Increased concentrations of polycyclic aromatic hydrocarbons in Alpine streams during annual snowmelt: investigating effects of sampling method, site characteristics, and meteorology.

Silicone passive samplers and macroinvertebrates were used to measure time-integrated concentrations of polycyclic aromatic hydrocarbons (PAHs) in alpine streams during annual snowmelt. The three sampling sites were located near a main highway in Arthur's Pass National Park in the Southern Alps of New Zealand. A similar set of PAH congeners, composed of 2-4 rings, were found in silicone passive samplers and macroinvertebrates. The background PAH concentrations were similar at all sites, implying that proximity to the highway did not affect concentrations. In passive samplers, an increase of PAH concentrations by up to seven times was observed during snowmelt. In macroinvertebrates, the concentration changes were moderate; however, macroinvertebrate sampling did not occur during the main pulse observed in the passive samplers. The extent of vegetation in the catchment appeared to affect the concentration patterns seen at the different stream sites. A strong correlation was found between PAH concentrations in passive samplers and the amount of rainfall in the study area, indicating that the washout of contaminants from snowpack by rainfall was an important process.

Interspecific effects of 4A-DNT (4-amino-2,6-dinitrotoluene) and RDX (1,3,5-trinitro-1,3,5-triazine) in Japanese quail, Northern bobwhite, and Zebra finch.

The purpose of this study was to assess the toxicological effects of two munition compounds, 4-amino-2,6-dinitrotoluene (4A-DNT) and 1,3,5-trinitro-1,3,5-triazine (RDX), on three different bird species: two common toxicological model species-the Northern Bobwhite (Colinus virginianus) and the Japanese Quail (Coturnix japonica), and a representative passerine-the Zebra Finch (Taeniopygia guttata). Bobwhite were exposed to 4A-DNT at 0, 8, 15, 30, 60, or 150 mg/kg body weight (bw) d by oral gavage for seven days; because the high dose of 4A-DNT was lethal to bobwhite, the maximum dose was changed to 100 mg/kg bw d for Japanese quail and finches to ensure tissue could be used for future toxicogenomic work. RDX was similarly administered at 0, 0.5, 1.5, 3, 6, or 12 mg/kg bw d. Blood was drawn prior to euthanasia for blood cellularity and chemistry analyses. Finches were clearly least affected by 4A-DNT as evidenced by a lack of observable effects. Bobwhite appeared to be the most sensitive species to 4A-DNT as observed through changes in blood cellularity and plasma chemistry effects. Bobwhite appeared to be more sensitive to RDX than Japanese Quail due to increased effects on measures of plasma chemistries. Finches exhibited the greatest sensitivity to RDX through increased mortality and seizure activity. This study suggests that sensitivity among species is chemical-specific and provides data that could be used to refine current avian sensitivity models used in ecological risk assessments.

The effects of the herbicide metolachlor on agonistic behavior in the crayfish, Orconectes rusticus.

Previous research suggests that agricultural herbicides interfere with olfactory-mediated behavior, such as responses to alarm signals and the ability to locate food, in aquatic organisms. In crayfish, aggressive interactions are also mediated by chemical signals. These social signals are important in establishing dominance, which in turn has an impact on an individual's ability to find and use mates, food, and habitat space. In this study, we investigated the impact of exposure to sublethal levels of the herbicide metolachlor on the ability of crayfish to respond to olfactory signals used in agonistic behaviors. Crayfish were exposed to three different environmentally relevant concentrations (60 ppb, 70 ppb, and 80 ppb) of metolachlor for 96 hours. Each exposed crayfish was then placed in a fight arena and was allowed to interact with a naïve, untreated crayfish for 15 minutes. We analyzed several characteristics of fighting behavior, including initial aggressiveness, time to fight, intensity levels, duration, number of encounters, and the winner and loser of each fight. Crayfish exposed to 80 ppb metolachlor were less likely to initiate and win encounters against naïve conspecifics than any other treatment group. Analysis of fight dynamics shows that metolachlor does not alter the temporal fighting dynamics within crayfish aggression. We conclude that high sublethal concentrations of metolachlor may be interfering with the ability of crayfish to receive or respond to social signals and thus affect certain agonistic behaviors.