Biomedical subjects

T Crommentuijn

Publications and source records attributed to T Crommentuijn.

5 recordsLinked to original sources

PubMed2001

Environmental quality standards: endpoints or triggers for a tiered ecological effect assessment approach?

The recently derived Dutch Environmental Quality Standards (EQS) for water, soil, and sediment for approximately 170 substances have been evaluated. Three methods have been used to derive the Dutch EQS. Independent of how the EQS were derived, they are given equal weight in Dutch environmental policy. Scientifically, the three methods may deserve different weights. For example, for soil and sediment, the least reliable method had to be applied to derive most of the EQS. Ecological effects in these compartments may be either overestimated or underestimated. A multitiered approach is proposed, which is relevant for all parties involved, including other countries, and which may help improve ecological effect assessment.

Conservation of Natural Resources↗

PubMed1997

Environmental quality objectives for 10 polycyclic aromatic hydrocarbons (PAHs).

Environmental quality objectives (EQOs) for water, soil, and sediment are derived for polycyclic aromatic hydrocarbons (PAHs). EQOs are an important instrument in the effects-oriented environmental policy of the Dutch Ministry of the Environment. These EQOs should be set in such a way that protection of organisms in all compartments is ensured. As intermedia transport of chemicals occurs, this means that EQOs derived for individual compartments have to be harmonized. EQOs are based on scientifically derived risk limits: maximum permissible concentrations (MPCs) and the negligible concentrations (NCs). MPCs are concentrations above which the risk of adverse effects is considered unacceptable. The NC is defined as the MPC/100 and takes possible effects of combination toxicity due to the presence of other substances into account. In this paper MPCs are derived for haphthalene, anthracene, phenanthrene, fluoranthene, benzo[a]anthracene, chrysene, benzo[k]fluoranthene, benzo[a]pyrene, benzo[ghi]perylene, and indeno[1,2,3-cd]pyrene. The MPCs for these PAHs are for water 1.2, 0.07, 0.30, 0.30, 0.01, 0.34, 0.04, 0.05, 0.03, and 0.04 micrograms/liter, respectively; for soil 0.14, 0.12, 0.51, 2.6, 0.25, 10.7, 2.4. 0.26, 7.5, and 5.9 mg/kg, respectively; and for sediment 0.14, 0.12, 0.51, 2.6. 0.36, 10.7, 2.4, 2.7, 7.5, and 5.9 mg/kg, respectively.

Air Pollutants↗

PubMed1997

Added risk approach to derive maximum permissible concentrations for heavy metals: how to take natural background levels into account.

A unified method is presented to derive maximum permissible concentrations (MPCs) of xenobiotic and naturally occurring substances. The method relies upon risk limitation expressed as the maximum potentially affected fraction of all possible species (PAFmax) in a component ecosystem, due to a bioavailable concentration of the considered substance. For xenobiotic compounds the method is simplified to the "HC5 approach," i.e., the MPC equals the hazardous concentration at which 5% of the species are unprotected. If the natural background of a substance is (partly) bioavailable, the related background effect, also expressed as PAF, is taken into account in deriving a MPC. Examples are given and MPCs for zinc, chromium, cadmium, copper, and lead for different levels of bioavailability in water are developed.

Animals↗

PubMed1995

Sublethal sensitivity index as an ecotoxicity parameter measuring energy allocation under toxicant stress: application to cadmium in soil arthropods.

Toxic substances may affect the life history of a species in a variety of ways. Different species maintain different priorities in coping with the physiological consequences of toxicant-induced stress. This is expressed by changes in energy allocation to different life-history characteristics which may have great consequences for the response at the population level. In this study the terrestrial invertebrates Platynothrus peltifer (Oribatida), Orchesella cincta, Folsomia candida (Collembola), and Porcellio scaber (Isopoda) were chosen to evaluate species-specific sensitivity of life histories. Effects on reproduction and weight increase under exposure to cadmium in the food were analyzed. The answer to the question of which species is the most sensitive depends on the parameter chosen. A comparison of sensitivity on the basis of sublethal effects showed P. peltifer to be the most sensitive species; on the basis of lethal effects however, the species O. cincta was the most sensitive. This discrepancy between effect parameters resulted in differences between the distance of the concentrations at which lethal and sublethal effects occur for different species. The ratio between the lethal effect concentration and the sublethal effect concentration is called the sublethal sensitivity index (SSI) and is proposed as a parameter expressing maintenance of sublethal functions under toxicant stress. The SSI seems to be a valuable parameter for evaluating the likelihood of population-level effects under toxicant stress. To extrapolate effects found in the laboratory to the field situation, more attention should be paid to the relationships between effects on life-history parameters and effects on population growth.

Animals↗

PubMed1993

Influence of cadmium on life-history characteristics of Folsomia candida (Willem) in an artificial soil substrate.

To understand the consequences of soil pollution on higher levels of biological organization, the chain of effects of cadmium on several interrelated responses was studied in a chronic toxicity experiment using the collembolan species Folsomia candida (Willem) in an artificial soil. The individual parameters survival, growth, and number of offspring were determined after different time intervals up to 9 weeks. The accumulation of cadmium in springtails and the population increase during the experimental period were also determined. By combining all the mentioned parameters and their development in time, a detailed picture of the action of cadmium on F. candida was obtained. In order of decreasing sensitivity the EC50 values for Von Bertalanffy growth, number of offspring, population increase, and survival were 256, > 326, 475, and 850 micrograms Cd/g dry soil, respectively. The ultimate LC50 value and also the equilibrium body burden were reached after about 20 days. Reproduction started later because of retarded growth, but was not affected directly and eventually reached the control level. The results are discussed in light of the seemingly contradictory ideas of Halbach (1984, Hydrobiologia 109, 79-96) and Meyer et al. (1987, Environ. Toxicol. Chem. 6, 115-126) about the sensitivity of individual and population parameters. It appears to be very important to know how individual parameters develop in time so that the most sensitive parameter and the consequences for higher levels of biological organization can be determined.

Animals↗