Long-term decreases in persistent organic pollutants in South African coastal waters detected from beached polyethylene pellets

Microplastics in coral from three Mascarene Islands, Western Indian Ocean

Little is known about microplastics (MPs) in corals from the Indian Ocean. We compared MP concentrations, morphotypes, size, colours, and polymer compositions in six coral genera from three remote Mascarene islands (Rodrigues, St. Brandon's Atoll, and Agalega) of the Republic of Mauritius, on a 1200 km transect located in the South Equatorial Current (SEC). The mean MP concentration was 0.78 n/g (53 % fibres) with no significant differences between islands. Polymers were polypropylene (78 %) and polyethylene (18 %). We conclude that the SEC's MP concentrations and compositions have homogenized over thousands of kilometres across the Indian Ocean. We discuss the lack of hazardous polyurethane MPs in coral samples given obvious sources on St Brandon. To the best of our knowledge, this study is the first to report on MPs in coral from the Western Indian Ocean and the Mascarene Islands providing a baseline for further research, monitoring, mitigation, and policy development.

A Latest Review on Micro- and Nanoplastics in the Aquatic Environment: The Comparative Impact of Size on Environmental Behavior and Toxic Effect

Micro and nanoplastics (MNPs) have attracted growing global research attention due to their distinct environmental impacts, addressing escalating concerns. The diverse materials, sizes, and shapes of MNPs result in a range of environmental impacts. Size, a crucial characteristic of MNPs, influences their environmental behavior, affecting processes like migration, sedimentation, aggregation, and adsorption. Moreover, size modulates the biodistribution and toxicity of MNPs in aquatic organisms. This review delves into the comprehensive impacts of plastic size, with a primary focus on environmental behavior and toxic effects. Ultimately, this review emphasizes the ecological implications of MNP size, laying a foundation for future research in this field.

The Status of Marine Mussel Pollution Research in South Africa (2012-2022)

The growing human population requires more food each year, and seafood products can help meet this demand if clean water resources are available for their growth. Farmed and wild mussels are environmentally friendly seafood with many health benefits to human consumers, but they can also pose a health risk if they are harvested from areas where marine anthropogenic pollution is uncontrolled or unmonitored. While the coastline in South Africa has long been assumed to be pristine, a growing number of recent studies are raising contamination concerns. Baseline studies establish a wide range of anthropogenic pollutants to be present in the marine environment, specifically in urbanised or industrialised areas like major cities or harbours. This review summarises how mussels could pose health risks to human consumers and the current research that is being conducted by private researchers and institutions in South Africa. The review emphasises the need for more research in the field and for governmental pollution monitoring data to be released to the public.

Microplastic-sorbed persistent organic pollutants in coastal Mediterranean Sea areas of Tunisia

Microplastics (MPs) are emerging pollutants of global concern due to their pervasiveness, high sorption ability for persistent organic pollutants (POPs) and direct and indirect toxicity to marine organisms, ecosystems, as well as humans. As one of the major coastal interfaces, beaches are considered among the most affected ecosystems by MPs pollution. The morphological characteristics of MPs (pellets and fragments) collected from four beaches along the Tunisian coast and sorbed POPs, including polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs), were investigated in this study. The results showed that the MPs varied greatly in color, polymer composition and degradation degree. The color varied from colored to transparent and the most prevalent polymer identified using Raman spectroscopy was polyethylene. Scanning electron microscope (SEM) images exhibited various surface degradation features including cavities, cracks, attached diatom remains, etc. The concentrations of Σ12PCBs over all beaches ranged from 14 to 632 ng g-1 and 26 to 112 ng g-1 in the pellets and fragments, respectively, with a notable presence and dominance of highly-chlorinated PCBs such as CB-153 and -138. Among the OCPs, γ-HCH is the only compound detected with concentrations ranging from 0.4 to 9.7 ng g-1 and 0.7 to 4.2 ng g-1 in the pellets and fragments, respectively. Our findings indicate that MPs found on the Tunisian coast may pose a chemical risk to marine organisms as the concentrations of PCBs and γ-HCH in most of the analysed samples exceeded the sediment-quality guidelines (SQG), especially the effects range medium (ERM) and the probable effects level (PEL). As the first report of its kind, the information gathered in this study can serve as the baseline and starting point for future monitoring work for Tunisia and neighbouring countries, as well as for stakeholders and coastal managers in decision-making processes.

Organic Pollutants Associated with Plastic Debris in Marine Environment: A Systematic Review of Analytical Methods, Occurrence, and Characteristics

Plastic pollution has become one of the most serious environmental problems, and microplastics (MPs, particles < 5 mm size) may behave as a vehicle of organic pollutants, causing detrimental effects to the environment. Studies on MP-sorbed organic pollutants lack methodological standardization, resulting in a low comparability and replicability. In this work, we reviewed 40 field studies of MP-sorbed organic contaminants using PRISMA guidelines for acquiring information on sampling and analytical protocols. The papers were also scored for their reliability on the basis of 7 criteria, from 0 (minimum) to 21 (maximum). Our results showed a great heterogeneity of the methods used for the sample collection, MPs extraction, and instruments for chemicals' identification. Measures for cross-contamination control during MPs analysis were strictly applied only in 13% of the studies, indicating a need for quality control in MPs-related research. The most frequently detected MP-sorbed chemicals were polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), and organochlorine pesticides (OCPs). Most of the studies showed a good reliability (>75% of the total score), with 32 papers scoring 16 or higher. On the basis of the collected information, a standardizable protocol for the detection of MPs and MP-sorbed chemicals has been suggested for improving the reliability of MPs monitoring studies.

Beached microplastics at the Bahia Blanca Estuary (Argentina): Plastic pellets as potential vectors of environmental pollution by POPs

Microplastics (MPs) from the coastal areas of a highly anthropised estuary were sampled to assess their distribution in coastal sediments and their role as potential vectors of pollution. The average MP density was 1693 ± 2315 MPs/kg, which mainly accumulated in the high tide and storm berm areas of the beach. The Microplastic Pollution Index (MPPI), Microplastic Impact Coefficient (CMPI), Hierarchical Cluster Analysis and Principal Component Analysis revealed spatial variation in MPs pollution. High-density polyethylene plastic pellets were abundant at two beaches (192 ± 218 MPs/kg sediment). Furthermore, the presence of sorbed chemicals on pellets was assessed through GC-MS, showing 0.95 ± 0.09 ng/g of ∑7OCPs, 4.03 ± 0.89 ng/g of ∑7PCBs, 108.76 ± 12.88 ng/g of ∑16 PAHs and 122.79 ± 11.13 g/g of ∑29 PAHs. The sorption capacity of plastics, combined with their abundance, poses an environmental concern and also highlights their suitability as indicators of chemical exposure.

The role of seagrass meadows in the accumulation of microplastics: Insights from a South African estuary

Microplastics are widespread in marine ecosystems, where they threaten biota and human wellbeing. Seagrasses may act as natural filters of microplastics due to their particle trapping abilities, yet little is known about the extent of microplastics in the sediment of seagrass beds. The aim of this study was to compare microplastic accumulation in the sediments of Zostera capensis meadows with adjacent bare sediments at a small spatial scale (~5 km) in the Knysna estuary in South Africa. No significant difference in total microplastic counts were found between seagrass and unvegetated sediments. However, fibre microplastic counts differed significantly between the two locations at which samples were collected. This may be due to pollution levels and proximity to larger human population densities. Importantly, our study reveals variability in microplastic abundance and type even at small spatial scales, an important consideration for the design of future studies aiming to monitor for microplastics.

Persistent organic pollutants in sea bird eggs from the Indian Ocean's Mascarene Basin

We report the concentrations of persistent organic pollutants (POPs) in seabird eggs from St. Brandon's Atoll, a tropical island system in the western Indian Ocean. Ten eggs each of sooty terns (Onychoprion fuscatus), fairy terns (Gygis alba), and common noddies (Anous stolidus) were collected from the atoll. For a terrestrial reference, we analysed three feral chicken (Gallus gallus domesticus) eggs from the same location. Sooty tern eggs contained the highest mean concentrations of three chemical classes: ƩCHL₃ (0.21 ng/g wm; wet mass), ƩPCB₁₀ (1.5 ng/g wm), and ƩPBDE₆ (1.1 ng/g wm). Fairy tern eggs contained the highest mean concentrations of HCB (0.68 ng/g wm) and ƩCHB₅ (0.83 ng/g wm). The chicken eggs contained the highest mean concentrations of ƩDDT₃ (2.6 ng/g wm), while common noddy eggs contained the highest mean concentrations of ƩHCH₂ (0.5 ng/g wm). We surmise that the differences in chemical composition between species reflect different pollutant compositions in prey from the bird's different foraging ranges. The sooty terns foraging offshore contained higher POPs concentrations than the nearshore-foraging common noddies. Fairy tern eggs contained intermediate concentrations, commensurate with their intermediate foraging. Inter-island differences in contaminant concentrations were seen between eggs of the common noddies from St. Brandon's Atoll and Rodrigues Island, 520 km to the south-east. Concentrations of contaminants found in this study were lower than values quantified by other studies, making St. Brandon's Atoll an ideal reference site to monitor background concentrations of POPs in the tropical Indian Ocean.

Microplastics in sea surface waters around Scotland

This is the first regional, multi-annual assessment of floating microplastics in Scotland's seas. Sea surface samples were collected from 2014 to 2020, using a catamaran swimmer body/neuston net trawl and evaluated for the presence of microplastics. Microplastics were present in the surface waters of all Scottish Marine Regions (SMR) and Offshore Marine Regions (OMR) though almost 35% of sample sites contained no microplastics. Concentrations ranged from 0 to 91,128 microplastics km^-2 sea surface. Potential hotspots were identified in the Clyde (0-77,168 microplastics km^-2), Forth & Tay (0-83,729 microplastics km^-2) and the Solway (607-91,128 microplastics km^-2). Fragmented plastics accounted for almost 50% of the microplastics recovered and this may suggest that the microplastics in Scotland's seas are predominantly from the breakdown of larger items. Due to the variable geographic and temporal extents of the data it was not possible to carry out a trend assessment.

Deep seafloor plastics as the source and sink of organic pollutants in the northern South China Sea

Large plastic litter (as opposed to microplastics and plastic pellets) could adsorb organic pollutants and thus pose a serious threat to the marine environment. We report high levels of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) adsorbed to plastic litter sampled from depths of 1800-3100 m in the Xisha Trough region of the northern South China Sea (NSCS). ∑PCBs on plastics ranged from 126.9-142.1 ng/g, with tri-PCBs accounting for 92-97% of the total PCB concentrations in all samples. Levels of ∑OCPs varied from 4280 to 5351 ng/g (average 4690 ng/g), with a total of 19 compounds detected in the seven samples. While no parent DDT (dichlorodiphenyltrichloroethane) was detected, op'-DDE (metabolite of DDT) was most abundant, with concentrations ranging from 947.5-1551.7 ng/g. ∑CHLs (heptachlor + heptachlor epoxide A + heptachlor epoxide B + cis-chlordane + trans-chlordane) ranged from 1083.1-1263.7 ng/g (mean 1153 ng/g) and accounted for 24% of ∑OCPs. Various compositional ratios of HCH (hexachlorocyclohexane) and DDT metabolites improved our understanding of the sources and transport pathways of OCPs. The total absence of DDT may be a "ghost indicator" of no recent DDT inputs into the oceans. There could well be inputs of DDT, but only as the degraded metabolites DDE and DDD when they are adsorbed to seafloor plastic litter. A comparison of HCH isomer ratios in seafloor plastics with technical HCH ratios revealed that HCHs were possibly not from early residues but from later inputs. An ecological risk assessment of the contaminants indicated a high risk from ∑DDTs, p,p-DDE, and γ-HCH in all the sampled locations. Finally, we propose a descriptive model depicting the movements and transportation of PCBs and OCPs from the ocean surface to seafloor plastics in the NSCS.

Microplastics in African ecosystems: Current knowledge, abundance, associated contaminants, techniques, and research needs

Despite Africa ranking top in mismanaged plastic waste, there is insufficient data on the extent of microplastics and its interaction with other contaminants in its ecosystems. Microplastics pollution has been documented globally, however, specific data from the continent is crucial for accurate risk assessment and to drive policies. We critically reviewed 56 articles from 1987 to 2020 and provide an overview of the current knowledge of the abundance and distribution of microplastics and associated contaminants in African aquatic systems and organisms. Most of the studies were carried out in the marine environment and there is currently no available data on the abundance of microplastic pollution in the African terrestrial environment. We show that across all studies, 5-100% of all sampled aquatic organisms contained microplastics. Concerning high levels of microplastics were reported in fish from Egypt compared to other parts of Africa and the world. Across all persistent organic pollutants sampled in microplastics, hopanes and phthalates were present at high concentrations while sodium and zinc were high relative to other trace metals reported. The most frequently occurring plastics were polyethylene followed by polypropylene and polystyrene. We found that most of the studies relied on visual inspection (52%) > FTIR (38%) > Raman spectroscopy (5%) > Scanning electron microscopy (3%) > Differential scanning calorimetry (2%) for identifying microplastics. Major gaps in sampling and identification techniques which may have overestimated or underestimated the current levels were identified. We discuss other research priorities and recommend solutions to address these issues associated with microplastic pollution in Africa.

A Relevant Screening of Organic Contaminants Present on Freshwater and Pre-Production Microplastics

Microplastics (MPs) have recently been discovered as considerable pollutants of all environmental matrices. They can contain a blend of chemicals, some of them added during the manufacture of plastic to improve their quality (additives) and others adsorbed from the surrounding environment. In light of this, a detailed study about the identification and quantification of target organic pollutants and qualitative screening of non-target compounds present on MPs was carried out in different types of samples: environmental MPs, collected from an Italian river, and pre-production MPs, taken from the plastic industry. Polychlorobiphenyls (PCBs), organochlorine pesticides (OCPs), and polycyclic aromatic hydrocarbons (PAHs) were chosen as target compounds to be quantified by Gas Chromatography-Mass Spectrometry (GC–MS), while the non-target screening was carried out by High Resolution Gas Chromatography-Mass Spectrometry (HRGC–MS). The target analysis revealed concentrations of 16 priority Polycyclic Aromatic Hydrocarbons by Environmental Protection Agency (EPA-PAHs) in the range of 29.9–269.1 ng/g; the quantification of 31 PCBs showed values from 0.54 to 15.3 ng/g, identifying CB-138, 153, 180, 52, and 101 primarily; and the detected OCPs (p,p’-DDT and its metabolites) ranged between 14.5 and 63.7 ng/g. The non-target screening tentatively identified 246 compounds (e.g., phthalates, antioxidants, UV-stabilizers), including endocrine disruptors, toxic and reprotoxic substances, as well as chemicals subjected to risk assessment and authorisation. The large assortment of plastic chemicals associated with MPs showed their role as a presumable source of pollutants, some of which might have high bioaccumulation potential, persistence, and toxicity.

Impacts of plastic debris on biota and implications for human health: A South African perspective

Entanglement and ingestion of plastics are the main ecological impacts of marine plastic debris on marine biota, but indirect effects such as the transport of alien species and benthic smothering are also important to note. Entanglement of invertebrates, sharks, turtles, birds and marine mammals is mainly caused by macroplastics (>5 mm), and leads to reduced mobility, ineffective foraging and subsequent mortality. The main plastic types associated with entanglement are improperly discarded fishing nets, lines, ropes and straps. In South Africa and surrounding waters, plastic ingestion has been reported in a number of marine species: sharks (n=10), fish (n>=7), turtles (n=1) and birds (n=36). Lethal (macroplastic) and sub-lethal effects (microplastic ≤5 mm) of marine debris on biota have been noted, but at the time of this review there were no published reports on impacts at the population level. Consumed shellfish are possible vectors for the introduction of microplastics into humans. The specific impacts of microplastic ingestion on human health are largely unknown, but additives associated with plastics represent a threat. The research infrastructure in South Africa is insufficient to monitor and characterise marine plastic debris and, in many cases, not in line with global standards. More research effort is needed to understand the impacts of marine plastic debris on humans and marine biota in South Africa, particularly at the population level. Significance • Macroplastics affect marine biota mainly via entanglement and microplastics largely through ingestion. • Macro- and microplastic interactions with biota can result in sub-lethal effects and mortality but no population effects have been reported for South Africa. • Consumed shellfish are a potential source of microplastics for humans but their potential effects in humans remain unknown. • Better infrastructure is needed for improved monitoring and research on the effects of marine debris in South Africa.

Selectively enrichment of antibiotics and ARGs by microplastics in river, estuary and marine waters

The partition of antibiotics and antibiotic resistant genes (ARGs) between the microplastics (MPs) and the surrounding water with various salinity are still unclear. In this study, we hypothesized that adsorption of antibiotics on MPs might cause a significant change of the structure of microbial communities, diversity and abundance of ARGs on MPs and this might be further affected by change of salinity. In this study, we investigated adsorption of four common antibiotics (sulfamerazine, tetracycline, chloramphenicol and tylosin) to polyethylene (PE) MPs in river, estuary and marine waters, and the differences of antibiotic resistant genes (ARGs) and bacterial communities on MPs and in the three waters. The results showed that MPs can enrich antibiotics, ARGs and microbes from the surrounding water. Elevated salinity could reduce adsorption of antibiotics to MPs and the abundance of ARGs. For example, MPs can concentrate more antibiotics and ARGs in the fresh river water than in the estuary and the marine waters. In addition, ARGs and bacterial communities on MPs at various salinity were significantly different under the pressure of four antibiotics. On MPs, sul1, sulA/folP-01, tetA, tetC, tetX and ermE increased significantly but a few new ARGs such as sulA/folP-01 and tetA appeared. The structure of the bacterial communities on MPs was different from the surrounding water since some bacteria species found on MPs were barely detected in the surrounding water while some genera on MPs vanished after exposure to antibiotics. As the antibiotics adsorbed and the ARGs on MPs decreased with the water salinity, the structure of the communities on MPs thus varied with salinity change. These findings are important to understand the effects of MPs on the transport, fate and ecological risk of antibiotics and ARGs in different aquatic environments.

Persistent organic pollutants sorbed in plastic resin pellet - "Nurdles" from coastal areas of Central Chile

Plastic resin pellets were collected from coastal areas (n = 7) of central Chile. Pellets were analyzed using Fourier-transform infrared spectroscopy for polymer identification and gas chromatography-mass spectrometry for Persistent Organic Pollutants (POPs) determination. Screened compounds were PBDEs (n = 10), PCBs (n = 7), and OCPs (n = 13). Pellets were only found at Lenga Beach (San Vicente Bay), which is likely influenced by the presence of industrial activities in the surrounding coastal area. The diameter of the pellets was 4.0 ± 0.6 cm (n = 370), the color varied from white (32%) to yellowing (68%), and the most prevalent polymer identified was high-density polyethylene (99%). POPs concentrations (ng/g-pellet) ranged from 10 to 133 for Ʃ10PBDEs, from 3 to 60 for Ʃ7PCBs and between 0.1 and 7 for DDTs. Levels of POPs are consistent with other investigations around the world and highlight the sorbtion capacity of plastics resin pellets, and consequently transport of POPs into coastal environments.

Macrodebris and microplastics pollution in Nigeria: first report on abundance, distribution and composition

The abundance, distribution and composition of marine debris ( > 5 cm) and small microplastics (11 μm) from five rivers in South Eastern Nigeria was investigated. This study provided the first assessment of the type and quantity of marine litter and microplastics in Nigeria. A total of 3,487 macrodebris items/m² were counted with the following distribution: plastics (59%), metal (10%), cloth (7%), paper/cardboard (7%), rubber (7%), glass/ceramics (5%), medical and agro-based waste (3%), and wood (2%). The cleanliness of the river assessed with clean coast index ranged from “very clean” to “extremely dirty”. Microplastics abundance ranged from 440 to 1,556 particles/L, with high accumulation at downstream. Fragment shape was most abundant while fiber and film followed. The distribution of plastic types was PET (29%), PE (22%), PVC (16%), PP (14%), and others (6%). Significant relationship was found between the total abundances of microplastics and different macrodebris groups suggesting that microplastics were abundant in areas where the macrodebris abundance was high. Our results provide baseline information for future assessments. Management actions should focus on input prevention including proper waste management, recycling of plastics, and strict penalties for illegal dumping of wastes.

Sea-surface microplastic concentrations along the coastal shelf of KwaZulu-Natal, South Africa

Ocean pollution is a global issue; yet limited quantitative data on microplastic concentrations are available for the South African coastal shelf. Estuarine outlets within industrial areas that are found along the coastline serve as conduits for plastics and other pollutants to the ocean. This study investigated coastal plastic concentrations around KwaZulu-Natal. Forty-three manta trawl samples were collected and analysed over a period of one year. An average of 4.01 ± 3.28 plastic particles/100 m² was found in surface trawls. Plastic concentrations in winter were significantly higher than those in summer (5.54 ± 3.26 and 2.96 ± 2.94 particles/100 m² respectively). The highest concentrations of plastics were found south of the city of Durban, with the highest concentration at Isipingo winter with 12.2 particles/100 m². Among the summer samples, the highest concentration of particles was off Amanzimtoti (9.54 particles/100 m²). The main plastic forms were fragments, films and fibres that were commonly white, clear, opaque, blue and black in colour. High plastic concentrations in the Durban area and sites close-by were expected due to the high levels of urbanization in the area, however, the difference in concentrations found between winter and summer was not expected and may have been due to the prevailing wind and/or current conditions on the sampling date.

Occurrence and risk evaluation of organochlorine contaminants in surface water along the course of Swartkops and Sundays River Estuaries, Eastern Cape Province, South Africa

Organochlorine contaminants were analysed in surface water from Sundays (SDE) and Swartkops Estuaries (SWE), Eastern Cape Province, which is among the largest estuaries in South Africa. The concentration of Σ₁₈OCPs ranged from 16.7 to 249.2 ng/L in autumn, 19.9-81.4 ng/L in winter, 43.6-126.8 ng/L in spring and 68.3-199.9 ng/L in summer for SDE, whereas in SWE, the values varied from 20.9 to 259.7 ng/L in autumn, 58.9-263.9 ng/L in winter, 3.2-183.6 ng/L in spring and 118.0-188.9 ng/L in summer. Among all OCPs, α-HCH, β-HCH, p,p'-DDE, p,p'-DDT, endrin, dieldrin and endrin aldehyde were predominant in surface water samples from SDE and SWE. Furthermore, the mean concentration of polychlorinated biphenyls (PCBs) ranged from 126.7 ng/L in winter to 151.0 ng/L in spring for SDE and 249.0 ng/L in spring to 727.6 ng/L in winter for SWE. Tri- and tetra-PCBs dominated the PCB homologue profile. Hierarchical cluster analysis grouped the study sites into three regions from least polluted to most polluted, indicated that SWE is more polluted compared to SDE, probably due to the influx of agricultural and industrial effluents. Carcinogenic and non-carcinogenic risk assessment revealed that the water from both estuaries is not safe for drinking, although suitable for bathing.

Profiles of bacterial assemblages from microplastics of tropical coastal environments

Plastic waste is a global issue of an increasing concern in aquatic ecosystems. Microplastics form a large proportion of plastic pollution in marine environments. Although microplastics are prevalent, their distribution along the coasts of tropical regions is not well studied. Microplastic pieces (1-5 mm) were collected from two distinct regions along the coastlines of Singapore, from the northern coast in the Johor Strait and the southern coast in the Singapore Strait. Microplastics were present in concentrations ranging from 9.20-59.9 particles per kg of dry sand sediment. The majority of microplastics identified were foam particles (55%) and fragments (35%). Microplastics were significantly more abundant on heavily populated beaches compared to pristine beaches. High throughput sequencing was used to profile the communities of bacteria on the surfaces of microplastic particles. The structure of the microbial communities was primarily characterised by Proteobacteria and Bacteroidetes and were distinct across sites. Hydrocarbon-degrading genera such as Erythrobacter were dominant in areas with heavy shipping and pollution. Potential pathogenic genera such as Vibrio and Pseudomonas were also identified. This study highlights the diverse bacterial assemblages present on marine microplastic surfaces and the importance of understanding the bacterial plastisphere.

The state of POPs in Ghana- A review on persistent organic pollutants: Environmental and human exposure

Ghana is one of the top pesticide users and highest persistent organic pollutant (POP) emitters in sub-saharan Africa. Despite recent increases in published data, there is limited information on how POP concentrations have changed, post ratification of the Stockholm Convention. As a result, this review aims to address these knowledge gaps by collating available data that reported POPs in Ghanaian environmental matrices, identify spatial and temporal trends, and establish potential health risks. It is worth noting that Ghana has not developed its own regulatory standards for POPs, but adapts United States Environmental Protection Agency (USEPA) standards. Results obtained showed concentrations in excess of USEPA regulatory standards for per- and poly-fluoroalkyl sulphonates (PFASs) and dichlorodiphenyldichloroethane (DDD) in water, polychlorinated and polybrominated dibenzo-p-dioxins and furans (PCDD/Fs and PBDD/Fs) in e-waste soils, and polybrominated diphenyl ethers in aquatic organisms and dairy products. The published studies do not cover major regions nationwide. The inconsistency in methods and analytes measured, along with data scarcity in some regions, makes it challenging to identify temporal trends. However, the data did indicate decreasing concentrations of some legacy POPs in soil/sediment and aquatic organisms, with increasing concentrations of some POPs in water, fish, fruits and vegetables. Studies that performed health risks assessments were limited although the data indicated risks to e-waste workers, some farmers and vulnerable sub-populations. This review identified potential human health risks from POPs in the Ghanaian environment and the need for more consistent and widespread monitoring program.

Imposex assessment and tributyltin levels in sediments along the Atlantic coast of South Africa

Female marine gastropods develop imposex (growth of penis/vas deferens) when exposed to TBT (tributyltin). Ours, is the first report of an imposex survey associated with TBT in sediment along 920 km of South Africa's Atlantic coastline. We sampled and analysed 1389 individuals of 13 caenogastropod species, and sediment samples from 25 sites, presumed impacted and not impacted by TBT pollution. Imposex was detected in six species not previously reported to suffer from this phenomenon, at eight sites, with up to 100% of females affected. Butyltins were found at quantifiable concentrations at four sites, with TBT and DBT (dibutyltin) concentrations in sediments up to 20 000 μg/kg dry mass (dm) and 3740 μg/kg dm, respectively. These findings are of major concern considering that TBT has been banned globally since 2008 by the International Maritime Organisation (IMO) - more extensive research is required in areas affected by TBT and where aquaculture is present.

Interaction of toxic chemicals with microplastics: A critical review

Occurrence of microplastics (MPs) in the environment has attracted great attention as it has become a global concern. This review aims to systematically demonstrate the role of marine microplastic as a novel medium for environmental partitioning of chemicals in the ocean, which can cause toxic effects in the ecological environment. This review assimilated and analyzed available data published between 1972 and 2017 on the interaction between MPs and selected chemicals. Firstly, the review analyzes the occurrence of chemicals in MPs and outlines their distribution patterns. Then possible mechanisms of the interaction between MPs and organic chemicals and potential controlling factors were critically studied. Finally, the hazards of MPs and affiliated organic chemicals to marine organisms were shortly summarized.

Characterization of plastic debris and association of metals with microplastics in coastline sediment along the Persian Gulf

This study reports number, size and color distribution, and metal contents of microplastics as well as adherent sediments along the Persian Gulf. Samples were collected from 9 stations in summer 2015 with a sampling time interval of 10 days. Plastic size of 2-5 mm, and ≤0.25 mm with 45 and 33% and white and colorless plastics with 62 and 33% had the highest abundance considering number per m², respectively. In general, the majority of collected plastics (79%) were smaller than 5 mm (defined size for microplastics). The mean Al, Fe, Mn, Cd, Cr, Ni, Pb, Cu contents of plastic fragments were 115, 531, 32.2, 0.035, 0.915, 2.03, 4.59, and 3.6 μg g^-1, respectively while the mean Al, Fe, Mn, Cd, Cr, Ni, Pb, Cu contents of sediments were 186, 3050, 127, 0.81, 5.01, 14.5, 48.6 and 5.43 μg g^-1 respectively. There were significant differences between the abundance of plastic items as well as the all examined metal concentrations of microplastics and sediments at different sampling times. As there is no regular cleanup program in the studied areas, significant differences between plastic items number at different sampling times (with higher plastic items number at the first day of sampling) showed that a large number of plastic items may enter from beaches to the sea and become available to marine organisms.

Sinks and sources: Assessing microplastic abundance in river sediment and deposit feeders in an Austral temperate urban river system

Microplastics are important novel pollutants in freshwaters but their behaviour in river sediments is poorly understood due to the large amounts of coloured dissolved organic matter that impede sample processing. The present study aimed to 1.) estimate the microplastic pollution dynamics in an urban river system experiencing temporal differences in river flow, and 2.) investigate the potential use of chironomids as indicators of microplastic pollution levels in degraded freshwater environments. Microplastic levels were estimated from sediment and Chironomus spp. larvae collected from various sites along the Bloukrans River system, in the Eastern Cape South Africa during the summer and winter season. River flow, water depth, channel width, substrate embeddedness and sediment organic matter were simultaneously collected from each site. The winter season was characterised by elevated microplastic abundances, likely as a result of lower energy and increased sediment deposition associated with reduced river flow. In addition, results showed that particle distribution may be governed by various other external factors, such as substrate type and sediment organic matter. The study further highlighted that deposit feeders associated with the benthic river habitats, namely Chironomus spp. ingest microplastics and that the seasonal differences in sediment microplastic dynamics were reflected in chironomid microplastic abundance. There was a positive, though weakly significant relationship between deposit feeders and sediment suggesting that deposit feeders such as Chironomus spp. larvae could serve as an important indicator of microplastic loads within freshwater ecosystems.

Blood concentrations of PCBs and DDTs in an avian predator endemic to southern Africa: Associations with habitat, electrical transformers and diet

Persistent pollutants such as organochlorine compounds (OCs) have been highlighted as a cause of population decline in avian predators. Understanding patterns of OCs contamination can be crucial for the conservation of affected species, yet little is known on these threats to African raptors. Here we report on OC concentrations in an endangered predator endemic to southern Africa, the Black Harrier Circus maurus. Blood samples were collected in 2012-2014 from wild nestlings (n = 90) and adults (n = 23) in south-western South Africa, where agriculture and urbanization have developed rapidly since the 1950s. Polychlorinated biphenyl (ΣPCB) and dichlorodiphenyltrichloroethane (ΣDDT, for p,p'-DDT + p,p'-DDE) were detected in 79% and 84% of sampled individuals, respectively, with varying concentrations among demographic groups: nestlings had significantly higher ΣPCB and p,p'-DDT concentrations than adults, while adults had higher levels of p,p'-DDE than nestlings. Levels of ΣPCB significantly increased with an index of electric transformer density, a measure of the number and power of electric transformers around active nests. We propose this index as a useful tool for assessing ΣPCB exposure risk in other wildlife. Levels of p,p'-DDE significantly increased with the proportion of wetlands within the breeding territory, and also with the proportion of bird biomass in the diet. No association was found between OC levels and the protected area status of nesting sites. Physiological effects of contaminants were also manifest in increased white blood cell counts with higher p,p'-DDT levels. Heterophil to lymphocyte ratio increased with higher ΣPCB levels, suggesting increased physiological stress and reduced immunity in contaminated individuals. Our results suggest that OCs are still a current cause of concern for endangered Black Harriers, as well as other sympatric predators.

Petroleum Hydrocarbon Profiles of Water and Sediment of Algoa Bay, Eastern Cape, South Africa

Petroleum hydrocarbon profiles of water and sediment samples of Algoa Bay in the Eastern Cape Province of South Africa were assessed using standard analytical procedures. Water (from surface and bottom levels) and sediment samples were collected from five locations in the bay from February to June 2016. Extraction of the petroleum hydrocarbons from the water and sediment samples collected was achieved using liquid-liquid and Soxhlet extraction techniques, respectively, followed by column clean up. Target compounds were analytically determined with gas chromatography-flame ionization detector (GC-FID) and quantified by integrating the areas of both the resolved and unresolved components. Physicochemical properties of the water samples were also determined on site using a SeaBird 19plusV2 CTD SBE 55 device. Estimated limit of detection, limit of quantitation and relative standard deviation for the 35 n-alkane standards ranged from 0.06 to 0.13 μg/L, 0.30 to 0.69 μg/L and 3.61 to 8.32%, respectively. Results showed that total petroleum hydrocarbon (TPH) varied from 45.07 to 307 μg/L in the water and 0.72 to 27.03 mg/kg in the sediments. The mean concentrations of TPH in both the water and sediment samples from Algoa Bay revealed a slight level of pollution. The diagnostic indices used showed that the hydrocarbons in the area were from both biogenic and anthropogenic sources. Hence, there is need for adequate regulation and control of all activities contributing to the levels of petroleum hydrocarbon in the marine environment for the safety of human, aquatic and wild lives in the area.

Colour spectrum and resin-type determine the concentration and composition of Polycyclic Aromatic Hydrocarbons (PAHs) in plastic pellets

This study assessed the concentration and composition of Polycyclic Aromatic Hydrocarbons (PAHs) in plastic pellets, collected from sandy beaches and considered different resin and colour tones. Results showed that polyethylene pellets, while displaying a greater range of total PAH concentrations did not differ significantly from polypropylene pellets. More importantly, both resin types demonstrated predictable increases in total PAH across a spectrum of darkening colour tones. Multivariate comparisons of 36 PAH groups, further showed considerable variability across resin type and colour, with lighter coloured pellets comprising lower molecular weight, while darker pellets contained higher weight PAHs. Overall, we show predictable variation in PAH concentrations and compositions of plastic pellets of different ages and resin types that will directly influence the potential for toxicological effects. Our findings suggest that monitoring programs should take these attributes into account when assessing the environmental risks of microplastic contamination of marine and coastal habitats.

Marine and freshwater microplastic research in South Africa

South Africa has a vibrant plastics manufacturing industry, but recycling is limited and insufficient with a notable proportion of the unmanaged waste entering the environment. South Africa is a developing country with microplastics research in its inception. Very little is known about freshwater microplastics, and studies on South African marine microplastics are limited but actively being pursued. In a water-scarce country, protection of freshwater resources remains a priority, but in the face of other socioeconomic issues (poverty, unemployment, and HIV/AIDS), it receives insufficiently effective attention. The full impact and risks of microplastics pollution in water is yet to be discovered. The risks may be enhanced in a developing country where many communities remain largely dependent on the land and natural waters. With South Africa being a water-scarce country, the quality of its aquatic resources is at an even greater risk with an assumed increasing background of microplastics, emphasizing the need for further research. A South African Water Research Commission-funded project is being undertaken to derive research priorities, but there is an immediate need for improved recycling and waste management. Integr Environ Assess Manag 2017;13:533-535. © 2017 SETAC.

Temporal and spatial changes in persistent organic pollutants in Vietnamese coastal waters detected from plastic resin pellets

Plastic resin pellets collected at Minh Chau island and Ba Lat estuary between 2007 and 2014 in Vietnam were analyzed for dichloro-diphenyl-trichloroethanes (DDTs), polychlorinated biphenyls (PCBs) and hexachlorocyclohexanes (HCHs). The study was carried out as part of the International Pellet Watch program for monitoring the global distribution of persistent organic pollutants (POPs). Higher levels of DDTs compared to PCBs indicated agricultural inputs rather than industrial discharges in the region. Most POP concentrations on both beaches decreased over the period, with the exception of HCH isomers. Though the concentration of DDTs showed a drastic decline on both beaches between 2007/2008 and 2014, DDTs accounted for 60-80% of total DDTs, suggesting that there is still a fresh input of these chemicals in the region. This study strongly recommends further investigations to track temporal and spatial patterns of POP levels in the marine environment using plastic resin pellets.

Spatial variability in persistent organic pollutants and polycyclic aromatic hydrocarbons found in beach-stranded pellets along the coast of the state of São Paulo, southeastern Brazil

High spatial variability in polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), organochlorine pesticides, such as DDTs, and polybrominated diphenylethers was observed in plastic pellets collected randomly from 41 beaches (15 cities) in 2010 from the coast of state of São Paulo, southeastern Brazil. The highest concentrations ranged, in ng g(-1), from 192 to 13,708, 3.41 to 7554 and <0.11 to 840 for PAHs, PCBs and DDTs, respectively. Similar distribution pattern was presented, with lower concentrations on the relatively less urbanized and industrialized southern coast, and the highest values in the central portion of the coastline, which is affected by both waste disposal and large port and industrial complex. Additional samples were collected in this central area and PCB concentrations, in ngg(-)(1), were much higher in 2012 (1569 to 10,504) than in 2009/2010 (173 to 309) and 2014 (411), which is likely related to leakages of the PCB commercial mixture.

Profiling and Spatial Variation Analysis of Persistent Organic Pollutants in South African Delphinids

The continuous disposal of persistent organic pollutants (POPs) in South Africa (SA) warrants concern about their detrimental effects on humans and wildlife. We surveyed six dolphin species (n = 90) incidentally captured in shark net installations or stranded off the SA east and south coast from 2005 to 2009 to study the POP exposure. Sousa plumbea, an inshore and estuarine species, was found to be the most contaminated by total POPs (21 100 ng g(-1) lw) of all the dolphins off SA, followed by Tursiops aduncus (19 800 ng g(-1) lw), Lagenodelphis hosei (13 600 ng g(-1) lw), and Delphinus capensis (5500 ng g(-1) lw), whereas POP levels in the offshore or pelagic delphinids were much lower. In all delphinids, dominant pollutants were dichlorodiphenyltrichloroethanes (DDTs), which represented more than 60% of the total concentration of total POPs, followed by polychlorinated biphenyls (PCBs, 30%). Concentrations of DDTs in S. plumbea and T. aduncus off SA were among the highest levels reported in delphinids globally. Approximately half of the adult T. aduncus had PCB concentrations above the effect threshold for impairment of immune functions. The concentrations of Mirex and Dieldrin in SA delphinids were higher than those found in species from other regions of the Southern Hemisphere.

The flip-or-flop boutique: Marine debris on the shores of St Brandon's rock, an isolated tropical atoll in the Indian Ocean

Isolated coral atolls are not immune from marine debris accumulation. We identified Southeast Asia, the Indian sub-continent, and the countries on the Arabian Sea as most probable source areas of 50 000 items on the shores of St. Brandon's Rock (SBR), Indian Ocean. 79% of the debris was plastics. Flip-flops, energy drink bottles, and compact fluorescent lights (CFLs) were notable item types. The density of debris (0.74 m(-)(1) shore length) is comparable to similar islands but less than mainland sites. Intact CFLs suggests product-facilitated long-range transport of mercury. We suspect that aggregated marine debris, scavenged by the islands from currents and gyres, could re-concentrate pollutants. SBR islets accumulated debris types in different proportions suggesting that many factors act variably on different debris types. Regular cleaning of selected islets will take care of most of the accumulated debris and may improve the ecology and tourism potential. However, arrangements and logistics require more study.

Plastic pollution in five urban estuaries of KwaZulu-Natal, South Africa

Monitoring plastic concentrations in estuaries is vital in assessing the magnitude of terrestrial inputs to oceanic environments. Data on plastics ≤ 5 mm in estuaries are scant. This study determined microplastic levels within five estuaries along the Durban coastline and on intervening beaches. Plastics were isolated from estuarine sediment, beach sediment and the surface water of each estuary and characterised. Sediment at the Bayhead area of Durban harbour had the highest average plastic concentrations (745.4 ± 129.7 particles per 500 ml) and an attenuating concentration trend away from the city centre was found. Prevailing south to north longshore drift was hypothesised to result in plastic accumulation on the northern shores of beaches with estuarine effluents, however, this was not found. Fragments composed the largest percent of plastics (59%) found in Bayhead, whereas fibres dominated other estuaries with proportions ranging from 38% of total plastics in the uMgeni estuary to 66% in the Mdloti.

Microplastics in sediments: A review of techniques, occurrence and effects

Microplastics are omnipresent in the marine environment and sediments are hypothesized to be major sinks of these plastics. Here, over 100 articles spanning the last 50 year are reviewed with following objectives: (i) to evaluate current microplastic extraction techniques, (ii) to discuss the occurrence and worldwide distribution of microplastics in sediments, and (iii) to make a comprehensive assessment of the possible adverse effects of this type of pollution to marine organisms. Based on this review we propose future research needs and conclude that there is a clear need for a standardized techniques, unified reporting units and more realistic effect assessments.

Multidecadal Field Data Support Intimate Links between Phytoplankton Dynamics and PCB Concentrations in Marine Sediments and Biota

We analyzed three decades of field observations in the North Sea with additive models to infer spatiotemporal trends of chlorophyll a concentration, sediment organic carbon content, and polychlorinated biphenyls (PCBs) concentrations in mussels and sediments. By doing so, we separated long-term changes in PCB concentrations from seasonal variability. Using the inferred seasonal variability, we demonstrated that phytoplankton blooms in spring and autumn correspond to the annual maxima of the organic carbon content (r = 0.56; p = 0.004) and the PCB concentrations in sediments (r = 0.57; p = 0.004). Furthermore, we found a negative correlation between the PCB concentrations in sediments and in blue mussels (Mytilus edulis; r = -0.33, p = 0.012), which is probably related to the cleansing of the dissolved PCB phase driven by sinking organic matter during phytoplankton blooms and the filter-feeding behavior of the blue mussel. The present research demonstrates the role of seasonal phytoplankton dynamics in the environmental fate of PCBs at large spatiotemporal scales.

Bimonthly variability of persistent organochlorines in plastic pellets from four beaches in Mumbai coast, India

Organochlorines (OCs) such as polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) were analysed in plastic pellets collected from four beaches of Mumbai coast bimonthly from May 2011 to March 2012. A total of 72 pools of pellets were extracted and analysed by gas chromatograph equipped with a Ni(63) electron capture detector (ECD). The median concentrations of seven ΣPCBs and 16 ΣOCPs were 37.08 and 104.90 ng g(-1) (n = 72), respectively. PCB-28 was recorded at the highest concentration with a mean of 17.58 ± 2.77 ng g(-1) among the seven PCBs studied, followed by PCB-52 and PCB-101. Bimonthly variation was significant for ΣPCBs. The ΣPCB concentration in November was at par with that of September and was significantly higher than those of the other months (p < 0.05) with an increasing trend during the monsoon period. Among the OCPs, γ-HCH recorded the highest concentration with a mean of 33.88 ± 5.97 ng g(-1) followed by heptachlor and α-HCH. The ΣOCPs and ΣHCHs are not significantly varied among the months and sites. However, significant variation was observed for ΣDDTs among the months and sites (p < 0.05). The significantly higher concentration of ΣDDT (46.55 ± 12.23 ng g(-1)) was found in January than in the other months while it was intermediate in November. The study confirmed that plastic pellets are a trap for various cyclodine compounds in addition to PCB, HCH and DDT. Further, pellets can be used to study the temporal variability for a range of organic micropollutants.

Chlorinated, brominated and fluorinated organic pollutants in African Penguin eggs: 30 years since the previous assessment

The African Penguin population has drastically declined over the last 100 years. Changes in food availability due to over-fishing and other oceanographic changes seem to be major causes. However, it has also been 30 years since organic pollutants as a potential factor have been assessed. We analysed penguin eggs collected in 2011 and 2012 from two breeding colonies 640 km apart: Robben Island near Cape Town on the Atlantic Ocean coast, and Bird Island near Port Elizabeth on the Indian Ocean coast of South Africa. We quantified organochlorine pesticides, brominated flame retardants, and perfluorinated compounds (PFCs). Compared to 30 years ago, concentrations of ΣDDT have remained about the same or slightly lower, while ΣPCBs declined almost four-fold. The use of DDT in malaria control is unlikely to have contributed. PFCs were detected in all eggs. Indications (non-significant) of eggshell thinning associated with ΣDDT and ΣPCB was found. It seems therefore that the concentrations of measured organic pollutants the African Penguin eggs are not contributing directly to its current demise, but concerns remain about thinner shells and desiccation. Effects of combinations of compounds and newer compounds cannot be excluded, as well as more subtle effects on reproduction, development, and behaviour.

Distribution of polychlorinated biphenyl residues in sediments and blue mussels (Mytilus galloprovincialis) from Port Elizabeth Harbour, South Africa

Sediment and Mytilus galloprovincialis samples collected from the Port Elizabeth Harbour were analysed for six indicator PCB congeners to assess their contamination status. The concentrations of total PCBs in sediments and M. galloprovincialis ranged from 0.56 to 2.35 ng/g dry weight and 14.48 to 21.37 ng/g wet weight, respectively. Congeners 138 and 153 were dominant and accounted for an average of 29% and 24% of total PCBs in M. galloprovincialis; 32% and 30% in sediments, respectively. Sediments are home to a wide variety of aquatic life. None of the sediments analysed exceeded the PCB limits recommended the Canadian interim sediment quality guideline and the South African recommended sediment guidelines (21.6 ng/g). Both humans and aquatic life are sensitive to the toxic effects of PCBs.

Protected areas in the Atlantic facing the hazards of micro-plastic pollution: first diagnosis of three islands in the Canary Current

Coastal zones and the biosphere as a whole show signs of cumulative degradation due to the use and disposal of plastics. To better understand the manifestation of plastic pollution in the Atlantic Ocean, we partnered with local communities to determine the concentrations of micro-plastics in 125 beaches on three islands in the Canary Current: Lanzarote, La Graciosa, and Fuerteventura. We found that, in spite of being located in highly-protected natural areas, all beaches in our study area are exceedingly vulnerable to micro-plastic pollution, with pollution levels reaching concentrations greater than 100 g of plastic in 1l of sediment. This paper contributes to ongoing efforts to develop solutions to plastic pollution by addressing the questions: (i) Where does this pollution come from?; (ii) How much plastic pollution is in the world's oceans and coastal zones?; (iii) What are the consequences for the biosphere?; and (iv) What are possible solutions?

Additive modelling reveals spatiotemporal PCBs trends in marine sediments

We developed generalised additive mixed models (GAMMs) to infer spatiotemporal trends of environmental PCB concentrations from an extensive dataset (n=1219) of PCB concentrations measured between 1991 and 2010 in sediments of the Belgian Coastal Zone (BCZ) and the Western Scheldt estuary. A GAMM with time, geographical zone, periodicity and the organic carbon - water partition coefficient as covariates explained 49% of the variability in the log transformed PCB sediment concentrations. The time trends unraveled two to threefold PCB concentration decreases in the BCZ during the last 20 years. However, in the Western Scheldt estuary, time trends were spatially heterogeneous and not significantly decreasing. These results demonstrate that international efforts to cut down emissions of PCBs have been effective to reduce concentrations in open water ecosystems like the BCZ but had little effect in the urbanised and industrialised area of the Scheldt estuary.

The present and future of microplastic pollution in the marine environment

Recently, research examining the occurrence of microplastics in the marine environment has substantially increased. Field and laboratory work regularly provide new evidence on the fate of microplastic debris. This debris has been observed within every marine habitat. In this study, at least 101 peer-reviewed papers investigating microplastic pollution were critically analysed (Supplementary material). Microplastics are commonly studied in relation to (1) plankton samples, (2) sandy and muddy sediments, (3) vertebrate and invertebrate ingestion, and (4) chemical pollutant interactions. All of the marine organism groups are at an eminent risk of interacting with microplastics according to the available literature. Dozens of works on other relevant issues (i.e., polymer decay at sea, new sampling and laboratory methods, emerging sources, externalities) were also analysed and discussed. This paper provides the first in-depth exploration of the effects of microplastics on the marine environment and biota. The number of scientific publications will increase in response to present and projected plastic uses and discard patterns. Therefore, new themes and important approaches for future work are proposed.

Monitoring of a wide range of organic micropollutants on the Portuguese coast using plastic resin pellets

We analyzed polychlorinated biphenyls (PCBs), dichlorodiphenyl dichloroethane and its metabolites, hexachlorocyclohexanes (HCHs), polycyclic aromatic hydrocarbons (PAHs), and hopanes, in plastic resin pellets collected from nine locations along the Portuguese coast. Concentrations of a sum of 13 PCBs were one order of magnitude higher in two major cities (Porto: 307 ng/g-pellet; Lisboa: 273 ng/g-pellet) than in the seven rural sites. Lower chlorinated congeners were more abundant in the rural sites than in the cities, suggesting atmospheric dispersion. At most of the locations, PAH concentrations (sum of 33 PAH species) were ∼100 to ∼300 ng/g-pellet; however, three orders of magnitude higher concentrations of PAHs, with a petrogenic signature, were detected at a small city (Sines). Hopanes were detected in the pellets at all locations. This study demonstrated that multiple sample locations, including locations in both urban and remote areas, are necessary for country-scale pellet watch.