A frequent characteristic of earthworms collected from contaminated sites is that they show considerable variation in measured tissue chemical concentrations. What is not certain is whether this variation results from local scale heterogeneity in soil concentrations and associated variation in exposure or rather from systematic and biologically based differences in earthworm pollutant handling. To assess patterns of earthworm chemical uptake and associated variation, accumulation was investigated in two bespoke toxicokinetic studies with the organic chemicals chlorpyrifos and fluoranthene and in a reanalysis of two published toxicokinetic studies with the metals Pb and Cd. The analysis of all data-sets highlighted extensive variation around one compartment model fits. Such consistently high variability, despite the homogenous nature of exposure within the test systems, hints at extensive biological variation in earthworms within the pathways involved in pollutant handling (uptake, metabolism, excretion) which goes beyond the simple methodological variation of a single test. The identified variation between individuals has important implications in areas such as biomarker analyses and secondary poisoning assessment. Further it indicates the presence of substantive selectable variation in pollutant handling that could support the development of pollutant tolerance in earthworms.

The combined effect of a chemical (fluoranthene) and a nonchemical stress (reduced soil moisture content) to the widely distributed earthworm Lumbricus rubellus were investigated in a laboratory study. Neither fluoranthene (up to 500 μg/g) nor low soil moisture (15% below optimal) had a significant effect on the survival of the exposed worms, but a significant effect on reproduction (cocoon production rate) was found for both stressors ( p < 0.001 in both cases). The response of cocoon production to each stressor could be well described by a logistic model; this suggested that the joint effects may be applicable to description using the independent action (IA) model that is widely used in pharmacology and chemical mixture risk assessment [ 1 ]. Fitting of the IA model provided a good description of the combined stressor data (accounting for 53.7% of total variation) and was the most parsimonious model describing joint effect (i.e., the description of the data was not improved by addition of further parameters accounting for synergism or antagonism). Thus, the independent action of the two responses was further supported by measurement of internal fluoranthene exposure. The chemical activity of fluoranthene in worm tissue was correlated only with soil fluoranthene concentration and not with soil moisture content. Taken together these results suggest that the IA model can help interpret the joint effects of chemical and nonchemical stressors. Such analyses should, however, be done with caution since the literature data set suggests that there may be cases where interactions between stressors result in joint effects that differ significantly from IA predictions.

The eggs of gannets from two Scottish colonies (Ailsa Craig, Bass Rock) of golden eagles from the Hebrides and Highlands and of merlin eggs from the Scottish borders were analyzed for 52 PAHs, including 2-7 ring parent and alkylated PAHs. Phenanthrene was the most abundant PAH in gannet eggs from Ailsa Craig, and methylnaphthalenes predominated in the eggs from other locations and species. Most PAHs were detected in eggs but none were at likely embryotoxic concentrations. The sum concentrations for all the PAHs analyzed (3.1-5.7 ng g(-1) wet wt.) and for the U.S. EPA 16 priority PAHs (2.0-4.3 ng g(-1) wet wt.) did not differ significantly between species or locations. This uniform, low-level accumulation suggests background exposure to diffuse sources. PCA indicated that 3 ring parent and alkylated PAHs predominated in the eggs of merlins and gannets from Ailsa Craig and Hebridean golden eagles; other eggs had a more mixed profile. Source signature diagnostics largely suggested a petrogenic origin for the PAHs in the merlin eggs that we analyzed but otherwise gave equivocal results and further work is needed to determine which diagnostics can be successfully applied to PAHs in eggs.

7,8 . The presence of detectable PAHs residues and metabolites in the body tissues and eggs of some biota 9 indicates that exposure does occur. PAHs in birds are often associated with lipids, bioaccumulation tending to occur not only in the livers but also in eggs where residues can be two or three orders of magnitude higher than in livers 10 . Thus, eggs are good potential biomonitors for PAH contamination in the environment. The aim of this pilot study was to determine if there was evidence of widespread exposure of predatory birds to PAHs in Britain, as detected by measurement of egg concentrations. We compared concentrations of PAHs in gannet (Morus bassanus), golden eagles (Aquila chrysaetos) and merlin (Falco columbarius) eggs which were collected as part of the UK Predatory Bird Monitoring Scheme. Eleven PAHs were detected in =50% of the eggs and most (>90%) contained four or more compounds. These results suggest that the occurrence of PAHs in eggs is extensive, despite the high metabolic capacity of birds. The most frequently detected PAHs were the larger compounds, namely those with five rings (benzo(ghi)fluoranthene and cyclo(cd)pyrene, detected in =90% of the eggs) and four rings (present in =50% of the samples). All the PAHs that were quantified were detected in at least one gannet egg and one golden eagle egg except for naphthalene and dibenzothiophene (not detected in either species) and perylene (not detected in golden eagles).

livers 10 The aim of this pilot study was to determine if there was evidence of widespread exposure of predatory birds to PAHs in Britain, as detected by measurement of egg concentrations. We compared concentrations of PAHs in gannet (Morus bassanus), golden eagles (Aquila chrysaetos) and merlin (Falco columbarius) eggs which were collected as part of the UK Predatory Bird Monitoring Scheme. . Thus, eggs are good potential biomonitors for PAH contamination in the environment.

Fail-to-hatch kestrel (Falco tinnunculus) eggs collected at the end of the 1999 and 2005 breeding seasons from nest boxes in and around the city of Rome, Italy, were analyzed by gas chromatography with electron capture detection for their PCB content and for the presence of DDT derivatives and other organochlorines. Among the various PCBs, congeners 153 and 180 were detected in all the eggs and showed the highest concentrations. Eggs collected from the same nest from a polluted location in Rome during 2 different years showed similar type and number of PCB congeners. These data and the fact that eggs from another nest near a sulphate mine had, atypically, low-chlorinated congeners support the conclusion that eggs of this species, whose adults in the Mediterranean and continental Europe perform only short or no migration movements, might be indicative of local pollution. When multiple eggs in the same clutch were analyzed, the PCBs were similar in type but their concentration decreased within clutch, likely in parallel to the laying order.

Most organochlorine (OC) use has been banned in Spain, but these compounds are persistent and may still adversely affect predatory birds. Data generally are lacking, however. Residues of hexachlorobenzene, α‐hexachlorocyclohexane, lindane, hexachloro‐octahydro‐epoxy‐dimethanonaphthalene, DDT, dichlorodiphenyldichloroethane, dichlorodiphenyldichloroethylene (DDE), and polychlorinated biphenyls (PCBs) were measured in 22 failed eggs of booted eagles ( Hieraaetus pennatus ) and goshawks ( Accipiter gentilis ) from southeastern Spain; both species are declining in this region. Hexachloro‐octahydro‐epoxy‐dimethanon‐aphthalene, DDE, and sum PCB congener concentrations were significantly higher in booted eagle than in goshawk eggs, and an inverse relationship was found between shell thickness and DDE concentrations in booted eagles. Organochlorides may have been associated with the failure of some booted eagle eggs, but concentrations in booted eagle and goshawk eggs decreased over the period during which populations have dwindled. Thus, although OCs may be a contributory factor, they are unlikely to be the primary cause of the recent population declines in southeastern Spain.

The polycyclic aromatic hydrocarbons (PAHs) naphthalene, acenaphthylene, acenaphthene, fluorene, fluoranthene, pyrene, benzo[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, ideno[1,2,3,-cd]-pyrene, dibenz[a,h]anthracene, benzo[g,h,i]perylene and the polychlorinated biphenyls (PCBs) 8, 18, 28, 29, 31, 52, 77, 101, 105, 114, 118, 123, 126, 128, 138, 141, 149, 153, 156, 157, 163, 169, 170, 171, 180, 183, 187, 189, 194, 199, 201, 206, and 209 were measured in -200 rural soils across Great Britain (GB). Dominance of soil PAH profiles by heavier compounds (4-6 rings) provided initial evidence for the importance of source in governing soil PAH concentrations. No relationship was found between soil organic matter (SOM) and sum concentration of total and "heavy" PAHs, although there was a weak positive relationship with lighter compounds. A spatial statistical technique showed that highest soil PAH concentrations were usually found close to industrial/urban centers where presumably source intensity is highest. PCBs clustered into seven groups, five of which contained a single "dioxin like" PCB, one contained lighter congeners (2-4 chlorines), and one contained heavy congeners (5-10 chlorines). Linear regressions with SOM explained up to 24.3% of variation for the sum concentration of penta- to deca- congeners, but <1% for the lighter congener groups. No significant relationships were found with latitude. Spatial statistical techniques showed clusters of high soil PCB concentrations predominantly in west and south east GB, either associated with urbanized areas or on the West coast.

Biological indicators can be used to assess polluted sites but their success depends on the availability of suitable assays. The aim of this study was to investigate the performance of two earthworm biomarkers, lysosomal membrane stability measured using the neutral red retention assay (NRR-T) and the total immune activity (TIA) assay, that have previously been established as responsive to chemical exposure. Responses of the two assays were measured following in situ exposure to complexly contaminated field soils at three industrial sites as well as urban and rural controls. The industrial sites were contaminated with a range of metal (cadmium, copper, lead, zinc, nickel and cobalt) and organic (including polycyclic aromatic hydrocarbons) contaminants, but at concentrations below the 'New Dutch List' Intervention concentrations. Exposed earthworms accumulated both metals and organic compounds at the contaminated sites, indicating that there was significant exposure. No effect on earthworm survival was found at any of the sites. Biomarker measurements, however, indicated significant effects, with lower NRR-T and TIA found in the contaminated soils when compared to the two controls. The results demonstrate that a comparison of soil pollutant concentrations with guideline values would not have unequivocally identified chemical exposure and toxic effect for soil organisms living in these soils. However, the earthworm biomarkers successfully identified significant exposure and biological effects caused by the mixture of chemicals present.

Freeze-drying is used for the preparation and especially preservation of biological media but can cause dechlorination of organochlorine compounds and potential reductions in concentration through volatilisation. This study investigated the effect of freeze-drying on the measurable levels of 16 polychlorinated biphenyl (PCB) congeners naturally incorporated into avian liver. Freeze-drying significantly increased the concentrations of seven of the congeners and significantly decreased the variability in measurements on replicate samples.

Many species of bats roost in roof spaces and can come into contact with pesticides used to treat roof timbers against rot. As part of a study to develop a test with laboratory mice which could be used to predict the likely toxicity of pesticides to bats, the toxic effects on pipistrelle bats Pipistrellus pipistrellus and laboratory mice (CFLP outbred-strain) of exposure to dieldrin-treated timber were compared. Dose (amount of dieldrin applied to the wood surface) - response (mortality) studies demonstrated that pipistrelle bats were 30 times more sensitive to dieldrin-treated wood than laboratory mice. However, dieldrin residues in the brain and liver of animals which had been poisoned were significantly higher in bats than mice. These residue data suggest that bats may be inherently less sensitive to dieldrin poisoning than mice and so it is likely that the 30-fold greater sensitivity of bats than mice to dieldrin-treated timber was a result of greater rate of uptake, per gram body weight, of the active ingredient from the wood surface and/or slower clearance from the body. The importance of differences in exposure and the reliability of residue data as an indicator of differences in inherent sensitivity to a chemical are discussed in terms of their importance when considering inter-species variation in toxic response.