5. BIOLOGICAL MONITORING
5.1. Method of sampling and storing biological monitoring samples 1. Blood
In occupationally exposed subjects, blood samples for assay of biological indica-tors should be obtained at the end of exposure. Since the tissues of persons not occupationally exposed show traces of various compounds (e.g. organochlorines), it is advisable to take pre-exposure blood samples with which to compare the results obtained after exposure. For pentachlorophenol and dinitro-o-cresol, ACGIH (ACGIH, 2002) and WHO (WHO, 1982b) recommend blood sampling at the end of the work shift.
Additional considerations can be made for measurements of cholinesterase activity, which varies widely from person to person. It is therefore advisable that
Table 11. Biological monitoring of occupational exposure to pesticides.
Insecticides Matrix Substances analysed References
Organophosphorus blood AChE Coye et al., 1986b;
ChE inhibitors WHO, 1986b
Alkylphosphates urine DMP, DMTP, DMDTP, Aprea et al., 1998;
DEP, DETP, DEDTP Coye et al., 1986a;
Aprea et al., 1994a;
Aprea et al., 1994b;
Aprea et al., 1996a;
Aprea et al., 1996b;
Aprea et al., 2000;
Franklin et al., 1986;
WHO, 1986b Chlorpyrifos urine 3,5,6-trichloro-2-pyridinol Fenske and Elkner,
Chlorpyrifos-methyl 1990; Aprea et al.,
1999a
Chlorpyrifos blood neurotoxic esterase (NTE) Lotti et al., 1983;
DEF lymphocytes Lotti, 1986
Acephate urine acephate, methamidophos Maroni et al., 1990
Malathion urine mono and dicarboxylic acids Coye et al., 1986a;
WHO, 1982a;
WHO, 1986b Fenitrothion urine 3-methyl-4-nitro phenol Liska et al., 1982
Parathion urine p-nitrophenol Gallo and Lawryk,
Parathion-methyl 1991; Kummer and
van Sitter, 1986
Carbamates blood AChE Coye et al., 1986b;
ChE inhibitors Huang et al., 1989;
WHO, 1986c
Benomyl urine benomyl, carbendazim, Liesivuori and
MHBC Jaaskelainen, 1984
Carbaryl blood 1-naphthol WHO, 1982a
urine
Carbofuran urine 3-hydrocaboxyfuran Huang et al., 1989
Pirimicarb urine M1 and M2 Verberk et al., 1990
Propoxur urine 2-isopropoxyphenol Brouwer et al., 1993
Syntetic pyrethroids urine DCVA, 3-PBA, 4-OH-3PBA Chester et al., 1987 Cypermethrin
Cyfluthrin urine F-PBA Zhang et al., 1991;
Deltamethrin urine deltamethrin, DBVA He et al., 1988
Fenvalerate urine fenvalerate, 3-PBA, CPBA Zhang et al., 1991;
He et al., 1988;
Aprea et al., 1997b;
Lavy et al., 1993 Permethrin urine permethrin, DCVA, 3-PBA Llewellyn et al., 1996 Organochlorine
compounds
Aldrin, Dieldrin blood aldrin, dieldrin WHO, 1989; Tordoir
and van Sitter, 1994 Chlordane blood trans-nonachlor, heptachlor Saito et al., 1986
epoxide, oxychlordane
DDT blood DDT/2,2-bis(4- Coye et al., 1986a
urine chlorophenyl)-acetic acid
Table 11. Continued.
Insecticides Matrix Substances analysed References
1,3-Dichloropropene urine cis and trans-DCP-MA Verberk et al., 1990;
Brouwer et al., 1991a;
Brouwer et al., 1991b;
Brouwer et al., 2000
Endrin urine anti-12-hydroxyendrin Kummer and van
Sitter, 1986
Heptachlor blood heptachlor epoxide Mussalo-Rauhamaa et
al., 1991
Lindane, HCH blood r-HCH, isomers of HCH WHO, 1982c; Coye
et al., 1986a
Herbicides blood 2,4-D Lavy and Mattice,
2,4-D urine 1986; WHO, 1984a
MCPA urine MCPA Kolmodin-Hedman
et al., 1983a;
Kolmodin-Hedman et al., 1983b
2,4,5-T urine 2,4,5-T Kolmodin-Hedman
and Erne, 1980
Alachlor urine DEA, HEEA Wollen, 1993
Fluazifop-butile urine fluazifop Wollen, 1993
Glyphosate urine glyphosate Lavy et al., 1992
Diquat and Paraquat blood diquat o paraquat WHO, 1984b
urine
Atrazine urine atrazine and dealkylated Catenacci et al., 1990;
metabolites Catenacci et al., 1993
Fungicides urine tetrahydrophthalimide de Cock et al., 1995;
Captan de Cock et al., 1998;
Krieger and Dinoff, 2000
Maneb urine ethylenethiourea Boleij et al., 1991;
Zineb Kurttio and Savolainen,
Mancozeb 1990; WHO, 1988;
Colosio et al., 2002 Other compounds
Chlordimeform urine 4-chloro-o-toluidine Wang et al., 1987
Chlorobenzilate urine p,p′-dichlorobenzophenone Stamper et al., 1986
Dinitro-o-cresol blood Dinitro-o-cresol WHO, 1982b;
Coye et al., 1986a
Pentachlorophenol blood Pentachlorophenol WHO, 1982b;
urine Coye et al., 1986a
DMP (dimethylphosphate); DMTP (dimethylthiophosphate); DMDTP (dimethyldithiophosphate); DEP (diethylphosphate); DETP (diethylthiophosphate); DEDTP (diethyldithiophosphate); DEF (s,s,s-tributhyl phosphorotrithioate); M1 (2-dimethylamino-4-hydroxy-5,6-dimethylpyrimidine); M2 (2-methylamino-4-hydroxy-5,6-dimethylpirimidine); DCVA [3-(2,2-dichlorovinyl)-2,2-dimethyl cyclopropanoic acid];
F-PBA (4-fluoro-3-phenoxybenzoic acid); 3-PBA (3-phenoxybenzoic acid); 4-OH-3-PBA [3-(4-hydroxy)-phenoxybenzoic acid]; DBVA [3-(2,2-dibromovinyl)-2,2-dimethyl cyclopropanoic acid]; HCH (hexachlorocyclohexane); CPBA [2-chlorophenyl)-3-methyl-1 butanoic acid]; MHBC [(methyl (4-hydroxy-1H-benzimidazol-2yl) carbamate], DCP-MA [N-acethyl-S-(3-chloroprop-2-enyl)-cysteine]
2,4-D (2,4-dichlorophenoxyacetic acid); MCPA (2-methyl-4-chlorophenoxyacetic acid), 2,4,5-T (2,4,5-trichlorophenoxyacetic acid); DEA (2,6-diethylaniline); HEEA (2-(1-hydroxyethyl)-6-ethylaniline).
subjects have at least one assessment of both pseudo and true cholinesterase activity before coming into contact with organophosphates or carbamates. These are baseline values that can be compared with post-exposure values to determine the significance of any reduction. WHO recommends three sequential basal samples (WHO, 1982a).
After exposure, samples should be obtained within 2 h for organophosphates and as soon as possible for carbamates, due to the rapid reversibility of enzyme inhibition.
5.1.2. Urine
A 24-hour urine sample (in a single container or in fractions representing various periods of the day) is generally recommended if the objective is to estimate absorbed dose. Spot urine samples can be obtained at the end of the work shift to determine absorption trends in groups, but are unsuitable for estimating absorbed doses.
More specifically, for biological monitoring of exposure to compounds with slow absorption and excretion (azinphos-methyl, chlorpyrifos, phorate, ethyl-enethiourea, pyrethroid insecticides), it may be necessary to collect urine over 24–48 h from the start of exposure or in some cases a spot sample before the work shift of the day after exposure.
Exposure of farm workers is mainly cutaneous and absorption may be slow and protracted in time. In these cases, a single urine sample at the end of the work shift may not be indicative of absorbed dose. Several studies (Aprea et al., 1994b;
Aprea et al., 1997c) have used 24-h urine samples, sometimes divided into several fractions (one during the work shift and one after the shift up to the start of work next day). If exposure extends over several consecutive days, sampling may continue for all working days of the week and for 24–48 h after the last day of work (Aprea et al., 1994a; Aprea et al., 1994b). It is advisable to continue collecting urine for a certain period after exposure; this period should be at least four times the half-life of the substance. This is useful for evaluating elimination kinetics and if possible, absorbed doses.
In any case, and especially if biological monitoring does not begin on the first day of exposure, it is advisable to make a spot urine sample before the work shift (basal sample) (Aprea et al., 1994a; Aprea et al., 1994b; Aprea et al., 2002). Basal samples are important for at least three reasons: even if a worker is not engaged in the task for which biological monitoring is carried out, he nevertheless works on the farm and can have contact with different types of pesticides; the biological indicators used can often be found in urine of subjects not occupationally exposed;
in certain cases, for example some metals (copper, manganese, arsenic), the analyte is normally found in the body.
When using spot urine samples, creatinine or specific weight should also be deter-mined in the sample to normalise the results and discard samples which are too dilute or too concentrated. When using 24-h urine samples or fractions representing various intervals of the day, the volume of urine excreted should be determined in order to define the absolute quantities of metabolites present in the sample.
The ACGIH (ACGIH, 2002) recommends urine sampling at the end of the work
shift for assay of p-nitro phenol and before the last work shift of the week for dinitro-o-cresol.
Urine can be collected in plastic containers shielded from the light with aluminium foil. Further considerations on analytical and preanalytical problems regarding bio-logical monitoring of exposure to pesticides may be found in the chapter on the general population in this volume (Aprea, 2003).