Why, when I impersonate within a WCF service, can my service not load System.Transactions when I try to run a LINQ to SQL query?

[OperationBehavior(Impersonation = ImpersonationOption.Allowed)]
public void MyOperation(int arg)

<behavior name="ReceivingServiceBehavior">
    <!-- Other behaviors -->
    <serviceAuthorization impersonateCallerForAllOperations="true" />
</behavior>

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
    <system.serviceModel>

        <!-- .... -->

        <behaviors>
           <endpointBehaviors>
              <behavior name="ImpersonationBehavior">
                 <clientCredentials>
                      <windows allowedImpersonationLevel="Impersonation" />
                 </clientCredentials>
              </behavior>
           </endpointBehaviors>
        </behaviors>
    </system.serviceModel>
</configuration>

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
    <system.serviceModel>

        <!-- .... -->

        <behaviors>
           <endpointBehaviors>
              <behavior name="ImpersonationBehavior">
                 <clientCredentials>
                      <windows allowedImpersonationLevel="Impersonation" />
                 </clientCredentials>
              </behavior>
           </endpointBehaviors>
        </behaviors>
    </system.serviceModel>
</configuration>

<system.serviceModel>
    <serviceHostingEnvironment aspNetCompatibilityEnabled="false" />
    <services>
      <service behaviorConfiguration="SymitarService.ScheduleServiceBehavior" name="SymitarService.ScheduleService">
        <endpoint address="" binding="wsHttpBinding" bindingConfiguration="wsSecure" contract="SymitarService.IScheduleService">
          <identity>
            <dns value="localhost" />
          </identity>
        </endpoint>
        <endpoint address="mex" binding="wsHttpBinding" bindingConfiguration="wsSecure" contract="IMetadataExchange" />
      </service>
    </services>
    <behaviors>
      <serviceBehaviors>
        <behavior name="SymitarService.UserDirectoryBehavior">
          <serviceMetadata httpGetEnabled="true" />
          <serviceDebug includeExceptionDetailInFaults="true" />
          <serviceAuthorization impersonateCallerForAllOperations="true" />
        </behavior>
        <behavior name="SymitarService.ScheduleServiceBehavior">
          <serviceMetadata httpGetEnabled="true" />
          <serviceDebug includeExceptionDetailInFaults="true" />
          <serviceAuthorization impersonateCallerForAllOperations="true" />
        </behavior>
      </serviceBehaviors>
    </behaviors>
    <bindings>
      <netTcpBinding>
        <binding name="tcpSecure" portSharingEnabled="true" />
      </netTcpBinding>
      <wsHttpBinding>
        <binding name="wsSecure" allowCookies="true">
          <security mode="Transport">
            <transport clientCredentialType="Windows" proxyCredentialType="Windows" />
            <message clientCredentialType="Windows" negotiateServiceCredential="true" />
          </security>
        </binding>
      </wsHttpBinding>
      <mexTcpBinding>
        <binding name="mexSecure" />
      </mexTcpBinding>
    </bindings>
  </system.serviceModel>

<system.serviceModel>
    <bindings>
        <wsHttpBinding>
            <binding name="WSHttpBinding_IScheduleService" closeTimeout="01:00:00" openTimeout="01:00:00" receiveTimeout="01:00:00" sendTimeout="01:00:00" bypassProxyOnLocal="false" transactionFlow="false" hostNameComparisonMode="StrongWildcard" maxBufferPoolSize="524288" maxReceivedMessageSize="65536" useDefaultWebProxy="true" allowCookies="true">
          <readerQuotas maxDepth="32" maxStringContentLength="8192" maxArrayLength="16384" maxBytesPerRead="4096" maxNameTableCharCount="16384" />
          <reliableSession ordered="true" inactivityTimeout="00:20:00" enabled="false" />
          <security mode="Transport">
            <transport clientCredentialType="Windows" proxyCredentialType="Windows" realm="" />
            <message clientCredentialType="Windows" negotiateServiceCredential="true" establishSecurityContext="true" />
          </security>
        </binding>
      </wsHttpBinding>
    </bindings>
    <behaviors>
      <endpointBehaviors>
        <behavior name="ImpersonationBehavior">
          <clientCredentials>
            <windows allowedImpersonationLevel="Impersonation" allowNtlm="true"/>
          </clientCredentials>
        </behavior>
      </endpointBehaviors>
    </behaviors>
    <client>
      <endpoint address="https://server:444/SymitarService/ScheduleService.svc"
                binding="wsHttpBinding"
                bindingConfiguration="WSHttpBinding_IScheduleService"
                contract="Symitar.ScheduleService.IScheduleService"
                name="WSHttpBinding_IScheduleService"
                behaviorConfiguration="ImpersonationBehavior"
                >
        <identity>
          <dns value="localhost" />
        </identity>
      </endpoint>
    </client>
  </system.serviceModel>

[OperationBehavior(Impersonation:=ImpersonationOption.Required)]