Parental effects manifest as alterations in offspring phenotype resulting from the parental phenotype and/or parental environment. We evaluated the effects of parental diet quality and mating strategy on the toxicant tolerance of offspring in Biomphalaria glabrata snails. We raised snails either individually (self-fertilizing) or in groups of three (outcrossing) on a diet of uncooked lettuce, fish food, cooked lettuce, or cooked lettuce plus fish food. We then exposed their offspring to cadmium and malathion challenges. Cadmium tolerance varied with parental diet and was greater in the offspring of outcrossing snails than self-fertilizing snails. Malathion tolerance was not affected by parental diet but was greater in the offspring of outcrossing snails. These results indicate that offspring responses to stressors are heavily influenced by parental experience, but may depend on the specific stressor and the mechanism of action and/or detoxification.

Mercury (Hg) is a globally ubiquitous pollutant that has received much attention due to its toxicity to humans and wildlife. The development of non-destructive sampling techniques is a critical step for sustainable monitoring of Hg accumulation. We evaluated the efficacy of non-destructive sampling techniques and assessed spatial, temporal, and demographic factors that influence Hg bioaccumulation in turtles. We collected muscle, blood, nail, and eggs from snapping turtles (Chelydra serpentina) inhabiting an Hg contaminated river. As predicted, all Hg tissue concentrations strongly and positively correlated with each other. Additionally, we validated our mathematical models against two additional Hg contaminated locations and found that tissue relationships developed from the validation sites did not significantly differ from those generated from the original sampling site. The models provided herein will be useful for a wide array of systems where biomonitoring of Hg in turtles needs to be accomplished in a conservation-minded fashion.

We reviewed 122 peer-reviewed studies on the effects of organic toxicants and heavy metals on three fundamental ecosystem functions in freshwater ecosystems, i.e. leaf litter breakdown, primary production and community respiration. From each study meeting the inclusion criteria, the concentration resulting in a reduction of at least 20% in an ecosystem function was standardized based on median effect concentrations of standard test organisms (i.e. algae and daphnids). For pesticides, more than one third of observations indicated reductions in ecosystem functions at concentrations that are assumed being protective in regulation. Moreover, the reduction in leaf litter breakdown was more pronounced in the presence of invertebrate decomposers compared to studies where only microorganisms were involved in this function. High variability within and between studies hampered the derivation of a concentration–effect relationship. Hence, if ecosystem functions are to be included as protection goal in chemical risk assessment standardized methods are required.

Nanoscale zerovalent iron (nZVI) has potential for the remediation of organochlorine-contaminated environments. Environmental safety concerns associated with in situ deployment of nZVI include potential negative impacts on indigenous microbes whose biodegradative functions could contribute to contaminant remediation. With respect to a two-step polychlorinated biphenyl remediation scenario comprising nZVI dechlorination followed by aerobic biodegradation, we examined the effect of polyacrylic acid (PAA)-coated nZVI (mean diameter = 12.5 nm) applied at 10 g nZVI kg−1 to Aroclor-1242 contaminated and uncontaminated soil over 28 days. nZVI had a limited effect on Aroclor congener profiles, but, either directly or indirectly via changes to soil physico-chemical conditions (pH, Eh), nZVI addition caused perturbation to soil bacterial community composition, and reduced the activity of chloroaromatic mineralizing microorganisms. We conclude that nZVI addition has the potential to inhibit microbial functions that could be important for PCB remediation strategies combining nZVI treatment and biodegradation.

The environmental dioxin 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is classified as a Group 1 human carcinogen and teratogenic agent. We hypothesize that TCDD-induced oxidative stress may also interfere with mitochondrial ATP-sensitive potassium channels (mitoKATP), which are known to regulate and to be regulated by mitochondrial redox state. We investigated the effects of an acute treatment of male Wistar rats with TCDD (50 μg/kg i.p.) and measured the regulation of cardiac mitoKATP. While the function of cardiac mitochondria was slightly depressed, mitoKATP activity was 52% higher in animals treated with TCDD. The same effects were not observed in liver mitochondria isolated from the same animals. Our data also shows that regulation of mitochondrial ROS production by mitoKATP activity is different in both groups. To our knowledge, this is the first report to show that TCDD increases mitoKATP activity in the heart, which may counteract the increased oxidative stress caused by the dioxin during acute exposure.

This study investigated the ability of natural river biofilms from different seasons to degrade the carbamate pesticides methomyl, carbaryl and carbofuran in single and multiple pesticide systems, and the effects of these pesticides on algal and bacterial communities within biofilms. Spring biofilms had the lowest biomass of algae and bacteria but showed the highest methomyl degradation (>99%) and dissipation rates, suggesting that they might contain microorganisms with high methomyl degradation abilities. Degradation of carbofuran (54.1–59.5%) by biofilms in four seasons was similar, but low degradation of carbaryl (0–27.5%) was observed. The coexistence of other pesticides was found to cause certain effects on pesticide degradation and primarily resulted in lower diversity of diatoms and bacteria than when using a single pesticide. The tolerant diatoms and bacteria potentially having the ability to degrade test pesticides were identified. River biofilms could be suitable biomaterials or used to isolate degraders for bioremediating pesticide-contaminated water.

To assess the severity of oil spills on mangroves, diagnosis of the vegetation health is crucial. Some aspects of photosynthesis such as photochemical efficiency and leaf pigment composition together with the level of oxidative stress may constitute reliable indicators for vegetation health. To test this approach 14 month old Laguncularia racemosa were contaminated with 5 L m−2 of the marine fuel oil MF-380 and treated with an oil degrading bacterial consortium in microcosms. Contamination resulted in a 20% decrease in shoot dry weight after 128 days. Photochemical efficiency, pigment content, catalase and ascorbate peroxidase remained unchanged. Multivariate ordination of DGGE microbial community fingerprints revealed a pronounced separation between the oil contaminated and the non-contaminated samples. Further studies are necessary before physiological parameters can be recommended as indicators for plant's health in oil polluted mangroves.

The vast use of silver nanoparticles (AgNPs) mandates thorough investigation of their impact on biosystems at various levels. The cytotoxicity of PVP coated-AgNPs to pollen, the aploid male gametophyte of higher plants, has been assessed here for the first time. The negative effects of AgNPs include substantial decreases in pollen viability and performance, specific ultrastructural alterations, early changes in calcium content, and unbalance of redox status. Ag+ released from AgNPs damaged pollen membranes and inhibited germination to a greater extent than the AgNPs themselves. By contrast, the AgNPs were more potent at disrupting the tube elongation process. ROS deficiency and overproduction were registered in the Ag+- and AgNP-treatment, respectively. The peculiar features of AgNP toxicity reflected their specific modes of interaction with pollen surface and membranes, and the dynamic exchange between coating (PVP) and culture medium. In contrast, the effects of Ag+ were most likely induced through chemical/physicochemical interactions.

MicroResp™ is a miniaturised method for measuring substrate induced respiration (SIR) in soil. We modified the MicroResp™ method to develop a rapid tool for quantifying the ecotoxicological impact of contaminants. The method is based on reduction in SIR across a gradient of contaminant, allowing for determination of dose–response curves EC-values. Contaminants are mixed into soil samples at a range of concentrations; each sample is then dispensed into a column of eight wells in 96 well format (deep) plates. Moisture and glucose are added to the samples at levels to provide maximum response. Released CO2 from the soils is then measured using colorimetric gel-traps, following the standard MicroResp™ methodology. Examination revealed that this method works over a range of soil types and is insensitive to minor variations in assay length (2–7 h), alteration of moisture content (±20 μL from optimum), and soil storage conditions (4 °C versus fresh).

Using the marine rotifer Brachionus plicatilis acute toxicity tests, we estimated the toxicity of Corexit 9500A®, propylene glycol, and Macondo oil. Ratios of 1:10, 1:50 and 1:130 for Corexit 9500A®:Macondo oil mixture represent: maximum exposure concentrations, recommended ratios for deploying Corexit (1:10–1:50), 1:130 the actual dispersant:oil ratio used in the Deep Water Horizon spill. Corexit 9500A® and oil are similar in their toxicity. However, when Corexit 9500A® and oil are mixed, toxicity to B. manjavacas increases up to 52-fold. Extrapolating these results to the oil released by the Macondo well, suggests underestimation of increased toxicity from Corexit application. We found small differences in sensitivity among species of the B. plicatilis species complex, likely reflecting phylogenetic similarity. Just 2.6% of the water-accommodated fraction of oil inhibited rotifer cyst hatching by 50%, an ecologically significant result because rotifer cyst in sediments are critical resources for the recolonization of populations each Spring.