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<br /> Chemical Summary Methyl-1 ert-Butyl Ether- Microsoft Internet Explorer Page 9 of 1.1
<br /> Information on the potential neurotoxicity of MTBE to humans was
<br /> not found in the secondary sources searched Laboratory rodents
<br /> exposed to high concentrations of MTBE: exhibit neurotoxic effects.
<br /> I Humans - No information available
<br /> 2 Animals - Acutely toxic oral doses can result in hypoactivity,
<br /> munular weahnessi hYRerRrleat Prostration. lacrimation; anti n
<br /> general anesthetir effrrt at dngrs of -lTOn mg/kg (11 R. FPA
<br /> 1993a) Symptoms of inhalation exposures include hyper-
<br /> activity, ataxia, loss of righting, unconsciousness; clonia,
<br /> sporadic convulsive seizures_ The median effective concen-
<br /> tration (-EC50) for anesthesia is 200 g/m3 (55, 400 ppm) in mice
<br /> Rats exposed to 4000 ppm (6 h/day, 5 days/wk for 13 wk)
<br /> exhibited mild neurotoxic effects (transient episodes of ataxia,
<br /> reduced grip strength, and altered motor activity) (U S EPA
<br /> 1993a)
<br /> Exposure of mice and rats to target concentrations of 0, 400,
<br /> suuu, or auuu ppm M1bb ror b n/aay, 5 Gays/weer, ror up to
<br /> 18 months (mice) or 24 months (rats) resulted in several
<br /> clinical signs of neurotoxicity at the two highest exposure
<br /> levels Effects seen in rats included blepharospasm, hypo-
<br /> activity, ataxia, lack of a startle reflex, salivation; and
<br /> tremors Effects seen in mice included blepharospasm,
<br /> hypoactivity, ataxia, lack of a startle reflex, stereotypy, and
<br /> prostration (U S EPA 1993a)
<br /> (Back to TOCI
<br /> V 2NVYRONICENTAL EFTECTS
<br /> A Toxicity to Aquatic organisms
<br /> Limited information indicate that MTBE has low acute toxicity to
<br /> aquatir nrganism5 lethal roncentraticns are generally greater
<br /> than 100 mg/1, vinery-six-hour L1_50 values of 70b mg/L for Lhe
<br /> fathead minnow (Pimephales promelas), and >1000 mg/L for the
<br /> bleak Alburnus alburnus and for the harpacticoid copepod, Nitocra
<br /> spinipes, have been reported (U S EPA 1993x) Quantitative
<br /> ' gtruatua c ARtivity Rclatianuhip (WAR) aslculat.iona Predicti a
<br /> fisc, Isc.uLe 4A-5u ox 51U mg/1„ n lia,13 anranze vaiuc 1k_nv F ar . r
<br /> mg/L, a daphnia acute LC50 of 510 mg/L; a daphnia ChV of 17 mg/L,
<br /> a green algal acute LC50 of 300 mg/L, and a green algal ChV of
<br /> lq Wk (Ytp, lrl;A ipp�A] 1 An WH 41 Z1§44 mg(L hdyg l gvfi .gibed
<br /> ' err, I n,lli,alr-, .rr l lir rr,,,j Rn,in 1 rvr`nr,n I n n r ruu rnl r 0 Illrl r+F
<br /> £00 u.yfL was ,,.,L 1-Ll.a1, %1 a .�c,.L�dL�..,. �i 100 .uy/L �caLaLw.1
<br /> in at-celcrated tadpole devtlluYnLeilt and harked increases in body
<br /> wtlght of tadl,Vits ai►d flays that I,a1 L11LllC1.yV1lG IRCLGl1IU.EP1lU,1S
<br /> (U S EPA 1993x)
<br /> B. Toxicity to Terrestrial Organisms
<br /> No information was found in the available secondary sources on
<br /> thn tnuinity of MTRF to trrrnntriil arganiamn The reported rat
<br /> Heal id,Si, ualt,rS of i 6-N 9 1J/leg 111.1 La ;i0 V81llP3 ni rcy-111iL 0/1R:
<br /> sugyt:ut- L114L Lhe C.1tt=u..4d1 would auL lie auulely Lox.Lr- Lo Lerreb-
<br /> t1idl dlilitlAlb uilla5s jJie:iCi1L in VCIy lliyll L rjn4en LidLi Uil`J
<br /> C Abiotic Effects
<br /> Although MTBD is added to gasoline to improve air quality by
<br /> enhancing combustion and reducing emissions of carbon monoxide
<br /> and benzene, emissions of other pollutants, such as formaldehyde
<br /> Fnday, August 16, 1996 4 25 PM
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