Seasonal availability and sensitivity of two field-collected mayflies for the development of a standardized toxicity test

Ecologically relevant toxicity tests may provide the best protection of sensitive aquatic fauna, but without established culturing or test methodology for such organisms, results may be unreliable and difficult to repeat. Further, field-collected organisms may not be feasible for routine testing purposes, as often required for permitted discharges. This study examined the feasibility of testing two field-collected mayflies, Isonychia bicolor and Maccaffertium spp., over a 1-year period. Seasonal comparisons of availability indicated I. bicolor and Maccaffertium spp. were most abundant during the winter months, resulting in 31 and 49 % of total organisms collected in 2009, while summer was the most difficult time to collect either species. Initial testing in January 2009 resulted in the highest no observable effect concentration (NOEC) values for survivorship (8 g NaCl for I. bicolor and 4 and 8 g NaCl/L for Maccaffertium spp.) when tested at 9°C. Subsequent tests conducted at 20–23°C resulted in 7-day NOEC values substantially lower (mean?=?1.44 and 1.59 g NaCl/L). Geometric means of exuviae indicated a dose-dependent response for I. bicolor exposed to NaCl, while no dose-dependent response was observed for Maccaffertium spp. with average number of molts varying from 4.93 in the 0.5 g NaCl/L concentration to 3.80 for control organisms followed by 2.24 (1 g NaCl/L). Averages again increased to 3.09 in the 2 g NaCl/L concentration, but declined in the highest concentrations (4–10 g NaCl/L). Based on the results of this feasibility study, field-collected mayflies appear to be too unpredictable in test responses, and therefore, such tests would be unreliable as stand-alone indicators of effluent toxicity.     

Pesticide concentrations in water and sediment and associated invertebrate toxicity in Del Puerto and Orestimba Creeks, California, 2007�C2008

The California??s San Joaquin River and its tributaries including Orestimba (ORC) and Del Puerto (DPC) Creeks are listed on the 2006 US EPA Clean Water Act §303(d) list for pesticide impairment. From December 2007 through June 2008, water and sediment samples were collected from both creeks in Stanislaus County to determine concentrations of organophosphorus (OP) and pyrethroid insecticides and to identify toxicity to Ceriodaphnia dubia and Hyalella azteca. OPs were detected in almost half (10 of 21) of the water samples, at concentrations from 0.005 to 0.912 ??g L^???1. Diazinon was the most frequently detected OP, followed by chlorpyrifos and dimethoate. Two water samples were toxic to C. dubia; based on median lethal concentrations (LC₅₀), chlorpyrifos was likely the cause of this toxicity. Pyrethroids were detected more frequently in sediment samples (18 detections) than in water samples (three detections). Pyrethroid concentrations in water samples ranged from 0.005 to 0.021 ??g L^???1. These concentrations were well below reported C. dubia LC₅₀s, and toxicity was not observed in laboratory bioassays. Cyfluthrin, bifenthrin, esfenvalerate, and ??-cyhalothrin were detected in sediment samples at concentrations ranging from 1.0 to 74.4 ng g^???1, dry weight. At DPC, all but one sediment sample caused 100% toxicity to H. azteca. Based on estimated toxicity units (TUs), bifenthrin was likely responsible for this toxicity and ??-cyhalothrin also contributed. At ORC, survival of H. azteca was significantly reduced in four of the 11 sediment samples. However, pyrethroids were detected in only two of these samples. Based on TUs, bifenthrin and ??-cyhalothrin likely contributed to the toxicity.     

Sensitivity of isolated eggs of pond snails: a new method for toxicity assays and risk assessment

The concentration of heavy metals in the environment is normally low. We here address whether using the development of isolated pond snail Radix auricularia eggs would provide a more sensitive endpoint and whether the gelatinous matrix of the egg mass surrounding the eggs indeed protects the snail embryos. In the present study, artificial removal of the gelatinous matrix of egg masses greatly increased the sensitivity of developing eggs to a heavy metal (cadmium). The sensitivity of isolated eggs to cadmium was determined using several convenient endpoints, including mortality, hatching rate, and heart rate, with an acute toxicity test and a subchronic test. In the acute toxicity test, a 96-h LC₅₀ value of 58.26 μg/L cadmium was determined. In the subchronic toxicity test, sublethal effects in terms of a significant reduction in hatching rate could be found in the 25-μg/L treatment, and a significant decrease of heart rate was observed in both treatments (5 and 25 μg/L). The high sensitivity of isolated eggs indicates that such tests can be efficient for toxicity assays and risk assessment, although one needs to keep in mind that the ecologically relevant measure of toxicity will be how eggs are affected when they are still inside the egg mass.     

Polycyclic aromatic hydrocarbon concentrations,mutagenicity, and Microtox® acute toxicity testing of Peruvian crude oil and oil-contaminated water and sediment

The oil industry is a major source of contamination in Peru, and wastewater and sediments containing oil include harmful substances that may have acute and chronic effects. This study determined polycyclic aromatic hydrocarbon (PAH) concentrations by GC/MS, mutagenicity using TA98 and TA100 bacterial strains with and without metabolic activation in the Muta-ChromoPlate? test, and Microtox® 5-min EC₅₀ values of Peruvian crude oil, and water and sediment pore water from the vicinity of San José de Saramuro on the Marañón River and Villa Trompeteros on the Corrientes River in Loreto, Peru. The highest total PAH concentration in both areas was found in water (Saramuro?=?210.15 μg/ml, Trompeteros?=?204.66 μg/ml). Total PAH concentrations in water from San José de Saramuro ranged from 9.90 to 210.15 μg/ml (mean?=?66.48 μg/ml), while sediment pore water concentrations ranged from 2.19 to 70.41 μg/ml (mean?=?24.33 μg/ml). All water samples tested from Saramuro and Trompeteros sites, and one out of four sediment pore water samples from Trompeteros, were found to be mutagenic (P?<?0.001). One sediment pore water sample in Saramuro was determined to have a measurable toxicity (Microtox EC₅₀?=?335.1 mg/l), and in Trompeteros, the EC₅₀ in water and sediment pore water ranged from 25.67 to 133.86 mg/l. Peruvian crude oil was mutagenic using the TA98 strain with metabolic activation, and the EC₅₀ was 17.18 mg/l. The two areas sampled had very high PAH concentrations that were most likely associated with oil activities, but did not lead to acute toxic effects. However, since most of the samples were mutagenic, it is thought that there is a greater potential for chronic effects.     

Histopathology alterations and lipid peroxidation as biomarkers of hydrocarbon-induced stress in earthworm, Eudrilus eugeniae

This study investigated the biomarker responses of the earthworm, Eudrilus eugeniae, exposed to sublethal concentrations of benzene, toluene and xylene (BTX) for a time span of 28 days. Lipid peroxidation (LPO) and histopathological alterations were examined. Toxicological evaluations of BTX were carried out against E. eugeniae. On the basis of the 96-h LC₅₀ value, xylene (1.212 mg/kg) was found to be the most toxic followed by toluene (1.335 mg/kg) and benzene (1.896 mg/kg) was the least toxic. The exposure of earthworms to sublethal concentrations (1/10th and 1/100th of 96 h LC₅₀) of BTX premixed with the substrate (loamy and humus soil) induced pathological changes in the clitella such as severe lesion, necrosis and dark brown pigments. The result of the lipid peroxidation assay showed a significant increase in oxidative damage with LPO values ranging from 2.58–7.8 nM/g in exposed animals when compared to 0.07 nM/g in the control group. The findings from this study suggest the use of LPO and histopathology as useful biomarkers of exposure for early detection of petroleum related stress in terrestrial ecosystems     

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.     

Acute aquatic toxicity of western juniper (Juniperus occidentalis) foliage and Port Orford cedar (Chamaecyparis lawsoniana) heartwood oils

Recently, interest has developed for using essential oils from Western juniper (Juniperus occidentalis) foliage and Port Orford cedar (Chamaecyparis lawsoniana) heartwood in commercial products such as pest repellents and cosmetics. In order to gauge the relative toxicological risk that these oils pose to freshwater and marine organisms, the acute aquatic toxicity of these oils was evaluated using OPPTS guidelines to the cladoceran Daphnia magna, the rainbow trout Oncorhynchus mykiss and the green alga Selenastrum capricornutum. For western juniper foliage oil, no toxicity was exhibited toward D. magna or O. mykiss, even at 5.0 mg/L (the highest concentration tested and limit of solubility). For toxicity to S. capricornutum using algal cell density, the 72 and 96 h EC₅₀ value was 1.7 mg/L and the no observable effect concentration (NOEC) was 0.63 mg/L. For Port Orford cedar heartwood oil, no toxicity was exhibited toward O. mykiss or S. capricornutum, even at 5.0 mg/L (the highest concentration tested and limit of solubility). The 48-h D. magna EC₅₀ value was 1.9 mg/L; the NOEC values for algal cell density were 1.25 mg/L (72 h) and 0.63 mg/L (96 h). In summary, this study shows that western juniper foliage and Port Orford cedar heartwood oils demonstrate little to no risk to aquatic organisms.     

A simple extraction procedure for determination of total mercury in crude oil

The determination of mercury in crude oil and petroleum products is particularly difficult due to the volatile nature of both mercury and the matrix, which may lead to significant loss of the analyte. A simple extraction method for total mercury has been developed to determine total mercury in crude oil using cold vapor atomic fluorescence spectrometry. The homogenized crude oil sample was diluted to 5, 10, and 20 % (w/w) in toluene. The diluted crude oil samples were spiked with 10 and 40 μg/kg (w/w). The samples were extracted using an oxidant/acid solution, BrCl/HCl. The mercury was extracted into the aqueous phase; the ionic mercury was then reduced to volatile elemental mercury (Hg⁰) by stannous chloride (SnCl₂). The mercury vapor was detected by Merlin cold vapor atomic fluorescence spectrometry at a 253.7-nm wavelength. The average recoveries for mercury in spiked diluted crude oil (10 and 40 μg/kg, w/w) were between 96 and 103 %, respectively, in 5 and 10 % spiked diluted crude oil. Whereas, low recoveries (<50 %) were recorded in 20 % diluted spiked crude oil. The method detection limit was calculated as t _{(0.01)(n ? 1)}?×?SD where t is the student's value for 99 % confidence level and standard deviation estimate with n???1 degrees of freedom. The method detection limit was found to be 0.38 μg/kg based on 5 g of diluted crude oil sample. The method is sensitive enough to determine low levels of mercury in crude oil.     

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.     

Effects of aqueous suspensions of titanium dioxide nanoparticles on Artemia salina: assessment of nanoparticle aggregation, accumulation, and toxicity

Aquatic stability and impact of titanium dioxide nanoparticles (TiO₂ NPs, 10–30 nm) were investigated using Artemia salina. Acute exposure was conducted on nauplii (larvae) and adults in seawater in a concentration range from 10 to 100 mg/L TiO₂ NPs for 24 and 96 h. Rapid aggregation occurred in all suspensions of TiO₂ NPs to form micrometer size particles. Yet, both nauplii and adults accumulated the aggregates significantly. Average TiO₂ content in nauplii ranged from 0.47 to 3.19 and from 1.29 to 4.43 mg/g in 24 and 96 h, respectively. Accumulation in adults was higher ranging from 2.30 to 4.19 and from 4.38 to 6.20 mg/g in 24 and 96 h, respectively. Phase contrast microscopy images revealed that Artemia were unable to excrete the particles. Thus, the TiO₂ aggregates filled inside the guts. No significant mortality or toxicity occurred within 24 h at any dose. Lipid peroxidation levels characterized with malondialdehyde concentrations were not statistically different from those of the controls (p?>?0.05). These results suggested that suspensions of the TiO₂ NPs were nontoxic to Artemia, most likely due to the formation of benign TiO₂ aggregates in water. In contrast, both mortality and lipid peroxidation increased in extended exposure to 96 h. Highest mortality occurred in 100 mg/L TiO₂ NP suspensions; 18 % for nauplii and 14 % for adults (LC₅₀?>?100 mg/L). These effects were attributed to the particle loading inside the guts leading to oxidative stress as a result of impaired food uptake for a long period of time.     

Characterization of fluoride-tolerant halophilic Bacillus flexus NM25 (HQ875778) isolated from fluoride-affected soil in Birbhum District, West Bengal, India

A new Gram-positive, nonpigmented, rod-shaped fluoride-tolerant bacterial strain, NM25, was isolated from waterlogged muddy field soil collected from the fluoride endemic area of Rampurhat II block (average fluoride in water, 4.7 mg/l, and in soil, 1.5 mg/kg) in Birbhum District, West Bengal, India. The study was undertaken to characterize the fluoride-tolerant bacterial isolate, to determine its role in bioaccumulation of fluoride, and to analyze the water and soil quality of the bacterial environment. The isolate was positive for catalase, lipase, urease, protease, oxidase, and H₂S production, but negative for indole production, nitrate reduction, and Vogues–Proskauer test. The organisms were sensitive to recommended doses of ofloxacin, kanamycin, rifampicin, levofloxacin, vancomycin, gatifloxacin, gentamicin, doxycycline, streptomycin, and nalidixic acid but resistant to ampicillin. Based on the phenotypic characteristics, 16S rRNA gene sequence, and phylogenetic analysis, the bacterial isolate NM25 was identified as Bacillus flexus. The G+C content of the 16S rDNA was 53.14 mol%. This strain tolerated up to 20 % (w/v) NaCl in nutrient agar medium and was grown at the pH range 4–12. It reduced fluoride concentration up to 67.45 % and tolerated more than 1,500 ppm of fluoride in brain–heart infusion agar medium.     

Organismic-level acute toxicology profiling of reactive azo dyes

In the present study, organismic-level acute toxicology profile of three reactive azo dyes, viz. Reactive Blue 221, Reactive Red 195, and Reactive Yellow 145, was investigated, by using bacterial (Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, Listeria monocytogenes, and Bacillus subtilis), fungal (Trichoderma asperellum, Aspergillus flavus, Fusarium fujikuroi, and Rhizoctonia solani), plant (Raphanus sativus, Triticum aestivum, Sorghum bicolor, and Phaseolus mungo), and aquatic (Artemia salina and Daphnia magna) specimens. Microbial test organisms (all the six bacteria and two fungi, i.e., T. asperellum and A. flavus) and D. magna were found to be relatively more sensitive towards the reactive azo dyes and their mixture, as the EC50 values were in the range of 80–330, 135–360, and 108–242 ppm for bacteria, fungi, and D. magna, respectively (but the effect was not acutely toxic). Moreover, the effect of dye mixture was comparable tothe individual dyes in almost all the tested microbial specimens. For plant seeds, the dye mixture was found to be relatively more inhibitory towards T. aestivum and R. sativus than the individual dyes. For S. bicolor and P. mungo seeds, the effect of the dye mixture was almost identical to the individual dyes. However, in all cases, EC50 values were in the range of 950–3500 ppm, which indicates a non-toxic effect on plant seed germination potential. Likewise, the dyes and their mixture were not acutely toxic for Artemia salina larvae (more sensitive to the dye mixture) and Daphnia magna neonates (EC50, 516–950 and 108–242 ppm, respectively).     

The importance of adult Hediste (Nereis) diversicolor in managing heavy metal pollution in shores and estuaries

The main aim of the toxicity test is to be able to measure toxicity in organisms, and therefore to assess whether a nationally or internationally preset standard is met. LC₅₀ values (median lethal concentration that kills 50% of the population at a given time) or LT₅₀ values (median lethal time in which 50% of the test species died) provide useful information for risk assessment. However, extrapolating laboratory data to actual field conditions is difficult because of changing environmental factors like temperature and salinity. LC₅₀ copper data for Hediste diversicolor treated multifactorially show the plasticity of the worm to environmental variables. Increasing temperature, 12 to 22°C, and increasing salinity, 7.6 to 30.5 reduced toxicity of copper to the worms without sediment. In the presence of sediment increasing temperature and increasing salinity increased toxicity of copper to the worms.     

Physicochemical properties and mineral contents of seven different date fruit (Phoenix dactylifera L.) varieties growing from Saudi Arabia

The date (Phoenix dactylifera L.) fruits (Soukari, Soulag, Barhi, Khulas, Rozaiz, Soughi and Monaif) were evaluated with respect to some physical and chemical properties. While crude protein contents of fruits change between 1.51 % (Soulag) to 2.41 % (Soughi), crude fibre contents ranged between 1.91 % (Soukari) to 3.90 % (Barhi). Vitamin C contents of date samples changed between 971.82 mg/kg (Soughi) to 1,453.15 mg/kg (Barhi). Antioxidant activity of date fruits ranged from 80.07 IC₅₀ (Soukari) to 81.21 IC₅₀ (Soulag). The highest phenolic content was found in Khulas with a mean value of 198 mg GAE/100 g. Energy values of date fruits ranged from 3,725 kcal/kg (Soulag) to 3,870 kcal/kg (Soukari). Sucrose contents of date fruits changed between 1.02 % (Soulag) to 55.71 % (Soukari). Mineral contents of several date fruits were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES). Date samples contain potassium at a range between 7,468 mg/kg (Khulas) to 9,619 mg/kg (Soulag). Phosphorus contents of fruits were found between 1,848 mg/kg (Soulag) to 3,066 mg/kg (Rozaiz) and followed by magnesium and calcium. The highest Zn (9.33 mg/kg), Cu (4.27 mg/kg) and Mn (3.26 mg/kg) were found in Rozaiz, Soukari and Barhi samples, respectively.     

Toxicity of Hg, Cu and Zn on early developmental stages of the European clam (Ruditapes decussatus) with potential application in marine water quality assessment

The toxicity of mercury, zinc and copper on sperm viability, fertilisation and embryogenesis of Ruditapes decussatus was examined. Cu did not affect sperm viability at all the concentrations tested. Conversely, the Zn and Hg significantly (P?<?0.01) reduced sperm viability only at the highest concentration (respectively 512 and 256 μg/l). Cu caused a significant decrease (p?<?0.05) of less than 6% in the fertilisation rate at 128 μg/l and Zn of up to 13% at 64 μg/l. Hg significantly (p?<?0.01) inhibited fertilisation at concentrations as low as 32 μg/l. The median effective concentrations (EC50) reducing rates of embryogenesis by 50% were 21.1 μg Hg/l (0.1 μM), 46.3 μg Cu/l (0.72 μM) and 43.4 μg Zn/l. Therefore, Hg is up to seven times more toxic than Cu (on a molar basis). Ecotoxicity of mercury on larvae survival was also assessed in this work. Result showed a significant (p?<?0.05) reduction of survival after exposure to 4 and 12 μg/l of Hg. The fertilisation rate and embryogenesis were the most sensitive endpoints, although the latter is more advisable for routine assessment of seawater quality because of its greater sensibility.     

Dynamic Modeling of Biological Treatment of Leachates from Solid Wastes

Leachates from municipal solid wastes are liquids formed by organic and inorganic components suitable for biological treatment. In biological treatment plants, prediction of the output parameter value due to dynamic variation is essential. A dynamic model based on ASM1 has been applied for prediction of effluent COD value at real scale, using three different composition leachates. Tuning between dynamic variables and predicted parameter is tested for a correct proposal of the model. Dynamic model predicts correctly fluctuations in the output COD value and tempers dynamism caused by variation of temperature and biomass concentration in the case of high organic loaded leachates. Kinetic parameters Y _H and K _s are fixed to solve the model, and dynamic variables μ _H and X_BH are changing in time. μ_H,max is obtained in simulation (0.37–1.82 day^?1) for minimum error between predicted values and experimental data. μ_H,max value is much lower compared with the value for domestic wastewater treatment due to lower biodegradability of leachate.     

Hazard assessment of metals in invasive fish species of the Yamuna River,India in relation to bioaccumulation factor and exposure concentration for human health implications

Monitoring of heavy metals was conducted in the Yamuna River considering bioaccumulation factor, exposure concentration, and human health implications which showed contamination levels of copper (Cu), lead (Pb), nickel (Ni), and chromium (Cr) and their dispersion patterns along the river. Largest concentration of Pb in river water was 392 μg L^?1; Cu was 392 μg L^?1 at the extreme downstream, Allahabad and Ni was 146 μg L^?1 at midstream, Agra. Largest concentration of Cu was 617 μg kg^?1, Ni 1,621 μg kg^?1 at midstream while Pb was 1,214 μg kg^?1 at Allahabad in surface sediment. The bioconcentration of Cu, Pb, Ni, and Cr was observed where the largest accumulation of Pb was 2.29 μg kg^?1 in Oreochromis niloticus and 1.55 μg kg^?1 in Cyprinus carpio invaded at Allahabad while largest concentration of Ni was 174 μg kg^?1 in O. niloticus and 124 μg kg^?1 in C. carpio in the midstream of the river. The calculated values of hazard index (HI) for Pb was found more than one which indicated human health concern. Carcinogenic risk value for Ni was again high i.e., 17.02?×?10^?4 which was larger than all other metals studied. The results of this study indicated bioconcentration in fish due to their exposures to heavy metals from different routes which had human health risk implications. Thus, regular environmental monitoring of heavy metal contamination in fish is advocated for assessing food safety since health risk may be associated with the consumption of fish contaminated through exposure to a degraded environment.     

Recovery of benthic invertebrate communities from acidification in Killarney Park lakes

Using a reference-condition comparison, recovery of benthic invertebrate communities from acidification was assessed in three lakes in Killarney Wilderness Park approximately 40–60 km from the massive metal smelters in Sudbury, Canada. Test site analyses (TSAs) were used to compare the park lakes to 20 reference lakes near Dorset Ontario, 200 km to the east. An extension of a previous survey (1997–2001) of two sensitive mayfly species (Stenonema femoratum and Stenacron interpunctatum) was conducted in one of the lakes. TSA results indicate that the three Killarney lakes remain significantly different from reference condition due primarily to higher abundances of a few acid-tolerant families and the presence of some less abundant sensitive families. Colonization rates differ greatly between the two mayfly species presumably because of competition for available habitat. Overall, this study suggests that early colonizers will gain an advantage to out-compete subsequent arrivals, and these competitive interactions will delay the return of communities to reference condition.     

Investigating toxic metal levels in popular edible fishes from the South Durban basin: implications for public health and food security

Contamination of the ocean by heavy metals may have ecosystem-wide implications because they are toxic even if present in trace levels, and the relative ease of their bioaccumulation by marine organisms may affect human health, primarily through consumption of contaminated fish. We evaluated metal concentrations in six different popular edible fish species and estimated the potential health risks from consumption of contaminated fish. There was no correlation between fish length and average metal accumulation although the fish species tended to accumulate significantly more Al and Zn (P?<?0.05) than any of the other metals. Significantly higher Mn concentrations were found in fish gills compared to other body parts in all fish species. Bronze seabream, Catface rockcod, and Slinger seabream had significantly higher mean Cr concentration in the liver than in either the tissues or gills. The highest concentration of Zn in fleshy tissue was in Horse mackerel (56.71 μg g^?1) followed by Bronze seabream (31.07 μg g^?1). Al levels ranged from 5.6 μg g^?1 in Atlantic mackerel to 35.04 μg g^?1 in Horse mackerel tissue while Cu and Cr concentrations were highest in the tissues of Horse mackerel (6.83 and 1.81 μg g^?1, respectively) followed by Santer seabream (3.15; 1.09 μg g^?1) and Bronze seabream (3.09; 1.30 μg g^?1), respectively. The highest tissue concentration of Mn was detected in Bronze seabream (8.23 μg g^?1) followed by Catface rockcod (6.05 μg g^?1) and Slinger seabream (5.21 μg g^?1) while Pb concentrations ranged from a high of 8.44 μg g^?1 in Horse mackerel to 1.09 μg g^?1 in Catface rockcod. However, the estimated potential health risks from fish consumption as determined by the target hazard quotient (THQ) and hazard index (HI) were significantly lower than 1, implying that metals were not present in sufficiently high quantities to be of any health and/or food and security concern in the studied fishes.     

Agro-potentiality of distillery effluent on soil and agronomical characteristics of Abelmoschus esculentus L. (okra)

The present study showed that irrigation of soil with different effluent concentrations (10, 25, 50, 75, and 100 %) of distillery effluent (DE) for 60 days resulted in significant (P?<?0.001) changes in moisture content; electrical conductivity (EC), pH, chlorides (Cl^?), total organic carbon (TOC), exchangeable sodium (Na⁺), available potassium (K⁺), calcium (Ca²⁺), magnesium (Mg²⁺), iron (Fe²⁺), total Kjeldahl nitrogen (TKN), available phosphorus (P), and sulfate (SO₄ ^2?) of soil. The non-significant (P?>?0.05) changes were observed for water-holding capacity and bulk density of the soil. Among various concentrations of DE irrigation, irrigation with 100 % effluent concentration increased moisture content, (24.85 %), EC (77.88 %), Cl^? (285.95 %), TOC (3,171.42 %), exchangeable Na⁺ (241.04 %), available K⁺ (52.49 %), Ca²⁺ (990.37 %), Mg²⁺ (1,751.72 %), TKN (1,417.00 %), available P (305.00 %), and SO₄ ^2? (75.32 %) in the soil and decreased pH (?20.22 %). The more stimulation in agronomical parameters such as shoot length, root length, number of leaves, flowers, pods, dry weight, fresh weight, chlorophyll content, leaf area index, and crop yield of A. esculentus were observed to be inversely proportional to the concentration of effluent water, with the best results being obtained at a dilution of 25 % of DE concentration.