TOXICOLOGICAL PROFILE OF XYLENE

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TOXICOLOGICAL PROFILE OF XYLENE

• V. NECSULESCU
• NHLS UNIVERSITAS
• ANATOMICAL PATHOLOGY DEPARTMENT
• ELECTRON MICROSCOPY UNIT
• BLOEMFONTEIN

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INTRODUCTION

• In the past the prime objectives in laboratories
  were
• - Specimens integrity
• - Results accuracy
• Now with the accreditation system important
  issues are also
• - The health care workers
• - Environmental protection and preservation
• Exposure to toxic substances occurs in all
  laboratories.
• One of the most commonly used reagents in the
  laboratory with toxic effects is xylene.

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REASONS AND AIMS

• REASONS
• Xylene is used daily in large quantities in the
  laboratories, and the risks of accidents, very
  high.
• Xylene is harmful to our health and environment.
• AIMS
• To have proper knowledge about
• The physical and chemical characteristics of
  xylene
• The negative effects of toxic exposure and the
  safety regulations thereof.
• To determine the technologists to be more open to
  new and less harmful products which may replace
  the xylene in the laboratory

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PHYSICAL AND CHEMICAL CHARACTERISTICS OF XYLENE

• PHYSICAL CHARACTERISTICS
• Liquid colorless, sweet-smelling at RT
• Evaporates fast
• Inflammable
• CHEMICAL CHARACTERISTICS
• Aromatic hydrocarbons
• Chemical formula C6H4(CH3)2
• There are three types of isomeri- ortho, meta,
  para
• Xylene does not mix with water
• Xylene does mix with alcohol, acetone, etc.

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WHERE AND HOW XYLENE OCCURS

• NATURALLY
• Petroleum
• Coal tar
• During forest fire
• Automobile exhaust
• Cigarette smoke
• Gasoline
• ARTIFICIALLY
• Industrial synthesis
• Rubber
• Solvent, thinner for paint and varnishes
• Leather industry
• Plastics
• Synthetic fibers
• Coating of fabrics and papers
• Laboratories
• Accidental spillage
• Chicken eggs stored in polystyrene conatiners

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WHO ARE EXPOSED

• Biomedical laboratory workers
• Painters and paint industry workers
• Distillers of xylene
• Wood processing plant workers
• Automobile garage workers
• Metal workers
• Furniture refinishers

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EXPOSURE CHARACTERISTICS

• PERIOD OF EXPOSURE
• Short term exposure 14 days or less
• Long term exposure 1 year or more
• PATHWAY OF EXPOSURE
• Breathing
• Ingestion
• Contact
• Absorption
• DETERMINANT FACTORS OF NEGATIVE EFFECTS OF
  EXPOSURE
• Dose (Concentration)
• Duration
• Pathway of exposure
• Other chemical exposures
• Individual characteristics (age, gender,
  nutritional status, family traits, life style,
  state of health)

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NEGATIVE EFFECTS OF XYLENE EXPOSURE AND TOXICITY
(I)

• HUMANS
• SHORT TERM EXPOSURE (high concentration)
• Headaches
• Euphoria
• Lack of muscle coordination
• Dizziness
• Confusion
• Seizure activity
• Change in the sense of balance
• Irritation of the skin, eye, nose, throat
• Breathing difficulty (shortness of breath, chest
  pain, wheezing)
• Tachycardia
• Arrhythmias (ventricular failure)
• Nausea
• Vomiting
• Abdominal pain

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NEGATIVE EFFECTS OF XYLENE EXPOSURE AND TOXICITY
(I)

• HUMANS
• LONG TERM EXPOSURE
• Memory loss
• Anatomically and functionally changes in liver
  and kidney
• Balance problems
• Epistaxis (nose bleeding)
• Tinnitus
• Muscle weakness
• In the fetus delayed growth and development is
  evident
• The same concentration is also harmful to the
  mother

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NEGATIVE EFFECTS OF XYLENE EXPOSURE AND TOXICITY
(II)

• ANIMALS
• SHORT TERM AND HIGHT CONCENTRATION EXPOSURE
• Muscular spasms
• Incoordination
• Hearing loss
• Behavioral changes
• Changes in organ weight
• Changes in enzyme activity
• Death

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NEGATIVE EFFECTS OF XYLENE EXPOSURE AND TOXICITY
(III)

• ?Long term exposure to low concentration has not
  been well studied.
• In USA it referred to as Sickhouse syndrome
• The carcinogenity could not be demonstrated

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NEGATIVE EFFECTS OF XYLENE EXPOSURE AND TOXICITY
(III)

• ENVIRONMENT
• Contamination of underground water
• Contamination of drinking water
• It remains underground for months or years
• It is absorbed in small amounts by plants, fish
  and birds
• Small living organisms in soil and underground
  water may transform it into other less harmful
  compounds.
• EQUIPMENT
• Dissolve paint from the apparatus
• Melt plastic containers for specimens
• Melt pencils and pens
• Melt protection equipment (gloves, spectacles,
  windshields)
• Dissolve the glue resulting in the detachment of
  the stickers with pertinent patient information
• Fuse the ink on the stickers making the writing
  illegible

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TOXICITY OCCURANCE

• ACCIDENTAL (In working places)
• Inhalation
• Ingestion
• Absorption through the skin
• DELIBERATE
• Inhalation (sniffing glue-mixture of aromatic
  hidrocarbons)

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FIRST AID MESURES

• Remove patient from the area of contamination
• Remove patients clothing if are soiled with
  toxic substances
• Examine the skin for chemical contamination or
  irritations
• Immediate irrigation of the area of contact
  (skin, eyes, mucous membranes)
• Prompt administer of ventilation support oxygen
• The rescuer should avoid mouth-to-mouth
  resuscitation if the patient had inhaled the
  fumes

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LABORATORY TESTS FOR TOXICITY

• BLOOD AND URINE TESTS
• (essential to monitor the function of liver and
  kidney)
• ARTERIAL BLOOD GASES (ABGs)
• Acidosis
• Hypoxemia
• Hypercarbia
• SERUM ELECTROLYTES
• Hypocalemia
• Hyperchloremia
• Metabolic acidosis
• GLUCOSE
• Hypoglycemia (must be ruled out as a cause of
  decreased mental status)
• BLOOD UREA NITROGEN (BUN)
• CREATININE
• TOXICOLOGICAL TESTS (to detect other substances
  with similar symptoms if there is a history)
• ECG essential for cardiac monitoring

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SAFETY EXPOSURE LIMITS FOR XYLENE

• OCUPATIONAL EXPOSURE STANDARDS (OES)
• 100 ppm (100 parts of xylene per million parts of
  air) over a workday up to 8 hours long in a
  40-hour workweek.
• MAXIMUM EXPOSURE LIMITS (MEL)
• 150ppm, maximum of 15 minutes

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HEALTH AND SAFETY AT WORK ACT

• No smoking or flames permitted in the area where
  working with xylene.
• The volume kept in the laboratory should only be
  enough for daily use.
• The stock for daily use should be stored in
  metal-proof cabinets
• Bulk stocks should be maintained in
  purpose-build, fire-resistant rooms with heavy
  metal fire-proof doors.
• The room should be sunken below floor level or
  have a metal lip at the entrance to prevent the
  escape of burning liquid.
• An automatic carbon dioxide extinguisher system,
  which is triggered by heat, should be fitted in
  the store rooms.
• Discarded xylene should be stored in special
  drums or dispersed of by means of a special
  drainage system.
• Highly corrosive or oxidizing agents like nitric
  acid must never be stored with xylene or other
  solvents.
• Fume cupboards and safety cabinets are required.
• To limit exposure, using personal protective
  equipment is obligatory.

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PRECAUTIONS AND COMMON SENSE

• Good organization
• Clean and tidy laboratory
• Well planned methods should be adhered to,
  irrespective of work load
• Laboratory coats must be worn with buttons
  fastened
• Eating, drinking and smoking should be forbidden
  in the laboratory
• Hands must be washed after handling chemicals and
  before leaving the laboratory
• Protective equipment must be used
• All glassware should be of good quality and the
  broken or damaged items discarded

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CONCLUSIONS

• The laboratory workers have a legal and ethical
  responsibility to provide and maintain safety not
  only for themselves but also for their fellow
  workers and everyone entering the laboratory.
• Storage and discarding of xylene are important
  issues and the impact thereof on environmental
  protection is the concern of everyone.
• Xylene is toxic and harmful but respecting the
  safety regulations and with the existent
  equipment protection in the laboratory the
  toxicity do not rich the dangerous level.

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Rules for Laboratory Workers

• 1. When you don't know what you're doing,
  do it neatly.
• 2. Experience is directly proportional to the
  equipment ruined.
• 3. Experiments must be reproducible. They should
  all fail the same way.
• 4. A record of data is essential. It indicates
  you have been working.
• 5. Do not believe in miracles, rely on them.
• 6. Teamwork is essential in the lab. It allows
  you to blame someone else.
• 7. Always leave room to add an explanation when
  it doesn't work.