Jerry L. Farris

Transport and fate of atrazine and lambda-cyhalothrin in an agricultural drainage ditch in the Mississippi Delta, USA

Drainage ditches are integral components of agricultural production landscape, yet their contaminant mitigation capacity has been scarcely examined. If ditches are indeed capable of contaminant mitigation, then their use may serve as an alternative agricultural best management practice (BMP). A 50 m portion of an agricultural drainage ditch, located in the Mississippi Delta Management Systems Evaluation Area (MDMSEA), USA, was amended with a mixture of water, atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine) (herbicide) and lambda-cyhalothrin (-cyano-3-phenoxybenzyl-3-(2chloro-3,3,3-trifluoroprop-1-enyl)-2,2-dimethyl cyclopropanecarboxylate) (insecticide), simulating a storm runoff event. Pesticide amendment was achieved using a diffuser to disperse the mixture at an inflow point along the ditch (designated as “0 m”). Pesticide concentrations in water, sediment, and plants were monitored for 28 days. One hour following initiation of simulated runoff, mean percentages of atrazine concentrations measured in water and sediment were 37 and 2%, respectively, while mean percentages of lambda-cyhalothrin concentrations in water and sediment were 12 and 1%, respectively. Atrazine and lambda-cyhalothrin mean percentage concentrations in plants (Polygonum(water smartweed), Leersia(cutgrass), and Sporobolus (smutgrass)) were 61 and 87%, respectively. Therefore, plants serve as an important site for pesticide sorption during runoff events. Aqueous concentrations of both pesticides decreased to levels which would not elicit non-target toxicological effects by the end of the 50 m portion of the drainage ditch. This research provides fundamental answers concerning the capability of vegetated agricultural drainage ditches to mitigate pesticide-associated storm water runoff. Published by Elsevier Science B.V.

Bioaccumulation and trophic transfer of polychlorinated biphenyls by aquatic and terrestrial insects to tree swallows (Tachycineta bicolor)

Insectivorous passerines often bioaccumulate polychlorinated biphenyls (PCBs) via trophic transfer processes. Tree swallows (Tachycineta bicolor) frequently are used for estimating PCB bioaccumulation, yet the focus on specific trophic links between contaminated sediment and bird has been limited. Bioaccumulation of PCBs from sediment to tree swallows was examined with focus on trophic pathways by simultaneously examining PCBs in emergent aquatic and terrestrial insects and gut contents of nestlings. Total PCB concentrations increased from sediment (123.65 +/- 15.93 microg/kg) to tree swallow nestlings (2,827.76 +/- 505.67 microg/kg), with emergent aquatic insects, terrestrial insects, and gut content samples having intermediate concentrations. Biota-sediment accumulation factors (BSAFs) varied among congeners for tree swallow nestlings and for male and female Chironomus spp. For nestlings, the highest BSAF was for the mono-ortho-substituted congener 118. Nestling biomagnification values were similar for gut contents and female Chironomus spp., suggesting this diet item may be the main contributor to the overall PCB transfer to nestlings. However, gut content samples were highly variable and, on a PCB congener pattern basis, may have been influenced by other taxa, such as terrestrial insects. Considering dietary plasticity of many insectivorous birds, the present study suggests that a variety of potential food items should be considered when examining PCB accumulation in insectivorous passerines.

Growth of Asiatic clams (Corbicula sp.) during and after long-term zinc exposure in field-located and laboratory artificial streams

Juvenile and adult Asiatic clams were exposed to 0.025-1.0 mg Zn/L for 30 days in artificial stream systems in an outdoor field laboratory and formal laboratory setting. All exposures (≧0.050 mg/L), except 0.025 mg/L, significantly reduced total weight gain between days 20 to 30 in the field-laboratory experiments. Laboratory exposures yielded little growth information as nutritional needs of the clam were not adequately satisfied; therefore, further research was confined to the field location. Exposures to 1.0 mg/L resulted in 10-50% mortality by day 30 in outdoor artificial streams. Significant increases in tissue water content of Zn-exposed clams indicated tissue degradation or osmoregulatory impairment. Bioaccumulation of Zn occurred at all levels of exposure and reflected growth inhibition at the levels tested. The maximum accumulation occurred in 1.0 mg/L treated clams (2000 Μg Zn/g dry weight). Controls varied consistently around 200 Μg Zn/g dry weight. When clams exposed to Zn (0.050-1.0 mg/L) were removed from exposure to control streams, Zn was completely depurated in 17 days with a concomitant return to normal growth patterns. Clams from the higher Zn exposures (0.50 and 1.0 mg/L) remained significantly different from controls due to earlier growth inhibition by Zn.Corbicula is a sensitive indicator of Zn stress at levels that are currently considered protective of aquatic life.

Freshwater Bivalve Ecotoxicology

Freshwater Bivalve Ecotoxicology, J.L. Farris and J.H. Van Hassel A Review of the Use of Unionid Mussels as Biological Indicators of Ecosystem Health, J.H. Van Hassel and J.L. Farris A Brief Look at Freshwater Mussel (Unionacea) Biology, G.T. Watters Propagation and Culture of Freshwater Mussels, C.D. Bishop, R. Hudson, and J.L. Farris Laboratory Toxicity Testing with Freshwater Mussels, C.G. Ingersoll, N.J. Kernaghan, T.S. Gross, C.D. Bishop, N. Wang, and A. Roberts In-Situ Toxicity Testing of Unionids, M.Y. Armstead and J.L. Yeager Unionid Mussel Sensitivity to Environmental Contaminants, A. Keller, M. Lydy and D.S. Ruessler Toxicokinetics of Environmental Contaminants in Freshwater Bivalves, W.A. Thorsen, W.G. Cope, and D. Shea Linking Bioaccumulation and Biological Effects to Chemicals in Water and Sediment: A Conceptual Framework for Freshwater Bivalve Ecotoxicology, M.H. Salazar and S.M. Salazar Biomarker Responses of Unionid Mussels to Environmental Contaminants, T.J. Newton and W.G. Cope Case Study: Comparison of Asian Clam (Corbicula fluminea) In Situ Testing to Several Nontarget Test Organism Responses to Biocidal Dosing at a Nuclear Power Plant, D.S. Cherry and D.J. Soucek Case Study: Discrimination of Factors Affecting Unionid Mussel Distribution in the Clinch River, Virginia, USA, J.H. Van Hassel Case Study: Impact of Partially Treated Mine-Water on an Ohio River (USA) Mussel Bed: Use of Multiple Lines of Evidence in Impact Analysis, H.L. Dunn, J.L. Farris, and J.H. Van Hassel Case Study: Sensitivity of Mussel Glochidia and Regulatory Test Organisms to Mercury and a Reference Toxicant, T.W. Valenti, D.S. Cherry, R.J. Neves, B.A. Locke, and J.J. Schmerfeld

Effects of diet, water hardness, and population source on acute and chronic copper toxicity toCeriodaphnia dubia

The effects of diet, water hardness, and population source on acute toxicity, and diet and water hardness on chronic toxicity of copper (Cu) toCeriodaphnia dubia were evaluated. A diet of three algae (Chlamydomonas rheinhardti, Ankistrodesmus falcatus, and Chlorella vulgaris, hereafter referred to as CAC) cultured in vitaminenriched media was superior to synthetic diets consisting of yeast, Cerophyll, and trout chow (YCT). Neonates from mothers reared on CAC were 1.4 to 1.5 times more resistant to Cu than those reared on YCT or yeast and Cerophyll (YC). Forty-eight hr LC50s of Cu toC. dubia increased from 35 to 79 μg/L at water hardness of 94 and 170 mg CaCO3/L. Three populations ofCeriodaphnia derived from three USEPA (United States Environmental Protection Agency) laboratories showed no differential Cu sensitivity. Chronic Cu impairment was measured by neonate production in the 7-day life-cycle test. Chronic values were 7.9 and 10.1 μg/L at water hardnesses of 94 and 170 mg/L respectively. A comparison of daily water renewal and renewal on days 3 and 5 only was made. Neonate production was significantly greater using day 3 and 5 renewals (Friedmanns Rank Sum Test, p < 0.005), even though Cu concentrations were comparable between the two tests. Therefore, handling stress may have been incurred using daily changes. It is recommended that future tests and USEPA guidelines should address deleting YCT and including multi-algal diets for culturing and chronic testing ofCeriodaphnia.

The influence of water quality on macroinvertebrate community responses to copper in outdoor experimental streams

Abstract Experiments were conducted in artificial streams to examine the influence of water quality on macroinvertebrate community responses to copper (Cu). Macroinvertebrate communities were established on substratum-filled trays placed in the Clinch River and transferred to two artificial stream systems (New River and Clinch River streams) receiving water from different sources. Alkalinity and hardness in Clinch River (CR) streams were ∼2–3 times greater than in New River (NR) streams. Results of ANCOVA indicated that effects of Cu were greater in NR than in CR streams. After 4 days, total macroinvertebrate abundance was reduced by 32% in NR streams at 6 μg Cu/l but only by 25% in CR streams at 15 μg Cu/l. After 10 days, Tanytarsini chironomids, the dominant and most sensitive organisms collected, were eliminated from NR streams at 13 μg Cu/l but reduced by only 35% in CR streams at similar Cu levels. Results of canonical discriminant analysis also revealed greater impact of Cu in NR streams. After 10 days, macroinvertebrate communities in NR streams at 9 μg Cu/l were similar to those in CR streams at 24 μg Cu/l. Responses to Cu in both experimental streams and at impacted field sites were highly variable among taxa. Orthocladiini chironomids and net-spinning caddisflies were quite tolerant of Cu in experimental streams and were the only groups that recovered in the field. Our results demonstrate the importance of accounting for both water quality and composition of the resident fauna for establishing site-specific water quality criteria.

The influence of stream habitat and water quality on macroinvertebrate communities in degraded streams of northwest Mississippi

Streams in the loess hills of northwest Mississippi have undergone dramatic physical changes since European settlement and both physical and water quality processes may play a role in influencing biotic communities of these stream systems. The objectives of this study were to identify the response of macroinvertebrate taxa to water quality and habitat parameters in streams of northwest Mississippi, examine the efficacy of an a priori classification system of stream channel evolution and condition class using macroinvertebrate communities, and examine short-term (<2 yr) temporal variation of macroinvertebrate communities. Separation of sites based on four condition classifications was not distinct. However, best attainable sites did plot together in an ordination analysis suggesting similarity in macroinvertebrate communities for least disturbed sites. Similarly, for stage of channel evolution, sites characterized by lack of bank failure and sinuous fluvial processes had relatively similar macroinvertebrate communities. Ordination analysis also indicated high temporal variation of macroinvertebrate communities. Reference sites (best attainable and stable sites) had more similar communities between years than unstable and impacted sites. Results of this study: (1) suggest total solids, total phosphorus concentration, percent substrate as sand, ammonia concentration, and conductivity were important variables for structuring stream macroinvertebrate communities in northwest Mississippi, (2) identify potential indicator taxa for assessing such streams based on water quality and physical habitat, (3) provide support for current a priori site classifications at the best attainable (least impacted) category relative to the macroinvertebrate communities, and (4) demonstrate that between-year variation is an important factor when assessing streams of north Mississippi and this variability may be related to the degree of stream degradation.

Control of the freshwater fouling bivalveCorbicula fluminea by halogenation

Mortality levels for adult and juvenile Asiatic clam,Corbicula fluminea, were determined after exposure to halogens (chlorine, bromine) in 28 to 32-day laboratory and field (industrial water supply) tests. Low levels of mortality (<53%) were generated in laboratory studies on exposure to constant doses of total residual chlorine (TRC) when mean test temperatures were <16‡C. Mortality levels were elevated (>53%) when test specimens were exposed to comparable TRC levels (0.2 to 1.0 mg/L) at temperatures in excess of 18‡C. Mortalities generated among adults by an initial 14-day low dose (0.25 mg/L TRC) followed by an 18-day high dose (0.50 to 1.00 mg/L TRC; >80% mortality) were comparable to those from a constant high dose (0.50 to 1.00 mg/L; 60 to 95% mortality). Adults and juveniles were comparably sensitive to halogen concentrations adequate for control. There is no substantial difference in the effectiveness of either chlorine or bromine in controlling adult and juvenile stages ofC. fluminea. Field studies conducted in the spring and fall produced markedly dissimilar results. Mortality levels during the spring field study exceeded 90% after 28 days of exposure to 0.25 mg/L TRC, while ambient temperatures rose from 20 to 25‡C. Mortality levels not exceeding 23% were observed among test organisms after 28 days of exposure to elevated TRC levels (<0.50 mg/L), while ambient temperatures were declining from 20 to 12‡C during October and November 1985.

Site-Specific Derivation of the Acute Copper Criteria for the Clinch River, Virginia

Previous studies indicated that inputs from the Clinch River Plant (CRP), a coal-burning, power-generating facility in Carbo, Virginia, caused impairment to transplanted freshwater mussels. These findings necessitated the examination of instream biological responses to CRP effluents. Therefore, our objective was to derive a site-specific Criterion Maximum Concentration (CMC) for copper (Cu), the toxic constituent of the effluent. This was accomplished by conducting acute toxicity tests with Cu using 17 different genera native to or currently residing in the Clinch River watershed. Four native unionids and a mayfly (Isonychia bicolor) had genus mean acute values of 60 µJ.g/L or lower (ranging from 37 to 60 µJ,g/L). With a GMAV of 88 µJ,g/L, Ceriodaphnia dubia ranked sixth among the 17 genera tested, and the fathead minnow, Pimephales promelas, ranked fourteenth with a GMAV of 310 µJ.g/L. Despite the sensitivity of the indigenous mussels tested, the site-specific CMC of 18 µJg/L was not substantially lower than the national CMC for Cu (20 µJ,g/L, hardness = 150 mg/L as CaCO3). While we conducted acute exposure tests, future investigations should incorporate both biomarker and population or community-level studies to determine low-level contaminant impacts on freshwater mussels.

Monitoring exposure of northern cardinals, Cardinalis cardinalis, to cholinesterase-inhibiting pesticides: enzyme activity, reactivations, and indicators of environmental stress.

Northern cardinals (Cardinalis cardinalis) frequently use agricultural field edges in northeast Arkansas, USA, and may be at risk of exposure to cholinesterase (ChE)-inhibiting pesticides. We monitored northern cardinal exposure to ChE-inhibiting pesticides by comparing plasma total ChE (TChE) activity to reference-derived benchmarks and TChE reactivations. Total ChE and acetylcholinesterase (AChE) were measured for 128 plasma samples from 104 northern cardinals from nine study sites. Of birds sampled from sites treated with ChE-inhibiting pesticides, 4.3% of the samples had TChE activities below the diagnostic threshold (2 standard deviations [SD] below the reference mean) and 8.7% of the samples had TChE reactivations. No difference was found in TChE (p = 0.553) and AChE (p = 0.288) activity between treated and reference sites; however, activity varied among treated sites (p = 0.003). These data do not suggest uniform exposure to individuals, but rather exposure was variable and likely influenced by mitigating factors at individual and site scales. Furthermore, monitoring of TChE reactivation appeared to be a more sensitive indicator of exposure than the diagnostic threshold. Fluctuating asymmetry (FA) was greater at agricultural sites than reference sites (p = 0.016), supporting the hypothesis that FA may be useful for assessing a combination of habitat- and contaminant-related environmental stress.