversibleand results in cell death. Even beforedeath occurs, the KATHON®-treatedorganism is unable to synthesize degra-dative enzymes or the exopolymerswhich facilitate adhesion and biofilmformation.

Broad spectrum activity :KATHON® WT controls the widevariety of algae, bacteria and fungifound in industrial water systems. Sucha broad spectrum product reduces

inventory and handling costs, lowersoperator training expenses and lessensthe risk of dosing error.

Effective at low concentrations :Effective control of such a wide varietyof microorganisms at levels as low as 1 ppm active ingredient byKATHON® WT, provides an unrivalledand cost-effective treatment.

Effective against biofilm :KATHON® WT readily penetrates the surface of adhering biofilm to give effective control of sessile micro-organisms.

Biodegradable/non-persistent in theenvironment :When diluted below use concentra-tions, KATHON® WT, WTA and WTEare readily biodegradable. Theirdecomposition does not lead to thepresence of chlorinated organics in theenvironment.

Effective over a wide pH range :KATHON® WT microbicide exhibitsexcellent performance over a broadpH range, even in alkaline water systems.

1 - Performance Water soluble :KATHON® WT is easily incorporatedinto formulations.

Compatibility :KATHON® WT is compatible withchlorine, corrosion and scale inhibi-tors and most anionic, cationic andnon-ionic formulations at normal uselevels.

Non-surface active :KATHON® WT is non-foaming.

Infrequent dosing :KATHON® WT remains active for longperiods of time in the water system,resulting in low service costs.

Easily deactivated :Spills of the concentrated active com-ponents of KATHON® WT are readilydeactivated to non-toxic substances bythe addition of a slightly acidic solu-tion of sodium metabisulphite orsodium bisulphite.

Low toxicity :Extensive toxicological testing hasshown KATHON® microbicides to beof low toxicity at recommended uselevels. Continued testing ensures thatpotential risks are well defined.

4

The chemical composition, physical and chemical properties of KATHON® WT,KATHON® WTA and KATHON® WTE microbicides are shown in Table 1.

2 - Chemical and physical properties

5-chloro-2-methyl-4-isothiazolin-3-one 2-methyl-4-isothiazolin-3-one

ClS

N-CH3

O

S

N-CH3

O

CAS Registry N° 26172-55-4 CAS Registry N° 2682-20-4

Table 1 - Composition and properties of KATHON® WT microbicides (these values do not constitute specifications)

KATHON® WT KATHON® WTA KATHON® WTE

■ 5-chloro-2 methyl-4-isothiazolin-3-one■ 2-methyl-4-isothiazolin-3-oneTypical value active ingredients 13.9% 1.5% 1.5%

Inert Ingredients 28.0% 3.0% 3.0%

Water to 100% to 100% to 100%

Typical properties

Appearance Clear to slightly hazy liquid

Colour Amber-gold Pale yellow Pale yellow green

Odour Mild Mild Mild

Specific gravity (20°C) 1.32 1.02 1.02

pH (as supplied) 2-4 3-5 3-5

Viscosity (cps) 15°C25°C35°C

19.016.014.5

19.016.014.5

19.019.019.0

● The active ingredient of KATHON® WT biocides is a mixture of two isothiazolones identified by the IUPAC system of nomenclature as :

5

● KATHON® is stable overthe wide range of conditionsfound in cooling water andpaper mill applications.

Product as supplied :KATHON® WT and WTE microbicidesare stable as supplied for at least a yearat ambient temperatures and for 6 months at 50°C. We recommend,however, that KATHON® WTA is stored at 25°C or below for a maxi-mum period of 6 months. Generally,storage conditions appropriate forindustrial chemicals should beemployed, avoiding exposure toextremes of temperature.

3 - Stability/compatibility

At use levels :The performance of biocides in indus-trial water systems is dependent ontheir stability. Several factors caninfluence the rate of degradationincluding water hardness, pH and temperature. The stability ofKATHON® WT is actually enhanced inhard water conditions. At normal uselevels in water treatment systems,KATHON® WT biocides are biologi-cally and physically compatible with :• anionic, cationic and non-ionic sur-

factants• corrosion and scale inhibitors• chlorine (Table 2)• majority of standard paper mill addi-

tives.

Figure 1 shows the excellent stability of KATHON® WT compared with competitive biocides at different levelsof pH, temperature and total waterhardness. This is dealt with in greaterdetail in the section on stability/compatibility.

In addition to its excellent stability atuse levels, KATHON® WT has theadvantage that, when diluted wellbelow its use level, it is readily biode-gradable.

Table 2 - Stability of 10 ppm active ingredient KATHON® WT in the presence of 1.0 ppm freeresidual chlorine

TIME (hours) FREE CHLORINE (ppm) KATHON® WT (ppm AI)

0 1.0 10.0

2 1.0 10.0

4 1.0 9.7

6 1.0 9.8

69 0.1 9.1

Temperature : 27°C ; pH 7.5.

6

A. 37°C/50 ppm TWH*

% R

emai

nin

g in

72

Hou

rs%

Rem

ain

ing

in 7

2 H

ours

0 0 0 0

20

40

60

80

100B. 37°C/1000 ppm TWH

5 ppm AI KATHON

®

50 ppm AI GLUT

10 ppm AI MBT

20 ppm AI DBNPA

5 ppm AI KATHON

®

50 ppm AI GLUT

10 ppm AI MBT

20 ppm AI DBNPA

0 0 0 0

20

40

60

80

100

5 ppm AI KATHON

®

50 ppm AI GLUT

10 ppm AI MBT

20 ppm AI DBNPA

5 ppm AI KATHON

®

50 ppm AI GLUT

10 ppm AI MBT

20 ppm AI DBNPA

C. 50°C/50 ppm TWH D. 50°C/1000 ppm TWH

* Total Water Hardness

DBNPA = 2.2-dibromo-3-nitrilopropionamideGLUT = glutaraldehydeMBT = methylene (bis) thiocyanate (data not yet available at pH 5.5)

pH 5.5pH 7.5pH 9.5

Fig. 1 : Stability of KATHON® WT vs. competitive biocides at different levels of temperature and water hardness over a pH range 5.5-9.5

7

Phoma herbarum (pigmentivora)

* Aureobasidium pullulans

* Rhizopus stolonifer

Rhodotorula rubra (yeast)

Saccharomyces cerevisiae (yeast)

Trichophyton mentagrophytes (interdigitale)

* Aspergillus foetidus

Table 3 - Minimum inhibitory concentrations of KATHON® WT vs fungi a

● KATHON® WT is an extremely effective,broad spectrum microbicidewhich causes an immediateinhibition of growth on coming in contact with a microorganism.

KATHON® WT rapidly interacts withproteins within the cell, causing aninhibition of respiration and ATP syn-thesis, which results in an inability tosynthesize biopolymers or catabolizesubstrate. Growth inhibition rapidlybecomes irreversible and results in celldeath as essential proteins are progres-sively oxidized. Even before cell deathoccurs, the KATHON®-treated orga-nisms are unable to synthesize eitherbiodegradative enzymes or the exopo-lymers which facilitate microbial adhe-sion and biofilm formation.

Minimum inhibitory concentrations

Tables 3-6 show the minimum inhibi-tory concentrations (MIC) ofKATHON® WT active ingredientagainst microorganisms in test-tubeand microtitre plate assays i.e. thelowest concentration which will inhibitmicrobial growth.

4 - Antimicrobialproperties

This data demonstrates broad spec-trum activity against all types of foulingmicroorganisms e.g. fungi, bacteria,and algae. The methods used to obtainthis data are useful for screening anti-microbial substances under standardi-zed laboratory conditions, in nutrientrich growth media. Therefore theeffective levels of active ingredientderived from these tests do not neces-sarily translate into the most effica-cious use levels for particularapplications.

Antimicrobial properties of a watertreatment biocide

Many water treatment biocides have"gaps" in their activity spectra i.e. theymay be good fungicides but poor algi-cides or bactericides. One biocidewhich can perform the function of twoor three different products, saves bothtime and money and reduces thechances of dosing errors. A broad spec-trum biocide, such as KATHON® WT,which prevents the growth of, or killsorganisms causing surface fouling, atlow concentrations, is essential inindustrial water treatment.

ORGANISM

* Aspergillus niger

* Aspergillus oryzae

Candida albicans (yeast)

Chaetomium globosum

* Cladosporium resinae (Hormoconis resinae)

Gliocladium fimbriatum

Lentinus lepideus

Gloeophyllum trabeum

* Mucor rouxii

* Penicillium funiculosum

* Penicillium variabile (glaucum) USDA

9644

R and HL5-83

11539

12653

QM7638

11274

6205

11651

10196

9642

16878

ATCC N°

2

5

5

6

4

9

5

9

5

5

9

8

ACTIVE INGREDIENT (ppm)

12569 2

9348 5

10404 5

9449 2

2601 2

9533 5

8

* Pseudomonas oleoverans

* Pseudomonas cepacia

Shigella sonnei

* Pseudomonas fluorescens

GRAM-POSITIVE

* Bacillus cereus var. mycoides

* Bacillus subtilis

Brevibacterium ammoniagenes

Cellulomonas sp.

Sarcina lutea

* Staphylococcus aureus

* Staphylococcus epidermidis

Streptomyces albus

Azotobacter vinelandii

* Enterobacter aerogenes

Escherichia coli

* Flavabacterium suaveolens

Nitrobacter agilis

* Proteus vulgaris

* Pseudomonas aeruginosa

Table 4 - Minimum inhibitory concentrations of KATHON® WT vs bacteria a

Microorganisms causing fouling of cooling towers.* Microorganisms associated with slime deposits in paper-making processes.

a : The bacteriostatic and fungistatic tests were performed by serially diluting the biocide in trypticase-soy broth followed by a 1:100 inoculation with 24-hour broth cultures of test bacterium or fungal spore suspension (prepared from 7-14 day culture slants washed with 7 mls of deionized water).Minimum inhibitory concentration levels were determined visually after 2 days incubation at 37°C for bacteria and 7 days incubation at 28-30°C for fungi.

ORGANISM

13525

Gibraltar 165

15442

GRAM-NEGATIVE

8427

14123

958

Achromobacter parvulus

11229

3906

12837

* Alcaligenes faecalis 8750

4335

ATCC N°

2

0.75

5

5

0.1

9

8

5

5

2

2

ACTIVE INGREDIENT (ppm)

8062 5

9292 2

R and HL5 2

R and HB2 2

6871 2

21399 6

9341 5

6538 2

155 2

3004 1

9

● Biofilm.

A considerable difference exists bet-ween the efficacy of a biocide againstfree-living or planktonic microorga-nisms and surface-attached or sessilemicroorganisms. Sessile microorga-nisms build up on process surfaces thatare in continual contact with water, toform biofilms, which may vary fromthe more obvious slimy or filamentouslayers, to discrete deposits barelyvisible to the naked eye.

Biofilms consist of complex popula-tions of sessile microorganisms (inclu-ding bacteria, fungi, protozoa andalgae), inorganic and organic debrisbound together by an extracellularmicrobial adhesive1,2 (Fig. 2). Thepolysaccharide matrix protectsmicroorganisms against rapid environ-mental changes, including the addi-tion of many biocides and other watertreatment chemicals, making themmore difficult to kill than their free-living counter-parts. Some biocidesmay also be deactivated by adsorptionto organic and/or inorganic debriswithin the biofilm itself.

Not only do surface-attached microor-ganisms outnumber planktonic popu-lations by several orders of magnitude,but they are also the direct cause ofmost problems in industrial coolingwater systems, air washers and papermills. These include :

Energy loss due to fouling• increased heat transfer resistance• filter blocking• decreasing fluid flow/increasing

pressure drop in pipes

Microbial-induced corrosion• of unprotected metal surfaces

beneath the biofilm

Decreased manufacturing efficiency• breakaway biofilm interferes in paper

manufacture• increased stoppages for cleaning and

maintenance of equipment

Failure of other water treatment chemicals• biodegradation of additives such as

corrosion inhibitors

Potential health effects• biofilm may harbour pathogenic or

potentially pathogenic organisms e.g.Legionella and Pseudomonas spp.

Table 5 - Minimum inhibitory concentrations of KATHON® WT vs algae b

ORGANISM ACTIVE INGREDIENT (ppm)

CHLOROPHYTA (GREEN ALGAE)

Chlorella oleofaciens 0.12

Chlorella pyrenoidosa 0.03

Scenedesmus quadicauda 1.0

Selenastrum capricornutum 0.25

Ulothrix fimbriata 0.63

Ulothrix acuminata 0.63

Table 6 - Minimum inhibitory concentrations of KATHON® WT vs blue green bacteria b

ORGANISM ACTIVE INGREDIENT (ppm)

Synechococcus leopoliensis

CYANOPHYTA/CYANOBACTERIA

0.50

Anabaena flos-aquae 0.03

Schizothriz calcicola

Nostoc commune 0.12

0.31

Oscillatoria prolifera 0.08

Phormidium luridum 0.12

Scytonema hofmanni 0.16

Calothrix parienta 0.31

Microcystis aeruginosa 0.16

Microorganisms causing fouling of cooling towers.

b : A 96-well microtitre plate assay using two-fold serial dilutions in growth media, was employed todetermine MIC values against algae and blue green bacteria. Microorganisms used as inoculumwere grown up on an algal-cyanobacterial medium under constant agitation and with a 16 hourillumination cycle. MICs were determined visually (using a microtitre plate reader) after 14-21 days incubation at 25°C under constant illumination.

10

● The need for activityagainst biofilm.

An industrial water treatment biocidemust be active against biofilm. In spiteof this, many biocides are still only tes-ted against planktonic microorganisms

5 - Comparative efficacy

● Field and laboratory evaluation.

KATHON® WT has been evaluatedagainst competitive biocides in exten-sive laboratory tests and field trials.Results show that it easily out-performsits nearest competitors (Fig. 3).

Fig. 2 : A scanningelectron micro-

graph of a biofilmwhich has built upon a metal surface

in contact withflowing water.

Chains of bacteria(b), and diatoms(d), can easily be

distinguishedwithin the biofilm.

d

b

(see Cooling Water Microbicide sec-tion). Rohm and Haas have been atthe forefront of research into sessiletesting* and have independently deve-loped and tested two laboratorymethods for monitoring the use of bio-cides to control biofouling in industrialwater distribution systems, namely :• model cooling towers• circulating biofilm loops

KATHON® WT is not only effective inkilling microorganisms in existing bio-films, but will also prevent biofilmregrowth when regularly dosed into aclean system.

KATHON® WT is one of the few micro-bicides extensively tested against bio-film organisms during its development.

A more comprehensive discussion ofbiofouling, the problems it causes andthe efficacy of KATHON® WT againstbiofilms, are given in the CoolingWater and Paper Mill Microbicide sections.

* See External Rohm and Haas Publications listat the end of this bulletin.

It produces excellent control againstsessile aerobic and anaerobic microor-ganisms, in both industrial cooling sys-tems (Fig. 4 and Table 7) and as apaper mill slimicide (Fig. 5). Fieldtrials in an industrial air washer havealso proved its excellence as a microbi-cide (Table 8). It is effective over a wide pH range andis therefore ideal for use in the alka-line conditions that exist in multi-cyclecooling towers and modern paper-making. It is attractive economically becauselow levels and infrequent doses can beused successfully.

11

Fig. 3 : Comparative efficacy of KATHON® WT and alternative water treatment biocides against biofilm in model cooling towers (viable cells persq cm).The approximate cost of alternative biocide treatment have been calculated in comparison with that of 1 ppm AI KATHON® WT andare expressed as cost-equivalents

A. KATHON® WT

% o

f No-

trea

tmen

t Con

trol

0

20

40

60

80

100B. DBNPA a

0.5 ppm AI

1.0 ppm AI

2.25 ppm AI

x 1.6 cost/

eq.

x 4.3 cost/

eq.

C. MBT b

% o

f No-

trea

tmen

t Con

trol

20

40

60

80

100

x 0.4 cost/

eq.

x 1.3 cost/

eq.

a. 2,2-dibromo-3-nitrilopropionamide

b. methylene (bis) thiocyanate

BacteriaAlgaeFungi

12

D. TBTO c / Quat

% o

f No-

trea

tmen

t Con

trol

20

40

60

80

100E. BNPD d,e

x 0.7 cost/

eq.

x 1.4 cost/

eq.

x 3.5 cost/

eq.

x 7 cost/

eq.

x 10.5 cost/

eq.

F. Glutaraldehyde

e. bacteria and fungi c.f.u./cm2 ;algae mg chlorophyll/cm2

d. 2-bromo-2-nitropropane-1,3-diol

c. tributyl tin oxide

20

40

60

80

100

x 3.6 cost/

eq.

x 7.2 cost/

eq.

0

BacteriaAlgaeFungi

13

Fig. 4 : Effect of KATHON® WT on naturally occurring microbial populations in an industrial cooling tower

Table 7 - Effect of KATHON® WT on microbial populations in an industrial cooling tower

Log

Num

ber

of M

icro

orga

nis

ms/

ml

Exposure Time in Hours

4020 50 8001

2

3

4

5

6

2 ppm AI5 ppm AI

AREA

SAMPLEDMICROORGANISM INITIAL COUNT

% REDUCTIONa AFTER :

3 WeeksDose

9 ppm AI

5 WeeksDose

1 ppm AI

5 WeeksDose

0.5 ppm AI

Basin Water BacteriaFungiAlgae

1.30 x 106/ml2.80 x 102/ml3.93 x 102/ml

759496

539388

8691–

Slats BacteriaFungiAlgae

2.79 x 109/cm2

1.64 x 105/cm2

3.44 x 105/cm2

9899.5–

979488

9499.296

DistributionBoxes

BacteriaFungiAlgae

4.58 x 1010/cm2

4.19 x 104/cm2

2.06 x 107/cm2

99.999.4

> 99.99

979392

959399.98

a : % Reduction based on initial count.

14

0

350

00

7.4 x 102

SRB/ml c

Fig. 5 : Comparative efficacy of KATHON® WT and carbamate in a paper mill producing newsprint

Table 8 - Effect of KATHON® WTE on the microbial populations in an industrial air washing system a,b

Log

Num

ber

of B

acte

ria/

ml

JAN

FEB

MAR

APRM

AYJU

NJU

LAUG

SEP

OCTNOV

DEC

3

4

5

6

7

KATHON® WT -1984

Carbamate - 1983

Figure 5 illustrates a case history ofbiocide treatment in a newsprint millwhere biocide addition was at thebroke towers. Using carbamate, bacte-rial counts in the broke pulp were

unacceptably high. After changing to acost-equivalent level of KATHON® WT,bacterial counts in the broke weresignificantly reduced and downtimedue to contamination was minimized.

COMMON SUMP AIR WASHERS

Total Count/ml

Fungi/ml SRB/ml c Total Count/ml

Fungi/ml

After 1st dose3 hours24 hours

2.2 x 105

6.0 x 103

0d

009

1.7 x 105

l.0 x 103

01

After 2nd dose3 hours24 hours

9.0 x 103

1.0 x 103

80

800

1.2 x 104

8.0 x 103

00

After 3rd dose3 hours 7.0 x 103 0 0 1.0 x 103 0

Initial Count(No KATHON® WTE)

7.5 x 105 70 6.3 x 102 1.0 x 106 30

a : System ParametersVolume of water : 945,000 litresRetention time : 2.5 cycles (19 days based on blowdown)pH : 7.6KATHON® WTE level : 1.0 ppm AIDose schedule : Initial dose : 60.5 litres KATHON® WTE charged into

common sump (60 ppm as supplied)Subsequent doses : 7.5 litres KATHON® WTE 1.5% chargedinto common sump based on blowdown

b : Visual EvaluationKATHON® WTE maintained a clean system. No problems of odour or foaming wereencountered during or after the trialc : Most probable number of sulphate reducing bacteria/mld : 0 = none detected

15

Fig. 6 : Scanningelectron micro-

graphs of biofilmdevelopment on a

metal surface

a : Scanning electron micrographs taken of a metal

surface that has been subjected to circulating water

for 1 hour (A), 24 hours (B) and 64 hours (C).This

sequence of micrographs shows the initial forma-

tion of a coating of organic debris and inorganic

particles, followed by the attachment of bacteria,

which eventually become embedded in a thick coa-

ting of extracellular microbial adhesive or “slime.”

b : bacteria

i : inorganic debris

o : organic debris

m : polysaccharide matrix (slime)

A

C

B

16

Table 9

APPLICATIONS MAXIMUM USE LEVEL(ppm active ingredients)

1. Industrial cooling water systems 15.0

2. Industrial air washers with efficientmist-eliminating system

l5.0

3. Paper mill slimicides l5.0

● KATHON® WT is ideallysuited to meet the require-ments of an industrial watertreatment biocide.

● Cooling tower microbicide.

KATHON® WT is a broad spectrumbiocide, active against microorganismsin the biofilm. It is cost-effective andideally suited for use in todays alkaline,multi-cycle towers (Fig. 4). A concen-tration of KATHON® WT as low as 1ppm active ingredient, single-dosedevery 3-7 days (depending on blow-down rate) is often sufficient tocontrol severe microbiological fouling.

● Air washer microbicide.

KATHON® WT is very effective incontrolling microbial growth in indus-trial air washing systems (Table 8).

● Paper mill slimicide.

KATHON® WT is a high performancepaper mill slimicide with a broad spec-trum of activity which can cope withthe rapid changes in microbial florathat occur in different papermakingsystems. It penetrates and killsmicroorganisms in the biofilm and isnot inactivated by the high level of sus-pended organic solids found in papermill water. It also provides cost-effec-tive microbial control (Fig. 5).

6 - Applicationareas

● Maximum use levels.

These maximum use levels relate tothe level of KATHON® WT activeingredients which may be constantlypresent in the applications described.Lower maximum use levels may beappropriate in some instances to satisfylocal environmental discharge/regula-tory requirements. For further infor-mation on maximum use levels, pleaserefer to the Safety Guidelines Bulletins.

KATHON® WT microbicide is notdeactivated by suspended organic mat-ter, and is compatible with other watertreatment additives, including chlo-rine. With the recent change of manycooling towers and paper mills to alka-line operating conditions, it is impor-tant to use a biocide such as

KATHON® WT, which remains stableat higher pH values. KATHON® WT isof low toxicity at use levels, easily deac-tivated and biodegradable. In additionto all these essential properties,KATHON® WT is cost-effective.

17

● Rohm and Haas Company,one of the foremost specialtychemical manufacturers,takes every measure toensure that its products aresafe for both people and theenvironment.

Toxicology

In line with this policy, Rohm and Haasprovide comprehensive toxicologicaldata for KATHON® WT, which showsthat it is of low toxicity at use-levels.

Environmental fate

With the tightening of legislationgoverning the quality of industrialeffluent, a major consideration in thechoice of a biocide for industrial water

treatment is its fate in the environ-ment. This is discussed in more detailin the section on Environmental Fateand some of the original research ispublished in the Journal ofAgricultural and Food Chemistry, 23,1060-1075, 1975. Reprints are availableon request.

● KATHON® WT has minimalenvironmental impactbecause of the following properties :

• high performance product• very low use levels• readily biodegradable/non-persistentin the environment• does not lead to the presence of chlo-rinated organics• does not affect performance of wastewater treatment plants

KATHON® WT has been shown to beenvironmentally acceptable by a varietyof test procedures. The criteria foracceptability is beyond the most strin-gent control parameters introduced byregulatory authorities.

This unique combination of propertiesmakes KATHON® WT a first choice forany water treatment programme.

7 - Toxicology andenvironmentalfate

Fig. 7 : Dissipation of KATHON® WT AI in river water

% o

f eac

h c

ompo

nen

t rem

ain

ing

00

20

30

40

50

60

70

80

90

100

10

1 2 4 7 14 35

0.6 ppm 2-methyl-4-isothiazolin-3-one0.006 ppm 5-chloro-2-methyl-4-isothiazolin-3-one0.06 ppm 5-chloro-2-methyl-4-isothiazolin-3-one

0.6 ppm 5-chloro-2-methyl-4-isothiazolin-3-one

18

8 - Current regulatory status

PRODUCT REGULATORYCLEARANCE

KATHON® WT andWTE ActiveIngredient (AI)

BGA Rec. XXXVI“Paper and paperboard”

KATHON® WT andWTE AI

Decree August 7,1987 N° 395

KATHON® WT

KATHON® WTA

N° 9926 N August,1985

N° 10034N

COUNTRY

Germany

Italy

Netherlands

APPLICATION

As slimicide inmanufacture offood contactpaper

Food contactpaper

Paper mill andcooling waterslimicide

KATHON® WTE Swedish ChemicalsInspectorateN° 3401

Sweden Paper millslimicide

KATHON® WT andWTE AI

EGA SubstanceList N° 49466Class III

Switzerland All

KATHON® WT andWTE a

KATHON® WT a

KATHON® WT andWTE a AI

EPA 707-128707-133

EPA 707-132

FDA 21 CFR176.300

USA Cooling towersand air washers

Paper millslimicide

Paper slimicide

NOTES

As a slimicide at amaximum level of4 ppm AI in driedfibre

At 0.1 ppm AImax. extractablefrom paper

Not for foodcontact

Can be used inmanufacture offood contact paper

Up to max. uselevel of 1.4 lbAI/ton dry wgt.paper

● The list below is intendedto assist you and your customers to comply withprevailing regulatorycontrols. It illustrates the sta-tus of KATHON® WT micro-bicide in those countrieswhere specific approvals arerequired.

Current regulatory status

Other grades of KATHON® microbi-cides based on the same active ingredients as KATHON® WT haveobtain FDA or BGA approvals allowingtheir use as preservatives in latex whichis employed in the production of adhe-sives and paper and board for contactwith dry, aqueous and fatty foods.

For further details of those approvals,please contact your local Rohm andHaas Sales Office.

a : These products have different designations in the USA.It should be borne in mind that these clearances apply to KATHON® microbicides as submitted by Rohm and HaasCompany and that formulations containing other ingredients may need to be resubmitted for approval.

Table 10

19

● General.

1. Characklis, W.G. and Cooksey, K.E.(1983). Biofilms and microbial fou-ling. Adv. Appl. Microbiol., 29, 93-138.

2. Costerton, J.W., Geesey, G.G. andCheng, K. (1978). How bacteriastick. Sci. Am., 238, 86-96.

● External Rohm and Haaspublications.

• Costerton, J.W. and Lashen, E.S.(1984). Influence of biofilm on effi-cacy of biocides on corrosion-causingbacteria. Mater. Perform. 23,13-17.

• Haack, T.K., Lashen, E.S. andGreenley, D.E. (1988). The evalua-tion of biocide efficacy against sessilemicroorganisms. In Developments inIndustrial Microbiology, vol. 29. (J. Indust. Micro., Suppl. N° 3) pp. 247-253.

• Haack, T.K., Shaw, D.A. andGreenley, D. E. (1986).Isothiazolones preserve starch-baseddrilling muds. Oil and Gas J., January6th, 1986.

• Krzeminski, S.F., Brackett, C.K. andFisher, J.D. (1975). Fate of microbici-dal 3-isothiazolone compounds in theenvironment : Modes and rates of dis-sipation. J. Agric. Food Chem., 23, (6),1060-1068.

• Krzeminski, S.F., Brackett, C.K.,Fisher, J.D. and Spinnler, J.F. (1975).Fate of Microbicidal 3-isothiazolonecompounds in the environment :Products of degradation. J. Agric.Food Chem., 23, (6), 1068-1075.

• McCoy, W.F. and Lashen, E.S. (1985).Biocide efficacy against sessilemicroorganisms in laboratory model cooling towers. Proc. U.K.Corrosion '85, Harrogate. 259-269.

• McCoy, W.F. and Lashen, E.S. (1986).Evaluation of industrial biocides inlaboratory model cooling towers.Proc. Ann. Meet Cooling Tower Inst.,Paper N° TP-86-17.

• McCoy, W.F., Ridge, J.E. and Lashen,E.S. (1986). Kinetic analysis of a new delivery system for coolingtowers. Proc. 47th Annual Meeting TheInternational Water Conference,Pittsburg, PA.

• McCoy, W.F., Wireman, J.W. andLashen, E.S., (1986). Efficacy ofmethyl-chloro/methylisothiazolonebiocide against Legionella pneumophilain cooling tower water. J. Indust.Micro., 1, 49-56.

• Ruseska, I., Robbins, J., Costerton,J.W. and Lashen, E.S. (1982). Biocidetesting against corrosion-causing oil-field bacteria helps control plugging.Oil and Gas J., 253-264.

• Tanner, R.S., Haack, T.K., Semet, R.F.and Greenley, D.E. (1985). A mildsteel tubular flow system for biofilmmonitoring. Proc. U.K. Corrosion '85,Harrogate. pp. 259-269.

• Williams, T.M. (1988). Growth andcontrol of biofouling microorganismsin modified laboratory coolingtowers. Proc. 2nd Venezuelan CorrosionConference, Venezuelan CentralUniversity, Caracas, Venezuela.

Acknowledgements

The electron micrograph which formsFigure 2 has been reproduced by kindpermission of the Fouling Forum,Harwell Laboratories, U.K. A.E.A.The photograph on page 16 has beenreproduced by kind permission of NewThames Paper Company, part of UKPaper, U.K.

9 - References

More information on the web about our products and services,and all our worldwide addresses :

www.rhcis.comRohm and Haas Consumer and Industrial Specialties

KATHON® is a trademark of Rohm and Haas Company, or of its subsidiaries or affiliates. The Company's policy is to register its trademarks, where products designated thereby are marketed by the Company, its subsidiaries or affiliates.

These suggestions and data are based on information we believe to be reliable. They are offered in good faith, but without guarantee, as conditions and methods of use of our products are beyond our control. We recommend that the prospective userdetermine the suitability of our materials and suggestions before adopting them on a commercial scale.

Suggestions for use of our products, or the inclusion of descriptive material from patents and the citation of specific patents in this publication, should not be understood as recommending the use of our products in violation of any patent or as permission or license to use any patent of the Rohm and Haas Company.

© 2000 Rohm and Haas Company Printed in France BIO. KATHON WT GEN.PB. E. 12/2000

KEYNOTE

CONSULTING