Contaminant exposure and effects in pinnipeds: implications for Steller sea lion declines in Alaska

Regional variations and drivers of essential and non-essential elements in Steller sea lion pups from the Aleutian Islands, Alaska

Exposure and resulting tissue concentrations of various elements from natural and anthropogenic sources are influenced by multiple factors, such as geographic location, age, diet, and metabolic rate, that can influence wildlife health. Essential and non-essential elements were assessed in lanugo and whole blood collected in 2019 from 102 Steller sea lion (Eumetopias jubatus) pups from two rookeries from the western and central Aleutian Islands: Agattu (WAI, n = 54) and Ulak Islands (CAI, n = 48). Rookery, sex, dorsal standard length, and trophic ecology (ẟ15N, ẟ13C values) effects on element concentration were evaluated. Significant differences in element concentrations of lanugo were exhibited across rookeries (p < 0.05), except for zinc (Zn). For example, higher mercury (Hg) and selenium (Se) concentrations were observed in WAI than CAI, while other elements were lower in WAI. Whole blood showed higher sulfur (S) and Se concentrations in CAI compared to WAI, while WAI had elevated strontium (Sr) and Hg concentrations relative to CAI. Trophic ecology significantly influenced most element concentrations, possibly due to regional variations in adult female feeding and food web dynamics. Interactions between elements were found in lanugo across both rookeries, with varying strengths. Whole blood displayed less pronounced yet consistent associations, with variable intensities. Essential elements sodium (Na), potassium (K), and calcium (Ca) formed a distinct group whose interaction is crucial for nervous system function and muscle contraction. Another group comprised zinc (Zn), iron (Fe), manganese (Mn), magnesium (Mg), phosphorous (P), S, and Se, which are known for indirectly interacting with enzyme function and metabolic pathways. Hg and Se formed a distinct group probably due to their known chemical interactions and physiological protective interactions.

The Commerson's dolphin as Subantarctic sentinel of POPs: insights into the pollutant status in one of the southernmost coastal areas of the globe

Persistent organic pollutants (POPs) are halogenated contaminants found globally. Cetaceans are impacted by these pollutants, and nowadays, it is essential to understand their presence to mitigate their impacts. This study aimed to establish baseline levels of POPs in the blubber of Commerson's dolphins (Cephalorhynchus commersonii) within the Subantarctic ecosystem. A wide range of POPs concentrations were measured among individuals: ΣPCBs from 289.5 to 15264 ng. g-1 lw and ΣDDTs from 540.4 to 17657 ng. g-1 lw. Levels of HCB and mirex ranged from 48 to 1703.7 ng. g-1 lw and 5.1 to 1917.4 ng. g-1 lw, respectively. The predominant POPs were mid- to high molecular weight PCBs (hexa-PCBs), consistent with other findings in cetaceans of the southern hemisphere. The mean ratio of ΣDDT/ΣPCB was 0.44, with p,p'-DDE/ΣDDT at 0.56, indicating p,p'-DDE as the dominant DDT isomer. Furthermore, differences in POP concentrations were observed based on sexual maturity, with mature males exhibiting higher levels of ƩPCBs, HCB, ƩDDT, and mirex. Age and total body length of animals were strongly correlated with POP concentrations. Our study provides valuable insights into the pollutant status of POPs in the Subantarctic population of Commerson's dolphins inhabiting the southernmost coastal regions of South America.

Persistent organic pollutants and polycyclic aromatic hydrocarbons in livers of stranded Arctocephalus australis in southern Brazilian beaches

23 livers of South American fur seal (Arctocephalus australis) found stranded in southern Brazilian beaches were evaluated for Persistent Organic Pollutants (POPs) and Polycyclic Aromatic Hydrocarbons (PAHs). POPs (DDTs, mirex, eldrin, dieldrin, aldrin, isodrin, HCHs, chlordanes and PCBs) and PAHs in livers were Soxhlet extracted, analyzed and quantified using Gas Chromatography Tandem Mass Spectrometry (GC-TQMS). The main POPs found were PCBs and DDTs, totaling 81 %. Among pesticides, mirex followed DDTs, possibly due to usage in Uruguay, followed by Σdrins, ΣCHLs and ΣHCHs. Naphthalene was the major PAH found, while heavier compounds did not significantly bioaccumulate. Concentrations of POPs resembled previous findings for A. australis. Considering only juveniles, no POPs showed significant differences between sexes. Lipidic content, weight and length did not show any correlation with POP concentration. This was the first record of PAHs and PBDEs in South American fur seals, and the levels of these pollutants were relatively low.

Metal-specific biomagnification and trophic dilution in the coastal foodweb of the California sea lion (Zalophus californianus) off Bahía Magdalena, Mexico: The role of the benthic-pelagic foodweb in the trophic transfer of trace and toxic metals

Trace metals concentrations along with stable isotopes ratios were measured in marine algae, sea grass, sponges, echinoderms, mollusks, crustaceans, fishes, and the California sea lion, to assess the bioaccumulation potential and detect potential risks for top predators off Bahia Magdalena, Mexico. We assessed the trophic magnification factor (TMF) to determine the potential for biomagnification of 11 trace metals. The concentrations of Fe and Zn were one order of magnitude higher than all other metals. Concentrations of As, Cu, Cd, Co, Cr, Fe, Mn and Ni correlated negatively with trophic level, supporting trophic dilution (TMF < 1, p > 0.05), while Zn and Hg had significant trophic magnification (TMF > 1, p < 0.05) when assessing only the benthic-pelagic foodweb. This research provides a baseline concentration of metals in multiple species, metal-specific foodweb bioaccumulation and biomagnification of mercury, underscoring the key role of the macrobenthic community as biovectors for trophic transfer of Hg through the foodweb to the California sea lion.

Effect of Ligustri Lucidi Fructus on myelosuppression in mice induced by cytoxan

In this study, we aimed to demonstrate the therapeutic effect of Ligustri Lucidi Fructus on chemotherapy-induced myelosuppression and elucidate its mechanism. A pharmacological study was conducted to investigate the mechanism of the inhibiting effects of Ligustri Lucidi Fructus on cyclophosphamide-induced bone marrow suppression in mice. HPLC was used to measure the chemical components. We demonstrated that medium and high doses of Ligustri Lucidi Fructus increased the amount of white blood cells and bone marrow nucleated cells (p < 0.05) in the cyclophosphamian-induced mouse model, and at the same time reduced granulocyte-macrophage-colony stimulating factor and thrombopoietin in the serum of myelosuppression mice (p < 0.01). Medium and high doses of Ligustri Lucidi Fructus can also adjust the thymus index and spleen index(p < 0.05). Ligustri Lucidi Fructus regulates the balance of bcl-2/bax, inhibits the expression of Caspase-3 and meanwhile stimulates the expression of mitogen-activated protein (MEK) and phospho extracellular regulated protein kinases (p-ERK) on the MAPK pathway. Five chemical constituents of Ligustri Lucidi Fructus, which may be related to myelosuppression, were analyzed. The content of specnuezhenide was 0.281%, that of ligustroflavone was 0.004%, that of salidroside was 0.094%, that of hydroxytyrosol was 0.060% and that of tyrosol was 0.069%. The effect of Ligustri Lucidi Fructus on myelosuppression after chemotherapy may be related to its multicomponent and multitarget nature. Ligustri Lucidi Fructus may be a promising potential drug for treatment after chemotherapy.

Trace Elements and Contaminants Concentrations in Tissues of Caspian Seals (Pusa caspica) along the Iranian Coast

The Caspian seal (Pusa caspica) is an endangered species that only lives in the Caspian Sea. Little information is available on its exposure to contaminants, and no data exists for Southern sub-populations. From 2011 to 2016, tissues samples were collected from 20 Caspian seals to (i) Define the concentration of trace elements in five different matrices and the concentration of 30 pesticides in their blubber; (ii) Determine whether differences in contaminant concentrations are age- or sex-related; (iii) Evaluate if detected concentrations can represent a risk to the species. Age- and sex-related variations were detected for Zn and Hg in the blubber and Fe in the kidney by age only. Exceptionally high Hg concentrations and low levels of hepatic Zn were detected, raising some concern about the reproductive health of seals. Similarly, the DDTs levels detected were in the range of adverse reproductive effects in marine mammals. Based on these results, potentially adverse effects on the immune and endocrine systems of the Caspian seal cannot be ruled out. Therefore, it is of the utmost importance that pollutant monitoring becomes an integral component of conservation strategies for the Caspian seal.

Regional, seasonal and age class blubber fatty acid signature analysis of harbour seals in Alaska from 1997 to 2010

Alaskan harbour seal populations are currently listed as a species of special concern. Although there is evidence of recent stabilization or even partial recovery of harbour seal numbers in areas of historic decline, most populations have not made substantial recoveries. To date, few data exist regarding spatial and seasonal changes in blubber fatty acids (FAs) for Alaskan harbour seal populations. The purpose of this study was to qualitatively investigate harbour seal blubber FA profiles for regional, seasonal and age class differences. Blubber FA concentrations were analysed using MANOVA and linear discriminant analysis (LDA) from 760 individual harbour seals across Bristol Bay, Kodiak, Prince William Sound and Southeast Alaska from 1997 to 2010. Our results suggest spatial and seasonal differences are largely driven by monounsaturated FAs, most notably 14:1n-5, 16:1n-7 and 18:1n-7. In addition, our data revealed a progression in blubber FAs from pups to adults, with a shift from saturated FAs and short-chained monounsaturated FAs in the pup blubber to more long-chain monounsaturated FAs and polyunsaturated FAs in adults. Lastly, harbour seals pups had elevated saturated FA 16:0 concentrations when compared to other age classes, regardless of location or period. With this vast spatial and seasonal FA information, we believe future sampling of blubber FAs from Alaskan harbour seal populations could be a useful tool in assessing the response of this species and its ecosystem to changes associated with natural and anthropogenic pressures.

Historic variation of trace elements in pinnipeds with spatially segregated trophic habits reveals differences in exposure to pollution

Marine mammals and the ecological functions they provide to coastal and pelagic ecosystems are increasingly threatened by the intensification of anthropogenic impacts. The Uruguayan coastline throughout the 20th century, like other coastal environments worldwide, has been the sink of a variety of trace metals derived from the rapid urbanization and industrialization of related land areas. This coastline is inhabited by two species of pinnipeds trophically and spatially segregated. Otaria byronia feeds in coastal environments while Arctocephalus australis preys mainly offshore. The present study aimed to analyze historic changes in concentrations of trace elements in teeth of both species from 1941 to the present day. We analyzed the dentin of 94 canine teeth using stable isotope analysis (δ¹³C) and ICP-MS to determine their feeding areas and the concentration of 10 trace elements (Al, As, Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) respectively. The concentration of Cr was significantly higher during '70-'80s, in both species coinciding with tannery industry development. Both species of pinnipeds have been differentially exposed to trace elements depending on their feeding area. A pelagic diet, possibly based on squid, increased the concentration of Cd in A. australis, while O. byronia has been more exposed to anthropogenic Pb and Cu associated to a costal and more benthic diet. Our results highlight dentin as a reliable matrix for historic studies on the exposure to trace elements. In light of our results, the O. byronia's declining population could be the result of the synergistic effects of trace elements together with other ecological pressures faced in their environment.

Bio-accumulation of organic contaminants in Indo-Pacific humpback dolphins: Preliminary unique features of the brain and testes

There is little information about the residue levels and congener composition of organic contaminants (OCs) in cetaceans. In the present study, we investigated the polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs) in the blubber, blood, brain and testes of Indo-Pacific humpback dolphins (Sousa chinensis) stranded in the Pearl River Estuary (PRE), China. The lowest blubber/tissue partition coefficients were found for sum hexachlorocyclohexanes (ΣHCHs) and ΣPAHs, while the highest were in ΣPCBs and sum dichlorodiphenyltrichloroethanes (ΣDDTs), likely attributing to the octanol-water partition features. The low levels of OCs in brain and testes theoretically resulted from the blood-brain barrier, blood-testes barrier, contaminant molecule dimensions and unique lipid compositions in the brain and testes. Compared with other contaminants, the higher mean brain/blood and testes/blood partition coefficients found for mirex, heptachlor, dieldrin and endrin would increase the risks associated with exposure-related toxicity and the bioavailability of contaminants within these tissues. Observations also suggest that as lipid mobilizes from blubber, contaminants may redistribute, leading to elevated tissue (such as brain) concentrations. Therefore, dolphins with less blubber may be more susceptible to health risks. The Indo-Pacific humpback dolphins living in PRE are at great risk due to variety of OCs in indirect contact with non-target organisms, affecting the health of animals (toxic effects and accumulation). Our findings contribute to the knowledge of the potential effects of OCs exposure on developmental neurotoxicity and reproductive damage in marine mammals.

Methyl mercury (MeHg) in vitro exposure alters mitogen-induced lymphocyte proliferation and cytokine expression in Steller sea lion (Eumetopias jubatus) pups

Steller sea lions (Eumetopias jubatus, SSLs) are managed as two distinct population segments within U.S. waters: the endangered western distinct population segment and the recently delisted eastern distinct population segment. Recent studies reported concentrations of mercury in several tissues collected from young SSLs in the Aleutian Islands that were at or above concentrations found to negatively impact health in other fish-eating mammals. However, there are limited studies which have investigated the range of mercury concentrations that may negatively influence the SSL immune system. This study assessed relationships between methyl mercury (MeHg⁺) concentrations and two immune functions, lymphocyte proliferation and cytokine expression. Peripheral blood mononuclear cells (PBMCs) were isolated and cryopreserved from pups on three rookeries within the western distinct population segment: Chiswell Island, Ulak, and Agattu Islands. Lymphocyte proliferation and cytokine expression were assessed in vitro using thawed PBMCs with exposure to MeHg⁺ (unexposed control, 0.001, 0.01, and 0.1 μg/ml). Lymphocyte proliferation was measured without and with stimulation with a T cell mitogen (ConA) and B cell mitogen (LPS) and the concentration of cytokines was measured in the cell culture supernatant (with and without ConA or LPS). Spontaneous lymphocyte proliferation was significantly increased at 0.01 and 0.1 μg/ml. T lymphocyte proliferation was significantly increased at 0.001 μg/ml and 0.1 μg/ml, while B lymphocyte proliferation was decreased at 0.1 μg/ml. Cytokine concentrations for INFγ, IL-10, IL-6, and TNFα were reduced at 0.1 μg/ml upon either T or B cell mitogen stimulation, with the exception for IL-10, where 0.1 μg/ml reduced IL-10 concentration compared to unstimulated cells. These data suggest immune functions were affected by MeHg⁺ exposure requiring in vivo follow up investigations. The observed modulation of immune functions is of concern as any toxicant-induced modulation may adversely affect the health of individuals, particularly younger animals undergoing periods of critical development.

Organochlorine contaminant concentrations in blubber of young Steller sea lion (Eumetopias jubatus) are influenced by region, age, sex, and lipid stores

Contaminant exposure is particularly important for species and populations of conservation concern, such as the Steller sea lion (Eumetopias jubatus). We used blubber samples (n = 120) to determine organochlorine concentrations, including polychlorinated biphenyls (PCBs) and dichloro-diphenyl-trichloroethane (DDTs), and blood samples (n = 107) to estimate total body lipids based on the hydrogen isotope dilution method. We assessed the influence of age, sex, condition, and geographic area on contaminant concentrations in blubber and contaminant body load. The concentration of ΣPCBs was highest in pups (<6 months) from the Aleutian Islands, and the concentrations in males were higher than females in all regions. The ΣPCBs and ΣDDTs concentrations and loads decreased with increasing mass in pups, however, there were no regional or sex differences in contaminant load. Within each of the five age classes, the concentrations of ΣPCBs and ΣDDTs decreased with increasing mass, but overall these OCs increased with age. Further, accounting for the lipid content, a potential proxy for energy balance, in the animal load reduced or removed the regional and sex effects present in age models for contaminants. We propose, that adjusting OCs concentration by the lipid content of the blubber sample alone may not fully account for the variability in OC concentrations associated with differences in condition or energy states between young Steller sea lions.

Uridine Diphosphate-Glucuronosyltransferase (UGT) 2B Subfamily Interspecies Differences in Carnivores

UDP-glucuronosyltransferases (UGTs) are among the most important xenobiotic metabolizing enzymes that conjugate a wide range of chemicals. Previous studies showed that Felidae and Pinnipedia species have very low UGT activities toward some phenolic compounds because of the UGT1A6 pseudogene and small numbers of UGT1A isozymes. In addition to the UGT1As, UGT2Bs isozymes also conjugate various endogenous (eg, estrogens, androgens, and bile acids) and exogenous compounds (opioids, non-steroidal anti-inflammatory drugs, and environmental pollutants). However UGT2B activity and genetic background are unknown in carnivore species. Therefore, this study was performed to elucidate the species differences of UGT2Bs. Using typical substrates for UGT2Bs, UGT activity was measured in vitro. In addition, UGT2B genetic features are analyzed in silico. Results of UGT activity measurement indicate marked species differences between dogs and other carnivores (cats, Northern fur seals, Steller sea lions, Harbor seals, and Caspian seals). Dogs have very high Vmax/Km toward estradiol (17-glucuronide), estrone, lorazepam, oxazepam, and temazepam. Conversely, cats and pinniped species (especially Caspian seals and Harbor seals) have very low activities toward these substrates. The results of genetic synteny analysis indicate that Felidae and pinniped species have very small numbers of UGT2B isozymes (one or none) compared with dogs, rodents, and humans. Furthermore, Felidae species have the same nonsense mutation in UGT2B, which suggests that Felidae UGT2B31-like is also a pseudogene in addition to UGT1A6. These findings of lower activity of UGT2B suggest that Felidae and some pinniped species have very low UGT activity toward a wide range of chemicals. These results are important for Felidae and Pinnipedia species that are frequently exposed to drugs and environmental pollutants.

Trace element concentrations in the Mediterranean monk seal (Monachus monachus) in the eastern Mediterranean Sea

The Mediterranean monk seal (Monachus monachus) is one of the most endangered marine mammals in the world. The biggest sub-population of the species survives in Greece, where understanding the effects of pollution on the survival of the species has been identified as a national research and conservation priority. From 1990 to 2013 we collected tissue samples from 59 deceased monk seals in order to: (i) Define the concentration of trace elements (As, Pb, Cd, Hg, Se, Cr, Ni) in three different matrices (i.e., blubber, liver and kidney), (ii) Determine whether differences in trace element concentrations are age- or gender-related, (iii) Evaluate the potential effects of these pollutants. The study recorded differences in trace element concentrations among matrices, but in general, trace element exposure in Mediterranean monk seals in Greece was low and within the non-acutely toxic levels for Pinnipeds. Only arsenic concentrations were at the upper limit of the normal range observed in other marine mammals (0.69±0.55mg/kg w.w. in blubber, 0.79±0.62mg/kg w.w. in liver and 0.79±0.59mg/kg w.w. in kidney). We recorded also exceptionally high Hg concentrations in a single adult female (24.88mg/kg w.w.). Age- and gender-related differences were also recorded and were due to various biological, ecological and chemical factors. Based on the results of the study, potentially adverse effects on the immune and endocrine system of the Mediterranean monk seal from some pollutants (e.g., As, Cd, Se, Ni, Cr) cannot be ruled out, which may expose the Mediterranean seal population in Greece to epizootics and stochastic phenomena of mass mortality. It is therefore of utmost importance that pollutant monitoring becomes an integral component of the standard monitoring protocol of the endangered Mediterranean monk seal in the eastern Mediterranean.

Screening of organic and metal contaminants in Australian humpback dolphins (Sousa sahulensis) inhabiting an urbanised embayment

As a marine mammal species that inhabits shallow nearshore waters, humpback dolphins are likely exposed to a wide range of pollutants from adjacent land-based activities. Increased mortality rates of Australian humpback dolphins (Sousa sahulensis) in waters off a major urbanised centre triggered investigations into the threats to these species, including their contaminant exposure. The present study utilised archived tissues from 6 stranded animals to screen for a range of pollutants (PCDD/Fs, PBDEs, PCBs, organochlorine pesticides, PAHs, organotins, essential and non-essential elements) to inform future biopsy based biomonitoring strategies. Concentrations of PCBs and DDXs in blubber of some of these animals were remarkably high, at levels near or above toxicological thresholds associated with immune- and reproductive toxicity or population declines in other marine mammals. PBDEs, PAHs, HCB, organotins, 'drins' as well as other organic pesticides were not detected, or present at relatively low concentrations. Profiles of elements were similar in epidermis compared to other tissues, and apart from some exceptions (e.g. Fe, Cr, Co, Cu) their concentrations fell within 25th-75th percentiles of cetacean baselines in four of the five animals. Non-essential elements (Al, V, Pb, Ba, Ni, Cd) were notably elevated in one specimen which may have experienced poor health or nutritional status. These data provide a first insight into the contaminant status of a rare and poorly studied population inhabiting an urbanised area. The results highlight a need for future biomonitoring of live populations, and inform on priorities in the typically limited blubber and skin sample volumes obtained through biopsies.

Organochlorine contaminant concentrations in multiple tissues of free-ranging Steller sea lions (Eumetopias jubatus) in Alaska

The relationships of selected organochlorine (OC) contaminants between blubber, blood, feces, and milk of young, free-ranging Steller sea lions (Eumetopias jubatus) were examined. Both between and within each tissue there was considerable individual variation. In spite of the variation, similar patterns were observed across the tissues for most of the selected PCB congeners. In all four tissues, the major PCB congeners were PCB101, PCB118, PCB138, and PCB153. The most prominent congener, both as a weight (ng/g lipid) and as a percentage of summed PCBs (∑PCBs), was PCB 153. Comparisons between paired tissues showed that ∑DDTs in blubber samples were related to concentrations in blood, feces, and milk. The ∑PCBs in blubber were related to concentrations in milk and fecal samples, though the relationship with feces was weak. Our findings show milk samples, in particular, are useful for assessing OCs in young sea lions. Blubber concentrations of PCB101, PCB118, and PCB138 were an order of magnitude higher than those in milk, supporting the biomagnification of these PCB congeners in SSL tissues. The findings indicate alternative tissues may be used as indicators of relative contaminant exposure in lieu of surgical blubber biopsy.

Deep-ocean foraging northern elephant seals bioaccumulate persistent organic pollutants

As top predators in the northeast Pacific Ocean, northern elephant seals (Mirounga angustirostris) are vulnerable to bioaccumulation of persistent organic pollutants (POPs). Our study examined a suite of POPs in blubber (inner and outer) and blood (serum) of free-ranging northern elephant seals. For adult females (N=24), we satellite tracked and sampled the same seals before and after their approximately seven month long foraging trip. For males, we sampled different adults and sub-adults before (N=14) and after (N=15) the same foraging trip. For females, we calculated blubber burdens for all compounds. The highest POP concentrations in males and females were found for ∑DDTs and ∑PCBs. In blubber and serum, males had significantly greater concentrations than females for almost all compounds. For males and females, ∑DDT and ∑PBDEs were highly correlated in blubber and serum. While ∑PCBs were highly correlated with ∑DDTs and ∑PBDEs in blubber and serum for males, ∑PCBs showed weaker correlations with both compounds in females. As females gained mass while foraging, concentrations of nearly all POPs in inner and outer blubber significantly decreased; however, the absolute burden in blubber significantly increased, indicating ingestion of contaminants while foraging. Additionally, we identified three clusters of seal foraging behavior, based on geography, diving behavior, and stable carbon and nitrogen isotopes, which corresponded with differences in ∑DDTs, ∑PBDEs, MeO-BDE 47, as well as the ratio of ∑DDTs to ∑PCBs, indicating the potential for behavior to heighten or mitigate contaminant exposure. The greatest concentrations of ∑DDTs and ∑PBDEs were observed in the cluster that foraged closer to the coast and had blood samples more enriched in (13)C. Bioaccumulation of POPs by elephant seals supports mesopelagic food webs as a sink for POPs and highlights elephant seals as a potential sentinel of contamination in deep ocean food webs.

PCB concentrations in plankton size classes, a temporal study in Marseille Bay, Western Mediterranean Sea

PCB levels in plankton were investigated in the Bay of Marseille, Western Mediterranean Sea, between September 2010 and October 2011. Concentrations of PCB congeners (CB 18, CB 52, CB 101, CB 118, CB 138, CB 153, CB 180) were determined in three plankton size-classes (60-200, 200-500 and 500-1000μm) together with different parameters: chlorophyll content, plankton dry-weight biomass, carbon and nitrogen stable isotope ratios and plankton-community structure. The ∑PCB7 concentrations ranged between 14.2 and 88.1ngg(-1)d.w., for all size classes and all sampling periods. The results do not show the biomass dilution effect and indicate moderate but significant biomagnification with plankton trophic position estimated by δ(15)N signatures. Equilibrium with water phase may notably contribute in controlling the PCB levels in the plankton. More generally, presented results imply that PCB accumulation in the plankton is an effect of abiotic and trophic complex interactions in the Bay of Marseille.

The effect of organohalogen contaminants on western Steller sea lion survival and movement in the Russian Far East

The western stock of Steller sea lions (Eumetopias jubatus) have experienced dramatic declines since the 1960s, particularly in the western Alaskan and Asian portions, which have continued to decline or stabilized at low levels. Multiple causes for this decline have been proposed and may include anthropogenic contamination from organohalogen contaminants (OCs). These include polychlorinated biphenyls (PCBs) and dichlorodiphenyltrichloroethane (DDT), which have not been ruled out as a potential cause for the lack of recovery. The objective of this study was to determine the effects of OCs on survival and movement probabilities estimated in program MARK using resighting data collected from 2003 to 2009. PCBs and DDTs were measured in whole blood from 136 (74 males and 62 females) individually marked, free-ranging pups from four Russian Far East rookeries. The mean concentration of ∑PCB and ∑DDT was 4.25±5.12 and 3.22±4.28 ng g(-1) ww (n=136), respectively, and the average ∑PCB and ∑DDT concentration for those above the aggregate mean (n=44) was 9.25±6.55 and 7.65±5.21 ng g(-1) ww, and those below the aggregate mean (n=92) the concentration was 1.86±0.89 and 1.11±0.65 ng g(-1) ww, respectively. The lowest estimated probabilities of survival occurred in the first year, ranging from 38% to 74%, but increased for ages 1-9, ranging from 82% to 94%. The greatest movement occurred from Medny Island west toward the Kamchatka Peninsula (33%) and to Bering Island (18%), and low movement estimates for other natal rookeries was largely due to minimal resighting effort. The estimated probabilities of resighting varied by location (48%-87%), but had greater precision than survival or movement parameters. Survival and movement were most affected by age and location rather than OCs.

Selenium and mercury concentrations in harbor seals (Phoca vitulina) from central California: health implications in an urbanized estuary

We measured total selenium and total mercury concentrations ([TSe] and [THg]) in hair (n=138) and blood (n=73) of harbor seals (Phoca vitulina) from California to assess variation by geography and sex, and inferred feeding relationships based on carbon, nitrogen, and sulfur stable isotopes. Harbor seals from Hg-contaminated sites had significantly greater [THg], and lesser [TSe] and TSe:THg molar ratios than seals from a relatively uncontaminated site. Males had significantly greater [THg] than females at all locations. Sulfur stable isotope values explained approximately 25% of the variability in [THg], indicating increased Hg exposure for seals with a greater use of estuarine prey species. Decreased [TSe] in harbor seals from Hg-contaminated regions may indicate a relative Se deficiency to mitigate the toxic effects of Hg. Further investigation into the Se status and the potential negative impact of Hg on harbor seals from Hg-contaminated sites is warranted.

Effects of age, adipose percent, and reproduction on PCB concentrations and profiles in an extreme fasting North Pacific marine mammal

Persistent organic pollutants, including polychlorinated biphenyls (PCBs), are widely distributed and detectable far from anthropogenic sources. Northern elephant seals (Mirounga angustirostris) biannually travel thousands of kilometers to forage in coastal and open-ocean regions of the northeast Pacific Ocean and then return to land where they fast while breeding and molting. Our study examined potential effects of age, adipose percent, and the difference between the breeding and molting fasts on PCB concentrations and congener profiles in blubber and serum of northern elephant seal females. Between 2005 and 2007, we sampled blubber and blood from 58 seals before and after a foraging trip, which were then analyzed for PCBs. Age did not significantly affect total PCB concentrations; however, the proportion of PCB congeners with different numbers of chlorine atoms was significantly affected by age, especially in the outer blubber. Younger adult females had a significantly greater proportion of low-chlorinated PCBs (tri-, tetra-, and penta-CBs) than older females, with the opposite trend observed for hepta-CBs, indicating that an age-associated process such as parity (birth) may significantly affect congener profiles. The percent of adipose tissue had a significant relationship with inner blubber PCB concentrations, with the highest mean concentrations observed at the end of the molting fast. These results highlight the importance of sampling across the entire blubber layer when assessing contaminant levels in phocid seals and taking into account the adipose stores and reproductive status of an animal when conducting contaminant research.

Coupling Fenton and biological oxidation for the removal of nitrochlorinated herbicides from water

The combination of Fenton and biological oxidation for the removal of the nitrochlorinated herbicides alachlor, atrazine and diuron in aqueous solution has been studied. The H2O2 dose was varied from 20 to 100% of the stoichiometric amount related to the initial chemical oxygen demand (COD). The effluents from Fenton oxidation were analyzed for ecotoxicity, biodegradability, total organic carbon (TOC), COD and intermediate byproducts. The chemical step resulted in a significant improvement of the biodegradability in spite of its negligible or even slightly negative effect on the ecotoxicity. Working at 60% of the stoichiometric H2O2 dose allowed obtaining highly biodegradable effluents in the cases of alachlor and atrazine. That dose was even lower (40% of the stoichiometric) for diuron. The subsequent biological treatment was carried out in a sequencing batch reactor (SBR) and the combined Fenton-biological treatment allowed up to around 80% of COD reduction.

PBDE flame retardants and PCBs in migrating Steller sea lions (Eumetopias jubatus) in the Strait of Georgia, British Columbia, Canada

Polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) were measured in blubber biopsy samples from 22 live-captured Steller sea lions (Eumetopias jubatus) that had just entered the Strait of Georgia, British Columbia, Canada, for their overwintering feeding season. ∑PBDE ranged from 50μgkg(-1) (lipid weight) in adult females to 3780μgkg(-1) in subadult individuals. ∑PCBs ranged from 272μgkg(-1) in adult females to 14280μgkg(-1) in subadult individuals. While most PBDE and PCB congeners were transferred through milk to pups, PCBs with logK(OW)>7.0 (PCBs 206, 207, 208 and 209) appeared constrained, resulting in a lighter mixture in pups compared to adult females. The ratio of individual PCB congeners by metabolic group (Groups I, II, III, IV and V) to PCB-153 regressed against length of males suggested poor biotransformation of these compounds (slopes did not differ from zero, p>0.05). PBDE congeners 49, 99, 153 and 183 appeared bioaccumulative (slopes of ratio BDE/PCB 153 versus length were higher than zero, p<0.05), but the dominance of the single congener, BDE-47 (64% of total PBDEs), likely due in part to debromination pathways, reduced our ability to explore congener-specific dynamics of PBDEs in these pinnipeds. With 80% of our Steller sea lions exceeding a recent toxicity reference value for PCBs, the fasting-associated mobilization of these contaminants raises concerns about a heightened vulnerability to adverse effects during annual migrations.

Quantification of total mercury in liver and heart tissue of Harbor Seals (Phoca vitulina) from Alaska USA

This study quantified the Hg levels in the liver (n=98) and heart (n=43) tissues of Harbor Seals (Phoca vitulina) (n=102) harvested from Prince William Sound and Kodiak Island Alaska. Mercury tissue dry weight (dw) concentrations in the liver ranged from 1.7 to 393 ppm dw, and in the heart from 0.19 to 4.99 ppm dw. Results of this study indicate liver and heart tissues' Hg ppm dw concentrations significantly increase with age. Male Harbor Seals bioaccumulated Hg in both their liver and heart tissues at a significantly faster rate than females. The liver Hg bioaccumulation rates between the harvest locations Kodiak Island and Prince William Sound were not found to be significantly different. On adsorption Hg is transported throughout the Harbor Seal's body with the partition coefficient higher for the liver than the heart. No significant differences in the bio-distribution (liver:heart Hg ppm dw ratios (n=38)) values were found with respect to either age, sex or geographic harvest location. In this study the age at which Hg liver and heart bioaccumulation levels become significantly distinct in male and female Harbor Seals were identified through a Tukey's analysis. Of notably concern to human health was a male Harbor Seal's liver tissue harvested from Kodiak Island region. Mercury accumulation in this sample tissue was determined through a Q-test to be an outlier, having far higher Hg concentrarion (liver 392Hgppmdw) than the general population sampled.

The cytotoxicity and genotoxicity of hexavalent chromium in Steller sea lion lung fibroblasts compared to human lung fibroblasts

In this study we directly compared soluble and particulate chromate cytotoxicity and genotoxicity in human (Homo sapiens) and sea lion (Eumetopias jubatus) lung fibroblasts. Our results show that hexavalent chromium induces increased cell death and chromosome damage in both human and sea lion cells with increasing intracellular chromium ion levels. The data further indicate that both sodium chromate and lead chromate are less cytotoxic and genotoxic to sea lion cells than human cells, based on an administered dose. Differences in chromium ion uptake explained some but not all of the reduced amounts of sodium chromate-induced cell death. By contrast, uptake differences could explain the differences in sodium chromate-induced chromosome damage and particulate chromate-induced toxicity. Altogether they indicate that while hexavalent chromium induces similar toxic effects in sea lion and human cells, there are different mechanisms underlying the toxic outcomes.

Geographic variation of persistent organic pollutant levels in humpback whale (Megaptera novaeangliae) feeding areas of the North Pacific and North Atlantic

Seasonal feeding behavior and high fidelity to feeding areas allow humpback whales (Megaptera novaeangliae) to be used as biological indicators of regional contamination. Biopsy blubber samples from male individuals (n = 67) were collected through SPLASH, a multinational research project, in eight North Pacific feeding grounds. Additional male samples (n = 20) were collected from one North Atlantic feeding ground. Persistent organic pollutants were measured in the samples and used to assess contaminant distribution in the study areas. North Atlantic (Gulf of Maine) whales were more contaminated than North Pacific whales, showing the highest levels of polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and chlordanes. The highest dichlorodiphenyltrichloroethane (DDT) levels were detected in whales feeding off southern California, USA. High-latitude regions were characterized by elevated levels of hexachlorocyclohexanes (HCHs) but generally nondetectable concentrations of PBDEs. Age was shown to have a positive relationship with SigmaPCBs, SigmaDDTs, Sigmachlordanes, and total percent lipid. Contaminant levels in humpback whales were comparable to other mysticetes and lower than those found in odontocete cetaceans and pinnipeds. Although these concentrations likely do not represent a significant conservation threat, levels in the Gulf of Maine and southern California may warrant further study.

Particulate and soluble hexavalent chromium are cytotoxic and genotoxic to Steller sea lion lung cells

Hexavalent chromium is an environmental contaminant. Within the environment, marine waters are a common site for hexavalent chromium deposition. We have recently reported significantly high levels of chromium in skin tissue from North Atlantic right whales. These findings demonstrate that marine species are being exposed to chromium. It is possible that such exposures may be playing a role in population declines evident among certain marine mammals, such as the Steller sea lion. We developed a Steller sea lion lung cell line from Steller sea lion lung tissue. Hexavalent chromium was cytotoxic to these primary lung fibroblasts as 1, 2.5, 5, 10 and 25microM sodium chromate induced 104, 99, 92, 58 and 11% relative survival, respectively. It was also genotoxic as 0, 1, 2.5, 5 and 10microM sodium chromate damaged chromosomes in 6, 11, 21, 36, and 39% of metaphases and damaged 6, 12, 27, 49 and 57 total aberrations in 100 metaphases, respectively. We also considered the toxicity of particulate hexavalent chromium, as it is the more potent carcinogen in humans. We found that 0.1, 0.5, 1, 5 and 10microg/cm(2) particulate chromate induced 95, 88, 91, 70, and 52% relative cell survival, respectively. These concentrations were genotoxic and damaged chromosomes in 9, 13, 18, and 23% of metaphases and induced 9, 15, 20 and 30 total aberrations per 100 metaphases, respectively. These data indicate that if sufficiently exposed, chromium may adversely affect the struggling Steller sea lion population. It would be prudent to investigate the effects chromium has in other Steller sea lion organs in order to derive a better understanding of how chromium in the marine environment may be affecting the declining Steller sea lion population.

Synergistic immunostimulating activity of pidotimod and red ginseng acidic polysaccharide against cyclophosphamide-induced immunosuppression

We investigated the synergistic effect of combined treatment with red ginseng acidic polysaccharide (RGAP) from Panax ginseng C.A. Meyer and pidotimod in cyclophosphamide-treated mice. The combination of pidotimod and RGAP restored concanavalin A-induced splenic T cell proliferation and LPS-stimulated B cell proliferation significantly. The production of nitric oxide from peritoneal macrophages was increased by the combinations. NK cell activity was increased by RGAP alone or in combination with pidotimod. A synergistic increase in the level of serum IL-12 and interferongamm was observed when the combination of the two was used. RGAP alone or in combination with pidotimod modulated the level of serum C-reactive protein to a near-normal level. These results indicate that combinations of pidotimod and RGAP are synergistic and suggest that combination therapy using pidotimod and RGAP for improving immune activity may provide an additional benefit over the use of the two drugs by themselves.

Advances and trends in the molecular systematics of anisakid nematodes, with implications for their evolutionary ecology and host-parasite co-evolutionary processes

The application of molecular systematics to the anisakid nematodes of the genera Anisakis, Pseudoterranova and Contracaecum, parasites of aquatic organisms, over the last two decades, has advanced the understanding of their systematics, taxonomy, ecology and phylogeny substantially. Here the results of this effort on this group of species from the early genetic works to the current status of their revised taxonomy, ecology and evolutionary aspects are reviewed for each of three parasitic groups. It has been shown that many anisakid morphospecies of Anisakis, Contracaecum and Pseudoterranova include a certain number of sibling species. Molecular genetic markers provided a rapid, precise means to screen and identify several species that serve as definitive and intermediate and or/paratenic hosts of the so far genetically characterized species. Patterns of differential distribution of anisakid nematodes in various definitive and intermediate hosts are presented. Differences in the life history of related species can be due both to differential host-parasite co-adaptation and co-evolution, and/or to interspecific competition, that can reduce the range of potential hosts in sympatric conditions. Phylogenetic hypotheses attempted for anisakid nematodes and the possible evolutionary scenarios that have been proposed inferred from molecular data, also with respect to the phylogeny of their hosts are presented for the parasite-host associations Anisakis-cetaceans and Contracaecum-pinnipeds, showing that codivergence and host-switching events could have accompanied the evolution of these groups of parasites. Finally, examples in which anisakid nematodes recognized genetically at the species level in definitive and intermediate/paratenic hosts from various geographical areas of the Boreal and Austral regions and their infection levels have been used as biological indicators of fish stocks and food-web integrity in areas at high versus low levels of habitat disturbance (pollution, overfishing, by-catch) are presented.

Metal tissue levels in Steller sea lion (Eumetopias jubatus) pups

The endangered Western population of the Steller sea lion declined for three decades for uncertain reasons. We present baseline data of metal concentrations in pups as a first step towards investigating the potential threat of developmental exposures to contaminants. Seven metals were investigated: arsenic, cadmium, silver, aluminum, mercury, lead and vanadium. Vanadium was detected in only a single blubber sample. Mercury appears to be the most toxicologically significant metal with concentrations in the liver well above the current action level for mercury in fish. The concentrations of aluminum, arsenic, silver, cadmium and lead were present in one-fourth to two-thirds of all samples and were at either comparable or below concentrations previously reported. Neither gender nor region had a significant effect on metal burdens. Future work should consider metal concentrations in juveniles and adults and toxicological studies need to be performed to begin to assess the toxicity of these metals.

Organochlorine contaminants in endangered Steller sea lion pups (Eumetopias jubatus) from western Alaska and the Russian Far East

Investigations into the cause of the Steller sea lion population decline have focused on numerous factors, including exposure to toxic contaminants such as organochlorines (OCs). OCs, such as polychlorinated biphenyls (PCBs), 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane, or dichlorodiphenyltrichloroethane (DDT), have been associated with various biological effects in marine mammals. We measured these compounds in whole blood of free-ranging Steller sea lion pups in order to determine the extent and magnitude of contamination across their geographical range. Of 212 pups analyzed for OCs, 76 pups (36 females and 40 males) were from western Alaska and the other 136 (63 females and 73 males) were from the Russian Far East. Concentrations of summation SigmaPCBs in the whole blood of pups from western Alaska ranged from 0.21 to 13 ng/g wet weight with a mean of 2.1+/-0.27 ng/g wet weight. In the Russian animals, summation SigmaPCB concentrations in the whole blood of pups ranged from 0.33 to 36 ng/g wet weight with a mean of 4.3+/-0.44 ng/g wet weight. summation SigmaDDT concentrations in the whole blood of pups from western Alaska ranged from 0.18 to 11 ng/g wet weight with a mean of 1.6+/-0.23 ng/g wet weight. In Russia, summation SigmaDDT in the whole blood of pups ranged from undetectable to 26 ng/g wet weight with a mean of 3.3+/-0.36 ng/g wet weight. Average OC concentrations were significantly higher in the blood of Russian animals compared to western Alaska (for PCBs and DDTs, p<0.001) and in both areas females had higher concentrations than males. Male pups from western Alaska had significantly lower levels of summation SigmaPCBs and summation SigmaDDT when compared to male pups from Russia (for PCBs and DDTs p<0.001). Female pups from western Alaska were significantly lower in summation SigmaPCBs than Russian female pups (for PCBs p=0.009) as were female pups for summation SigmaDDT levels between areas (for DDTs p=0.026). OC contaminants data indicate that Steller sea lion pups have measurable concentrations of these synthetic chemicals. While any physiological effect and the specific role these chemicals may have in either the decline or the failure of the endangered Steller sea lion population to recover needs to be further investigated, this study indicates specific areas and animals that may be most at risk.

Changes in blubber contaminant concentrations in California sea lions (Zalophus californianus) associated with weight loss and gain during rehabilitation

California sea lions have high levels of persistent organic pollutants (POPs) in their blubber. Animals affected by domoic acid fast and refeed during their rehabilitation. We studied the effect of decreases in total body mass (16 +/- 7% of initial body mass) on blubber POP contaminant concentrations and estimated POP burdens during fasting (12 +/- 5 days) in 19 California sea lions. The effect of refeeding (92 +/- 8% of initial body mass) was also investigated. Significant increases in the concentration of all POPs were found over the mass loss period and decreases during mass gain. A basic mass balance model indicated that the changes did not conform to a simple concentrating and diluting pattern and a proportion of the contaminants were lost from the lipid pool. During mass loss, the lower chlorinated polychlorinated biphenyl congeners, chlordanes, and hexachlorocyclohexanes were lost at a higher rate than the other contaminant classes (particularly polybrominated diphenyl ethers). During mass gain the behavior of all contaminant classes was more consistent with the dilution model. These results indicate the importance of considering the energetic contextwhen sampling blubberfor long-term contaminant monitoring and suggest an initial approach to adjust for such differences.

Biodegradation of agricultural herbicides in sequencing batch reactors under aerobic or anaerobic conditions

This study investigated the biodegradability of the herbicides isoproturon and 2,4-dichlorophenoxyacetic acid (2,4-D) in sequencing batch reactors (SBRs). Two laboratory-scale (2L liquid volume) SBRs were employed: one reactor performing under aerobic and the other under anaerobic conditions. The aerobic SBR was operated at an ambient temperature (22+/-2 degrees C), while the anaerobic SBR was run in the lower mesophilic range (30+/-2 degrees C). Each bioreactor was seeded with a 3:1 mixture (by weight) of fresh sludge and biomass that had been previously exposed to both herbicides. The effect of herbicide concentration on either treatment process was explored at a hydraulic retention time (HRT) of 48 h, using glucose as a supplemental carbon substrate. Although no isoproturon degradation was observed in either system during the study, complete 2,4-D removal occurred after an acclimation period of approximately 30 d (aerobic SBR) and 70 d (anaerobic SBR). The aerobic reactor achieved complete 2,4-D utilization at feed concentrations up to 500 mg/L. A further increase to 700 mg/L, however, proved to be inhibitory since 2,4-D biodegradation was negligible. On the other hand, the anaerobic SBR was able to degrade 120 mg/L of 2,4-D, which corresponds to 40% of the maximum feed concentration applied. Moreover, glucose was consumed first throughout the experiment in a sequential utilization pattern relating to 2,4-D, with biodegradation of both substrates following closely first-order kinetics.

Age-structured modeling reveals long-term declines in the natality of western Steller sea lions

Since the mid-1970s, the western Steller sea lion (Eumetopias jubatus), inhabiting Alaskan waters from Prince William Sound west through the Aleutian Islands, has declined by over 80%. Changing oceanographic conditions, competition from fishing operations, direct human-related mortality, and predators have been suggested as factors driving the decline, but the indirect and interactive nature of their effects on sea lions have made it difficult to attribute changes in abundance to specific factors. In part, this is because only changes in abundance, not changes in vital rates, are known. To determine how vital rates of the western Steller sea lion have changed during its 28-year decline, we first estimated the changes in Steller sea lion age structure using measurements of animals in aerial photographs taken during population surveys since 1985 in the central Gulf of Alaska (CGOA). We then fit an age-structured model with temporally varying vital rates to the age-structure data and to total population and pup counts. The model fits indicate that birth rate in the CGOA steadily declined from 1976 to 2004. Over the same period, survivorship first dropped severely in the early 1980s, when the population collapsed, and then survivorship steadily recovered. The best-fitting model indicates that in 2004, the birth rate in the central Gulf of Alaska was 36% lower than in the 1970s, while adult and juvenile survivorship were close to or slightly above 1970s levels. These predictions and other model predictions concerning population structure match independent field data from mark-recapture studies and photometric analyses. The dominant eigenvalue for the estimated 2004 Leslie matrix is 1.0014, indicating a stable population. The stability, however, depends on very high adult survival, and the shift in vital rates results in a population that is more sensitive to changes in adult survivorship. Although our modeling analysis focused exclusively on the central Gulf of Alaska, the western Gulf of Alaska and eastern Aleutians show a similar pattern of declining pup fraction with no increase in the juvenile, or pre-breeding, fraction. This suggests that declining birth rate may be a problem for western Steller sea lions across the Gulf of Alaska and into the Aleutian Islands.

Genetic diversity and infection levels of anisakid nematodes parasitic in fish and marine mammals from Boreal and Austral hemispheres

Anisakid nematodes have complex life-cycles that include invertebrate and vertebrate hosts at various levels of the marine food chain. Different types of habitat disturbances of the marine ecosystem (pollution, overfishing, by-catch) could impoverish the host population size, resulting in concomitant and detrimental effects on parasitic nematode populations. This in turn would lead to the loss of genetic diversity of these parasites at both the species and population levels. In order to test for a correlation existing between the genetic diversity of anisakid nematodes and habitat disturbance, the genetic variability, estimated by nuclear markers (19 allozyme loci), was evaluated among several anisakid populations from fish and marine mammals in various areas of the Boreal and Austral regions. Antarctic and sub-antarctic populations showed significantly (P<0.001) higher levels of genetic diversity (on average, He=0.23) than those from the Arctic and sub-Arctic populations and species (on average, He=0.07). Correlations between the degree of genetic variability and the levels of parasitic infections within their hosts were considered. Data revealed higher intensities in anisakid infections in Antarctic and sub-Antarctic hosts, presumably resulting from a lower degree of habitat disturbance in less stressed areas. The absence of disturbance presumably allowed anisakid species to reach a larger population size, with a reduced probability of genetic drift in their gene pools. This suggests that anisakid nematodes, and their levels of genetic diversity may be suitable indicators of the integrity of marine food webs and of the general biodiversity of a marine ecosystem.

The immunosuppressive effects of 10mg/kg cyclophosphamide in Wistar rats

The purpose of this study is to identify the immunosuppressive effects of cyclophosphamide (a known immunosuppressant) in male Wistar rats which were administered orally for 30 days repeatedly, and to find a proper dose of cyclophosphamide at which the immunosuppressive effects is identified. The dose of cyclophosphamide is 2, 5, 10mg/kg bw, respectively. The results showed that 10mg/kg cyclophosphamide treatment induced decreases in body weight, body weight gain, relative weight of spleen and thymus, antibody plaque-forming cells, delayed-type hypersensitivity reaction, natural killer cell activity, lipopolysaccharide-induced B-cell proliferation, and Concanavalin A-induced T-cell proliferation. The histopathology observation on spleen and thymus revealed as decreased cellularity. But, no significant clinical symptoms of toxicities and stress were observed and no rats died. These results indicated that the immunosuppressive effects of 10mg/kg cyclophosphamide dosed for 30 days orally were identified in male Wistar rats. Based on the results, it is considered that the dose of 10mg/kg of cyclophosphamide orally for 30 days in male Wistar rats could be used as the dose of positive control group for chemicals immunotoxicity assessment tests. This study also proved that the testing procedures and the experimental techniques established in our laboratory for immunotoxicity tests in male Wistar rats are reliable and feasible.