Marion Nipper

Toxicological and chemical assessment of ordnance compounds in marine sediments and porewaters

Toxicological and chemical studies were performed with a silty and a sandy marine sediment spiked with 2,6-dinitrotoluene (2,6-DNT), 2,4,6-trinitrophenylmethylnitramine (tetryl), or 2,4,6-trinitrophenol (picric acid). Whole sediment toxicity was analyzed by the 10-day survival test with the amphipod Ampelisca abdita, and porewater toxicity tests assessed macro-algae (Ulva fasciata) zoospore germination and germling growth, sea urchin (Arbacia punctulata) embryological development, and polychaete (Dinophilus gyrociliatus) survival and reproduction. Whole sediments spiked with 2,6-DNT were not toxic to amphipods. The fine-grained sediment spiked with tetryl was also not acutely toxic. The tetryl and picric acid LC50 values in the sandy sediment were 3.24 and 144 mg/kg dry weight, respectively. The fine-grained sediment spiked with picric acid generated a U-shaped concentration-response curve in the amphipod test, with increased survival both in the lowest and highest concentration. Grain-size distribution and organic carbon content strongly influenced the behavior of ordnance compounds in spiked sediments. Very low concentrations were measured in some of the treatments and irreversible binding and biodegradation are suggested as the processes responsible for the low measurements. Porewater toxicity varied with its sedimentary origin and with ordnance compound. The sea urchin embryological development test tended to be the least sensitive. Tetryl was the most toxic chemical in all porewater tests, and picric acid the least toxic. Samples spiked with 2,6-DNT contained a degradation product identified as 2-methyl-3-nitroaniline (also known as 2-amino-6-nitrotoluene), and unidentified peaks, possibly degradation products, were also seen in some of the picric acid- and tetryl-spiked samples. Degradation products may have played a role in observed toxicity.

Current approaches and future directions for contaminant-related impact assessments in coastal environments: Brazilian perspective

Abstract Coastal ecosystems are subject to the discharge of contaminants via sewage, industrial effluents, storm water runoff, dredged material and accidental chemical spills. The majority of contaminants reaching the ocean tend to be adsorbed to particulate matter and eventually settle on the ocean floor, where they can deleteriously affect the sediment-associated community. The degree to which a receiving body is impacted is usually assessed by the analysis of the sediments from the area of concern. If chemical data generated by monitoring programs are available, they can be compared to Sediment Quality Guidelines to help identify a potential problem. A more cost-effective approach involves the use of a sensitive toxicity test to identify areas of concern, with comprehensive chemical analyses conducted at a later stage and focusing on the toxic sites identified in the initial screening survey. More complex studies involve the assessment of the benthic communities, in addition to toxicity tests and chemical analyses can be conducted. While methodologies for chemical and benthic community assessments are relatively well established, several approaches can be used to determine sediment toxicity, including acute or chronic tests, conducted in the laboratory or in situ, on the whole sediment or the liquid phase. Several factors should be considered when interpreting toxicity test results, such as the enhancement of toxicity by the photo-oxidation of organic chemicals by ultraviolet light (UV), and confounding factors such as salinity, ammonia, sulfides, particle size distribution, organic matter content, and acid volatile sulfides (AVS). Once an impact has been identified, toxicity identification evaluation (TIE) procedures can be applied to help establish the chemical or classes of chemicals responsible for the observed adverse effects. The international and Brazilian scientific literatures are reviewed to illustrate these approaches.

Recent advances in the use of meiofaunal polychaetes for ecotoxicological assessments

While whole sediment toxicity tests with macrofaunal polychaetes are well developed and standardized, they are oftentimes not very sensitive to environmental contaminants. Meiofaunal polychaetes, however, are sensitive to contaminants, easy to culture, and representative of the interstitial habitat. These are desirable attributes for ecotoxicological assessments of marine and estuarine sediments. The meiofaunal polychaete, Dinophilus gyrociliatus Schmidt, 1857, is a cosmopolitan species that has become a useful tool for ecotoxicological assessments, particularly for its use in toxicity testing with sediment pore waters. Due to its short life cycle it is suitable for sublethal toxicity tests, with egg production by the females as a sensitive endpoint, which can be assessed in a 7-day exposure period. Toxicity assessments of pore waters from an industrialized bay in Texas, U.S.A., and of pore waters from sediments spiked with nitroaromatic explosives, demonstrated that the D. gyrociliatus reproduction endpoint was consistently among the most sensitive, when compared to early-life stage tests with several other marine species, including macro-algae, sea urchins and fish. There was also excellent agreement among the results of porewater tests with D. gyrociliatus, nauplii of the meiofaunal copepod, Longipedia americana, and embryos of the sea urchin, Arbacia punctulata in a survey with pore waters extracted from sediments collected in the vicinity of an oil platform in the Gulf of Mexico, where metals were the primary contaminants of concern.

Survey of Marine Contamination from Mining-Related Activities on Marinduque Island, Philippines: Porewater Toxicity and Chemistry

Pore waters were collected for toxicological and chemical analyses at several stations on the coast of Marinduque, near the mouths of the Boac and Mogpog rivers, and near the causeways formed by mine tailings disposal. Porewater samples were also collected at the Tres Reyes Marine Reserve, so that these non-contaminated samples could serve as a reference for test performance. Sea urchin embryological development and fertilization were only significantly impaired by two porewater samples, suggesting the presence of contaminants in toxic amounts at those stations. The toxic samples were collected near the up current side of the Calancan (Marcopper) mine tailings causeway (stations 2 and 3). The pore water from station 2 also had the highest levels of heavy metals, particularly cadmium, cobalt, copper, nickel, lead and zinc. The concentrations of cobalt, nickel and zinc were also elevated at station 3. Copper concentrations were also elevated at the two river mouth stations (8 and 9) and near the CMI tailings causeway (station 7). Visual observations also indicated biological degradation due to heavy siltation and smothered coral at a gradient off the Calancan causeway, suggesting that siltation might also be causing a physical impact. This preliminary survey suggests that effects related to past mining activities are still evident and warrant a more comprehensive study to assess their severity and areal extent.