Occurrence and environmental implications of pharmaceuticals in Chinese municipal sewage sludge

The presence of pharmaceuticals in aquatic environment has become a topic of concern because of their potential adverse effects on human health and wildlife species. A total of 45 dewatered sewage sludge samples were collected throughout China and analyzed for 30 commonly consumed pharmaceutical residues. Ofloxacin was found to be the dominant contaminant with concentrations up to 24 760 μg kg⁻¹, followed by oxytetracycline (5280 μg kg⁻¹), norfloxacin (5280 μg kg⁻¹) and ketoprofen (4458 μg kg⁻¹). The concentration of pharmaceutical residues varied greatly depending on the operation conditions of wastewater treatment plants and sampling locations. Poor agreement was found between the predicted (calculation based on the annual consumption and coefficient of sludge water partition) and detected concentrations of the pharmaceuticals indicating that the occurrence of pharmaceutical residues was affected by various factors such as loading rates, sewage properties and the chemical properties such as the contribution from polar groups. National wide fate and ecotoxicity study is required for the development of control strategies.     

PBDE flame retardants and PCBs in migrating Steller sea lions (Eumetopias jubatus) in the Strait of Georgia, British Columbia, Canada

Polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) were measured in blubber biopsy samples from 22 live-captured Steller sea lions (Eumetopias jubatus) that had just entered the Strait of Georgia, British Columbia, Canada, for their overwintering feeding season. ∑PBDE ranged from 50 μg kg⁻¹ (lipid weight) in adult females to 3780 μg kg⁻¹ in subadult individuals. ∑PCBs ranged from 272 μg kg⁻¹ in adult females to 14 280 μg kg⁻¹ in subadult individuals. While most PBDE and PCB congeners were transferred through milk to pups, PCBs with log K_OW > 7.0 (PCBs 206, 207, 208 and 209) appeared constrained, resulting in a lighter mixture in pups compared to adult females. The ratio of individual PCB congeners by metabolic group (Groups I, II, III, IV and V) to PCB-153 regressed against length of males suggested poor biotransformation of these compounds (slopes did not differ from zero, p > 0.05). PBDE congeners 49, 99, 153 and 183 appeared bioaccumulative (slopes of ratio BDE/PCB 153 versus length were higher than zero, p < 0.05), but the dominance of the single congener, BDE-47 (64% of total PBDEs), likely due in part to debromination pathways, reduced our ability to explore congener-specific dynamics of PBDEs in these pinnipeds. With 80% of our Steller sea lions exceeding a recent toxicity reference value for PCBs, the fasting-associated mobilization of these contaminants raises concerns about a heightened vulnerability to adverse effects during annual migrations.     

Residues and dynamics of pymetrozine in rice field ecosystem

The fate of pymetrozine was studied in rice field ecosystem, and a simple and reliable analytical method for determination of pymetrozine in soil, rice straw, paddy water and brown rice was developed. Pymetrozine residues were extracted from samples, cleaned up by solid phase extraction (SPE) and then determined by high-performance liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESI-MS-MS). The average recovery was 81.2-88.1% from soil, 83.4-88.6% from rice straw, 87.3-94.1% from paddy water and 82.9-85.3% from brown rice. The relative standard deviation (RSD) was less than 15%. The limits of detection (LODs) of pymetrozine calculated as a sample concentration were 0.0003 mg kg⁻¹ (mg L⁻¹) for soil and paddy water, 0.001 mg kg⁻¹ for brown rice and rice straw. The results of kinetics study of pymetrozine residue showed that pymetrozine degradation in water, soil, and rice straw coincided with C = 0.194e^−0.986t, C = 0.044e^−0.099t, and C = 0.988e^−0.780t, respectively; the half-lives were about 0.70 d, 7.0 d and 0.89 d, respectively. The degradation rate of pymetrozine in water was the fastest, followed by rice straw. The highest final pymetrozine residues in brown rice were 0.01 mg kg⁻¹, which was lower than the EU’s upper limit of 0.02 mg kg⁻¹ in rice. Therefore, a dosage of 300-600 g a.i.hm⁻² was recommended, which could be considered as safe to human beings and animals.     

Assessment of fates of estrogens in wastewater and sludge from various types of wastewater treatment plants

We measured five estrogens in the wastewater samples from the municipal wastewater treatment plants (M-WWTPs), livestock wastewater treatment plants (L-WWTPs), hospital WWTPs (H-WWTPs) and pharmaceutical manufacture WWTPs (P-WWTPs) in Korea. The L-WWTPs showed the highest total concentration (0.195-10.4 μg L⁻¹) of estrogens in the influents, followed by the M-WWTPs (0.028-1.15 μg L⁻¹), H-WWTPs (0.068-0.130 μg L⁻¹) and P-WWTPs (0.015-0.070 μg L⁻¹). Like the influents, the L-WWTPs (0.003-0.729 μg L⁻¹) and the M-WWTPs (0.001-0.299 μg L⁻¹) also showed higher total concentration of estrogens in the effluents than the H-WWTPs (0.002-0.021 μg L⁻¹) and P-WWTPs (0.011 μg L⁻¹ in one sample). The L-WWTPs (37.5-543 μg kg⁻¹, dry weight) showed higher total concentrations in sludge than the M-WWTPs (3.16-444 μg kg⁻¹, dry weight) like the wastewater. The distribution of estrogens in the WWTPs may be affected by their metabolism in the human body, their transition through biological treatment processes, and their usage for livestock growth. Unlike the concentration results, the daily loads of estrogens from the M-WWTPs were the highest, which is related to the high capacities of WWTPs.     

Aerobic degradation of tetrabromobisphenol-A by microbes in river sediment

This study investigated the aerobic degradation of tetrabromobisphenol-A (TBBPA) and changes in the microbial community in river sediment from southern Taiwan. Aerobic degradation rate constants (k₁) and half-lives (t_1/2) for TBBPA (50 μg g⁻¹) ranged from 0.053 to 0.077 d⁻¹ and 9.0 to 13.1 d, respectively. The degradation of TBBPA (50 μg g⁻¹) was enhanced by adding yeast extract (5 mg L⁻¹), sodium chloride (10 ppt), cellulose (0.96 mg L⁻¹), humic acid (0.5 g L⁻¹), brij 30 (55 μM), brij 35 (91 μM), rhamnolipid (130 mg L⁻¹), or surfactin (43 mg L⁻¹), with rhamnolipid yielding a higher TBBPA degradation than the other additives. For different toxic chemicals in the sediment, the results showed the high-to-low order of degradation rates were bisphenol-A (BPA) (50 μg g⁻¹) > nonylphenol (NP) (50 μg g⁻¹) > 4,4′-dibrominated diphenyl ether (BDE-15) (50 μg g⁻¹) > TBBPA (50 μg g⁻¹) > 2,2′,3,3′,4,4′,5,5′,6,6′-decabromodiphenyl ether (BDE-209) (50 μg g⁻¹). The addition of various treatments changed the microbial community in river sediments. The results also showed that Bacillus pumilus and Rhodococcus ruber were the dominant bacteria in the process of TBBPA degradation in the river sediments.     

Carry-over of dietary organochlorine pesticides, PCDD/Fs, PCBs, and brominated flame retardants to Atlantic salmon (Salmo salar L.) fillets

Information on carry-over of contaminants from feed to animal food products is essential for appropriate human risk assessment of feed contaminants. The carry-over of potentially hazardous persistent organic pollutants (POPs) from feed to fillet was assessed in consumption sized Atlantic salmon (Salmo salar). Relative carry-over (defined as the fraction of a certain dietary POP retained in the fillet) was assessed in a controlled feeding trial, which provided fillet retention of dietary organochlorine pesticides (OCPs), dioxins (PCDD/Fs), polychlorinated biphenyls (PCBs), and brominated flame retardants (BFRs). Highest retention was found for OCPs, BFRs and PCBs (31-58%), and the lowest retentions were observed for PCDD/Fs congeners (10-34%). National monitoring data on commercial fish feed and farmed Atlantic salmon on the Norwegian market were used to provide commercially relevant feed-to-fillet transfer factors (calculated as fillet POP level divided by feed POP level), which ranged from 0.4 to 0.5, which is a factor 5-10 times higher than reported for terrestrial meat products. For the OCP with one of the highest relative carry-over, toxaphene, uptake and elimination kinetics were established. Model simulations that are based on the uptake and elimination kinetics gave predicted levels that were in agreement with the measured values. Application of the model to the current EU upper limit for toxaphene in feed (50 μg kg⁻¹) gave maximum fillet levels of 22 μg kg⁻¹, which exceeds the estimated permissible level (21 μg kg⁻¹) for toxaphene in fish food samples in Norway.     

Organochlorine pesticide residues in sediments from the Uganda side of Lake Victoria

Organochlorine (OC) residues were analysed in 117 sediment samples collected from four bays of the Uganda side of Lake Victoria. The sediments were collected with a corer at a depth of 0-20 cm, and extracted for OC residues using a solid dispersion method. The extracts were cleaned using gel permeation chromatography and analysed for pesticide residues using a gas chromatograph (GC) equipped with an electron capture detector. The results were confirmed using a GC equipped with a mass spectrometer (MS). A total of 16 OC residues, most of them persistent organic pollutants (POPs) were identified and quantified. The OC residue levels were expressed on an oven dry weight (d.w.) basis. Endosulphan sulphate, in the range of 0.82-5.62 μg kg⁻¹d.w., was the most frequently detected residue. Aldrin and dieldrin were in the ranges of 0.22-15.96 and 0.94-7.18 μg kg⁻¹d.w., respectively. DDT and its metabolites lay between 0.11-3.59 for p,p′-DDE, 0.38-4.02 for p,p′-DDD, 0.04-1.46 for p,p′-DDT, 0.07-2.72 for o,p′-DDE and 0.01-1.63 μg kg⁻¹d.w. for o,p′-DDT. The levels of γ-HCH varied from 0.05 to 5.48 μg kg⁻¹d.w. Heptachlor was detected only once at a level of 0.81 μg kg⁻¹d.w., while its photo-oxidation product, heptachlor epoxide, ranged between non-detectable (ND) to 3.19 μg kg⁻¹d.w. Chlordane ranged from ND to 0.76 μg kg⁻¹d.w. Based on the threshold effect concentration (TEC) for fresh water ecosystems, aldrin and dieldrin were the only OCs that seemed to be a threat to the lake environment.     

Polycyclic aromatic hydrocarbons: bees, honey and pollen as sentinels for environmental chemical contaminants

Three beehive matrices, sampled in six different apiaries from West France, were analyzed for the presence of four polycyclic aromatic hydrocarbons (PAH4: benzo[a]pyrene, benzo[a]anthracene, benzo[b]fluoranthene and chrysene). Samples were collected during four different periods in both 2008 and 2009. Honey samples showed the lowest levels of PAH4 contamination (min = 0.03 μg kg⁻¹; max = 5.80 μg kg⁻¹; mean = 0.82 μg kg⁻¹; Sd = 1.17). Bee samples exhibited higher levels of PAH4 contamination (min = 0.32 μg kg⁻¹; max = 73.83 μg kg⁻¹; mean = 7.03 μg kg⁻¹; Sd = 17.83) with a great dispersion of the concentrations due to four main events of high concentrations. Pollen samples showed only one major episode with the highest PAH4 concentration found (min = 0.33 μg kg⁻¹; max = 129.41 μg kg⁻¹; mean = 7.10 μg kg⁻¹; Sd = 22.28). The PAH4 concentrations found were significantly influenced by the landscape context for all beehive samples.     

Assessment of persistent organic pollutants in sediments from Lower Mekong River Basin

Organochlorine compounds (OCs) in sediments collected from various locations in Lower Mekong River Basin (MRB) in Laos and Thailand were examined to elucidate their occurrence, distribution and potential ecological risk. Concentration of PCBs and DDTs were higher than other OCs, ranging from 0.18 to 310 μg kg⁻¹ dry wt. and from 0.027 to 52 μg kg⁻¹ dry wt., respectively, whereas CHLs, HCHs and HCB were 1-3 orders of magnitude lower. Geographical distribution indicates that levels of PCBs, DDTs and CHLs in the Vientiane canal were significantly higher than those in mainstream of Mekong River, Phong River and its surrounding areas, indicating significant sources of these compounds in urbanized areas. Comparison with other parts of MRB indicates that PCBs were higher in Laos, whereas DDTs were more prevalent in Mekong Delta, indicating location specific contaminations of these compounds in MRB. The ratios of DDTs composition indicate possible difference in the historical input of DDT among locations in and around Mekong River. Hazard assessment of PCBs and DDTs indicate possible toxic potential particularly in areas close to point sources such as intensive human activities and agricultural areas which highlight the need for further study.     

A human health risk assessment of rare earth elements in soil and vegetables from a mining area in Fujian Province,Southeast China

Contaminated food through dietary intake has become the main potential risk impacts on human health. This study investigated concentrations of rare earth elements (REEs) in soil, vegetables, human hair and blood, and assessed human health risk through vegetables consumption in the vicinity of a large-scale mining area located in Hetian Town of Changting County, Fujian Province, Southeast China. The results of the study included the following mean concentrations for total and bio-available REEs of 242.92 ± 68.98 (135.85–327.56) μg g⁻¹ and 118.59 ± 38.49 (57.89–158.96) μg g⁻¹ dry weight (dw) in agricultural soil, respectively, and total REEs of 3.58 ± 5.28 (0.07–64.42) μg g⁻¹ dw in vegetable samples. Concentrations of total REEs in blood and hair collected from the local residents ranged from 424.76 to 1274.80 μg L⁻¹ with an average of 689.74 ± 254.25 μg L⁻¹ and from 0.06 to 1.59 μg g⁻¹ with an average of 0.48 ± 0.59 μg g⁻¹ of the study, respectively. In addition, a significant correlation was observed between REEs in blood and corresponding soil samples (R² = 0.6556, p < 0.05), however there was no correlation between REEs in hair and corresponding soils (p > 0.05). Mean concentrations of REEs of 2.85 (0.59–10.24) μg L⁻¹ in well water from the local households was 53-fold than that in the drinking water of Fuzhou city (0.054 μg L⁻¹). The health risk assessment indicated that vegetable consumption would not result in exceeding the safe values of estimate daily intake (EDI) REEs (100−110 μg kg⁻¹ d⁻¹) for adults and children, but attention should be paid to monitoring human beings health in such rare earth mining areas due to long-term exposure to high dose REEs from food consumptions.     

Occurrence of antibiotics in water, sediments, aquatic plants, and animals from Baiyangdian Lake in North China

This study investigated the presence and distribution of 22 antibiotics, including eight quinolones, nine sulfonamides and five macrolides, in the water, sediments, and biota samples from Baiyangdian Lake, China. A total of 132 samples were collected in 2008 and 2010, and laboratory analyses revealed that antibiotics were widely distributed in the lake. Sulfonamides were the dominant antibiotics in the water (0.86-1563 ng L⁻¹), while quinolones were prominent in sediments (65.5-1166 μg kg⁻¹) and aquatic plants (8.37-6532 μg kg⁻¹). Quinolones (17.8-167 μg kg⁻¹) and macrolides [from below detection limit (BDL) to 182 μg kg⁻¹] were often found in aquatic animals and birds. Salvinia natans exhibited the highest bioaccumulation capability for quinolones among three species of aquatic plants. Geographical differences of antibiotic concentrations were greatly due to anthropogenic activities. Sewage discharged from Baoding City was likely the main source of antibiotics in the lake. Risk assessment of antibiotics on aquatic organisms suggested that algae and aquatic plants might be at risk in surface water, while animals were likely not at risk.     

Formation of dioxins during exposure of pesticide formulations to sunlight

Chlorinated pesticides can contain impurities of dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), and their precursors, as a result of various manufacturing processes and conditions. As precursor formation of PCDD/Fs can also be mediated by ultraviolet light (UV), this study investigated whether PCDD/Fs are formed when currently used pesticides are exposed to natural sunlight. Formulations containing pentachloronitrobenzene (PCNB; n = 2) and 2,4-dichlorophenoxyacetic acid (2,4-D; n = 1) were exposed to sunlight in quartz tubes, and the concentration of 93 PCDD/F congeners were monitored over time. Considerable formation of PCDD/Fs was observed in both PCNB formulations (by up to 5600%, to a maximum concentration of 57 000 μg ∑PCDD/F kg⁻¹) as well as the 2,4-D formulation (by 3000%, to 140 μg ∑PCDD/F kg⁻¹). TEQ also increased by up to 980%, to a maximum concentration of 28 μg kg⁻¹ in PCNB, but did not change in the 2,4-D formulation. Assuming similar yields as observed in the present study as a worst case scenario the use of PCNB in Australia may result in the formation of 155 g TEQ annum⁻¹, contributed primarily by OCDD formation. This warrants detailed evaluations on the contemporary release of PCDD/Fs to the environment after the use of pesticides. Changes in congener profiles (including the ratio of PCDDs to PCDFs (DF ratio)) suggest that pesticide sources of PCDD/Fs after sunlight exposure may not be recognized based on matching source fingerprints established from manufacturing impurities. These changes also provide preliminary insights into the possible formation routes and types of precursors involved.     

The association between total urinary arsenic concentration and renal dysfunction in a community-based population from central Taiwan

Arsenic (As) is an important environmental toxicant that can cause cancer and cardiovascular disease, but the relationship between As exposure and renal dysfunction is not clear. The aim of this study is to examine the association between As exposure and renal dysfunction in a community-based population in central Taiwan. One thousand and forty-three subjects were recruited between 2002 and 2005. The risk for type 2 diabetes was increased by 2-fold (p < 0.05) in subjects with total urinary As (U-As) > 75 μg g⁻¹ creatinine as compared with subjects whose U-As was ?35 μg g⁻¹ creatinine after the adjustment for potential confounders. The adjusted odds ratio for an abnormal β2 microglobulin (B2MG > 0.154 mg L⁻¹) was significantly higher in subjects with U-As > 35 μg g⁻¹ creatinine as compared with the reference group adjusted for age, sex, living area, cigarette smoking, diabetes, and hypertension. The risk for abnormal B2MG and estimated glomerular filtration rate (eGFR < 90 mL min⁻¹ (1.73 m²)⁻¹) was both increased around 2-fold (p < 0.05) in subjects with U-As > 75 μg g⁻¹ creatinine as compared with those with U-As ? 35 μg g⁻¹ creatinine adjusted for all the risk factors plus lead (Pb), cadmium and nickel. The prevalence of abnormal B2MG was 4.82 times higher in subjects with both over the median levels of U-As (85.1 μg L⁻¹) and urinary Pb (18.9 μg L⁻¹) as compared to both lower than the median (p < 0.001). These results indicate that U-As might relate to renal dysfunction even other important risk factors were taken into account. Follow-up studies for causal inference are warranted.     

The influence of mariculture on mercury distribution in sediments and fish around Hong Kong and adjacent mainland China waters

To study the influence of mariculture on mercury (Hg) speciation and distribution in sediments and cultured fish around Hong Kong and adjacent mainland China waters, sediment samples were collected from six mariculture sites and the corresponding reference sites, 200-300 m away from the mariculture sites. Mariculture activities increased total mercury, organic matter, carbon, nitrogen and sulfur concentrations in the surface sediments underneath mariculture sites, possibly due to the accumulation of unconsumed fish feed and fish excretion. However, methylmercury (MeHg) concentrations and the ratio of MeHg to THg (% MeHg) in sediments underneath mariculture sites were lower than the corresponding reference sites. The % MeHg in sediments was negatively correlated (r = −0.579, p < 0.05) with organic matter (OM) content among all sites, indicating that OM may have inhibited Hg methylation in surface sediments. Three mariculture fish species were collected from each mariculture site, including red snapper (Lutjanus campechanus), orange-spotted grouper (Epinephelus coioides) and snubnose pompano (Trachinotus blochii). The average MeHg concentration in fish muscle was 75 μg kg⁻¹ (wet weight), and the dietary intake of MeHg through fish consumption for Hong Kong residents was 0.37 μg kg⁻¹ week⁻¹, which was lower than the corresponding WHO limits (500 μg kg⁻¹ and 1.6 μg kg⁻¹ week⁻¹).     

Identification of two new cytochrome P450 genes and RNA interference to evaluate their roles in detoxification of commonly used insecticides in Locusta migratoria

Composite samples of Australian farmed Yellowtail Kingfish (Seriola lalandi) (YTKF) (n = 27), Mulloway (Argyrosomus hololepidotus) (n = 6) and manufactured feed (n = 5) were analysed to benchmark levels of a broad range of residues and contaminants of potential public health and trade significance. A subset of these samples [YTKF (n = 5), Mulloway (n = 2) and feed (n = 5)] was analysed for dioxins and polychlorinated biphenyls (PCBs). The mean concentration of dioxins in YTKF was 0.6 pg TEQ g⁻¹ (range 0.22-0.8) and in Mulloway was 0.16 pg TEQ g⁻¹ (range 0.16-0.16). The mean concentration of dioxins and dioxin-like PCBs in YTKF was 2.6 pg TEQ g⁻¹ (range 1.4-3.5), while Mulloway had a mean concentration of 0.67 pg TEQ g⁻¹ (range 0.57-0.76). The mean concentration of PCBs in YTKF was 21 μg kg⁻¹ (range 8.6-29) and in Mulloway was 5.4 μg kg⁻¹ (mean 4.7-6). The mean concentration of dioxin-like PCBs in YTKF was 2.1 pg TEQ g⁻¹ (range 1.2-2.8) and in Mulloway was 0.51 pg TEQ g⁻¹ (range 0.41-0.61). The mean mercury concentration in YTKF was 0.03 mg kg⁻¹ (range 0.02-0.05) and in Mulloway it was 0.02 mg kg⁻¹ (range 0.02-0.04). There were no detectable levels of any pesticide or antimicrobial compounds in any sample of YTKF or Mulloway. Attention is drawn to technical differences in port of entry testing programs such as sampling strategies, portion tested, laboratory methodology, residue definitions and reporting conventions that exporters’ products may be subject to. All residues and contaminants were either undetectable or present at very low levels when judged against Australian, Japanese and European Union regulatory standards (where set).     

Production and sedimentation of peptide toxins nodularin-R and microcystin-LR in the northern Baltic Sea

This seven-year survey was primarily targeted to quantification of production of nodularin-R (NOD-R), a cyclic pentapeptide hepatotoxin, in Baltic Sea cyanobacteria waterblooms. Additionally, NOD-R and microcystin-LR (MC-LR; a cyclic heptapeptide toxin) sedimentation rates and NOD-R sediment storage were estimated. NOD-R production (70-2450 μg m⁻³; ∼1 kg km⁻² per season) and sedimentation rates (particles; 0.03-5.7 μg m⁻² d⁻¹; ∼0.3 kg km⁻² per season) were highly variable over space and time. Cell numbers of Nodularia spumigena did not correlate with NOD-R quantities. Dissolved NOD-R comprised 57-100% of total NOD-R in the predominantly senescent, low-intensity phytoplankton blooms and seston. Unprecedentedly intensive MC-LR sedimentation (0.56 μg m⁻² d⁻¹) occurred in 2004. Hepatotoxin sedimentation rates highly exceeded those of anthropogenic xenobiotics. NOD-R storage in surficial sediments was 0.4-20 μg kg⁻¹ (∼0.1 kg km⁻²). Loss of NOD-R within the chain consisting of phytoplankton, seston and soft sediments seemed very effective.     

Risk ranking of multiple-POPs in detritivorous fish from the Río de la Plata

To evaluate the bioaccumulation and the risk associated to consumption of lipid-rich detritivorous fish, a comprehensive set of organic pollutants (n = 213) including polychlorinated biphenyls (PCBs), dioxin like PCBs (dlPCBs), chlorinated pesticides (CHLPs), chlorobenzenes (CBzs), polybrominated diphenyl ethers (PBDEs), polychlorinated dibenzo dioxins and furans (PCDD/F), resolved (ALI) and unresolved aliphatic hydrocarbons (UCM) and linear alkyl benzenes (LABs) were analyzed in Sábalo fish (Prochilodus lineatus) collected in the polluted Metropolitan Buenos Aires coast and in migrating specimens. Fatty fish muscles (lipids: 74 ± 9.3% dry weight) contained homogeneous (24-51% variability) and very high-concentrations of organic pollutants ranging from 60 to 1300 μg g⁻¹ fresh weight (fw) ALI + UCM; 10-40 μg g⁻¹ fw LABs and PCBs; 0.1-1 μg g⁻¹ fw dlPCBs, DDTs, chlordanes, CBzs and PBDEs; 0.01-0.1 μg g⁻¹ fw mirex, endosulfans, aldrin, dieldrin, endrin and 0.07-0.2 ng g⁻¹ PCDD/F. Total toxicity equivalents (TEQs) ranged from 60 to 395 pg g⁻¹ fw (34 ± 17 and 213 ± 124 pg g⁻¹ TEQs for PCDD/F and dlPCBs respectively). These are among the highest concentrations reported for fish and point out the remarkable ability of Sábalo to feed on anthropogenic organic-enriched particles and tolerate a high pollutant load. Contaminant signatures show partial alteration with still abundant lower molecular weight components indicating that fish feeds directly in the outfalls. Consumption limits based on reference doses ranged from 0.1 (PCBs) to >12 000 g d⁻¹ (endosulfan) allowing a comprehensive risk-based ranking of contaminants in this long-range migrating, detritivorous fish.     

Immunotoxicity in ascidians: antifouling compounds alternative to organotins: III--the case of copper(I) and Irgarol 1051

After the widespread ban of TBT, due to its severe impact on coastal biocoenoses, mainly related to its immunosuppressive effects on both invertebrates and vertebrates, alternative biocides such as Cu(I) salts and the triazine Irgarol 1051, the latter previously used in agriculture as a herbicide, have been massively introduced in combined formulations for antifouling paints against a wide spectrum of fouling organisms. Using short-term (60 min) haemocyte cultures of the colonial ascidian Botryllus schlosseri exposed to various sublethal concentrations of copper(I) chloride (LC₅₀ = 281 μM, i.e., 17.8 mg Cu L⁻¹) and Irgarol 1051 (LC₅₀ > 500 μM, i.e., >127 mg L⁻¹), we evaluated their immunotoxic effects through a series of cytochemical assays previously used for organotin compounds. Both compounds can induce dose-dependent immunosuppression, acting on different cellular targets and altering many activities of immunocytes but, unlike TBT, did not have significant effects on cell morphology. Generally, Cu(I) appeared to be more toxic than Irgarol 1051: it significantly (p < 0.05) inhibited yeast phagocytosis at 0.1 μM (∼10 μg L⁻¹), and affected calcium homeostasis and mitochondrial cytochrome-c oxidase activity at 0.01 μM (∼1 μg L⁻¹). Both substances were able to change membrane permeability, induce apoptosis from concentrations of 0.1 μM (∼10 μg L⁻¹) and 200 μM (∼50 mg L⁻¹) for Cu(I) and Irgarol 1051, respectively, and alter the activity of hydrolases. Both Cu(I) and Irgarol 1051 inhibited the activity of phenoloxidase, but did not show any interactive effect when co-present in the exposure medium, suggesting different mechanisms of action.     

Aluminum water treatment residuals as permeable reactive barrier sorbents to reduce phosphorus losses

Two aluminum water treatment residuals (Al-WTRs) from water treatment plants in Manatee County, FL and Punta Gorda, FL were evaluated as potential permeable reactive barrier (PRB) media to reduce groundwater phosphorus (P) losses. Short-term (<24 h) P sorption kinetics and long-term P sorption capacity were determined using batch equilibration studies. Phosphorus desorption was characterized following P loadings of 10, 20, 30, 40 and >70 g kg⁻¹. Sorption and desorption studies were conducted on the <2.0 mm material and three size fractions within the <2.0 mm material. The effect of dissolved organic carbon (DOC) on P retention was determined by reacting Al-WTRs with P-spiked groundwater samples of varying initial DOC concentrations. Phosphorus sorption kinetics were rapid for all size fractions of both Al-WTRs (>98% P sorption effectiveness at shaking times ?2 h). The effect of DOC was minimal at <150 mg DOC L⁻¹, but modest reductions (<22%) in P sorption effectiveness occurred at 587 mg DOC L⁻¹. The P sorption capacities of the Manatee and Punta Gorda Al-WTRs (<2.0 mm) are ∼44 g kg⁻¹ and >75 g kg⁻¹, respectively, and the lifespan of an Al-WTR PRB is likely many decades. Desorption was minimal (<2% of the P sorbed) for cumulative P loadings <40 g kg^-l, but increased (<9% of the P sorbed) at cumulative P loads >70 g kg⁻¹. The <2.0 mm Manatee and Punta Gorda Al-WTRs are regarded as ideal PRB media for P remediation.     

Biological monitoring of chlorpyrifos exposure to rice farmers in Vietnam

Chlorpyrifos is the most common organophosphate insecticide registered for use in Vietnam and is widely used in agriculture, particularly rice farming. However, chlorpyrifos exposure to and adverse effects on farmers has not been evaluated. In this study, biological monitoring of chlorpyrifos exposure in a group of rice farmers was conducted after a typical application event using back-pack spraying.Urine samples (24 h) were collected from the rice farmers before and post insecticide application. Samples were analysed for 3,5,6-trichloropyridinol (TCP), the major urinary metabolite of chlorpyrifos, using an enzymatic pre-treatment before extraction followed by HPLC-MS/MS. Absorbed Daily Dose (ADD) of chlorpyrifos for farmers were then estimated from urinary TCP levels, expressed as μg g⁻¹ creatinine. The analytical method for urinary TCP had a low detection limit (0.6 μg L⁻¹), acceptable recovery values (80-114%), and low relative percentage differences in duplicate and repeated samples.Post-application chlorpyrifos ADD of farmers varied from 0.4 to 94.2 μg kg⁻¹ (body weight) d⁻¹ with a mean of 19.4 μg kg⁻¹ d⁻¹ which was approximately 80-fold higher than the mean baseline exposure level (0.24 μg kg⁻¹ d⁻¹). Hazard Quotients (ratio of the mean ADD for rice farmers to acute oral reference dose) calculated using acute oral reference doses recommended by United States and Australian agencies varied from 2.1 (Australian NRA), 4.2 (US EPA) to 6.9 (ATSDR).Biological monitoring using HPLC-MS/MS analysis of urinary TCP (24 h) was found to be an effective method for measuring chlorpyrifos exposure among farmers. This case study found that Vietnamese rice farmers had relatively high exposures to chlorpyrifos after application, which were likely to have adverse health effects.