Feed materials - Levels and characteristic profiles of dioxins and PCBs

Dioxins (PCDD/PCDF) are toxic compounds that are ubiquitous in the environment; although present in low concentrations, they are persistent and highly toxic and they bioaccumulate in food chains. Therefore, it is very important that feed is free of these types of contaminants, because otherwise they can become a source that can negatively affect animal health and the safety of food of animal origin. The aim of the study was to comprehensively assess the concentrations of dioxins and polychlorinated biphenyls (PCBs) in a variety of feed materials available on the Polish market. In addition, characteristic profiles of congeners for given categories of feeds were investigated and defined. Approximately 95 % of the 523 samples of various feed materials tested over seven years (2013-2018 and 2022) met the requirements of European Union feed law (Commission Regulation 277/2012/EU). The highest average PCDD/PCDF/dl-PCB concentrations were found in fish oils and meal and were respectively 1.17 ± 0.78 and 5.51 ± 4.51 ng WHO-TEQ/kg of feed at 12 % moisture. Median and background level concentrations of PCDD/PCDFs, dl-PCBs, PCDD/PCDF/dl-PCBs, and ndl-PCBs were significantly lower than their average concentrations for each individual feed material category. The WHO-TEQ profiles enabled the identification of three different characteristic profiles in feed materials.

Background construction for tracing metal inputs in estuarine sediments of the Liaodong Bay (NE China): Linear-regression method

Intertidal sediments are a significant reservoir of trace metals originating from human activities and natural weathering. However, the absence of geochemical background levels and the heterogeneity of sediment components are challenging to quantify the extent of trace metal contamination. For distinguishing the contribution of natural and anthropogenic inputs, dynamic background functions were established by linear regressions of trace metals (i.e., Zn, Cr, Ni, Cu, Cd, and Pb) against normalizer Al in three cores of the Daliao River estuary. Lead-210 geochronology indicated that trace metals have accumulated rapidly in the sediments since 1985 CE. The calculation results of enrichment factors and excess fluxes confirmed that the increased contents of Zn and Cd were contaminated by human activities. Conversely, the increased contents of others (i.e., Cr, Ni, Cu, and Pb) were attributed to variations in geological background levels, driven by the combination of grain size and organic matter. Overall levels of trace metals were at medium-low ecological risks (MSQG-Q: 0.19-0.38), and Ni at high-medium ecological risks (PEL-Q_Ni > 0.5) in recent decades. Interestingly, these Ni probably originated from natural weathering rather than anthropogenic inputs because sediment quality guidelines lacked consideration for the differences in regional background levels and grain size. This procedure could provide the fundamental framework for regional investigations of spatial and temporal contamination, applied to other similar intertidal zones of sediment quality management.

Assessment of potential contamination and acid drainage generation in uranium mining zones of Peña Blanca, Chihuahua, Mexico

Potential pollution of mining environmental liabilities' locations can be preliminarily and efficiently assessed by the potential generation of acid mine drainage and indices of contamination. This research evaluates the potential pollution by potentially toxic elements at locations with uranium mining liability evidence, using the net acid generation test and determining the background values to estimate acid mine drainage and indices of contamination. Sixty soil samples were collected, and the mineralogy and potentially toxic elements' total contents were determined by x-ray diffraction and optical spectrometry. The findings suggest that the soils related to a specific lithology might not present potential acid mine drainage generation but potential soil and sediment contamination. Future research is recommended on applying leaching tests to identify which potentially toxic elements are effectively being solubilized. Finally, it can be concluded that the study area's potential contamination is relatively low overall.

Polluting potential from mining wastes: proposal for application a global contamination index

Indices of contamination (IC) are usually employed to assess the hazardousness associated with potentially toxic elements (PTE) from mining wastes (MW). For such, it is necessary to know the total concentrations of the PTE and local, regional, or global background or reference levels which are tolerable or acceptable threshold values for total content in soils. Although scientific literature is vast regarding the application of IC to MW, there is scarce research on the reference levels that must be employed in locations with no established comparison values. This study proposes basic reference levels for the global application of PTE contents in MW, leading to a global index of contamination (IC_G). To this end, it was determined that the PTE to be assessed in MW should be As, Cd, Co, Cr, Cu, Hg, Mo, Ni, Pb, Sb, Se, V, and Zn. From the analysis of background and baseline values for soils, reference values for the PTE compiled from worldwide standards or studies on soil and sediment evaluation, and PTE content in MW, a classification is proposed for IC_G that considers MW as very low, low, moderate, high, and very high contamination potential. The findings presented herein can be helpful in the comparison of multiple types of MW, representing the contamination hazard by particle emission due to erosion processes that reach the soils or sediments of the surrounding environment. This evaluation can aid in the decision-making process regarding the reutilization of some types of MW that receive a low classification.

Combining single and complex indices of pollution with grain size trend analysis of surficial sediments in Edremit Gulf, western Turkey

Pollution risk assessment of heavy metals (Pb, Cr, Cu, Ni, Zn, As) in sediment samples from 68 locations in the Gulf of Edremit, western Turkey, was performed using single and complex indices of pollution assessment approaches. The pollution indices used in the sediment analyses included pollution load index, contamination factor, contamination degree for individual metals, geoaccumulation index (Igeo), enrichment factors, toxic risk index, modified pollution index, frequency of adverse biological effects (TEL-PEL), percent incidence of biological effects (ERL-ERM), and total risk quotients. Results indicated a low degree of contamination for the entire surveyed area except moderate contamination factor for arsenic using single indices. Enrichment factors and geoaccumulation indices indicated moderate to significant enrichment and uncontaminated to moderately contaminated both for arsenic (As) and lead (Pb), respectively. According to the results of ecological risk assessment based on TELs and PELs, the adverse biological effects of heavy metals on aquatic organisms; are for As, Cr, Ni frequently, Cu and Pb occasionally, and Zn rare. The toxic risk index values displayed low to considerably toxic risk for the entire Gulf and calculated toxic risk index results showed that arsenic accounted for most of the entire sediment toxicity. Transport patterns of sediment grain size trend analyses were correlated with the results of pollution assessment models. Transport trends are compatible with the sources of lithogenic, anthropogenic, mining activities and wastewater treatment/geothermal originated arsenic.

Metal and metalloid pollution in shelf sediments from the Gulf of Cádiz (Southwest Spain): Long-lasting effects of a historical mining area

The Gulf of Cádiz is an area historically affected by acid mine drainage and also by the discharge of two important rivers, the Guadiana and the Guadalquivir. Metal and metalloid (As, Cd, Hg, Pb, Zn, Cu, Cr, Ni, Mn, Fe, Al and Li) concentrations were measured in 33 surface sediment samples, collected in the continental shelf, inside the Ría de Huelva and the Bay of Cádiz, to assess the metal pollution status of this area. Geographical distribution was identified for different groups of metals: Cu, Cd, Zn, Hg and As were mainly associated with discharges of the Tinto and Odiel rivers, which have been historically affected by mining, into the Ría de Huelva. Sediments inside this Ría presented the highest concentrations of the whole area for these metals, and enrichment factors revealed that Hg and Cu pollution spread up to 20 km away from the mouth of this Ría, into the continental shelf. On the contrary, the distribution of Ni, Cr and Mn did not show a clear gradient with distance from a pollution source, and was mainly explained by geochemical factors, such as their association with fine materials. The comparison of metal concentrations with sediment quality guidelines, predicts that adverse ecological effects due to the metal pollution may be occurring in a group of stations located in the northwest corner of the studied area. Local background levels for metals in the Gulf of Cádiz were proposed and the information obtained will be useful to identify those areas where sampling must be intensified in ongoing Marine Strategy Framework Directive (MSFD) monitoring programs. These results corroborate that metal pollution is still a serious problem in the Gulf of Cádiz.

Geochemistry of major and trace elements in surface sediments of the Saronikos Gulf (Greece): Assessment of contamination between 1999 and 2018

The Saronikos Gulf receives pressures from the most urbanized and industrialized areas in Greece, the Athens metropolitan area and Pireaus port, and as such, it is considered as a hot spot of pollution in the Eastern Mediterranean Sea. Decades after policies aiming to achieve clean seas have been introduced and implemented, it is currently relevant to evaluate their impact on the environmental quality. Here we propose a methodology for this topical issue and we assess the distribution of major and trace elements using a 20 year (1999-2018) sedimentary record, and determine the current status, as well as contamination trends. The proposed synthesis of methods is outlined by the following major steps: establishment of background levels from dated cores, calculation of Enrichment Factors (EFs) and the multi-elemental, Modified Pollution Index (MPI), and assessment of temporal trends of MPI in a sub-regional scale. Copper, Zn, and Pb exhibited the highest EFs, mostly observed in the Elefsis Bay, the Inner sector of the Gulf, and the area parallel to the western Attica coast. The MPI classified the latter areas as moderately-heavily to severely polluted. Decreasing trends were detected in the industrialized Elefsis Bay, and were attributed to the decrease of land-based metal loads. No trends were detected in the other sub-regions, highlighting the need for intensifying efforts to abate pollution by designing management plans towards the reduction of metal contamination in the Saronikos Gulf. Finally, the present study illustrates that multi, regionalized background levels are necessary for effectively resolving elemental variations, particularly in the presence of metal-rich lithological complexes within the catchment areas. This finding should be taken into account when the background levels and background assessment levels are established for the Eastern Mediterranean's sub-regional seas within the framework and implementation of the EU's Marine Strategy Framework Directive.

Prenatal exposure to legacy contaminants and visual acuity in Canadian infants: a maternal-infant research on environmental chemicals study (MIREC-ID)

BACKGROUND

Prenatal exposure to environmental contaminants can have deleterious effects on child development. While psychomotor, cognitive and behavioural outcomes have been investigated in relation to chronic exposure, the associations with visual functions remains unclear. The present study's aim was to assess the associations of prenatal exposure to legacy persistent organic pollutants and heavy metals with visual acuity in Canadian infants. The potential protective effects of selenium against mercury toxicity were also examined.

METHODS

Participants (mean corrected age = 6.6 months) were part of the Maternal-Infant Research on Environmental Chemicals (MIREC) study. Concentrations of polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), lead and mercury were measured in maternal blood during pregnancy, as well as in the cord blood. The Teller acuity card test (TAC) (n = 429) and the visual evoked potentials in a sub-group (n = 63) were used to estimate behavioural and electrophysiological visual acuity, respectively. Multivariable linear regression models were used to investigate the relationship between exposure to each contaminant and visual acuity measures, while controlling for potential confounders. Breastmilk selenium, which was available for about half of the TAC and VEP samples, was also taken into account in the mercury models as exploratory analyses.

RESULTS

We observed no significant associations between exposure to any contaminants and TAC. Analyses revealed a negative trend (p values < 0.1) between cord blood lead and mercury and electrophysiological visual acuity, whereas PCB and PBDE showed no association. When adding breastmilk selenium concentration to the mercury models, this association became statistically significant for cord concentrations (β = - 3.41, 95% CI = - 5.96,-0.86), but also for blood levels at 1st and 3rd trimesters of pregnancy (β = - 3.29, 95% CI = - 5.69,-0.88). However, further regression models suggested that this change in estimates might not be due to adjustment for selenium, but instead to a change in the study sample.

CONCLUSIONS

Our results suggest that subtle, but detectable alterations of infant electrophysiological visual acuity can be identified in a population prenatally exposed to low mercury concentrations. Compared to behavioural visual acuity testing, electrophysiological assessment may more sensitive in detecting visual neurotoxicity in relation with prenatal exposure to mercury.

Cadmium Background Levels in Groundwater in an Area Dominated by Agriculture

Cadmium is a highly toxic trace metal, which can be of geogenic or anthropogenic origin, for example, minerals, phosphate fertilizers, and combustion emissions. Due to its low sorption affinity compared to other heavy metals, Cd is easily mobilized, potentially resulting in elevated Cd concentrations in groundwater. This study assessed background levels of Cd in groundwater related to hydrogeology and hydrogeochemical processes through evaluation of a large hydrogeochemical data set composed of groundwater analyses from 6300 wells in Northwestern Germany. Calculated Cd background levels in groundwater were between 0.01 µg/L in hydrogeological units with mainly reducing conditions and 0.98 µg/L in less reducing groundwater recharge areas. The results showed that groundwater Cd concentrations above 0.5 µg/L (the German threshold value) are not necessarily elevated but could be the regional or ambient background level, depending on the hydrogeological unit. What would be considered as ambient background levels, however, indicated the influence by continuous intensive land use as well as the local geology, which is dominated by glacial deposits. Cadmium concentrations in groundwater were mainly controlled by hydrogeochemical and hydrogeological parameters and not by the amount of anthropogenic Cd input, in particular through the use of phosphate fertilizers. Instead, analyses of the solid phase revealed that Cd release from the aquifer matrix due to changes in hydrogeochemical parameters was more likely. Aquifer sediments in Northwestern Germany can be enriched in Cd originating from multiple sources, which in turn can cause elevated Cd concentrations in groundwater. Integr Environ Assess Manag 2019;00:1-11. © 2019 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals, Inc. on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Detecting long-term temporal trends in sediment-bound metals in the western Adriatic (Mediterranean Sea)

Major and trace metal concentrations were determined in western Adriatic sediment cores. Based on sediment chronology, the earliest anthropogenic influence appeared as a Zn and Pb increase in the Po River prodelta starting from ~1914. The increasing contamination signal of these trace metals propagated southward as far as 450km with a growing delay, taking ~10years to reach the south Adriatic Sea. Although greater inventories of excess trace metals in the northern sector pointed to the influence of the intense human activities in the Po River drainage basin and Venice lagoon system, we observed a reduction of excess trace metals from mid-1980s, related to the implementation of stricter environmental regulations on chemical wastewaters. In contrast, an increase in trace metal accumulation in surficial sediment from the 2000s in front of the cities of Ancona and Bari suggested a recent local input of trace metals, probably due to harbor activities.

Atmospheric tritium concentrations under influence of AREVA NC La Hague reprocessing plant (France) and background levels

In-air tritium measurements were conducted around the AREVA NC La Hague reprocessing plant, as well as on other sites that are not impacted by the nuclear industry in northwest of France. The results indicate that the dominant tritium form around the AREVA site is HT (86%). HT and HTO levels are lower than 5 and 1 Bq. m^-3 for hourly samples taken in the plume. No tritiated organic molecules (TOM) were detected. 26 measurement campaigns were performed and links were established between near-field ⁸⁵Kr, HT and HTO activities. Environmental measurements are in line with those taken at the discharge stack, and tend to demonstrate that there are no rapid changes in the tritium forms released. Out of the influence of any nuclear activities, the levels measured were below 13 mBq.m^-3 for HT and 5 mBq.m^-3 for HTO (<0.5 Bq. L^-1). HTO level in air seems to be influenced by HTO activities in surrounding seawater.

Evaluation of background soil and air polychlorinated biphenyl (PCB) concentrations on a hill at the outskirts of a metropolitan city

Air and soil sampling was conducted inside a forested area for 22 months. The sampling location is situated to the north of a metropolitan city. Average atmospheric gas and particle concentrations were found to be 180 and 28 pg m(-3) respectively, while that of soil phase was detected to be 3.2 ng g(-1) on dry matter, The congener pairs of PCB#4-10 had the highest contribution to each medium. TEQ concentration was 0.10 pg m(-3), 0.07 pg m(-3), 21.92 pg g(-1), for gas, particle and soil phases, respectively. PCB#126 and PCB#169 contributed to over 99% of the entire TEQ concentrations for each medium. Local sources were investigated by conditional probability function (CPF) and soil/air fugacity. Landfilling area and medical waste incinerator, located to the 8 km northeast, contributed to ambient concentrations, especially in terms of dioxin-like congeners. The industrial settlement (called Dilovasi being to the east southeast of 60 km distant) contributed from southeast direction. Further sources were identified by potential source contribution function (PSCF). Sources at close proximity had high contribution. Air mass transportation from Aliaga industrial region (being to the southwest of 300 km distant) moderately contributed to ambient concentrations. Low molecular weight congeners were released from soil body. 5-CBs and 6-CBs were close to equilibrium state between soil/air interfaces. PCB#171 was close to equilibrium and PCB#180 was likely to evaporate from soil, which constitute 7-CBs. PCB#199, representing 8-CBs deposited to soil. 9-CB (PCB#207) was in equilibrium between soil and air phases.

Trace metal variability in coastal waters of San Jorge Bay, Antofagasta, Chile: An environmental evaluation and statistical approach to propose local background levels

Between 2008 and 2011, twelve metals from 384 coastal waters samples from San Jorge Bay (Antofagasta, northern Chile) were collected and analyzed. The goal was to evaluate the quality of the bay's water bodies according to the current Chilean Quality Guideline and to establish background levels for these metals. The result suggests that the coastal waters of San Jorge Bay are of very good quality suitable for recreational activities involving human body contact. The natural background thresholds established for this bay were significantly lower than primary and secondary water quality guidelines. The distribution of Cu, Zn and Pb, along the bay's coastline provides evidence of the effects of industrial activity. Both situations suggest that the threshold indicated in the environmental guidelines of the Chilean legislation may be overestimated and do not represent pollution-free environments.

Background values for evaluation of heavy metal contamination in sediments in the Parnaíba River Delta estuary, NE/Brazil

This study establishes regional background levels and upper thresholds (geochemical baseline) for Zn, Cu, Pb, Cr, Mn, and Fe from surface samples and profiles taken in 16 sedimentary environments of the Parnaíba River Delta estuary, NE-Brazil. Three approaches were applied to evaluate metal contamination: normalization to Fe, statistical analysis and sediment quality guidelines or environmental assessment criteria (TEL-PEL). Metal concentrations in sediments ranged from 2.4 to 31 mg Zn kg(-1), 1.5 to 48 mg Cu kg(-1), 1.3 to 28 mg Pb kg(-1), 1.5 to 38 mg Cr kg(-1); 145 to 1,356 mg Mn kg(-1), and 0.3% to 2.5% for Fe. All metals showed positive correlations with the <0.63 μm sediment fraction, indicating a significant association with rich lithogenic sources of iron oxide-hydroxides. Results suggest a low probability of adverse effects to the local aquatic biota. The background values of the area were lower than those reported for other areas of the northeastern coast of Brazil.

Investigation of potential soil contamination with Cr and Ni in four metal finishing facilities at Asopos industrial area

The objective of this work was to investigate whether previous disposal practices in four metal finishing facilities, located at Asopos river basin (East-Central Greece), have caused any potential serious contamination of soils. The study focused mainly on Cr and Ni, which are the primary elements of concern in the area. To estimate the natural geochemical levels of Cr and Ni, thirty soil samples were collected from locations that were not suspected of any contamination. In this group of samples, Cr concentration varied between 60 and 418 mg/kg, and Ni concentrations varied from 91 to 1200 mg/kg. The second group of samples consisted of more than 100 drill cores and surface soil samples, potentially affected by the disposal of effluents and/or the drainage of runoff water from the industrial facilities. According to the findings of the study, the disposal of treated effluents in absorption type sinks resulted occasionally in the contamination of a thin layer of soil just at the bottom of the sinks, but there was no indication of downward migration, since Cr and Ni concentrations in the lower soil layers were similar to those of the reference soils.

Tritium and 14C background levels in pristine aquatic systems and their potential sources of variability

Tritium and (14)C are currently the two main radionuclides discharged by nuclear industry. Tritium integrates into and closely follows the water cycle and, as shown recently the carbon cycle, as does (14)C (Eyrolle-Boyer et al., 2014a, b). As a result, these two elements persist in both terrestrial and aquatic environments according to the recycling rates of organic matter. Although on average the organically bound tritium (OBT) activity of sediments in pristine rivers does not significantly differ today (2007-2012) from the mean tritiated water (HTO) content on record for rainwater (2.4 ± 0.6 Bq/L and 1.6 ± 0.4 Bq/L, respectively), regional differences are expected depending on the biomass inventories affected by atmospheric global fallout from nuclear testing and the recycling rate of organic matter within watersheds. The results obtained between 2007 and 2012 for (14)C show that the levels varied between 94.5 ± 1.5 and 234 ± 2.7 Bq/kg of C for the sediments in French rivers and across a slightly higher range of 199 ± 1.3 to 238 ± 3.1 Bq/kg of C for fish. This variation is most probably due to preferential uptake of some organic carbon compounds by fish restraining (14)C dilution with refractory organic carbon and/or with old carbonates both depleted in (14)C. Overall, most of these ranges of values are below the mean baseline value for the terrestrial environment (232.0 ± 1.8 Bq/kg of C in 2012, Roussel-Debet, 2014a) in relation to dilution by the carbonates and/or fossil organic carbon present in aquatic systems. This emphasises yet again the value of establishing regional baseline value ranges for these two radionuclides in order to account for palaeoclimatic and lithological variations. Besides, our results obtained from sedimentary archive investigation have confirmed the delayed contamination of aquatic sediments by tritium from the past nuclear tests atmospheric fallout, as recently demonstrated from data chronicles (Eyrolle-Boyer et al., 2014a,b). Thus Sedimentary archives can be successfully used to reconstruct past (14)C and OBT levels. Additionally, sediment repositories potentially represent significant storages of OBT that may account for in case of further remobilisation. We finally show that floods can significantly affect the OBT and (14)C levels within suspended particles or sediments depending on the origin of particles reinforcing the need to acquire baseline value range at a regional scale.