The well-informed recycling of organic waste to agricultural land becomes increasingly desirable in dynamic, developing regions worldwide. Pursuing locally optimal benefit-risk ratios, agro-environmental research in support of OW recycling does not focus on avoiding contamination perse, but on the control of dynamics, in soil and other environmental compartments, in order not to exceed risk thresholds. We present a series of empirical research efforts that inform decision making in regions under OW pressure on OW-contained trace contaminant fate under local conditions. Their results illustrate that the present understanding of trace elements fate allows for the ex-ante assessment of fate under specific use scenarios and local conditions, with a limited set of simplifications. A well-established set of analytical tools provides the information required by such assessments. Understanding of OW-borne organic contaminants is less advanced, but the present capacity to project fate under local conditions does allow for the approximate appreciation of risk levels, the major benefit of which is to focus subsequent research on substances of concern. Ongoing long-term field trials may critically advance our understanding of OW-borne contaminant fate in soil. Developing a reasonable capacity to assess biological contaminant fate is one of its priorities.

Among alternative tillage practices, conservation tillage (CT) is a prominent greenhouse gas (GHG) mitigation strategy advocated in wheat cultivation, largely because of its low energy consumption and minimum soil disturbance during cultural operations. This paper examines the agricultural production and GHG emission trade-off of CT vis-à-vis traditional tillage (TT) on wheat farms of Bangladesh. Using a directional distance function approach, the maximum reduction in GHG emissions was searched for within all available tillage technology options, while increasing wheat production as much as possible. The underlying institutional, technical, and other socio-economic factors determining the efficient use of CT were analyzed using a fractional regression model. The average meta-efficiency score for permanent bed planting (PBP) and strip tillage (ST) was 0.89, while that achieved using power tiller operated seeders (PTOS) is 0.87. This indicates that with the given input sets, there is potential to reduce GHG emissions by about 11% for ST and PTOS; that potential is 13% for farmers using PTOS. The largest share of TT farmers cultivate wheat at lower meta-efficiency levels (0.65–0.70) compared to that observed with farmers practicing CT (0.75–0.80). Fractional regression model estimates indicate that an optimal, timely dose of fertilizers with a balanced dose of nutrients is required to reduce GHG emissions. To develop climate smart sustainable intensification strategies in wheat cultivation, it is important to educate farmers on efficient input management and CT together. Agricultural development programs should focus on addressing heterogeneities in nutrient management in addition to tillage options within CT.

Knowledge of the ecology and at-sea distribution of migratory species like seabirds has substantially increased over the last two decades. Furthermore, an increasing number of studies have recently focused on chemical contamination of birds over their annual cycle. However, the understanding of the combined effects of spatial movements and contamination on seabirds’ life-history traits is still scarce. During winter, seabirds can use very different areas, at the large-scale. Such overwintering strategies and distribution may expose individuals to contrasting environmental stressors, including pollutants. Here, we studied the winter distribution and contamination with mercury (Hg), and their combined effects on reproduction, in a great skua (Stercorarius skua) population breeding in Bjørnøya, Svalbard. We confirmed that individuals of this specific population overwinter in three different areas of the North Atlantic, namely Africa, Europe and northwest Atlantic. The highest Hg concentrations in feathers were measured in great skuas wintering off Europe (Linear Mixed Models - mean value ± SD = 10.47 ± 3.59 μg g 1 dw), followed by skuas wintering in northwest Atlantic (8.42 ± 3.70) and off Africa (5.52 ± 1.83). Additionally, we found that female winter distribution and accumulated Hg affected the volume of their eggs (Linear Mixed Models), but not the number of laid and hatched eggs (Kruskal-Wallis tests). This study provides new insights on the contamination risks that seabirds might face according to their overwinter distribution and the possible associated carry-over effects. Mercury Reproduction Spatial ecotoxicology Biologging Carry-over effects | acceptedVersion

The Black Sea is a semi-enclosed basin subject to major anthropogenic pressures, including marine litter and plastic pollution. Due to numerous large rivers draining into the basin and a population settled along the coast, the region could accumulate significant amounts of floating litter over time. Until now, only limited field data were available, and litter quantities and distribution remained unknown. In this study, floating marine macro litter (FMML) was assessed at the regional Black Sea scale for the first time, showing relatively high litter densities across the basin that reached a weighted mean of 81.5 items/km(2). Monitoring data revealed an accumulation of floating items offshore in the eastern part of the basin, resembling on a small scale a "garbage patch', where litter items were trapped, showing elevated densities in comparison to their surrounding areas. Most of these items were made of plastic materials (ca. 96%) and included large numbers of plastic and poly-styrene fragments of small size ranges (2.5-10 cm). Harmonised field data collection through consistent and regular monitoring programmes across the region is essential to establish baselines and thresholds for large scale assessment at international level.

There are large knowledge gaps concerning environmental levels and fate of many organic pollutants, particularly for chemicals of emerging concern in tropical regions of the Global South. In this study, we investigated the levels of chlorinated paraffins (CPs) and dechloranes in air and soil in rural, suburban, and urban regions in and around Dar es Salaam, Tanzania. Samples were also collected near the city's main municipal waste dumpsite and an electronic waste (e-waste) handling facility. In passive air samples, short chain CPs (SCCPs) dominated, with an average estimated concentration of 22 ng/m3, while medium chain CPs (MCCPs) had an average estimated concentration of 9 ng/m3. The average estimated air concentration of ∑dechloranes (Dechlorane Plus (DP) + Dechlorane 602 + Dechlorane 603) was three to four orders of magnitudes lower, 2 pg/m3. In soil samples, MCCPs dominated with an average concentration of 640 ng/g dw, followed by SCCPs with an average concentration of 330 ng/g dw, and ∑dechloranes with an average concentration of 0.9 ng/g dw. In both air and soil, DP was the dominating dechlorane compound. Urban pulses were observed for CPs and dechloranes in air and soil. CPs were in addition found in elevated levels at the municipal waste dumpsite and the e-waste handling facility, while DPs were found in elevated levels at the e-waste handling facility. This suggests that waste handling sites represent important emission sources for these pollutants. Investigations into seasonal trends and environmental fate of CPs and dechloranes showed that monsoonal rain patterns play a major role in governing air concentrations and mobility, particularly for the less volatile MCCPs and dechloranes. This study is the first to report levels of CPs in air from sub-Saharan Africa, and DP, Dechlorane 602, and Dechlorane 603 in soil from sub-Saharan Africa. | publishedVersion

Poly and perfluorinated alkyl substances (PFASs) are ubiquitously detected all around the world. Herein, for the first time, concentrations of 16 selected legacy and emerging PFASs are reported for sediment and edible fish collected from the Saudi Arabian Red Sea. Mean concentrations varied from 0.57 to 2.6 μg kg−1 dry weight (dw) in sediment, 3.89–7.63 μg kg−1 dw in fish muscle, and 17.9–58.5 μg kg−1 dw in fish liver. Wastewater treatment plant effluents represented the main source of these compounds and contributed to the exposure of PFAS to biota. Perfluorooctane sulfonate (PFOS) was the most abundant compound in sediment and fish tissues analysed, comprising between 42 and 99% of the ∑16PFAS. The short chain perfluorobutanoate (PFBA) was the second most dominant compound in sediment and was detected at a maximum concentration of 0.64 μg kg−1 dw. PFAS levels and patterns differed between tissues of investigated fish species. Across all fish species, ∑16PFAS concentrations in liver were significantly higher than in muscle by a factor ranging from 3 to 7 depending on fish species and size. The PFOS replacements fluorotelomer sulfonate (6:2 FTS) and perfluorobutane sulfonate (PFBS) exhibited a bioaccumulation potential in several fish species and 6:2 FTS, was detected at a maximum concentration of 7.1 ± 3.3 μg kg−1 dw in a doublespotted queenfish (Scomberoides lysan) liver. PFBS was detected at a maximum concentration of 2.65 μg kg−1 dw in strong spine silver-biddy (Gerres longirostris) liver. The calculated dietary intake of PFOS, perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA) and perfluorohexane sulfonic acid (PFHxS) exceeded the safety threshold established by the European Food Safety Authority (EFSA) in 2020 in doublespotted queenfish muscle, indicating a potential health risk to humans consuming this fish in Jeddah, Saudi Arabia. | publishedVersion

During a 2018 retrieval cruise for abandoned snow crab (Chionoecetes opilio) pots in the Barents Sea, approximately 8600 pots abandoned 1.5 years earlier were recovered. Forty-three percent of a subsample of 1000 pots contained snow crabs, with an average of three crabs per pot. Most of the crabs were alive (~98%) and dominated by large males. Pinch injuries and limb loss were common and tended to decline with increasing crab size. Reflex testing showed that the crabs were vital (i.e. the crabs moved their legs, chelipeds and maxillipeds when stimulated), which was supported by a relatively high meat content. However, energy reserves in the digestive glands (hepatopancreas reserves) were low, indicating overall energy deficiencies. Our results indicate considerable unaccounted mortality due to self-baiting, continued catch and cannibalism. The findings demonstrate that snow crab pots which are lost or abandoned in the Barents Sea fishery maintain huge potential for ghost-fishing impacts. | publishedVersion

Increasing anthropogenic activities in the Arctic represent an enhanced threat for oil pollution in a marine environment that is already at risk from climate warming. In particular, this applies to species with free-living pelagic larvae that aggregate in surface waters and under the sea ice where hydrocarbons are likely to remain for extended periods of time due to low temperatures. We exposed the positively buoyant eggs of polar cod (Boreogadus saida), an arctic keystone species, to realistic concentrations of a crude oil water-soluble fraction (WSF), mimicking exposure of eggs aggregating under the ice to oil WSF leaking from brine channels following encapsulation in ice. Total hydrocarbon and polycyclic aromatic hydrocarbon levels were in the ng/L range, with most exposure concentrations below the limits of detection throughout the experiment for all treatments. The proportion of viable, free-swimming larvae decreased significantly with dose and showed increases in the incidence and severity of spine curvature, yolk sac alterations and a reduction in spine length. These effects are expected to compromise the motility, feeding capacity, and predator avoidance during critical early life stages for this important species. Our results imply that the viability and fitness of polar cod early life stages is significantly reduced when exposed to extremely low and environmentally realistic levels of aqueous hydrocarbons, which may have important implications for arctic food web dynamics and ecosystem functioning.

The SOLEPUR process for the treatment of pig slurry, using soil as a treatment medium, was developed in France. This process decreased the COD of pig slurry by 99,9% bound 99,9% of the phosphorus and removed approximately 80% of the nitrogen. The remaining nitrogen was oxidized in the soil into nitrate and leached out in drainage water. The process of denitrification was selected to remove nitrate from the leachate and raw pig slurry was used as an external carbon source. The field and laboratory experiments demonstrated efficient denitrification of nitrate-rich leachate at an appropriate carbon/nitrogen ratio. Although nitrite appeared during denitrification as a transient product, it was effectively removed by the en of denitrification. Depending on the C/N ratio, the process of denitrification was accomplished after between 7 and 60 days and the denitrification rate varied between 0,5 and 1 kg N/d. Although a COD/NO3--N ration of 7 : 1 was essential for efficient denitrification, a higher ration of 8,75 : 1 preferable in order to obtain a complete and rapid denitrification. Further improvements are proposed are proposed in order to optimize the denitrification process. | Le procédé SOLEPUR pour le traitement du lisier de porc utilisant le sol comme support principal d'épuration a été développé en France. Ce procédé élimine 99,9% de la DCO du lisier, piège 99,9% du phosphore et élimine environ 80% de l'azote. Le procédé de dénitrification a été choisi pour éliminer les nitrates issus des percolats et le lisier de porc a été utilisé comme source de carbone. Les essais au champ et en laboratoire démontrent l'efficacité de la dénitrification dès lors que le rapport Carbone-sur-Azote était approprié. Selon ce ratio C/N, le processus de dénitrification se déroule au cours de séquences allant de 7 à 60 jours et le taux de dénitrification varie de 0,5 à 1 kgN/jour. Un ration DCO/N-NO3 de 7:1 est indispensable au bon déroulement de la dénitrification.