540/09-87-172
      TRIBUTYLTIN:  POSITION DOCUMENT 1
       Office  of  Pesticide Programs
Office of  Pesticides  and Toxic Substances
   U.S. Environmental Protection Agency
             401 M Street,  S.W.
           Washington, DC  20460
               December 1985

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                       Executive Summary
       This Tributyltin Support Document  presents  the  basis  for
 the initiation of a Special Review of  all  pesticide products
 containing tributyltin (TBT)  active ingredients used  as paint
 additives (antifoulants)  to inhibit the  growth of certain aquatic
 organisms.  The TBT paints  are primarily applied  to boat and ship
 hulls._  These TBT compounds include:   bis-(tributyltin) oxide,
 bis(tributyltin) adipate, bis(tributyltin)  dodecenyl  succinate,
 bis(tributyltin) sulfide, tributyltin  acetate, tributyltin  acrylate,
 tributyltin fluoride,  tributyltin  methacrylate, and tributyltin
 resinate.

       The initiation of the Special Review is based on the  Agency's
 determination that the use  of  the  TBT  compounds in antifoulant
 paints may result in TBT  exposure  to nontarget aquatic organisms
 at  concentrations resulting in acute and chronic  effects.   The
 Agency has determined  that  the risk criteria, as  described  in 40
 CFR 162.11 are met or  exceeded by  use  of these TBT antifoulant
 paints.

      The Agency evaluated  bioassay studies which indicated that
 the TBT  compounds are  highly  toxic,  frequently at the parts per
 trillion (ppt)  level,  to  nontarget marine  and freshwater aquatic
 organisms.   Toxicity tests  have  found  adverse affects to molluscs
 at  levels of  60  and 100 ppt.   The  laboratory toxicity measure
 which the Agency used  to  evaluate  the  acute hazard was the  median
 lethal concentration (LC50) which  kills  50  percent of the test
 organisms after  a designated  time  period.   The Agency also  reviewed
 numerous  aquatic toxicity studies  which  indicate  that the TBT
 compounds  cause  chronic hazards  such as  anatomical abnormalities,
 growth effects,  and is  bioaccumulated.

      Environmental monitoring data measuring TBT concentrations
 in the Great  Lakes  and  U.S. coastal waters  were compared to the
 concentrations  identified as causing adverse effects  in the
 laboratory  toxicity studies.   From this  comparison, the Agency
has determined that the risk criteria, as  described in 40 CFR
162.11 are met or exceeded  by  use  of these  TBT antifoulant  paints.

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                         ACKNOWLEDGEMENTS
       Janet L. Anderson
       Kyle R. Barbehenn
       Michael A. Champ
       Stanley A. Cook
       John D. Doherty
       Robert K. Hitch
       Peter Kuch
       Thomas W. Purcell
       Allan J. Reiter
       Michael Rexrode
       Philip J. Ross
       Myra Smith
       Linda K. Vlier
       Suzanne Wells
Project Team

  Plant Pahtologist,  OPP/BUD
  Biologist, OPP/HED
  Senior Science Advisor,  OPPE
  Assist. Review Manager,  OPP/RD
  Toxicologist,  OPP/HED
  Ecologist, OPP/HED
  Supervisory Economist, OPP/BUD
  Environmental  Scientist, OWRS
  Chemist, OPP/HED
  Fisheries Biologist,  OPP/HED
  Attorney, OGC
  Microbiologist, OPP/BUD
  Senior Review  Manager, OPP/RD
  Environ. Protection Specialist,  OPPE
Additional assistance also provided by:

       Robert J. Huggett
       Virginia Institute of Marine Science
       College of William and Mary
       Gloucester Point, Virginia

       Peter F. Seligman
       Marine Environmental Branch
       U.S. Naval Ocean Systems Center
       San Diego, California

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                      TABLE OF CONTENTS


I.    INTRODUCTION  	   1-1

      A.  General Background and Organization 	   1-1
      B.  Legal Background 	   1-1
      C.  Chemical  Background 	   1-2

II.   ASSESSMENT OF RISK 	  II-l

      A.  Toxicity  of TBT to Nontarget Aquatic
            Organi sms 	  11- 2
      B.  Exposure:  TBT in the Marine and
            Freshwater Environment 	  11-13
      C.  Risk Summary 	  11-20

III.  BENEFITS 	 III-l

      A.  Antifoulant Paint Use Pattern 	 III-l
      B.  Tributyltin Antifoulant Paint Registrations ... III-l
      C.  Usage of  Tributyltin Antifoulant Paints
            and Alternatives 	 III-2
      D.  Benefits  of TBT Usage 	 III-3

IV.   OTHER REGULATORY CONSIDERATIONS 	  IV-1

      A.  Expansion of Special Review 	  IV-1
      B.   Data Call-in Notices 	  IV-2

 V.   BIBLIOGRAPHY  	   V-l
                                11
                                                                     3

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 I.    INTRODUCTION

       A.  General Background and Organization


           The Environmental Protection Agency (EPA)  is initiating
 a Special Review of all pesticide products containing tributyltin
 (TBT) active ingredients used as paint additives (antifoulants)
 to inhibit the growth of certain aquatic organisms.   The TBT
 paints are primarily applied to boat and ship hulls.   These
 TBT compounds include:  bis(tributyltin) oxide,  bis(tributyltin)
 adipate, bis(tributyltin) dodecenyl succinate, bis(tributyltin)
 sulfide, tributyltin acetate, tributyltin acrylate,  tributyltin
 fluoride, tributyltin methacrylate, and tributyltin  resinate.
 This Tributyltin Support Document presents the basis  for
 initiation of the Special Review on these nine active ingredients.

           The EPA has determined that the pesticidal  use of
 these compounds results in TBT exposure to nontarget  aquatic
 organisms at concentrations resulting in acute and  chronic toxicity
 and,  when applied as antifoulant paints, meet or exceed the  risk
 criteria as described in 40 CFR 162.11.  Accordingly, a Special
 Review of products containing these TBT compounds and applied
 as antifoulant paint is appropriate to determine whether additional
 regulatory actions are required.  During the  Special  Review
 process, EPA will carefully examine the risks and benefits of
 using TBT products as antifoulants.  If the information reviewed
 indicates that use of these compounds on other sites  results in
 exposure to nontarget aquatic organisms, the  Special  Review  may
 be extended to include other pesticidal applications  of these
 products and other TBT active ingredients with registered uses
 which result in aquatic acute and/or chronic  effects  or other
 effects  of concern.

           This Support Document contains four parts.   Chapter I is
 this  Introduction.   Chapter II describes the  risk to  nontarget
 aquatic  organisms resulting from the use of TBT  compounds in
 antifoulant paints.   Chapter III describes the usage  and benefits
 of  these TBT compounds.   Chapter IV outlines  other  regulatory
 considerations associated with the  TBT compounds.

       B.   Legal  Background

           1.   The Statute

               A  pesticide product may be sold or distributed in
 the United  States only if it is registered or exempt  from regis-
 tration  under the Federal Insecticide,  Fungicide, and Rodenticide
Act (FIFRA)  as  amended (7 U.S.C.  136 et seq.).   Before a product
can be registered,  it  must be shown that it can  be used without
 "unreasonable adverse  effects on the environment" (FIFRA section
3(c)(5)),  that  is, without causing  "any unreasonable  risk to
                                1-1

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 man or the environment,  taking  into  account  the  economic/
 social,  and environmental  costs  and  benefits of  the  use  of
 the pesticide"  (FIFRA section 2(bb)).   The burden  of proving
 that a pesticide  meets this  standard for  registration is at
 all times, on the proponent  of  initial  or continued  registration.
 If at any  time  the Agency  determines that a  pesticide no longer
 meets this standard  for  registration, then the Administrator
 may cancel the  registration  under  section 6  of FIFRA.

           2.   The Special  Review Process

               The term "Special  Review" is the name  being used
 for the  process previously called  the Rebuttable Presumption
 Against  Registration  (RPAR)  process  40  CFR 162.11.   Modifications
 to the process  are described in  the  final Special  Review regu-
 lations  (50 FR 49003).   These regulations will become effective
 after 60 days of  continuous  congressional session  after  the
 issuance of the regulations, which took place on November 19,
 1985.  These  modifications include new  risk  criteria.  Until
 these regulations are  adopted, the present RPAR  procedures
 will remain in  effect  as set forth in 40  CFR 162.11.

              The Special  Review (RPAR) process  provides a
 mechanism  through which  the  Agency gathers risk  and  benefit
 information about pesticides which appear to pose  risks  of
 adverse  effects to human health  or the  environment which may be
 unreasonable.   Through issuance  of notices and support documents,
 the Agency publicly  sets forth its position  and  invites  pesticide
 registrants,  USDI, USDA, FDA, user groups, environmental groups,
 and other  interested persons to  participate  in the Agency's
 review of  suspect pesticides.

              Risk evidence, submitted  to and/or gathered by the
 Agency,  must  be evaluated  and considered  in  light  of  the benefit
 information.  If  the Agency  determines  that  the  risks appear
 to  outweigh the benefits,  the Agency can  initiate  action
 under FIFRA to  cancel, suspend,  and/or  require modification
 of  the terms  and  conditions  of registration.


      C.   Chemical Background

           1.  Registered Uses and Production

              There are  20 tributyltin  compounds registered as
pesticidal  active  ingredients.   Nine of the  TBT  compounds are
registered  for  use in  antifoulant paints.  Other registered uses
of the TBT's  include but are not limited  to:  use  as  wood preser-
vatives, textile  biocides, disinfectants, use in cooling towers,
paper and pulp mills, and  leather processing facilities.  Current
annual domestic production of TBT pesticides for these uses is
estimated at approximately 730,000 to 860,000 pounds  of  active
                               1-2

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 ingredient for the 20 TBT active ingredients.  Approximately
 a third of the TBT is used in antifoulant paints, one third is
 used in wood preservatives, and the remaining third is used
 in other pesticidal formulations.

           2•  Chemical and Physical Characteristics of TBT's in
               Antifouling Paints

               The tributyltin antifouling paints are chemically
 characterized by a tin (Sn) atom covalently bonded to three butyl
 (C^Hg-) moieties.  A representative TBT active ingredient,
 tri-n-butyltin fluoride, may be chemically described by the
 following structural formulas for the undissociated (neutral)
 pure form of the active ingredient and for the water dissociated
 (positively charged) form:
              H9C4 — Sn — C4H9     H9C4 — Sn
               Elemental or inorganic forms of tin (as  in  mineral
 deposits or tin cans) appear to cause negligible toxicological
 effects in man or wildlife.   However,  in contrast,  the TBTs
 display an increased fat solubility and consequently,  enhanced
 ability to penetrate biological membranes, thereby  posing a
 greater toxicity and environmental risk (Thayer 1984).  When
 tributyltin is used as an active ingredient in antifouling paint
 formulations that are applied for example to boat hulls,  the  free
 TBT  ion is leached or released from the paint, providing  fresh
 toxicant at the wetted paint surface to inhibit growth of fouling
 organisms (e.g., barnacles, tubeworms ) .

               Table 1 identifies the nine tributyltin  active
 ingredients under consideration in the  Special Review  and their
 Chemical Abstract Service (CAS) number.

               In general, the TBT antifouling paints may  be
 classified into two categories according to the way  the tributyltin
 moiety  is incorporated into the paint coating and subsequently
 released.   In  the first group,  the conventional freely associated
 coatings (e.g.,  TBT oxide or fluoride), the biocide  is physically
 incorporated into the paint matrix (which contains  the pigment,
 water-soluble  resins, and inert substances).   Upon  contact with
 the marine environment,  the surface particles of the paint coating
 are dissolved  with physical release of  the toxic TBT by diffusion.
 This category  of TBT antifoulant coatings have traditionally
 posed a  problem  of a high early release rate with subsequently
 shortened  time  period of  protection from attachment  and growth
of fouling  organisms (Fisher e_t a±.   1981).   In the  second
category,  the  copoylmer  paints,  the TBT moiety is chemically


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Table 1.  Tributyltin Active Ingredients as Used in
                 Antifoulant Paints
                                    Chemical Abstract
  Chemical Name                       Service Number

bis(tributyltin) oxide                56-35-9
bis(tributyltin) dodecenyl            12379-54-3
  succinate
bis(tributyltin) sulfide              4804-30-4
tributyltin acetate                   56-36-0
tributyltin acrylate                  13331-52-7
tributyltin fluoride                  1983-10-4
tributyltin resinate                  none assigned
tributyltin methacrylate,              2155-70-6,
  and copolymer                         and 26345-187
bis(tributyltin) adipate              7437-35-6
                        1-4
1

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 bonded to a polymer backbone (e.g., TBT methacrylate copolymer).
 This bond is designed to be hydrolytically unstable under
 slightly alkaline conditions.  Therefore, the biocide is
 released only by chemical hydrolysis of the tributyltin itself.
 This attachment (pendant polymer) accounts for several advantages:
 1) release is governed by hydrolysis of the TBT group rather
 than dissolution of the paint particle, 2) the release rate
 can be better controlled (slowed down) by alteration of the
 polymer's water absorption characteristics, and 3)  the formulation
 is safer for shipyard personnel to handle because the biocide
 is released only when wetted and also the polymeric form poses
 less irritation to skin and nasal passages.  With the exception
 of the initial high release rate during the "conditioning"
 period (approximately the first month after the freshly painted
 hull is placed in the water), these polymeric, film-forming
 resin coatings are characterized by a slow dissolution rate from
 ship hulls and thus the ability to achieve a constant but prolonged,
 low release rate of antifouling toxicant (ibid.).

               In general, toxicity of organotin compounds to
 aquatic organisms is thought to increase with the number of butyl
 substituents from one to three (Laughlin, Norlund,  and Linden
 1984)  and then to decrease with the addition of a fourth butyl
 group.   In order to assess the fate of a particular tributyltin
 derivative in water one must consider the dissociated active
 form,  the TBT cation (Bu^Sn"1"),  and its major metabolites
 presumably formed by progressive debutylation to inorganic
 tin (Blunden 1984).

           Bu3Sn+ —> Bu^Sn2"1" —> BuSn3+ —> Sn4 +

               In addition,  Matthias and coworkers (1985) have
 prepared  a manuscript  for publication (currently in review  by
 Analytical Chemistry)  containing their findings of  relatively
 high  levels  of  tetrabutyltin in surface (microlayer)  water  samples
 from  Baltimore  harbor.   This species (Bu4Sn)  could  possibly be
 formed  from  microbial/photolytic transformation of  the tri-
 and dibutyl  forms  which could then be reconverted to the dibutyl
 species.   The  tetrabutyltin species may also be present in
 some paint  formulations as  an impurity in the manufacturing
 process.   Also,  butylmethyltin  (Bu3MeSn)  has been isolated
 from marine  sediment samples (ibid.).

              Analytical  methodology suitable for environmental
monitoring must,  in  view  of  the foregoing discussion,  be able to
detect  at  low levels all  butyltin and mixed methylbutyltin  species
arising from degradation  of  the TBT  cation in marine  and fresh-
water environments.  Furthermore,  because morphological and
toxicological effects have  been found to  occur in nontarget aquatic
organisms when exposed  to TBT concentrations in the parts per
trillion  (ppt) range, the analytical  methodology must have  a


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 corresponding  low  limit  of  detection.   A  number  of  speciation
 methods  (separation  and  analysis)  have  been  reported  in  connection
 with environmental monitoring  studies;  these have been reviewed
 by  Brinckman  (1983).  More  recently, Brinckman and  coworkers  have
 prepared  a manuscript which presents a  simple and rapid  method
 for the speciation of aquatic  samples using  simultaneous hydri-
 dization/extraction  with separation by  gas chromatography and
 detection by flame photometry  (Matthias et al. 1985).  In using
 100 mL salt water  samples,  the level of detection was said to be
 7 ppt of  tetrabutyltin,  7 ppt  of tributyltin, 3  ppt of dibutyltin,
 and 22 ppt of  monobutyltin.

               Among  the  methods cited in  this Support Document in
 connection with environmental  monitoring  or  bioassay studies  are
 those that measure the four  butyltin species (BunSn) and inorganic
 tin.  They are based upon preliminary extraction and purification
 using an organic solvent (benzene, tropolone, hexane, methyl
 isobutylketone) followed by  formation of  a volatile derivative
 with a Grignard reagent  (butyl-, pentylor hexylmagnesium bromide)
 or  with sodium borohydride  (hydride).  Species separation is  then
 accomplished by either gas  chromatography (GC) or programmed  warming
 in  a purge/trap (PT) system  with detection of the volatilized
 organotin derivative by  atomic absorption spectroscopy (AA),  flame
 photometric detection (FPD)  or mass spectroscopy (MS).   Detection
 limits for tributyltin (cation) in marine water columns  have  been
 reported at 7  ppt  (Matthias  et al. 1985,  using hydridization  and
 GC/FPD); 20 ppt (Maguire et  al. 1982, using  butyl or pentyl
 derivatives and either GC/FPD  or GC/AA) ;  5 ppt (Valkirs  ej: al.
 1985, using hydrization  and  PT/AA); and,  5 ppt (Huggett  1985,
 using hexyl derivatives  and  GC/FPD with confirmation by  MS).  To
 achieve these detection  limits sample volumes have  varied from
 500 mL to 2000 mL.

              Since higher levels of TBT  have usually been observed
 in  surface microlayer, fish  tissues and other sorbing media
 including sediment, analytical methods for these specimens have
 been cited with higher detection limits.  These include  60 to 150
ppt for surface microlayers  (Maguire 1982, using 100 mL  samples
by GC/FPD);  5000. ppt for marine sediment  (Maguire 1982,  using 1
gram dry specimens by GC/FPD); and, 80 ppt for fish tissue (Waldock
and Thain 1983, on tissue using flameless AA).
                               1-6

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 II-    ASSESSMENT OF RISK

       The EPA has determined that registered products  and
 applications for registration of pesticide products  containing
 the  following active ingredients in antifouling  paints:  bis
 (tributyltin) oxide, bis(tributyltin)  adipate, bis(tributyltin)
 dodecenyl succinate, bis(tributyltin)  sulfide, tributyltin
 acetate,  tributyltin acrylate, tributyltin fluoride, tributyltin
 methacrylate, and tributyltin resinate meet or exceed  the existing
 criteria  (40 CFR 162.11) and new risk  criteria (50 FR  49003)  for
 acute and chronic hazard to nontarget  aquatic organisms.

       Tributyltin compounds are very effective biocides, toxic to
 marine and freshwater organisms at extremely low concentrations.
 The  use of tributyltin compounds in antifoulant  paints, has
 resulted  in increased concentrations of TBT in harbors, marinas,
 and  estuaries.   Environmental hazard to nontarget organisms
 (i.e., nonfouling organisms such as mussels, clams,  and oysters)
 is highly probable, where  TBT concentrations have been measured
 at or near the  recorded acute and chronic  toxicity levels for
 various nontarget aquatic  organisms including commercially
 valuable  marine organisms.

       EPA has determined that the use  of pesticide products
 containing bis(tributyltin) oxide,  bis(tributyltin)  adipate,
 bis(tributyltin) dodecenyl succinate,  bis(tributyltin) sulfide,
 tributyltin acetate, tributyltin acrylate,  tributyltin fluoride,
 tributyltin methacrylate,  and tributyltin  resinate when used  in
 antifoulant paints  exceeds the risk criterion for acute and
 chronic toxicity as defined in 40 CFR  162.11(a)(3)(i)(B) and  40
 CFR  162.11 (a)(3)(ii)(C) which provide that a Special  Review
 shall  be  conducted  if a pesticide:

              "results in  a maximum calculated concen-
              centration following  direct  application
              to a  6-inch  layer of  water more than 1/2
              the acute LC$Q for aquatic organisms
              representative of the organisms likely
              to be exposed .  . ."  (40 CFR 162.11(a)(3)(ii)(B))

       Or  if use  of  the chemical:

              "can  reasonably be anticipated to  result
              in significant local  regional or national
              population reductions in nontarget
              organisms, or fatality to members  of
              endangered species."  (40 CFR 162.11(a)(3)(ii)(C))

       The  Agency has issued new Special  Review regulations  which
include revised  risk criteria.   Although these criteria are
not in  place  at  the  present,  we have concluded that  these TBT
                               II-l
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 products also meet or exceed the new risk criterion (50  FR
 49003)  because concentrations of TBT in  the  marine  and  freshwater
 aquatic environments may result

               "in residues of the pesticide  product or
               its ingredients,  impurities, metabolites,  or
               other degradation  products in  the environ-
               ment of nontarget  organisms at levels which
               equal or exceed concentrations acutely or
               chronically toxic  to such  organisms  . .  .
               at levels which produce adverse reproductive
               effects in such organisms  as determined
               from tests conducted on representative
               species or from other appropriate data."

      This  chapter consists of three sections.   The first
 discusses the toxicity of TBT to nontarget aquatic  organisms;
 the second  presents the concentrations of TBT which have been
 found in the  marine and freshwater environments; and the third
 section summarizes the potential risk posed  by the  use of  TBT
 active  ingredients in antifouling  paint  formulations.

      A.  Toxicity of TBT to Nontarget Aquatic Organisms

          1.   Introduction

               In this toxicity section,  information summarizing
 the adequacy  of  historical  bioassay tests and the acute  and
 chronic toxicity of TBT to  fish,  algae,  crustaceans,  and molluscs
 will be summarized.

          2 .   Measurement of  Toxicity

               Only recently  have  data been available on  the
 toxicity and  environmental  fate  of  tributyltin compounds,  espe-
 cially  with an interest toward delineating the  relationship which
 may exist between  the number  of  alkyl groups  (i.e.,  tributyl,
 dibutyl, and  monobutyl)  and  the  toxicities of  these  compounds.
 Many studies  were  conducted  as static bioassays with nominal non-
 measured (estimated)  concentrations.  Nominal  values do  not take
 into account  the  tributyltin  adsorption  onto  test containers
 resulting in  an  overestimate  of  the  actual available  toxicant
 in  the  solution.   Since the  concentration of  TBT toxicant  can be
 overestimated, the  LC50  reported may  underestimate  the TBT toxicity
 (e.g.,  while  the actual  LC5Q  may be  60 ppt, the reported value
may be  100 ppt since  the  TBT  concentration was  not  measured).  This
 adsorption problem  is  critical at  very low levels (i.e., < 1.0 ppb)
where a 70 percent  decrease  (almost  an order  of magnitude) has
been found between  nominal and measured  concentrations of
tributlytin (M & T  Chemical Co., Aug. 1977).
                               H-2                                 \\

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               Static renewal bioassay testing procedures may
 provide accurate estimates of tributyltin concentration if the
 test solution renewal period is brief; this procedure eliminates
 lengthy resident times and loss of tributyltin by adsorption
 and/or subsequent degradation to intermediate forms.   Flowthrough
 bioassay testing with simultaneous chemical analyses  for chemical
 speciation of the toxicant in solution is, however, a more
 desirable testing approach.

               The detection limits of TBT concentration measurement
 are of major concern.  TBT has been detected in water column
 samples using the borohydride method (Matthias et al. 1985)  as
 low as 7 ppt.  This method is most effective with large water
 sample sizes.  The Virginia Institute of Marine Science (VIMS)
 has been able to detect levels of tributyltin as low  as 2.0  ppt
 (Perkins 1985).  The determination of environmental concentrations
 in water column samples is critical to the development of a  risk
 assessment.  The inability to measure low ppt levels  of TBT  can
 result in an erroneous assessment of hazard at the sublethal
 chronic level.

               The following discussion characterizes  the concerns
 EPA has regarding tributyltin toxicity to nontarget aquatic
 organisms subsequent to their exposure to TBT concentrations now
 found in harbors, marinas, lakes, and estuaries.  Table 2
 summarizes the TBT toxicity data used to initiate the Special
 Review.  It should be noted that different investigators used
 different chemical forms (salts) of TBT in conducting the aquatic
 toxicity studies.  These included the chloride,  the bis(tributyltin)
 oxide and the methacrylate.  Although LC5Q values were reported
 using these different forms of TBT, their effect on the final
 measured or calculated result is relatively negligible.  For
 example,  the molecular weight ratio between the  bis(tributyltin)
 oxide and tributyltin chloride is only two-fold, whereas, the
 acute toxicities vary across  species of fish by  approximately
 24-fold.

           3.   Toxicity to Fish

               Acute  toxicity  testing usually measures the lethal
 (LC5Q)  or  effective  (EC^Q)  concentrations where  50 percent of the
 test  organisms are killed or  significantly affected.   Acute
 toxicity  of  bis(tributyltin)  oxide  (TBTO) to certain  freshwater
 fish  appears  to  range from 0.96  ppb to 24.0 ppb.  Reported 96-hour
 LC5Q  values  (nominal  concentrations)  for  rainbow trout (Salmo
 gairdneri),  bluegill  (Lepomis macrochirus), channel cat fish
 (Ictalurus punctatus) ,  and  mummichog (Fundulus heteroclitus)  were
 6.9,  7.6,  12.0,  and  24  ppb, respectively  (M & T  Chemical Co.
 Sept. 1976; Oct.  1976;  June 1978).   These studies were static
 nonrenewal,  using nominal  concentrations, and may not be sensitive
 indicators of  actual  toxicity  (i.e.,  actual LC50 levels could be
70 percent lower  due  to  adsorption  to test  container  surfaces and
volatilization).


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Table 2.  Test Conditions, Procedures, and Results of Tributyltin Toxicity Tests
Test Organism
FISH
Leponis
macrochirus
(Bluegill)
Salmo gairdneri
(Rainbow trout)
Ictalurus
punctatus
(Channel catfish)
Fundulus
heteroclitus
( Mumnichog )
Salmo gairdneri
(Rainbow trout)



Organotin
Ccmpound

TBTO
TBTO
TBTO
TBTO
TBTO



Effect

96-hr LCso =7.6 ppb
(5.6 to 10 ppb)
96-hr LCso =6.9 ppb
(6.27 to 7.8 ppb)
96-hr LCso = 12-° PE*
(7.3 to 20.0 ppb)
96-hr LCso =24.0 ppb
24 hr EC50 = 31.0 ppb
(loss of positive
rheotaxis). Level fron
5850 ppb to 11.7 ppb.
TBTO resulted in damage
to gill epithelium. At
11.7 ppb there was a
flattening of bile duct
columnar epithelial
cells and separation
fron connective tissue
after 5-day exposure.
Destruction of corneal
epithelium occurred
after 7-day exposure
to 11.7 ppb.
Analytical
Methods

Nominal
concentrations
Nominal
concen tra t ions
Nominal
concentra t ions
Nominal
concen tra t ions
Not reported



Type of
Exposure

Static
Static
Static
Static
Continuous
flow stain-
less steel
tanks


Concentration
Levels

5.6, 7.5, 10.0 and
14.0 ppb
4.1, 5.3, 6.8, 8.8,
and 11.0 ppb
7.5, 14.0, 18.0,
24.0 and 28.0
ppb
32.0, 42.0, and
56.0 ppb
5850 to 11.7 ppb
acetone



Reference

M & T
Chemical Co.
(Oct. 1976)
M & T
Chemical Co.
(June 1978)
M & T
Chemical Co.
(Sept. 1976)
M & T
Chemical Co.
(Sept. 1976)
Chliamovitch
& Kuhn
(1976)



-------
Table 2.  Test Conditions, Procedures, and Results of Tributyltin Toxicity Tests (Continued)
Test Organism
Cyprinodon
variegatus
( Sheepshead
minnow)
33 to 49 ran
Cyprinodon
variegatus
( Sheepshead
minnow)
17 to 25 mm





Salmo gairdneri
(Rainbow trout
yolk sac fry)










Organotin
Compound
TBTO



14C-TBTO








TBTCL












Effect
21-day LCso =0.96 ppb
Total mortality at
3.2 ppb at 14 days.


The maximum observed
bioconcentration fac-
tors were X2120 and
X4580 for the head and
viscera, respectively.
After 58 days the de-
puration of 14C-TBTO
frcm all tissues was
rapid. (52% after 7
days).
10 to 12 day LCioo =
5.0 ppb. Decrease in
growth rate at 0.2 and
1.0 ppb for 110 days.
Toxicity not observed
at 0.2 and 1.0 ppb;
hemoglobin concentra-
tion and erythrocyte
count were reduced in
blood; hyperplasia and
diminished glycogen
content observed in
liver.
Analytical
Methods
AAS measured
concent rat ions


LSC measured
concen tra t ions







Nominal
concentrations











Type of
Exposure
21-day
flow-
through
acute
testing
Exposed to
TBTO for
58 days.







110-day
continuous-
flow expo-
sure









Concentration
Levels
0.33, 0.63, 0.70,
1.5, 3.2.
acetone-methanol


0.96 to 2.07 ppb
acetone







0, 0.2, 1.0, and
5.0 ppb











Reference
Ward
et al.
(1981)


Ward
et al.
(1981)







Seinen
et al.
(1981)











-------
              Table 2.  Test Conditions, Procedures, and Results of Tributyltin Toxicity Tests (Continued)
Test Organism
Organotin
Compound
        Effect
Analytical
  Methods
 Type of
 Exposure
                                                                                             Concentration
                                                                                                 Levels
                     Reference
ALGAE
Ankistrodesmus
  falcatus
(Freshwater algae)
Skeletonema
  costatum
(Marine diatoms)
w  Thalassiosira
<*    pseudonana
   (Marine diatoms)
  TBTO
  TBTO
                       TBTO
A maximum algal bio-
concentration factor
of 3 x 1()4 was esti-
mated for TBT after
7 days.

72 hr EC50 = 0.33 ppb
             72 hr EC5Q = 1.03 ppb
 GC and FPD
   ICAP
                             ICAP
  Static
Static
Nominal
(only
stock
measured)

Static
Nominal
(only
stock
measured)
                                                                                           20 ppb
                                                                                           methanol
                                                                                           0.5, 1.0, 5.0, 7.5,
                                                                                             10.0, 15.0, and
                                                                                             25.0 ppb
0.5, 1.0, 5.0, 7.5,
  10.0, 15.0, and
  25.0 ppb
                    Maguire
                    et al.
                      (1984)
                     Walsh
                     et al.
                      (1985)
                                                 Walsh
                                                 et al.
                                                  (1985)

-------
Table 2.  Test Conditions', Procedures, and Results of Tributyltin Toxicity Tests  (Continued)
Test Organism
CRUSTACEANS
Crangon crangon
(Shrimp)

Acartia tonsa
(Copepod)



Homarus americanus
M (Lobster larvae)
i
~j
Rhithroponopeus
harrisii
(Mud crab)








Daphnia magna
(Water flea)

Organotin
Compound

TBTO


TBTO




TBTO


TBTO










TBTO

Effect

Larvae 96 hr LC50 =
1.5 ppb. Adult- 96 hour
LC5Q = 41 ppb.
72 hr EC5o = 2.1 ppb
96 hr EC5Q =1.0 ppb
144 hr EC50 =0.4 ppb


90% decrease in growth
at 1.0 ppb.

Bioaccumulation of
4400X in the hepato-
pancreas. No steady
state achieved. Accu-
mulation of TBTO from
food greater than from
only the water




48 hr LC5o =1.67 ppb
(1.01 to 2.5 ppb)

Analytical
Methods

Not reported


Measured con-
centrations
AAS


Nominal
concentra t ions

Measured con-
centration of
•t M .
C14 radio-
assay.







Nominal
concentration

Type of
Exposure

Static re-
newal every
24 hours
Static re-
newal every
24 hours
Pyrex test
tubes
Static re-
newal every
48 hours
Static re-
newal every
24 hours.
Artemia
with con-
centrations
1.23 ug
TBTO/g wet
weight were
fed to
crabs.
Static

Concentration
Levels

Not reported


0.3, 0.5, 1.0, 1.7,
and 3.0 ppb
acetone "


1.0, 5.0, 10.0,
15.0, and 20.0
ppb
0.28 ppb and
6.1 ppb









1.7, 3.0, 5.3, 7.1,
and 13.3 ppb
ethanol
Reference

Thain
(1983)

U'ren
(1983)



Laughlin &
French
(1980)
Evans &
Laughlin
(1984)








M & T
Chemical Co
(Jan. 1976)

-------
Table 2.  Test Conditions, Procedures, and Results of Tributyltin Toxicity Tests (Continued)
Test Organism
MOLLUSCS
Crassostrea
virginica
(Eastern oyster
larvae)
Crassostrea gigas
(Pacific oyster
larvae)
Mytilus edulis
(Mussel larvae)
M
v
oo Mytilus edulis
(Mussel larvae)
Crassostrea gigas
(Pacific oyster
spat)
Mytilus edulis
(Mussel spat)
Organotin
Compound
TBTO
TBTO
TBTO
TBTO
Exposure for
45 days to
tributyltin
methacrylate
leachates
Exposure for
45 days to
tributyltin
methacrylate
leachates
Effect
48 hr EC50 - 0.9 ppb
(0.4 to 1.9 ppb)
48 hr LCso =1.6 ppb
48 hr LC5o = 2.3 ppb
15 day LCso =0.1 ppb
long-term effect
Significant reduction
in growth at 0.24 ppb
Significant reduction
in growth at 0.24 ppb
Analytical
Methods
Nominal
Concent rat ion
Not reported
Not reported
Measured con-
centrations
FAAS
Measured daily
for 3 weeks
and every
other day for
the remainder
of the experi-
ment (M&T
standard
method)
Measured daily
for 3 weeks
and every
other day for
the remainder
Type of
Exposure
Static
Static re-
newal every
24 hours
Static re-
newal every
24 hours
Static re-
newal every
72 hours
Flow-
through
Flow-
through
Concentration
Levels
0.1, 0.3, 0.6, 1.0,
3.2, and 5.6 ppb
Not reported
Not reported
10.0, 1.0, and 0.1
ppb
0.24 + 0.23 ppb
for low-level and
2.62 + 1.09 ppb
for hTgh level
0.24 -I- 0.23 ppb
for low- level and
2.62 + 1.09 ppb
for hTgh level
Reference
M&T
Chemical Co
(June 1977)
Thain
(1983)
Thain
(1983)
Beaumont
& Budd
(1984)
Thain &
Waldock
(1985)
Thain &
Waldock
(1985)

-------
Table 2.  Test Conditions,.Procedures, and Results of Tributyltin Toxicity Tests (Continued)
Test Organism
Mytilus edulis
(Mussel spat)
(Continued)

Venerupis
decussata
(Clam spat)



Ostrea edulis
(European oyster
spat)



Venerupis
semidecussata
(Clam spat)


Organotin
Compound


Exposure for
45 days to
tributyltin
methacrylate
leachates



Exposure for
45 days to
tributyltin
methacrylate
leachates



Exposure for
45 days to
tributyltin
methacrylate
leachates


Effect


Significant reduction
in growth at 0.24 ppb



Growth inhibited at
2.6 ppb



Growth inhibited at
2.6 ppb


Analytical
Methods
of the experi-
ment (M&T
standard
method)
Measured daily
for 3 weeks
and every
other day for
the remainder
of the experi-
ment (M&T
standard
method).
Measured daily
for 3 weeks
and every
other day for
the remainder
of the experi-
ment (M&T
standard
method).
Measured daily
for 3 weeks
and every
other day for
the remainder
of the experi-
ment (M&T
standard
method) .
Type of
Exposure


Flow-
through



Flow-
through



Flow-
through


Concentration
Levels


0.24 + 0.23 ppb
for low-level and
2.62 + 1.09 ppb
for hTgh level



0.24 + 0.23 ppb
for low- level and
2.62 + 1.09 ppb
for high level



0.24 + 0.23 ppb
for low- level and
2.62 + 1.09 ppb
for hTgh level


Reference


Thain &
Waldock
(1985)



Thain &
Waldock
(1985)



Thain &
Waldock
(1985)



-------
                  Table 2.   Test Conditions,  Procedures,  and  Results of Tributyltin Toxicity Tests-(Continued)
   Test  Organism
              Organotin
              Conpound
        Effect
 Analytical
   Methods
 Type of
 Exposure
  Concentrat ion
      Levels
 Referenc
   Ostrea  edulis
    (European oyster
     spat)
   Crassostrea gigas
   (Pacific  oyster)
   Ostrea edulis
   .(European oyster)
                TBTO
                TBTO
                TBTO
M
O
   Crassostrea gigas
   (Pacific  oyster
     spat)
                TBTO
   Nassarius
    obsoletus
   (Mud snail)
              Alumacide
              TBT paint
Growth effected at
0.02 ppb (marginal).
At 0.06 ppb growth
rate was severely
curtailed after 10
days.

Bioaccumulation of
2000 to 6000 fold after
22 days (poor diet
was noted).

Bioaccuraulation of
1000 to 1500 fold
after 22 days (poor
diet was noted).
Spat grew poorly at
TBT  concentrations of
0.15 ppb; developed
pronounced thickening
of upper shell valve.
Bioconcentration
(Flesh) after 56 days
exposure to 0.15 ppb
was about XI1400 fold.

Anatomical abnormality
consisting of super-
imposition of male
characteristics on
female snails.
Nominal con-
centration
renewed every
day.  (M&T
standard
method).

FAAS measured
for the first
5 days of
exposure and

FAAS measured
for the first
5 days of
exposure and
on alternate
days until the
completion.

FAAS measured
(M&T Standard
method)
 Static
 renewal
 24 hours
0.02 to 2.0 ppb
Flow-
 through
Flow-
 through
0.15 and 1.25 ppb
0.15 and 1.25 ppb
Static re-
newal 24
hours
0.08 to 1.2 ppb
                                                               Not reported
               Not reported
             Not reported
    QC
Gas Chironiatography
Flame •photometric Detection
Thain &
Waldock
(1985)
Waldock,
Thain, an
Miller
  (1983)

Waldock,
Thain, an
Miller
  (1983)
Waldock
Thain
  (1983)
                     Smith
                       (1981)
                      FAAS = Flameless Atomic Absorption Spectrophotometry
                      LSC  = Liquid Scintillation Counting

-------
  (r    .         Ward  (Ward  e_t  al.  1981) found that sheepshead minnow
  fi  Pfun    "  varieqat"s) exposed  to TBTO for 21 days (measured
  riowthrough  system)  had an LC50  of 0.96 ppb and total mortality
  fh  i   ?ayS at  a  Concentration of  3.2 ppb.  It was further noted
  tnat  after exposure  to TBTO  (0.96 to 2.07 ppb) for 58 days, the
  maximum observed bioconcentration factors were 2120X and 4580X
  SS-!^    and viscera/ respectively.  He also noted that after an
  aaaitional 58  days  (i.e., 116 days total) the depuration, or
  elimination, of  TBTO from all tissue was rapid (52% after 7 days
  post-exposure).

                Chronic effects on fish were found by Seinen e_t aJ .
  11981) after subjecting rainbow trout yolk sac fry to 110 day
 exposure  to  concentrations of tributyltin chloride (continuous-flow
 exposure,  nominal concentrations).  A 10 to 12 day LC100 of 5
 ppb was estimated using concentration levels 0.2,  1,  and 5 ppb.
 Although,  young  trout exposed to tributyltin chloride concen-
 trations of  0.2  and  0.1 ppb did not exhibit mortality,  there was
 a significant  reduction in growth (40% decrease in body weight),
 decrease in hemoglobin content, hyperplasia of liver  cells, and
 diminished glycogen  content in liver.  Chilamovitch and Kuhn
 (1976) noted histological and hematological effects on  rainbow
 trout after continuous exposure to TBTO.  Damage to gill epithelium
 was  recorded  at  1.7 ppb.   At 11.7 ppb with 5  days  of  exposure,
 there was a flattening of bile duct columnar epithelial cells and
 separation of these cells from connective  tissue.   Destruction of
 corneal epithelium was observed following  7 days of exposure to
 11.7 ppb.

           4.   Toxicity to Algae

               The toxicity of tributyltin  compounds to  algae has
 not  been  intensively studied.   Maguire  et al.  (1984) noted that
 the  freshwater  algae (Ankistrodesmus  falcatus)  possesses a mechanism
 for  sequential  debutylation  of TBTO.   However,  Walsh  et al.  (1985)
 found  that TBTO inhibited  population  growth and cell  survival of
 marine  unicellular algae  Skeletonema  costatum  and  Thalassiosira
 pseudonana at low concentrations (72  hour  EC5Q  of  0.33  ppb and
 EC5Q of 1.03  ppb, respectively).

           5.  Toxicity  to  Crustaceans

              The toxicity of tributyltin  to crustaceans was
evaluated  by  several  researchers.   Laughlin (1980)  using nominal
concentrations  in a  static daily renewal,  found that  lobster larvae
 (Homarus americanus)  exhibited  a 90 percent decrease  in growth
at 1 ppb.   U'ren  (1983) calculated  a  144 hour EC$Q  for  marine
copepods (Acartia tonsa) at 0.4  ppb (measured concentrations
static daily  renewal).  Thain  (1983)  reported  96 hours  LCsg  values
for larvae  and  adult  shrimp (Crangon  crangon) at 1.5 and 41  ppb,
respectively.
                              11-11                               °*~

-------
               Tributyltin bioaccuraulation in crustaceans was
 demonstrated by Evans and Laughlin (1984) with their work on mud
 crabs (Rhithroponopeus harrisii) exposed to radiocarbon labeled
 TBTO.  The test measured the short-term effects of exposure to
 labeled test concentrations in water (9.28 ppb) and food (Artemia,
 1.23 ppb).  Four-day bioaccumulation factors ranged up to 4400 in
 the hepatopancreas with no indication that a steady state equili-
 brium had been approached.  Accumulation of tributyltin from food
 was greater than that from the water.

           6.  Toxicity to Molluscs

               Acute toxicity of TBTO to certain molluscs appears
 to range from 0.1  to 2.3 ppb.   Reported 48-hour LC^Q values for
 Eastern  oyster larvae (C_. virginica), Pacific oyster larvae
 (C_. gigas) and mussel larvae (M. edulis)  were 0.9, 1.6 and  2,3
 ppb, respectively  (M & T Chemical Co. June 1977;  and Thain
 1983).   A 15-day LC5Q of 0.1 ppb was  also reported for mussel
 larvae  (M_. edulis)  (Beaumont and Budd 1984).

               Anatomical abnormalities  attributed to tributytins
 were found in certain intertidal mud  snails  (Massarius obsoletus)
 living near yacht  basins (Long  Island Sound  and Southport,  CT).
 Smith (1981),  by investigating  this  phenomenon it was noted that
 these dioecious  snails had developed  male characteristics on
 apparently normal  female reproductive anatomy.   The correlation
 between  tributyltin concentration and these  abnormalities was
 later confirmed  in  laboratory  studies.

               European researchers have  found a significant corre-
 lation between the  TBTO concentration levels  in certain estuarine
 areas and  shellfish deformity.  Waldock  and Thain  (1983)  in  England
 found that Pacific  oyster (Crassostrea gigas)  spat (set oyster
 larvae)  grew poorly in TBTO  concentrations of 0.15 ppb,  and
 developed  pronounced  thickening  of the upper  shell valve.   Bio-
 concentration  factors,  after 56  days  exposure to  0.15  ppb TBTO,
 were  11,400X.  Alzieu  e_t  al. (1980) observed  similar malformations
 in  C. gigas  and  attributed  it to the  presence of  organotin  (TBTO
 and TBTF)  in the French  shellfish regions.  Beaumont and Budd
 (1984) noted that common  mussel  (Mytilus  edulis)  larvae did not
 survive past 5 days at  a  TBTO exposure concentration of  10  ppb,
 or  longer  than 10 days  at  a TBTO level of  1 ppb.   They concluded
 that  the high TBT levels  found at several estuarine  sites are
 associated with adult  shellfish  population reductions  in these
 areas (a 15 day LC50 of 0.1 ppb  was estimated).  Thain and  Waldock
 (1985) tested several shellfish  larvae with tributyltin methacrylate
 leachates in measured flow-through systems.   They  found  that Pacific
oyster (Crassostrea gigas), mussel (Mytilus edulis), and clam
 (Venerupis decussata) showed a significant reduction  in  growth at
0.24 ppb.  A static renewal (nominal  concentrations)  test with
spat of  the European flat oyster  (Ostrea edulis) demonstrated
that growth rate was severely curtailed following  exposure  to
0.06 ppb  TBTO.
                               II-l?

-------
               According to Waldock and Thain (1983), oysters (£.
 gigas and O. edulis) rapidly bioaccumulate TBT and reach an
 equilibrium uptake after exposure, and subsequently are slow to
 depurate this uptake.  Using measured concentrations in a 21-day
 continuous-flow system,  Waldock and Thain exposed C. gigas and
 O. edulis (10 g wet weight) to TBTO concentrations of 1.25 and
 0.15 ppb.  C. gigas accumulated a high body level of tributyltin
 that ranged from 2000- to 6000-fold.  0. edulis maintained under
 the same conditions only concentrated tributyltin from 1000- to
 1500-fold.  This twofold to fourfold difference in tissue concen-
 tration of tributyltin between species correlates with the threefold
 to ninefold difference found in the field.

               The probability of food chain accumulation was
 addressed by Laughlin, French, and Guard (1984), studying
 tributyltin uptake by marine mussels (Mytilus sp.).   TBT
 bioaccumulated from 1000 to 6000 times and was attributed more
 to food intake than to direct absorption from water or sediment.

               Given its high lipophilicity TBT is likely to be
 bioaccumulated by several organisms.  Laboratory studies may '
 underestimate the extent of bioaccumulation as they are generally
 of insufficient duration to allow all compartments within the
 test vessel  (food material, feces,  water, test organisms, vessel
 walls,  etc.)  to reach equilibrium.   Studies are needed to evaluate
 the subsequent toxicity problems associated with high bioaccumu-
 lation  of TBT.

      B.   Exposure:   TBT in the Marine and Freshwater Environment

           In  addition to review of  available bioassay and aquatic
 toxicity  data, the Agency has also  evaluated data available on
 TBT concentrations in water samples analyzed from both marine and
 freshwater environments.   Analytical methods sensitive to the ppt
 level have only recently been developed and monitoring data using
 this  new  methodology  are currently  very limited.  Some of this
 information is  shown  in Table 3.   Data from Canadian harbors in
 Lake Superior  and  Lake  Ontario are  included to provide some
 indication of  the  likely  contamination levels in Great Lakes
 harbors and other  freshwater bodies with similar water craft use
 patterns.

          The  data  from San Diego Bay,  at present,  is one of the
most systematic analyses  of  tributyltin levels  in a  U.S.  bay or
estuary (Valkirs et al.,  1985).   On the basis of informal surveys
of  local  retail outlets, Valkirs  and  coworkers  estimated that the
use of tributyltin on recreational  craft in this bay greatly
increased during the course  of  the  study.   This appears to be
reflected by a  sharp elevation  in the concentration  of TBT in the
waters near Shelter Island  Yacht  harbor where a study maximum.of
930 ppt tributyltin was measured.   This investigation in the
Shelter Island waters is particularly significant because


                              11-13

-------
 antifouling paints are likely to have been the only source of
 tributyltin in that area (i.e.  there are no drydock TBT discharges
 or other TBT point discharges identified in the area).  In relation
 to the entire San Diego Bay study,  it should be noted that,
 although tributyltin is thought to  readily bind to sediment,
 (U.S. Naval Sea Systems Command 1984) divers taking discrete
 water samples 10 cm above the bottom sediments found approximately
 the same concentrations as were detected in surface water samples.
 Figure 1 identifies the location of the sampling stations.

           The monitoring data discussed above may not be totally
 comparable to values (LCso's etc.)  reported in aquatic toxicity
 studies.  Most aquatic toxicity studies are conducted with
 filtered water into which the toxin has been initially dissolved.
 The monitoring data reviewed above  represent unfiltered water
 analyses which would,  perhaps,  include sediment bound toxin and
 even, perhaps, tributyltin which had been assimilated into plank-
 tonic organisms.   Further investigation as to whether or not a
 large proportion of aqueous TBT would be in a bound form is
 needed.   If binding is found to be  significant then the toxico-
 logical  significance will have  to be determined.

           There is also reason  to believe that the monitoring data
 might underestimate the hazard.  The Great Lakes and Chesapeake
 Bay researchers with whom the Agency has been in direct contact
 state that none of their samples have been taken in the late
 spring when freshly painted boats would be launched.   Monitoring
 by Waldock and Miller  (1983)  in an  English estuary found highest
 annual concentrations  in May (corresponding to the postwinter
 launching  of  pleasure  craft).

           In  addition  to the samples noted in Table 3 are samples
 collected  by  Virginia  Institute of  Marine Science (VIMS)  upstream
.and downstream (as influenced by tidal action)  from large
 commercial  ships  moored near the Elizabeth River in Hampton Roads.
 The concentration of tributyltin above the ships was approximately
 5  ppt.   The concentration in the surface water downstream from
 ships was  13  ppt.   Figure 2 identifies the sampling stations used
 for the  VIMS  one  day study.

          Attempts  were made  during  the Annapolis and Great Lake
 studies  to  measure, the  concentration of tributyltin in the
 surface  microlayer—where high  concentrations of lipophilic
 pesticides  have been found,  as  noted from other studies in the
 literature.   Contamination  of the water surface is presumed to be
 injurious  to  floating  fish  eggs  such as croaker,  herring,  and
 shad  species.   Unfortunately  no  completely satisfactory method of
 sampling such  a thin layer  of the water column is available.
                              11-14

-------
Table 3.
Tributyltin Concentrations (ng/L = ppt) for Water Samples)V Collected
     at Indicated Stations with Analytical Method Noted
Location
Annapolis, MD
Across harbor
frcm city docks
Marina in Back
Creek
Lake Superior
(Marathon)
Lake Ontario
(Toronto Harbor)
Lake Ontario
(Hamilton Harbor)
Lake Ontario
(Whitby Harbor)
San Diego Bay2/
Station 3-2
3 Jan 83
Station 3-3
3 Jan 83
it
14 Feb 84
Station 3-4
3 Jan 83
ii
Station 4
3 Jan 83
ii
14 Feb 84
Station 5
3 Jan 83
n
14 Feb 84
lan Diego Bay
Station 1
3 Jan 83
n
Concentration
(ppt TBT+J
34
71
20
840
160
50

50
130

100
550
180
10
110
ND
30
30
ND
ND
10
ND
10
Sample Type
Depth (Meters)
1
1
5
5
5
5

0.3-0.6
BottomV

0.3-0.6
Bottom
0.3-0.6
0.3-0.6
Bottom
0.3-0.6
Bottom
0.3-0.6
0.3-0.6
Bottom
0.3-0.6
0.3-0.6
Bottom
Analytical
	 Method 	
Hydride deriviti-
zation, GC/FPD
Hydride deriviti-
zation, GC/FPD
Pentyl deriviti-
zation GC/FPD
Pentyl deriviti-
zation GC/FPD
Pentyl deriviti-
zation GC/FPD
n

Hydride deriviti-
zation, AA^/
n

n

M
n
n
n
n
n
M
n
H
Hydride derviti-
zation, AA
n
Ref.
1
1
2
2
2
2

3
3

3

3
3
3
3
3
3
3
3
3
3
. 3
                                       11-15

-------
Table 3.  Tributyltin Concentrations (ng/L = ppt)  for Water Samples^/ Collected
             at Indicated Stations with Analytical Method Noted (Continued)
Location
San Diego (Cont.)
Station 2-1
3 Jan 83

n
20 Jun 84
7 Mar 85
25 Sep 85
Station 2-2
3 Jan 83
"
14 Feb 84
2 Jul 85
25 Sep 85
Station 2-3
3 Jan 83
11
14 Feb 84
Station 3-1
3 Jan 83
11
14 Feb 84
18 Dec 84
Elizabeth River, Near
Norfolk, Va5/
16 Sep 1985
Station 1

Station 2
Station 3
Station 4
Station 5
Station 6
Station 7
Station 8
Concentration
(ppt TBTf)


60

100
270
290
780

50
60
350
490
930

20
40
200

180
140
200
210



6

6
7
12
21
63
49
39
Sample Type
Depth (Meters)


0.3-0.6

Bottom
0.3-0.6
0.3-0.6
0.3-0.6

0.3-0.6
Bottom
0.3-0.6
0.3-0.6
0.3-0.6

0.3-0.6
Bottom
0.3-0.6

0.3-0.6
Bottom
0.3-0.6
0.3-0.6



1

1
n
n
n
it
»
n
Analytical Ref.
Method


Hydride deriviti- 3
zation, AA
3
3
3
3

3
3
3
3
3

3
3
3

3
3
3
3



Hexyl deriviti- 4
zation
n 4
4
11 4
4
" 4
4
" 4
                                   11-16

-------
I/  All water samples were whole.  No filtered samples were made.
2/  See Figure 1 for location of sampling stations.
3/  Bottom samples were taken 10 cm from the bottom by scuba  divers,
4/  AA Hydrogen flame atomic absorption spectrcphometry.
5/  See Figure 2 for location of sampling stations.

    References

    1.  Matthias et al. 1985.
    2.  Macguire et al. 1982.
    3.  Valkirs et al. 1985.
    4.  Perkins 1985.


-------
          Figure 1.  Navy Sampling  Stations  in  San Diego  Bayl/
                         3. COMMERCIAL BASIN
            2. SHELTER ISLAND
              YACHT BASIN
                                               4. COMMERCIAL
                                                 DRYDOCX
                                                    5. NAVAL STATION
                                NORTH ISLAND
                                    NAS
                1. COAST
                  GUARD
                  STATION
                           . . .  , COMMERCIAL
                                   BASIN
          YACHT REPAIR
             FACILITIES
             FISHERMAN PT
                            SAN DIEGO BAY
£/ Valkirs et al.  1985.
                                 11-18

-------
  lgure  2.  Virginia Institute of Marine Science Sampling
           Stations in the. Elizabeth River EstuaryV
I/ R.J. Huggett, Virginia  Institute of Marine Science

-------
 Both the  Annapolis  and  Great  Lakes  studies  indicated,  however,
 that the  concentration  is much  higher  in  the  raicrolayer  and
 the  Agency  is  concerned about risks that  this contamination
 may  pose.

       C.  Risk Summary

          After extensive evaluation of published  reviews,
 consultation with various Federal and  State laboratories, and
 review of EPA  data  files, EPA has concluded that tributyltin
 (TBT)  in  antifouling paints may be  a potential  hazard  to nontarget
 aquatic organisms in areas of high  boat traffic, marinas, and
 estuaries.  The toxicity and  threat of TBT exposure  to aquatic
 organisms satisfies the existing risk  criteria  (40 CFR 162.il)
 and  the new risk criteria (50 FR 49003) for acute and  chronic
 hazards to nontarget aquatic  organisms as defined earlier in this
 chapter.  A summary of  aquatic  toxicity values  is presented as
 follows:
          1)  Molluscs:  Acute LCso = °*1  to  2'3 PPb
                         Chronic effects:   0.06 to  0.24  ppb
                         Bioaccumulation:   2000- to 11,000-fold;
                           very slow depuration.

          2)  Fish:  Acute LC5Q = 0.96 to  24.0 ppb
                     Chronic effects:  0.2  to 10.0  ppb
                     Bioaccumulation:  2120-  to  4580-fold; rapid
                       depuration.

          3)  Crustaceans:  Acute LCso = 0.3  to 41.0 ppb
                            Chronic effects:  1.0 ppb
                            Bioaccumulation:  4400-fold; greater
                              accumulation  from food than  from water

          4)  Algae:  Acute LCso = 0.33 to  1.03 ppb
                      Bioaccumulation:  8000- to 30,000-fold;
                        toxic in some species, depuration  in
                        others.

          Environmental concentrations of  tributyltin are  listed in
Table 3.  Several locations appear to have  tributyltin concen-
trations equal to, or greater than, toxicity  values for  nontarget
aquatic organisms.  The following conclusions may be made  regarding
toxicity and exposure at some of the locations:
          1)  Annapolis:
tributyltin concentrations of  .034
to .071 ppb may cause acute mollusc,
and chronic mollusc effects.
                              11-20

-------
            2)   San  Diego Bay:  tributyltin concentrations of
                               .01 to  .93 ppb may cause acute
                               and chronic effects in several
                               aquatic taxa (i.e., fish, mollusc,
                               crustaceans, algae).

            3)   Lake Superior:  tributyltin concentrations of .02
                               ppb may cause chronic mollusc
                               effects.

            4)   Lake Ontario:  tributyltin concentrations of .05
                              to .84 ppb may cause acute and
                              chronic effects in several aquatic
                              taxa (i.e., fish,  mollusc, crusta-
                              ceans, algae).

            5)   Norfolk, VA:  tributyltin concentrations of .006
                             to .06 ppb may cause chronic mollusc
                             effects.

           EPA  is concerned about the acute and  chronic toxicity
 potential of tributyltin compounds to nontarget aquatic
 organisms.  Water samples have been found to contain TBT
 levels that may have direct affects on aquatic  organism popu-
 lations (molluscs).  The TBT compounds may bioaccumulate in
 aquatic biota and may pose a hazard to the food chain as they
 are passed from lower to higher trophic levels.  Adsorption
 of tributyltin compounds to sediment may have long-term toxicity
 effects on benthic browsing organisms (crustaceans,  snails,
 etc.).  Contamination of estuarine areas at sublethal concen-
 trations can influence fecundity of several aquatic  taxa from
 fish to zooplankton,  thus influencing population dynamics.
 The present use of tributyltin in antifouling paints presents
 a  potential hazard to nontarget aquatic organisms.

           The tributyltin compounds are acutely and  chronically
 toxic  to molluscs at  low levels  (0.06 to 2.3  ppb)  depending
 upon molluscs species.   A correlation between environmental
 concentrations  of tributyltin and declining populations of
 nontarget  organisms has been demonstrated in Europe  through
 the  works  of  Waldock  and Thain,  Beaumont, and Alzieu.   Laboratory
 toxicity testing,, environmental  monitoring, and bioaccumulation
 studies  have  corroborated  the conclusion that tributyltin
 antifouling paints  may  be  responsible for the decline of several
mollusc  populations.

           Based on  these findings,  Great Britain and France
have regulated  or  curtailed  the  use  of tributyltins  in antifouling
paints.  Effective  January 1,  1986  Great Britain is  banning:
a)  copolymer  formulations  containing more that  7.5%  organotin
(measured  as  tin in the  dry  paint  film)  and b)  those paints
                                        s


                                                                    3°
                             11-21                                   ^

-------
 based  on  copper  or other  antifouling systems  containing more
 than 2.5% organotin  (measured  in  the same way).   In effect  (b)
 will ban  the  supply  of existing "free association" paints while
 allowing  the  minimum use  of tributyltin compounds as a performance
 booster in other antifouling systems Great Britain will review
 these  levels  in time for  the 1987 painting season with a view
 to  reducing them in  line  with  advances in paint technology.  In
 addition, the British government  proposes to  establish an
 ambient water quality target for  organotin concentrations.

          France has recently  extended its ban another 2 years
 on  use of organotin  paints for all boats less than 25 meters in
 length.  The  French  experience shows that a ban on the use of
 TBT on pleasure craft can be highly effective.  In 1982 the
 industry producing organotin compounds measured concentrations
 in Arcachon Bay and  found levels  3 times higher than those
 known to cause malformation in Pacific Oysters.  Since the
 implementation of the first ban (1983 to 1985), the recovery
 of oysters has been  carefully monitored.   In  the Arcachon Bay
 in 1980 and 1981, C.gigas were very badly affected.  Within
 some areas, 95-100%  of the two year old oysters showed
 deformation of the shells.  In 1982, the first effective
 year of the ban, the incidence of shell deformation was down
 to 70-80% and in 1983 to  45-50%.  Even more important has
 been the reduction in number of oysters from  the same areas
 showing deformities  in both upper and lower shells.  This
 was between 70 and 90% in 1980 and 1981 but zero in 1983.
A similar recovery has occurred with spatfall; in 1980 and
 1981 there was none, but  in 1982 it was good and in 1983
 it was excellent (Vosser 1985).
                              11-22

-------
 III.
       BENEFITS
 trih .The.A9encY will perform a benefits analysis for the
 Qiim   •       during the Special Review.  The following information
 summarizes available information on the usage of tributyltin
 antifoulant paints.

       A*  Antifoulant Paint Use Pattern

           Antifouling paints containing TBT or copper compounds
 are applied primarily to vessel hulls to control the  growth  of
 rouiing  organisms.  The paints are also used to control  fouling
 organisms on docks, buoys and other marine structures.   Fouling
 is caused by the attachment of marine organisms to surfaces  that
 are submerged or in contact with fresh or salt water.  Species
 which cause fouling include algae, bacteria, barnacles,  tubeworms,
 nydroids, and sponges.   These organisms increase hull friction
 and weight which reduces speed and increases fuel consumption.
 In addition, fouling may cause deterioration to the hull coatings,
 possibly resulting in corrosion.

           Antifouling paints containing tributyltin(s) are registered
 for use  on wood, fiberglass, aluminum, steel, and cement hulls.
 These paints are applied to pleasure crafts, commercial  vessels,
 and military ships.  The U.S. Navy, the major domestic user  of
 antifouling paints, is  considering a conversion from  cuprous oxide
 to a combination of tributyltin compounds and cuprous  oxide  in
 its antifouling paints.  The Navy has proposed to use  a  copolymer
 paint with very low leach levels to minimize the the  environmental
 loading  of tributyltins.

           The U.S.  Navy is planning to replace the copper-based
 paints it is  currently  using on its steelhulled vessels  with
 copolymer antifouling paints containing tributyltin and  copper
 compounds.   Five to twenty percent of the fleet would  be treated
 annually  with full  replacement anticipated by 1991 at  the earliest.
 A  maximum annual increase of 100 vessels would be treated with an
 average of  900  pounds of tributyltin per vessel, constituting an
 additional  use  of  approximately 90,000 pounds of tributyltin
 active ingredient  per year (U.S. Naval Sea Systems Command 1984).

      B.   Tributyltin Antifoulant Paint Registrations

          As  earlier indicated, nine tributyltin compounds are
 registered  for  use  in antifouling paints.  The TBT antifoulant
paints are  formulated as single active ingredient formulations,
as multiple TBT formulations,  as any one of the TBT's in combi-
nation with copper-based compounds (usually cuprous oxide),
and as multiple  TBT's plus  copper-based compound formulations.


-------
           There are approximately 340 federally registered anti-
 fouling paints containing tributyltin active ingredients.   Review
 of these registrations indicates that the most frequently  registered
 tributyltins are bis(tributyltin) oxide (161 registrations),
 tributyltin fluoride (141 registrations), and tributyltin  metha-
 crylate (52 registrations).   The 152  single active ingredient
 formulations generally range between  5 and 20 percent active
 ingredient.  In formulations with two or more tributyltin
 compounds,  active ingredients generally range from 6 to 13
 percent.   In formulations with tributyltins and copper compounds,
 tributyltins range from less than 1 to 20 percent.  The number
 of free association paint formulations as compared to the  copolymer
 paint formulations is  not known at this time.

       C.   Usage of Tributlytin Antifoulant Paints  and Alternatives

           Current annual  domestic usage of TBT pesticides  for all
 uses  including industrial processing  water, nonindustrial
 processing  water,  wood preservatives,  and antifouling paints,
 is estimated at approximately 730,000  to 860,000 pounds of active
 ingredients.   Current  domestic usage  of tributyltins in antifouling
 paints ranges between  250,000 to 300,000 pounds active ingredient
 annually.   Bis(tributyltin)  oxide, accounts for 75,000 to  100,000
 pounds used annually,  or  approximately one-third the tributyltin
 used  as an  antifoulant.   Estimated annual antifoulant usage is
 100,000 to  125,000  pounds of  tributyltin methacrylate,  60,000
 to 70,000  of  tributyltin  fluoride, 7,500 to 15,000 pounds  of
 bis(tributyltin)  adipate,  and 5,000 to 10,000 pounds of
 tributyltin acetate.   Tributyltin acrylate and tributyltin
 resinate annual  usage  are quite  low,  on the order  of a few
 hundred pounds  each.   There  appears to be no recent usage  of
 bis(tributyltin)  dodecyl  succinate, and bis(tributyltin) sulfide.

          Many  TBT  antifoulant paints  contain copper,  or copper
 containing  compounds,  and cuprous oxide is still the main  alter-
 native  to tributyltin  in  paint formulations.   Other copper
 compounds,  such  as  metallic  copper, are also registered for use.
 Copper  compounds  are effective against the same antifouling
 organisms as  the  tributyltins;  however,  they tend  to be corrosive
 to metal, especially aluminum.   An insulative coating  is recommended
 on steel hulls prior to copper-based antifoulant paint  application.
 Label  recommendations  generally  do not recommend copper-containing
 paints  for  aluminum boat  hulls.

          Depending upon  the  type of paint and whether there  is
 copper or tributyltin  biocides  in the  formulation,  the  antifouling
 compound may be  leached from  the  paint,  activated  by periodical
 scrubbing of the outer paint  layer, or exposed by  gradual  erosion
of the paint as  the vessel moves  through the water (ablative
process).  The ablative process  is the  newest antifouling  system
 in which the pesticide is  part  of the  paint polymer.  As the
                              III-2

-------
vessel moves  through  the water, the outer paint layer is removed
and a new layer of the antifouling paint is activated.  The
advantage of  ablative paints  is that they eliminate the requirement
  r scrubbing  the underwater  hull surface.  Tributyltin paints
are n°fc  corrosive to metal such as aluminum and eliminate the
need for a protective coating between the metal and the antifouling
paint, except  when copper compounds are included in the paint
lormulation.   Tributyltins also provide longer protection against
antifoulrng organisms than the more commonly used cuprous oxide
compounds, thus reducing a ship's drydock time.

      D.  Benefits of TBT Usage

          Sufficient  data are currently unavailable to the Agency
to determine the use patterns and possible cost savings attri-
butable  to current and planned applications of TBT antifouling
paints on commercial, recreational, and nonnaval military vessels.

          The  U.S. Navy Environmental Assessment stated that the
conversion from nonablative copper-based paints to ablative
tributyltin paints will result in fuel savings, elimination of
underwater hull cleaning, and increased operational readiness.
The U.S. Navy  estimated that  use of tributylin paints would
result in a 15 percent savings in fuel consumption, amounting
to an annual savings  of $150  million once the entire fleet is
treated  with these paints.  Eliminating the need for underwater
hull cleaning  between maintenance overhauls would save an
estimated $5 million  annually.  Increased operational readiness,
which is not amenable to quantification, relates to less time
in port, longer range, and greater speed  (U.S. Naval Sea Systems
Command  1984).
                              III-3

-------
 IV*   OTHER REGULATORY CONSIDERATIONS

       A*  Expansion of Special Review

           Tne Special Review of bis(tributyltin)  oxide,  bis
               adiPate, bis(tributyltin)  dodecenyl succinate,
 srr*       n) sulfide' tributyltin acetate, tributyltin
 ^•h ^- ?'•    butyltin fl°uride, tributyltin methacrylate,  and
 crioutyitin resinate is being initiated  based on  acute and
 cnronic toxicity to nontarget aquatic organisms.   The focus of
 tne review, at this time, is on the use  of these  compounds as
 antitouiant paints.  However, if information evaluated during
 tne special Review indicates that the use of these compounds on
 other sites (including but not limited to cooling towers,
 textiles, etc.), results in exposure to  nontarget aquatic
 organisms,  or that any other criteria are met or  exceeded, the
 Special Review may be expanded to include those pesticidal uses
 as well.  Additionally, because most tributyltins pose similar
 toxicity to nontarget aquatic organisms, and several tributyltin
 compounds,  in addition to the nine compounds under Special Review,
 are registered for sites which may result in exposure to nontarget
 aquatic organisms, the Special Review may be expanded to include
 a  much larger subset of the tributyltin  compounds than the
 original nine.  These additional chemicals include:

                       Tributyltin Compounds

    Code No.                             Chemical

    083102                        Bis(tributyltin) salicylate
    083103                        Bis(tributyltin) succinate
    083104                        Bis(tributyltin) sulfosalicylate
    083106                        Tributyltin benzoate
   -083107                        Tributyltin chloride
    083108                        Tributyltin chloride complex  of
                                    ethylene oxide condensate of
                                    abietylamine
    083109                        Tributyltin linoleate
    083110                        Tributyltin monopropylene glycol
                                    malate
    083111                         Tributyltin neodecanoate
    083115                        Tributyltin isopropyl succinate
    083118                         Tributyltin maleate


     At  this  time  the  Special Review is  based on  chronic and
acute toxicity  to  nontarget  aquatic organisms; however, the
Agency  is also  concerned about the toxicity of these compounds
to humans.
                                IV-1

-------
           The animal toxicity data base to assess potential human
 toxicity is highly deficient for all TBT compounds under review
 (Doherty Memo Dec. 11, 1985) although there are some useful
 studies particularly with tributyltin oxide.  The available
 information (obtained mostly with tributyltin oxide) indicates
 concerns over immunotoxicity, teratogenicity, dermal toxicity,
 inhalation toxicity, and endocine effects.  The Agency cannot
 evaluate any human risks associated with the use of TBT compounds
 at this tjLme both because the effects are not adequately studied
 and because we have no reliable estimates of exposure either
 through the food chain (e.g. oysters) or directly through use
 (e.g.  applicators).  Should new information enable the Agency
 to identify a potential human health trigger, the Special Review
 may be expanded to include such risks.

           The Agency is also concerned  that the use of TBT
 pesticidal products may adversely affect one or more endangered
 species.  If information is obtained which supports this concern,
 the Special Review may be expanded to include consideration of
 these  hazards.

       B.  Data Call-In Notices

           The Agency also intends to issue Data Call-in Notices
 under  the  authority of section 3(c)(2)(B)  of FIFRA.   This section
 of FIFRA provides the Administrator with the authority to require
 that information be provided to the Agency,  which is determined
 necessary  to support the continued registration of a pesticide
 product.  It also provides the authority to set specific timeframes
 for conducting  the required studies and providing the data to the
 Agency.  The Agency may issue  a notice  of  intent to suspend
 registrations  of affected products if registrants fail to comply
 with the requirements of  the notices.

           Data  Call-in Notices are being developed requiring data
 for the  nine tributyltin  compounds under Special Review.  Data
 required will  include,  at a minimum,  leaching rate data by
 paint  formulation,  acute  and chronic  bioassay studies,  bio-
 accumulation and biomagnification data,  analytical methodology,
 environmental  transport data,  environmental  monitoring data,
 and monitoring  of  exposure to  workers applying and removing
 paints,  as  well  as  data quantifying TBT residues in fish and
 shellfish,  and  the  volume  of active ingredient used on the various
 sites  for which  these  products  are registered.   Additionally,  the
Agency will  conduct  a  comprehensive review of  the data needed to
 support  registrations  of  other  tributyltin pesticidal active
 ingredients  and  may  issue  additional  Data  Call-in Notices concerning
other  tributyltin  compounds.
                               IV-2

-------
 v*  BIBLIOGRAPHY


 Alzieu,  c., et al.  1980.  Evaluation des Risques due a L'emploi
      de  Peintures Anti-salissures dan les Zones Conchylicoles.
      Rev des Trav.  Inst. Pech Marit. 44:301-49.

 Beaumont,  A.R., and Budd, M.D. 1984.  High Mortality of the
      Larvae of the Common Mussel at Low Concentrations of
      Tributyltin.  Marine Pollution Bull. 15:402-05.

 Blunden, S.J.; Hobbs,  L.A.; and Smith, P.J. 1984.   The
      Environmental  Chemistry of Organotin Compounds.  In
      Environmental  Chemistry, ed. H.J.M. Bowen, pp.  51-77.
      London:  Royal  Society of Chemistry.

 Brinckman,  F.E. 1983.   Environmental Effects of Organotins.
      Unpublished paper presented at IVth International Conference
      On  Organometallic and Coordination Chemistry  of Germanium,
      Tin,  and Lead; Aug. 8-12, 1983, Montreal,  Canada.   29 p.

 Chliamovitch, Y.P., and Kuhn, C. 1977.  Behavioural,  Haematological
      and Histological  Studies on Acute Toxicity of Bis (tri-n-
      butyltin Oxide on Salmo gairdneri Richardson  and  Tilapia
      rendalli Boulenger.   J. Fish.  Biol.  10:575-85.

 Doherty, J.D. 1985. Memorandum to Linda Vlier,  dated  December 11,
      1985:   Special Review of Tributyltin Chemicals-Update on
      Tentative Identification of Potential  Toxicity  Problems,
      Request  for Exposure Information and  Survey of  Tributyltin
      Compounds Registered as Pesticides  and in  Toxicology Branch
      Files.   13 p.

 Evans, D.W.,  and Laughlin,  R.B.,  Jr.  1984.   Accumulation of Bis
      (Tributyltin)  Oxide by the  Mud  Crab, Rhithropanopeus Harrisii.
      Chemosphere 13:213-19.

 Fischer, E.G.,  et al.  1981.   Technology  for  Control  of Marine
      Biofouling—A  Review.   In Marine  Biodegradation;  An
      Tnferdisciplinary  Study,  ed.  J.D. Costlow  and R.C. Tipper.
      pp. 261-99^Annapolis,  Maryland:   Naval Institute Press.

 Hall  L.W., and Pinkney,  A.E.  1984.  Acute  and  Sublethal Effects
     'of"organotin Compounds  on Aquatic Biota:   an  Interpretative
      Literature Evaluation.   CRC  Critical Reviews  of Toxicol.
      14:159-209.

      ,.   p  1Q85    Personal  communication with R.  Hitch, dated
Huggett, R. -L*°D-   5
     October  29,  1985.

         R.B.;  Norlund,  K.;  and Linden, 0.  1984.   Long-term
     Effects*of Tributyltin Components on the Baltic Amphiped,
     Gammarus oceanicus.  Mar. Environ. Res. 12:243-71.


                                V-l

-------
 Laughlin,  R. B., Jr., and French, W.J. 1980.  Comparative Study
      of  the Acute Toxicity of a Homologous Series of Trialkyl-
      tins  to Larval Shore Crabs, Hemigrapsus nudus, and
      Lobster, Homarus americanus.  Bull. Environ. Contam.
      Toxicol.   25:802-09.

 Laughlin,  R.B., Jr.; French, C; and Guard, H.E.  1984.  The
      Physico-chemical and Physiological Bases of Tributyltin
      Uptake by  Mussels, Hytilus.  Summary of unpublished
      paper presented at the Fifty Annual SETAC Meeting; Nov.
      4-7,  1984, Arlington, Virginia.  1 p.

 M  & T Chemical  Co. Jan. 1976.  Acute Toxicity of Tributyltin
      Oxide to Daphnia magna.  Unpublished study.  EPA Accession
      No. 136469.

 M  & T Chemical  Co. Sept. 1976.  Acute Toxicity of Tri-N-
      Butyltin Oxide to Channel Catfish (Ictalurus punctatus),
      the Fresh  Water Clam (Elliptio complanatus), the Common
      Munnichog  (Fundulus heteroclitus) and the American Oyster
      (Crassostrea virginica).  Unpublished study.  EPA Accession
      No. 136470.

 M  & T Chemical  Co. Oct. 1976.  Acute Toxicity of Tri-N-Butyltin
      Oxide to Bluegill (Lepomis macrochirus).  Unpublished
      study.  EPA Accession No. 136471.

 M  & T Chemical  Co. June 1977.  Toxicitv of Tri-N-Butyltin Oxide
      (TBTO) to  Embryos of Eastern Oysdters (Crassostrea
      virginica).  Unpublished study.  EPA Accession No. 114085.

 M  & T Chemical  Co.  Aug. 1977.  Letter to Henry Jacoby of EPA
      Registration Division:  [Data Referring to the Stability
      of Bis (Tributyltin) Oxide in an Aqueous Solution].  EPA
      Accession No. 112780.

 M  & T Chemical Co. June 1978.  The Toxicity of Bis (Tri-N-
      Butyltin Oxide (TBTO) to Rainbow Trout (Salmo gairdneri).
      Unpublished.study.  EPA Accession No. 106966.

 Maguire, R.J.  1984.  Butyltin Compounds and Inorganic Tin in
      Sediments  in Ontario.  Environ. Sci. & Technol. 18:291-94.

 Maguire, R.J.;  Wong, P.T.S.;  and Rhamey, J.S. 1984.   Accumu-
      lation and Metabolism of Tri-n-butyltin Cation by a
     Green Alga, Ankistrodesmus falcatus.  Can. J. Fish.
     Aquat. Sci. 41:537-40.

Maguire, R.J.,  et al.  1982.  Occurence of Organotin Compounds
      in Lakes  and Rivers.  Environ. Sci. & Technol.  16:698-702.
                             V-2

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 Matthias, C.L., et al. 1985.  A Comprehensive Method of the
      Determinatidn "of Aquatic Butyltin and Butylmethyltin
      Species at Ultra-trace Levels Using Simultaneous Hydridi-
      zation/ Extraction with GC-FPD.  Submitted to Environ.
      j>ci. & Technol.

 Perkins. P.O. 1985.  Letter sent to L. Vlier dated Nov. 8, 1985
      [Findings on Tributyltin Used In Antifouling Paints]. 3 p.

 Seinen,  w., et al. 1981.  Short Term Toxicity of Tri-N-
      Butyltinchoride in Rainbow Trout (Salmo gairdneri Richardson)
      Yolk Sac Fry.  Sci. of the Total Environ. 19:155-66.

 Smith, B.S. 1981.  Male Characteristics on Female Mud Snails
      Caused by Antifouling Bottom Paints.  J. of App. Toxicol.
      1:22-25.	

 Thain, J.E., and Waldock, M.J. 1985.  The Growth of Bivalve Spat
      Exposed to Organotin Leachates from Antifouling Paints.
      International Council for the Exploration of the Sea.   E:28

 Thain, J.E. 1983.  The Acute Toxicity of bis (Tributyl  Tin)  Oxide
      to  the Adults and Larvae of Some Marine Organisms.  Interna-
      tional Council for the Exploration of the Sea.   E:13.

 Thayer,  J.S., ed. 1984.  Organometallic Compounds  in Living
      Organisms.   New York:   Academic Press.

 U.S.  Navy.  1984.  Environmental  Assessment of Fleetwide Use  of
      Organotin Antifouling PaintTSea Systems Command.
      Washington, D.C.

 U'Ren, S.C.  1983.  Acute Toxicity  of Bis(Tributyltin) Oxide  to
      a Marine Copepod.  Marine Pollution  Bull.  14:303-06.

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