Accumulation and distribution of organochlorines (PCBs and DDTs) in various organs of Stenella coeruleoalba and a Tursiops truncatus from Mediterranean littoral environment (France)

Polychlorinated biphenyls in mussels, small pelagic fish, tuna, turtles, and dolphins from the Croatian Adriatic Sea waters: an overview of the last two decades of monitoring

This review summarises our two decades of polychlorinated biphenyl (PCB) monitoring in different marine organisms along the eastern Adriatic Sea. The aim was to gain an insight into the trends of PCB distribution in order to evaluate the effectiveness of past and current legislation and suggest further action. Here we mainly focus on PCB levels in wild and farmed Mediterranean mussels, wild and farmed bluefin tuna, loggerhead sea turtles, common bottlenose dolphins, and small pelagic fish. The use of artificial intelligence and advanced statistics enabled an insight into the influence of various variables on the uptake of PCBs in the investigated organisms as well as into their mutual dependence. Our findings suggest that PCBs in small pelagic fish and mussels reflect global pollution and that high levels in dolphins and wild tuna tissues raise particular concern, as they confirm their biomagnification up the food chain. Therefore, the ongoing PCB monitoring should focus on predatory species in particular to help us better understand PCB contamination in marine ecosystems in our efforts to protect the environment and human health.

Polystyrene nanoplastics enhance the toxicological effects of DDE in zebrafish (Danio rerio) larvae

Anthropogenic releases of plastics, persistent organic pollutants (POPs), and heavy metals can impact the environment, including aquatic ecosystems. Nanoplastics (NPs) have recently emerged as pervasive environmental pollutants that have the ability to adsorb POPs and can cause stress in organisms. Among POPs, DDT and its metabolites are ubiquitous environmental pollutants due to their long persistence. Despite the discontinued use of DDT in Europe, DDT and its metabolites (primarily p,p'-DDE) are still found at detectable levels in fish feed used in salmon aquaculture. Our study aimed to look at the individual and combined toxicity of NPs (50 mg/L polystyrene) and DDE (100 μg/L) using zebrafish larvae as a model. We found no significant morphological, cardiac, respiratory, or behavioural changes in zebrafish larvae exposed to NPs alone. Conversely, morphological, cardiac and respiratory alterations were observed in zebrafish larvae exposed to DDE and NPs + DDE. Interestingly, behavioural changes were only observed in zebrafish larvae exposed to NPs + DDE. These findings were supported by RNA-seq results, which showed that some cardiac, vascular, and immunogenic pathways were downregulated only in zebrafish larvae exposed to NPs + DDE. In summary, we found an enhanced toxicological impact of DDE when combined with NPs.

POPs concentrations in cetaceans stranded along the agricultural coastline of SE Spain show lower burdens of industrial pollutants in comparison to other Mediterranean cetaceans

Despite the Mediterranean Sea being one of the world's marine biodiversity hotspots, it is a hotspot of various environmental pollutants. This sea holds eight cetacean with resident populations whose numbers are considered to decline in the last decades and which are particularly susceptible to POPs bioaccumulation due to their peculiar characteristics. In this work, we studied blubber concentration of various OCPs and several PCBs and PBDEs congeners in cetaceans stranded in the northern coast of the Gulf of Vera (Region of Murcia, SE Spain) between 2011 and 2018. Most compounds and congeners were above the limit of detection in most samples, although some pesticides like endosulfan stereoisomers or endrin were never detected. DDT and its metabolites, PCBs and metoxychlor appear as the dominant compounds while PBDEs shows concentrations of lower magnitude. Striped dolphin was the species accounting for higher concentrations of most pollutants. There were differences in concentrations and profiles between species which could be partially explained by differences on diet and feeding behavior. We also observed differences based on life history parameters suggesting maternal transfer for most POPs, in accordance with other works. DDE/ ΣDDT ratio suggest no recent exposure to these pesticides. Despite showing lower concentrations than some previous works, PCB concentrations accounted for higher total TEQ than many studies. According to toxicity thresholds in the literature, we cannot guarantee the absence of health consequences on populations studied, especially for those caused by PCBs. These findings are of major importance considering the relevance of the study area in the conservation of Mediterranean cetaceans.

Trends of banned pesticides and PCBs in different tissues of striped dolphins (Stenella coeruleoalba) stranded in the Northwestern Mediterranean reflect changing contamination patterns

Although banned for years, organochlorine pesticides and PCBs continue to affect aquatic life, dolphins being particularly exposed. The concentrations of 31 PCB congeners, and 15 banned pesticides or metabolites were measured in 5 tissues of 68 striped dolphins stranded in the Northwestern Mediterranean coast in 2010-16. The results were compared to historical data (1988-2009) and, even though there is a slow decreasing trend, the levels in the 2010-2016 samples were still elevated based on common cetacean toxicological thresholds. A transition period in 2007-08, probably caused by a morbillivirus epizootic amplified the stranding, espacially of highly contaminated specimens. From 2010, higher proportions in parent compounds towards metabolites were observed yet again. These changing patterns were likely reflect the exposure of dolphins to the remobilization of pollutants from contaminated soils and sediments, with a prominent role of rivers. This should lead to an even slower decline of these contaminants that could last for decades, requiring new efforts to reduce their dispersal to aquatic ecosystems.

High Levels of Legacy and Emerging Contaminants in Killer Whales (Orcinus orca) from Norway, 2015 to 2017

Little is known of the movement or presence of unregulated, emerging contaminants in top predators. The aim of the present study was to conduct the first screening of legacy and emerging contaminants in multiple tissues of killer whales (Orcinus orca) from Norway and investigate tissue partitioning and maternal transfer. Blubber was collected from 8 killer whales in 2015 to 2017, in addition to muscle from 5 of the individuals, and kidney, liver, heart, and spleen from a neonate. We screened for 4 unregulated brominated flame retardants and found pentabromotoluene (PBT) and hexabromobenzene (HBB) at low levels in the blubber of all individuals (median PBT 0.091 ng/g lipid wt, median HBB 1.4 ng/g lipid wt). Levels of PBT and HBB (wet wt) were twice as high in the blubber than the muscle for each individual, confirming preferential accumulation in lipid-rich tissues. Perfluoroalkyl substances and total mercury levels were lower in the neonate than adults, suggesting less efficient maternal transfer of these substances. Polychlorinated biphenyl levels in blubber exceeded the threshold for onset of physiological effects (9 µg/g lipid wt) in 7 of the 8 whales, including the neonate. The presence of PBT and HBB in the neonate is the first evidence of maternal transfer of these unregulated contaminants in marine mammals. Our results are relevant for the continued environmental monitoring of contaminants in the Arctic. Environ Toxicol Chem 2021;40:1850-1860. © 2021 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Ryanodine Receptor Type 2: A Molecular Target for Dichlorodiphenyltrichloroethane- and Dichlorodiphenyldichloroethylene-Mediated Cardiotoxicity

Dichlorodiphenyltrichloroethane (DDT) and its metabolite dichlorodiphenyl-dichloroethylene (DDE) are ubiquitously found in the environment and linked to cardiovascular diseases-with a majority of the work focused on hypertension. Studies investigating whether DDx can interact with molecular targets on cardiac tissue to directly affect cardiac function are lacking. Therefore, we investigated whether o,p'-DDT, p,p'-DDT, o,p'-DDE, or p,p'-DDE (DDx, collectively) can directly alter the function of human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) by assessing their effect(s) on hiPSC-CMs Ca2+ dynamics. DDx (0.1-10 µM) affected hiPSC-CMs synchronous Ca2+ oscillation frequency in a concentration-dependent manner, with p,p'-DDT and p,p'-DDE also decreasing Ca2+ stores. HEK-RyR2 cells cultured under antibiotic selection to induce expression of wild-type mouse ryanodine receptor type 2 (RyR2) are used to further investigate whether DDx alters hiPSC-CMs Ca2+ dynamics through engagement with RyR2, a protein critical for cardiac muscle excitation-contraction coupling (ECC). Acute treatment with 10 µM DDx failed to induce Ca2+ release in HEK293-RyR2, whereas pretreatment with DDx (0.1-10 µM) for 12- or 24-h significantly decreased sarcoplasmic reticulum Ca2+ stores in HEK-RyR2 cells challenged with caffeine (1 mM), an RyR agonist. [3H]ryanodine-binding analysis using murine cardiac RyR2 homogenates further confirmed that all DDx isomers (10 µM) can directly engage with RyR2 to favor an open (leaky) confirmation, whereas only the DDT isomers (10 µM) modestly (≤10%) inhibited SERCA2a activity. The data demonstrate that DDx increases heart rate and depletes Ca2+ stores in human cardiomyocytes through a mechanism that impairs RyR2 function and Ca2+ dynamics.

IMPACT STATEMENT

DDT/DDE interactions with RyR2 alter cardiomyocyte Ca2+ dynamics that may contribute to adverse cardiovascular outcomes associated with exposures.

Assessment of PCDD/Fs, dioxin-like PCBs and PBDEs in Mediterranean striped dolphins

Bio-accumulation of high levels of persistent organic pollutants represent a serious conservation concern for Mediterranean marine odontocetes. In this study, blubber samples from 10 striped dolphins (Stenella coeruleoalba) stranded along the Italian coasts during 2015-2016 were analyzed. All specimens showed dl-PCBs > PBDEs ≫ PCDD/Fs. Median concentrations were 1820 ng/g l.w., 456 ng/g l.w. and 23.9 pg/g l.w., respectively. dl-PCBs accounted for 93.3% of total TEQs. PBDE concentrations suggest that the Mediterranean basin may be considered a hotspot for organobromine compounds. OCDD did not represent the greatest contributor to PCDD/Fs profile, most likely due to a change in dioxin environmental sources in the last two-three decades. Despite international regulations, the present study emphasized that POP exposure levels in Mediterranean striped dolphins have not declined significantly in recent years. Toxicological and risk assessment studies on this sentinel species may provide an early indication of potential adverse health effects on Mediterranean ecosystems.

PCB and PBDE contamination in Tursiops truncatus and Stenella frontalis, two data-deficient threatened dolphin species from the Brazilian coast

Polychlorinated biphenyls (PCB) and polybrominated diphenyl ethers (PBDE) levels were assessed in the liver and muscle of two data-deficient threatened dolphin species, the bottlenose dolphin (Tursiops truncatus, n = 4) and the Atlantic spotted dolphin (Stenella frontalis, n = 6), sampled off the Southeastern Brazilian coast. PCB concentrations were greater in liver compared to muscle, with males presenting higher concentrations than females. The three main detected PCB congeners were PCBs 138, 153 and 180. A predominance of hexachlorinated congeners was observed, followed by hepta- and penta-PCBs. For both species, Cl 3 and Cl 4 levels were higher in muscle compared to liver, while Cl 5 to Cl 8 and ∑PCBs were higher in liver. PBDE concentrations were significantly higher in Atlantic spotted dolphin muscle and liver compared to bottlenose dolphins. Similarly to PCBs, the highest PBDE concentrations were observed in males. The presence of PBDE congeners BDE-47, -100 and -99 in the muscle and liver of both species suggests the existence of a pollution source in Brazil by a penta-BDE mixture, as PBDEs have never been produced in Brazil. Interspecific PCB and PBDE profiles were very similar, which may be related to the similar characteristics of the analyzed species, mainly geographic distribution and life and feeding habits. This study furthers knowledge on environmental PCB and PBDE contamination, assisting in the establishment of dolphin population conservation strategies. In addition, this study calls into question the current threshold values established for PCBs and PBDEs, and demonstrates the lack of information and knowledge in this regard for cetaceans.

Effect of aerobic exercise intervention on DDT degradation and oxidative stress in rats

Dichlorodiphenyltrichloroethane (DDT) reportedly causes extensively acute or chronic effects to human health. Exercise can generate positive stress. We evaluated the effect of aerobic exercise on DDT degradation and oxidative stress.

Main methods: Male Wistar rats were randomly assigned into control (C), DDT without exercise training (D), and DDT plus exercise training (DE) groups. The rats were treated as follows: DDT exposure to D and DE groups at the first 2 weeks; aerobic exercise treatment only to the DE group from the 1st day until the rats are killed. DDT levels in excrements, muscle, liver, serum, and hearts were analyzed. Superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), and malondialdehyde (MDA) levels were determined. Aerobic exercise accelerated the degradation of DDT primarily to DDE due to better oxygen availability and aerobic condition and promoted the degradation of DDT. Cumulative oxidative damage of DDT and exercise led to significant decrease of SOD level. Exercise resulted in consistent increase in SOD activity. Aerobic exercise enhanced activities of CAT and GSH-Px and promoted MDA scavenging. Results suggested that exercise can accelerate adaptive responses to oxidative stress and activate antioxidant enzymes activities. Exercise can also facilitate the reduction of DDT-induced oxidative damage and promoted DDT degradation. This study strongly implicated the positive effect of exercise training on DDT-induced liver oxidative stress.

The Gulf of Ambracia's Common Bottlenose Dolphins, Tursiops truncatus: A Highly Dense and yet Threatened Population

The common bottlenose dolphin (Tursiops truncatus) is the only cetacean present in the semiclosed waters of the Gulf of Ambracia, Western Greece. This increasingly degraded coastal ecosystem hosts one of the highest observed densities in the Mediterranean Sea for this species. Photo-identification data and tissue samples collected through skin-swabbing and remote biopsy sampling techniques during boat-based surveys conducted between 2006 and 2015 in the Gulf, were used to examine bottlenose dolphin abundance, population trends, site fidelity, genetic differentiation and toxicological status. Bottlenose dolphins showed high levels of year-round site fidelity throughout the 10-year study period. Dolphin population estimates mostly fell between 130 and 170 with CVs averaging about 10%; a trend in population size over the 10 years was a decline of 1.6% per year (but this was not significant). Genetic differentiation between the bottlenose dolphins of the Gulf and their conspecifics from neighbouring populations was detected, and low genetic diversity was found among individuals sampled. In addition, pesticides where identified as factors posing a real toxicological problem for local bottlenose dolphins. Therefore, in the Gulf of Ambracia, high dolphin density does not seem to be indicative of favourable conservation status or pristine habitat.

p,p'-DDE damages spermatogenesis via phospholipid hydroperoxide glutathione peroxidase depletion and mitochondria apoptosis pathway

One, 1-dichloro-2,2-bis(p-chlorophenyl) ethylene (p,p'-DDE), the major metabolite of 2,2-bis(4-chlorophenyl)-1,1,1-trichloroethane (DDT), is a known persistent organic pollutant (POPs) and male reproductive toxicant. However, the mechanism by which p,p'-DDE exposure causes male reproductive toxicity remains unknown. The objective of this study was to elucidate some mechanisms involved in this process, including the mitochondria apoptosis pathway and the role of phospholipid hydroperoxide glutathione peroxidase (PHGPx). Puberty male SD rats were given different doses of p,p'-DDE (0, 20, 60, 100 mg/kg body weight), after the treatment, the semen quality was evaluated. Western blotting was used to detect the PHGPx protein expression. Furthermore, real-time PCR was used to analyze the genetic expression of PHGPx, Bax, Cytochrom C (Cyt C), Apaf-1, and caspase-3 in the testis. Results indicated that after the exposure, sperm malformation rate showed a significant rise compared with the control group, and meanwhile, the sperm density and sperm motility parameters were reduced to some extent in different treated groups. The mitochondria apoptosis pathway was activated. And remarkably, the expression of PHGPx protein was greatly reduced by the exposure. We conclude that p,p'-DDE can damage spermatogenesis via PHGPx depletion and mitochondria apoptosis pathway.

Assessment of the levels of polycyclic aromatic hydrocarbons and organochlorine contaminants in bottlenose dolphins (Tursiops truncatus) from the Eastern Atlantic Ocean

The concentrations of 18 polychlorinated biphenyls (PCBs), 23 organochlorine pesticides (OCPs), and 16 polycyclic aromatic hydrocarbons (PAHs) were determined in the blubber and liver of 27 bottlenose dolphins (Tursiops truncatus) stranded along the Canary Islands coasts from 1997 to 2011. DDTs (mean of 60,960 and 445 ng/g lw., respectively) and PCBs (mean of 47,168 and 628 ng/g lw., respectively) were the predominant compounds in both tissues. Among PCBs the highly chlorinated PCB 180, 153 and 138 were the predominant congeners. We found a p,p'-DDE/∑DDTs ratio of 0.87 in blubber and 0.88 in liver, which is indicative of DDT ageing. All the samples showed detectable values of any of the 16 PAH studied. Phenanthrene was the most frequently detected and at the highest concentration. According to our results, concentrations of OCPs, and especially PCBs, are still at toxicologically relevant levels in blubber of bottlenose dolphins of this geographical area.

Organochlorine contaminants in tissues of common bottlenose dolphins Tursiops truncatus from the northeastern part of the Adriatic Sea

Levels of 24 organochlorine compounds, including toxic mono-ortho PCB congeners, were determined in the organs and tissues (blubber, kidney, lung, muscle, liver, heart) of 13 common bottlenose dolphins (Tursiops truncatus) stranded between 2000 and 2005 in the northern part of the Croatian territorial waters of the Adriatic Sea. Polychlorinated biphenyls (PCBs) were found at higher concentrations in comparison with organochlorine pesticides (OCPs) in all of the analyzed tissues. Sums of six indicator congeners (Σ6PCB) constituted around 50% of the total PCB amount, while PCB-153 and PCB-138 were found to have the highest concentrations. Among the seven investigated OCPs, p,p'-DDE was found at the highest concentrations. In blubber, mean values of 22,048 and 11,310ngg(-1) wet weight were determined for ΣPCB and ΣDDT, respectively. Much lower concentrations were found in muscle samples, followed by similar concentrations in kidneys, liver and heart, while the lowest levels of organochlorine contaminants were found in lungs. The results indicate that p,p'-DDT is still being introduced in the Mediterranean region. PCB concentrations are among the highest found in this region and toxicological assessments indicate that the health of this specie is at high risk.

An assessment of contaminant concentrations in toothed whale species of the NW Iberian Peninsula: part I. Persistent organic pollutants

Concentrations and patterns of polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in the blubber of the five most common toothed whales off the Northwest Iberian Peninsula (NWIP), specifically common dolphin, long-finned pilot whale, harbour porpoise, striped dolphin and bottlenose dolphin, were investigated. The study revealed that differences in PCB and PBDE concentrations among the species are highly dependent on age and sex but also on ecological factors such as trophic level, prey type and habitat. Of the five species studied, bottlenose dolphin and harbour porpoise showed the greatest concentrations of PCBs. Both species exceed the toxic threshold of 17μgg(-1) lipid weight (PCB Aroclor equivalent) for health effects on marine mammals, for 100% and 75% of the individuals tested, respectively. Overall, the PCB and PBDE levels observed in the NWIP toothed whales were of the same order of magnitude or lower than those reported by previous studies in areas of the NE Atlantic. However, they are often higher than those for toothed whales from the southern Atlantic and Pacific Ocean.

Distributions and sources of persistent organic pollutants (aliphatic hydrocarbons, PAHs, PCBs and pesticides) in surface sediments of an industrialized urban river (Huveaune), France

Surface sediments from the Huveaune River were analyzed for n-alkanes, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), organochlorine and organophosphorous pesticides (OCs and OPs) by using gas chromatography-mass spectrometry (GC-MS). Concentrations of total alkanes ranged from 184 to 26,780 μg·kg(-1) sediment dry weight (dw) with a mean concentration of 6,126 ± 8,006 μg·kg(-1)dw, concentrations of total PAHs ranged from 572 to 4,235 μg·kg(-1)dw with a mean concentration of 1966 ± 1,104 μg·kg(-1) dw, concentrations of total PCB ranged from 2.8 to 435 μg·kg(-1)dw with a mean concentration of 148 ± 164 μg·kg(-1)dw and concentrations of total pesticides ranged from 0.07 to 1.25 μg·kg(-1)dw with a mean concentration of 1.23 ± 1.29 μg·kg(-1)dw. The spatial distribution of POPs reveals that pollutant concentration is relatively higher at the mouth of the river. The molecular indices of specific n-alkanes (CPI, NAR and TAR) and molecular indices of PAHs (Ant/(Ant+Phe), Fl/(Fl+Pyr), BaA/(BaA+Chry), IPyr/(Ipyr+BghiP)) were calculated to evaluate the possible sources of hydrocarbons. These molecular indices suggest mainly pyrolytic inputs which are markedly biogenic. All contaminant levels were also compared with Sediments Quality Guidelines (SQG) showing that the contamination levels in all stations were most of the time lower than their respective SQG. While, for PCBs, five stations (H5, H6, H7, H8 and H9) were higher than their effect range median (ERM) values which may indicate high potential toxicity of the sediment with probable adverse effects to the living biota.

Spatial variability of metallic and organic contamination of anguilliform fish in New Caledonia

New Caledonia is one of the main hot spots of biodiversity on the planet. Large amounts of contaminants are discharged into the lagoon as a result of increasing anthropogenic activities such as intense mining, urbanization, and industrialization. Concentrations of 14 trace elements and 26 persistent organic pollutants (POPs: PCBs and pesticides) were measured in the muscles of two anguilliform fish species, over a coast to barrier reef gradient in two lagoon areas differently exposed to anthropic disturbances. This study emphasizes the high trace element contamination status of anguilliform fish and also highlights slight but perceptible organic pollution. The contamination extends throughout the lagoon, from coast to barrier reef, even in areas remote from emission points. High levels of trace elements, especially those linked to mining activities (i.e., Co, Cr, Fe, Mn, and Ni), were detected in coastal sites. Furthermore, the large dispersion of most POPs throughout the entire lagoon poses the question of their potential toxicity on marine organisms from numerous habitats. Our results underline the need for long-term monitoring of various contaminants over large spatial and time scales.

Organochlorine concentrations (PCBs, DDTs, HCHs, HCB and MIREX) in delphinids stranded at the northeastern Brazil

Organochlorine compounds are highly persistent in the environment, causing bioaccumulation and biomagnification through the marine food chain. To verify the bioaccumulation pattern of DDT and its metabolites, as well as PCBs, Mirex, HCHs and HCB, samples of subcutaneous adipose tissue from 25 Guiana dolphins (Sotalia guianensis), two Fraser's dolphins (Lagenodelphis hosei), two spinner dolphins (Stenella longirostris), one spotted dolphin (Stenella frontalis), and one striped dolphin (Stenella coeruleoalba) were analyzed. The collected specimens were found stranded in northeastern Brazil between 2005 and 2011. The concentrations were reported in μg·g(-1) lip, varying from 0.02 to 17.3 for ΣPCB, from 0.003 to 5.19 for ΣDDT, from 0.005 to 0.16 for ΣHCH, from 0.002 to 0.16 for HCB, and from 0.02 to 2.38 for Mirex. The PCBs dominated the bioaccumulation pattern for both the Guiana and spinner dolphins; for the other species, DDT was the major compound. A discriminant function analysis revealed the differences in the organochlorine accumulation patterns between the Guiana dolphin (S. guianensis) and the continental shelf/oceanic dolphins (S. frontalis and S. longirostris). The results also show that the concentrations of organochlorine compounds found in the delphinids in northeastern Brazil were lower than the delphinids found in other regions of Brazil, as well as other locations worldwide with intense agroindustrial development and/or a larger population.

PCBs and DDTs in Stenella coeruleoalba dolphins from the French Mediterranean coastal environment (2007-2009): current state of contamination

Organochlorinated compounds including PolyChloroBiphenyles, Dichloro-DiphenylTrichloroethan and metabolites are determinated in Stenella coeruleoalba (n = 37) stranded on the french Mediterranean coasts from 2007 till 2009. Studies are carried out on lung, muscle, kidney, liver, and blubber. The sought-after compounds are all detected to variable levels in each tissue and organ. In general, total PCBs are the most abundant, followed by total DDTs. The concentration (in ng g(-1) of lipid weight) in blubber of S. coeruleoalba, varied from 2,052 to 158,992 for PCBs and from 1,120 to 45,779 for DDTs. The ratios DDE/tDDTs are higher than 80% in almost all samples. The overall results of this work, compared to previous studies concerning the Mediterranean Sea, seems to confirm the tendency to a decrease of the contamination by organics compounds for the cetaceans in the Western Mediterranean Sea.

Contamination by polychlorinated biphenyls (PCBs) in striped dolphins (Stenella coeruleoalba) from the Southeastern Mediterranean Sea

Concentrations of polychlorinated biphenyls (PCBs) including dioxin-like PCBs (non-ortho, PCB 77, PCB 126, and PCB 169 and mono-ortho, PCB 105, PCB 118, and PCB 156) were measured in different organs and tissues (melon, blubber, liver, kidney, lung, heart, and muscle tissue) of striped dolphins (Stenella coeruleoalba) from the Eastern Mediterranean Sea (Adriatic Sea). The mean highest levels were in blubber and melon, followed by liver, kidney, lung, heart, and muscle tissue. PCB profiles were similar in all tissues and organs being dominated by the higher chlorinated homologues (hexa-CBs, 55.8-62.1%; penta-CBs, 15.4-20.0%; and hepta-CB PCB 180, 12.7-16.5%). Major PCBs in all tissues were congeners 138 and 153 collectively accounting for 50.6-58.3% of the total PCB concentrations, followed by PCB 101, 105, 118, and 180 constituting from 27.0% to 31.0%. PCB levels were higher in adult males than in adult females. The estimated 2,3,7,8-TCDD toxic equivalents of non- and mono-ortho PCBs were much higher than the threshold level above which adverse effects have been observed in other marine mammals species, suggesting that striped dolphins in this region are at risk for toxic effects.

Organochlorine compound accumulation in delphinids from Rio de Janeiro State, southeastern Brazilian coast

The present study investigated organochlorine compound levels (PCBs, DDTs and HCB) in blubber samples of six delphinid species from Rio de Janeiro State, southeastern Brazilian coast. The species analyzed inhabit the continental shelf (one killer whale, one false killer whale, two bottlenose dolphins, three rough-toothed dolphins, and four long-beaked common dolphins) and open ocean (four Fraser's dolphins). PCBs represented the greatest proportion of the sum of all measured organochlorines (from 0.60 to 257.2 μg g(-1) lw), followed by DDTs (from 0.15 to 125.6 μg g(-1) lw), and, at last, HCB (from <DL to 2.91 μg g(-1) lw). Higher concentrations were found in species that occupy the inner continental shelf (rough-toothed dolphin), as well as in cetaceans that are known to or are suspected to prey on other marine mammals (killer whale and false killer whale, respectively). The findings have shown that organochlorine levels in delphinids from southeastern Brazilian coast are comparable to those reported in cetaceans from highly industrialized regions of the Northern Hemisphere. Organochlorine accumulation patterns among delphinids from Rio de Janeiro State were related to habitat use.

Persistent organochlorine pollutants and heavy metals in tissues of common bottlenose dolphin (Tursiops truncatus) from the Levantine Basin of the Eastern Mediterranean

DDT's, PCBs and heavy metals (HM) were measured in tissues of common bottlenose dolphins, collected along the Israeli Mediterranean coast during 2004-2006. SigmaDDT and PCBs concentrations were highest in the blubber, with a wide concentration range of 0.92-142 and 0.05-7.9 mg kg(-1) wet weight, respectively. Blubber PCBs values were an order of magnitude lower than in tissues of this and other delphinid species in the Western Mediterranea. We found relatively high DDE/SigmaDDT percentage (85-96%); a common indicator of DDT degradation, which fitted the general trend of increase in the last 20 years in the Mediterranean Sea, indicating the progressive degradation of the remnant DDT and the absence of new inputs. Concentrations of HM ranged as follows: 0.01-123 mg kg(-1) wet weight for Hg, <0.04-1.3 for Cd, 1-30 for Cu, 0.3-4 for Mn, 19-517 for Fe, 4.3-68 for Zn and 2.4-48 for Ni. These concentrations were similar to those found in specimens collected during previous years in the region, suggesting stability over time in the HM levels of the basin's food-web.

Polychlorinated biphenyls and other chlorinated organic contaminants in the tissues of Mediterranean loggerhead turtle Caretta caretta

Polychlorinated biphenyls including coplanar congeners and DDT compounds were measured in different organs and tissues (liver, kidney, lung and muscle tissue) of loggerhead turtles Caretta caretta from the eastern Mediterranean Sea. The highest levels of these compounds were found in liver (PCBs: 52.32 ng/g; DDTs: 18.27 ng/g), followed by kidney (PCBs: 19.05 ng/g; DDTs: 5.70 ng/g), lung (PCBs: 12.75 ng/g; DDTs: 3.76 ng/g ) and muscle tissue (PCBs: 4.65 ng/g; DDTs: 1.45 ng/g). PCBs revealed a profile dominated by hexa-, penta- and hepta-chlorinated congeners, while among DDTs, the compound in the greatest concentration was p,p'-DDE, (liver: 85.2%, kidney: 93.6%, lung: 86.4%, muscle tissue: 93.2%). The estimated toxic equivalents (pg TEQs/g wet wt) of non- and mono-ortho PCBs were in the range of 1.54-5.86 pg TEQs/g wet wt. Non-ortho coplanar PCB 77 accounted for more than 90% of the total TEQs leaving to mono-ortho only 2.6-6.2%.

Using multi-walled carbon nanotubes as solid phase extraction adsorbents to determine dichlorodiphenyltrichloroethane and its metabolites at trace level in water samples by high performance liquid chromatography with UV detection

Carbon nanotubes (CNTs) are a kind of new carbon-based nano-materials which have drawn great attention in many application fields. The potential of multi-walled carbon nanotubes (MWNTs) as solid-phase extraction (SPE) adsorbents for the preconcentration of environmental pollutants has been investigated in recent years. The goal of this work was to investigate the feasibility of MWNTs used as SPE adsorbents to enrich dichlorodiphenyltrichloroethane (DDT) and its metabolites including 1,1-dichloro-2,2-bis-(4'-chlorophenyl)ethane (DDD) and 1,1-dichloro-2,2-bis-(4'-chlorophenyl)ethane (DDE) at trace level which are typical persistent organic pollutants in environment. Parameters that maybe influence the extraction efficiency such as the eluent volume, sample flow rate, sample pH and the sample volume were optimized in detail. The experimental results showed the excellent linear relationship between peak area and the concentration of DDT and its metabolites over the range of 0.2-60 microg L(-1), and the precisions (RSD) were 2.3-2.5% under the optimal conditions. The detection limits of proposed method could reach 4-13 ng L(-1) based on the ratio of chromatographic signal to base line noise (S/N = 3). Satisfied results were achieved when the proposed method was applied to determine the four target compounds in realworld water samples with spiked recoveries over the range of 89.7-115.5%. All these facts indicated that MWCNTs as SPE packing materials coupled to HPLC was an excellent alternative for the routine analysis of DDT and its metabolites at trace level in environment.