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PubMed2001

Pesticides and nitrate in groundwater and rainwater in the Province of Limburg in The Netherlands.

The purpose of this study was to investigate the occurrence of high levels of pesticides in groundwater and rainwater in The Province of Limburg in The Netherlands. In groundwater samples in particular the presence of triazines--atrazine, simazine and propazine--was observed; besides these pesticides, dieldrin has also been observed. Atrazine and simazine were found to exceed the groundwater standard of 100 ng L(-1). In the rainwater samples, the presence of 13 of 23 different analyzed pesticides was observed. A number of pesticides were found in high concentrations; e.g. atrazine (>200 ng L(-1)). Two pesticides detected in rainwater (beta+gamma-HCH and atrazine) were found to exceed the groundwater standard. Seven pesticides in rainwater were found to exceed the target value and three pesticides the maximum tolerable risk value (DDT, heptachlor and heptachlorepoxide A), which are used as ecotoxicological standards in The Netherlands. Nitrate in 15 of 16 analyzed natural springs was found to exceed the guideline value for nitrate in drinking water of 50 mg L(-1), up to levels of about 200 mg L(-1). Nitrate concentrations in rainwater samples were observed up to 4.5 mg L(-1). A risk analysis of exposure to high pesticide levels in groundwater or rainwater has been performed using the model HESP. For atrazine levels due to deposition of rainwater in two different locations, exceedance of the T.D.I. level of 0.5 microg kg(-1) day(-1) based on WHO criteria was observed for children using both an urban and a rural scenario and use of groundwater as drinking water.

Environmental Monitoring↗
PubMed2001

Contaminant profiles of two species of shorebirds foraging together at two neighboring sites in South San Francisco Bay, California.

The San Francisco Bay estuary is used by over one million shorebirds during spring migration and is home to several hundred thousand during the winter. Most shorebird use occurs in the southern reach of the estuary (South Bay). The reduced water circulation and discharge from industrial sources in the South Bay are responsible for the highest levels of some trace elements in the estuary. Wintering shorebirds have been found to have strong site fidelity to areas as small as a few kilometers in the South Bay, which may increase their exposure to contaminants near local point sources. In addition, different shorebird species foraging at the same site have been shown to have different contaminant burdens. Thus, our objectives were to test whether contaminant burdens differed by species, or whether contaminant burdens differed in shorebirds collected at adjacent sites. We examined the contaminant profiles of two species of shorebirds, long-billed dowitchers (Limnodromus scolopaceus) and western sandpipers (Calidris mauri) that forage together at two sites, Hayward and Newark, separated by 8 km in the South Bay. We used multivariate analysis of variance tests to compare the composition of 14 elemental analytes in their liver tissues and estimated their molar ratios of Hg and Se. Composite samples were used for contaminant analyses because of the small body size of the shorebirds. Seven elemental analytes (Ag, Ba, Be, Cr, Ni, Pb, V) were below detection limits in a majority of the samples so statistical analyses were precluded. In the measurable analytes (As, Cd, Cu, Hg, Mn, Se, Zn), we found no significant intra-site differences of contaminant profiles for the two species. We pooled the samples to examine inter-site differences and found significant differences in contaminant profiles between shorebirds at the neighboring sites (P = 0.03). Shorebirds at Newark had higher (P < 0.05) concentrations of As, Cd, and Se than those at Hayward. Dowitchers at Newark had concentrations of Hg and Se which were highly correlated (P < 0.003) in a mean molar ratio of 1:19, similar to that reported in other birds. In the larger dowitcher species, we also examined exposure to 20 organochlorine compounds. Organic analyses showed that the dowitchers had been exposed to DDE, PCBs, dieldrin and trans-nonachlor, but with no significant differences in concentrations between Hayward and Newark (P > 0.05).

Animals↗
PubMedDate not supplied

An assessment of DDT and other chlorinated compounds and the reproductive success of American robins (Turdus migratonrius) breeding in fruit orchards.

Although DDT was banned in the 1970s, American robins (Turdus migratorius) breeding in fruit orchards of the Okanagan Valley, British Columbia, continue to be contaminated with DDT and its metabolites. The objectives of our study were (1) to assess organochlorine (OC) contamination in robins breeding in Okanagan orchards (1993-1995, 1997-1998) and (2) to determine if exposure affected reproductive success when compared to robins from non-orchard habitat (lower mainland, British Columbia). Robins in orchards had total DDT egg residues of 48.64 mg/kg (geometric mean; n = 92) while those in non-orchard habitat had 1.10 mg/kg (geometric mean; n = 26), wet weight. The probability of nest survival during the incubation period was 96.7% (confidence interval: 95.7-97.5%; n = 165) in orchard habitat and 96.7% (confidence interval: 94.6-98.1%; n = 28) in non-orchard habitat. During the nestling period the probability of nest survival was 98.2% (confidence interval: 97.2-98.9%; n = 123) in orchard habitat and 96.2% (confidence interval: 92.8-98.0%; n = 34) in non-orchard habitat. Clutch (p < 0.0001) and brood size (p = 0.0133) were larger in orchards (n = 150 and n = 93, respectively) compared to non-orchard nests (n = 42 and n = 23, respectively) with no difference in fledge rate. DDE (r2 = 0.11, p = 0.0030, n = 68) and dieldrin (r2 = 0.29, p < 0.0001, n = 68) were negatively correlated with fledge rate in robin eggs collected from orchard habitat, however, low r2 values signify minimal biological significance. Although American robins nesting in Okanagan orchards are exposed to high OC levels, reproductive success does not appear to be negatively impacted.

Agriculture↗
PubMedDate not supplied

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↗
PubMed2000

Single channel analysis of the blocking actions of BIDN and fipronil on a Drosophila melanogaster GABA receptor (RDL) stably expressed in a Drosophila cell line.

Single channel recordings were obtained from a Drosophila S2 cell line stably expressing the wild-type RDL(ac) Drosophila melanogaster homomer-forming ionotropic GABA receptor subunit, a product of the resistance to dieldrin gene, RDL: GABA (50 microM) was applied by pressure ejection to outside-out patches from S2-RDL cells at a holding potential of -60 mV. The resulting inward current was completely blocked by 100 microM picrotoxin (PTX). The unitary current-voltage relationship was linear at negative potentials but showed slight inward rectification at potentials more positive than 0 mV. The reversal potential of the current (E(GABA)=-1.4 mV) was close to the calculated chloride equilibrium potential. The single channel conductance elicited by GABA was 36 pS. A 71 pS conductance channel was also observed when the duration of the pulse, used to eject GABA, was longer than 80 ms. The mean open time distribution of the unitary events was fitted best by two exponential functions suggesting two open channel states. When either 1 microM fipronil or 1 microM BIDN was present in the external saline, the GABA-gated channels were completely blocked. When BIDN or fipronil was applied at a concentration close to the IC(50) value for suppression of open probability (281 nM, BIDN; 240 nM, fipronil), the duration of channel openings was shortened. In addition, the blocking action of BIDN resulted in the appearance of a novel channel conductance (17 pS). The effects of co-application of BIDN and fipronil were examined. Co-application of BIDN (300 nM) with various concentrations (100-1000 nM) of fipronil resulted in an additional BIDN-induced dose-dependent reduction of the maximum P(o) value. Thus both BIDN and fipronil shorten the duration of wild-type RDL(ac) GABA receptor channel openings but appear to act at distinct sites.

Animals↗
PubMed2004

Drosophila melanogaster GRD and LCCH3 subunits form heteromultimeric GABA-gated cation channels.

In addition to its action as a fast inhibitory neurotransmitter, gamma-aminobutyric acid (GABA) is thought to mediate excitatory action by activating cation currents in some cell types in invertebrates. However, to date no GABA receptor capable of mediating such action has been identified at the molecular level in insects. Using a systematic expression screening approach, we found that the Drosophila ligand-gated ion channel subunits GRD and LCCH3 combine to form cation-selective GABA-gated ion channels when coexpressed in Xenopus laevis oocytes. The heteromultimeric receptor is activated by GABA (EC50=4.5 microm), muscimol (EC50=4.8 microm) and trans-4-aminocrotonic acid (EC50=104.5 microm), and partially by cis-4-aminocrotonic acid (EC50=106.3 microm). Picrotoxin effectively blocked the GABA-gated channel (IC50=0.25 microm), but bicuculline, TPMTA, dieldrin and lindane did not. The benzodiazepines flunitrazepam and diazepam did not potentiate the GABA-evoked current. Our data suggest that heteromultimeric channels composed of GRD and LCCH3 subunits form GABA-gated cation channels in insects.

Animals↗
PubMed2006

Pesticides and their metabolites in the homes and urine of farmworker children living in the Salinas Valley, CA.

In support of planning efforts for the National Children's Study, we conducted a study to test field methods for characterizing pesticide exposures to 20 farmworker children aged 5-27 months old living in the Salinas Valley of Monterey County, California. We tested methods for collecting house dust, indoor and outdoor air, dislodgeable residues from surfaces and toys, residues on clothing (sock and union suits), food, as well as spot and overnight diaper urine samples. We measured 29 common agricultural and home use pesticides in multiple exposure media samples. A subset of organophosphorus (OP), organochlorine (OC) and pyrethroid pesticides were measured in food. We also analyzed urine samples for OP pesticide metabolites. Finally, we administered four field-based exposure assessment instruments: a questionnaire; food diary; home inspection; and a self-administered child activity timeline. Pesticides were detected more frequently in house dust, surface wipes, and clothing than other media, with chlorpyrifos, diazinon, chlorthal-dimethyl, and cis- and trans-permethrin detected in 90% to 100% of samples. Levels of four of these five pesticides were positively correlated among the house dust, sock, and union suit samples (Spearman's rho=0.18-0.76). Pesticide loading on socks and union suits was higher for the group of 10 toddlers compared to the 10 younger crawling children. Several OP pesticides, as well as 4,4'-DDE, atrazine, and dieldrin were detected in the food samples. The child activity timeline, a novel, low-literacy instrument based on pictures, was successfully used by our participants. Future uses of these data include the development of pesticide exposure models and risk assessment.

Agriculture↗
PubMed1992

Comparison of solvent extraction and solid-phase extraction for the determination of organochlorine pesticide residues in water.

Solid-phase extraction (SPE) of organochlorine pesticide residues from environmental water samples was evaluated using octadecyl (C18)-bonded porous silica. The efficiency of SPE of these pesticide residues from reagent water samples at 1-5 micrograms dm-3 levels was compared with those obtained by solvent extraction with hexane and Freon TF (trichlorotrifluoroethane). Average recoveries exceeding 80% for these organochlorine pesticides were obtained via the SPE method using small cartridges containing 100 mg of 40 microns C18-bonded porous silica. The average recovery by solvent extraction with hexane and Freon TF exceeded 90% in both instances. It was concluded that the recoveries and precision for the SPE of organochlorine pesticides were poorer than those for the solvent extraction method. Organochlorine pesticide residue levels in environmental water samples from two major rivers flowing through predominantly rice-growing areas were monitored by gas chromatography using the solvent extraction method with hexane. Exceptionally high levels of organochlorine pesticide residues such as BHC, DDT, heptachlor, endosulfan and dieldrin were found in these water samples.

Chromatography, Gas↗
PubMed1992

Report of two co-operative trials of a gel permeation chromatographic method for the isolation of pesticide residues from oils and fats. Committee for Analytical Methods for Residues of Pesticides in Foodstuffs of the Ministry of Agriculture, Fisheries and Food.

A gel permeation chromatographic (GPC) method for the determination of pesticide residues in fats and oils was subjected to two co-operative trials. Results for organochlorine pesticides (beta-HCH, gamma-HCH, dieldrin, p,p'-DDE and heptachlor) were compared with those obtained using an alumina column clean-up method. No significant differences in the mean values were found between the two techniques using the t-test (5% significance level). Horrat values demonstrated acceptable inter- and intralaboratory precisions for both clean-up techniques. Two organophosphorus pesticides (diazinon and propetamphos) and the synthetic pyrethroid deltamethrin were also determined using the GPC method. However, these compounds were not recoverable using the alumina column method, so no comparisons between the two methods were possible.

Chromatography, Gel↗
PubMed1998

Lack of nucleotide variability in a beetle pest with extreme inbreeding.

The coffee berry borer beetle Hypothenemus hampei (Ferrari) (Curculionidae: Scolytinae) is the major insect pest of coffee and has spread to most of the coffee-growing countries of the world. This beetle also displays an unusual life cycle, with regular sibling mating. This regular inbreeding and the population bottlenecks occurring on colonization of new regions should lead to low levels of genetic diversity. We were therefore interested in determining the level of nucleotide variation in nuclear and mitochondrial genomes of this beetle worldwide. Here we show that two nuclear loci (Resistance to dieldrin and ITS2) are completely invariant, whereas some variability is maintained at a mitochondrial locus (COI), probably corresponding to a higher mutation rate in the mitochondrial genome. Phylogenetic analysis of the mitochondrial data shows only two clades of beetle haplotypes outside of Kenya, the proposed origin of the species. These data confirm that inbreeding greatly reduces nucleotide variation and suggest the recent global spread of only two inbreeding lines of this bark beetle.

Animals↗
PubMed2003

Molecular evidence for a kdr-like pyrethroid resistance mechanism in the malaria vector mosquito Anopheles stephensi.

The mosquito Anopheles stephensi Liston (Diptera: Culicidae) is the urban vector of malaria in several countries of the Middle East and Indian subcontinent. Extensive use of residual insecticide spraying for malaria vector control has selected An. stephensi resistance to DDT, dieldrin, malathion and other organophosphates throughout much of its range and to pyrethroids in the Middle East. Metabolic resistance mechanisms and insensitivity to pyrethroids, so-called knockdown resistance (kdr), have previously been reported in An. stephensi. Here we provide molecular data supporting the hypothesis that a kdr-like pyrethroid-resistance mechanism is present in An. stephensi. We found that larvae of a pyrethroid-selected strain from Dubai (DUB-R) were 182-fold resistant to permethin, compared with a standard susceptible strain of An. stephensi. Activities of some enzymes likely to confer pyrethroid-resistance (i.e. esterases, monooxygenases and glutathione S-transferases) were significantly higher in the permethrin-resistant than in the susceptible strain, but the use of synergists--piperonyl butoxide (PBO) to inhibit monooxygenases and/or tribufos (DEF) to inhibit esterases--did not fully prevent resistance in larvae (permethrin LC50 reduced by only 51-68%), indicating the involvement of another mechanism. From both strains of An. stephensi, we obtained a 237-bp fragment of genomic DNA encoding segment 6 of domain II of the para type voltage-gated sodium channel, i.e. the putative kdr locus. By sequencing this 237 bp fragment, we identified one point mutation difference involving a single A-T base change encoding a leucine to phenylalanine amino acid substitution in the pyrethroid-resistant strain. This mutation appears to be homologous with those detected in An. gambiae and other insects with kdr-like resistance. A diagnostic polymerase chain reaction assay using nested primers was therefore designed to detect this mechanism in An. stephensi.

Amino Acid Sequence↗
PubMed2001

Dopaminergic cell death induced by MPP(+), oxidant and specific neurotoxicants shares the common molecular mechanism.

Recent etiological study in twins (Tanner et al. 1999) strongly suggests that environmental factors play an important role in typical, non-familial Parkinson's disease (PD), beginning after age 50. Epidemiological risk factor analyses of typical PD cases have identified several neurotoxicants, including MPP(+) (the active metabolite of MPTP), paraquat, dieldrin, manganese and salsolinol. Here, we tested the hypothesis that these neurotoxic agents might induce cell death in our nigral dopaminergic cell line, SN4741 (Son et al. 1999) through a common molecular mechanism. Our initial experiments revealed that treatment with both MPP(+) and the other PD-related neurotoxicants induced apoptotic cell death in SN4741 cells, following initial increases of H(2)O(2)-related ROS activity and subsequent activation of JNK1/2 MAP kinases. Moreover, we have demonstrated that during dopaminergic cell death cascades, MPP(+), the neurotoxicants and an oxidant, H(2)O(2) equally induce the ROS-dependent events. Remarkably, the oxidant treatment alone induced similar sequential molecular events: ROS increase, activation of JNK MAP kinases, activation of the PITSLRE kinase, p110, by both Caspase-1 and Caspase-3-like activities and apoptotic cell death. Pharmacological intervention using the combination of the antioxidant Trolox and a pan-caspase inhibitor Boc-(Asp)-fmk (BAF) exerted significant neuroprotection against ROS-induced dopaminergic cell death. Finally, the high throughput cDNA microarray screening using the current model identified downstream response genes, such as heme oxygenase-1, a constituent of Lewy bodies, that can be the useful biomarkers to monitor the pathological conditions of dopaminergic neurons under neurotoxic insult.

1-Methyl-4-phenylpyridinium↗
PubMedDate not supplied

Organochlorine pesticide concentrations in perinatal samples from mothers and babies.

Samples were obtained from Dutch mothers and their babies throughout the perinatal period and analyzed by gas-liquid chromatography with electron-capture detection for a range of organochlorine pesticides. Organochlorine concentrations in the blood of breast or bottle-fed babies were not significantly different. Differences in organochlorine concentrations in blood between mothers who had "slimmed" and those who had not were small, but it must be noted that there were few slimming mothers in our sample. Twelve to 21% and 36-61% of the estimated daily intake of dieldrin and DDT, respectively, by mothers may be eliminated by lactation. The placenta restricts the transmission of organochlorine pesticides to the fetus to some extent. The very low concentrations of organochlorine in fetal blood prevented a study of the comparative metabolism in mothers and babies.

Body Weight↗
PubMedDate not supplied

Chlorinated hydrocarbons in human bone marrow of healthy individuals and leukemia patients.

In this pilot study, concentrations of chlorinated hydrocarbons in bone marrow were determined by capillary-column gas chromatography. Bone marrow was obtained from a total of 29 healthy adults and from patients with leukemia or lymphoma. The chlorinated hydrocarbons in adults that occurred in the highest concentrations were dichlorodiphenyltrichloroethane and its derivatives (mean = 129 mg/g DNA). Hexachlorobenzene, the hexachlorohexane isomers, and dieldrin were also found, but in reduced concentrations (i.e., mean concentrations: 49.5 mg/g DNA, 14.9 mg/g DNA, and 5.9 mg/g DNA, respectively). Patients who had leukemia and lymphoma did not have significantly increased concentrations of chlorinated hydrocarbons.

Adult↗
PubMed2000

Toxaphene is antiestrogenic in a human breast-cancer cell assay.

Toxaphene is a complex mixture of chlorinated bornanes, bornenes, and bornadienes and was a heavily used insecticide in the United States until its use was restricted in 1982. There are conflicting reports regarding the potential for toxaphene to induce estrogenic responses in human and nonhuman animals. Due to the public concern over environmental estrogens, the estrogenicity of toxaphene was examined in a human breast-cancer cell assay, the MCF-7 focus assay, which is based on in vitro postconfluent cell proliferation and tissue restructuring. In this assay, 0.1-1 nM 17beta-estradiol (E2) produces maximum postconfluent proliferation and formation of multicellular nodules or foci. Toxaphene was also tested for its ability (1) to bind the estrogen receptor (ER) in a competitive binding assay using recombinant human ERalpha (rhER) and in a whole-cell competitive ER binding assay, and (2) to alter the catabolism of E2 in MCF-7 cell cultures. Results from the MCF-7 focus assay showed: (1) Toxaphene alone was not estrogenic between the concentrations of 0.5 nM and 10 microM, (2) toxaphene in binary combinations with chlordane, dieldrin, or endosulfan (alpha or beta) was not estrogenic, and (3) toxaphene was weakly antiestrogenic (it reduced the number of foci induced by 0.1 nM and 0.01 nM E2). Results from the competitive binding assays showed that (1) toxaphene alone did not bind rhER or ER in MCF-7 cells, and (2) toxaphene in binary combinations with other pesticides did not bind rhER. Results from the growth assay and radiometric analysis of E2 catabolism showed that (1) toxaphene did not alter the growth rate of MCF-7 cell cultures over 13 d, and (2) toxaphene did not alter the catabolism of E2. In conclusion, results from the MCF-7 focus assay demonstrate that toxaphene is weakly antiestrogenic rather than estrogenic.

Binding, Competitive↗
PubMed1999

The interaction of chlorinated alicyclic insecticides with brain GABA(A) receptors in channel catfish (Ictalurus punctatus).

Chlorinated alicyclic insecticides are believed to antagonize the action of the neurotransmitter gamma-aminobutyric acid (GABA) at its receptor in vertebrates. Binding of the specific GABA(A) receptor ligand [35S]-t-butylbicyclophosphorothionate (TBPS) to channel catfish brain P2 membranes suggested a single population of receptors with a Kd (56.6+/-2.6 nM) and Bmax (2435+/-276 fmol/mg protein) that are similar to published values for other fish species. The competition of several chlorinated compounds for TBPS binding was investigated. The most potent inhibitors of TBPS binding were 12-ketoendrin, photoheptachlor epoxide, photoheptachlor, telodrin, and endrin, respectively, with IC50s of 20-90 nM. Photooxychlordane, photo alpha-chlordane, and oxychlordane were intermediate in potency (122-219 nM), as were isodrin, dihydroisodrin, heptachlor epoxide, and alpha-chlordane, which were similar in potency (311-397 nM). Dieldrin, lindane, and dihydroaldrin were much less potent (592-1103 nM). Heptachlor, aldrin, and gamma-chlordane were weak inhibitors of TBPS binding (2073-2738 nM). Chlordene and chlordecone had the lowest potency of all compounds studied (10,201-21,178 nM) with the exception of mirex, which did not inhibit binding at a concentration of 50 microM. There is a good correlation between binding potency and the available toxicity data for several of these compounds in channel catfish. There is also a good correlation between the inhibitory potency in channel catfish by these types of compounds with that in rats.

Animals↗
PubMed1999

Prevalence of antinuclear antibodies in a rural population.

Exposure to environmentally and occupationally encountered toxicants can be associated with the development of certain autoimmune diseases and with the induction of antinuclear antibodies (ANA). Some chemicals used in the agricultural industry are known to affect immune function but their roles in the induction of autoimmunity in general, and ANA in particular, have not been reported previously. This study was undertaken to establish the prevalence of ANA in a rural population and to determine environmental and occupational exposures with which they are associated. This cross-sectional study represented one component of an interdisciplinary project (Prairie Ecosystem Study [PECOS], Eco-Research Program, Tri-Council Secretariat of Canada) designed to explore, in a rural population, the roles of environmental exposures as determinants of human health status. Information regarding lifetime, current, and main occupational exposures in the rural-dwelling study population was derived from a self-administered questionnaire. Sera from consenting subjects, collected during the months of February and March 1996, were assayed for ANA by indirect immunofluorescence on HEp-2 cells. The study population comprised 322 adult subjects (mean age 49.3+/-14.7 yr; range 16-87 yr). Statistical analyses adjusted for age and sex revealed that the presence of ANA among the participants was associated with a current agricultural occupation that included oilseed production, hog production, or poultry production. There was a significant association between ANA positivity and a current main farming operation of crop production. There was also an association among individual participants between lifetime exposure to the insecticide class of pesticides and the presence of ANA. In this rural study population, ANA positivity was significantly associated with lifetime exposure specifically to carbamate, organochlorine (including aldrin, chlordane, dieldrin, endrin, heptachlor, and lindane, but excluding DDT and methoxychlor), and pyrethroid insecticides and to phenoxyacetic acid herbicides, including 2,4-D. After adjustment for age, sex, and other insecticide exposures, multivariate analyses indicated that ANA positivity was associated with current oilseed production and with lifetime exposure to pyrethroid insecticides. In a rural population, ANA were associated with production of certain crops and certain animals and exposure to specific pesticides. The data indicate that some occupational exposures related to the agricultural industry are associated with the presence of ANA, a serologic expression of autoimmunity.

Adolescent↗
PubMed1982

On the ecology of the harbour seal Phoca vitulina in the Wadden Sea: population dynamics, residue levels, and management .

The harbour seal population in the Dutch Wadden Sea decreased significantly during the last decades. Calculations based on bounty data revealed that the population decreased from about 2700 in 1950 to about 900 in 1959. Annual aerial surveys--which were carried out since that time--showed a slight increase due to the stop of hunting. However, after 1964 a new decline occurred and since 1974 the population stays at a level of about 450 specimens. During 1974 to 1978 the population dynamics of the population have been studied Frequent aerial surveys provided data on the size of the population. These data have been used in a simulation model and the birth rate and the initial juvenile mortality were calculated. During boat trips an indication of the age composition was obtained by measuring track widths. By comparing these results with similar results from a stable population in Schleswig Holstein it appeared: (1) that juvenile mortality in the first weeks in the Dutch population is higher than that in Schleswig Holstein but the overall mortality of pups in both areas in their first three months of life is of the same order; (2) that pup production in the Dutch population is low compared to the population in Schleswig Holstein; (3) that apparently immigration from elsewhere occurs. To investigate the contribution of environmental pollution to the decline of the Dutch seal population tissues of dead, stranded animals originating from Schleswig Holstein, Denmark and the Netherlands were collected and analyzed for PCBs, o,p'-DDT, p,p'-(DDT, DDE, TDE), dieldrin, aldrin, endrin, endosulfan, alpha, beta, gamma,-HCH, HCB, QCB (pentachlorobenzene), HEPO, total mercury, methyl-mercury, selenium and bromium. Considering epidemiological and experimental data on the effects of PCBs on mammalian reproduction, strong support is obtained for the hypothesis that PCBs are responsible for the decreased reproduction in seals from the Dutch Wadden Sea. if PBCs are responsible for the decrease of the Dutch seal population, measure of all North Sea countries are urgently required because these PCBs may not only be a hazard to seals but also to other animals and even man. Production and use of PCBs should be limited and used PCBs should be collected and destroyed. However, even if an immediate ban on PCB's would be effected, the effects of PCBs because of their persistent character are likely to last many years. For that reason it may be assumed that the seal population in the western Wadden Sea still faces a difficult period in the years to come. In order to lead this population through this difficult period, all possible measures enhancing its continued existence should be taken. Since the seals in the Wadden Sea form one population maximum result may be expected from measures applying to all seals in the Wadden Sea. Thus international cooperation is necessary. The following measures are proposed: Continued interdiction of hunting in order to obtain a maximum number of animals taking part in reproduction. Establishment of seal reserves and, additionally supporting seal nursery stations in order to guarantee a maximum reproductive output. However, it has to be stressed that these measures are not effective if at the same time the main cause of the decrease is not found and brought under control.

Animals↗