The discharge of oil well produced water (PW) provides a constant source of contaminants to the marine environment including polycyclic aromatic hydrocarbons, alkylated phenols, metals and production chemicals. High concentrations of PW cause adverse effects to exposed biota, including reduced survival, growth and reproduction. Here we explore the effects of PW on immune function in the blue mussel, Mytilus edulis. Mussels were exposed for 21 days to sublethal PW concentrations (0.125-0.5%) and cellular parameters were measured. Cell viability, phagocytosis and cytotoxicity were inhibited after exposure to 0.25% and 0.5% PW, whilst the 0.125% PW treatment produced significant increases in these biomarker responses. This biphasic response was only observed after 7 days exposure; longer exposure periods led to a reduction in immune parameters. Results indicate that PW concentrations close to the discharge point cause modulation to cellular immunity. The implications for longer-term disease resistance are discussed. Exposure to produced water alters immune function in the sentinel species Mytilus edulis.

Although anthropogenic pollutants are thought to threaten reptilian species, there are few toxicity studies on reptiles. We evaluated the toxicity of Pb as lead acetate to the Western fence lizard (Sceloporus occidentalis). The acute lethal dose and sub-acute (14-day) toxicity studies were used to narrow exposure concentrations for a sub-chronic (60-day) study. In the sub-chronic study, adult and juvenile male lizards were dosed via gavage with 0, 1, 10 and 20 mg Pb/kg-bw/day. Mortality was limited and occurred only at the highest dose (20 mg Pb/kg-bw/d). There were statistically significant sub-lethal effects of 10 and 20 mg Pb/kg-bw/d on body weight, cricket consumption, organ weight, hematological parameters and post-dose behaviors. Of these, Pb-induced changes in body weight are most useful for ecological risk assessment because it is linked to fitness in wild lizard populations. The Western fence lizard is a useful model for reptilian toxicity studies. The Western fence lizard, Sceloporus occidentalis, is sensitive to Pb and is a useful laboratory model for ecotoxicological testing of reptiles.

The purpose of this study was to biomonitor metropolitan areas of Porto Alegre (Brazil) for PAHs associated with atmospheric particles and check their effects on the DNA of the land mollusk Helix aspersa. The sampling sites are located in an urban area with heavy traffic: (i) Canoas, (ii) Sapucaia do Sul, and (iii) FIERGS/Porto Alegre. The samples were collected during a continuous period of 24 hours during 15 days using Stacked Filter Units (SFU) on polycarbonate filters (two separated size fractions: PM10-2.5 and PM<2.5). The concentrations of 16 major PAHs were determined according to EPA. Comet assay on H. aspersa hemolymph cells was chosen for genotoxicity evaluation. This evaluation shows that, in general, the smaller PM-size fractions (PM<2.5) have the highest genotoxicity and contain higher concentrations of extractable organic matter. In addition, associations between chemical characteristics and PM carcinogenicity tend to be stronger for the smaller PM-size fractions. DNA damage in H. aspersa exposed to atmospheric particulate in Metropolitan Area of Porto Alegre demonstrated association with PAHs in the fine filter (PM<2.5).

Raman spectroscopy was used to investigate sorption mechanisms of cephapirin (CHP), a veterinary antibiotic, onto quartz (SiO₂) and feldspar (KAlSi₃O₈) at different pH. Sorption occurs by electrostatic attraction, monodentate and bidentate complexation. The zwitterion (CHP⁰) adsorbs to a quartz(+) surface by electrostatic attraction of the carboxylate anion group (-COO-) at low pH, but adsorbs to a quartz(-) surface through electrostatic attraction of the pyridinium cation, and possibly COO- bridge complexes, at higher pH. CHP- bonds to quartz(-) surfaces by bidentate complexation between one oxygen of -COO- and oxygen from carbonyl of an acetoxymethyl group. On a feldspar(+/-) surface, CHP⁰ forms monodentate complexes between CO, and possible -COO- bridges and/or electrostatic attachments to localized edge (hydr)oxy-Al surfaces. CHP- adsorbs to feldspar(-) through monodentate CO complexation. Similar mechanisms may operate for other cephalosporins. Results demonstrate, for the first time, that Raman techniques can be effective for evaluating sorption mechanisms of antibiotics. Raman spectroscopy indicates that cephapirin, a veterinary antibiotic, sorbs to quartz and feldspar by electrostatic attraction, and monodentate and bidentate complexation.

Structural and functional responses of a benthic macroinvertebrate assemblage to pulses of the insecticide imidacloprid were assessed in outdoor stream mesocosms. Imidacloprid pulses reduced invertebrate abundance and community diversity in imidacloprid-dosed streams compared to control streams. These results correlated well with effects of imidacloprid on leaf litter decomposition and feeding rates of Pteronarcys comstocki, a stonefly, in artificial streams. Reductions in oxygen consumption of stoneflies exposed to imidacloprid were also observed in laboratory experiments. Our findings suggest that leaf litter degradation and single species responses can be sensitive ecotoxicological endpoints that can be used as early warning indicators and biomonitoring tools for pesticide contamination. The data generated illustrates the value of mesocosm experiments in environmental assessment and how the consideration of functional and structural endpoints of natural communities together with in situ single species bioassays can improve the evaluation and prediction of pesticide effects on stream ecosystems. Combining organism-level responses with community-level processes for the evaluation and prediction of pesticide effects on stream ecosystems.

Despite heavy insecticide usage in urban areas, only a few studies have investigated the impact of current-use insecticides on benthic invertebrates in urban streams. The objective of this study was to measure the presence and concentration of current-use pesticides in sediments of residential streams in central Texas. Additionally, toxicity of these sediments to Hyalella azteca was evaluated. Sediment samples were collected from several sites in urban streams over the course of a year, of which, 66% had greater than one toxic unit (TU) of insecticide. Bifenthrin was the greatest contributor accounting for 65% of the TUs, and sediment toxicity to H. azteca correlated with the magnitude of total insecticides and bifenthrin TUs. The results of this study further raise concerns over the environmental consequences posed by many current-use insecticides, especially pyrethroids, in urban settings. This study examined the presence of insecticides in Texas stream sediments as a model for evaluating the potential impact of urban insecticide use in the Southern United States.

Fluoroquinolones like difloxacin (DIF) and sarafloxacin (SARA) are adsorbed in soil and enter the aquatic environment wherein they are subjected to photolytic degradation. To evaluate the fate of DIF and SARA, their photolysis was performed in water under stimulated natural sunlight conditions. DIF primarily degrades to SARA. On prolonged photodegradation, seven photoproducts were elucidated by HR-LC-MS/MS, three of which were entirely novel. The residual anti-bacterial activities of DIF, SARA and their photoproducts were studied against a group of pathogenic strains. DIF and SARA revealed potency against both Gram-positive and -negative bacteria. The photoproducts also exhibited varying degrees of efficacies against the tested bacteria. Even without isolating the individual photoproducts, their impact on the aquatic environment could be assessed. Therefore, the present results call for prudence in estimating the fate of these compounds in water and in avoiding emergence of resistance in bacteria caused by the photoproducts of DIF and SARA.

Limited information is available on the environmental behavior and associated potential risk of manufactured oxide nanoparticles (NPs). In this research, toxicity of nanoparticulate and bulk ZnO, Al2O3 and TiO2 were examined to the nematode Caenorhabditis elegans with Escherichia coli as a food source. Parallel experiments with dissolved metal ions from NPs were also conducted. The 24-h median lethal concentration (LC50) and sublethal endpoints were assessed. Both NPs and their bulk counterparts were toxic, inhibiting growth and especially the reproductive capability of the nematode. The 24-h LC50 for ZnO NPs (2.3 mg L-1) and bulk ZnO was not significantly different, but significantly different between Al2O3 NPs (82 mg L-1) and bulk Al2O3 (153 mg L-1), and between TiO2 NPs (80 mg L-1) and bulk TiO2 (136 mg L-1). Oxide solubility influenced the toxicity of ZnO and Al2O3 NPs, but nanoparticle-dependent toxicity was indeed observed for the investigated NPs. ZnO, Al2O3 and TiO2 nanoparticles are more toxic than their bulk counterparts to the nematode, Caenorhabditis elegans.

The deposition of chemical pollutants into roadside wetlands from runoff is a current environmental concern. In northern latitudes, a major pollutant in runoff water is salt (NaCl), used as de-icing agents. In this study, 26 roadside ponds were surveyed for amphibian species richness and chloride concentration. Acute toxicity tests (LC50) were performed on five locally common amphibian species using a range of environmentally significant NaCl concentrations. Field surveys indicated that spotted salamanders (Ambystoma maculatum) and wood frogs (Rana sylvatica) did not occupy high chloride ponds. American toads (Bufo americanus) showed no pond preference based on chloride concentration. Acute toxicity tests showed spotted salamanders and wood frogs were most sensitive to chloride, and American toads were the least. Spring peepers (Pseudacris crucifer) and green frogs (Rana clamitans) showed intermediate sensitivities. We concluded that chloride concentrations in ponds due to application of de-icing salts, influenced community structure by excluding salt intolerant species. Salt toxicity is presented as a mechanism affecting the distribution of amphibians and structure of amphibian communities in roadside wetlands.

Gannet (Morus bassanus) eggs from Bass Rock (North Sea) and Ailsa Craig (eastern Atlantic) were monitored for PCB congeners (1990-2004) and total mercury (1974-2004). Congener profiles for both colonies were dominated by PCBs 153, 138, 180, 118 and 170. All declined in concentration at Ailsa Craig but some (153, 170, 180) remained stable or increased slightly at Bass Rock. Egg congener concentrations at Bass Rock were typically 10-fold higher than at Ailsa Craig by 2002, and Principal Component Analysis indicated that colony differences were driven by the dominant congeners. Egg mercury concentrations were significantly lower at Bass Rock than at Ailsa Craig and temporal trends differed, there being a significant decline at Ailsa Craig but a marginal increase at Bass Rock. Our results suggest there may be differences in contamination between the eastern Atlantic and North Sea and/or there are colony differences in prey selection and associated contaminant loads. Monitoring of PCBs and Hg in gannet eggs reveals contrasting temporal patterns between colonies on the eastern Atlantic and North Sea coasts of Britain.