Antifouling paint booster biocides (Irgarol 1051 and diuron) in marinas and ports of Bushehr, Persian Gulf

Assessing the spatiotemporal occurrence and ecological risk of antifouling biocides in a Brazilian estuary

Diuron and Irgarol are common antifouling biocides used in paints to prevent the attachment and growth of fouling organisms on ship hulls and other submerged structures. Concerns about their toxicity to non-target aquatic organisms have led to various restrictions on their use in antifouling paints worldwide. Previous studies have shown the widespread presence of these substances in port areas along the Brazilian coast, with a concentration primarily in the southern part of the country. In this study, we conducted six sampling campaigns over the course of 1 year to assess the presence and associated risks of Diuron and Irgarol in water collected from areas under the influence of the Maranhão Port Complex in the Brazilian Northeast. Our results revealed the absence of Irgarol in the study area, irrespective of the sampling season and site. In contrast, the mean concentrations of Diuron varied between 2.0 ng L-1 and 34.1 ng L-1 and were detected at least once at each sampling site. We conducted a risk assessment of Diuron levels in this area using the risk quotient (RQ) method. Our findings indicated that Diuron levels at all sampling sites during at least one campaign yielded an RQ greater than 1, with a maximum of 22.7, classifying the risk as "high" based on the proposed risk classification. This study underscores the continued concern regarding the presence of antifouling biocides in significant ports and marinas in Brazilian ports, despite international bans.

Current Status of Antifouling Biocides Contamination in the Seto Inland Sea, Japan

A monitoring survey of antifouling biocides was conducted in the Harima Nada Sea and Osaka Bay of the Seto Inland Sea, Japan to assess contamination by organotin (OT) compounds and alternative biocides. The concentrations of tributyltin (TBT) compounds in surface water ranged from 1.0 to 2.8 ng/L, and the detected TBT concentrations in the bottom water layer were higher than those in the surface water. The concentrations of TBT compounds in sediment samples ranged from 2.0 to 28 ng/g dry weight (dw), respectively. The concentrations of alternative biocides in the water and sediment were lower than those before the banning of TBT by the International Maritime Organization (IMO). Although triphenyltin (TPT) compounds were not detected in water samples, TPT compounds were detected in the range of < 0.1-2700 ng/g dw in sediment samples. Their concentrations in the water samples were as follows: diuron, < 1-53 ng/L; Sea-Nine 211, < 1-1.8 ng/L; Irgarol 1051, < 1-4.0 ng/L; dichlofluanid, < 1-343 ng/L; and chlorothalonil, < 1-1 ng/L, and the ranges of these alternative compounds in sediment samples were diuron, 32-488 ng/g dw; Sea-Nine 211, 47-591 ng/g dw; Irgarol, 33-128 ng/g dw; dichlofluanid, 67-8038 ng/g dw; and chlorothalonil, 31-2975 ng/g dw. Thus, the OTs and alternative biocides have still been detected in water and sediment samples from closed sea areas.

Development of Simultaneous Determination Method of Pesticide High Toxic Metabolite 3,4-Dichloroaniline and 3,5 Dichloroaniline in Chives Using HPLC-MS/MS

3,4-dichloroaniline (3,4-DCA) and 3,5-dichloroaniline (3,5-DCA) are, respectively, the primary metabolites deriving from the breakdown of phenylurea herbicides and dicarboximide fungicides in both soils and plants, whose residues in vegetable products have a heightened concern considering their higher health risks to humans and greater toxicity than the parent compounds in the environment. In this study, a sensitive high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was developed for the simultaneous determination of 3,4-DCA and 3,5-DCA residues in chive products based on the optimization of HPLC-MS/MS chromatographic and mass-spectrometric conditions using the standard substances and the modified QuEChERS preparation technique. The preparation efficiency of 3,4-DCA and 3,5-DCA from chive samples showed that acetonitrile was the best extractant. The combination of the purification agent graphite carbon black + primary secondary amine and the eluting agent acetonitrile + toluene (4:1, v/v) had a satisfactory purification effect. The linear correlation coefficients (R2) were more than 0.996 with the six concentration range of 0.001-1.000 mg/L for 3,4-DCA and 3,5-DCA. The limit of detection and limit of quantitation of this method was 0.6 and 2.0 µg/kg for 3,4-DCA, as well as 1.0 and 3.0 µg/kg for 3,5-DCA, respectively. The matrix effect range of 3,4-DCA and 3,5-DCA in chive tissues was from -9.0% to -2.6% and from -4.4% to 2.3%, respectively. The fortified recovery of 3,4-DCA and 3,5-DCA in chive samples at four spiked levels of 0.001-1.000 mg/kg was 75.3-86.0% and 78.2-98.1%, with the relative standard deviation of 2.1-8.5% and 1.4-11.9%, respectively. The limit of detection (LOD) and limit of quantification (LOQ) of the method were 0.6, 2.0, and 1.0, 3.03 for 4-DCA and 3,5-DCA, respectively. This study highlights that the analytical method established here can efficiently and sensitively detect residues of 3,4-DCA and 3,5-DCA residues for monitoring chive products. The method was successfully applied to 60 batches of actual vegetable samples from different regions.

A Stable Fe-Zn Modified Sludge-Derived Biochar for Diuron Removal: Kinetics, Isotherms, Mechanism, and Practical Research

To remove typical herbicide diuron effectively, a novel sludge-derived modified biochar (SDMBC600) was prepared using sludge-derived biochar (SDBC600) as raw material and Fe-Zn as an activator and modifier in this study. The physico-chemical properties of SDMBC600 and the adsorption behavior of diuron on the SDMBC600 were studied systematically. The adsorption mechanisms as well as practical applications of SDMBC600 were also investigated and examined. The results showed that the SDMBC600 was chemically loaded with Fe-Zn and SDMBC600 had a larger specific surface area (204 m²/g) and pore volume (0.0985 cm³/g). The adsorption of diuron on SDMBC600 followed pseudo-second-order kinetics and the Langmuir isotherm model, with a maximum diuron adsorption capacity of 17.7 mg/g. The biochar could maintain a good adsorption performance (8.88-12.9 mg/g) under wide water quality conditions, in the pH of 2-10 and with the presence of humic acid and six typical metallic ions of 0-20 mg/L. The adsorption mechanisms of SDMBC600 for diuron were found to include surface complexation, π-π binding, hydrogen bonding, as well as pore filling. Additionally, the SDMBC600 was tested to be very stable with very low Fe and Zn leaching concentration ≤0.203 mg/L in the wide pH range. In addition, the SDMBC600 could maintain a high adsorption capacity (99.6%) after four times of regeneration and therefore, SDMBC600 could have a promising application for diuron removal in water treatment.

Water quality criteria derivation and tiered ecological risk evaluation of antifouling biocides in marine environment

This study provides a comprehensive compilation of published toxicological and environmental data further used to assess the ecological risks of six antifouling biocides, including tributyltin (TBT), Irgarol 1051, Diuron, Chlorothalonil, 4,5-Dichloro-N-octyl-3(2H)-isothiazolone (DCOIT), and Dichlofluanid. The standard maximum concentration and standard continuous concentration of antifouling biocides were derived by the species susceptibility distribution method. Following that, the ecological risk assessment of antifouling biocides in the aquatic environment was conducted using the hazard quotient, margin of safety, joint probability curve, and Monte Carlo random sampling method. The following is a concise list of the antifouling biocide dangers associated with acute and chronic risks: Irgarol 1051 > TBT > Diuron > DCOIT > Chlorothalonil > Dichlofluanid. It is strongly advised that systematic and ongoing monitoring of these biocides in coastal areas take place, as well as the creation of acceptable and efficient environmental protection measures, to safeguard the coastal environment's services and functions.

Chronic effects of environmental concentrations of antifoulant diuron on two marine fish: Assessment of hormone levels, immunity, and antioxidant defense system

The presence and toxicity of waterborne diuron in aquatic environments pose a severe threat to non-target organisms. However, the chronic impact of diuron in marine fish has been poorly investigated. In this study, we report the chronic effects (30 and 60 days) of environmentally relevant concentrations of diuron (0.1, 1, and 10 μg L^-1) on economically important marine fish, red seabream (Pagrus major), and black rockfish (Sebastes schlegelii) by evaluating several parameters, including hormone levels, immunity, hepatic function, and antioxidant defense. Significant decreases in 17β-estradiol and 11-ketotestosterone levels and gonadosomatic index were observed on day 60 in fish exposed to 10 μg L^-1 diuron. Parameters of immunity, such as alternative complement activity, lysozyme activity, and total immunoglobulin levels, were significantly lowered by 60-day exposure to 10 μg L^-1 diuron in both fish. Significant decreases in the hepatic enzyme activities of alanine transaminase and aspartate transaminase were observed with an induction of cortisol on day 60 in fish exposed to 10 μg L-¹ diuron. Intracellular malondialdehyde and glutathione levels were significantly increased by 10 μg L-¹ diuron at day 60 with an increase in the enzymatic activities of catalase and superoxide dismutase. Overall, black rockfish were more sensitive to diuron than red seabream. These results suggest that consistent exposure to environmentally relevant concentrations of diuron is detrimental to the reproduction, immunity, and health of marine fish.

Atlantic cod (Gadus morhua) embryos are highly sensitive to short-term 3,4-dichloroaniline exposure

3,4-dichloroaniline (3,4-DCA) is one of the most widely produced anilines world-wide, used in plastic packaging, fabrics, pharmaceuticals, pesticides, dyes and paints as well as being a degradation product of several pesticides. 3,4-DCA has been detected in freshwater, brackish and marine environments. Although freshwater toxicity thresholds exist, very little toxicological information is available on marine and cold-water species. In this study, we exposed Atlantic cod (Gadus morhua) embryos (3-7 days post fertilization) to 3,4-DCA concentrations ranging from 8-747 μg/L for 4 days followed by a recovery period in clean sea water until 14 days post fertilization (dpf). The cod embryos were significantly more sensitive to acute 3,4-DCA exposure compared to other species tested and reported in the literature. At the highest concentration (747 μg/L), no embryos survived until hatch, and even at the lowest concentration (8 μg/L), a small, but significant increase in mortality was observed at 14 dpf. Delayed and concentration-dependent effects on surviving yolk-sac larvae, manifested as cardiac, developmental and morphometric alterations, more than a week after exposure suggest potential long-term effects of transient embryonic exposure to low concentrations of 3,4-DCA.

Effects of the herbicide Irgarol 1051 on the transcriptome of hermatypic coral Acropora tenuis and its symbiotic dinoflagellates

Coral reefs face multiple threats, including climate change, agricultural runoff, shipping activities, coastal development, and chemical pollutants. Irgarol 1051, a PSII herbicide, has been used as an antifouling booster since the previously used antibiofouling agent tributyltin (TBT) was banned worldwide. Although the mechanisms through which elevated temperatures cause coral bleaching have been reported, it remains unclear how PSII herbicides cause bleaching. Thus, in this study, we investigated the transcriptomes of Acropora tenuis and its symbiotic dinoflagellates by RNA-sequencing (RNA-Seq) to elucidate the molecular mechanisms underlying Irgarol-induced bleaching. Coral exposure to 10 μg/L Irgarol for 7 d affected coral body colour, specifically by an increase in their red, green, and blue (RGB) values; however, no such effect was observed in corals exposed to 1 μg/L Irgarol. RNA-Seq revealed the differentially expressed genes (DEGs) in corals and symbiotic dinoflagellates following Irgarol exposure. Coral DEGs encoded green fluorescent protein, blue-light-sensing photoreceptor (cryptochrome), chromoprotein, caspase 8, and nuclear receptors; DEGs in symbiotic dinoflagellates encoded light-harvesting proteins, photosystem II proteins, and heat shock proteins (i.e. HSP70 and HSP90), and ubiquitin. Bioinformatic analyses revealed that both Irgarol treatments disrupted various gene ontology terms, pathways, and protein interaction networks; these are different in corals (e.g. oxidative phosphorylation, metabolic pathway, transforming growth factor-β signalling pathway, adherens junction, and apoptosis) and symbiotic dinoflagellates (e.g. protein processing in endoplasmic reticulum, carbon fixation in photosynthetic organisms, metabolic pathway, and photosynthesis). Our data suggest that Irgarol disrupts the expression of various coral genes, thereby affecting various gene ontology terms, pathways, and protein interaction networks. Our study provides new insights into the potential molecular mechanisms underlying the bleaching effect of PSII herbicides, such as Irgarol, on corals and symbiotic dinoflagellates.

Effects of 3,4-dichloroaniline (3,4-DCA) and 4,4'-methylenedianiline (4,4'-MDA) on sex hormone regulation and reproduction of adult zebrafish (Danio rerio)

3,4-dichloroaniline (3,4-DCA) and 4,4'-methylenedianiline (4,4'-MDA) have been widely used in manufacture of many industrial and consumer products, and hence often detected in aquatic environment. Reproductive toxicity of aniline and its derivatives in aquatic organisms has been suggested, however, knowledge on the endocrine disruption potentials and toxicological consequences of both anilines are not well understood, especially in fish. In this study, we aimed to understand the effects of 3,4-DCA and 4,4'-MDA on sex hormone regulation and reproduction of adult zebrafish (Danio rerio). Following 21 d exposure, significant decreases of the reproduction were observed at 0.38 mg/L 3,4-DCA, and 4.6 mg/L 4,4'-MDA. Moreover, plasma concentrations of testosterone (T) and 17β-estradiol (E2) level were significantly decreased in both male and female fish following the exposure. The sex hormone changes could be explained by the regulatory changes of the genes along the hypothalamic-pituitary-gonadal (HPG) axis, including significant down-regulation of steroidogenic acute regulatory protein (star) and cytochrome P450 family 19 subfamily A (cyp19a) genes in the gonad. Moreover, inhibition of gonadotropin hormone signaling and prostaglandin-endoperoxide synthase 2 (ptgs2) gene expression were observed, suggesting potential disruption of oocyte maturation and ovulation by the exposure. Our observations indicate that 3,4-DCA and 4,4'-MDA can impair reproduction of zebrafish potentially through disruption of steroid hormone synthesis and ovulation.

Antifouling biocides as a continuous threat to the aquatic environment: Sources, temporal trends and ecological risk assessment in an impacted region of Brazil

Antifouling biocides, such as irgarol and diuron, are commonly used in antifouling paints. Recently, studies carried out in a Brazilian region of ecological concern have warned for extremely high levels of these biocides. So, this work focused on a 4-year (2015-2018) evaluation considering the occurrence, environmental fate, seasonal variations and ecological risk assessment of irgarol and diuron in water and sediment from São Marcos Bay, Brazil, which is an area of international relevance located in the Amazon region. The results showed the ubiquitous presence of antifouling biocides, as well as their wide distribution along the bay. The concentration range of irgarol was between <0.8 and 89.4 ng L^-1 in water and between <0.5 and 9.2 ng g^-1dw in sediments, whereas diuron showed a range between <1.4 and 22.0 ng L^-1 in water and between <2.0 and 15.0 ng g^-1dw in sediments. The distribution of the biocides was mainly related to the intense Bay hydrodynamics. The environmental risk assessment showed that irgarol and diuron posed "high risk" to the aquatic biota of São Marcos Bay, exceeding international Environmental Quality Guidelines. The results represent a robust study on the environmental fate of such biocides and intend to be a useful data source for eventual legislation since regulation concerning antifouling substances is necessary for Brazil.

Booster Biocides Levels in the Major Blood Cockle (Tegillarca granosa L., 1758) Cultivation Areas along the Coastal Area of Peninsular Malaysia

Booster biocides have been rapidly growing in use, mainly in the shipping industry and in agricultural activities. The use of booster biocides is known to cause adverse effects on marine ecosystems, such as by inhibiting the photosynthesis process in marine plants, and they have the potential to accumulate in marine organisms. In the present study, booster biocides of Irgarol 1051, diuron, 3,4-dichloroaniline (3,4-DCA) and chlorothalonil were measured in the major blood cockle (Tegillarca granosa) cultivation areas along the west coast of Peninsular Malaysia. The highest Irgarol 1051 mean was found in the blood cockle with a value of 98.92 ± 13.65 µg/kg in Kapar, Selangor, while the means of diuron and its metabolites and 3,4-DCA showed the highest values of 40.31 ± 7.61 and 41.42 ± 21.58 µg/kg in Kapar, Selangor and Sungai Ayam, Johor, respectively. Sungai Ayam, Johor also exhibited the highest amount of chlorothalonil of 29.76 ± 8.80 µg/kg. By referring to sediment quality guidelines, about 72% and more than 90% of sediment samples exceeded the environmental risk limits (ERLs) and maximum permissible concentration (MPC) for Irgarol 1051 and diuron, respectively. However, referring to the risk characterization ratio (RCR), none of the blood cockle samples exceeded 1, which means that there is no potential for adverse effects to occur. Thus, the contaminants in the marine ecosystem caused by booster biocides are highlighted as a serious issue, mainly in sediment.

Occurrence and partitioning of antifouling booster biocides in sediments and porewaters from Brazilian Northeast

Fouling organisms attach and grow on submerged surfaces causing several economic losses. Thus, biocides have been introduced in antifouling paints in order to avoid this phenomenon, but their widespread use became a global problem, mainly in ports, leisure and fishing boat harbors, since these substances can be highly toxic to non-target organisms. The occurrence and environmental behavior of antifouling biocides are especially unknown in some peculiar regions, such as Amazon areas. Thus, the aim of this work was to evaluate, for the first time, levels and the partitioning behavior of the antifouling organic biocides irgarol, diuron and also stable degradation products of dichlofluanid and diuron (DMSA and DCPMU, respectively) in sediments and porewaters from a high boat traffic area located in the Northeast of Brazil, a pre-Amazon region. Our results showed high concentrations of irgarol (<1.0-89.7 μg kg^-1) and diuron (<5.0-55.2 μg kg^-1) in sediments. In porewater, DCPMU (<0.03-0.67 μg L^-1) and DMSA (<0.008-0.263 μg L^-1) were the mainly substances detected. High K_d and K_oc obtained for both irgarol and diuron showed a partitioning preference in the solid phase. This work represents one of the few registers of contamination by antifouling substances in Amazonian areas, despite their environmental relevance.

Overlapping and unique toxic effects of three alternative antifouling biocides (Diuron, Irgarol 1051®, Sea-Nine 211®) on non-target marine fish

The use of alternative biocides has increased due to their economic and ecological relevance. Although data regarding the toxicity of commercial alternative biocides in marine organisms are accumulating, little is known about their toxic pathways or mechanisms. To compare the toxic effects of commercial alternative biocides on non-target pelagic fish (flounder) embryos, we investigated the adverse effects of developmental malformation and transcriptional changes. Three biocides including Diuron, Irgarol 1051^® and Sea-Nine 211^® produced a largely overlapping suite of developmental malformations, including tail-fin fold defects and dorsal body axis curvature. In our test, the potencies of these biocides were ranked in the following order with respect to malformation and mortalities: Sea-Nine 211^® > Irgarol 1051^® > Diuron. Consistent with the toxicity rankings, the expression of genes related to heart formation was greater in embryonic flounder exposed to Sea-Nine 211^® than in those exposed to Irgarol 1051^® or Diuron, while expression of genes related to fin malformation was greater in the Irgarol 1051^® exposure group. In analyses of differential gene expression (DEG) profiles (fold change of genes with a cutoff P < 0.05) by high-throughput sequencing (RNA-seq), genes associated with nervous system development, transmembrane transport activity, and muscle cell development were significantly changed commonly. Embryos exposed to Diuron showed changes related to cellular protein localization, whereas genes associated with immune system processes were up-regulated significantly in embryos exposed to Irgarol 1051^®. Genes related to actin filament organization and embryonic morphogenesis were up-regulated in embryos exposed to Sea-Nine 211^®. Overall, our study provides a better understanding of the overlapping and unique developmental toxic effects of three commercial booster biocides through transcriptomic analyses in a non-target species, embryonic flounder.

Endocrine disruption by several aniline derivatives and related mechanisms in a human adrenal H295R cell line and adult male zebrafish

Aniline and aniline derivatives have been widely used in the production of pesticides, pharmaceuticals, cosmetic, dyes, rubber, and adhesives products. These chemicals can easily be released into the environment through industrial and municipal discharges or as degradation byproducts. Several studies have suggested that aniline and some of its derivatives could cause reproductive toxicity in aquatic organisms. However, knowledge on the endocrine disruption potentials of these chemicals is limited only to aniline and associated mechanisms are rarely investigated. The objective of this study was to investigate the potential of major aniline derivatives, i.e., 3,4-dichloroaniline (3,4-DCA), 1-naphthylamine (1-NPA), and 4,4'-methylenedianiline (4,4'-MDA), to disrupt sex steroid production and other biological processes. For this purpose, the human adrenal H295R cell line and adult male zebrafish (Danio rerio) were used. In the H295R cell line, all tested aniline derivatives decreased testosterone (T) levels. Regulatory changes of several steroidogenic genes, i.e., down-regulation of StAR or CYP17 genes, and up-regulation of CYP19A, observed in the H295R cells could explain the sex hormone disruption. In male zebrafish, generally similar directions of changes, i.e., decreases in T levels and increased E2/T ratios, were observed. Again, down-regulation of key steroidogenic genes such as cyp17 or 3β-hsd, but slight up-regulation of cyp19a gene observed in the fish could explain the sex hormone changes. The results of our study demonstrate that all tested aniline derivatives could influence steroidogenesis and disrupt sex hormone balance toward reduced androgenicity. Consequences of anti-androgenicity following long-term exposure warrant further investigation.

Toxicities of the degraded mixture of Irgarol 1051 to marine organisms

Antifoulant Irgarol 1051 (2-methythiol-4-tert-butylamino-6-cyclopropylamino-s-triazine) can be photodegraded into M1 (2-methylthio-4-tert-butylamino-6-amino-s-triazine) and M2 (3-4-tert-butylamino-6-methylthiol-s-triazin-2-ylamino]propion-aldehyde). M3 (2-methylthio-4,6-bis-tert-butylamino-s-triazine) was also detected as a side-product in Irgarol. This study aimed to investigate the combined toxicity of a mixture of these s-triazine compounds to eight marine organisms. A degraded mixture of Irgarol in artificial seawater was obtained by photolysis over 42 d and its composition was quantified by HPLC-UV analyses. Based on short-term toxicity tests on eight selected marine species, the mixture posed significant phytotoxic effects to the cyanobacteria (Chroococcus minor and Synechococcus sp.), the diatoms (Skeletonema costatum and Thalassiosira pseudonana), the macroalgae (Ulva lactuca and Caulerpa peltata) and the dinoflagellate (Prorocentrum dentatum), though the mixture was less toxic to the copepod Tigriopus japonicus. Both Independent Action and Concentration Addition models can generate reasonably satisfactory predictions on the overall mixture toxicity to the two diatoms, implying that the four compounds likely share a similar mode of action and resemble an additive effect in the mixture.

Integrated photocatalytic-biological treatment of triazine-containing pollutants

The degradation of triazine-containing pollutants including simazine, Irgarol^® 1051 and Reactive Brilliant Red K-2G (K-2G) by photocatalytic treatment was investigated. The effects of titanium dioxide (TiO₂) concentration, initial pH of reaction mixture, irradiation time and ultraviolet (UV) intensity on photocatalytic treatment efficiency were examined. Complete decolorization of K-2G was observed at 60 min photodegradation while only 15 min were required to completely degrade simazine and Irgarol^® 1051 under respective optimized conditions. High-performance liquid chromatography (HPLC), gas chromatography/mass spectrometry (GC/MS) and ion chromatography (IC) were employed to identify the photocatalytic degradation intermediates and products. Dealkylated intermediates of simazine, deisopropylatrazine and deethyldeisopropylatrazine, and Irgarol^® 1051 were detected by GC/MS in the initial phase of degradation. Complete mineralization could not be achieved for all triazine-containing pollutants even after prolonged (>72 h) UV irradiation due to the presence of a photocatalysis-resistant end product, cyanuric acid (CA). The toxicities of different compounds before and after photocatalytic treatment were also monitored by three bioassays. To further treat the photocatalysis-resistant end product, a CA-degrading bacterium was isolated from polluted marine sediment and further identified as Klebsiella pneumoniae by comparing the substrate utilization pattern (Biolog™ microplate), fatty acid composition and 16S rRNA gene sequencing. K. pneumoniae efficiently utilized CA from 1 to 2000 mg/L as a good nitrogen source and complete mineralization of CA was observed within 24 h of incubation. This study demonstrates that the biodegradability of triazine-containing pollutants was significantly improved by the photocatalytic pre-treatment, and this proposed photocatalytic-biological integrated system can effectively treat various classes of triazine-containing pollutants.

Identification and characterization of heat shock protein 90 (HSP90) in the hard coral Acropora tenuis in response to Irgarol 1051

To elucidate the effects of the herbicide Irgarol 1051 on the gene expression of heat shock protein 90 (HSP90) in hard corals, we isolated a full-length cDNA encoding HSP90 from Acropora tenuis, which has a deduced open reading frame of 732-amino acid residues with a predicted molecular mass of 84.5 kDa. The amino acid sequence of A. tenuis HSP90 showed a high degree of similarity with the hermatypic-coral HSP90 families. After a 7-d exposure to 1 or 10 μg/L of Irgarol, the body colours of corals in the 10 μg/L treatment group were significantly whiter (bleached), whereas no such effects were observed in the corals in the 1 μg/L treatment group. However, the expression level of coral HSP90 was significantly downregulated after exposure to both 1 and 10 μg/L Irgarol. These results suggest that A. tenuis HSP90 may be a useful molecular biomarker to predict bleaching caused by herbicides.

From TBT to booster biocides: Levels and impacts of antifouling along coastal areas of Panama

Antifouling biocides in surface sediments and gastropod tissues were assessed for the first time along coastal areas of Panama under the influence of maritime activities, including one of the world's busiest shipping zones: the Panama Canal. Imposex incidence was also evaluated in five muricid species distributed along six coastal areas of Panama. This TBT-related biological alteration was detected in three species, including the first report in Purpura panama. Levels of organotins (TBT, DBT, and MBT) in gastropod tissues and surficial sediments ranged from <5 to 104 ng Sn g^-1 and <1-149 ng Sn g^-1, respectively. In addition, fresh TBT inputs were observed in areas considered as moderate to highly contaminated mainly by inputs from fishing and leisure boats. Regarding booster biocides, TCMTB and dichlofluanid were not detected in any sample, while irgarol 1051, diuron and DCOIT levels ranged from <0.08 to 2.8 ng g^-1, <0.75-14.1 ng g^-1, and <0.38-81.6 ng g^-1, respectively. The highest level of TBT (149 ng Sn g^-1) and irgarol 1051 (2.8 ng g^-1), as well as relevant level of DCOIT (5.7 ng g^-1), were detected in a marina used by recreational boats. Additionally, relatively high diuron values (14.1 ng g^-1) were also detected in the Panama Canal associate to a commercial port. DCOIT concentrations were associated with the presence of antifouling paint particles in sediments obtained nearby shipyard or boat maintenance sites. The highest levels of TBT, irgarol 1051, and diuron exceeded international sediment quality guidelines indicating that toxic effects could be expected in coastal areas of Panama. Thus, the simultaneous impacts produced by new and old generations of antifouling paints highlight a serious environmental issue in Panamanian coastal areas.

Antifouling booster biocide extraction from marine sediments: a fast and simple method based on vortex-assisted matrix solid-phase extraction

This paper reports the development of an analytical method employing vortex-assisted matrix solid-phase dispersion (MSPD) for the extraction of diuron, Irgarol 1051, TCMTB (2-thiocyanomethylthiobenzothiazole), DCOIT (4,5-dichloro-2-n-octyl-3-(2H)-isothiazolin-3-one), and dichlofluanid from sediment samples. Separation and determination were performed by liquid chromatography tandem-mass spectrometry. Important MSPD parameters, such as sample mass, mass of C18, and type and volume of extraction solvent, were investigated by response surface methodology. Quantitative recoveries were obtained with 2.0 g of sediment sample, 0.25 g of C18 as the solid support, and 10 mL of methanol as the extraction solvent. The MSPD method was suitable for the extraction and determination of antifouling biocides in sediment samples, with recoveries between 61 and 103% and a relative standard deviation lower than 19%. Limits of quantification between 0.5 and 5 ng g^-1 were obtained. Vortex-assisted MPSD was shown to be fast and easy to use, with the advantages of low cost and reduced solvent consumption compared to the commonly employed techniques for the extraction of booster biocides from sediment samples. Finally, the developed method was applied to real samples. Results revealed that the developed extraction method is effective and simple, thus allowing the determination of biocides in sediment samples.

Sorption potential of different biomass fly ashes for the removal of diuron and 3,4-dichloroaniline from water

Hazardous contaminants in water and biomass fly ash spillage are causes for environmental and health concern. We selected five fly ashes generated from olive-mill (O,P, G and H) and greenhouse vegetable (I) waste used as biomass fuel in order to quantify their capacity to remove diuron and 3,4-dichloroaniline (DCA) from water. To understand the sorption processes involved, four kinetic models and two adsorption isotherms were assayed. The pseudo second-order kinetic showed the best fit (R²>0.99). The initial adsorption rate constant was found to be faster for DCA than for diuron. The Freundlich adsorption constants of ashes O, P, G and H for diuron were more than 2-fold higher than for DCA (Kf=109-16μg^1-1/ng^-1mL^-1). The alkaline pH of these fly ashes plays an important role in the adsorption process. Sorption/desorption processes were significantly affected by iron oxide content. DCA sorption was also influenced by particle size and carbon content. Low hysteresis coefficient values (H=0.01-0.26) revealed an irreversible sorption process. The study presents novel information on the immobilization of hazardous chemicals in water by biomass fly ashes generated from olive-oil industry and greenhouse crop waste.

Spatial distribution and composition of aliphatic hydrocarbons, polycyclic aromatic hydrocarbons and hopanes in superficial sediments of the coral reefs of the Persian Gulf, Iran

This study is the first quantitative report on petroleum biomarkers from the coral reefs systems of the Persian Gulf. 120 reef surface sediment samples from ten fragile coral reef ecosystems were collected and analyzed for grain size, biogenic elements, elemental ratios, and petroleum biomarkers (n-alkanes, PAHs¹ and Hopanes) to assess the sources and early diagenesis of sedimentary organic matter. The mean grain size of the reef sediments ranged from 13.56 to 37.11% (Clay), 26.92 to 51.73% (Sand) and 35.97 to 43.85% (Silt). TOC² (3.35-9.72 mg.g^-1) and TON³ (0.4-1.10 mg.g^-1) were identified as influencing factors on the accumulation of petroleum hydrocarbons, whilst BC⁴ (1.08-3.28 mg.g^-1) and TIN⁵ (0.13-0.86) did not exhibit any determining effect. Although BC and TIN demonstrated heterogeneous spatial distribution, TOC and TON indicated homogenous distribution with continually upward trend in concentration from the east to west ward of the Gulf. The mean calculated TOC/TN ratios vacillated according to the stations (p < 0.05) from 2.96 at Shidvar Island to 8.64 at Hengam Island. The high TOC/TN ratios were observed in the Hengam (8.64), Kharg (8.04) and Siri (6.29), respectively, suggesting a predominant marine origin. The mean concentrations of ∑C_11-35n-alkanes, ∑30 PAHs and ∑9Hopanes were found in the ranges of 385-937 μg.g^-1dw, (overall mean:590 μg.g^-1dw), 326-793 ng.g^-1dw (499 ng.g^-1dw), 88 to 568 ng.g^-1 d (258 ng.g^-1dw), respectively. Higher concentrations of detected petroleum biomarkers in reef sediments were chiefly distributed near main industrial areas, Kharg, Lavan and Siri, whilst the lower concentrations were in Hormoz and Qeshm. In addition, one-way ANOVA⁶ analysis demonstrated considerably significant differences (p < 0.05) among concentration of detected total petroleum hydrocarbons between most sampling locations. Some sampling sites especially Kharg, Lavan, Siri and Lark indicated higher concentration of n-alkanes due to the higher maintenance of organic matter by high clay content in the sediments. Furthermore, most sediment samples, except for Hormoz, Qeshm and Hengam showed an even carbon preference for n-alkanes which could be correlated to bacterial input. NPMDS⁷ analysis also demonstrated that among the congeners of petroleum biomarkers, n-C₁₂,n-C₁₄, n-C₁₆,n-C₁₈ and n-C₂₀ for n-alkanes, Phe⁸ and Naph⁹ along with their Alkyl homologues for PAHs (2-3 rings accounted for 60%) and C₃₀αβ and C₂₉αβ for Hopanes were discriminated from their other congeners in the whole study area. Our results based on the PCA¹⁰ analysis and diagnostic indices of AHs¹¹ and PAHs along with ring classification of PAHs, in addition, the ubiquitous presence of UCM,¹² and Hopanes revealed that the main sources of the pollution were petroleum and petroleum combustion mainly from offshore oil exploration and extraction, discharge of pollutants from shipping activities.

Antifouling booster biocides in coastal waters of Panama: First appraisal in one of the busiest shipping zones

A baseline study for antifouling booster biocides in coastal waters of Panama is presented. Solid Phase Extraction (SPE) was used for extraction and Liquid Chromatography tandem Mass Spectrometry (LC-MS/MS) was applied for the quantification of irgarol 1051, diuron, (2-thiocyanomethylthio)benzothiazole (TCMTB), 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one (DCOIT) and dichlofluanid. TCMTB, DCOIT and dichlofluanid were not detected in any seawater sample, while irgarol 1051 and diuron were found in four out of thirteen areas (<0.3 to 5.0ngL^-1 and <2.7 to 70ngL^-1, respectively). Although the hotspots were identified in areas influenced by marinas and in one of the ports, diuron and irgarol 1051 levels were all lower than the threshold levels set by the Environmental Quality Standard of United Kingdom. However, this is only a snapshot of the status of costal water contamination by antifouling booster biocides and a more comprehensive assessment is needed to assess risks associated to long term exposure.

Effects of antifouling booster biocide Irgarol 1051 on the structure of free living nematodes: a laboratory experiment

A mesocosm experiment was conducted to evaluate the effects of Irgarol on nematode diversity, composition and trophic structure. Sediment samples were experimentally contaminated using four increasing Irgarol concentrations [I1 (11.5 ng g(-1)), I2 (35 ng g(-1)), I3 (105 ng g(-1)) and I4 (315 ng g(-1))] and compared to non-contaminated sediments (controls). Nematode diversity as the number of nematodes species (S) and species richness (d) was significantly lower in all Irgarol treatments than in the controls while the evenness (J') increased significantly in I4 treated mesocosms. The nematode species composition significantly changed following Irgarol concentrations. Paracomesoma dubiun and Terschellingia longicaudata appeared as "tolerant" species to the highest Irgarol concentration. Additionally, Chromadorina germanica and Microlaimus cyatholaimoides appeared as "opportunistic" species. In contrast, Daptonema normandicum seemed to be a "sensitive" species to Irgarol contamination. Irgarol modified also the nematode trophic structure where the relative abundance of deposit feeders decreased significantly in all the treatments compared to control mesocosms and optional predators decreased only in treated mesocosms with I3. Epigrowth feeders increased significantly in treated mesocosms with I3 and I4 and the microvores increased with I1 and decreased with I4. The relative abundance of ciliate consumers appeared unaffected by the presence of Irgarol contamination. Our results open new perspectives on the potential impact of antifouling booster biocide Irgarol 1051 on nematode biodiversity and functional diversity as trophic structures.