Skin is a major by-product of the fisheries and aquaculture industries and is a valuable source of gelatin. This study examined the effect of triploidization on gelatin yield and proximate composition of the skin of African catfish (Clarias gariepinus). We further investigated the effects of two commonly used pesticides, chlorpyrifos (CPF) and butachlor (BUC), on the skin gelatin yield and amino acid composition in juvenile full-sibling diploid and triploid African catfish. In two separate experiments, diploid and triploid C. gariepinus were exposed for 21 days to graded CPF [mean measured: 10, 16, or 31 μg/L] or BUC concentrations [Mean measured: 22, 44, or 60 μg/L]. No differences in skin gelatin yield, amino acid or proximate compositions were observed between diploid and triploid control groups. None of the pesticide treatments affected the measured parameters in diploid fish. In triploids, however, gelatin yield was affected by CPF treatments while amino acid composition remained unchanged. Butachlor treatments did not alter any of the measured variables in triploid fish. To our knowledge, this study is the first to investigate changes in the skin gelatin yield and amino acid composition in any animal as a response to polyploidization and/or contaminant exposure.

The worldwide use of pesticides has led to increases in agricultural yields by reducing crop losses. However, increased pesticide use has resulted in pesticide-resistant pest species and recent studies have discovered pesticide-resistance in non-target species living close to farms. Such increased tolerance not only affects the species, but can alter the entire food web. Given that some species can evolve not only resistance to a single pesticide, but also cross-resistance to other pesticides that share the same mode of action, one would predict that cross-resistance to pesticides would also have effects on the entire community and affect community stability. To address this hypothesis, we conducted an outdoor mesocosm experiment comprised of 200 identical aquatic communities with phytoplankton, periphyton, and leopard frog (Lithobates pipiens) tadpoles. To these communities, we added one of four Daphnia pulex populations that we previously discovered were either resistant or sensitive to the insecticide of chlorpyrifos as a result of living close to or far from agriculture, respectively. We then exposed the communities to either no insecticide or three different concentrations of AChE-inhibiting insecticides (chlorpyrifos, malathion or carbaryl) or sodium channel-inhibiting insecticides (permethrin or cypermethrin). We discovered that communities containing sensitive Daphnia pulex experienced phytoplankton blooms and subsequent cascades through all trophic groups including amphibians at moderate to high concentrations of all five insecticides. However, communities containing resistant D. pulex were buffered from these effects at low to moderate concentrations of all AChE-inhibiting insecticides, but were not buffered against the pyrethroid insecticides. These data suggest that a simple change in the population-level resistance of zooplankton to a single insecticide can have widespread consequences for community stability and that the effects can be extrapolated to a wide variety of pesticides that share the same mode of action.

In this study, we conducted a 14-month investigation in Daya Bay, southern China to understand the effects of oyster farming on phytoplankton community and biomass by using size-fractionated phytopigments. Results proved the filtering effects of oysters on phytoplankton biomass. During the oyster culture period, the average concentration of total chlorophyll a (sum of size-fractionated Chl a) within the farming area was approximately 60% lower than that at the reference site. Phytoplankton depletion in the aquaculture zone mainly occurred in micro-sized fractions (>20 μm) of Chl a, fucoxanthin, and peridinin. The influence of oyster filtration on nano-sized (2.7–20 μm) pigments seemed less than that on micro-sized ones. The depletion of peridinin and 19′-hex-fucoxanthin in aquaculture zone was higher than those of the other pigments, which indicated that flagellated cells might be selectively filtered by oysters and could be more easily influenced by oyster aquaculture. The pico-sized Chl a (<2.7 μm) comprised 24% of total Chl a on the average in the aquaculture zone during the cultural period compared to 6% in the reference site. Picoeukaryote abundance, which was determined via flow cytometry, was significantly higher in the aquaculture zone than in the non-aquaculture areas. The abundance of picoeukaryote is significantly and positively correlated with the concentrations of pico-sized prasinoxanthin, violaxanthin, and neoxanthin, indicating that picoeukaryote is dominated by those in prasinophyte. The results suggest that oyster aquaculture might stimulate the growth of prasinophyte, although the seasonal variations are mainly controlled by the water temperature in the study area. This research highlights the successful use of size-fractionated phytopigments to estimate size-specific phytoplankton biomass and community, which can be applied as a routine method to monitor the environmental effect and food resources of bivalve aquaculture.

Heavy metal pollution is a global issue severely constraining aquaculture practices, not only deteriorating the aquatic environment but also threatening the aquaculture production. One promising solution is adopting aquaponics systems where a synergy can be established between aquaculture and aquatic plants for metal sorption, but the interactions of multiple metals in such aquatic plants are poorly understood. In this study, we investigated the absorption behaviors of Cu(II) and Cd(II) in water by water hyacinth roots in both single- and binary-metal systems. Cu(II) and Cd(II) were individually removed by water hyacinth roots at high efficiency, accompanied with release of protons and cations such as Ca2+ and Mg2+. However, in a binary-metal arrangement, the Cd(II) sorption was significantly inhibited by Cu(II), and the higher sorption affinity of Cu(II) accounted for its competitive sorption advantage. Ionic exchange was identified as a predominant mechanism of the metal sorption by water hyacinth roots, and the amine and oxygen-containing groups are the main binding sites accounting for metal sorption via chelation or coordination. This study highlights the interactive impacts of different metals during their sorption by water hyacinth roots and elucidates the underlying mechanism of metal competitive sorption, which may provide useful implications for optimization of phytoremediation system and development of more sustainable aquaculture industry.

The enrichment of soil arsenic (As) and antimony (Sb) is putting increasing pressure on the environment and human health. The biogeochemical behaviour of Sb and its uptake mechanisms by plants are poorly understood and generally assumed to be similar to that of As. In this study, the lability of As and Sb under agricultural conditions in historically contaminated soils was assessed. Soils were prepared by mixing historically As and Sb-contaminated soil with an uncontaminated soil at different ratios. The lability of As and Sb in the soils was assessed using various approaches: the diffusive gradients in thin films technique (DGT) (as CDGT), soil solution analysis, and sequential extraction procedure (SEP). Lability was compared to the bioaccumulation of As and Sb by various compartments of radish (Raphanus sativus) grown in these soils in a pot experiment. Irrespective of the method, all of the labile fractions showed that both As and Sb were firmly bound to the solid phases, and that Sb was less mobile than As, although total soil Sb concentrations were higher than total soil As. The bioassay demonstrated low bioaccumulation of As and Sb into R. sativus due to their low lability of As and Sb in soils and that there are likely to be differences in their mechanisms of uptake. As accumulated in R. sativus roots was much higher (2.5–21 times) than that of Sb, while the Sb translocated from roots to shoots was approximately 2.5 times higher than that of As. As and Sb in R. sativus tissues were strongly correlated with their labile concentrations measured by DGT, soil solution, and SEP. These techniques are useful measures for predicting bioavailable As and Sb in the historically contaminated soil to R. sativus. This is the first study to demonstrate the suitability of DGT to measure labile Sb in soils.

Among urban stormwater pollutants, hydrocarbons are a significant environmental concern due to their toxicity and relatively stable chemical structure. This study focused on the identification of hydrocarbon contributing sources to urban road dust and approaches for the quantification of pollutant loads to enhance the design of source control measures. The study confirmed the validity of the use of mathematical techniques of principal component analysis (PCA) and hierarchical cluster analysis (HCA) for source identification and principal component analysis/absolute principal component scores (PCA/APCS) receptor model for pollutant load quantification. Study outcomes identified non-combusted lubrication oils, non-combusted diesel fuels and tyre and asphalt wear as the three most critical urban hydrocarbon sources. The site specific variabilities of contributions from sources were replicated using three mathematical models. The models employed predictor variables of daily traffic volume (DTV), road surface texture depth (TD), slope of the road section (SLP), effective population (EPOP) and effective impervious fraction (EIF), which can be considered as the five governing parameters of pollutant generation, deposition and redistribution. Models were developed such that they can be applicable in determining hydrocarbon contributions from urban sites enabling effective design of source control measures.

With the increasing use of treated wastewater and biosolids in agriculture, residues of pharmaceutical and personal care products (PPCPs) in these reused resources may contaminate food produce via plant uptake, constituting a route for human exposure. Although various PPCPs have been reported to be taken up by plants in laboratories or under field conditions, at present little information is available on their metabolism in plants. In this study, we applied carrot cell cultures to investigate the plant metabolism of PPCPs. Five phase I metabolites of carbamazepine were identified and the potential metabolism pathways of carbamazepine were proposed. We also used the carrot cell cultures as a rapid screening tool to initially assess the metabolism potentials of 18 PPCPs. Eleven PPCPs, including acetaminophen, caffeine, meprobamate, primidone, atenolol, trimethoprim, DEET, carbamazepine, dilantin, diazepam, and triclocarban, were found to be recalcitrant to metabolism. The other 7 PPCPs, including triclosan, naproxen, diclofenac, ibuprofen, gemfibrozil, sulfamethoxazole, and atorvastatin, displayed rapid metabolism, with 0.4–47.3% remaining in the culture at the end of the experiment. Further investigation using glycosidase hydrolysis showed that 1.3–20.6% of initially spiked naproxen, diclofenac, ibuprofen, and gemfibrozil were transformed into glycoside conjugates. Results from this study showed that plant cell cultures may be a useful tool for initially exploring the potential metabolites of PPCPs in plants as well as for rapidly screening the metabolism potentials of a variety of PPCPs or other emerging contaminants, and therefore may be used for prioritizing compounds for further comprehensive evaluations.

Exposure to phthalates has been found to have adverse effects on male reproductive function in animals. However, the findings from human studies are inconsistent. Here we examined the associations of phthalate exposure with semen quality and reproductive hormones in a Chinese population using phthalate metabolite concentrations measured in semen as biomarkers. Semen (n = 687) and blood samples (n = 342) were collected from the male partners of sub-fertile couples who presented to the Reproductive Center of Tongji Hospital in Wuhan, China. Semen quality parameters and serum reproductive hormone levels were determined. Semen concentrations of 8 phthalate metabolites were assessed using high-performance liquid chromatography and tandem mass spectrometry. Associations of the semen phthalate metabolites with semen quality parameters and serum reproductive hormones were assessed using confounder-adjusted linear and logistic regression models. Semen phthalate metabolites were significantly associated with decreases in semen volume [mono-n-butyl phthalate (MBP), mono-(2-ethylhexyl) phthalate (MEHP), mono(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), mono(2-ethyl-5-oxohexyl) phthalate (MEOHP)], sperm curvilinear velocity [monobenzyl phthalate (MBzP), MEHP, the percentage of di-(2-ethylhexyl)-phthalate metabolites excreted as MEHP (%MEHP)], and straight-line velocity (MBzP, MEHP, %MEHP), and also associated with an increased percentage of abnormal heads and tails (MBzP) (all p for trend <0.05). These associations remained suggestive or significant after adjustment for multiple testing. There were no significant associations between semen phthalate metabolites and serum reproductive hormones. Our findings suggest that environmental exposure to phthalates may impair human semen quality.

Motor vehicle emissions are increasingly becoming one of the important factors affecting the urban air quality in China. It is necessary and useful to policy makers to demonstrate the situation given the relevant pollutants reduction measures are taken. This paper predicted the reduction potentials of conventional pollutants (PM10, NOx, CO, HC) under different control strategies and policies in the Beijing-Tianjin-Hebei (BTH) region during 2011–2020. There are the baseline and 5 control scenarios designed, which presented the different current and future possible vehicular emissions control measures. Future population of different kinds of vehicles were predicted based on the Gompertz model, and vehicle kilometers travelled estimated as well. After that, the emissions reduction under the different scenarios during 2011–2020 could be estimated using emission factors and activity level data. The results showed that, the vehicle population in the BTH region would continue to grow up, especially in Tianjin and Hebei. Comparing the different scenarios, emission standards updating scenario would achieve a substantial reduction and keep rising up for all the pollutants, and the scenario of eliminating high-emission vehicles can reduce emissions more effectively in short-term than in long-term, especially in Beijing. Due to the constraints of existing economical and technical level, the reduction effect of promoting new energy vehicles would not be significant, especially given the consideration of their lifetime impact. The reduction effect of population regulation scenario in Beijing cannot be ignorable and would keep going up for PM10, CO and HC, excluding NOx. Under the integrated scenario considering all the control measures it would achieve the maximum reduction potential of emissions, which means to reduce emissions of PM10, NOx, CO, HC, by 56%, 59%, 48%, 52%, respectively, compared to BAU scenario for the whole BTH region in 2020.

Concentrations and patterns of hydroxylated (OH) polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) were investigated in liver from arctic foxes (Vulpes lagopus) sampled from Svalbard 1997–2011 (n = 100). The most important OH-PBDE in the arctic foxes was 6-OH-BDE47 detected in 24% of the samples. Relationships between 6-OH-BDE47, δ13C and BDE47 suggest that 6-OH-BDE47 residues in arctic foxes are related to marine dietary input, while the relative importance of the metabolic/natural origin of this compound remains unclear. 4-OH-CB187 and 4-OH-CB146 were the main OH-PCBs among the analyzed compounds. The OH-PCB pattern in the present arctic foxes indicates that arctic foxes have a capacity to biotransform a wide range of PCBs of different structures. Formation and retention of OH-PCBs was tightly related to PCB exposure. Furthermore, ΣOH-PCB concentrations were four times higher in the leanest compared to the fattest foxes. Concentrations of 4-OH-CB187 and 4-OH-CB146 among the highest contaminated arctic foxes were similar to the previously reported concentrations for polar bears. Given the high endocrine disruptive potential of OH-PCBs, we suggest that endocrine system may be affected by the relatively high OH-PCB residues in the Svalbard arctic fox population.