Spatio-temporal distribution of microplastics in water and sediment samples of the Plankenburg river, Western Cape, South Africa.

Microplastic (MPs) pollution has become a subject of environmental concern due to its wide ubiquity in the environment. Microplastics are possible sources of other hazardous chemicals to aquatic organisms due to their composition and sorption properties. In this study, MPs occurrence in water and sediment samples of the Plankenburg River, Western Cape, South Africa was investigated. The physicochemical characterization of the river water was done onsite. 30 L water samples were collected and filtered in 10 L triplicates through a 250 µm mesh onsite using a metal bucket. An additional 12 L sample was collected and filtered in 4 L triplicates through 20 µm mesh in the laboratory. The extraction of MPs from water in the laboratory was by density separation. Sediment samples were also collected at the selected sites, oven-dried and microplastics in the laboratory. Sampling was conducted over four seasons - spring, summer, autumn, and winter. Microplastics were classified by visual observation and Fourier Transform Infrared Spectroscopy (FTIR-ATR). The seasonal distribution of MPs in the surface water samples varied across all sites. However, spring samples had the highest MPs occurrence (5.13 ± 6.62 MP/L) and the least, in autumn (1.52 ± 2.54 MP/L). The MPs in sediment samples were observed in spring (1587.50 ± 599.32 MP/kg). Fibres were the most dominant microplastic particle type (shape), with a size range of 500-1000 µm at the different sites. The infrared spectroscopic analysis confirmed the dominant polymer type to be polyethylene. This study provides an understanding of the microplastic occurrence in the Plankenburg River system and gives a baseline for future monitoring and assessment of water and sediment in the South African freshwater systems.

The potential ecological risk of veterinary pharmaceuticals from swine wastewater on freshwater aquatic environment.

The impact of pharmaceutical residue transport in the aquatic ecosystem has become an increasing subject of environmental interest due to the inherent bioactivity of trace levels of antibiotics and the negative environmental and public health impact. In this study, three veterinary pharmaceuticals including tetracycline, ivermectin, and salicylic acid were investigated in a piggery effluent from Western Cape, South Africa. Three freshwater organisms' taxonomic groups (Pseudokirchneriella subcapitata, Daphnia magna, and Tetrahymena thermophila) were used to determine the ecological risk of different treated piggery effluent concentration range of 1%, 10%, and 20% and a cocktail mixture of veterinary pharmaceuticals of environmental concerns. The average concentration of veterinary pharmaceuticals was in the range of 47.35, 7.19, and 1.46 µg L-1 for salicylic acid, chloro-tetracycline, and ivermectin, respectively. P. subcapitata exposed to 20% piggery wastewater effluent at 24- and 48-h EC50 showed a toxicity value of 14.2% and 13.6% (v/v), respectively. The study established the ecological risk of the test compounds as low to medium risk for low-level dose and low concentrations of piggery effluent. The relative sensitivity ranking of the taxa drawn is microalgae > protozoa > Cladocera. The study results demonstrated that a high dose of piggery effluent and mixtures of veterinary pharmaceutical can pose a high risk in freshwater ecosystems. PRACTITIONER POINTS: Transport processes of veterinary antibiotics into the environment were investigated. Dilution effect of the veterinary pharmaceutical on the antibiotic levels exists. High dose of piggery effluent presented an ecological risk.

The Importance of Fostering and Funding Scientific Research, and its Relevance to Environmental Toxicology and Chemistry.

What do environmental contaminants and climate change have in common with the virus SARS-CoV-2 and the disease COVID-19? We argue that one common element is the wealth of basic and applied scientific research that provides the knowledge and tools essential in developing effective programs for addressing threats to humans and social-ecological systems. Research on various chemicals, including dichlorodiphenyltrichloroethane and per- and polyfluoroalkyl substances, resulted in regulatory action to protect environmental and human health. Moreover, decades of research on coronaviruses, mRNA, and recently SARS-CoV-2 enabled the rapid development of vaccines to fight the COVID-19 pandemic. In the present study, we explore the common elements of basic and applied scientific research breakthroughs that link chemicals, climate change, and SARS-CoV-2/COVID-19 and describe how scientific information was applied for protecting human health and, more broadly, socio-ecological systems. We also offer a cautionary note on the misuse and mistrust of science that is not new in human history, but unfortunately is surging in modern times. Our goal was to illustrate the critical role of scientific research to society, and we argue that research must be intentionally fostered, better funded, and applied appropriately. To that end, we offer evidence that supports the importance of investing in scientific research and, where needed, ways to counter the spread of misinformation and disinformation that undermines legitimate discourse. Environ Toxicol Chem 2023;42:581-593. © 2022 SETAC.

Phenolic compounds occurrence and human health risk assessment in potable and treated waters in Western Cape, South Africa.

Phenolic pollutants from industrial and agricultural activities pose a major threat to the world's potable water supply. The persistent micro-pollutants often find their way into drinking water sources with possible adverse human health implications. In this study, bottled water, tap water, and wastewater treatment plant (WWTP) effluent samples from the Boland region of the Western Cape, South Africa were assessed to determine 4-chlorophenol (4-CP) and 2,4-dichlorophenol (2,4-DCP) levels using HPLC/DAD instrumentation. The selected area is known for its vast agricultural ventures and wineries. Evaluation of the human health risk (cancer risk) for the pollutants was conducted using the hazard quotient (HQ). The Ames mutagenicity test was also conducted using the Salmonella typhimurium T98 and T100 strains and the S9 activation enzyme. Trace levels of the phenolics were detected in the samples with a range of 9.32 × 10-7-1.15 × 10-4 mg/L obtained for 4-CP, and 8.80 × 10-7-1.72 × 10-4 mg/L recorded for 2,4-DCP. Both compounds had levels below the limit of 0.01 mg/L prescribed by South African legislation. The assessed HQ for the phenolic concentrations indicates a low level of potential ecological risk and none of the samples had a cancer risk value that exceeded the regulatory limit. The possibility of the analyzed samples causing cancer is unlikely, but non-carcinogenic adverse effects were found. Strong mutagenicity was observed for the T98 strains with a potential ability to cause mutation toward the insertion or deletion of a nucleotide. The T100 bacterial strain showed very slight mutagenicity potential, however, it is unlikely to cause any mutation. The levels of phenolics in the potable water samples may pose a significant threat to human health. Hence, screening persistent organic chemicals in potable water sources and evaluating their potential human health effects is pertinent to prevent associated health challenges.

Effects of municipal wastewater treatment plant effluent quality on aquatic ecosystem organisms.

The management and quality monitoring of wastewater have an important role in sustainable development. A recent approach in environmental protection involves the ecotoxicological assessment of effluents to complement the usual chemical evaluations. This study assessed the impacts of wastewater treatment plant (WWTP) effluent quality in a location in Western Cape province, South Africa using organisms that bear different ecosystem-level function responsibilities like the Pseudokirchneriella subcapitata (microalgae), Daphnia magna (crustaceans), and Tetrahymena thermophila (protozoan) in addition to the physicochemical parameters. The effluent showed values of chemical oxygen demand (COD; 41-83 mg L-1), dissolved oxygen (DO; 2.7-3.1 mg L-1), Redox potential (189-265 mV), and total dissolved solids (TDS; 656-718 ppm). The protozoan Tetrahymena thermophila ecotoxicity test exhibited toxic effects of the effluents within 24-h with a mean lethal value (LC50) of 1.12% for the winter season. The findings of this study revealed that analyzed physicochemical parameters are within the regulatory water quality acceptable standard thresholds with few exceptions, while the biotests were able to determine the toxicity levels and sensitivities of each test. The results showed that the WWTP whole effluent exerted toxicity to test organisms, but dilution can mitigate the effects considerably. The use of ecotoxicological assessment methods for municipal WWTP effluent may enhance existing water management strategies.

Investigation into the bacterial diversity of sediment samples obtained from Berg River, Western Cape, South Africa.

This study used conventional culturing and 16S rRNA metagenomics analyses to assess the diversity of bacterial communities in sediment samples obtained from the Berg River, Western Cape, South Africa. Samples were collected from six points: a residential and recreational area, an industrial area, an informal residential settlement, a point next to a wastewater treatment plant (WWTP), a pumping station, and a residential and agricultural farming area along the river. High bacterial counts recorded on general selective and differential culture media signify substantial microbial contamination along the sampling sites. The most prevalent bacterial phyla detected (through metagenomics analyses) along the sampling sites were Proteobacteria (61%), Planctomycetes (9.5%), Firmicutes (7.8%), Bacteroidetes (5%), Acidobacteria (4.6%), and Actinobacteria (4.6%). Some members of the identified predominant bacterial phyla, genera, and classes are important public health bacteria that have been implicated in human diseases and outbreaks, while some others are metal or hydrocarbon tolerant, indicating possible significant environmental pollution. Notable human pathogenic genera such as Bacillus, Clostridium, Shigella, Legionella, Mycobacterium, and Pseudomonas were identified in varying percentages at five of the six sampling areas. Fecal contamination was particularly rife at all residential areas, with the informal housing area being the most notably polluted. Diverse functional pathways were predicted for identified bacteria, such as those associated with different chronic and infectious human diseases as well as those related to hydrocarbon and metal remediation. The point next to a WWTP contained vastly diverse groups of bacterial contaminants as well as the most abundant pathway identities and titles.

Acute toxicity of piggery effluent and veterinary pharmaceutical cocktail on freshwater organisms.

Intensive livestock farming has increased the use of veterinary pharmaceuticals in many developing countries, and this is considered a significant concern to the freshwater ecosystem. However, the information on the potential acute toxicity of piggery effluent waste and the veterinary pharmaceutical effluent discharged into the aquatic environment is limited. This study assessed the adverse effect of a piggery effluent and the cocktail mixtures of high- and low-level doses of three frequently occurring veterinary pharmaceuticals (tetracycline (TETR), ivermectin (IVER), and salicylic acid (SALA)) on freshwater organisms using three representative freshwater biotests organisms: Pseudokirchneriella subcapitata (P. subcapitata), Daphnia magna (D. magna), and Tetrahymena thermophila (T. thermophila). The freshwater organism test results showed that the 24-h and 48-h EC50 algal toxicity to P. subcapitata exposed to 10% unfiltered piggery effluent were 25.6 and 49.3% respectively while the 24-h LC50 value to Cladocera, D. magna exposed to unfiltered piggery effluent was 23.2 (17.7-30.4)%. The 24-h EC50 protozoan toxicity to T. thermophila exposed to 1% HLD veterinary pharmaceuticals was 0.014 µg/L. Thus, the study established the different sensitivities of freshwater organisms to various percentage levels of piggery effluent and high- and low-level doses of veterinary pharmaceutical. The piggery effluent and the pharmaceutical cocktail mixtures have potential toxicological effects on the freshwater ecosystem.

Occurrence and probabilistic risk assessment of PAHs in water and sediment samples of the Diep River, South Africa.

This study investigated the levels of polycyclic aromatic hydrocarbons (PAHs) in water and sediment samples of the Diep River freshwater system of Western Cape Province, South Africa. A solid-phase extraction - gas chromatography - flame ionisation detection (SPE-GC-FID) method was utilised to simultaneously determine the 16 United States Environmental Protection Agency (US EPA) listed priority PAHs in water and sediment samples. The seasonal averages of individual PAH detected at the studied sites, ranged between not detected (Nd) and 72.38 ± 9.58 µg/L in water samples and between Nd and 16.65 ± 2.63 µg/g in the corresponding sediment samples. The levels of PAHs measured in water and sediment samples were subjected to probabilistic risk assessment to predict the possibility of regulatory values being exceeded. The average percentage exceedence of 63.26 was obtained for PAHs in water samples of the Diep River, while the corresponding average percentage exceedence obtained for sediment sample was 63.71. Sufficient exposure of humans and aquatic organisms to the exceedance levels obtained, would cause adverse health effect.

Microplastics in aquatic environment: characterization, ecotoxicological effect, implications for ecosystems and developments in South Africa.

Microplastics are small-size plastic piece scales (particles < 5 mm) in sediments and waters which interact with environment and organisms by various means. Microplastics are becoming a universal ecological concern since they may be a source of hazardous chemicals to marine organisms and environments. Recent research suggests microplastics could enable the transfer of hydrophobic aquatic pollutants or chemical additives to biota. Even though microplastic presence and interactions are recently being detected in marine and freshwater systems, the fate of microplastics is still very poorly understood. This literature review is a summary of the sources and transport of microplastics, their interactions with toxic chemicals and the methodologies for chemical quantification and characterization of microplastics. The environmental outcome and impact of microplastics in wastewater treatment plants were assessed as well as the trends and update on microplastic research in the South African aquatic ecosystem.

Comparative time-based intermediates study of ozone oxidation of 4-chloro- and 4-nitrophenols followed by LCMS-TOF.

Greater insights on the degradation pathways and intermediates formed during the oxidation of organics can be achieved by more suitable and compatible instrumentation. In our research, we sought to explore the relative advantages of the liquid chromatography coupled to a time of flight mass spectrometer (LCMS-TOF) technique for the comparative time-based degradation intermediates and pathways of 4-chlorophenol (4CP) and 4-nitrophenol (4NP). The ozonation of the analytes solution (100 mL of 2 x 10-3 M) was done in a sintered glass reactor, with an ozone dose of 0.14 mg min-1 (O2/O3 10 mL/min). The comparative oxidation results revealed that the 4-chloro- and 4-nitrocatechol pathways via hydroxylation were the major degradation route for 4CP and 4NP. Catechol intermediate was present as a primary breakdown product for the two analytes. Hydroquinone was observed as transient degradation intermediate for 4CP, but was absent for 4NP. Rather, a novel ozonation intermediate 2, 4-dinitrophenol was identified which was further oxidized to 3,6-dinitrocatechol. Several dimer products were identified in the oxidation processes, favored by alkaline conditions with more versatility shown by 4CP. The study provided a great insight into the ozone degradation intermediates and pathways, with some intermediates scarce in literature identified.

Multi-residue method for the determination of selected veterinary pharmaceutical residues in surface water around Livestock Agricultural farms.

A multi-residue method for the determination of the occurrence and prevalence levels of selected veterinary pharmaceutical residues in surface water was developed on a high performance liquid chromatography coupled to ultraviolet-visible (HPLC-UV) detector, and tested with the intent of profiling their distribution. The limit of detection (LOD) and limit of quantitation (LOQ) achieved for the selected pharmaceuticals; acetaminophen, diclofenac, salicylic acid, tetracycline, chloramphenicol, ciprofloxacin, bisphenol-A, 17ß-estradiol, estriol, and ivermectin ranged between 0.06-3.45 µg L-1 and 0.17-10.35 µg L-1 respectively. Other International Conference on Harmonization (ICH) parameters for validation of analytical procedures were also evaluated and discussed. Pharmaceutical residues were recovered from surface water samples collected from around livestock farms in Cape Town, South Africa by solid phase extraction (SPE), and thereafter separated and quantified using a validated method on a HPLC-UV-detector. Most frequently detected residues were: acetaminophen (56%), diclofenac (53), tetracycline (72%), 17ß-estradiol (73%); chloramphenicol (68%), and salicylic acid (67%), with significantly high (p > 0.05) spatial variability in the concentration distributions of the pharmaceuticals in the surface waters.

Determination of selected steroid hormones in some surface water around animal farms in Cape Town using HPLC-DAD.

In this study, a method for the simultaneous determination of two steroid hormones, 17ß-estradiol (E2) and estriol (E3), and a hormone mimicking polycarbonate, bisphenol-A (BPA), was developed and validated. This was thereafter used for the determination of the levels of the hormones in surface water collected around some livestock farms. The sensitivity of the method allowed the LODs and LOQs of the hormones and mimic hormone in the range 1.14-2.510 and 3.42-7.53 µg/L, respectively. The results revealed wide variability in the concentrations of E2 and E3, while BPA was not detected at any of the sampling stations. The concentration of E3 ranged between <1.14 and 45.5 µg/L (N = 120) in station 2 water. The highest concentration of E2 (15.7 µg/L, N = 80) was observed in water from station 1. The varied concentrations may be connected with the nature and sources of release, inconsistencies in analyte distribution due to dynamics of water flow pattern and the physical/chemical properties of the receiving water bodies.

Polycyclic Aromatic Hydrocarbons: A Critical Review of Environmental Occurrence and Bioremediation.

The degree of polycyclic aromatic hydrocarbon contamination of environmental matrices has increased over the last several years due to increase in industrial activities. Interest has surrounded the occurrence and distribution of polycyclic aromatic hydrocarbons for many decades because they pose a serious threat to the health of humans and ecosystems. The importance of the need for sustainable abatement strategies to alleviate contamination therefore cannot be overemphasised, as daily human activities continue to create pollution from polycyclic aromatic hydrocarbons and impact the natural environment. Globally, attempts have been made to design treatment schemes for the remediation and restoration of contaminated sites. Several techniques and technologies have been proposed and tested over time, the majority of which have significant limitations. This has necessitated research into environmentally friendly and cost-effective clean-up techniques. Bioremediation is an appealing option that has been extensively researched and adopted as it has been proven to be relatively cost-effective, environmentally friendly and is publicly accepted. In this review, the physicochemical properties of some priority polycyclic aromatic hydrocarbons, as well as the pathways and mechanisms through which they enter the soil, river systems, drinking water, groundwater and food are succinctly examined. Their effects on human health, other living organisms, the aquatic ecosystem, as well as soil microbiota are also elucidated. The persistence and bioavailability of polycyclic aromatic hydrocarbons are discussed as well, as they are important factors that influence the rate, efficiency and overall success of remediation. Bioremediation (aerobic and anaerobic), use of biosurfactants and bioreactors, as well as the roles of biofilms in the biological treatment of polycyclic aromatic hydrocarbons are also explored.

Bioremediation of polycyclic aromatic hydrocarbon (PAH) compounds: (acenaphthene and fluorene) in water using indigenous bacterial species isolated from the Diep and Plankenburg rivers, Western Cape, South Africa

Abstract This study was conducted to investigate the occurrence of PAH degrading microorganisms in two river systems in the Western Cape, South Africa and their ability to degrade two PAH compounds: acenaphthene and fluorene. A total of 19 bacterial isolates were obtained from the Diep and Plankenburg rivers among which four were identified as acenaphthene and fluorene degrading isolates. In simulated batch scale experiments, the optimum temperature for efficient degradation of both compounds was determined in a shaking incubator after 14 days, testing at 25 °C, 30 °C, 35 °C, 37 °C, 38 °C, 40 °C and 45 °C followed by experiments in a Stirred Tank Bioreactor using optimum temperature profiles from the batch experiment results. All experiments were run without the addition of supplements, bulking agents, biosurfactants or any other form of biostimulants. Results showed that Raoultella ornithinolytica, Serratia marcescens, Bacillus megaterium and Aeromonas hydrophila efficiently degraded both compounds at 37 °C, 37 °C, 30 °C and 35 °C respectively. The degradation of fluorene was more efficient and rapid compared to that of acenaphthene and degradation at Stirred Tank Bioreactor scale was more efficient for all treatments. Raoultella ornithinolytica, Serratia marcescens, Bacillus megaterium and Aeromonas hydrophila degraded a mean total of 98.60%, 95.70%, 90.20% and 99.90% acenaphthene, respectively and 99.90%, 97.90%, 98.40% and 99.50% fluorene, respectively. The PAH degrading microorganisms isolated during this study significantly reduced the concentrations of acenaphthene and fluorene and may be used on a larger, commercial scale to bioremediate PAH contaminated river systems.

Removal of PFOA and PFOS from aqueous solutions using activated carbon produced from Vitis vinifera leaf litter.

The removal of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) from aqueous solutions using agro-waste biomass of Vitis vinifera (grape) leaf litter was studied. Activated carbons were produced from the biomass and chemical activation achieved by using phosphoric acid (H3PO4) and potassium hydroxide (KOH) for the modification of the carbons' surface morphology. Activated carbons were characterized using Fourier transform infrared spectroscopy, scanning electron microscopy and Brunauer-Emmett-Teller (BET) in order to understand removal mechanisms of the contaminants by activated carbons. The effect of solution concentration, pH, adsorbent dosage, contact time and temperature was evaluated to optimize the removal efficiency of activated carbons. Adsorption isotherm models were used to analyse the equilibrium data obtained, and kinetic models were applied to study sorption mechanisms. The results fitted well into Freundlich isotherm with both AC-KOH and AC-H3PO4 having high K f values. Maximum adsorption capacities for AC-H3PO4 were 78.90 and 75.13 mg/g for PFOA and PFOS, respectively. Equilibrium was reached before 60 min on both adsorbents, and thermodynamic studies indicated that the process was exothermic and spontaneous. Surface morphology showed the abundance of microspores (>60%) with BET total surface area of 295.488 and 158.67 m2/g for AC-H3PO4 and AC-KOH activated carbons, respectively. Removal efficiencies were 95 and 90% for PFOA using AC-H3PO4 and AC-KOH, respectively; corresponding values for PFOS were 94 and 88%. Adsorbents' removal capacities depended on the physicochemical characteristics of adsorbents.

Bioremediation of polycyclic aromatic hydrocarbon (PAH) compounds: (acenaphthene and fluorene) in water using indigenous bacterial species isolated from the Diep and Plankenburg rivers, Western Cape, South Africa.

This study was conducted to investigate the occurrence of PAH degrading microorganisms in two river systems in the Western Cape, South Africa and their ability to degrade two PAH compounds: acenaphthene and fluorene. A total of 19 bacterial isolates were obtained from the Diep and Plankenburg rivers among which four were identified as acenaphthene and fluorene degrading isolates. In simulated batch scale experiments, the optimum temperature for efficient degradation of both compounds was determined in a shaking incubator after 14 days, testing at 25°C, 30°C, 35°C, 37°C, 38°C, 40°C and 45°C followed by experiments in a Stirred Tank Bioreactor using optimum temperature profiles from the batch experiment results. All experiments were run without the addition of supplements, bulking agents, biosurfactants or any other form of biostimulants. Results showed that Raoultella ornithinolytica, Serratia marcescens, Bacillus megaterium and Aeromonas hydrophila efficiently degraded both compounds at 37°C, 37°C, 30°C and 35°C respectively. The degradation of fluorene was more efficient and rapid compared to that of acenaphthene and degradation at Stirred Tank Bioreactor scale was more efficient for all treatments. Raoultella ornithinolytica, Serratia marcescens, Bacillus megaterium and Aeromonas hydrophila degraded a mean total of 98.60%, 95.70%, 90.20% and 99.90% acenaphthene, respectively and 99.90%, 97.90%, 98.40% and 99.50% fluorene, respectively. The PAH degrading microorganisms isolated during this study significantly reduced the concentrations of acenaphthene and fluorene and may be used on a larger, commercial scale to bioremediate PAH contaminated river systems.

Veterinary pharmaceuticals in aqueous systems and associated effects: an update.

Environmental studies have shown that pharmaceuticals can contaminate aqueous matrices, such as groundwater, surface water, sediment as well as aquatic flora and fauna. Effluents from sewage and wastewater treatment plants, pharmaceutical industries and hospitals have been implicated in such contamination. Recent studies have however revealed significant concentrations of pharmaceuticals in wastewater from animal facilities in proximal aquatic habitats. Furthermore, epidemiological studies have shown a consistent positive correlation between exposure to some drugs of veterinary importance and increased adverse effects in aquatic biota largely due to induction of endocrine disruption, antibiotic resistance, neurotoxicity, genotoxicity and oxidative stress. The aquatic habitats and associated biota are important in the maintenance of global ecosystem and food chain. For this reason, anything that compromises the integrity and functions of the aquatic environment may lead to major upset in the world's ecosystems. Therefore, knowledge about this route of exposure cannot be neglected and monitoring of their occurrence in the environment is required. This review focuses on scientific evidence that link the presence of pharmaceuticals in aqueous matrices to animal production facilities and presents means to reduce the occurrence of veterinary pharmaceutical residues in the aquatic habitats.

Benzo[a]pyrene and Benzo[k]fluoranthene in some processed fish and fish products.

In this study, the concentration levels of the probable carcinogenic PAH fractions, benzo[a]pyrene (BaP) and benzo[k]fluoranthrene (BkF) in fillets of some processed fish species were investigated. Fish species comprising Merluccius poli (hake), Tyrsites atun (snoek), Seriola lalandi (yellow-tail) and Brama brama (angel fish) were bought in fish shops at Gordon's Bay, Western Cape, South Africa. The fish were gutted, filleted and prepared for edibility by frying, grilling and boiling. Polycyclic aromatic hydrocarbons were extracted from each homogenized fish sample, cleaned-up using solid phase extraction (SPE), and analysed for the PAH fractions, BaP and BkF using a Gas Chromatograph coupled with a Flame Ionization Detector (GC-FID). The sum of the two PAHs (∑2PAH) i.e., BaP and BkF ranged between 0.56 and 1.46 µg/kg, in all boiled, grilled and fried fish species. The fried fish extracts showed significantly higher (p < 0.05) abundance of ∑2PAH, than grilled and boiled fish. Dietary safety and PAHs toxicity was also discussed.

Determination of polycyclic aromatic hydrocarbons [PAHs] in processed meat products using gas chromatography - flame ionization detector.

The concentrations of polycyclic aromatic hydrocarbons (PAHs) in smoked, grilled and boiled meats were determined using gas chromatography - flame ionization detector (GC-FID). PAHs in the processed meats were extracted in n-hexane after hydrolysis with methanolic KOH. Clean-up was achieved using solid phase extraction in neutral-Si/basic-Si/acidic-Si/neutral-Si frits. The fractions, benzo[k]fluoranthene (BkP), benzo[a]pyrene (BaP), indeno[123-cd]pyrene (IP) and benzo[ghi]perylene (BghiP) were separated and quantified using GC-FID. The method and instrument limits of detections were 0.1, 0.1, 0.2, 0.3µg/kg and 0.5, 0.5, 1.0, 1.5µg/kg, respectively, for BkP, BaP, IP and BghiP. The method's recovery and precision generally varied between 83.69% and 94.25% with relative standard deviation (RSD) of 3.18-15.60%; and 90.38-96.71% with relative standard deviation (RSD) of 1.82-12.87% respectively. The concentration of BkP, BaP, IP and BghiP in smoked, grilled and boiled meat samples were ranged 0.64-31.54µg/kg, 0.07-7.04µg/kg, 0.09-15.03, 0.51-46.67µg/kg and 0.01-5.11µg/kg, respectively.

Human exposure, biomarkers, and fate of organotins in the environment.

Organotin compounds result from the addition of organic moieties to inorganic tin.Thus, one or more tin-carbon bonds exist in each organotin molecule. The organo-tin compounds are ubiquitous in the environment. Organotin compounds have many uses, including those as fungicides and stabilizers in plastics, among others in industry. The widespread use of organotins as antifouling agents in boat paints has resulted in pollution of freshwater and marine ecosystems. The presence of organotin compounds in freshwater and marine ecosystems is now understood to be a threat, because of the amounts found in water and the toxicity of some organotin compounds to aquatic organisms, and perhaps to humans as well. Organotin com-pounds are regarded by many to be global pollutants of a stature similar to biphenyl,mercury, and the polychlorinated dibenzodioxins. This stature results from the high toxicity, persistence, bioaccumulation, and endocrine disruptive features of even very low levels of selected organotin compounds.Efforts by selected governmental agencies and others have been undertaken to find a global solution to organotin pollution. France was the first country to ban the use of the organotins in 1980. This occurred before the international maritime organization (IMO) called for a global treaty to ban the application of tributyltin (TBT)-based paints. In this chapter, we review the organotin compounds with emphasis on the human exposure, fate, and distribution of them in the environment. The widespread use of the organotins and their high stability have led to contamination of some aquatic ecosystems. As a result, residues of the organotins may reach humans via food consumption. Notwithstanding the risk of human exposure, only limited data are available on the levels at which the organotins exist in foodstuffs consumed by humans. Moreover, the response of marine species to the organotins, such as TBT, has not been thoroughly investigated. Therefore, more data on the organotins and the consequences of exposure to them are needed. In particular, we believe the following areas need attention: expanded toxicity testing in aquatic species, human exposure, human body burdens, and the research to identify biomarkers for testing the toxicity of the organotins to marine invertebrates.