pp´DDT and pp´DDE Accumulation in a Food Chain of Lake Maggiore (Northern Italy): Testing Steady-State Condition

- DOI: http://dx.doi.org/10.1065/espr2006.01.010 Background, Aims and Scope Although pp'DDT usage was strongly limited or banned in most parts of the world during the last three or four decades, the parent compound, its homologues and their metabolites still occur at levels which might pose a risk for many ecosystem components. A case of DDT pollution of industrial origin was discovered in 1996 in Lake Maggiore, the second largest (212 km2) and deepest (370 m) lake in Italy, causing concern for wildlife and human health. The extensive monitoring of many biotic and abiotic compartments which followed from 1998 in order to assess the pollution level and its trend in time, provided a great availability of data referring to DDT contamination of the different fish species of the lake. In this study, the recent contamination levels in selected fish species were compared to those measured in 1998 to evaluate the temporal pollution trend of the lake and its natural recovery, given that no remediation measures were carried out on the contaminated soils and sediments in this time span. Moreover, a modelling approach to test the equilibrium condition between water and pelagic fish species was used. Analytical results of pp'DDT and pp'DDE concentrations in lake water were used as input data in the bioenergetic model by Connolly & Pedersen (1988) to calculate concentrations in two fish species and to compare the predicted and the measured contamination. Methods Sampling and analytical determination of DDT homologues in lake water: Five water sampling campaigns were carried out from May 2002 to February 2004 in three sampling sites of Lake Maggiore. Suspended and dissolved pollutants were determined separately. Quantitative DDT homologue analyses were performed by HRGC coupled with ECD detection by the external standard method. Single water extracts were put together in correspondence with the stratification zones of the water column inferred on the basis of the temperature profile to improve analytical sensitivity. Selection of fish data: Concentrations of DDT and DDE in fishes were selected from recent literature (CIPAIS 2003, 2004). Bioaccumulation model: The bioenergetic model proposed by Connolly & Pedersen (1988) was used to assess the bioaccumulation of pp'DDT and pp'DDE of Alosa fallax (landlocked shad) and Coregonus spp. (whitefish), selected among the different species as representative of a secondary consumer level. Results and Discussion The average concentrations of pp'DDT and pp'DDE in water to be used as input data in the bioenergetic model were obtained considering all the concentrations measured at the three sampling stations in the epylimnion where the fish species considered in this study spend most of their life. The resulting values were 0.05 and 0.16 ng/L for pp'DDT and pp'DDE, respectively. Average measured pp'DDT and pp'DDE concentrations in landlocked shad were 0.81 +/- 0.39 and 1.69 +/- 0.71 mg/kg lipids, respectively, and were 0.29 +/- 0.12 and 1.06 +/- 0.41 mg/kg lipids for the whitefish. Calculated and measured values turned out to be in quite good agreement for pp'DDT, while measured pp'DDE concentrations were higher than expected on the basis of the bioenergetic model in both species. Probably metabolic transformations of pp'DDT accumulated in fish tissues in the past are responsible for the observed differences between calculated and expected pp'DDE concentrations in fish. Conclusions Pelagic fishes of Lake Maggiore seem to maintain the DDT accumulated during their life time and the most efficient mechanism responsible for the fish population recoveries is probably their generation changes; for this reason, equilibrium models cannot be used until negligible pp'DDT concentrations are reached in fish tissues. Recommendations and Outlook The limit proposed for pp'DDT in water by the EU Directive 2000/60, which will come in force in 2008, is 0.2 ng/L, four times higher than the average concentration measured in Lake Maggiore waters. Nevertheless, concentrations measured in Lake Maggiore fish were very close and sometimes exceeded the Maximum residue limits (MRLs) settled by the Italian legislation for foods (0.1 mg/kg w.w. for fish containing 5–20% lipid). It seems, therefore, that the 'environmental quality standard' of 0.2 ng/L cannot guarantee the suitability of fish for human consumption.     

Toxicity of Heavy Metals on Scenedesmus quadricauda (Turp.) de Brébisson in Batch Cultures (7 pp)

Background Aquatic environments are often exposed to various pollutants like heavy metals that are released from industrial, agricultural and domestic wastes. Emissions of heavy metals can then enter all ecosystems and bring about severe problems in plants, especially algae depending on the concentrations of a given element. The objective of the investigation presented is to detect toxic effects due to some heavy metals in the biomass of green alga Scenedesmus quadricauda. Methods All experiments were conducted with axenic cultures of the green alga Scenedesmus quadricauda (Turp.) de Brebisson (Chlorococcales, Chlorophyta). The cultures were grown in Chu-no.10 medium, and optimum physical and chemical growth conditions were provided to get higher growth rates and lower doubling times of cells. Growth of the micro algal cultures was measured on a daily schedule by counting cultures and determination of chlorophyll-a. The sterile-filtered heavy metal concentration solutions (Cd, Pb and Cu) were prepared and added as stock solutions of their salts (CdCl2*2.5 H2O, Pb(NO3)2*H2O and CuSO4*5 H2O). Results and Discussion The growth decreased gradually with the alga exposed to Cd at 0.05, 0.1, and 0.5 mg/L in comparison with the control whereas 1 mg/L Cd2+ had a clearly destructive effect. The growth was decreased with Pb at 15, 20 and 25 mg/L gradually, while at 30 mg/L the effect was more pronounced. When Cu was used, the growth was increased gradually at 0.5, 1 and 1.5 mg/L and vice versa at 2 mg/L. Conclusion There were differences in toxic effects of the metals with different metal as well as their concentrations and the time of exposure.     

Biomarker responses in European eel (Anguilla anguilla) exposed to persistent organic pollutants. A field study in the Vaccarès lagoon (Camargue, France)

A screening of relevant biomarkers was carried out in order to evaluate metabolic and cellular damages in European eels exposed to a non-point source contamination by persistent organic pollutants (POP) such as polycyclic aromatic hydrocarbons (PAH) and organochlorine compounds (OC) in a protected area, the Nature Reserve of Camargue (France). Investigations were focused on metabolic responses including detoxification mechanisms (biotransformation, antioxidant process), energy requirements and enzymatic membrane markers either involved in neuronal conduction (acetylcholinesterase, AChE) or in osmoregulation and energy metabolism (ATPases). The hepatic and muscular glycogen rates seemed to be suitable biomarkers as well as three hepatic activities involved in the protection against oxyradicals: catalase, glutathione peroxidase (SeGPx) and superoxide dismutases (SOD). The muscle and gill ATPases as well as the muscle and brain AChE showed more significant relevance in terms of biomarkers than the biotransformation enzymes: ethoxyresorufine-O-deethylase (EROD) and uridine diphospho-glucuronyl transferase (UDPGT). However, most of these enzymatic activities depend on numerous abiotic factors, which must be taken into account in such a biomarker assessment approach. Our study provides some conclusive elements to approve the use in situ of biomarkers developed from laboratory studies. It also raises a question regarding the location of contaminant impregnation in fish organ, in relation with age, development status or mode of contamination, and its influence on biomarker response. If the relevance of membrane indicators is confirmed, this study provides an original statement of the extent of the ecotoxicological threat for the aquatic species in a protected area, due to the occurrence of POP in the cell membranes.     

A straightforward synthesis in aqueous medium of enantiomerically enriched S(-)2,2′-dihydroxy-1,1′-binaphthyl

Chiral, atropisomeric 2,2'-dihydroxy-1,1'-binaphthyl has been extensively used to direct asymmetric processes. Its key role in asymmetric catalysis has spurred efforts to synthesize it in the optically pure form, but the reported synthetic routes have a significant environmental impact. In an aqueous peroxydase-cyclodextrin system the oxidative coupling of 2-naphthol took place very rapidly in almost quantitative yield and resulted in an enantiomeric excess. This one-pot synthesis do not require any organic solvents and oxidising metal cations.     

Determination of priority pesticides in water samples combining SPE and SPME coupled to GC–MS. A case study: Suquía River basin (Argentina)

This study reports a combined method using solid phase extraction (SPE), followed by solid phase microextraction (SPME) to concentrate different pesticides, including chlorinated, organophosphorus, triazines, pyretroids and chloroacetamides, present at trace levels in water samples. Identification and quantification was carried out by gas chromatography coupled to Mass Spectrometry (GC–MS). The optimized methodology showed LOQs at ng L^?1 levels (ranging 0.2–3.5 ng L^?1) in addition to acceptable precision and robustness (recoveries ranged 63–104%, RSD from 4% to 23%), presenting a novel method to reach trace levels, similar to that obtainable using EC detector, with structural confirmation by MS during the analysis of a wide range of environmental pollutants.This method was applied to the study of temporal and spatial distribution of pesticides in the Suquía River basin (Córdoba-Argentina). As expected, highest levels of agrochemicals were observed in areas with intensive agricultural practices, being atrazine (max. = 433.9 ng L^?1), alpha-cypermetrine (max. = 121.7 ng L^?1) and endosulfan sulfate (max. = 106.7 ng L^?1) predominant. In urban areas, the prevalent pesticide was alpha-cypermethrine. These results draw attention to the need of pesticide monitoring programs in rivers, considering both urban and rural sections.     

A retrospective study on dioxins and dioxin-like polychlorinated biphenyls in milk and dairy products from the Latium region (Italy) over a 7-year study period (2011–2017)

Environmental Science and Pollution Research - This study reports the data of polychlorinated dibenzo-p-dioxins (PCDDs), -furans (PCDFs), and polychlorinated biphenyls dioxin-like (dl PCBs)...     

An Empirical, Quantitative Approach to Predict the Reactivity of Some Substituted Aromatic Compounds Towards Reactive Radical Species (Cl2-·, Br2-·, ·NO2, SO3-·, SO4-·) in Aqueous Solution (3 pp)

The Hammett approach, applied to the reaction of various classes of aromatic compounds with the radicals Cl2-*, Br2-*, *NO2, SO3-*, and SO4-* yielded good predictive models, supported by high values of the correlation coefficient r2 in the case of phenols with Cl2-* and of phenolates with *NO2 and SO3-*. Lower but statistically significant correlation coefficients could be obtained for benzoates with Cl2-*, phenolates with Br2-*, and benzoates and anisoles with SO4-*.