Residues In Fat Research Articles

A sensitive and robust analytical method for the determination of enramycin residues in swine tissues using UHPLC-MS/MS.

Enramycin, a common growth promoter utilized in chickens and pigs, is sensitive against Gram-positive bacteria, and the maximum residue limit (MRL) of enramycin set up by is 30 μg/kg. However, the methods have been reported for detecting enramycin have failed to meet the accuracy requirements, with the required limit of quantification being higher than the MRL. To address this issue, we developed a high-sensitive and robust analytical method based on ultrahigh-performance liquid chromatography coupled with mass spectrometry (UHPLC-MS/MS), to determine enramycin residues in swine tissues, including liver, kidney, pork, and fat. The ENV cartridge was selected to cleanup and enrich analytes after being extracted using a mixture of 55% methanol containing 0.2 M hydrochloric acid. With comprehensively validation, this established method was found great linearity of enramycin in each tissue, with a coefficient of variation above 0.99. Satisfactory recoveries from four different spiking levels were acquired (70.99-101.40%) while the relative standard deviations were all below 9%. The limit of quantification of enramycin in the present study is 5 μg/kg in fat and 10 μg/kg in other tissues, meeting the requirements for conducting the corresponding safety evaluation study. This method was demonstrated with excellent specificity, stability, and high sensitivity. To conclude, this novel approach is sufficiently sensitive and robust for the safety evaluation of enramycin in food products.

English

Hemp seed and hemp seed products such as hemp seed cake (HSC) have been shown to increase unsaturated fatty acid (FA) profile in eggs, including linoleic acid, and α-linolenic fatty acids known to increase egg weight and better human health respectively. However, the use of hemp products in animal feed is still a concern due to the potential residues of the Δ-9 tetrahydrocannabinol (THC), a psychoactive substance present in the hemp plant. No significant published research is available on the effect of dietary HSC on fatty acids profile and cannabinoids residues in organs and tissues of laying hens. The objectives of this study were to determine the effect of dietary HSC on the level of fatty acids composition, and cannabinoid transfer in eggs, as well as internal organs and tissues of laying hens.  Eight hundred caged Bovans white hens in at 30 weeks of age were distributed into 4 treatments of 200 hens per treatment based on inclusion levels of hemp seed cake (HSC) at 0, 10, 20 and 30% levels of inclusion. Each treatment group comprised of 8 cages of 25 hens each that served as replicates.  The observations per protocol were made over a timeline of 16 weeks following that precedes a 3-week acclimation phase.  HSC feeding to commercial laying hens increased (P<0.05) the levels of polyunsaturated fatty acids including linoleic and linolenic acids in eggs and abdominal fat. The cannabinoids residues in eggs, blood, breast meat, body fat, liver, kidneys and spleen were below the detectable level. The results of this study confirm that HSC fed to laying hens increased deposition of polyunsaturated fatty acids, but did not contribute THC or cannabinoid residues in eggs, internal organs or body tissues. Key words: Hemp, hemp seed cake (HSC), eggs, tetrahydrocannabinol (THC), fatty acids, cannabinoids

When is it safe to eat different broiler chicken tissues after administration of doxycycline and tylosin mixture?

Residues of veterinary drugs in poultry meat have serious health effects on humans (e.g., antimicrobial resistance, carcinogenicity, and hypersensitivity), which make the control of veterinary drug residues an important parameter in ensuring consumer protection. This work was performed to quantitatively determine two co-formulated anti-infective veterinary agents, tylosin tartrate (TYT) and doxycycline hydrochloride (DOX) in different tissues of broiler chickens (liver, muscles, and fat) using high performance liquid chromatography. The chickenwastreatedwiththerecommendeddoseofabinarymixtureofthedrugs(Tydovet). Moreover, the study aimed to estimate the withdrawal time of both drugs in chicken tissues. The analysis was done by solvent extraction and solid-phase extraction for clean-up of samples from the tissue matrix, followed by liquid chromatographic determination of the cited drugs with UV-detection. Residue decline with time was tracked, and both antibiotics were found to be more persistent in liver tissues than other tissues (muscle and fat). The effect of freezing and cooking was investigated on tissue residue levels. While freezing had little effect on the concentration of both antibiotics; cooking, as anticipated, led to a marked decline. Therefore, it is recommended to pay attention to the proper withdrawal periods before marketing to ensure the hygienic suitability of broilers edibles for safe human consumption. PRACTICAL APPLICATION: This novel study measures tylosin and doxycycline residues simultaneously in different tissues (muscle, fat, and liver) after administration of Tydovet powder to the broiler chicken. Residues in fat persisted for a longer time than in muscle in case of TYT, whereas the reverse was noticed in DOX.

The screening of organophosphorus, organochlorine and synthetic pyrethroid pesticides residues in beef fat by tandem solid-phase extraction technique

For regulatory monitoring of pesticides in environmental matrices, a multiresidue analysis through solid phase extraction (SPE) technique and using gas chromatographic determination of organochlorine(OC), organophosphorus(OP) and synthetic pyrethroid pesticides residues in beef fat was studied. The group of pesticides was added to dissolved beef fat (0.5 g) and blended with 8% de-activation florisil. The florisil/fat mixture was packed into disposable filtration columns. This column was tandem with an octadecyl SPE column and was eluted with acetonitrile. The pesticide residues were determined by gas chromatography with electron capture and flame photometric detectors. Three kinds (including OC, OP and synthetic pyrethroid) with a total of 71 pesticides (including their metabolites) were tested in this study. With the exception of isoxthion and flucythrinate with high recovery rates (122% ± 13% and 137% ± 31%, respectively), according to the correlation coefficients for the 71 extracted pesticide standard curves (ranging from 0.9915 ± 0.0176 to 0.9999 ± 0.0200, n = 5), average recovery rate (ranging from 68 ± 9% to 117 ± 11%, n = 25 for each insecticide), inter-assay variability (ranging from 3 ± 3% to 17 ± 12%, n = 25 for each insecticide), intra-assay variability(ranging from 3 to 19%, n = 5 for each insecticide) indicated that the methodology is acceptable for the extraction, determination, and screening of theses residues in beef fat. The detection limits for OCs, OPs and synthetic pyrethroid pesticides are 2-21 ng/g, 6-31 ng/g and 3-118 ng/g, respectively. Comparing with studies conducted by the National Analytical Reference Laboratory in Western Australia in the field of pesticide residue testing in beef fat, the results indicated that the present method could accurately measure commonly used pesticide chemicals.

Determination of the total tulathromycin residues in bovine muscle, fat, and liver by liquid chromatography-tandem mass spectrometry

A reliable and accurate liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based method was developed to quantify total tulathromycin residues in bovine tissues. Specifically, the above method relied on the quantification of CP-60,300, a marker produced by tulathromycin hydrolysis, for which maximum residue limits (MRLs) were established by the European Union and several other countries. Sample preparation and LC-MS/MS conditions were thoroughly optimized to allow for accurate quantification. The optimized procedure involved sample homogenization with 2 mol/L hydrochloric acid and ethyl acetate, heating of the resulting aqueous layer to convert tulathromycin and its metabolites into the marker residue, cleanup by a polymer-based cation-exchange cartridge, and subsequent analysis by LC-MS/MS. The developed method was validated for tulathromycin A and the marker residue in bovine muscle, fat, and liver at two levels, namely at the MRL set in Japan and at 0.01 mg/kg. Excellent analytical performance was observed, with the average recoveries of tulathromycin A and the marker residue ranging from 98 to 107%, and relative standard deviations ranging from 1 to 3%. Matrix effects were negligible, and analyte loss during sample preparation was minimal for all matrices tested, which allowed for accurate determination by external standard calibration using a solvent standard. No interfering peaks were observed close to the retention time of the marker residue for all matrices, which was indicative of high specificity. Overall, the developed method was proven suitable for regulatory purpose analysis of total tulathromycin residues.

Tissue residue depletion of moxidectin in lambs (Ovis aries) following subcutaneous administration

ABSTRACTTo date, a tissue depletion study of moxidectin (MOX) in lambs is not available. Thus, considering that lamb meat is of great commercial interest in the world, the aim of the present study was to determine the residue levels of MOX in lamb target-tissues (muscle, liver, kidney and fat) and subsequently calculate the MOX withdrawal period. For this purpose, the target-tissues were analysed by ultra-high-performance liquid chromatography-tandem mass spectrometry. Method validation was performed based on Commission Decision 2002/657/EC and VICH GL49. To quantify the analyte, matrix-matched analytical curves were constructed with spiked blank tissues. The limits of detection and quantitation were 1.5 and 5 ng g−1, respectively, for all matrices. The linearity, decision limit, detection capability accuracy and inter- and intra-day precision of the method are reported. The lambs were treated with a single subcutaneous dose of 0.2 mg MOX kg−1 body weight and were slaughtered in accordance with accepted animal care protocols. Samples of target-tissues were collected on 2, 4, 7, 14, 28 and 42 days after MOX administration. During the whole study, the highest drug residue level occurred in the fat. For the other target-tissues (muscle, liver and kidney), MOX concentrations were below the maximum residue limit (MRL). Considering the MRL value of 500 µg kg−1 for MOX residues in sheep fat, our results in lambs allowed the estimation of a MOX withdrawal period of 31 days. This indicates that the withdrawal period established for MOX in adult sheep (28 days) does not apply for lambs.

Determination of pyrethrin and pyrethroid residues in animal fat using liquid chromatography coupled to tandem mass spectrometry

A method was developed for the confirmatory and quantitative analysis of one pyrethrin and 18 pyrethroid residues in animal fat. Fat was extracted was collected from adipose tissue melted in an oven at 65 °C for 2 h. Fat samples (1 g) were dispersed with deactivated Florisil® sorbent and extracted with MeCN. Sample extracts were purified by cold temperature precipitation at −30 °C for 4 h and further purified using dispersive solid-phase extraction (d-SPE) clean-up in tubes containing 500 mg of Z-SEP+ and 125 mg of PSA bonded silica. Purified samples were analysed by ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC–MS/MS) detection. Chromatographic separation was carried out on a Acquity C8 BEH column, using a binary gradient separation comprising of mobile phase A, 5 mM ammonium formate in water:MeOH (80:20, v/v,) and mobile phase B, 5 mM ammonium formate in MeOH. The mass spectrometer was operated in the positive electrospray ionisation mode (ESI(+)). Validation was performed following the 2002/657/EC guidelines. Trueness ranged between 84% and 143% and precision ranged between 3.9% and 29%. The developed method is particularly advantageous because the sample preparation procedure does not require complex sample extraction equipment and uses less solvent compared to other sample preparation protocols.

Moxidectin residues in tissues of lambs submitted to three endoparasite control programs

The indiscriminate and continuous use of anthelmintic drugs has promoted the selection of resistant parasites population, the presence of drug residues in food products, and heavy environmental contamination. The aim of the present study was to determine the presence of antiparasitic drug residues in 42-days old lamb serum and tissues, submitted to three endoparasite control programs: preventive treatment (PT) using moxidectin (MOX) at every 28days; selective treatment (FEC) using MOX when fecal egg count was greater than or equal to 700; and selective treatment (FMC), using MOX when FAMACHA/FMC score was 3 and above. For this purpose, MOX residues were quantified in serum, muscle, fat, liver and kidney. Lambs were slaughtered when reaching 30kg of body weight, and after a 28-day MOX withdrawal period. Before slaughter, blood was collected to determine the concentration of MOX in serum. Tissues and organ samples were collected at slaughter. The quantitation of MOX residues was performed using liquid chromatography tandem mass spectrometry (LC-MS/MS). From the 756 tissue samples analyzed, only one sample of fat from the PT group showed residue levels (586.3μg/kg) above the maximum residue limit (MRL) of 500μg/kg. No treated lambs presented traces of MOX residues in fat and liver, suggesting possible environmental contamination. In conclusion, all weaned lambs, produced in continuous grazing and subjected to gastrointestinal parasite control programs via selective (FEC and FMC) or preventive (PT) treatment, displayed a low risk (<1%) of MOX residues above the MRL in muscle, fat, kidney, and liver.

Chloroorganic insecticides in the fat of different assortment of rainbow trout (Oncorhynchus mykiss) meat

Abstract The aim of the study was to determine the content of chlorinated hydrocarbon residues in fat of different assortment of rainbow trout (Oncorhynchus mykiss). The research material consisted of 108 fish from six different producers. Thirty-six fish were analysed as fresh, 36 fish as frozen after six months storage, and 36 fish as traditionally smoked. Chromatographic determination of γ-HCH, DDT, DDD, and DDE was performed with an Agilent Technologies 6890N. The presence of the compounds was detected in all tested fat samples. The content of γ-HCH was five-fold higher in frozen fish (average 2.11 ng/g of fat) than in fresh and smoked fish (0.42 ng/g of fat and 0.43 ng/g of fat, respectively). Total DDT (ΣDDT) content was found higher after refrigerated storage but did not exceed acceptable levels, indicating that the fat in the meat of rainbow trout is an attractive nutritional compound with a low concentration of tested chemical pollutants.

Chlorinated hydrocarbons residues in milk fat of selected farm animals from the north-eastern part of Poland

Abstract The aim of the study was to determine and compare the concentrations of chlorinated hydrocarbons residues (DDT, DDE, DDD, γ-HCH) in the milk fat of selected species of farm animals. The experiment was carried out on cow’s, sheep’s, goat’s, and mare’s milk samples originating from different parts of north-eastern Poland. The samples were prepared using Röse-Gottlieb’s and Ludwicki’s methods. The determination of the compounds was conducted with gas chromatography. All tested samples contained the residues of chlorinated hydrocarbons. The results varied depending on the animal species as well as the places of sample collections. The highest content of γ-HCH and ΣDDT was determined in cow’s milk (22.75; 53.12 μg/kg of fat, respectively). The lowest level of γ-HCH and ΣDDT was observed in sheep’s milk (0.25; 5.94 μg/kg of fat, respectively). The content of chlorinated hydrocarbons did not exceed the maximum acceptable levels of these compounds.

Influence of physiological status on residues of lipophilic xenobiotics in livestock

Data on the transfer of lipophilic xenobiotics from livestock feed and the environment to meat and milk are required for risk assessment purposes. Often, data are only available for lactating dairy cattle. Physiologically-based pharmacokinetic (PBPK) modeling has been used to explore differences between classes of food-producing animals. Blood and tissue levels of lipophilic xenobiotics under conditions approximating steady-state were simulated. Simulations of constant exposure were performed for lactating cows, non-lactating cattle, sheep, goats and swine. The tissue : blood partition coefficient, fat volume and fat blood flow were identified as critical determinants of predicted tissue concentrations. There may be significant breed differences in residues in milk and fat following exposure. Modeling was used to derive scaling factors that can be used to assist the extrapolation of transfer studies, carried out on lactating dairy cows, to other classes of cattle and different species.

Transfer of fat-soluble pesticides from contaminated feed to poultry tissues and eggs

1. Implementation of Good Manufacturing Practice and HACCP (Hazard Analysis Critical Control Points) in the production of poultry feed requires efficient tools for profiling risks associated with pesticide use in the production of crops for feed. 2. This paper describes a simple model that may be of use in the first tiers of risk profiling of feeds. 3. The model adequately reproduced the pattern of residues in fat and eggs of laying hens dosed with a selection of lipophilic pesticides that may be used in the production of crops for poultry feeds: deltamethrin, diflubenzuron, fipronil, lindane, piperonyl butoxide and spinosad. 4. Simulations suggest results derived from studies on laying chickens can be extrapolated to other laying birds. 5. Poultry meat production systems focus on maximising growth of birds giving rise to significant potential for dilution of residues that transfer to fat from feed. 6. Simulations of residues in fat of chickens, ducks, geese and turkeys exposed to a lipophilic pesticide with an elimination half-life of one day at 10 mg/kg body weight/d from hatching to typical market ages suggest residues in fat that are highest in turkeys > chickens > geese > ducks. 7. The model is of use in interpreting published dosing studies and predicting likely residues in birds at times after last exposure/dosing.

Development of a sensitive heterologous ELISA method for analysis of acetylgestagen residues in animal fat

A new heterologous ELISA method for detecting acetylgestagen multi-residues in animal fat was developed. An antibody generated has high cross-reactivity with relative progestogens (up to 50%) and no cross-reactivity with other steroids (<0.1%) in homologous ELISA. Three heterologous immunoassay were developed and one of them improved not only sensitivity but also the class-selectivity compared with the homologous assay against these progestogens. The IC 50 for four acetylgestagens, chlormadinone acetate (CMA), 17α-hydroxyprogesterone acetate (HPA), megestrol acetate (MEGA) and medroxyprogesterone acetate (MPA) were, 4.5, 2.5, 2.9 and 1.8 μg/L, respectively. The cross-reactivity for CMA, HPA and MEGA were 40%, 72% and 62% when they were compared with MPA. Progestogens recoveries from spiked swine fat averaged between 61% and 78%. Results obtained from LC/MS/MS method showed the heterologous ELISA method developed was reliable and suitable for rapid screening the four progestogens residues in fat tissues.

Dose‐dependent effects of melengestrol acetate (MGA) on plasma levels of estradiol, progesterone and luteinizing hormone in cycling heifers and influences on oestrogen residues in edible tissues

Melengestrol acetat (MGA) is widely used as a growth promoting feed additive in cattle breeding in the USA and several other non‐European countries. To explore the physiological effects of MGA four heifers were fed during 8 weeks with 0.5 mg MGA daily as registered in the USA and two heifers each received 0, 1.5 or 5 mg/day, respectively. Plasma samples were collected twice a week and concentrations of MGA, progesterone (P4) and estradiol‐17β (E2‐17β) were quantified. The pulsatile secretion of luteinizing hormone (LH) was investigated in 6‐hour profiles before and during treatment. After slaughter the reproductive organs were examined and oestrogen residues in edible tissues were measured. Four days after the beginning of MGA feeding MGA concentrations in plasma reached levels of 30 and 100–400 pg/mL depending on the dose received. Three weeks after the beginning of MGA feeding P4 plasma concentrations had dropped to base levels below 0.3 ng/mL in all three treatment groups. Mean plasma E2‐17β levels increased in physiological range from 1 to 5 pg/mL during 0.5 mg MGA/day feeding with many acyclic peaks. Overdosed MGA decreased E2 levels and suppressed cyclic peaks. Number and size of ovarian follicles were not altered by any treatment. Mean LH levels and pulse frequencies increased significantly during labelled treatment (0.5 mg/day), while higher doses had reducing effects. The development of corpus luteum was suppressed. E2‐17β residues in fat increased about 300% following labelled MGA treatment.

A sensitive enzyme immunoassay (EIA) for the determination of melengestrol acetate (MGA) in adipose and muscle tissues

The development of a sensitive screening method of MGA residues in bovine perirenal fat and muscle based on a competitive microtitration plate enzyme immunoassay is described. The samples were extracted with petroleum ether and purified with octadecyl-silica-cartridges. The detection limit for fat was 0.4ng/g and for muscle tissue 0.05ng/g, much lower than required for reliable detection of positive samples. The mean recovery rates of fortified samples amount to 75%, the mean intraassay variations to 7% and the interassay variation to 13%. Determination limits were validated for fat at 2ng/g and for muscle at 0.1ng/g. The efficiency of the new screening method was successfully demonstrated by the direct comparison to GC-MS and LC-MS methods performed at natural positive samples originating from an animal experiment in which the labelled dose (0.5mg per animal and day) with and without a 48h withdrawal period or 3-fold or 10-fold the amount of MGA, respectively, was fed to Holstein Frisian heifers. In conclusion, this new screening method can be used for sensitive determination of MGA residues in adipose tissues even after low treatment doses or longer withdrawal periods.

Confirmation of Moxidectin Residues in Cattle Fat by Liquid Chromatography/Mass Spectrometry

Moxidectin, a potent new endo- and ectoparasitic agent, is determined in cattle tissues by liquid chromatography (LC) with fluorescence detection. The original confirmatory method for moxidectin in cattle fat, the target tissue for regulatory purposes, was LC with mass spectrometry (MS) using thermospray (TSP) ionization and selected ion monitoring. As newer ionization techniques for LC/MS made TSP obsolete and with the availability of a new generation of benchtop LC/MS instrumentation, the confirmation of moxidectin in cattle fat was re-evaluated. The ionization techniques of atmospheric pressure chemical ionization versus electrospray ionization, the detection techniques of single-stage MS versus tandem MS, and the instrumentation of ion trap versus quadrupole were investigated. The final confirmatory method was based on full-scan single-stage MS. Even with full-scan detection, the analysis required at least 10-fold less extract than the original TSP method. The applicability of this new confirmatory method was demonstrated on both ion trap and quadrupole instruments.

Transfer of microcontaminants from sediment to chironomids, and the risk for the Pond bat Myotis dasycneme (Chiroptera) preying on them

Transfer ratios of metals, PCBs, pesticides and PAHs from the sediment to chironomid larvae and adults collected in a highly contaminated area, the Biesbosch, were studied. Metal concentrations in larvae were 0.28 (Cd), 0.02 (Cr), 0.52 (Cu), 0.06 (Hg), 0.03 (Pb), 0.32 (Zn) times those found in standard sediment, on a dry weight basis. Hg and Zn were well transported to the adult stage. Dry weight ratios of contaminant residues in adults and in larvae were 0.38 (Cd), 0.23 (Cr), 0.62 (Cu), 1.03 (Hg), 0.08 (Pb), 0.94 (Zn). For PCBs and pesticides, the concentration ratios of chironomid larvae fat to sediment (dry organic matter) varied around 3.3, which is consistent with laboratory studies. Organochlorine residues in adult fat were comparable to those in larvae lipids. However, the concentrations of non-ortho PCBs were 1.7 times higher in adults. For polycyclic aromatic hydrocarbons (PAH), larval fat:sediment (organic matter) concentration ratios ranged from 0.004 to 0.1. Adult: larvae ratios for PAHs varied between 0.2 and 0.6. For naphthalene a much higher transport ratio of 2 was found. Chironomid adults are the most important potential food source of the Pond bat, which lives in low densities in the Biesbosch. The contaminant concentrations measured in the chironomids do not exceed diet levels that are thought to be safe for mammals. However, Pond bats collected in less contaminated areas contained PCB-concentrations of 9, 33 and 76 mg kg−1 lipid weight, which are above concentrations that cause reproduction effects on Mink.

Physiologically based toxicokinetic model for maternal transfer of 2,3,7,8‐tetrachlorodibenzo‐p‐dioxin in brook trout (Salvelinus fontinalis)

AbstractA physiologically based toxicokinetic (PB‐TK) model was developed to describe the uptake, distribution, and elimination of 2,3,7,8‐tetrachlorodibenzo‐p‐dioxin (TCDD) in female brook trout during a 6‐month feeding and depuration study. Dietary uptake was modeled under two assumptions, uptake proceeds to equilibrium between blood exiting the intestinal tract and the contents of the intestinal tract, and uptake is limited by desorption of TCDD from gut contents and/or diffusion from the lumen into tissues. Model outputs were evaluated by comparison with measured TCDD residues. The best model fit to the data was obtained by imposing a moderate diffusion limitation on gut uptake. Of the parameters that comprise the gut submodel, whole body residue predictions were most sensitive to changes in the diffusion rate constant and fecal egestion rate. Chemical residues in fat were indicative of an internal disequilibrium with other tissues during the loading phase of the study. Accurate simulations of this behavior were obtained using a diffusion‐limited tissue description. Chemical residues in liver, muscle, and ovaries were adequately described by assuming that uptake and elimination were blood flow limited. Spawning probably resulted in a small increase in whole body TCDD concentration and did not appear to represent an important route of chemical elimination. These results suggest that field‐derived whole body TCDD residues could be used to estimate residues in developing ovaries of brook trout to within a factor of two, provided that whole body and ovary lipid content were known.

Organochlorine pesticide residues in buffaloe and cattle fat in Assiut Governorate

Organochlorine pesticide (OCP) residues in 519 samples; comprising eggs, chicken and meat (lamb and beef), collected from Jordan were determined. All samples were analyzed for their residual contents of aldrin, dichlorodiphenyltrichloroethane and metabolites (DDTs), dieldrin, endosulfan isomers, endrin, hexachlorocyclohexane isomers (HCHs), heptachlor, heptachlor epoxide and hexachlorobenzene (HCB). The samples were Soxhlet extracted for 8 h in 250 mL petroleum ether. The cleanup of the samples was performed by Florisil column chromatography and analysis was done on a gas chromatography equipped with an electron capture detector (GC-ECD). The results indicated that 28% (38/134), 20% (23/115) and 49% (131/270) of the examined eggs, chicken and meat samples, respectively, were contaminated with OCP residues. HCHs and DDTs are the most prominently noticed compounds, as they were detected at a high incidence. On the other hand, heptachlor, heptachlor epoxide, HCB, aldrin and endrin compounds were only present in less than 7% of the analyzed samples. These residues are present despite complete ban on the use of OCPs for agricultural purposes in Jordan. No residues of op′-DDD, op′-DDT, dieldrin, α-endosulfan and β-endosulfan were detected.

Modelling and monitoring organochlorine and heavy metal accumulation in soils, earthworms, and shrews in Rhine-delta floodplains.

In the Rhine-delta, accumulation of microcontaminants in floodplain foodwebs has received little attention in comparison with aquatic communities. To investigate organochlorine and metal concentrations in a terrestrial foodchain, samples of soil, earthworms (Lumbricus rubellus), and shrew (Crocidura russula, Sorex araneus) livers and kidneys were taken from two moderately to heavily polluted floodplains. Chlorobiphenyl residues in earthworm fat were 0.10 to 3.5 times the concentrations in soil organic matter, whereas ratios for other organochlorines varied between 0.87 and 8.8. These ratios are one order of magnitude lower than expected from laboratory experiments with earthworms, and laboratory and field studies on aquatic invertebrates. Bioconcentration ratios for heavy metals are in accordance with literature values for other locations, confirming the high potential for cadmium accumulation in Lumbricidae. Concentrations of organochlorines in shrew liver lipids were 1.0 to 13 times the residues in earthworm fat. These values are higher than lipid-corrected biomagnification ratios for laboratory rodents, but equal to those measured for benthivorous birds in the Rhine-delta. On a dry weight basis, kidney-earthworm ratios for cadmium were about one order of magnitude lower than previously reported values for insectivores. Soil concentrations of many compounds in both floodplains did not meet Dutch quality standards. Yet, hexachlorobenzene, chlorobiphenyl 153 (PCB153), gamma-hexachlorocyclohexane, sigma DDT, and dieldrin residues in earthworms and shrews did not exceed diet levels expected to be safe for endothermic species. An exception was noted for cadmium in worms and shrew kidneys. Heavy metal pollution in soil was close to levels that are critical to earthworms in laboratory studies. Cadmium concentrations in shrew kidneys were below levels suggested to be safe for Sorex araneus, but above those that were critical to the rat.