By Ashley Follette (SCNM ND student), based on the powerpoint slides of Dr. Walter Crinnion ND

Solvent / Uses / Exposure/Sources / ½ life / Adverse effects
Benzene / -made from petroleum
-top 20 cmpds
-used to make styrene, cumene (resins), cyclohexane (synthetic fibers)
-used in mfcr of drugs, pesticides, dyes, cmpds / -Airborne: combustion of gasoline; cig smoke (32 cigs/d = 1.8mg benz/d), pumping gas, indoor air freshners
-Other: glue, paint, furn. wax, detergent; house w/ attached garage; outside air near chem. & paint plants
-well water contam. (from leaking gas station storage tanks) / -biphasic: initial clearance from body is 1 hr, what’s left takes 24 hrs
-neurotoxic, but not bio-cumulative / -bone marrow probs: anemia, thrombocytopenia, leucopenia, cancers (acute myeloid leukemia(AML) & aplastic anemia)
-↑risk of leukemia, breast can, multiple myeloma, Hodg.lymph, & NHL
-male infertility
-reduced infection fighting (from airborne exp)
-abnorm. long periods, female infertility, ↑miscar rate
-UPS drivers, airport workers, flight attendants, freq flyers
Ethylbenzene / -found naturally in crude oil
-used to make styrene
-used as solvent & additive in gas & aviation fuel / -gas & gas exhaust
-carpet & tile glues
-paints & varnishes (high in marine paints)
-cigarette smoke
-contaminated groundwater
-dermal absorption for spray painters / -12 hours
-majority should be cleared through urine w/in 2 days of exposure
-half-life can be expended if more solvents are involved / -presence of ethylbenzene & xylene prolong the time toluene is present in the blood
-neurotoxic “brain fog” (chronic or acute CTE)
-bone marrow probs (same as benzene)
-hearing loss
-↑ chemical reactivity (MCS)
Xylene
(dimethylbenzene) / -top 30 chems produced in U.S.
-“safe” replacement for benzene in gas (doesn’t cause aplastic anemia)
-printing, rubber, & leather industries
-cleaning agent, in paints, paint thinners, & varnishes / -gas
-auto exhaust
-cigarette smoke
-paint & varnish fumes
-dermal exposure from contact w/ gas & furniture finishes / -majority absorbed (mostly inhaled) leaves body w/in 18 hrs
-small amt. (4-10%) stored in fat – takes longer to exit body
-takes longer to clear from a person w/ more adipose tiss / -neurotoxic “brain fog” (acute or chronic CTE)
-fatigue
-headache, depression, mood changes
-adversely affects learning, behavior, & memory in offspring exposed in utero
-from 2 studies done, the 3 most common symptoms from neurotoxicity of xlyene: fatigue, dry throat, increased thirst
-3 isomers of xylene (dimethylbenzene): meta-xylene, othro-xylene, para-xylene
-mixed xylene is a mixture of the 3 isomers & usually contains 6-15% ethylbenzene
Toluene
(methylbenzene) / -high production chem. from crude oil
-as a solvent
-to make other chemicals (benzene, trinitrotoluene, toluene diisocyanate)
-minor component of gas & octane-boosting additives
-paint, paint thinners, fingernail polish, lacquers, adhesives, rubber in some printing, leather tanning, latex paint, Glade air freshener / -fumes of paints, glues, solvents, gas
-working in places where these cmpds are used regularly (painters, nail salons, etc)
-nail polish, stain removers, carburetor cleaners, cigarette smoke, auto exhaust
-higher levels found in smokers, ppl who drink regularly, ppl exposed to pain & lacquer thinners / -aspirin, benzene, & alcohol block the clearance of toluene & increases its blood levels
-6 hrs / -most common symptoms: fatigue, impaired memory, impaired concentration, irritability, headaches, labile mood, depression
-neurotic behavior, dizziness, insomnia
-“checkers” – have to go back & check things that they have already done (ex: turning off stove)
-psychomotor coordination problems
-study: neurotoxicity amongst printers – 3 most common symptoms: fatigue, impaired mem, impaired concen
-shipyard painters: high scores for neurotic behavior, signif. probs w/ STM, concen, fatigue, dizzy, insomnia; press. in chest & perspiration w/o work; “checkers”
-Ppl w/ 15 min exposure to 15 ppm showed cognitive impairments, esp. short & long-term mem, psychomotor coord.
-Retired painters still have CTE (low motor ability, reasoning, & mem)
-female workers – more probs w/ manual dexterity, visual scanning, verbal memory – the toxicologist & enviro ppl said these women did not fit into toluene toxicity category
Styrene / -high production chem. (>13 bill lbs produced in 2006 US)
-in polysterene plastics & resins that make: plastic packaging, disposable cups/containers, insulation, adhesives, fiberglass, synthetic rubber & latex
-benzene & ethylbenzene used to make styrene / -gas
-auto exhaust
-cig. smoke
-paint & varnish fumes
-emissions from photocopiers & laser printers (getting more exposure from home offices)
-dermal exposures from gas, paint, furniture finishes
-ingestion exposure: food that has been stored or heated in Styrofoam / -8-9 hrs in blood
-2-4 days in adipose
-presence of toluene & trichloroethylene reduce metabolism of styrene / -impaired rxn time & vestibular fcn
-reduces MAO-B activity in platelets
-cognitive disorders: short-term verbal mem impairement, ↓ verbal learning, impaired logical mem
-most frequent symptoms: ha, dizzy, light-headed, fatigue, irritability, mem loss, feeling “drunk”
-impaired color vision
-study: workers w/ 8.6 yrs exp – highest symptom: impaired logical mem, visualmotor, & visualconstructive ability
-study: dizziness very consistently found in those exposed (very uncommon in those not exposed); to test pt, have stand on tip-toes w/ eyes closed
Trichloroethylene / -dry cleaning
-ground water in Tuscon / -very hard to clear bec it is a chlorinated solvent – gets stored in fat, brain fat! / -cranial nerve effects, esp. trigeminal
-persons w/ TCE contaminated well water: ↑ hearing impairment (signif.), ↑ speech impairments, ↑ resp. probs
-multiple neurobehavioral changes (response time, sway, mem, visuospatial & movt tests)
Hexane / -commonly used solvent (consists of n-Hexane & its isomers of 2-methylpentane & 3-methylpentane)
-in glues, adhesives, paints, gas, jet fuel / -gas, auto exhaust
-quick-drying glues
-jet fuel & exhaust
-presence of methylpentanes w/o n-hexane typically indicate that exposure is neither recent nor ongoing (historic exposure bec n-hexane became methylpentane) / -acute exp – CNS disturbances: ha, mental irritability, paresthesias
-chronic exp – peripheral neuropathy – muscle weakness, loss of sensation, impaired gait
-can cause demyelination & nerve fiber degen.
-balance probs & CTE
-distal axonal swelling leading to neuropathies & muscular atrophy
-abnormal color vision
-abnormal sway testing (vestibulocerebellar & spinocerebellar changes)
-farmers w/ regular exposure had levels lower than drivers regularly exposed to exhaust fumes (both were 95th percentile) – drivers exposed to a lot!!!
-study: 95th percentile level for the presence of n-hexane in blood as range of 403-812 ppb – ridiculously high levels! Ubiquitous & hard for body to clear!
Formaldehyde / -histology technicians: reduced dexterity, balance, coord, choice performance on neurobehavioral testing; 10X increase in lightheadedness & dizziness; 5X increase in loss of balance; pronounced symptoms in older ppl
-long-term exposure: excessive fatigue, somnolence, ha, mem trouble, irritability, mood instability, cognitive difficulties