pentachlorophenol (pcp) in wood treatment_gavri_iulia

8/10/2019 Pentachlorophenol (PCP) in Wood Treatment_Gavri_Iulia

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PENTACHLOROPHENOL PCP) IN WOODTREATMENT

Academic: Student:Conf. dr. ing. Castelia Cristea Gavri Iulia-Teodora

BABE -BOLYAI UNIVERSITY Faculty of Chemistry and Chemical Engineering

Advanced Chemical Process Engineering


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1. INTRODUCTION

Wood is a hard, fibrous structural tissue found in the stems and roots of trees and otherwoody plants. It has been used for thousands of years for both fuel and as a construction

material .

The wood-preserving industrytreats lumber with variouschemicals to protect against

insect damage and decay.


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Wood Chemicals:

-Creosote-Pentachlorophenol (PCP)-Metal salts made from chromium, copper, arsenic, or zinc


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2. PENTACHLOROPHENOL (PCP)

- Organochlorine compound used as a pesticide and a disinfectant.- First produced in the 1930s, it is marketed under many trade names.- Found in two forms: PCP itself or as the sodium salt of PCP


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3. PROCESS DESCRIPTION

Wood preserving using PCP employs either a pressure process (Figure1) or a thermal process (Figure 2) to impregnate the wood with thepreservative chemical.

Fig. 1- Flow Diagram - Wood Preservation Using Pentachlorophenol PressureProcess

Fig. 2- Flow Diagram - Wood Preservation Using Pentachlorophenol Thermal Proce
http://www.ec.gc.ca/inrp-npri/29B3E589-5068-429D-B710-2BF98BC26AD8/img410_FINAL-Wood-Pres-Guid[1].gifhttp://www.ec.gc.ca/inrp-npri/29B3E589-5068-429D-B710-2BF98BC26AD8/img49_FINAL-Wood-Pres-Guide[2].gif


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4 HEALT AND ENVIRONMENTAL IMPACT RISK ASSESSMENT

Fig.3 - Health Data from Inhalation Exposure

ACGIH TLV --American Conference ofGovernmental and Industrial Hygienists'threshold limit value expressed as a time-weighted average; the concentration of asubstance to which most workers can beexposed without adverse effects.LC 50 (Lethal Concentration 50 )--A calculatedconcentration of a chemical in air to whichexposure for a specific length of time is expectedto cause death in 50% of a defined experimentalanimal population.NIOSH IDLH -- National Institute of OccupationalSafety and Health's immediately dangerous tolife or health concentration; NIOSHrecommended exposure limit to ensure that aworker can escape from an exposure conditionthat is likely to cause death or immediate ordelayed permanent adverse health effects orprevent escape from the environment.NIOSH REL --NIOSH's recommended exposure

limit; NIOSH-recommended exposure limit for an8- or 10-h time-weighted-average exposureand/or ceiling.OSHA PEL --Occupational Safety and Health

Administration's permissible exposure limitexpressed as a time-weighted average; theconcentration of a substance to which mostworkers can be exposed without adverse effectaveraged over a normal 8-h workday or a 40-hworkweek.


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5. ALTERNATIVES

For impregnation of wood products, there are several satisfactoryalternatives. Wood products that do not need impregnation can be used,or other impregnation agents or other surface treatment less hazardousto health and the environment can be used.

It is also possible to use other materials such as steel (which can berecovered), fibreglass, cement/concrete which has a lifetime that isalmost twice as long as PCP-processed wood.

Some materials do not need the level of maintenance as impregnatedwood, and do not need to be processed as hazardous waste.

PCP is used in yarn and textiles to reduce mould and insects. There arealternative chemicals less hazardous to health and the environment,which have similar effects on mould and insects.


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6.CONCLUSIONS

PCP is a priority hazardous substance, and national goals havebeen established for phasing it out.

Documentation shows that PCP has serious effects on health andthe environment, and it has been detected in the environment.

Products with PCP also contribute to emissions of dioxins andfurans, which have serious effects on health and the environment.The proposed regulation will fill this gap in the current regulationof PCP.

In addition, dioxins are known to be generated from PCPphotochemically, by burning of treated wood, and via thecorresponding predioxins, but any contribution of these sourcesto human exposure has not been evaluated.


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7. RECOMANDATIONS

The following recommendations are intended toimplement three general objectives:

1.The exposure of humans and economic animals toPCP and its impurities must be defined andminimized.

2. The indiscriminate use of PCP products (e.g., mosthome uses) should be limited, in favorof essential uses.

3.The quality of technical PCP should be improved.


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Thanks for yourattention!

pentachlorophenol (pcp) in wood treatment_gavri_iulia

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