Barrage fishponds,a funnel effect for metal contaminants on headwater streams

Fishponds are man-made shallow water bodies that are still little studied because of their small size. They represent high value ecosystems, both environmentally (biodiversity hotspot) and economically (fish production). They can have a high place on the hydrographic network, so their influence on water quality is of first importance for rivers and water bodies located downstream and monitored under the Water Framework Directive. These small water bodies can be a source of contaminants during draining period or an efficient buffer for pesticides. We wanted to evaluate whether these ponds could also be a remediation tool against metals by following the annual evolution of upstream/downstream flows. Cadmium, copper, lead and zinc concentrations were quantified in the dissolved phase upstream and downstream of three ponds, each one having a specific agricultural environment (traditional or organic). Metal concentration was quantified in sediments and water. For the dissolved phase, the predictive non-effect concentration was often exceeded, suggesting an environmental risk. Results highlighted also greater quantity of metals at the downstream of the pond compared to the upstream, suggesting remobilization into the ponds or direct cross-sectional contributions from the watershed (e.g. runoff from crops) or even remobilization. Regarding sediments, minimal contamination was shown but a high mineralogical variability. No buffer effect of ponds, which could reduce the risk of acute or chronic toxicity, was detected.

     

Pesticide pressure and fish farming in barrage pond in Northeastern France. Part II: residues of 13 pesticides in water, sediments, edible fish and their relationships

Residues of pesticides in fish farming productions from barrage ponds are seldom studied in spite of increasing health questionings and environmental concerns. The purpose of this study is to establish the pesticide contamination profiles of sediments and edible fish from five ponds in Northeastern France. Multi-residues method and liquid chromatography–tandem mass spectrometry analysis were used to quantify 13 pesticides (azoxystrobin, carbendazim, clomazone, diflufenican, dimethachlor, fluroxypyr, iprodion, isoproturon, mesosulfuron-methyl, metazachlor, napropamid, quizalofop and thifensulfuron-methyl). Ten sediments and 143 muscles samples were analysed, corresponding to two successive fishing campaigns (first fishing date and second fishing date (P2), about 1 year later) on five sites (noted C-0, C-25, C-45, C-75 and C-85 to express the increasing gradient of crop area). Isoproturon was present in all sediments samples (1.8–56.4 μg/kg dry weight). During P2 period, carbendazim was quantified in the fish of site C-0 (0.09?±?0.02, 0.2?±?0.1 and 0.17?±?0.06 μg/kg wet weight (ww) for roach, carp and perch, respectively). Metazachlor was only quantified in perch of the site C-25 (0.13?±?0.02 μg/kg ww). Concentrations of isoproturon were similar for the sites C-45 and C-75 with 0.4?±?0.1 and 0.75?±?0.06 μg/kg ww for carp and perch, respectively. Contamination of fish reflected generally concentrations in surroundings. Isoproturon was the most concentrated and its main source was water for perch while carp was exposed through both water and sediments, highlighting their life strategies in pond.     

Kinetic study of γ-hexabromocyclododecane orally given to laying hens (Gallus domesticus)

Introduction  

High concentrations of hexabromocyclododecane (HBCD) sometimes recorded in free-range hens' eggs are thought to be due to soil ingestion. Of the three stereoisomers of HBCD (α-, β-, and γ-HBCD), γ-HBCD is the main component in the commercial mixture, as well as in environmental matrices, whereas the isomer profile is α-dominated in biota. In fish and in mammals, this shift is thought to be due to a rapid elimination of γ-HBCD and to its bioisomerization to the more persistent α-HBCD. The aim of the current controlled study was to better understand the fate of ingested HBCD in laying hens. The isomer profile in soil being γ-dominated, excretion kinetics of γ-HBCD into egg yolk, and accumulation in liver and in abdominal fat were investigated.     

Tissue distribution and bioconcentration factors of PCDD/Fs in the liver and adipose tissue following chronic ingestion of contaminated milk in rats

The aim of this study was to determine the tissue distribution of 17 PCDD/Fs following the chronic ingestion of contaminated milk in rats and to assess the "target tissue/milk" BioConcentration Factors (BCFs) of these molecules. Contaminated milk, collected in a polluted area, has been incorporated into the diet of male rats at a low dose (31 pg I-TEQ/day/rat). For this exposure, the accumulation of PCDD/Fs in target tissues (liver and adipose tissue) was limited, the tissue concentrations stabilising between 90 and 120 days of daily intake to levels close to 3 pg/g of tissue (all tissues and molecules combined). The tissue distribution seemed to be governed by the congeners properties and by the tissue characteristics. An increase in the chlorination degree of dioxins caused a decrease in their incorporation in the adipose tissue, and consequently of the BCF values. Moreover, the distribution of dioxins between hepatocytes and adipocytes differed: unlike the liver, the quantities of dioxins in the adipose tissue were significantly (P<0.05) correlated to the quantity of tissue fat. Only in the liver, the incorporation of PCDDs seemed to be facilitated when the chlorination degree of these congeners increased, the reverse phenomenon having been observed for PCDFs. However, for the same level of chlorination, the BCFs of PCDFs were 2.4 times higher than those of PCDDs in this tissue. The absence of correlation between the quantity of dioxins and that of fat and the BCFs differences of theses congeners suggested that dioxins fixation process in the liver was selective.     

Portal absorption of 14C after ingestion of spiked milk with 14C-phenanthrene, 14C-benzo[a]pyrene or 14C-TCDD in growing pigs

Polycyclic aromatic hydrocarbons (PAHs) and dioxins are lipophilic organic pollutants occurring widely in the terrestrial environment. In order to study the PAHs and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) transfer in the food chain, pigs have been fed with milk mixed either with 14C-phenanthrene, with 14C-benzo[a]pyrene or with 14C-TCDD. The analysis of portal and arterial blood radioactivity showed that both PAHs and TCDD were absorbed with a maximum concentration at 4-6 h after milk ingestion. Then, the blood radioactivity decreased to reach background levels 24 h after milk ingestion. Furthermore, the portal and arterial blood radioactivities were higher for phenanthrene (even if the injected load was the lowest) than these of benzo[a]pyrene or these of TCDD, in agreement with their lipophilicity and water solubility difference. Main 14C absorption occurred during the 1-3 h time period after ingestion for 14C-phenanthrene and during the 3-6 h time period for 14C-benzo[a]pyrene and for 14C-TCDD. 14C portal absorption rate was high for 14C-phenanthrene (95%), it was close to 33% for 14C-benzo[a]pyrene and very low for 14C-TCDD (9%). These results indicate that the three studied molecules have a quite different behaviour during digestion and absorption. Phenanthrene is greatly absorbed and its absorption occurs via the blood system, whereas benzo[a]pyrene and TCDD are partly and weakly absorbed respectively. However these two molecules are mainly absorbed via the portal vein.     

Exposure of ruminants to persistent organic pollutants and potential of decontamination

Human activities are emitting persistent organic pollutants (POPs) to the environment. These compounds have raised concerns about the risk of transfer through the food chain via animal products. They are characterized by a strong persistence in environmental matrices and a lipophilicity which may lead to their accumulation in fat tissues. In EU Regulations (no. 1881/2006, 1259/2011), maximum acceptable levels for polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans (PCDD/Fs), and dioxin-like or nondioxin-like polychlorinated biphenyls (PCBs) in food of animal origin have been set. Transfer rates from contaminated fodder to milk have been established: for PCBs, the rate of transfer varies from 5 to 90 % and for PCDD/Fs from 1 to 40 %. The differential transfer of the compounds towards milk is related to the hydrophobicity of the pollutants and to their metabolic susceptibility. According to numerous authors, soil is the major reservoir for POPs, and its involuntary ingestion by farm animals reared outdoors may be the main cause of animal product contamination (meat, milk, or eggs). Recent studies seem to indicate that soil is a real risk matrix in terms of transfer of pollutants to the food chain. A POP crisis management is extremely difficult, since it impacts many farmers located in the contaminated area. The question arising is to know if livestock contaminated by POPs may be decontaminated and further used for their initial purpose. Recent data demonstrate that the decontamination process appear feasible and depends on initial level of contamination or the physiological status of the animals.     

Pesticide pressure and fish farming in barrage pond in Northeastern France Part I: site characterization and water quality

Purpose

Fish farming in barrage pond is a rearing system commonly used worldwide. Obtaining good water quality is essential to improve sustainability of these ecosystems, both for health of fish consumers and environmental considerations. However, ponds are often located in agricultural landscape, but few study reports impact of pesticide pressure on these ecosystems. This study characterizes five sites in Northeastern France. This work establishes an initial framework for pesticide monitoring with the aim to improve understanding of the fate of pesticides in ponds.

Methods

This framework is based on surveys indicating managements and Geographical Information System (GIS) for five ponds and their watersheds (sites: C-0, C-25, C-45, C-75 and C-85) and completes with some analysis of a large spectrum of pesticide residues in surface waters.

Results

Watersheds show a gradient of crop proportion ranging from 0% to 82% of the watershed area, mainly rapeseed, wheat, barley and maize. Ponds were representative of local Northeastern France management. Many pesticides, and also nutrients, were measured in water with concentrations varying between sites and seasons. The sum of quantified molecules ranged from 0.17 ??g/l for site C-0 (March) to 8.81 ??g/l for site C-25 (October). Concentrations of metaldehyde, quinmerac, isoproturon and bentazon were sometimes above 1 ??g/l.

Conclusions

There is a strong connection between pond and watershed, due to water supply throughout the fish production cycle. Sites with small pond/big watershed are the most exposed to acute contamination a few days after spraying because water discharges are not diluted.     

Relative bioavailability of tropical volcanic soil-bound chlordecone in laying hens (Gallus domesticus)

The former use of chlordecone (CLD) in the French West Indies has resulted in long-term pollution of soils and of food chains. CLD may be transferred into eggs of hens reared outdoors, through polluted soil ingestion. Tropical volcanic soils display variable capacities of pollutant retention: CLD is less available and more persistent in andosol than in nitisol. The impact of soil type on CLD bioavailability to hens was tested through a relative bioavailability study. The deposition of CLD in egg yolk and in abdominal fat was measured in 42 individually housed laying hens fed with diets containing graded levels of CLD from polluted andosol, nitisol, or spiked oil during 23 days. Within each ingested matrix, the concentration of CLD in yolk and in abdominal fat linearly increased with the amount of ingested CLD (P < 0.001). However, the response to andosol diets and to nitisol diets was not different from the response to oil diets (P > 0.1), indicating that CLD was equally bioavailable to laying hens, irrespective of the matrix. This suggests that the hen's gastrointestinal tract efficiently extracts CLD from the two tropical volcanic soils, regardless of their retention capacity. Thus, hens reared on polluted soils with CLD may lay contaminated eggs.     

Relative bioavailability to laying hens of indicator polychlorobiphenyls present in soil

Transfer of indicator polychlorobiphenyls (PCBs) from soil into hen eggs may occur in hens reared outdoor, which ingest significant amounts of soil. This transfer depends on the bioavailability of the ingested compounds. The impact of soil on the bioavailability of indicator PCBs was assessed by means by a relative bioavailability (RBA) trial, in which their deposition in egg yolk and in abdominal fat, in response to their ingestion through contaminated-soil and through spiked-oil were compared. A sandy soil (709 μg indicator PCBs kg⁻¹ dry matter) was collected in the vicinity of a former fire involving treated wood. Twenty-eight laying hens were individually housed and fed one of the seven experimental diets during 14 d. The seven experimental diets were an uncontaminated control diet, three diets in which contaminated soil was introduced at levels of 3%, 6% and 9% and three diets in which spiked oil was introduced to achieve similar levels and profile of contaminants. Yolk, abdominal fat and liver were collected at the end of exposure. Indicator PCBs were extracted by ASE (Accelerated Solvent Extraction) and analyzed by GC-HMRS. Within each ingested matrix, the concentration of indicator PCBs in yolk and in abdominal fat linearly increased with the amount of indicator PCB ingested (P < 0.001). Except for PCB 28, the slopes of the responses to soil and to oil could not be differentiated (P > 0.1). RBA estimates did not differ from 1 for all indicator PCBs except for PCB 28, for which it was 0.58-0.59. Measurements performed on liver confirm these conclusions.     

Effect of low continuous 99Tc intake on its absorption and metabolism in young rats

A continuous daily oral dose of (99)TcO(4)(-) (5 Bq g(-1) day(-1)) was given to young rats for 56 days. In one group the intake was continued for 98 days, while in the other the intake was stopped to facilitate the determination of biological half lives in different organs and tissues. The absorbed fraction of (99)Tc increased from 0.7 to 0.9 during the experimental period (m=0.85 sigma=0.02). The whole body retained fraction (m=0.15 sigma=0.05) indicated a storage in the tissues. The liver and kidneys showed increasing concentrations of (99)Tc until a plateau was reached after 6 and 9 weeks, then a rapid decline after the intake was stopped (half life of 6 and 5 days respectively). In hair and thyroid tissue, the accumulation of (99)Tc increased linearly then declined very slowly after the intake was stopped and did not reach a plateau during the experiment. No significant amounts of (99)Tc were detected in the muscular tissues or in the walls of the digestive tract. After the contamination period, urinary and fecal excretions fell off very quickly (1 week), but significant, though low, quantities of urinary and fecal excretions were still observed 6 weeks after stopping intake.