Toxicity of cigarette butts, and their chemical components, to marine and freshwater fish.

BACKGROUND: Cigarette butts are the most common form of litter, as an estimated 4.5 trillion cigarette butts are thrown away every year worldwide. Many chemical products are used during the course of growing tobacco and manufacturing cigarettes, the residues of which may be found in cigarettes prepared for consumption. Additionally, over 4000 chemicals may also be introduced to the environment via cigarette particulate matter (tar) and mainstream smoke. METHODS: Using US Environmental Protection Agency standard acute fish bioassays, cigarette butt-derived leachate was analysed for aquatic toxicity. Survival was the single endpoint and data were analysed using Comprehensive Environmental Toxicity Information System to identify the LC50 of cigarette butt leachate to fish. RESULTS: The LC50 for leachate from smoked cigarette butts (smoked filter + tobacco) was approximately one cigarette butt/l for both the marine topsmelt (Atherinops affinis) and the freshwater fathead minnow (Pimephales promelas). Leachate from smoked cigarette filters (no tobacco), was less toxic, with LC50 values of 1.8 and 4.3 cigarette butts/l, respectively for both fish species. Unsmoked cigarette filters (no tobacco) were also found to be toxic, with LC50 values of 5.1 and 13.5 cigarette butts/l, respectively, for both fish species. CONCLUSION: Toxicity of cigarette butt leachate was found to increase from unsmoked cigarette filters (no tobacco) to smoked cigarette filters (no tobacco) to smoked cigarette butts (smoked filter + tobacco). This study represents the first in the literature to investigate and affirm the toxicity of cigarette butts to fish, and will assist in assessing the potential ecological risks of cigarette butts to the aquatic environment.

Pulsed exposure toxicity testing: Baseline evaluations and considerations using copper and zinc with two marine species.

Methods to assess environmental impacts from episodic discharges on receiving water bodies need a more environmentally relevant and scientifically defensible toxicity test design. Many permittees are regularly required to conduct 96-h toxicity tests on discharges associated with events that are generally less than 24 h in duration. Current standardized methods do not adequately reflect these episodic discharge conditions at either the point of compliance nor as it mixes with the receiving environment. In order to evaluate more representative biological effects, an alternative toxicity approach is described incorporating pulsed exposures of effluents and subsequent transfer of test organisms to clean water for the remainder of the test. This pulsed exposure protocol incorporates a slight modification to USEPA Whole Effluent Toxicity (WET) chronic and acute methods for two marine species, purple sea urchin embryos, Strongylocentrotus purpuratus, and juvenile mysid shrimp Americamysis bahia. Tests were performed with toxicants using standard static (96 h) and pulsed (6, 12, and 26 h) exposures. Following pulsed exposures, organisms were transferred to uncontaminated seawater for the remainder of the 96-h test period. Results for these species and endpoints indicated that the sensitivity of these species to copper and zinc were up to two orders of magnitude greater using standard continuous exposures compared to shorter pulsed exposures. Additional considerations assessed included timing of the onset of a pulse and latent effects following an exposure. This modified approach requires minimal modification to current standard methods and increases the realism to more accurately assess toxic effects resulting from episodic discharges.

Macrofaunal recolonization of copper-contaminated sediments in San Diego Bay.

Effects of Cu-loading on macrofaunal recolonization were examined in Shelter Island Yacht Basin (San Diego Bay, California). Sediments with high and low Cu levels were defaunated and Cu-spiked, translocated, and then placed back into the environment. These demonstrated that the alteration observed in benthic communities associated with Cu contamination occurs during initial recolonization. After a 3-month exposure to sediments with varying Cu levels, two primary colonizing communities were identified: (1) a "mouth assemblage" resembling adjacent background fauna associated with low-Cu levels that was more diverse and predominantly dominated by surface- and subsurface-deposit feeders, burrowers, and tube builders, and (2) a "head assemblage" resembling adjacent background fauna associated with high-Cu concentrations, with few dominant species and an increasing importance of carnivores and mobile epifauna. Cu loading can cause reduced biodiversity and lower structural complexity that may last several months if high concentrations persist, with a direct effect on community functioning.