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Possible influence of lipid content on levels of organochlorine compounds in mussels from Galicia coast (Northwestern, Spain). Spatial and temporal distribution patterns.

Influence of lipid content of mussel on levels of organochlorine compounds (polychlorinated biphenyls [PCBs] and OC pesticides) has been studied. Mussel samples coming from three sites in Galicia coast (Northwestern, Spain), Moaña and Cangas C from Ría de Vigo and Barallobre from Ría de Ferrol, collected monthly in the period from November 2000 to October 2001, have been analysed. Organochlorine compounds, PCBs (IUPAC nos. 31, 28, 52, 101, 118, 153, 105, 138, 156 and 180) and OC pesticides (pp'-DDE, op'-DDT, pp'-DDT, aldrin, isodrin and endrin) have been extracted by means of Soxhlet and determined by using gas chromatography (electron capture detector [ECD]) and gas chromatography-mass spectrometry. Statistical analysis has been performed using the SPSS statistical package. Few compounds were correlated with lipid content (Pearson product-moment correlation); for samples coming from Barallobre, only the individual PCBs 31, 28, 52 (tri- and tetrachlorinated biphenyls) and 180 (heptachlorinated biphenyl) presented a significant correlation; for Moaña samples, two cyclodiene pesticides, endrin and isodrin, presented a slight significant correlation with lipid content. From these results, it is deduced that the normalization of the concentration of organochlorine compounds to the lipid content is not necessary, in this way, avoiding possible error sources associated to the analytical determination of the lipid contentor reproductive status of mussel. Multivariate techniques (PCA) have been employed in order to study spatial and temporal distribution patterns of organochlorine compounds. The great differences found in studied samples are mainly related to spatial distribution: separations between estuarine bays (samples coming from Ría de Vigo and Ría de Ferrol) and between rural and urban zones (samples coming from Moaña and Cangas C and samples from Barallobre, respectively).

Animals↗

Chlorinated cyclodiene pesticide residues in blue mussel, crab, and fish in the Gulf of Gdańsk, Baltic Sea.

Chlordane components (CHLs) and their metabolites (heptachlor, cis-heptachlor epoxide, U82, MC4, trans-chlordane, MC5, cis-chlordane, MC7, oxychlordane, MC6- and trans- and cis-nonachlor) and aldrin, dieldrin, endrin, isodrin, endosulfan 1, endosulfan 2, and mirex were quantified in the soft tissues of blue mussel, a whole crab, and whole fishes collected from the spatially different sites in the Gulf of Gdańsk. Six to twelve chlordane compounds and metabolites and dieldrin were detected in all organisms examined while aldrin, endrin, isodrin, endosulfans 1 and 2, and mirex were not found above the detection limit of the method. The lipid weight based concentrations in Baltic biota were relatively small and ranged from 12 to 150 and 7.6-77 ng/g, while between 0.16 and 6.8 and 0.10-6.6 ng/g in fresh tissue, respectively. The profile (%) of chlordane compounds was very similar between various fish species with trans-nonachlor (28 +/- 17), cis-chlordane (23 +/- 18), oxychlordane (13 +/- 7), and heptachlor epoxide (11 +/- 5) as major constituents and was totally different in crab with oxychlordane as the most dominating (>65%) compound. Blue mussel, lamprey, and three-spined stickleback exhibited a smallest ability to metabolize CHLs, and such fishes as cod, lesser sand-eel, sand-eel, pikeperch, perch, round goby, flounder, and herring showed a slightly better ability, while crab was able to effectively metabolize most of CHL compounds except trans-nonachlor. A value of the quotient of the trans-nonachlor to cis-chlordane concentrations (N/C quotient) was 1.0 in blue mussel, 3.1 in crab, and between 0.9 and 1.8 in fish. Both the small concentrations of CHLs in all organisms and the values of N/C quotients close to 1 imply on a long-range aerial transport through movement of the air masses from the remote regions of the northern hemisphere as a main source of this pesticide in the Gulf of Gdańsk. The interdependences between the CHL profiles for various fish species and between different sampling sites were examined using the principal component analysis (PCA) method. Applying the PCA model the first four significant components explained 90% (43% + 23% + 15% + 8%) of the total variance in the data matrix.

Animals↗

Supercritical fluid extraction of organochlorine pesticides in eggs.

The efficacy of supercritical fluid extraction (SFE) for the recovery of 16 common organochlorine pesticides (OCPs) from liquid whole eggs was investigated by employing supercritical carbon dioxide (SC-CO(2)) without the use of a solvent modifier to minimize interfering coextractives. The OCPs tested included aldrin; alpha-, beta-, delta-, and gamma-BHCs; p,p'-DDD, -DDE, and -DDT; dieldrin; endosulfans I, II, and sulfate; endrin; endrin aldehyde; heptachlor; and heptachlor epoxide. The SFE conditions were as follows: 10000 psi (680 bar), 40 degrees C, SC-CO(2) flow rate of 3.0 L/min with an extraction time of 40 min for a total of 120 L of CO(2). The OCPs were trapped off-line in an SPE cartridge containing Florisil and then eluted by an acetone/hexane mixture and analyzed by gas chromatography-electron capture detection (GC-ECD). Recovery studies were carried out on homogenized eggs fortified at the 0.05, 0.10, and 0.20 ppm levels. At the lowest level, 0.05 ppm, recoveries ranged from 81.8 to 108.3%, with CVs < 9.8%. All recoveries were significantly higher than those obtained by an AOAC/FDA solvent extraction method. Eggs containing incurred endosulfan I were also effectively extracted by SFE. This study suggests that the application of SFE for the extraction of OCPs from eggs will result in significant savings in analysis time and lower solvent use and disposal costs compared to conventional solvent extraction procedures.

Animals↗

Residues of organochlorinated pesticides in eggs of water birds from Tai Lake in China.

The levels of organochlorine compounds in eggs of water birds from the colony on Tai Lake in China were studied. The eggs were collected in 2000 and belonged to the following species: 65 samples of black-crowned night heron (Nycticorax nycticorax), 36 samples of little egret (Egretta garzetta), 26 samples of cattle egret (Bubulcus ibis) from 13 clutches and 43 samples of Chinese pond heron (Ardeola bacchus) from 17 clutches. Dichlorodiphenyltrichloroethane (DDT) and its derivates (DDE and DDD), hexachlorocyclohexane (HCH) and its isomers (alpha-HCH, beta-HCH, gamma-HCH, delta-HCH), heptachlor, heptachlor epoxide, aldrin, dieldrin, endrin, endrin aldehyde, alpha-endosulfan, beta-endosulfan, and endosulfan sulfate were determined in the laboratory by gas chromatography. The data showed that DDE had the highest levels in all the samples, followed by beta-HCH. The mean levels of DDE among the water bird species were in the order as follows: black-crowned night heron (5464.26 ng/g, dry weight) > Chinese pond heron (2791.12 ng/g, dry weight) > little egret (1979.97 ng/g, dry weight) > cattle egret (660.11 ng/g, dry weight). DDT and its metabolites accounted for 90% of the total organochlorines, except that it was only 73% for cattle egret. The differences of the residue among the bird species were statistically significant and could be attributed to their variations in prey and habitat. Although the DDE burdens in Tai Lake were much lower than 8 microg/g (wet weight) which are thought to have significant adverse effects on black-crowned night herons, they would be expected to increase the risk of adverse effects on survival of chicks of herons and egrets, particularly black-crowned night heron, based on the critical value of 1 microg/g (wet weight) DDE. The burdens of HCHs in this study were higher and the cyclodienes were lower than those found elsewhere.

Animals↗

An assessment of the bioavailability of persistent organic pollutants from contaminated soil.

A procedure to assess the bioavailability of persistent organic pollutants (POPs) from soil samples has been developed. The procedure is based on the use of simulated in vitro gastrointestinal extraction to remove POPs from soil matrices. The level of recovery, using this approach, is assessed following liquid-liquid extraction (LLE) and analysis by gas chromatography-mass selective detection (GC-MSD). The remaining soil residue is then extracted using pressurised fluid extraction (PFE) followed by GC-MSD analysis to assess the residual fraction. The residual fraction is monitored to determine the unavailable fraction i.e. not available for absorption in the gastrointestinal tract of humans. The procedure was applied to four soil samples i.e. an aged, spiked soil and three certified reference materials (CRMs) contaminated with POPs. Recoveries of pesticides (lindane, endosulfan I, endrin, DDE, DDD and endosulfan II), phenols (cresol, TCP and PCP), and base neutral compounds (hexachloroethane, acenaphthene, dibenzofuran, fluorene and hexachlorobenzene) from aged, spiked soil following extraction with gastric fluid ranged from 0.8 to 8.3% while following intestinal extraction ranged from 5.5 to 13.5%, irrespective of POP. Recoveries of pesticides (lindane, endosulfan I, endrin, DDE, DDD and endosulfan II) from CRM 805-050 following extraction with gastric fluid were below the limit of detection while following intestinal extraction ranged from 5.3 to 12.8%. Recoveries of phenols (cresol, TCP and PCP) from CRM 401-225 following extraction with gastric fluid ranged from 1.6 to 2.0% while following intestinal extraction ranged from 4.1 to 5.4%. Recoveries of base neutral acid analytes (hexachloroethane, acenaphthene, dibenzofuran, fluorene and hexachlorobenzene) from CRM 107-100 following extraction with gastric fluid ranged from 1.4 to 4.0% while following intestinal extraction ranged from 6.6 to 12.7%. It has been found that the majority of POPs present i.e. >75%, would be excreted if consumed and not be absorbed in the gastrointestinal tract of humans.

Amylases↗

The distribution of organochlorine pesticides in marine samples along the Indian Ocean coast of Kenya.

The concentrations of organochlorine residues of lindane, aldrin, alpha-endosulfan, dieldrin, endrin, p,p'-DDE, p,p'-DDD and p,p'-DDT in samples of seawater, sediment, fish and seaweed from different locations along the coast of Kenya are discussed in relation to the geographical location of the sampling sites and potential sources of residue over a period of two years. All sediment samples were found to contain very low levels of organic carbon except those sampled from Sabaki River that had high (4.7%) organic carbon due to greater primary activity. Most of the pesticides residues (112 samples analysed in 1997 and 258 analysed in 1998/99) were detected in fish, water, sediments and seaweed. The concentration of some residues was higher during the wet season than the dry season in 1997, but no marked seasonal variation was observed in 1998/99. Lindane, aldrin, p,p'-DDT and p,p'-DDE were the most frequently observed residues in all samples while alpha-endosulfan, dieldrin, p,p'-DDD and endrin were either present low concentrations or absent in most samples. Water samples had the lowest concentrations of residues (range 0.503 - 9.025 ng g(-1)). Sediments had the second highest levels of pesticides residues with a range of 0.584 - 59.00 ng g(-1) while fish lipid content had the highest levels of residues in 1989/99 with p,p'-DDT concentration of 1011 ng g(-1) and 418 ng g(-1) p,p'-DDD in Siganus rivulatus.

Animals↗

Monitoring of organochlorine pesticide residues in pikeperch, Stizostedion lucioperca L. in Beysehir Lake (Central Anatolia).

Fishes in Beysehir Lake were analysed to determine organochlorine pesticide residues. The more frequently detected compounds are DDT complex (DDT, DDD, DDE and isomers), total HCH complex (alpha-HCH, beta-HCH and gamma-HCH or lindane), aldrin, dieldrin, endrin and heptachlorine. Eighty five percent of the fish samples were found to be contaminated. While 75% of the total samples were contaminated by one or more HCH isomers, 63% of the organochlorinated pesticide is DDT and its metabolites. Aldrin, dieldrin and endrin are minor pesticides in samples. Heptachlorine was found in only one sample. Despite their presence high concentrations are sporadic, the mean values being less than FAO/WHO maximum recommended limits.

Animals↗

Effects of insecticides on GABA-induced chloride influx into rat brain microsacs.

The actions of different insecticides known to affect binding of ligands to gamma-aminobutyric acid (GABA) receptors were studied on the function of GABAA receptors in rat brain as assayed by GABA-induced 36Cl- influx into membrane microsacs. This flux was inhibited by the competitive antagonist bicuculline and the noncompetitive antagonist t-butylbicyclophosphorothionate, and the GABA effect was potentiated by the tranquilizer flunitrazepam and the depressant pentobarbital, as expected for effects on a GABAA receptor. The GABA-induced 36Cl- flux was inhibited by several cyclodienes and gamma-hexachlorocyclohexane (gamma-BHC) with the following order of decreasing potency: endosulfan I greater than endrin greater than endosulfan II greater than dieldrin greater than heptachlor epoxide greater than gamma-BHC greater than heptachlor. The noninsecticidal beta-BHC had no effect, while the IC 50 values for gamma-BHC and endrin were 1 and 0.2 microM, respectively. The four pyrethroids tested also inhibited the GABA-induced 36Cl- flux with the following decreasing potencies: 1R,cis,alpha S-cypermethrin greater than 1R,trans, alpha S-cypermethrin greater than fluvalinate greater than allethrin. Avermectin B1a was the only insecticide tested that, in the absence of GABA, stimulated 36Cl- flux in a dose-dependent manner, and this flux was inhibited by bicuculline. The stereospecific inhibition of the GABA-induced 36Cl- influx by the cyclodienes and gamma-BHC supports previously published data on their binding to mammalian brain GABAA receptor and suggests that these insecticides inhibit this receptor's function. It is also suggested that type II pyrethroids are potent inhibitors of the same receptor. However, avermectin B1a appears to act as a partial agonist of GABAA receptors.

Animals↗

Effect of selected insecticides on rat brain synaptosomal adenylate cyclase and phosphodiesterase.

Previous reports from our laboratory and others clearly indicated that organochlorine insecticides such as chlordecone and DDT are potent inhibitors of ATPases involved in active ion transport. The present studies were initiated to study the effect of plictran, chlordecone, toxaphene, aldrin, dieldrin, endrin, isodrin, and telodrin on enzymes involved in cyclic AMP metabolism. Rat brain synaptosomes were prepared by Ficoll-sucrose gradient centrifugation method. Adenylate cyclase activity, which is involved in anabolism of cAMP, was determined using the radioactive method by measuring [32P]cAMP formed during hydrolysis of [32P]ATP. Phosphodiesterase activity, which is involved in the catabolism of cAMP, was estimated by measuring [3H]adenosine formed using [3H]cAMP as a substrate. Synaptosomal adenylate cyclase activity was inhibited significantly by plictran with an IC50 of 25 microM, and a maximum inhibition of 30% was observed with 50 microM chlordecone. Toxaphene, aldrin, dieldrin, endrin, isodrin, and telodrin did not affect the adenylate cyclase activity. Similarly, none of the insecticides studied inhibit the activity levels of synaptosomal phosphodiesterase. The significant inhibition of adenylate cyclase observed with plictran might be due to the tin component, since several heavy metals affect cAMP metabolism. The lack of inhibition of adenylate cyclase and phosphodiesterase with other compounds tested clearly supports our postulation that these organochlorine insecticides exert their neurotoxic action by the selective inhibition of ATPases in synaptosomes.

3',5'-Cyclic-AMP Phosphodiesterases↗

Mortality of workers employed at organochlorine pesticide manufacturing plants--an update.

A previous mortality study among four organochlorine pesticide manufacturers was updated through 1987. The organochlorine pesticides included chlordane; heptachlor and endrin; aldrin, dieldrin and endrin; and dichlorodiphenyltrichloroethane. The mortality for all causes and all malignant neoplasms at each of the plants was lower than expected. There was a statistically significant increase in liver and biliary tract cancer among workers at plant 3 (5 observed, standardized mortality ratio 393, 95% confidence interval 1.27-9.20). These results are somewhat consistent with experimental animal findings showing benign and malignant tumors of the liver after exposure to aldrin and dieldrin. However, the deaths were due to a mixture of intra- and extra-hepatic tumors, and the dose-response analysis was limited because of the small number of deaths and lack of exposure data. Additional study of this group should include continued follow-up of the total cohort and a case-referent analysis of the deaths from liver and biliary tract cancer.

Bile Duct Neoplasms↗

Dietary intake and residues of organochlorine pesticides in foods from Hsinchu, Taiwan.

The levels of contamination with various organochlorine pesticides (such as total HCH, heptachlor, heptachlor epoxide, aldrin, dieldrin, endrin, endosulfan, and total DDT) of different foods from 3 traditional markets were determined to estimate Taiwanese daily intake of organochlorine pesticides. Of the 18 organochlorine pesticides investigated, alpha-HCH, beta-HCH, lindane, delta-HCH, heptachlor, heptachlor epoxide, dieldrin, endrin, alpha-endosulfan, p,p'-DDE, and p,p'-DDT were detected at concentrations ranging from 0.26 to 10.2 ng/g wet weight. Contamination with organochlorine pesticides followed the order heptachlor > dieldrin > alpha-endosulfan > HCH isomers > heptachlor epoxide > DDT. Frequencies of detection of organochlorine pesticide residues ranged from 2.0 to 52.3%. alpha-Endosulfan was the most frequently detected organochlorine pesticide in the foods analyzed, followed by heptachlor epoxide (47.6%) and alpha-HCH (38.9%). Estimated daily intakes (EDIs) of organochlorine pesticides from foods were 1.137 micrograms for total HCH, 2.147 micrograms for heptachlor, 0.702 microgram for heptachlor epoxide, 0.624 microgram for endosulfan, 0.098 microgram for cyclodiene, and 0.541 microgram for total DDT. These EDIs were only 0.075% of the acceptable daily intake (ADI) for lindane, 47.5% of ADI for heptachlor and heptachlor epoxide, 0.045% of ADI for total DDT, and 1.01% of ADI for aldrin and dieldrin. Therefore, consumption of the foods analyzed does not pose a risk to consumer health.

Chromatography, Gas↗

[The contamination of white-tailed sea eagles with organochlorines in Poland].

The residues of PCBs, DDTs, HCHs, HCBz, PCBz, CHLs, aldrin, dieldrin, endrin, isodrin, endosulfan 1, endosulfan 2, mirex, TCPM-H and TCPM-OH were determined in breast muscles and an egg of white-tailed sea eagles collected in Poland in 1991-1995. The method of measurement was capillary gas chromatography and low resolution mass spectrometry (HRGC/LRMS) after a non-destructive extraction, clean-up and fractionation of the sample. Only aldrin, endrin, endosulfan 1 and endosulfan 2 were absent in birds and egg examined. Some of the adult white-tailed sea eagles collected dead from the coastal area of the Baltic Sea still remain relatively high contaminated with organochlorines, and the concentrations of PCBs and DDTs in those birds ranged between 2300-2600 and 490-2000 micrograms/g lipids, respectively. In dead egg concentration of PCBs was 390 micrograms/g lipids (25 micrograms/g wet weight), while of DDTs 270 micrograms/g lipids (18 micrograms/g w.w.).

Animals↗

Pesticide residue concentrations in soils of five United States cities, 1971--urban soils monitoring program.

Soil samples from five metropolitan areas including Baltimore, Maryland; Gadsden, Alabama; Hartford, Connecticut; Macon, Georgia; and Newport News, Virginia were analyzed for elemental arsenic, organochlorine pesticides, and polychlorinated biphenyls (PCBs). A representative number of samples were analyzed for organophosphorus pesticides, but none was detected. All areas exhibited heavy soil concentrations of organochlorine pesticides including sigma DDT, aldrin, dieldrin, photodieldrin, chlordane, heptachlor, heptachlor epoxide, endrin, endrin ketone, and endosulfan sulfate. PCBs were detected in three of the five metropolitan areas. Within the metropolitan areas, samples from the urban, or core city, locations generally had higher pesticide concentrations than did samples from suburban locations. Finally, pesticide residue concentrations were generally higher in soils of metropolitan areas than in nearby agricultural soils.

Arsenic↗

Organochlorine insecticide residues in field soils of the Kitakyushu district--Japan 1970-74.

Residues of organochlorine insecticides were monitored in field soils of the Kitakyushu District, Japan, from 1970 to 1974, before and after the insecticides were banned from agricultural fields. The arithmetic mean (AM) and geometric mean (GM) of BHC reached maximum levels in 1970 and 1971, then decreased rapidly during 1972 and 1974. Among BHC isomers, beta-BHC had highest mean levels and was therefore thought to be the most persistent of the isomers in field soils. Residues of aldrin, dieldrin, and endrin peaked in 1970 and/or 1971, and then decreased yearly. The percentage of sites which had aldrin contamination have decreased; those with dieldrin contamination have increased. Mean values of p,p'-DDE, p,p'-DDT, and sigmaDDT declined more slowly than did BHC and cyclodienes. Values of DDT and its related compounds were higher than were those of BHC, aldrin, dieldrin, and endrin. The residues of p,p'-DDE were most frequently detected of the DDT compounds.

Chromatography, Gas↗

Extraction and gas chromatographic screening of 14 chlorinated pesticides in crayfish (Procambarus clarkii) hepatopancreas.

A multiresidue isolation technique using matrix solid-phase dispersion (MSPD) and gas chromatography/electron capture detection is applied to crayfish (Procambarus clarkii) hepatopancreas for the extraction and determination of 14 chlorinated pesticides (alpha-BHC, beta-BHC, lindane, heptachlor, aldrin, heptachlor epoxide, p,p'-DDE, dieldrin, endrin, 4,4'-DDD, endrin aldehyde, p,p'-DDT, endosulfan sulfate, and methoxychlor). Pureed crayfish hepatopancreata (0.5 g aliquot) are fortified with the 14 pesticides and with delta-BHC as an internal standard before blending with 2 g C18 (octadecylsilyl)-derivatized silica. The C18-hepatopancreas matrix blend and 2 g activated Florisil comprise an extraction column from which the pesticides are eluted by adding 8 mL acetonitrile. Two microliters of the eluate is directly analyzed by gas chromatography with electron capture detection. Unfortified blank controls are treated similarly. The eluate contained all the pesticide analytes and was free of interfering coextractants at most fortification levels. Correlation coefficients for the 14 extracted pesticide standard curves (linear regression analysis) ranged from 0.9685 to 0.9985. Average relative percent recoveries (recoveries for all pesticides ranged from 55 +/- 10.4% to 118 +/- 45.2%, n = 15 for each pesticide) over the range of concentrations examined, interassay variability (7.1 +/- 5.7% to 16.0 +/- 5.6%, n = 15 for each pesticide), and intra-assay variability (0.0-26.2%, n = 5 for each pesticide) indicated that the MSPD methodology allowed for the successful extraction and determination of the 14 chlorinated pesticides at 125-2000 ng/g levels in crayfish hepatopancreas.

Animals↗

Matrix solid-phase dispersion extraction and gas chromatographic screening of 14 chlorinated pesticides in oysters (Crassostrea virginica).

A multiresidue isolation technique known as matrix solid-phase dispersion (MSPD) is presented for the extraction and subsequent gas chromatographic/electron capture detection (GC/ECD) determination of 14 chlorinated pesticides (alpha-BHC, beta-BHC, lindane, heptachlor, aldrin, heptachlor epoxide, p,p'-DDE, dieldrin, endrin, 4,4'-DDD, endrin aldehyde, p,p'-DDT, endosulfan sulfate, and methoxychlor) from oysters (Crassostrea virginica). Pureed whole oysters (0.5 g aliquots) are fortified with the 14 pesticides and delta-BHC, as an internal standard, and blended with 2 g C18 (octadecylsilyl)-derivatized silica. Pesticides are eluted from an extraction column composed of C18/oyster matrix blend and 2 g activated Florisil by addition of 8 mL acetonitrile-methanol (90 + 10). Then, 2 microL of the eluate is analyzed by GC/ECD. Unfortified blank controls are treated similarly. The eluate contained all the pesticide analytes and was free of interfering coextractants. Correlation coefficients for the standard curves of the 14 extracted pesticides (linear regression analysis) ranged from 0.9849 to 0.9980. Average relative percent recoveries over the range of concentrations examined (66 +/- 12.7% to 84 +/- 25.3%, n = 25 for each pesticide), interassay variability (13.6 +/- 8.8% to 30.2 +/- 9.1%, n = 25 for each pesticide), and intra-assay variability (5.8-11.8%, n = 5 for each pesticide) indicated that the MSPD methodology successfully extracted and determined the 14 chlorinated pesticides in oyster at levels of 31.3-500 ng/g.

Animals↗

Monitoring of pesticide residues in human milk, soil, water, and food samples collected from Kafr El-Zayat Governorate.

Pesticide residues in human milk and environmental samples from Kafr El-Zayat Governorate in Egypt were analyzed. This governorate is located near one of the biggest pesticide factories in Egypt. Organochlorine and organophosphorus pesticides were monitored, including those that have been prohibited from use in Egypt. Human milk samples (31 samples) from Kafr El-Zayat were compared with 11 samples collected from Cairo. Data were compared with results from studies performed in 1987 and 1990. The present study showed that aldrin and dieldrin, heptachlor and heptachlor epoxide, and endrin residues have been eliminated from human milk. Estimated daily intakes (EDIs) of DDT complex and gamma-HCH by breast-fed infants in Kafr El-Zayat were 85.96 and 3.1% of the respective acceptable daily intakes (ADIs). beta-HCH residues showed an increasing pattern, especially in human milk samples from Cairo. DDT complex and HCH isomers in orange, spinach, lettuce, potatoes, and clover samples ranged from undetectable to very low concentrations. Higher levels of DDT and HCH were detected, but aldrin, dieldrin, endrin, and the heptachlors were not detected in food of animal origin. Residues in fish samples were below maximum residue limits established by some developed countries. Those in animal milk samples approached the extraneous residue limits of the Codex Committee on Pesticide Residues. HCH residues in soil were negligible, but DDT residues in soil were somewhat higher. Among water samples, groundwater samples had the highest residues of HCHs and DDTs, followed by Nile River water and then tap water. However, the organochlorine pesticide residues were found at concentrations below the maximum allowable limits set by the World Health Organization for drinking water. Among 12 organophosphorus pesticides monitored as parent compounds, dimethoate, malathion, methamidophos, and chlorpyrifos residues were detected in low concentrations in soil samples from a pesticide factory. No organophosphorus pesticide residues were found in plant samples, except for very low residues of dimethoate in an orange sample. Water samples were devoid of organophosphorus residues as parent compounds.

Animals↗

Cytotoxicity of hexachlorocyclohexane isomers and cyclodienes in primary cultures of cerebellar granule cells.

The cytotoxicity of the neurotoxic hexachlorocyclohexane (HCH) isomers alpha, beta, gamma (lindane) and delta and of the cyclodienes aldrin, endrin and alpha-endosulfan were studied in primary neuronal cultures of cerebellar granule cells. Disruption of cell membrane integrity, as indicative of cytotoxicity, was measured by propidium iodide staining. Additionally, the effects of these xenobiotic agents on three endpoints of the cellular status, concentration of intracellular-free calcium, intracellular oxygen-free radical formation and mitochondrial transmembrane potential were analyzed in parallel cultures to understand better the mechanisms of their neurocytotoxic action. To measure these parameters, the probes of the acetoxymethyl ester of fluo-3, 2',7'-dichlorofluorescin diacetate and rhodamine 123, respectively, were used. The order of cytotoxic potency of the HCH-isomers and the cyclodienes (delta-HCH > gamma-HCH > alpha-HCH approximately equal to aldrin approximately equal to alpha-endosulfan >> endrin approximately equal to beta-HCH) was very different from their in vivo LD50 order. delta-, gamma- and alpha-HCH increased the concentration of intracellular-free calcium, whereas delta- and gamma-HCH and alpha-endosulfan increased mitochondrial transmembrane potential, but none of the compounds generated oxygen-free radicals. The inhibition of delta- and gamma-HCH effects by several specific pharmacological agents suggests that delta-HCH causes its cytotoxic effects in part through intracellular Ca++ mobilization from intracellular pools sensitive to neomycin, whereas gamma-HCH acts through Ca++ influx and dantrolene-sensitive intracellular Ca++ mobilization. The use of selected endpoints of the cellular status proved to be a valuable tool to study the mechanisms of cytotoxicity.

Animals↗