Assessment of physico-chemical qualities and heavy metal concentrations of Umgeni and Umdloti Rivers in Durban,South Africa

We assessed the effects of seasonal dynamics on the physico-chemical qualities and heavy metals concentrations of the Umgeni and Umdloti Rivers in Durban, South Africa. Water samples were taken from nine different sampling points and analysed for the following parameters; temperature, pH, turbidity, electrical conductivity (EC), biological oxygen demand (BOD₅), chemical oxygen demand (COD), phosphate (PO₄ ^2?), nitrate (NO₃ ^2?), ammonium (NH₄ ⁺), sulphate (SO₄ ^2?), lead (Pb²⁺), mercury (Hg²⁺), cadmium (Cd²⁺), aluminium (Al³⁺), and copper (Cu²⁺) using standard methods. The data showed variations it terms of the seasonal fluctuations and sampling regime as follows: temperature 12–26.5 °C; pH 5.96–8.45; turbidity 0.53–18.8 NTU; EC 15.8–5180 mS m^?1; BOD₅ 0.60–7.32 mg L^?1; COD 10.5–72.9 mg L^?1; PO₄ ^2??<?500–2,460 μg L^?1; NO₃ ^2? <0.05–4.21 mg L^?1; NH₄ ⁺?<?0.5–1.22 mg L^?1; SO₄ ^2? 3.90–2,762 mg L^?1; Pb²⁺ 0.023–0.135 mg L^?1; Hg²⁺ 0.0122–0.1231 mg L^?1 Cd²⁺ 0.068–0.416 mg L^?1; Al³⁺ 0.037–1.875 mg L^?1, and Cu²⁺0.006–0.144 mg L^?1. The concentrations of most of the investigated parameters exceeded the recommended limit of the South African Guidelines and World Health Organization tolerance limits for freshwater quality. We conclude that these water bodies are potentially hazardous to public health and this highlights the need for implementation of improved management strategies of these river catchments for continued sustainability.     

UV/H2O2 oxidation of arsenic and terbuthylazine in drinking water

Arsenic is a widespread contaminant in the environment. The intake of water containing high concentrations of arsenic could have serious impact on human health, such as skin and lung cancer. In the European Union, thus, also in Italy, the arsenic limit in drinking water is 10 μg L^?1. Several water remediation treatment technologies are available for arsenic removal. For some processes, the removal efficiencies can be improved after an oxidation step. Most full-scale applications are based on conventional oxidation processes for chemical micropollutant removal. However, if water contains arsenic and refractory organic contaminants, the advanced oxidation processes could be considered. The aim of this work was to investigate the effectiveness of ultraviolet (UV) radiation alone and in combination with hydrogen peroxide for the oxidation of arsenic and terbuthylazine (TBA). The experimental tests were performed in groundwater at the laboratory scale (0.1 mg L^?1 As(III) and 10 μg L^?1 TBA). Hydrogen peroxide alone (15 mg L^?1) was ineffective on both arsenic and TBA oxidation; the 253.7-nm radiation alone did not oxidize arsenic(III), but photolyzed efficiently TBA (52 % removal yield at a UV dose of 1,200 mJ cm^?2). The UV/H₂O₂ advanced oxidation (UV dose 600–2,000 mJ cm^?2, 5–15 mg L^?1 H₂O₂) was the most effective process for the oxidation of both arsenic and TBA, with observed oxidation efficiencies of 85 and 94 %, respectively, with 5 mg L^?1 H₂O₂ and a UV dose of 2,000 mJ cm^?2.     

The use of a natural coagulant (Opuntia ficus-indica) in the removal for organic materials of textile effluents

The goal of this study was to investigate the activity of the coagulant extracted from the cactus Opuntia ficus-indica (OFI) in the process of coagulation/flocculation of textile effluents. Preliminary tests of a kaolinite suspension achieved maximum turbidity removal of 95 % using an NaCl extraction solution. Optimization assays were conducted with actual effluents using the response surface methodology (RSM) based on the Box–Behnken experimental design. The responses of the variables FeCl₃, dosage, cactus dosage, and pH in the removal of COD and turbidity from both effluents were investigated. The optimum conditions determined for jeans washing laundry effluent were the following: FeCl₃ 160 mg L^?1, cactus dosage 2.60 mg L^?1, and pH 5.0. For the fabric dyeing effluent, the optimum conditions were the following: FeCl₃ 640 mg L^?1, cactus dosage 160 mg L^?1, and pH 6.0. Investigation of the effects of the storage time and temperature of the cactus O. ficus-indica showed that coagulation efficiency was not significantly affected for storage at room temperature for up to 4 days.     

Insecticide residues in soil and water in coastal areas of vegetable production in Togo

Some common organochlorine, organophosphorus and pyrethroid insecticides were analysed in agricultural soil samples (n?=?35) and surface water and groundwater samples (n?=?25) collected from coastal areas of vegetable production in Togo. Analytical methods included solvent extraction of the insecticide residues and their subsequent quantification using GC-ECD. δ-HCH, heptachlor epoxide, 4,4-DDE, endosulphan (α, β and sulphate), lambda-cyalothrin and chlorpyrifos were found in the soil samples with concentrations that varied from non-detectable (ND) to 26.93 μg kg^?1 dry weight. For water samples, heptachlor epoxide, 2,4-DDD, 4,4-DDD, 4,4-DDE and endosulphan (α, β, and sulphate) were found at contamination levels that varied from ND to 0.116 μg L^?1. The concentration of insecticide residues detected in the water samples was below the limits set by the World Health Organization (WHO) and also by the European Union (EU), with the exception of the concentration of endosulphan sulphate at the Aného site, which was 0.116 μg L^?1.     

Nutrient baselines of Cerrado low-order streams: comparing natural and impacted sites in Central Brazil

The aquatic systems responsible for water supply in the Brazilian Federal District (FD) have been threatened by anthropogenic pressures, especially considering the expressive demographic increase in the region during the last decades. The purposes of this research were: (a) to assess the water quality in streams located in the FD by monitoring physical–chemical variables; (b) to define baselines for these variables among different ecological status categories. The 14 investigated streams were sampled between 2006 and 2009, in the dry (August–September, 2006, 2008, 2009) and rainy (March–April, 2008, 2009) seasons. All sampling sites were classified in four categories (“very impacted”, “impacted”, “in transition” and “natural”) using an adaptation of a rapid habitat assessment protocol. Differences in water quality among sites were generally well predicted in the four ecological status categories defined by the protocol, which showed a gradient in nutrient concentrations from reference sites classified as “natural” (medians: electrical conductivity?=?7.3 μS cm^?1; nitrate?=?0.040 mg L^?1; ammonium?=?0.039 mg L^?1; soluble reactive phosphorus (SRP)?=?<0.001 mg L^?1; total phosphorus (TP)?=?0.006 mg L^?1; ) to those classified as “very impacted” (medians: electrical conductivity?=?87.7 μS cm^?1; nitrate?=?0.247 mg L^?1; ammonium?=?0.219 mg L^?1; SRP?=?0.010 mg L^?1; TP?=?0.035 mg L^?1). Point sources inputs were the main factor for water quality deterioration. The nutrient baselines reported were relatively low when compared to data collected from reference areas in Brazil (e.g., São Paulo State) or temperate regions, especially for TP.     

Removing arsenic from groundwater in Cambodia using high performance iron adsorbent

In Cambodia, groundwater has been contaminated with arsenic, and purification of the water is an urgent issue. From 2010 to 2012, an international collaborative project between Japan and Cambodia for developing arsenic-removing technology from well water was conducted and supported by the foundation of New Energy and Industrial Technology Development Organization, Japan. Quality of well water was surveyed in Kandal, Prey Veng, and Kampong Cham Provinces, and a monitoring trial of the arsenic removal equipment using our patented amorphous iron (hydr)oxide adsorbent was performed. Of the 37 wells surveyed, arsenic concentration of 24 exceeded the Cambodian guideline value (50 μg L^?1), and those of 27 exceeded the WHO guideline for drinking water (10 μg L^?1). Levels of arsenic were extremely high in some wells (>1,000–6,000 μg L^?1), suggesting that arsenic pollution of groundwater is serious in these areas. Based on the survey results, 16 arsenic removal equipments were installed in six schools, three temples, two health centers, four private houses, and one commune office. Over 10 months of monitoring, the average arsenic concentrations of the treated water were between 0 and 10 μg L^?1 at four locations, 10–50 μg L^?1 at eight locations, and >50 μg L^?1 at four locations. The arsenic removal rate ranged in 83.1–99.7 %, with an average of 93.8 %, indicating that the arsenic removal equipment greatly lower the risk of arsenic exposure to the residents. Results of the field trial showed that As concentration of the treated water could be reduced to <10 µg L^?1 by managing the As removal equipment properly, suggesting that the amorphous iron (hydr)oxide adsorbent has high adsorbing capacity for As not only in the laboratory environment but also in the field condition. This is one of the succeeding As removal techniques that could reduce As concentration of water below the WHO guideline value for As in situ.     

A new four-step hierarchy method for combined assessment of groundwater quality and pollution

A new four-step hierarchy method was constructed and applied to evaluate the groundwater quality and pollution of the Dagujia River Basin. The assessment index system is divided into four types: field test indices, common inorganic chemical indices, inorganic toxicology indices, and trace organic indices. Background values of common inorganic chemical indices and inorganic toxicology indices were estimated with the cumulative-probability curve method, and the results showed that the background values of Mg²⁺ (51.1 mg L^?1), total hardness (TH) (509.4 mg L^?1), and NO₃ ^? (182.4 mg L^?1) are all higher than the corresponding grade III values of Quality Standard for Groundwater, indicating that they were poor indicators and therefore were not included in the groundwater quality assessment. The quality assessment results displayed that the field test indices were mainly classified as grade II, accounting for 60.87% of wells sampled. The indices of common inorganic chemical and inorganic toxicology were both mostly in the range of grade III, whereas the trace organic indices were predominantly classified as grade I. The variabilities and excess ratios of the indices were also calculated and evaluated. Spatial distributions showed that the groundwater with poor quality indices was mainly located in the northeast of the basin, which was well-connected with seawater intrusion. Additionally, the pollution assessment revealed that groundwater in well 44 was classified as “moderately polluted,” wells 5 and 8 were “lightly polluted,” and other wells were classified as “unpolluted.”     

An assessment of contamination of the Fusaro Lagoon (Campania Province,southern Italy) by trace metals

The Fusaro Lagoon is a shallow lagoon, located in SW Italy, largely influenced in the last decades by several anthropic impacts. The study examined the pollution status of the lagoon, during year 2011–2012 at nine sampling stations with the aim to find out proper measurements of water lagoon restoration. Concentrations of heavy metals (HMs) (aluminium [Al], barium [Ba], cadmium [Cd], copper [Cu], iron [Fe], manganese [Mn], vanadium [V] and zinc [Zn]) were examined in water, sediments and specimens of the ascidian Ciona intestinalis sp. A. Low levels of dissolved oxygen concentration were detected at many stations, with mean values of 5.2–6.4 mg L^?1. The redox potential of surface waters was also low, ?2.7 to 50.7 mV. Sediments possessed high organic matter content, 17.7–29.4 %. In sediments, the mean Zn level, 251.4 mg kg^?1, was about sixfold higher than that recorded in year 2000 (38.5 mg kg^?1) and considerably higher than that recorded in 2007 (191 mg kg^?1). The mean levels of Cd were outstandingly high, with a mean value of 70.5 mg kg^?1, about 30- and 50-fold higher than those determined in 2000 and 2007, respectively. Cadmium (Cd), Cu and nickel (Ni) appeared in excess with respect to most current guidelines, reaching significant pollution levels. C. intestinalis sp. A was detected only at few stations, with metals accumulated preferentially in the body in respect to the tunic, from 1.2 times for Zn (178 mg kg^?1) to 4.0 times for V (304 mg kg^?1). Data suggests the necessity of an immediate action of eco-compatible interventions for environmental restoration.     

Groundwater phosphorus in forage-based landscape with cow-calf operation

Forage-based cow-calf operations may have detrimental impacts on the chemical status of groundwater and streams and consequently on the ecological and environmental status of surrounding ecosystems. Assessing and controlling phosphorus (P) inputs are, thus, considered the key to reducing eutrophication and managing ecological integrity. In this paper, we monitored and evaluated P concentrations of groundwater (GW) compared to the concentration of surface water (SW) P in forage-based landscape with managed cow-calf operations for 3 years (2007–2009). Groundwater samples were collected from three landscape locations along the slope gradient (GW1 10–30 % slope, GW2 5–10 % slope, and GW3 0–5 % slope). Surface water samples were collected from the seepage area (SW 0 % slope) located at the bottom of the landscape. Of the total P collected (averaged across year) in the landscape, 62.64 % was observed from the seepage area or SW compared with 37.36 % from GW (GW1?=?8.01 %; GW2?=?10.92 %; GW3?=?18.43 %). Phosphorus in GW ranged from 0.02 to 0.20 mg L^?1 while P concentration in SW ranged from 0.25 to 0.71 mg L^?1. The 3-year average of P in GW of 0.09 mg L^?1 was lower than the recommended goal or the Florida’s numeric nutrients standards (NNS) of 0.12 mg P L^?1. The 3-year average of P concentration in SW of 0.45 mg L^?1 was about fourfold higher than the Florida’s NNS value. Results suggest that cow-calf operation in pasture-based landscape would contribute more P to SW than in the GW. The risk of GW contamination by P from animal agriculture production system is limited, while the solid forms of P subject to loss via soil erosion could be the major water quality risk from P.     

Heavy metals in the habitat and throughout the food chain of the Neotropical otter, Lontra longicaudis, in protected Mexican wetlands

Top predators like the Neotropical otter, Lontra longicaudis annectens, are usually considered good bioindicators of habitat quality. In this study, we evaluated heavy metal contamination (Hg_tot, Pb, Cd) in the riverine habitat, prey (crustaceans and fish), and otter feces in two Ramsar wetlands with contrasting upstream contamination discharges: Río Blanco and Río Caño Grande in Veracruz, Mexico, during the dry, the wet, and the nortes seasons. Most comparisons revealed no differences between sites while seasonal differences were repeatedly detected for all of the compartments. Higher concentrations of Pb during the dry season and of Cd during the wet season in otter feces mirrored differences detected in the most seasonally consumed prey. Compared with fecal methylmercury values reported for the European otter (0.25–0.75 mg kg^?1) in unprotected areas, the Hg_tot levels that we measured were lower (0.02–0.17 mg kg^?1). However, Pb (117.87 mg kg^?1) and Cd (9.14 mg kg^?1) concentrations were higher (Pb, 38.15 mg kg^?1 and Cd, 4.72 mg kg^?1) in the two Ramsar wetlands. Protected areas may shelter species, but those with water-linked diets may suffer the effect of chemicals used upstream.     

Persistence and risk assessment of spiromesifen on tomato in India: a multilocational study

Supervised field trials were conducted at four different agro-climatic locations of India to evaluate the dissipation pattern and risk assessment of spiromesifen on tomato. Spiromesifen 240 SC was sprayed on tomato at 150 and 300 g a.i.?ha^?1. Samples of tomato fruits were drawn at 0, 1, 3, 5, 7, 10 and 15 days after treatment and soil at 15 days after treatment. Quantification of residues was done on gas chromatograph–mass spectrophotometer in selective ion monitoring mode in the mass range of 271–274 (m/z). The limit of quantification of the method was found to be 0.05 mg kg^?1, while the limit of determination was 0.015 mg kg^?1. Residues were found below the LOQ of 0.05 mg kg^?1 in 10 days at both the doses of application at all the locations. Spiromesifen dissipated with a half-life of 0.93–1.38 days at the recommended rate of application and 1.04–1.34 days at the double the rate of application. Residues of spiromesifen in soil were detectable level (<0.05 mg kg^?1) after 15 days of treatment. A preharvest interval (PHI) of 1 day has been recommended on tomato on the basis of data generated under All India Network Project on Pesticide Residues. Spiromesifen 240 SC has been registered for its use on tomato by Central Insecticide Board and Registration Committee, Ministry of Agriculture, Government of India. The maximum residue limit (MRL) of spiromesifen on tomato has been fixed by Food Safety Standard Authority of India, Ministry of Health and Family Welfare, Government of India as 0.3 μg/g after its risk assessment.     

Water chemistry influences the toxicity of silver to the green-lipped mussel Perna viridis

The study determined the influence and relative importance of water chemistry parameters (pH, alkalinity, hardness) on the acute toxicity of silver to the green mussel Perna viridis. A preliminary bioassay revealed that 4 mg L^???1 of silver caused 50% mortality (LC₅₀) in 96 h for mussels placed in seawater with pH 8.5, hardness 1,872 mg L^???1, and alkalinity 172 mg L^???1. Mortality of mussels increased with decreasing pH and increasing hardness and alkalinity variables. In contrast the mortality decreased with increasing pH and decreasing hardness and alkalinity values. The water chemistry also affected the concentration of sliver in experimental seawater and bioaccumulation of silver in mussels. The results revealed that the chemical properties of seawater must be considered while conducting toxicity tests with metals like silver. The possible explanations for the influence of water chemistry on silver toxicity to P. viridis are discussed.     

Dissipation and residue behavior of mepiquat on wheat and potato field application

A modified LC-MS method for the analysis of mepiquat residue in wheat, potato, and soil was developed and validated. A hydrophilic interaction liquid chromatographic column has been successfully used to retain and separate the mepiquat. Mepiquat residue dynamics and final residues in supervised field trials at Good Agricultural Practice (GAP) conditions in wheat, potato, and soil were studied. The limits of quantification for mepiquat in all samples were all 0.007 mg kg^?1, which were lower than their maximum residue limits. At fortification levels of 0.04, 0.2, and 2 mg kg^?1 in all samples, recoveries ranged from 77.5 to 116.4 % with relative standard deviations of 0.4–7.9 % (n?=?5). The dissipation half-lives (T _1/2) of mepiquat in soil (wheat), wheat plants, soil (potato), and potato plants were 4.5–6.3, 3.0–5.6, 2.2–4.6, and 2.4–3.2 days, respectively. The final residues of mepiquat were below 0.153 mg kg^?1 in soil (wheat), 0.052–1.900 mg kg^?1 in wheat, below 0.072 mg kg^?1 in soil (potato), and below 1.173 mg kg^?1 in potato at harvest time. Moreover, pesticide risk assessment for all the detected residues was conducted. A maximum 0.0012 % of acceptable daily intake (150 mg kg^?1) for national estimated daily intake indicated low dietary risk of these products.     

A method developed for determination of heptachlor and its metabolites from pork

A new method has been developed to determine heptachlor and its metabolites heptachlor-exo-epoxide and heptachlor-endo-epoxide in pork. The pork samples were extracted with acetone–n-hexane (2:8, V:V) and cleaned up by gel permeation chromatography and florisil solid-phase extraction cartridge. The extract was then determined by gas chromatography equipped with electron capture detector (GC-ECD), followed by validation using gas chromatography–mass spectrometry (GC–MS) with negative chemical ionization. Linearity of calibration curves ranged from 0.01 to 0.5 mg L^?1, with correlation coefficients of more than 0.9980 for GC-ECD and GC–MS, respectively. At spiked concentrations of 0.01, 0.05, and 0.1 mg kg^?1, the average recovery and relative standard deviation values were 87.1–102.2 and 4.0–11.3 %, respectively. The limit of quantification for each analyte was 0.01 mg kg^?1, which satisfied the current maximum residue limit permitted in pork. Our results showed that the method developed was successfully used to determine heptachlor and heptachlor epoxide residues in real pork samples.     

Total suspended matter observation in the Pearl River estuary from in situ and MERIS data

Based on the cruise data collected in the Pearl River estuary (PRE) in May 2008, an empirical two-band model by using the ratio of R _rs at 629 and 671 nm was established to retrieve total suspended matter (TSM) concentration with the determination coefficient (R²) of 0.854, mean relative error (MRE) of 7.483%, and root-mean-square error (RMSE) of 1.295 mg L^???1. To match with medium resolution imaging spectrometer (MERIS) bands, in situ remote sensing reflectance was re-sampled to the bandwidth of 10 nm. The relationship between TSM and re-sampled R _rs at 620 nm (MERIS band 6) and 665 nm (MERIS band 7) are obtained (R² = 0.748, RMSE = 1.697 mg L^???1, MRE = 8.785%, n = 13). Additionally, to map the spatial distribution of TSM in the PRE, MERIS level_1B data were calibrated using a multiple linear regression model based on in situ R _rs. Another dataset collected in the PRE in January 2004 was used to validate the two-band model and also applied to map TSM distribution from MERIS image. The comparison between measured TSM values and modeled ones showed satisfactory results (R² = 0.753, MRE = 22.199%, and RMSE = 2.603 mg L^???1).     

Mobilization of aluminum by the acid percolates within unsaturated zone of sandstones

The area of the Black Triangle has been exposed to extreme levels of acid deposition in the twentieth century. The chemical weathering of sandstones found within the Black Triangle became well-known phenomenon. Infiltration of acid rain solutions into the sandstone represents the main input of salt components into the sandstone. The infiltrated solutions–sandstone percolates–react with sandstone matrix and previously deposited materials such as salt efflorescence. Acidic sandstone percolates pH?3.2–4.8 found at ten sites within the National Park Bohemian Switzerland contained high Al-tot (0.8–10 mg?L^?1) concentrations and high concentrations of anions SO₄ (5–66 mg?L^?1) and NO₃ (2–42 mg?L^?1). A high proportion (50–98 %) of Al-tot concentration in acid percolates was represented by toxic reactive Alⁿ⁺. Chemical equilibrium modeling indicated as the most abundant Al species Al³⁺, AlSO₄ ⁺, and AlF²⁺. The remaining 2–50 % of Al-tot concentration was present in the form of complexes with dissolved organic matter Al-org. Mobilization and transport of Al from the upper zones of sandstone causes chemical weathering and sandstone structure deterioration. The most acidic percolates contained the highest concentrations of dissolved organic material (estimated up to 42 mg?L^?1) suggesting the contribution of vegetation on sandstone weathering processes. Very low concentrations of Al-tot in springs at BSNP suggest that Al mobilized in unsaturated zone is transported deeper into the sandstone. This process of mobilization could represent a threat for the water quality small-perched aquifers.     

Application of cold-induced aggregation microextraction as a fast,simple, and organic solvent-free method for the separation and preconcentration of Se(IV) in rice and various water samples

The developed method is based on cold-induced aggregation microextraction of Se(IV) using the 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid as an extractant followed by spectrophotometry determination. The extraction of Se(IV) was performed in the presence of dithizone as the complexing agent. In this method, a very small amount of 1-butyl-3-methylimidazolium hexafluorophosphate was added to the sample solution containing Se-dithizone complex. Then, the solution was kept in a thermostated bath at 50 °C for 4 min. Subsequently, the solution was cooled in an ice bath and a cloudy solution was formed. After centrifuging, the extractant phase was analyzed using a spectrophotometric detection method. Some important parameters that might affect the extraction efficiency were optimized (HCl, 0.6 mol L^?1; dithizone, 4.0?×?10^?6 mol L^?1; ionic liquid, 100 μL). Under the optimum conditions, good linear relationship, sensitivity, and reproducibility were obtained. The limit of detection (LOD) (3S_b/m) was 1.5 μg L^?1, and the relative standard deviation (RSD) was 1.2 % for 30 μg L^?1 of Se(IV). The linear range was obtained in the range of 5–60 μg L^?1. It was satisfactory to analyze rice and various water samples.     

Determination of seventeen endocrine disruptor compounds and their spatial and seasonal distribution in Ria Formosa Lagoon (Portugal)

In spite of its outstanding ecological and touristic importance the Ria Formosa Lagoon shows signs of anthropogenic pollution. Nonetheless, until the present survey no studies had ever documented the measurement of natural and pharmaceutical estrogens (17β-estradiol, estrone, and 17α-ethynylestradiol), xenoestrogenic industrial pollutants (4-octylphenol, 4-nonylphenol, and their mono and diethoxylates and bisphenol A), phytoestrogens (formononetin, biochanin A, daidzein, genistein), and sitosterol in this area. The 17 compounds measured herein are known as endocrine disrupters (EDCs) and act over the endocrine system even in few amounts (ng L^?1–μg L^?1). Thus to conclude about the influx of EDCs in the lagoon, water samples were taken every 2 months, during 1 year (2010), in low tide at nine sites distributed along the coastline. Water samples (1 L) were preconcentrated in the Oasis HLB cartridges and cleaned in silica cartridges before their analysis by GC-MS. Data showed the ubiquitous presence of potentially hazardous amounts of estrogens (particularly of ethynylestradiol, up to 24.3 ng L^?1), nonylphenol (up to 547 ng L^?1), and sitosterol (up to 12,300 ng L^?1), mainly in summer, suggesting that the increase of the local number of inhabitants (tourists), the rise of the water temperature (up to 26 °C), and the blooming of local flora may interfere with the water quality parameters. This makes the lagoon a potential model to study. Taking into account the data, it was concluded that there are conditions for the occurrence of endocrine disruption in aquatic animals, even in areas included in the natural park of the Formosa. Besides, both the high amounts of un-ionized ammonia (up to 0.3 mg L^?1) and phosphates (up to 1.6 mg L^?1) my pose risks for local fauna and humans.     

Persistence and effect of processing on reduction of chlorantraniliprole residues on brinjal and okra fruits

Dissipation and decontamination of chlorantraniliprole (Coragen 18.5 SC) in brinjal and okra fruits were studied following field application at single and double doses of 30 and 60 g ai ha^?1, and the residues of the insecticide was estimated using LC-MS/MS. Initial residues of chlorantraniliprole at single and double doses on the fruits of brinjal were 0.72 and 1.48 mg kg^?1, while on okra fruits, the residues were 0.48 and 0.91 mg kg^?1, respectively. The residues reached below detectable level of 0.01 mg kg^?1 on the 10th day. Half-life of chlorantraniliprole at 30 and 60 g ai ha^?1 on brinjal was 1.58 and 1.80 days with the calculated waiting period of 0.69 and 2.38 days, whereas on okra, the values were 1.60 and 1.70 and 0 and 1.20 days, respectively. The extent of removal of chlorantraniliprole using simple decontaminating techniques at 2 h and 3 days after spraying was 40.99–91.37 % and 29.85–89.12 %, respectively, from brinjal fruits and 47.78–86.10 % and 41.77–86.48 %, respectively, from okra fruits.     

Quantification of PAHs and chlorinated compounds by novel solid-phase microextraction based on the arrays of tin oxide nanorods

The results of an innovative study on a new and highly efficient stationary phase based on the SnO₂ nanorods coating on fused silica have been reported in this paper. SnO₂ nanorods have been grown on fused silica fibers using a hydrothermal process. The extraction properties of the fiber were investigated using headspace solid-phase microextraction (HS-SPME) mode coupled with gas chromatography–mass spectrometry detection for 1,4-dichloro-2-nitrobenzene, biphenyl, and acenaphthene. The effect of different variables on extraction efficiency was studied simultaneously using Box–Behnken method as experimental design. The variables of interest in the HS-SPME were salt effect, adsorption temperature, extraction, and desorption time. Under optimal conditions, the calibration curves were linear up to 10²–10⁵ ng?L^?1 (R ²?>?0.998) with detection limits of 10^?3, 10^?1, and 10 ng?L^?1 for acenaphthene, biphenyl, and 1,4-dichloro-2-nitrobenzene, respectively. The relative standard deviations for single fiber and fiber to fiber were less than 9.8 and 12.5 %, respectively. The high stability of the SnO₂ nanostructure coating is proved at relatively high temperatures (up to 300 °C) with a high extraction capacity and long lifespan (more than 100 times). By applying the proposed technique, promising recoveries (93–98 %) were obtained in the analysis of environmental water samples.