A field study on residues of four insecticides used in strawberry protection

Abstract

In 1986 strawberry plots were treated with dimethoate, malathion, permethrin and cypermethrin at 80% bloom of primary flowers. In 1987 the plots were sprayed with dimethoate, malathion and permethrin at 30% bloom. Residue analysis of these insecticides on the flowers were analyzed using solvent extraction and gas liquid chromatography. Residue analysis at 0 to 18 days on flowers and fruit showed an exponential decrease. Organophosphates tended to degrade more quickly than synthetic pyrethroids. The results are discussed in the context of an integrated pest management program.     

Nanoscale materials and their use in water contaminants removal—a review

Water scarcity is being recognized as a present and future threat to human activity and as a consequence water purification technologies are gaining major attention worldwide. Nanotechnology has many successful applications in different fields but recently its application for water and wastewater treatment has emerged as a fast-developing, promising area. This review highlights the recent advances on the development of nanoscale materials and processes for treatment of surface water, groundwater and industrial wastewater that are contaminated by toxic metals, organic and inorganic compounds, bacteria and viruses. In addition, the toxic potential of engineered nanomaterials for human health and the environment will also be discussed.     

Eriophorum angustifolium and Lolium perenne metabolic adaptations to metals- and metalloids-induced anomalies in the vicinity of a chemical industrial complex

As plants constitute the foundation of the food chain, concerns have been raised about the possibility of toxic concentrations of metals and metalloids being transported from plants to the higher food chain strata. In this perspective, the use of important phytotoxicity endpoints may be of utmost significance in assessing the hazardous nature of metals and metalloids and also in developing ecological soil screening levels. The current study aimed to investigate the role of glutathione (GSH) and its associated enzymes in the metabolic adaptation of two grass species namely Eriophorum angustifolium Honck. and Lolium perenne L. to metals and metalloids stress in the vicinity of a chemical industrial complex (Estarreja, Portugal). Soil and plant samples were collected from contaminated (C) and non-contaminated (reference, R) sites, respectively, near and away from the Estarreja Chemical Complex, Portugal. Soils (from 0 to 10 and 10 to 20 cm depths) were analyzed for pH, organic carbon, and metals and metalloids concentrations. Plant samples were processed fresh for physiological and biochemical estimations, while oven-dried plant samples were used for metals and metalloids determinations following standard methodologies. Both soils and plants from the industrial area exhibited differential concentrations of major metals and metalloids including As, Cu, Hg, Pb, and Zn. In particular, L. perenne shoot displayed significantly higher and lower concentrations of Pb and As, respectively at contaminated site (vs. E. angustifolium). Irrespective of sites, L. perenne shoot exhibited significantly higher total GSH pool, oxidized glutathione (GSSG) and oxidized protein (vs. E. angustifolium). Additionally, severe damages to photosynthetic pigments, proteins, cellular membrane integrity (in terms of electrolyte leakage), and lipid peroxidation were also perceptible in L. perenne shoot. Contrarily, irrespective of the sites, activities of catalase and GSH-regenerating enzyme, GSH reductase, and GSH-metabolizing enzymes such as GSH peroxidase and GSH sulfotransferase were significantly higher in shoot of E. angustifolium. Despite the higher total GSH content, L. perenne is vulnerable to multi-metals-induced stress in comparison to E. angustifolium as depicted by increased GSH- and protein oxidation, low reactive oxygen radical-processing potential (exhibited in terms of low catalase activity) and poor GSH pool utilization efficiency (in terms of lower GSH-associated enzymes activities). The outcome of the present study may be significant for understanding vital GSH-mediated metals and metalloids tolerance mechanisms in plants as well as their unsuitability for animal consumption due to higher metals and metalloids burdens.     

Seasonal and air mass trajectory effects on dissolved organic matter of bulk deposition at a coastal town in south-western Europe

Rainwater contains a complex mixture of organic compounds which may influence climate, terrestrial and maritime ecosystems and thus human health. In this work, the characteristics of DOM of bulk deposition at a coastal town on the southwest of Europe were assessed by UV–visible and three-dimensional excitation–emission matrix fluorescence spectroscopies and by dissolved organic carbon (DOC) content. The seasonal and air mass trajectory effects on dissolved organic matter (DOM) of bulk deposition were evaluated. The absorbance at 250 nm (UV_250nm) and integrated fluorescence showed to be positively correlated with each other, and they were also positively correlated to the DOC in bulk deposition, which suggest that a constant fraction of DOM is likely to fluoresce. There was more chromophoric dissolved organic matter (CDOM) present in summer and autumn seasons than in winter and spring. Bulk deposition associated with terrestrial air masses contained a higher CDOM content than bulk deposition related to marine air masses, thus highlighting the contribution of terrestrial/anthropogenic sources.     

Accumulation of arsenic, lead, copper, and zinc, and synthesis of phytochelatins by indigenous plants of a mining impacted area

Several native plants, able to grow in an unconfined mining impacted area that is now in close vicinity with urban areas, were evaluated for their ability to accumulate heavy metals. The main soil contaminants were As, Pb, Cu, and Zn. Sampling of the rhizospheric metal polluted soil showed that Euphorbia prostrata Aiton, Parthenium incanum Kunth, and Zinnia acerosa (DC.) A. Gray were able to grow in the presence of high amounts of mixtures of these elements. The plants accumulated the metals in the above ground parts and increased the synthesis of thiol molecules. E. prostrata showed the highest capacity for accumulation of the mixture of elements (588 μg g DW^?1). Analysis of the thiol-molecules profile showed that these plants synthesized high amounts of long-chain phytochelatins, accompanied by low amounts of monothiol molecules, which may be related to their higher resistance to As and heavy metals. The three plants showed translocation factors from roots to leaves >1 for As, Pb, Cu, and Zn. Thus, by periodically removing aerial parts, these plants could be useful for the phytoremediation of semi-arid and arid mining impacted areas, in which metal hyper-accumulator plants are not able to grow.     

Potential of the microbial community present in an unimpacted beach sediment to remediate petroleum hydrocarbons

The potential of the microbial communities present in the intertidal zone of an unimpacted beach (a beach that did not suffer any significant oil spill) to degrade hydrocarbons was investigated. For that, laboratory-based microcosms (50-ml flasks) were set up with sandy beach sediment spiked with crude oil and incubated with local seawater for 15 days in the dark. Three bioremediation treatments were tested (biostimulation (BS), autochthonous bioaugmentation (AB), and combined treatment of biostimulation + bioaugmentation (BS + AB)) and the results were compared with natural attenuation (NA). Visual inspection showed clearly an oil solubility increase (confirmed by a higher hydrocarbons concentration in supernatant solutions) for all tested treatments when compared to NA. Significant degradation of the oil, shown by different profiles of petroleum hydrocarbons, was also observed for the different treatments particularly for BS + AB. Therefore, the microbial community of this unimpacted beach sediment could respond to an oil spill, degrading hydrocarbons. But to increase the natural attenuation pace, obtained results indicated that BS + AB is an appropriate approach for the bioremediation of beaches recently impacted by an oil spill. The autochthonous microbial cultures can be obtained “before” or “after” the contamination of the target site, being inoculated into the site right after it contamination.     

Partitioning, sources and variability of regional and local oxidant (OX = O3 + NO2) in a coastal rural area in the southwest of Iberian Peninsula

The purpose of this work is to investigate the behaviour and variability of oxidant levels (OX?=?NO₂?+?O₃), for the first time, in a rural coastal area in the southwest of the Iberian Peninsula, affected by several air masses types. Detailed database (built-up over the years 2008 to 2011, and containing around 500,000 data) from the Atmospheric Sounding Station “El Arenosillo” was used. The observed daily cycles of NO _x and OX were influenced by air masses coming from industrial and urban area. It can be seen that the concentration of OX is made up of a NO _x -independent ‘regional’ contribution (i.e. the O₃ background), and a linearly NO _x -dependent ‘local’ contribution from primary emissions, such as traffic. The local emission is very low in this area. Also, the regional contribution is similar to unpolluted sites and presents seasonal variation, being higher in May. However, our measurements showed that the proportion of OX in the form of NO₂ increases with the increase in NO _x concentration during the day. The higher proportion of NO₂ observed at night must be due to the conversion of NO to NO₂ by the NO?+?O₃ reaction. With regards to the source of the local NO _x -dependent contribution, it may be attributed to industrial emission, or the termolecular reaction 2NO?+?O₂?=?2NO₂, at high-NO _x levels and stagnant air during several days. Finally, we estimated the photolysis rate of NO₂, J _NO2, an important key atmospheric reaction coupled with ozone. We also present surface plots of annual variation of the daily mean NO _x and OX levels, which indicate that oxidants come from transport processes instead of local emissions associated as local photochemistry.     

Quantitative–spatial assessment of soil contamination in S. Francisco de Assis due to mining activity of the Panasqueira mine (Portugal)

Through the years, mining and beneficiation processes produces large amounts of As-rich mine wastes laid up in huge tailings and open-air impoundments (Barroca Grande and Rio tailings) that are the main source of pollution in the surrounding area once they are exposed to the weathering conditions leading to the formation of AMD and consequently to the contamination of the surrounding environments, in particularly soils. In order to investigate the environmental contamination impact on S. Francisco de Assis (village located between the two major impoundments and tailings) agricultural soils, a geochemical survey was undertaken to assess toxic metals associations, related levels and their spatial distribution, and to identify the possible contamination sources. According to the calculated contamination factor, As and Zn have a very high contamination factor giving rise to 65.4 % of samples with a moderate to high pollution degree; 34.6 % have been classified as nil to very low pollution degree. The contamination factor spatial distribution put in evidence the fact that As, Cd, Cu, Pb, and Zn soils contents, downstream Barroca Grande tailing, are increased when compared with the local Bk soils. The mechanical dispersion, due to erosion, is the main contamination source. The chemical extraction demonstrates that the trace metals distribution and accumulation in S. Francisco de Assis soils is related to sulfides, but also to amorphous or poorly crystalline iron oxide phases. The partitioning study allowed understanding the local chemical elements mobility and precipitation processes, giving rise to the contamination dispersion model of the study area. The wind and hydrological factors are responsible for the chemical elements transport mechanisms, the water being the main transporter medium and soils as one of the possible retention media.     

Phenological development stages variation versus mercury tolerance,accumulation, and allocation in salt marsh macrophytes <Emphasis Type="Italic">Triglochin maritima</Emphasis> and <Emphasis Type="Italic">Scirpus maritimus</Emphasis> prevalent in Ria de Aveiro coastal lagoon (Portugal)

Efficient and sustainable management of rapidly mounting environmental issues has been the focus of current intensive research. The present study aimed to investigate the impact of plant phenological development stage variation on mercury (Hg) tolerance, accumulation, and allocation in two salt marsh macrophytes Triglochin maritima and Scirpus maritimus prevalent in historically Hg-contaminated Ria de Aveiro coastal lagoon (Portugal). Both plant samples and the sediments vegetated by monospecific stands of T. maritima and S. maritimus were collected from reference (R) and sites with moderate (M) and high (H) Hg contamination in Laranjo bay within Ria de Aveiro lagoon. Hg tolerance, uptake, and allocation in T. maritima and S. maritimus, physico-chemical traits (pH, redox potential, and organic matter content) and Hg concentrations in sediments vegetated by these species were impacted differentially by phenological development stages variation irrespective of the Hg contamination level. In T. maritima, Hg concentration increased with increase in Hg contamination gradient where root displayed significantly higher Hg followed by rhizome and leaf maximally at H. However, in S. maritimus, the highest Hg concentration was perceptible in rhizome followed by root maximally at M. Between the two studied plant species, S. maritimus displayed higher Hg tolerance index (depicted by higher plant dry mass allocated to reproductive stage) and higher available Hg at M (during all growth stages) and H (during senescent stage) when compared to T. maritimus. Both plant species proved to be Hg excluder (low root/rhizome–leaf Hg translocation). Additionally, T. maritima also acted as Hg stabilizer while, S. maritimus as Hg accumulator. It can be inferred from the study that (a) the plant phenological development stage variations significantly influenced plant Hg sensitivity by impacting sediment chemistry, plant growth (in terms of plant dry mass), Hg accumulation, and its subsequent allocation capacity, contingent to Hg contamination gradient; (b) S. maritimus accumulated higher Hg but restricted its translocation to above-ground part using exclusion process at both M and H due to its accelerated growth during Hg-tolerant reproductive/metabolically active phenological development stage greater than its counterpart T. maritima; and (c) the studied salt marsh plants although hailed from the same C3 and monocot group did not necessarily display similar phenotypic plasticity and behavior towards Hg-contaminated scenario during their life cycle.     

Earthworm ecotoxicological assessments of pesticides used to treat seeds under tropical conditions

Ecotoxicological laboratory tests (lower-tier tests) are fundamental tools for assessing the toxicity of pesticides to soil organisms. In this study, using these tests under tropical conditions, we quantified the impact of the insecticides imidacloprid, fipronil, and thiametoxam, and the fungicides captan and carboxin + thiram, all of which are used in the chemical treatment of crop seeds, on the survival, reproduction, and behavior of Eisenia andrei (Oligochaeta). With the exception of imidacloprid, none of the pesticides tested caused mortality in E. andrei in artificial soils. The LC₅₀ of imidacloprid was estimated as 25.53 mg active ingredient kg^?1 of dry soil. Earthworm reproduction rates were reduced by imidacloprid (EC₅₀ = 4.07 mg kg^?1), fipronil (EC₂₀ = 23.16 mg kg^?1), carboxin + thiram (EC₅₀ = 56.38 mg kg^?1), captan (EC₅₀ = 334.84 mg kg^?1), and thiametoxam (EC₅₀ = 791.99 mg kg^?1). Avoidance behavior was observed in the presence of imidacloprid (AC₅₀ = 0.11 mg kg^?1), captan (AC₅₀ = 33.54 mg kg^?1), carboxin + thiram (AC₅₀ = 60.32 mg kg^?1), and thiametoxam (AC₅₀ = >20 mg kg^?1). Earthworms showed a preference for soils with the insecticide fipronil. Imidacloprid was the most toxic of the substances tested for E. andrei. The avoidance test was the most sensitive test for most pesticides studied, but results varied between pesticides. These results offer new insights on the toxicity of pesticides used to treat seeds in tropical regions. However, they should be complemented with higher-tier tests in order to reduce the uncertainties in risk assessment.