Monitoring of university wastewater within the sewage system and its performance evaluation through integrated constructed wetlands.

Rapid increase in population and industrialization has not only improved the lifestyle but adversely affected the quality and availability of water leading to ample amount of wastewater generation. The major contribution towards wastewater production is from sewage. Regular monitoring and treatment of sewage water is necessary to conserve and enhance the quality of water. The present study focuses on monitoring of sewage water within the sewage system of a residential university. A total of 16 samples from different manholes were collected for physicochemical and heavy metals analysis and compared with final effluent collected from integrated constructed wetlands (ICWs) to assess its removal efficiency. The mean concentrations of influent and effluent were compared with national environmental quality standards (NEQS) for municipal discharge (pH 6-9, COD 150 mg/L, TSS 200 mg/L and TDS 3500 mg/L) and international agricultural reuse standards (IARS) (pH 6-8, COD <150 mg/L, TSS < 100 mg/L) respectively. Among all physicochemical parameters, influent values for chemical oxygen demand (COD) (169.56-258.36) mg/L exceeded the limit of NEQS for discharge into inland waters, whereas for total suspended solids (TSS) the concentration exceeded for discharge into STP (406 mg/L) and inland waters (202.33 mg/L). However, effluent concentrations for all the parameters were found within the permissible limit set by IARS. The removal efficiency for different parameters such as phosphate- phosphorus (PO43-P), COD, TSS, total dissolved solids (TDS) and total kjeldahl nitrogen (TKN) were 52, 53, 54, 35, and 36%, respectively. Heavy metal concentrations were compared with WHO guidelines among which lead (Pb) in effluent and chromium (Cr) in influent exceeded the limit (Pb 0.01 and Cr 0.05 mg/L). Interpolation results showed that zone 2 was highly contaminated in comparison to zone 1 & 3. Statistical analysis showed that correlation of physicochemical parameters and heavy metals was found significant (p < 0.05).

Multi-biomarkers approach to determine the toxicological impacts of sulfamethoxazole antibiotic on freshwater fish Cyprinus carpio.

Antibiotics are increasingly detected in the aquatic environment and are raising severe concerns for human and ecological health. Sulfamethoxazole being a widely recommended antibiotic in both human and veterinary medicine is consequently found in the aquatic environment. The current research was aimed to investigate the potential bioaccumulation and sub-lethal toxicity in terms of oxidative stress and histopathology of targeted antibiotic sulfamethoxazole in Cyprinus carpio at environmentally relevant concentrations over a prolonged period. Fish were exposed for 28 days to environmentally realistic concentrations (25-200 µg/L) of sulfamethoxazole. HPLC analysis revealed an inverse relationship between dosages applied and bioaccumulation in fish muscle tissues. The highest concentrations of sulfamethoxazole in the muscle tissues exposed to 25, 50, 100 and 200 µg/L were 124, 202,104.5, and 123.2 ng/g, respectively at different sampling times. Moreover, exposure to sulfamethoxazole enabled ROS (Reactive oxygen species) production in both brain and gill tissues of fish, where the increase in ROS formation was dose and time dependent. Furthermore, histopathological analysis of gills and liver revealed various alterations including pycnotic nuclei, bile stagnation, vacuolization in the liver, and partial and complete fusion of lamella and blood congestion in gills, respectively. Organ pathological index also revealed that the intensity of tissue damage increased as sulfamethoxazole dosage was increased. Quantitative evaluation of gills morphometric parameters divulged that severity of histopathological changes increased with time for all the exposed groups at the end of exposure time (28th day) indicating physio-metabolic turmoil caused by molecular and biochemical action of sulfamethoxazole. In conclusion, the assessment of bioaccumulative potential, measurement of ROS, and histopathology of Cyprinus carpio appeared to be a useful biomarker to evaluate the toxic impacts of antibiotics on the health of fish.

Clearing the Clutter: Antiatherosclerotic activity of Eucalyptus camaldulensis crude extract.

Plant components have been extensively evaluated for their pharmacological activities. This study provides scientific rationale towards the therapeutic effect of Eucalyptus camaldulensis aqueous bark extract against induced atherosclerosis and hyperlipidemia in pigeons. Phytochemical components of Eucalyptus bark extract possess a great antioxidant activity that potentially reduced the risk of heart diseases. A total of 42 Pigeons of both sexes were distributed into negative control (fed normal grain diet), hyperlipidemic control (fed HFD 1% animal fat oil and 0.1% cholesterol for 3 months), test groups of variable doses (0.05, 0.1, 0.2 to 0.4 gms/kg BW for 21 days) and the group received atorvastatin daily after induction used. At the end of the experiment biochemical and histological evaluation has been performed. After HFD induction the serum levels of liver enzyme AST, glucose, urea, cholesterol, LDL, VLDL, and TG were significantly increased with the reduction in HDL levels. The atherogenic index was also found significantly raised. Microscopic examination of the liver and aorta showed the appearance of lipid-filled foam cells all over the liver parenchyma and intima after the HFD induction. Thus it was concluded that Eucalyptus aqueous bark extract can be effective against atherosclerosis and hyperlipidemia.

Combined pretreatment of sugarcane bagasse using alkali and ionic liquid to increase hemicellulose content and xylanase production.

BACKGROUND: Lignin in sugarcane bagasse (SB) hinders its utilization by microorganism, therefore, pretreatment methods are employed to make fermentable components accessible to the microbes. Multivariate analysis of different chemical pretreatment methods can aid to select the most appropriate strategy to valorize a particular biomass. RESULTS: Amongst methods tested, the pretreatment by using sodium hydroxide in combination with methyltrioctylammonium chloride, an ionic liquid, (NaOH+IL) was the most significant for xylanase production by Bacillus aestuarii UE25. Investigation of optimal levels of five significant variables by adopting Box-Behnken design (BBD) predicted 20 IU mL- 1 of xylanase and experimentally, a titer of 17.77 IU mL- 1 was obtained which indicated the validity of the model. The production kinetics showed that volumetric productivity of xylanase was much higher after 24 h (833.33 IU L- 1 h- 1) than after 48 h (567.08 IU L- 1 h- 1). The extracted xylan from SB induced more xylanase in the fermentation medium than pretreated SB or commercially purified xylan. Nuclear Magnetic Resonance, Fourier transform infrared spectroscopy and scanning electron microscopy of SB indicated removal of lignin and changes in the structure of SB after NaOH+IL pretreatment and fermentation. CONCLUSION: Combined pretreatment of SB with alkali and methyltrioctylammonium chloride appeared better than other chemical methods for bacterial xylanase production and for the extraction of xylan form SB.

Evaluation of genotoxicity and hematological effects in common carp (Cyprinus carpio) induced by disinfection by-products.

Disinfection is intended to improve drinking water quality and human health. Although disinfectants may transform organic matter and form disinfection by-products (DBPs), many are branded as cyto- and genotoxic. Traditionally, research focuses on the effects of DBPs on human health, but cytogenic impacts on aquatic organisms still remain ill defined. The current study examines the potential toxic effect of chloroform and iodoform (DBPs) on Cyprinus carpio, selected as a model organism. Fish specimens were exposed to various concentrations of DBPs primarily based on LD50 values, where acute toxicity was monitored for 96 h. Headspace SPME extraction through gas chromatography was employed to assess the effects of spiked DBPs doses in fish blood. Cytotoxicity was monitored using Comet assay. Tail length, tail DNA, and olive tail moment values were quantified to be significant (P < 0.05) as compared to control. A statistically significant (P < 0.05) decrease in all blood parameters (hematology) was observed. Changes in biochemical indices (glucose, total protein, and alanine aminotransferase (ALT)) were also significant. ALT secretion was significantly increased (93 ± 0.05 and 82.8 ± 0.1 U/L) at higher concentration compared to control (56 ± 0.1 U/L), suggesting liver damage. Results demonstrated that iodoform was statistically more damaging as compared to chloroform.

Plant uptake and leaching potential upon application of amendments in soils spiked with heavy metals (Cd and Pb).

The aim of this study was to assess the effects of soil amendments (organic and inorganic) on phytoavailability and leaching of cadmium (Cd) and lead (Pb) during enhanced phytoextraction. The vertical column study was carried out to investigate the metal leaching meanwhile studying plant biomass and metals uptake for phytoextraction by Pelargonium hortroum. For this purpose, soil amendments at several concentration levels, such as ethylene diaminetetraacetic acid (EDTA 0, 4, 5 mmol kg-1), ammonium nitrate (0, 8, 10 mmol kg-1), citric acid (0, 8, 10 mmol kg-1), compost (0, 8%, 10%) and titanium dioxide nanoparticles (TNPs, 0, 80, 100 mg kg-1) were used. Results revealed that EDTA efficiently improved Cd and Pb accumulation (mg kg-1) in shoots and roots. Cd accumulation was significantly increased by 270%, 44%, 145%, and 6.4% in shoot and 94%, 19%, 48% and 14% in root upon EDTA, ammonium nitrate, citric acid and TNPs application, respectively compared to the control without amendment (WA). Similarly, Pb accumulation was significantly increased by 71%, 58% and 52% in shoot and 88.8%, 70.6% and 64.6% in root upon exposure to higher levels of EDTA, citric acid and ammonium nitrate, respectively when compared to the WA control. Application of TNPs reduced the Pb-accumulation in shoots and roots by 33% and 28%, respectively. Similarly, the Pb-accumulation in shoots and roots was decreased by 39% and 35%, respectively upon compost addition. Plant biomass was significantly increased upon application of soil amendments, with the exception of EDTA. The maximum Cd and Pb uptake was found in citric acid amended soil. Leachate analysis revealed that the concentrations of Cd and Pb were increased by 109% and 101% in leachates upon EDTA application as compared to other amendments. In comparison with other amendments, citric acid may be recommended as an environmentally friendly alternative for non-biodegradable EDTA for enhanced phytoextraction of Cd and Pb.

Impact of meteorological conditions on the water quality of wastewater treatment systems: a comparative study of phytoremediation and membrane bioreactor system.

Two demonstration wastewater treatment systems, i.e. a phytoremediation system and a membrane bioreactor (MBR) system, were studied for a six-month period from August 2016 to January 2017. The phytoremediation system consists of wetland cells implanted with diverse phytoremediation macrophyte species at NUST H-12 sector Islamabad, Pakistan, while the MBR system comprises primary clarifiers, membrane tanks and bio tanks that treat domestic wastewater through hybridization of biological and biomechanical techniques. The phytoremediation system receives domestic wastewater at the rate of 283 m3/d, and greater hydraulic efficiencies were achieved because of compartmentalization and higher aspect ratios, whereas the MBR system receives 50 m3/d. The present study was conducted to analyze and compare the correlation between water quality parameters of wastewater treatment systems and meteorological conditions. Statistically significant correlation was exhibited between eight water quality parameters (pH, EC, turbidity, dissolved oxygen, total suspended solids (TSS), chemical oxygen demand (COD), biological oxygen demand (BOD) and total coliforms (TC)) and meteorological factors (ambient temperature and relative humidity). Predominant species isolated and identified through polymerase chain reaction and 16S rRNA sequencing from wastewater of the phytoremediation system and sludge of the MBR system belong to the phylum Proteobacteria with relatively higher abundance of Enterobacter, Shigella, Escherichia and Salmonella genera.

Effect of trihalomethanes (chloroform and bromoform) on human haematological count.

With the increasing concerns about the harmful effects of disinfection products, the process of chlorination is becoming questionable. Bromoform and chloroform are among the most frequently occurring disinfection by-products. Haematological parameters are an important indicator of human well-being which is why the prime objective of the current study was to conduct a dose-response assessment to investigate the effects of trihalomethanes on human haematological count. Blood samples of healthy subjects were exposed to different concentrations (10, 30 and 50 µg/mL) of chloroform and bromoform in vitro to analyse how these compounds affected the haematological count with increasing dose concentrations. Headspace gas chromatography analysis was also conducted on samples to assess the difference between measured and spiked values of doses. The results indicated that the damage caused by bromoform was statistically more significant as compared to chloroform. Haemoglobin (HGB) and mean corpuscular haemoglobin concentration levels lowered as they were significantly affected (p < 0.05) by bromoform at all administered doses. It also significantly damaged platelet level at doses of 30 (p < 0.05) and 50 µg/mL (p < 0.01). Conversely, the damage caused by chloroform was statistically less significant (p > 0.05).

Performance Evaluation of Membrane-Based Septic Tank and Its Reuse Potential for Irrigating Crops.

Membrane technology, being the most emerging wastewater treatment option, has gained substantial importance with the massive objective of the reuse potential of wastewater. Keeping this in view, the present study was conducted with the rationale to evaluate the performance efficiency of membrane-based septic tank (MBST), and its reuse perspective for irrigating crops. The septic tank was designed by submerging a woven fiber microfiltration membrane module to treat domestic wastewater. Three crops Triticum aestivum (wheat), Coriandrum sativum (coriander), and Mentha arvensis (mint) were selected to be irrigated with treated MBST effluent, untreated wastewater, and tap water (as a control) for comparative growth analysis. Two pathogenic strains, Escherichia coli and Salmonella sp. were selected as reference microbes and their translocation rate was observed in root, shoot, and leaves. Upon maturity, the roots, shoots, and leaves of the above-mentioned plants were aseptically removed for microbiological analysis. Strains were analyzed, using analytical profile index and PCR analysis. Maximum removal efficiencies for MBST in terms of chemical oxygen demand (COD), turbidity, nutrients deduction (phosphorus), and indicator bacteria (Escherichia coli) were found to be 73, 96, 48, and 88%, respectively. Significant bacterial load reduction (p < 0.001) in terms of E. coli (3.8 log CFU/100 mL) and helminths (2 eggs/L) was observed in treated water. High plant yield was observed when irrigated with treated water as compared to tap water, as minimal nutrient removal (48%) was recorded in treated water, with the germination percentage of 88.8%.

Synthesis and bio-molecular study of (+)-N-Acetyl-α-amino acid dehydroabietylamine derivative for the selective therapy of hepatocellular carcinoma.

BACKGROUND: The purpose of present work is to synthesize novel (+)-Dehydroabietylamine derivatives (DAAD) using N-acetyl-α-amino acid conjugates and determine its cytotoxic effects on hepatocellular carcinoma cells. METHODS: An analytical study was conducted to explore cytotoxic activity of DAAD on hepatocellular carcinoma cell lines. The cytotoxicity effect was recorded using sulforhodamine B technique. Cell cycle analysis was performed using Propidium Iodide (PI) staining. Based on cell morphology, anti growth activity and microarray findings of DAAD2 treatment, Comet assay, Annexin V/PI staining, Immunoperoxidase assay and western blots were performed accoringly. RESULTS: Hep3B cells were found to be the most sensitive with IC50 of 2.00 ± 0.4 µM against (+)-N-(N-Acetyl-L-Cysteine)-dehydroabietylamine as DAAD2. In compliance to time dependent morphological changes of low cellular confluence, detachment and rounding of DAAD2 treated cells; noticeable changes in G2/M phase were recorded may be leading to cell cycle cessation. Up-regulation (5folds) of TUBA1A gene in Hep3B cells was determined in microarray experiments. Apoptotic mode of cell death was evaluated using standardized staining procedures including comet assay and annexin V/PI staining, Immuno-peroxidase assay. Using western blotting technique, caspase dependant apoptotic mode of cell death was recorded against Hep3B cell line. CONCLUSION: It is concluded that a novel DAAD2 with IC50 values less than 8 µM can induce massive cell attenuation following caspase dependent apoptotic cell death in Hep3B cells. Moreover, the corelation study indicated that DAAD2 may have vital influence on cell prolifration properties.

Bacterial assisted degradation of chlorpyrifos: The key role of environmental conditions, trace metals and organic solvents.

Wastewater from pesticide industries, agricultural or surface runoff containing pesticides and their residues has adverse environmental impacts. Present study demonstrates effect of petrochemicals and trace metals on chlorpyrifos (CP) biotransformation often released in wastewater of agrochemical industry. Biodegradation was investigated using bacterial strain Pseudomonas kilonensis SRK1 isolated from wastewater spiked with CP. Optimal environmental conditions for CP removal were CFU (306 × 10(6)), pH (8); initial CP concentration (150 mg/L) and glucose as additional carbon source. Among various organic solvents (petrochemicals) used in this study toluene has stimulatory effect on CP degradation process using SRK1, contrary to this benzene and phenol negatively inhibited degradation process. Application of metal ions (Cu (II), Fe (II) Zn (II) at low concentration (1 mg/L) took part in biochemical reaction and positively stimulated CP degradation process. Metal ions at high concentrations have inhibitory effect on degradation process. A first order growth model was shown to fit the data. It could be concluded that both type and concentration of metal ions and petrochemicals can affect CP degradation process.

Efficacy of UV-C photolysis of bisphenol A on transcriptome alterations of genes in zebrafish embryos.

The purpose of this study was to investigate the efficacy of UV-C direct photolysis of bisphenol A (BPA) as a remediation method of BPA contamination. We used zebrafish embryos as a model organism to test the toxicity and residual biological activity by measuring cytochrome P4501A1 (CYP1A), aromatase B (Aro B) and heat shock proteins (HSP-70) transcript levels. The mRNA levels of CYP1A gene increased about two fold while exposure of zebrafish embryos at 72 hpf resulted in significant induction (P = 0.048) of Aro B at 100 µg/L of BPA. Exposure of zebrafish embryos at 72 hpf to increasing concentrations of BPA resulted in significant induction (P = 0.0031) of HSP-70 transcript level. UV treatment of BPA resulted in a significant reduction in toxicity by reducing mortality of zebrafish embryos. The results suggest that UV-C direct photolysis may be an effective method for remediation of BPA contamination. Further studies will be necessary for better understanding of the identity and relative activity of the UV degradation by-products.

Monitoring of chlorination disinfection by-products and their associated health risks in drinking water of Pakistan.

This study reports the baseline data of chlorination disinfection by-products such as trihalomethanes (THMs) and their associated health risks in the water distribution network of Islamabad and Rawalpindi, Pakistan. THM monitoring was carried out at 30 different sampling sites across the twin cities for 6 months. The average concentration of total trihalomethanes (TTHMs) and chloroform ranged between 575 and 595 µg/L which exceeded the permissible US (80 µg/L) and EU (100 µg/L) limits. Chloroform was one of the major contributors to the TTHMs concentration (>85%). The occurrence of THMs was found in the following order: chloroform, bromodichloromethane > dibromochloromethane > bromoform. Lifetime cancer risk assessment of THMs for both males and females was carried out using prediction models via different exposure routes (ingestion, inhalation, and dermal). Total lifetime cancer risk assessment for different exposure routes (ingestion, inhalation, and skin) was carried out. The highest cancer risk expected from THMs seems to be from the inhalation route followed by ingestion and dermal contacts. The average lifetime cancer risk for males and females was found to be 0.51 × 10⁻³ and 1.22 × 10⁻³, respectively. The expected number of cancer risks per year could reach two to three cases for each city.

Evaluation of anthropogenic effects on water quality and bacterial diversity in Rawal Lake, Islamabad.

Water quality and bacterial diversity in the surface water of Rawal Lake was investigated for a period of 8 months to evaluate the pollution load from anthropogenic effects of surrounding areas. Rawal Lake in Islamabad, Pakistan is an artificial reservoir that provides the water needs for the residents of Rawalpindi and Islamabad. Grabbed water samples were collected according to standard protocols from ten different locations of the lake and tributaries keeping in view the recharge points from adjacent areas. Temperature, pH, electrical conductivity, dissolved oxygen, total dissolved solids, hardness, alkalinity, and turbidity of water samples were determined to study the water quality characteristics. The physicochemical parameters showed higher values at the tributaries as compared to the sampling locations within the lake such as values of hardness and alkalinity were 298 and 244 mg/L, respectively, at the tributary of the Nurpur stream. Bacterial strains were isolated by streaking on differential and selective growth media by observing colony morphology and other biochemical tests such as Gram reaction, oxidase, and catalase test. Template DNA was prepared from pure cultivated bacteria and 16S rRNA gene analysis was performed using universal primers for bacteria. Sequencing was performed by using BigDye terminator cycle sequencing kit. Sequences of nearest relative microbial species were identified by using basic local alignment search tool and used as reference sequences for phylogenetic analysis. Phylogenetic trees were inferred using the neighbor-joining method. Sequencing and phylogenetic characterization of microbes showed various phylotypes, of which Firmicutes, Teobacteria, and Proteobacteria were predominant.

Comparative evaluation of in vitro cytotoxic effects among parent abietyl alcohol and novel fatty acid ester derivatives against MCF7 and hepatocellular carcinoma cell lines.

Synthesis of twelve hitherto unreported esters of abietyl alcohol and screening of these esters against four cancer cell lines including one breast cancer line MCF7 and four hepatocellular carcinoma cell lines (HCC) Huh7, Hep3B, Snu449 and Plc has been determined using SRB assay. The Cell cycle progression showed changes in cellular behaviour after 48 and 72 hours in MCF7 and Huh7 cell lines. Abietyl alcohol was obtained from the reduction of abietic acid, a tricyclic diterpene, isolated from oleoresin of Pinus longifolia Roxberghii.

Synthesis and characterization of amino acid conjugates of oleanolic acid and their in vitro cytotoxic effect on HCC cell lines.

Oleanolic acid (3ß-hydroxy-olean-12-en-28-oic acid; OA-01), a pentacyclic triterpene, exhibit a wide range of pharmacological and biological activities. We have isolated oleanolic acid from methanolic extract of Periploca aphylla, collected from surroundings of Karachi in the month of February. Furthermore, four known and two new C-28 amino acid conjugates of oleanolic acid were prepared to explore potential of these compounds on HCCs and one breast cancer cell line. Cytotoxic effects revealed that as compare to parent compound (OA-01), two derivatives OA-04 (p<0.0001) and OA-06 (p<0.01) showed significantly increased/higher inhibition rates.

Cancer and non-cancer risk assessment of trihalomethanes in urban drinking water supplies of Pakistan.

This study aims at monitoring and risk assessment of trihalomethanes (THMs) such as chloroform, bromodichloromethane, dibromochloromethane and bromoform, in the drinking water supplies of Rawalpindi and Islamabad. THMs were monitored at twenty locations in these twin cities using solid phase micro extraction-gas chromatography (SPME-GC). Total concentration of THMs was ranged between 21 and 373µg/L, whereas both cities had an average total THMs concentration of 142 and 260µg/L, respectively. Chloroform was found as one the major contributor to the THMs concentration (>85%). The occurrence of THMs followed the given order: chloroform, bromodichloromethane>dibromochloromethane>bromoform. Lifetime cancer risk assessment of THMs was carried out using prediction models via different exposure routes (ingestion, inhalation and dermal). An average lifetime cancer risk was found to be 0.74×10(-4) and 1.24×10(-4) for Rawalpindi and Islamabad, respectively. The number of expected cancer cases per year could reach two cases for each city. Hazard index values were found below unity for both the cities implying that there would be no considerable non-cancer risk. Oral ingestion was found to be one of the main routes of exposure for both types of risk which was followed by inhalation and dermal routes.

Sulfamethoxazole (SMX) Alters Immune and Apoptotic Endpoints in Developing Zebrafish (Danio rerio).

Sulfamethoxazole (SMX) is a broad-range bacteriostatic antibiotic widely used in animal and fish farming and is also employed in human medicine. These antibiotics can ultimately end up in the aquatic ecosystem and affect non-target organisms such as fish. To discern the effect of SMX on developing zebrafish embryos and larvae, we investigated a broad range of sub-lethal toxicity endpoints. Higher concentrations of SMX affected survivability, caused hatch delay, and induced malformations including edema of the yolk sac, pericardial effusion, bent tail, and curved spine in developing embryos. Lower levels of SMX provoked an inflammatory response in larvae at seven days post fertilization (dpf), as noted by up-regulation of interferon (ifn-γ) and interleukin 1ß (il-1ß). SMX also increased the expression of genes related to apoptosis, including BCL2-Associated Agonist of Cell Death (bad) and BCL2 Associated X, Apoptosis Regulator (bax) at 50 µg/L and decreased caspase 3 (casp3) expression in a dose-dependent manner. SMX induced hyperactivity in larval fish at 500 and 2500 µg/L based upon the light/dark preference test. Collectively, this study revealed that exposure to SMX can disrupt the immune system by altering host defense mechanisms as well as transcripts related to apoptosis. These data improve understanding of antibiotic chemical toxicity in aquatic organisms and serves as a baseline for in-depth environmental risk assessment of SMX and antibiotics.

Detection in influx sources and estimation of microplastics abundance in surface waters of Rawal Lake, Pakistan.

The ever-growing production, usage and poor waste management practices of plastics are causing microplastics intrusion in freshwater environments all over the world. The identification of inflow processes and sources is equally important as the assessment of microplastic concentrations in freshwater. This study reports microplastic presence in the influx sources and provides an overall estimation of microplastic concentration in the surface water of a freshwater reservoir, Rawal Lake, Islamabad. In the current study, six major tributaries of Rawal lake were assessed for microplastic presence, out of which four tributaries showed microplastic contamination. Microplastics concentration in the lake ranged from 6.4 ± 0.5 particles/m³ to 8.8 ± 0.5 particles/m³. All the identified microplastics in tributaries and lake were secondary except granules. The prominent shape of microplastics among the studied waters was film, with transparent being the most frequent plastic-type according to color. Polyethylene (LDPE and HDPE) were the dominant type of microplastics found in the lake and the tributaries. More than 72% of microplastics had a size of 0.3-0.1 mm. This study provides a better understanding of the extent of microplastic pollution assessment in a freshwater lake with equal emphasis on microplastic presence in influx sources and the relationship of microplastics with fundamental water quality indicators (pH, temperature, dissolved oxygen, and biological oxygen demand), which may be beneficial in impeding the introduction of microplastics at sources.

Toxic effects of pristine and aged polystyrene microplastics on selective and continuous larval culture of acorn barnacle Amphibalanus amphitrite.

This study evaluates the toxicity of pristine (Unwashed) and aged, clean (Biofilm-) or fouled (Biofilm+), PS microspheres (3 µm,10 µm), using Washed particles as a reference material, on selective and continuous larval culture of Amphibalanus amphitrite. Exposure to 3 µm Unwashed and Biofilm+ particles for 24 h induced significant mortality (60 % and 57 % respectively) in stage II larvae. Stage II and VI nauplii showed greater uptake of 3 µm Biofilm- particles. Accumulative exposure to microplastics in continuous larval culture significantly affected the naupliar survival, particularly of stage III and IV. Cumulative mortality was > 70% after exposure to 3 µm Unwashed and 10 µm Biofilm+ particles. Unwashed particles with increasing concentration and aged particles with increasing size, delayed the development of nauplii to cyprids. Though,> 50% cyprids showed successful settlement however the highest concentration of 3 µm Biofilm+ microspheres inhibited the settlement and induced precocious metamorphosis in 9 % of the cyprids.