Penetration of herbicides to groundwater in an unconfined chalk aquifer following normal soil applications

The persistence and penetration of the herbicides isoproturon and chlorotoluron in an unconfined chalk aquifer has been monitored over a 4-year period through soil sampling, shallow coring and groundwater monitoring. Chlorotoluron was applied on plots as a marker compound, having never been used previously on that, or surrounding fields. The fieldsite had a 5 degree slope with soil depths of 0.5 to 1.5 m and a water table between 20 and 5 m from the soil surface. Where the water table was deepest (9-20 m below surface (mbs)) little or no positive herbicide detections were made. However, where the water table was at only 4-5 mbs, a regular pesticide signal of around 0.1 microg/l for isoproturon and chlorotoluron could be distinguished. Over the winter recharge period automatic borehole samplers revealed a series of short-lived peaks of isoproturon and chlorotoluron reaching up to 0.8 microg/l. This is consistent with a preferential flow mechanism operating at this particular part of the field. Such peaks were occurring over 2 years after the last application of these compounds. Shallow coring failed to uncover any significant pesticide pulse moving through the deep unsaturated zone matrix at the fieldsite.     

The ecological and economic potential of carbon sequestration in forests: examples from South America

Costs of reforestation projects determine their competitiveness with alternative measures to mitigate rising atmospheric CO2 concentrations. We quantify carbon sequestration in above-ground biomass and soils of plantation forests and secondary forests in two countries in South America-Ecuador and Argentina-and calculate costs of temporary carbon sequestration. Costs per temporary certified emission reduction unit vary between 0.1 and 2.7 USD Mg(-1) CO2 and mainly depend on opportunity costs, site suitability, discount rates, and certification costs. In Ecuador, secondary forests are a feasible and cost-efficient alternative, whereas in Argentina reforestation on highly suitable land is relatively cheap. Our results can be used to design cost-effective sink projects and to negotiate fair carbon prices for landowners.     

Seat strength in rear body block tests

Purpose: This study collected and analyzed available testing of motor vehicle seat strength in rearward loading by a body block simulating the torso of an occupant. The data were grouped by single recliner, dual recliner, and all belts to seat (ABTS) seats.

Methods: The strength of seats to rearward loading has been evaluated with body block testing from 1964 to 2008. The database of available tests includes 217 single recliner, 65 dual recliner, and 18 ABTS seats. The trends in seat strength were determined by linear regression and differences between seat types were evaluated by Student's t-test. The average peak moment and force supported by the seat was determined by decade of vehicle model year (MY).

Results: Single recliner seats were used in motor vehicles in the 1960s to 1970s. The average strength was 918 ± 224 Nm (n = 26) in the 1960s and 1,069 ± 293 Nm (n = 65) in the 1980s. There has been a gradual increase in strength over time. Dual recliner seats started to phase into vehicles in the late 1980s. By the 2000s, the average strength of single recliner seats increased to 1,501 ± 335 Nm (n = 14) and dual recliner seats to 2,302 ± 699 Nm (n = 26). Dual recliner seats are significantly stronger than single recliner seats for each decade of comparison (P < .001). The average strength of ABTS seats was 4,395 ± 1,185 in-lb for 1989–2004 MY seats (n = 18). ABTS seats are significantly stronger than single or dual recliner seats (P < .001). The trend in ABTS strength is decreasing with time and converging toward that of dual recliner seats.

Conclusions: Body block testing is an quantitative means of evaluating the strength of seats for occupant loading in rear impacts. There has been an increase in conventional seat strength over the past 50 years. By the 2000s, most seats are 1,700–3,400 Nm moment strength. However, the safety of a seat is more complex than its strength and depends on many other factors.     

Environmental risk assessment for trisodium [S,S]-ethylene diamine disuccinate, a biodegradable chelator used in detergent applications

Environmental safety data are presented for [S,S]-Ethylene Diamine Disuccinate ([S,S]EDDS), a new, biodegradable, strong transition metal chelator. An environmental risk assessment for its use in detergent applications, which takes into account the chelating properties of [S,S]-EDDS, is proposed.

A property of [S,S]-EDDS that distinguishes it from other strong transition metal chelators is its, “ready” and transparent (no recalcitrant metabolites) biodegradation profile. Because its sorption to activated sludge solids is low ( Kp of 40 1/kg), removal of [S,S]EDDS during sewage treatment, which is greater than 96% as determined by the Continuous Activated Sludge test , is mainly ascribed to biodegradation. At projected use volumes in detergent applications [S,S] - EDDS predicted steady-state concentration in rivers leaving the mixing zone will be below 5 pg/I due to rapid biodegradation. [S,S]-EDDS exhibits low toxicity to fish and Daphnia ( both EC₅₀s> 1000 mg/l). By contrast, due to limitation of the algal test for chelators apparent toxicity was observed (EC₅₀ = 0.290 mg/l, NOEC - No observable Effect Concentration = 0.125 mg/l). Schowanek et al. [1] demonstrated that this is not toxicity sensu stricto but a chelation effect of trace metals in the test medium and of resulting essential nutrients limitation. This requires specific attention when the results of algal toxicity are to be extrapolated to a field situation to perform realistic risk assessment. Metal speciation calculations, using MINEQL+, show that at the predicted environmental concentrations of [S,S] - EDDS (1–5 μg/l), such a chelation effect would be insignificant. These calculations allow to estimate the NOEC for chelation effects in the field to be in the range of 0.250-0.500 mg/l, depending on the background water chemistry. These values are well above the laboratory NOEC.

An environmental risk assessment was performed using the EUSES (1.0) program. EUSES is currently the EU recommended tool for conducting risk assessments (TGD 1995). It was applied to estimate the river water and soil concentrations from production, formulation and private use life stages. The estimated PEC/PNEC ratio in all relevant environmental compartments is smaller than 1, indicating “no immediate concern” at the anticipated usage level.     

The cost of host egg damage caused by a brood parasite: experiments on great spotted cuckoos (Clamator glandarius) and magpies (Pica pica)

Adult great spotted cuckoos, Clamator glandarius, frequently damage one or more eggs of their magpie host, Pica pica, without removing or eating them. The presence of damaged host eggs could signal parasitism thereby increasing the probability that the parasitic egg is ejected. This hypothesis was tested by experimentally introducing a model cuckoo egg with or without damaged host eggs. Magpie responses to experimental parasitism did not differ significantly between treatments implying that damaged host eggs are not used by magpies to assess parasitism. We followed the fate of magpie eggs naturally damaged by the great spotted cuckoo or experimentally damaged by us. Host response was very similar for naturally or experimentally damaged host eggs, but varied significantly according to the type of egg damage, eggs being removed more frequently when pecked than crushed, while cracked eggs were never removed. However, the egg damage that most readily causes egg removal is albumen leakage. Received: 30 November 1998 / Received in revised form: 7 June 1999 / Accepted: 12 June 1999     

Mating effort and space use of an alpine ungulate during the rut

In ungulates, the rut generally leads to increased intra and interpopulation movements for males. Because movements induce energetic costs and missed feeding opportunities, they could be an indication of male mating effort. We studied space use of 44 male mountain goats (Oreamnos americanus) from three neighboring subpopulations in southeast Alaska, during the rut from 2005 to 2008. Using mixed models and an information theoretic approach with AIC, we analyzed the relationships between individual traits of males and their space use. We found no indication of breeding migration between subpopulations. Distances between individual seasonal ranges were not related to any individual trait. Daily movements, home range sizes, and total distance traveled during the rut did not vary with mass or age of individuals. As such, effects of individual traits on male space use during the rut appear weak and observed space use patterns do not support any of the main mating effort hypotheses.     

The repeatability of avian egg ejection behaviors across different temporal scales,breeding stages,female ages and experiences

An evolutionarily fundamental, yet rarely examined, aspect of host–parasite arms races is the repeatability of individual host responses to parasitism. We examined the repeatability of egg ejection, and the latency to eject, across a time-scale of days (within one breeding attempt), weeks and months (between breeding attempts within one breeding season), and years (across different breeding seasons). The ejection of non-mimetic model eggs by European blackbirds, Turdus merula, showed overall high repeatability (r?~?0.70) and, similar to empirical patterns on most other behavioral traits already studied, showed decreasing repeatability with time. In contrast, latency to ejection showed negligible repeatability overall (r ~0.20) and did not change with time. Ejection rates, latencies to ejection and the repeatability of egg ejection did not differ between young and old females. Previous experience with experimentation (number of model eggs the female received before the focal trial) marginally non-significantly covaried with egg ejection (positively) and with latency to egg ejection (negatively). Repeatability estimates for both egg ejection and latency to egg ejection at the within one breeding attempt time-scale did not statistically differ from those reported in a previous study of a different blackbird population (introduced population in New Zealand). To our knowledge, this is the first comparison of behavioral repeatability between a native vs. introduced population of any animal species.